v1.4.8

Co-authored-by: Andrew Eisenberg <aeisenberg@github.com>

.gitattributes

@@ -12,3 +12,10 @@ yarn.lock                    merge=binary
 # For more information, see this issue: https://github.com/Microsoft/web-build-tools/issues/1088
 #
 *.json                       linguist-language=JSON-with-Comments
+
+# Reduce incidence of needless merge conflicts on CHANGELOG.md
+# The man page at
+# https://mirrors.edge.kernel.org/pub/software/scm/git/docs/gitattributes.html
+# suggests that this might interleave lines arbitrarily, but empirically
+# it keeps added chunks contiguous
+CHANGELOG.md                merge=union

.github/ISSUE_TEMPLATE/bug_report.md

@@ -10,7 +10,12 @@ assignees: ''
 **Describe the bug**
 A clear and concise description of what the bug is.
 
-**To Reproduce**
+**Version**
+The CodeQL and VS Code version in which the bug occurs.
+<!-- To copy version information for the CodeQL extension, click "CodeQL CLI vX.X.X" in the status bar at the bottom of the screen. 
+To copy detailed version information for VS Code itself, see https://code.visualstudio.com/docs/supporting/FAQ#_how-do-i-find-the-version. -->
+
+**To reproduce**
 Steps to reproduce the behavior.
 
 **Expected behavior**

.github/ISSUE_TEMPLATE/new-extension-release.md

@@ -9,7 +9,7 @@ assignees: ''
 ---
 
 - [ ] Update this issue title to refer to the version of the release
-- [ ] Trigger a release build on Actions by adding a new tag on master of the format `vxx.xx.xx`
+- [ ] Trigger a release build on Actions by adding a new tag on branch `main` of the format `vxx.xx.xx`
 - [ ] Monitor the status of the release build in the `Release` workflow in the Actions tab.
 - [ ] Download the VSIX from the draft GitHub release that is created when the release build finishes.
 - [ ] Log into the [Visual Studio Marketplace](https://marketplace.visualstudio.com/manage/publishers/github).

.github/codeql/codeql-config.yml

@@ -0,0 +1,12 @@
+name: "CodeQL config"
+queries:
+  - name: Run standard queries
+    uses: security-and-quality
+  - name: Run custom javascript queries
+    uses: ./.github/codeql/queries
+paths:
+  - ./extensions/ql-vscode
+paths-ignore:
+  - '**/node_modules'
+  - '**/build'
+  - '**/out'

.github/codeql/queries/assert-pure.ql

@@ -0,0 +1,21 @@
+/**
+ * @name Unwanted dependency on vscode API
+ * @kind problem
+ * @problem.severity error
+ * @id vscode-codeql/assert-pure
+ * @description The modules stored under `pure` and tested in the `pure-tests`
+ * are intended to be "pure".
+ */
+import javascript
+
+class VSCodeImport extends ASTNode {
+  VSCodeImport() {
+    this.(Import).getImportedPath().getValue() = "vscode"
+  }
+}
+
+from Module m, VSCodeImport v
+where
+  m.getFile().getRelativePath().regexpMatch(".*src/pure/.*")  and
+  m.getAnImportedModule*().getAnImport() = v
+select m, "This module is not pure: it has a transitive dependency on the vscode API imported $@", v, "here"

.github/codeql/queries/qlpack.yml

@@ -0,0 +1,3 @@
+name: vscode-codeql-custom-queries-javascript
+version: 0.0.0
+libraryPathDependencies: codeql-javascript

.github/pull_request_template.md

@@ -1,12 +1,12 @@
 <!-- Thank you for submitting a pull request. Please read our pull request guidelines before
   submitting your pull request:
-  https://github.com/github/vscode-codeql/blob/master/CONTRIBUTING.md#submitting-a-pull-request.
+  https://github.com/github/vscode-codeql/blob/main/CONTRIBUTING.md#submitting-a-pull-request.
 -->
 
 Replace this with a description of the changes your pull request makes.
 
 ## Checklist
 
-- [ ] [CHANGELOG.md](https://github.com/github/vscode-codeql/blob/master/extensions/ql-vscode/CHANGELOG.md) has been updated to incorporate all user visible changes made by this pull request.
+- [ ] [CHANGELOG.md](https://github.com/github/vscode-codeql/blob/main/extensions/ql-vscode/CHANGELOG.md) has been updated to incorporate all user visible changes made by this pull request.
 - [ ] Issues have been created for any UI or other user-facing changes made by this pull request.
-- [ ] `@github/product-docs-dsp` has been cc'd in all issues for UI or other user-facing changes made by this pull request.
+- [ ] `@github/docs-content-codeql` has been cc'd in all issues for UI or other user-facing changes made by this pull request.

.github/workflows/codeql.yml

@@ -0,0 +1,31 @@
+name: "Code Scanning - CodeQL"
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+  schedule:
+    - cron: '21 17 * * 0'
+
+jobs:
+  codeql:
+    runs-on: ubuntu-latest
+
+    permissions:
+      contents: read
+      security-events: write
+      pull-requests: read
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v2
+
+      - name: Initialize CodeQL
+        uses: github/codeql-action/init@main
+        with:
+            languages: javascript
+            config-file: ./.github/codeql/codeql-config.yml
+
+      - name: Perform CodeQL Analysis
+        uses: github/codeql-action/analyze@main

.github/workflows/label-issue.yml

@@ -0,0 +1,15 @@
+name: Label issue
+on:
+  issues:
+    types: [opened]
+
+jobs:
+  label:
+    name: Label issue
+    runs-on: ubuntu-latest
+    steps:
+      - name: Label issue
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: |
+          echo '{"labels": ["VSCode"]}' | gh api repos/${{ github.repository }}/issues/${{ github.event.issue.number }}/labels --input -

.github/workflows/main.yml

@@ -1,5 +1,10 @@
 name: Build Extension
-on: [push, pull_request]
+on:
+  workflow_dispatch:
+  pull_request:
+  push:
+    branches:
+      - main
 
 jobs:
   build:
@@ -16,13 +21,20 @@ jobs:
 
       - uses: actions/setup-node@v1
         with:
-          node-version: '10.18.1'
+          node-version: '14.14.0'
+
+      - name: Install dependencies
+        working-directory: extensions/ql-vscode
+        run: |
+          npm install
+        shell: bash
 
       - name: Build
+        working-directory: extensions/ql-vscode
+        env:
+          APP_INSIGHTS_KEY: '${{ secrets.APP_INSIGHTS_KEY }}'
         run: |
-          cd build
-          npm install
-          npm run build-ci
+          npm run build
         shell: bash
 
       - name: Prepare artifacts
@@ -32,7 +44,7 @@ jobs:
           cp dist/*.vsix artifacts
 
       - name: Upload artifacts
-        uses: actions/upload-artifact@master
+        uses: actions/upload-artifact@v2
         if: matrix.os == 'ubuntu-latest'
         with:
           name: vscode-codeql-extension
@@ -52,19 +64,25 @@ jobs:
 
       - uses: actions/setup-node@v1
         with:
-          node-version: '10.18.1'
+          node-version: '14.14.0'
 
-      # We have to build the dependencies in `lib` before running any tests.
-      - name: Build
+      - name: Install dependencies
+        working-directory: extensions/ql-vscode
         run: |
-          cd build
           npm install
-          npm run build-ci
+        shell: bash
+
+      - name: Build
+        working-directory: extensions/ql-vscode
+        env:
+          APP_INSIGHTS_KEY: '${{ secrets.APP_INSIGHTS_KEY }}'
+        run: |
+          npm run build
         shell: bash
 
       - name: Lint
+        working-directory: extensions/ql-vscode
         run: |
-          cd extensions/ql-vscode
           npm run lint
 
       - name: Install CodeQL
@@ -77,27 +95,76 @@ jobs:
         shell: bash
 
       - name: Run unit tests (Linux)
+        working-directory: extensions/ql-vscode
         if: matrix.os == 'ubuntu-latest'
         run: |
-          cd extensions/ql-vscode
           CODEQL_PATH=$GITHUB_WORKSPACE/codeql-home/codeql/codeql npm run test
 
       - name: Run unit tests (Windows)
         if: matrix.os == 'windows-latest'
+        working-directory: extensions/ql-vscode
         run: |
-          cd extensions/ql-vscode
           $env:CODEQL_PATH=$(Join-Path $env:GITHUB_WORKSPACE -ChildPath 'codeql-home/codeql/codeql.exe')
           npm run test
 
       - name: Run integration tests (Linux)
         if: matrix.os == 'ubuntu-latest'
+        working-directory: extensions/ql-vscode
         run: |
-          cd extensions/ql-vscode
           sudo apt-get install xvfb
           /usr/bin/xvfb-run npm run integration
 
       - name: Run integration tests (Windows)
         if: matrix.os == 'windows-latest'
+        working-directory: extensions/ql-vscode
         run: |
-          cd extensions/ql-vscode
           npm run integration
+
+  cli-test:
+    name: CLI Test
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [ubuntu-latest, windows-latest]
+        version: ['v2.2.6', 'v2.3.3', 'v2.4.5', 'v2.4.6', 'v2.5.3']
+    env:
+      CLI_VERSION: ${{ matrix.version }}
+      TEST_CODEQL_PATH: '${{ github.workspace }}/codeql'
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+
+      - uses: actions/setup-node@v1
+        with:
+          node-version: '14.14.0'
+
+      - name: Install dependencies
+        working-directory: extensions/ql-vscode
+        run: |
+          npm install
+        shell: bash
+
+      - name: Build
+        working-directory: extensions/ql-vscode
+        run: |
+          npm run build
+        shell: bash
+
+      - name: Checkout QL
+        uses: actions/checkout@v2
+        with:
+          repository: github/codeql
+          path: codeql
+
+      - name: Run CLI tests (Linux)
+        working-directory: extensions/ql-vscode
+        if: matrix.os == 'ubuntu-latest'
+        run: |
+          /usr/bin/xvfb-run npm run cli-integration
+
+      - name: Run CLI tests (Windows)
+        working-directory: extensions/ql-vscode
+        if: matrix.os == 'windows-latest'
+        run: |
+          npm run cli-integration

.github/workflows/release.yml

@@ -6,25 +6,20 @@
 
 name: Release
 on:
-  push:
-    # Path filters are not evaluated for pushes to tags.
-    # (source: https://help.github.com/en/github/automating-your-workflow-with-github-actions/workflow-syntax-for-github-actions#onpushpull_requestpaths)
-    # So this workflow is triggered in the following events:
-    # - Release event: a SemVer tag, e.g. v1.0.0 or v1.0.0-alpha, is pushed
-    tags:
-      - 'v[0-9]+.[0-9]+.[0-9]+*'
-    # OR
-    # - Test event: this file is modified on a branch in the main repo containing `/actions/` in the name.
-    branches:
-      - '**/actions/**'
+  pull_request:
     paths:
       - '**/workflows/release.yml'
 
+  workflow_dispatch:
+
+  push:
+    tags:
+      - 'v[0-9]+.[0-9]+.[0-9]+*'
+
 jobs:
   build:
     name: Release
     runs-on: ubuntu-latest
-    # TODO Share steps with the main workflow.
     steps:
       - name: Checkout
         uses: actions/checkout@v2
@@ -33,12 +28,19 @@ jobs:
         with:
           node-version: '10.18.1'
 
-      - name: Build
+      - name: Install dependencies
         run: |
-          cd build
-          npm install
-          # Release build instead of dev build.
-          npm run build-release
+          cd extensions/ql-vscode
+          npm ci
+        shell: bash
+
+      - name: Build
+        env:
+          APP_INSIGHTS_KEY: '${{ secrets.APP_INSIGHTS_KEY }}'
+        run: |
+          echo "APP INSIGHTS KEY LENGTH: ${#APP_INSIGHTS_KEY}"
+          cd extensions/ql-vscode
+          npm run build -- --release
         shell: bash
 
       - name: Prepare artifacts
@@ -55,11 +57,8 @@ jobs:
           REF_NAME="$(echo ${{ github.ref }} | sed -e 's:^refs/tags/::' | sed -e 's:/:-:g')"
           echo "::set-output name=ref_name::$REF_NAME"
 
-      # Uploading artifacts is not necessary to create a release.
-      # This is just in case the release itself fails and we want to access the built artifacts from Actions.
-      # TODO Remove if not useful.
       - name: Upload artifacts
-        uses: actions/upload-artifact@master
+        uses: actions/upload-artifact@v2
         with:
           name: vscode-codeql-extension
           path: artifacts
@@ -93,12 +92,16 @@ jobs:
           asset_name: ${{ format('vscode-codeql-{0}.vsix', steps.prepare-artifacts.outputs.ref_name) }}
           asset_content_type: application/zip
 
-      # The checkout action does not fetch the master branch.
-      # Fetch the master branch so that we can base the version bump PR against master.
-      - name: Fetch master branch
+      ###
+      # Do Post release work: version bump and changelog PR
+      # Only do this if we are running from a PR (ie- this is part of the release process)
+
+      # The checkout action does not fetch the main branch.
+      # Fetch the main branch so that we can base the version bump PR against main.
+      - name: Fetch main branch
         run: |
-          git fetch --depth=1 origin master:master
-          git checkout master
+          git fetch --depth=1 origin main:main
+          git checkout main
 
       - name: Bump patch version
         id: bump-patch-version
@@ -110,8 +113,14 @@ jobs:
           NEXT_VERSION="$(npm version patch)"
           echo "::set-output name=next_version::$NEXT_VERSION"
 
+      - name: Add changelog for next release
+        if: success()
+        run: |
+          cd extensions/ql-vscode
+          perl -i -pe 's/^/## \[UNRELEASED\]\n\n/ if($.==3)' CHANGELOG.md
+
       - name: Create version bump PR
-        uses: peter-evans/create-pull-request@c7b64af0a489eae91f7890f2c1b63d13cc2d8ab7 # v2.4.2
+        uses: peter-evans/create-pull-request@c7f493a8000b8aeb17a1332e326ba76b57cb83eb # v3.4.1
         if: success()
         with:
           token: ${{ secrets.GITHUB_TOKEN }}
@@ -119,4 +128,41 @@ jobs:
           title: Bump version to ${{ steps.bump-patch-version.outputs.next_version }}
           body: This PR was automatically generated by the GitHub Actions release workflow in this repository.
           branch: ${{ format('version/bump-to-{0}', steps.bump-patch-version.outputs.next_version) }}
-          base: master
+          base: main
+
+  vscode-publish:
+    name: Publish to VS Code Marketplace
+    needs: build
+    environment: publish-vscode-marketplace
+    runs-on: ubuntu-latest
+    env:
+      VSCE_TOKEN: ${{ secrets.VSCE_TOKEN }}
+    steps:
+      - name: Download artifact
+        uses: actions/download-artifact@v2
+        with:
+          name: vscode-codeql-extension
+
+      - name: Publish to Registry
+        run: |
+          npx vsce publish -p $VSCE_TOKEN --packagePath *.vsix || \
+            echo "Failed to publish to VS Code Marketplace. \
+                  If this was an authentication problem, please make sure the \
+                  auth token hasn't expired."
+
+  open-vsx-publish:
+    name: Publish to Open VSX Registry
+    needs: build
+    environment: publish-open-vsx
+    runs-on: ubuntu-latest
+    env:
+      OPEN_VSX_TOKEN: ${{ secrets.OPEN_VSX_TOKEN }}
+    steps:
+      - name: Download artifact
+        uses: actions/download-artifact@v2
+        with:
+          name: vscode-codeql-extension
+
+      - name: Publish to Registry
+        run: |
+          npx ovsx publish -p $OPEN_VSX_TOKEN *.vsix

.gitignore

@@ -4,6 +4,7 @@
 # Generated files
 /dist/
 out/
+build/
 server/
 node_modules/
 gen/

.vscode/extensions.json

@@ -1,10 +1,12 @@
 {
-  // See http://go.microsoft.com/fwlink/?LinkId=827846 to learn about workspace recommendations.
+  // See https://go.microsoft.com/fwlink/?LinkId=827846 to learn about workspace recommendations.
   // Extension identifier format: ${publisher}.${name}. Example: vscode.csharp
   // List of extensions which should be recommended for users of this workspace.
   "recommendations": [
-    "eamodio.tsl-problem-matcher"
+    "eamodio.tsl-problem-matcher",
+    "dbaeumer.vscode-eslint",
+    "eternalphane.tsfmt-vscode"
   ],
   // List of extensions recommended by VS Code that should not be recommended for users of this workspace.
   "unwantedRecommendations": []
-}
+}

.vscode/launch.json

@@ -8,18 +8,20 @@
       "request": "launch",
       "runtimeExecutable": "${execPath}",
       "args": [
-        "--extensionDevelopmentPath=${workspaceRoot}/dist/vscode-codeql"
+        "--extensionDevelopmentPath=${workspaceRoot}/extensions/ql-vscode",
+        // Add a reference to a workspace to open. Eg-
+        // "${workspaceRoot}/../vscode-codeql-starter/vscode-codeql-starter.code-workspace"
       ],
       "stopOnEntry": false,
       "sourceMaps": true,
       "outFiles": [
-        "${workspaceRoot}/dist/vscode-codeql/out/**/*.js",
-        "${workspaceRoot}/dist/vscode-codeql/node_modules/semmle-bqrs/out/**/*.js",
-        "${workspaceRoot}/dist/vscode-codeql/node_modules/semmle-io/out/**/*.js",
-        "${workspaceRoot}/dist/vscode-codeql/node_modules/semmle-io-node/out/**/*.js",
-        "${workspaceRoot}/dist/vscode-codeql/node_modules/semmle-vscode-utils/out/**/*.js"
+        "${workspaceRoot}/extensions/ql-vscode/out/**/*.js",
       ],
-      "preLaunchTask": "Build"
+      "env": {
+        // change to 'true' debug the IDE or Query servers
+        "IDE_SERVER_JAVA_DEBUG": "false",
+        "QUERY_SERVER_JAVA_DEBUG": "false",
+      }
     },
     {
       "name": "Launch Unit Tests (vscode-codeql)",
@@ -44,7 +46,6 @@
       "port": 9229,
       "stopOnEntry": false,
       "sourceMaps": true,
-      "preLaunchTask": "Build",
       "console": "integratedTerminal",
       "internalConsoleOptions": "neverOpen"
     },
@@ -54,16 +55,14 @@
       "request": "launch",
       "runtimeExecutable": "${execPath}",
       "args": [
-        "--extensionDevelopmentPath=${workspaceRoot}/dist/vscode-codeql",
+        "--extensionDevelopmentPath=${workspaceRoot}/extensions/ql-vscode",
         "--extensionTestsPath=${workspaceRoot}/extensions/ql-vscode/out/vscode-tests/no-workspace/index"
       ],
       "stopOnEntry": false,
       "sourceMaps": true,
       "outFiles": [
-        "${workspaceRoot}/dist/vscode-codeql/out/**/*.js",
-        "${workspaceRoot}/extensions/ql-vscode/out/vscode-tests/**/*.js"
+        "${workspaceRoot}/extensions/ql-vscode/out/**/*.js",
       ],
-      "preLaunchTask": "Build"
     },
     {
       "name": "Launch Integration Tests - Minimal Workspace (vscode-codeql)",
@@ -71,17 +70,34 @@
       "request": "launch",
       "runtimeExecutable": "${execPath}",
       "args": [
-        "--extensionDevelopmentPath=${workspaceRoot}/dist/vscode-codeql",
+        "--extensionDevelopmentPath=${workspaceRoot}/extensions/ql-vscode",
         "--extensionTestsPath=${workspaceRoot}/extensions/ql-vscode/out/vscode-tests/minimal-workspace/index",
         "${workspaceRoot}/extensions/ql-vscode/test/data"
       ],
       "stopOnEntry": false,
       "sourceMaps": true,
       "outFiles": [
-        "${workspaceRoot}/dist/vscode-codeql/out/**/*.js",
-        "${workspaceRoot}/extensions/ql-vscode/out/vscode-tests/**/*.js"
+        "${workspaceRoot}/extensions/ql-vscode/out/**/*.js",
+      ],
+    },
+    {
+      "name": "Launch Integration Tests - With CLI",
+      "type": "extensionHost",
+      "request": "launch",
+      "runtimeExecutable": "${execPath}",
+      "args": [
+        "--extensionDevelopmentPath=${workspaceRoot}/extensions/ql-vscode",
+        "--extensionTestsPath=${workspaceRoot}/extensions/ql-vscode/out/vscode-tests/cli-integration/index",
+        "${workspaceRoot}/extensions/ql-vscode/src/vscode-tests/cli-integration/data",
+        // Add a path to a checked out instance of the codeql repository so the libraries are
+        // available in the workspace for the tests.
+        // "${workspaceRoot}/../codeql"
+      ],
+      "stopOnEntry": false,
+      "sourceMaps": true,
+      "outFiles": [
+        "${workspaceRoot}/extensions/ql-vscode/out/**/*.js",
       ],
-      "preLaunchTask": "Build"
     }
   ]
 }

.vscode/settings.json

@@ -33,6 +33,8 @@
     // This is necessary so that eslint can properly resolve its plugins
     "resolvePluginsRelativeTo": "./extensions/ql-vscode"
   },
-  // Force this to false since this will cause too many changes on each commit
-  "editor.formatOnSave": false
+  "editor.formatOnSave": false,
+  "typescript.preferences.quoteStyle": "single",
+  "javascript.preferences.quoteStyle": "single",
+  "editor.wordWrapColumn": 100
 }

.vscode/tasks.json

@@ -10,7 +10,10 @@
         "kind": "build",
         "isDefault": true
       },
-      "command": "node common/scripts/install-run-rush.js build --verbose",
+      "command": "npm run build",
+      "options": {
+        "cwd": "extensions/ql-vscode/"
+      },
       "presentation": {
         "echo": true,
         "reveal": "always",
@@ -33,64 +36,13 @@
         "$ts-webpack"
       ]
     },
-    {
-      "label": "Rebuild",
-      "type": "shell",
-      "group": "build",
-      "command": "node common/scripts/install-run-rush.js rebuild --verbose",
-      "presentation": {
-        "echo": true,
-        "reveal": "always",
-        "focus": false,
-        "panel": "shared",
-        "showReuseMessage": true,
-        "clear": true
-      },
-      "problemMatcher": [
-        {
-          "owner": "typescript",
-          "fileLocation": "absolute",
-          "pattern": {
-            "regexp": "^\\[gulp-typescript\\] ([^(]+)\\((\\d+|\\d+,\\d+|\\d+,\\d+,\\d+,\\d+)\\): error TS\\d+: (.*)$",
-            "file": 1,
-            "location": 2,
-            "message": 3
-          }
-        }
-      ]
-    },
-    {
-      "label": "Update",
-      "type": "shell",
-      "command": "node common/scripts/install-run-rush.js update",
-      "presentation": {
-        "echo": true,
-        "reveal": "always",
-        "focus": false,
-        "panel": "shared",
-        "showReuseMessage": true,
-        "clear": true
-      },
-      "problemMatcher": []
-    },
-    {
-      "label": "Update (full)",
-      "type": "shell",
-      "command": "node common/scripts/install-run-rush.js update --full",
-      "presentation": {
-        "echo": true,
-        "reveal": "always",
-        "focus": false,
-        "panel": "shared",
-        "showReuseMessage": true,
-        "clear": true
-      },
-      "problemMatcher": []
-    },
     {
       "label": "Format",
       "type": "shell",
-      "command": "node common/scripts/install-run-rush.js format",
+      "command": "npm run format",
+      "options": {
+        "cwd": "extensions/ql-vscode/"
+      },
       "presentation": {
         "echo": true,
         "reveal": "always",
@@ -111,4 +63,4 @@
       "group": "build"
     }
   ]
-}
+}

CONTRIBUTING.md

@@ -25,94 +25,40 @@ Here are a few things you can do that will increase the likelihood of your pull
 * Follow the [style guide][style].
 * Write tests. Tests that don't require the VS Code API are located [here](extensions/ql-vscode/test). Integration tests that do require the VS Code API are located [here](extensions/ql-vscode/src/vscode-tests).
 * Keep your change as focused as possible. If there are multiple changes you would like to make that are not dependent upon each other, consider submitting them as separate pull requests.
-* Write a [good commit message](http://tbaggery.com/2008/04/19/a-note-about-git-commit-messages.html).
+* Write a [good commit message](https://tbaggery.com/2008/04/19/a-note-about-git-commit-messages.html).
 
 ## Setting up a local build
 
-Make sure you have a fairly recent version of vscode (>1.32) and are using nodejs
-version >=v10.13.0. (Tested on v10.15.1 and v10.16.0).
+Make sure you have installed recent versions of vscode (>= v1.52), node (>=12.16), and npm (>= 7.5.2). Earlier versions will probably work, but we no longer test against them.
 
-This repo uses [Rush](https://rushjs.io) to handle package management, building, and other
-operations across multiple projects. See the Rush "[Getting started as a developer](https://rushjs.io/pages/developer/new_developer/)" docs
-for more details.
+### Installing all packages
 
-If you plan on building from the command line, it's easiest if Rush is installed globally:
+From the command line, go to the directory `extensions/ql-vscode` and run
 
 ```shell
-npm install -g @microsoft/rush
+npm install
 ```
 
-To get started, run:
+### Building the extension
+
+From the command line, go to the directory `extensions/ql-vscode` and run
 
 ```shell
-rush update && rush build
+npm run build
+npm run watch
 ```
 
-Note that when you run the `rush` command from the globally installed version, it will examine the
-`rushVersion` property in the repo's `rush.json`, and if it differs from the globally installed
-version, it will download, cache, and run the version of Rush specified in the `rushVersion`
-property.
+Alternatively, you can build the extension within VS Code via `Terminal > Run Build Task...` (or `Ctrl+Shift+B` with the default key bindings). And you can run the watch command via `Terminal > Run Task` and then select `npm watch` from the menu.
 
-A few more things to know about using rush:
+Before running any of the launch commands, be sure to have run the `build` command to ensure that the JavaScript is compiled and the resources are copied to the proper location.
 
-* Avoid running `npm` for any commands that install/link dependencies
-* Instead use the *rush* equivalent: `rush add <package>`, `rush update`, etc.
-* If you plan on only building via VS Code tasks, you don't need Rush installed at all, since those
-tasks run `common/scripts/install-run-rush.js` to bootstrap a locally installed and cached copy of
-Rush.
+We recommend that you keep `npm run watch` running in the backgound and you only need to re-run `npm run build` in the following situations:
 
-### Building
+1. on first checkout
+2. whenever any of the non-TypeScript resources have changed
+3. on any change to files included in the webview
 
-#### Installing all packages (instead of `npm install`)
-
-After updating any `package.json` file, or after checking or pulling a new branch, you need to
-make sure all the right npm packages are installed, which you would normally do via `npm install` in
-a single-project repo. With Rush, you need to do an "update" instead:
-
-##### From VS Code
-
-`Terminal > Run Task... > Update`
-
-##### From the command line
-
-```shell
-rush update
-```
-
-#### Building all projects (instead of `gulp`)
-
-Rush builds all projects in the repo, in dependency order, building multiple projects in parallel
-where possible. By default, the build also packages the extension itself into a .vsix file in the
-`dist` directory. To build:
-
-##### From VS Code
-
-`Terminal > Run Build Task...` (or just `Ctrl+Shift+B` with the default key bindings)
-
-##### From the command line
-
-```shell
-rush build --verbose
-```
-
-#### Forcing a clean build
-
-Rush does a reasonable job of detecting on its own which projects need to be rebuilt, but if you need to
-force a full rebuild of all projects:
-
-##### From VS Code
-
-`Terminal > Run Task... > Rebuild`
-
-##### From the command line
-
-```shell
-rush rebuild --verbose
-```
-
-Note that `rush rebuild` performs a complete rebuild, whereas `rush build` performs an incremental build and in many cases will not need to do anything at all.
-
-### Installing
+### Installing the extension
 
 You can install the `.vsix` file from within VS Code itself, from the Extensions container in the sidebar:
 
@@ -144,24 +90,55 @@ Alternatively, you can run the tests inside of vscode. There are several vscode
 
 ## Releasing (write access required)
 
-1. Double-check the `CHANGELOG.md` contains all desired change comments
-   and has the version to be released with date at the top.
-1. Double-check that the extension `package.json` has the version you intend to release.
-   If you are doing a patch release (as opposed to minor or major version) this should already
-   be correct.
-1. Trigger a release build on Actions by adding a new tag on master of the format `vxx.xx.xx`
+1. Double-check the `CHANGELOG.md` contains all desired change comments and has the version to be released with date at the top.
+    * Go through all recent PRs and make sure they are properly accounted for.
+    * Make sure all changelog entries have links back to their PR(s) if appropriate.
+1. Double-check that the extension `package.json` and `package-lock.json` have the version you intend to release. If you are doing a patch release (as opposed to minor or major version) this should already be correct.
+1. Create a PR for this release:
+    * This PR will contain any missing bits from steps 1 and 2. Most of the time, this will just be updating `CHANGELOG.md` with today's date.
+    * Create a new branch for the release named after the new version. For example: `v1.3.6`
+    * Create a new commit with a message the same as the branch name.
+    * Create a PR for this branch.
+    * Wait for the PR to be merged into `main`
+1. Trigger a release build on Actions by adding a new tag on branch `main` named after the release, as above. Note that when you push to upstream, you will need to fully qualify the ref. A command like this will work:
+
+    ```bash
+    git push upstream refs/tags/v1.3.6
+    ```
+
+    * **IMPORTANT** Make sure you are on the `main` branch and your local checkout is fully updated when you add the tag.
+    * If you accidentally add the tag to the wrong ref, you can just force push it to the right one later.
+
 1. Monitor the status of the release build in the `Release` workflow in the Actions tab.
 1. Download the VSIX from the draft GitHub release at the top of [the releases page](https://github.com/github/vscode-codeql/releases) that is created when the release build finishes.
-1. Optionally unzip the `.vsix` and inspect its `package.json` to make sure the version is what you expect,
+1. Unzip the `.vsix` and inspect its `package.json` to make sure the version is what you expect,
    or look at the source if there's any doubt the right code is being shipped.
-1. Log into the [Visual Studio Marketplace](https://marketplace.visualstudio.com/manage/publishers/github).
-1. Click the `...` menu in the CodeQL row and click **Update**.
-1. Drag the `.vsix` file you downloaded from the GitHub release into the Marketplace and click **Upload**.
-1. Go to the draft GitHub release, click 'Edit', add some summary description, and publish it.
+1. Go to the actions tab of the vscode-codeql repository and select the [Release workflow](https://github.com/github/vscode-codeql/actions?query=workflow%3ARelease).
+    - If there is an authentication failure when publishing, be sure to check that the authentication keys haven't expired. See below.
+1. Approve the deployments of the correct Release workflow. This will automatically publish to Open VSX and VS Code Marketplace.
+1. Go to the draft GitHub release in [the releases tab of the repository](https://github.com/github/vscode-codeql/releases), click 'Edit', add some summary description, and publish it.
 1. Confirm the new release is marked as the latest release at <https://github.com/github/vscode-codeql/releases>.
 1. If documentation changes need to be published, notify documentation team that release has been made.
 1. Review and merge the version bump PR that is automatically created by Actions.
 
+## Secrets and authentication for publishing
+
+Repository administrators, will need to manage the authentication keys for publishing to the VS Code marketplace and Open VSX. Each requires an authentication token. The VS Code marketplace token expires yearly.
+
+To regenerate the Open VSX token:
+
+1. Log in to the [user settings page on Open VSX](https://open-vsx.org/user-settings/namespaces).
+1. Make sure you are a member of the GitHub namespace.
+1. Go to the [Access Tokens](https://open-vsx.org/user-settings/tokens) page and generate a new token.
+1. Update the secret in the `publish-open-vsx` environment in the project settings.
+
+To regenerate the VSCode Marketplace token:
+
+1. Follow the instructions on [getting a PAT for Azure DevOps](https://code.visualstudio.com/api/working-with-extensions/publishing-extension#get-a-personal-access-token).
+1. Update the secret in the `publish-vscode-marketplace` environment in the project settings.
+
+Not that Azure DevOps PATs expire yearly and must be regenerated.
+
 ## Resources
 
 * [How to Contribute to Open Source](https://opensource.guide/how-to-contribute/)

README.md

@@ -4,7 +4,7 @@ This project is an extension for Visual Studio Code that adds rich language supp
 
 The extension is released. You can download it from the [Visual Studio Marketplace](https://marketplace.visualstudio.com/items?itemName=github.vscode-codeql).
 
-To see what has changed in the last few versions of the extension, see the [Changelog](https://github.com/github/vscode-codeql/blob/master/extensions/ql-vscode/CHANGELOG.md).
+To see what has changed in the last few versions of the extension, see the [Changelog](https://github.com/github/vscode-codeql/blob/main/extensions/ql-vscode/CHANGELOG.md).
 
 [![CI status badge](https://github.com/github/vscode-codeql/workflows/Build%20Extension/badge.svg)](https://github.com/github/vscode-codeql/actions?query=workflow%3A%22Build+Extension%22+branch%3Amaster)
 [![VS Marketplace badge](https://vsmarketplacebadge.apphb.com/version/github.vscode-codeql.svg)](https://marketplace.visualstudio.com/items?itemName=github.vscode-codeql)
@@ -13,10 +13,9 @@ To see what has changed in the last few versions of the extension, see the [Chan
 
 * Enables you to use CodeQL to query databases and discover problems in codebases.
 * Shows the flow of data through the results of path queries, which is essential for triaging security results.
-* Provides an easy way to run queries from the large, open source repository of [CodeQL security queries](https://github.com/Semmle/ql).
+* Provides an easy way to run queries from the large, open source repository of [CodeQL security queries](https://github.com/github/codeql).
 * Adds IntelliSense to support you writing and editing your own CodeQL query and library files.
 
-
 ## Project goals and scope
 
 This project will track new feature development in CodeQL and, whenever appropriate, bring that functionality to the Visual Studio Code experience.

build/README.md

@@ -1,12 +0,0 @@
-GitHub Actions Build directory
-===
-
-The point of this directory is to allow us to do a local installation *of* the rush
-tool, since 
- - installing globally is not permitted on github actions
- - installing locally in the root directory of the repo creates `node_modules` there,
-   and rush itself gives error messages since it thinks `node_modules` is not supposed 
-   to exist, since rush is supposed to be managing subproject dependencies.
-
-Running rush from a subdirectory searches parent directories for `rush.json`
-and does the build starting from that file's location.

build/package.json

@@ -1,17 +0,0 @@
-{
-  "name": "build",
-  "version": "1.0.0",
-  "description": "",
-  "main": "index.js",
-  "dependencies": {
-    "@microsoft/rush": "^5.10.3"
-  },
-  "devDependencies": {},
-  "scripts": {
-    "test": "echo \"Error: no test specified\" && exit 1",
-    "build": "rush update && rush build",
-    "build-ci": "rush install && rush build",
-    "build-release": "rush install && rush build --release"
-  },
-  "author": "GitHub"
-}

common/config/LICENSE

@@ -1,28 +0,0 @@
-This directory contains content from https://github.com/microsoft/rushstack,
-used under the MIT license as follows.
-See https://github.com/microsoft/rushstack/blob/master/stack/rush-stack/LICENSE.
-
-@microsoft/rush-stack
-
-Copyright (c) Microsoft Corporation. All rights reserved.
-
-MIT License
-
-Permission is hereby granted, free of charge, to any person obtaining
-a copy of this software and associated documentation files (the
-"Software"), to deal in the Software without restriction, including
-without limitation the rights to use, copy, modify, merge, publish,
-distribute, sublicense, and/or sell copies of the Software, and to
-permit persons to whom the Software is furnished to do so, subject to
-the following conditions:
-
-The above copyright notice and this permission notice shall be
-included in all copies or substantial portions of the Software.
-
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
-EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
-MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
-NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
-LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
-OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
-WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

common/config/rush/.npmrc

@@ -1,12 +0,0 @@
-# Rush uses this file to configure the package registry, regardless of whether the
-# package manager is PNPM, NPM, or Yarn.  Prior to invoking the package manager,
-# Rush will always copy this file to the folder where installation is performed.
-# When NPM is the package manager, Rush works around NPM's processing of
-# undefined environment variables by deleting any lines that reference undefined
-# environment variables.
-#
-# DO NOT SPECIFY AUTHENTICATION CREDENTIALS IN THIS FILE.  It should only be used
-# to configure registry sources.
-
-registry=https://registry.npmjs.org/
-always-auth=false

common/config/rush/command-line.json

@@ -1,32 +0,0 @@
-/**
- * This configuration file defines custom commands for the "rush" command-line.
- * For full documentation, please see https://rushjs.io/pages/configs/command_line_json/
- */
-{
-  "$schema": "https://developer.microsoft.com/json-schemas/rush/v5/command-line.schema.json",
-  "commands": [
-    {
-      "commandKind": "bulk",
-      "name": "format",
-      "summary": "Reformat source code in all projects",
-      "description": "Runs the `format` npm task in each project, if present.",
-      "safeForSimultaneousRushProcesses": false,
-      "enableParallelism": true,
-      "ignoreDependencyOrder": true,
-      "ignoreMissingScript": true,
-      "allowWarningsInSuccessfulBuild": false
-    }
-  ],
-  "parameters": [
-    {
-      "parameterKind": "flag",
-      "longName": "--release",
-      "shortName": "-r",
-      "description": "Perform a release build",
-      "associatedCommands": [
-        "build",
-        "rebuild"
-      ],
-    }
-  ]
-}

common/config/rush/common-versions.json

@@ -1,43 +0,0 @@
-/**
- * This configuration file specifies NPM dependency version selections that affect all projects
- * in a Rush repo.  For full documentation, please see https://rushjs.io
- */
-{
-  "$schema": "https://developer.microsoft.com/json-schemas/rush/v5/common-versions.schema.json",
-
-  /**
-   * A table that specifies a "preferred version" for a dependency package. The "preferred version"
-   * is typically used to hold an indirect dependency back to a specific version, however generally
-   * it can be any SemVer range specifier (e.g. "~1.2.3"), and it will narrow any (compatible)
-   * SemVer range specifier.  See the Rush documentation for details about this feature.
-   */
-  "preferredVersions": {
-
-    /**
-     * When someone asks for "^1.0.0" make sure they get "1.2.3" when working in this repo,
-     * instead of the latest version.
-     */
-    // "some-library": "1.2.3"
-  },
-
-  /**
-   * The "rush check" command can be used to enforce that every project in the repo must specify
-   * the same SemVer range for a given dependency.  However, sometimes exceptions are needed.
-   * The allowedAlternativeVersions table allows you to list other SemVer ranges that will be
-   * accepted by "rush check" for a given dependency.
-   *
-   * IMPORTANT: THIS TABLE IS FOR *ADDITIONAL* VERSION RANGES THAT ARE ALTERNATIVES TO THE
-   * USUAL VERSION (WHICH IS INFERRED BY LOOKING AT ALL PROJECTS IN THE REPO).
-   * This design avoids unnecessary churn in this file.
-   */
-   "allowedAlternativeVersions": {
-
-    /**
-     * For example, allow some projects to use an older TypeScript compiler
-     * (in addition to whatever "usual" version is being used by other projects in the repo):
-     */
-    // "typescript": [
-    //   "~2.4.0"
-    // ]
-  }
-}

common/config/rush/pnpmfile.js

@@ -1,32 +0,0 @@
-"use strict";
-
-/**
- * When using the PNPM package manager, you can use pnpmfile.js to workaround
- * dependencies that have mistakes in their package.json file.  (This feature is
- * functionally similar to Yarn's "resolutions".)
- *
- * For details, see the PNPM documentation:
- * https://pnpm.js.org/docs/en/hooks.html
- *
- * IMPORTANT: SINCE THIS FILE CONTAINS EXECUTABLE CODE, MODIFYING IT IS LIKELY
- * TO INVALIDATE ANY CACHED DEPENDENCY ANALYSIS.  We recommend to run "rush update --full"
- * after any modification to pnpmfile.js.
- *
- */
-module.exports = {
-  hooks: {
-    readPackage
-  }
-};
-
-/**
- * This hook is invoked during installation before a package's dependencies
- * are selected.
- * The `packageJson` parameter is the deserialized package.json
- * contents for the package that is about to be installed.
- * The `context` parameter provides a log() function.
- * The return value is the updated object.
- */
-function readPackage(packageJson, context) {
-  return packageJson;
-}

common/config/rush/version-policies.json

@@ -1,6 +0,0 @@
-/**
- * This is configuration file is used for advanced publishing configurations with Rush.
- * For full documentation, please see https://rushjs.io/pages/configs/version_policies_json/
- */
-
-[]

common/scripts/install-run-rush.js

@@ -1,67 +0,0 @@
-"use strict";
-// Copyright (c) Microsoft Corporation. All rights reserved. Licensed under the MIT license.
-// See the @microsoft/rush package's LICENSE file for license information.
-Object.defineProperty(exports, "__esModule", { value: true });
-// THIS FILE WAS GENERATED BY A TOOL. ANY MANUAL MODIFICATIONS WILL GET OVERWRITTEN WHENEVER RUSH IS UPGRADED.
-//
-// This script is intended for usage in an automated build environment where the Rush command may not have
-// been preinstalled, or may have an unpredictable version.  This script will automatically install the version of Rush
-// specified in the rush.json configuration file (if not already installed), and then pass a command-line to it.
-// An example usage would be:
-//
-//    node common/scripts/install-run-rush.js install
-//
-// For more information, see: https://rushjs.io/pages/maintainer/setup_new_repo/
-const path = require("path");
-const fs = require("fs");
-const install_run_1 = require("./install-run");
-const PACKAGE_NAME = '@microsoft/rush';
-const RUSH_PREVIEW_VERSION = 'RUSH_PREVIEW_VERSION';
-function _getRushVersion() {
-    const rushPreviewVersion = process.env[RUSH_PREVIEW_VERSION];
-    if (rushPreviewVersion !== undefined) {
-        console.log(`Using Rush version from environment variable ${RUSH_PREVIEW_VERSION}=${rushPreviewVersion}`);
-        return rushPreviewVersion;
-    }
-    const rushJsonFolder = install_run_1.findRushJsonFolder();
-    const rushJsonPath = path.join(rushJsonFolder, install_run_1.RUSH_JSON_FILENAME);
-    try {
-        const rushJsonContents = fs.readFileSync(rushJsonPath, 'utf-8');
-        // Use a regular expression to parse out the rushVersion value because rush.json supports comments,
-        // but JSON.parse does not and we don't want to pull in more dependencies than we need to in this script.
-        const rushJsonMatches = rushJsonContents.match(/\"rushVersion\"\s*\:\s*\"([0-9a-zA-Z.+\-]+)\"/);
-        return rushJsonMatches[1];
-    }
-    catch (e) {
-        throw new Error(`Unable to determine the required version of Rush from rush.json (${rushJsonFolder}). ` +
-            'The \'rushVersion\' field is either not assigned in rush.json or was specified ' +
-            'using an unexpected syntax.');
-    }
-}
-function _run() {
-    const [nodePath, /* Ex: /bin/node */ scriptPath, /* /repo/common/scripts/install-run-rush.js */ ...packageBinArgs /* [build, --to, myproject] */] = process.argv;
-    // Detect if this script was directly invoked, or if the install-run-rushx script was invokved to select the
-    // appropriate binary inside the rush package to run
-    const scriptName = path.basename(scriptPath);
-    const bin = scriptName.toLowerCase() === 'install-run-rushx.js' ? 'rushx' : 'rush';
-    if (!nodePath || !scriptPath) {
-        throw new Error('Unexpected exception: could not detect node path or script path');
-    }
-    if (process.argv.length < 3) {
-        console.log(`Usage: ${scriptName} <command> [args...]`);
-        if (scriptName === 'install-run-rush.js') {
-            console.log(`Example: ${scriptName} build --to myproject`);
-        }
-        else {
-            console.log(`Example: ${scriptName} custom-command`);
-        }
-        process.exit(1);
-    }
-    install_run_1.runWithErrorAndStatusCode(() => {
-        const version = _getRushVersion();
-        console.log(`The rush.json configuration requests Rush version ${version}`);
-        return install_run_1.installAndRun(PACKAGE_NAME, version, bin, packageBinArgs);
-    });
-}
-_run();
-//# sourceMappingURL=install-run-rush.js.map

common/scripts/install-run-rushx.js

@@ -1,18 +0,0 @@
-"use strict";
-// Copyright (c) Microsoft Corporation. All rights reserved. Licensed under the MIT license.
-// See the @microsoft/rush package's LICENSE file for license information.
-Object.defineProperty(exports, "__esModule", { value: true });
-// THIS FILE WAS GENERATED BY A TOOL. ANY MANUAL MODIFICATIONS WILL GET OVERWRITTEN WHENEVER RUSH IS UPGRADED.
-//
-// This script is intended for usage in an automated build environment where the Rush command may not have
-// been preinstalled, or may have an unpredictable version.  This script will automatically install the version of Rush
-// specified in the rush.json configuration file (if not already installed), and then pass a command-line to the
-// rushx command.
-//
-// An example usage would be:
-//
-//    node common/scripts/install-run-rushx.js custom-command
-//
-// For more information, see: https://rushjs.io/pages/maintainer/setup_new_repo/
-require("./install-run-rush");
-//# sourceMappingURL=install-run-rushx.js.map

common/scripts/install-run.js

@@ -1,433 +0,0 @@
-"use strict";
-// Copyright (c) Microsoft Corporation. All rights reserved. Licensed under the MIT license.
-// See the @microsoft/rush package's LICENSE file for license information.
-Object.defineProperty(exports, "__esModule", { value: true });
-// THIS FILE WAS GENERATED BY A TOOL. ANY MANUAL MODIFICATIONS WILL GET OVERWRITTEN WHENEVER RUSH IS UPGRADED.
-//
-// This script is intended for usage in an automated build environment where a Node tool may not have
-// been preinstalled, or may have an unpredictable version.  This script will automatically install the specified
-// version of the specified tool (if not already installed), and then pass a command-line to it.
-// An example usage would be:
-//
-//    node common/scripts/install-run.js qrcode@1.2.2 qrcode https://rushjs.io
-//
-// For more information, see: https://rushjs.io/pages/maintainer/setup_new_repo/
-const childProcess = require("child_process");
-const fs = require("fs");
-const os = require("os");
-const path = require("path");
-exports.RUSH_JSON_FILENAME = 'rush.json';
-const RUSH_TEMP_FOLDER_ENV_VARIABLE_NAME = 'RUSH_TEMP_FOLDER';
-const INSTALLED_FLAG_FILENAME = 'installed.flag';
-const NODE_MODULES_FOLDER_NAME = 'node_modules';
-const PACKAGE_JSON_FILENAME = 'package.json';
-/**
- * Parse a package specifier (in the form of name\@version) into name and version parts.
- */
-function _parsePackageSpecifier(rawPackageSpecifier) {
-    rawPackageSpecifier = (rawPackageSpecifier || '').trim();
-    const separatorIndex = rawPackageSpecifier.lastIndexOf('@');
-    let name;
-    let version = undefined;
-    if (separatorIndex === 0) {
-        // The specifier starts with a scope and doesn't have a version specified
-        name = rawPackageSpecifier;
-    }
-    else if (separatorIndex === -1) {
-        // The specifier doesn't have a version
-        name = rawPackageSpecifier;
-    }
-    else {
-        name = rawPackageSpecifier.substring(0, separatorIndex);
-        version = rawPackageSpecifier.substring(separatorIndex + 1);
-    }
-    if (!name) {
-        throw new Error(`Invalid package specifier: ${rawPackageSpecifier}`);
-    }
-    return { name, version };
-}
-/**
- * As a workaround, copyAndTrimNpmrcFile() copies the .npmrc file to the target folder, and also trims
- * unusable lines from the .npmrc file.
- *
- * Why are we trimming the .npmrc lines?  NPM allows environment variables to be specified in
- * the .npmrc file to provide different authentication tokens for different registry.
- * However, if the environment variable is undefined, it expands to an empty string, which
- * produces a valid-looking mapping with an invalid URL that causes an error.  Instead,
- * we'd prefer to skip that line and continue looking in other places such as the user's
- * home directory.
- *
- * IMPORTANT: THIS CODE SHOULD BE KEPT UP TO DATE WITH Utilities._copyNpmrcFile()
- */
-function _copyAndTrimNpmrcFile(sourceNpmrcPath, targetNpmrcPath) {
-    console.log(`Copying ${sourceNpmrcPath} --> ${targetNpmrcPath}`); // Verbose
-    let npmrcFileLines = fs.readFileSync(sourceNpmrcPath).toString().split('\n');
-    npmrcFileLines = npmrcFileLines.map((line) => (line || '').trim());
-    const resultLines = [];
-    // Trim out lines that reference environment variables that aren't defined
-    for (const line of npmrcFileLines) {
-        // This finds environment variable tokens that look like "${VAR_NAME}"
-        const regex = /\$\{([^\}]+)\}/g;
-        const environmentVariables = line.match(regex);
-        let lineShouldBeTrimmed = false;
-        if (environmentVariables) {
-            for (const token of environmentVariables) {
-                // Remove the leading "${" and the trailing "}" from the token
-                const environmentVariableName = token.substring(2, token.length - 1);
-                if (!process.env[environmentVariableName]) {
-                    lineShouldBeTrimmed = true;
-                    break;
-                }
-            }
-        }
-        if (lineShouldBeTrimmed) {
-            // Example output:
-            // "; MISSING ENVIRONMENT VARIABLE: //my-registry.com/npm/:_authToken=${MY_AUTH_TOKEN}"
-            resultLines.push('; MISSING ENVIRONMENT VARIABLE: ' + line);
-        }
-        else {
-            resultLines.push(line);
-        }
-    }
-    fs.writeFileSync(targetNpmrcPath, resultLines.join(os.EOL));
-}
-/**
- * syncNpmrc() copies the .npmrc file to the target folder, and also trims unusable lines from the .npmrc file.
- * If the source .npmrc file not exist, then syncNpmrc() will delete an .npmrc that is found in the target folder.
- *
- * IMPORTANT: THIS CODE SHOULD BE KEPT UP TO DATE WITH Utilities._syncNpmrc()
- */
-function _syncNpmrc(sourceNpmrcFolder, targetNpmrcFolder, useNpmrcPublish) {
-    const sourceNpmrcPath = path.join(sourceNpmrcFolder, !useNpmrcPublish ? '.npmrc' : '.npmrc-publish');
-    const targetNpmrcPath = path.join(targetNpmrcFolder, '.npmrc');
-    try {
-        if (fs.existsSync(sourceNpmrcPath)) {
-            _copyAndTrimNpmrcFile(sourceNpmrcPath, targetNpmrcPath);
-        }
-        else if (fs.existsSync(targetNpmrcPath)) {
-            // If the source .npmrc doesn't exist and there is one in the target, delete the one in the target
-            console.log(`Deleting ${targetNpmrcPath}`); // Verbose
-            fs.unlinkSync(targetNpmrcPath);
-        }
-    }
-    catch (e) {
-        throw new Error(`Error syncing .npmrc file: ${e}`);
-    }
-}
-let _npmPath = undefined;
-/**
- * Get the absolute path to the npm executable
- */
-function getNpmPath() {
-    if (!_npmPath) {
-        try {
-            if (os.platform() === 'win32') {
-                // We're on Windows
-                const whereOutput = childProcess.execSync('where npm', { stdio: [] }).toString();
-                const lines = whereOutput.split(os.EOL).filter((line) => !!line);
-                // take the last result, we are looking for a .cmd command
-                // see https://github.com/microsoft/rushstack/issues/759
-                _npmPath = lines[lines.length - 1];
-            }
-            else {
-                // We aren't on Windows - assume we're on *NIX or Darwin
-                _npmPath = childProcess.execSync('which npm', { stdio: [] }).toString();
-            }
-        }
-        catch (e) {
-            throw new Error(`Unable to determine the path to the NPM tool: ${e}`);
-        }
-        _npmPath = _npmPath.trim();
-        if (!fs.existsSync(_npmPath)) {
-            throw new Error('The NPM executable does not exist');
-        }
-    }
-    return _npmPath;
-}
-exports.getNpmPath = getNpmPath;
-function _ensureFolder(folderPath) {
-    if (!fs.existsSync(folderPath)) {
-        const parentDir = path.dirname(folderPath);
-        _ensureFolder(parentDir);
-        fs.mkdirSync(folderPath);
-    }
-}
-/**
- * Create missing directories under the specified base directory, and return the resolved directory.
- *
- * Does not support "." or ".." path segments.
- * Assumes the baseFolder exists.
- */
-function _ensureAndJoinPath(baseFolder, ...pathSegments) {
-    let joinedPath = baseFolder;
-    try {
-        for (let pathSegment of pathSegments) {
-            pathSegment = pathSegment.replace(/[\\\/]/g, '+');
-            joinedPath = path.join(joinedPath, pathSegment);
-            if (!fs.existsSync(joinedPath)) {
-                fs.mkdirSync(joinedPath);
-            }
-        }
-    }
-    catch (e) {
-        throw new Error(`Error building local installation folder (${path.join(baseFolder, ...pathSegments)}): ${e}`);
-    }
-    return joinedPath;
-}
-function _getRushTempFolder(rushCommonFolder) {
-    const rushTempFolder = process.env[RUSH_TEMP_FOLDER_ENV_VARIABLE_NAME];
-    if (rushTempFolder !== undefined) {
-        _ensureFolder(rushTempFolder);
-        return rushTempFolder;
-    }
-    else {
-        return _ensureAndJoinPath(rushCommonFolder, 'temp');
-    }
-}
-/**
- * Resolve a package specifier to a static version
- */
-function _resolvePackageVersion(rushCommonFolder, { name, version }) {
-    if (!version) {
-        version = '*'; // If no version is specified, use the latest version
-    }
-    if (version.match(/^[a-zA-Z0-9\-\+\.]+$/)) {
-        // If the version contains only characters that we recognize to be used in static version specifiers,
-        // pass the version through
-        return version;
-    }
-    else {
-        // version resolves to
-        try {
-            const rushTempFolder = _getRushTempFolder(rushCommonFolder);
-            const sourceNpmrcFolder = path.join(rushCommonFolder, 'config', 'rush');
-            _syncNpmrc(sourceNpmrcFolder, rushTempFolder);
-            const npmPath = getNpmPath();
-            // This returns something that looks like:
-            //  @microsoft/rush@3.0.0 '3.0.0'
-            //  @microsoft/rush@3.0.1 '3.0.1'
-            //  ...
-            //  @microsoft/rush@3.0.20 '3.0.20'
-            //  <blank line>
-            const npmVersionSpawnResult = childProcess.spawnSync(npmPath, ['view', `${name}@${version}`, 'version', '--no-update-notifier'], {
-                cwd: rushTempFolder,
-                stdio: []
-            });
-            if (npmVersionSpawnResult.status !== 0) {
-                throw new Error(`"npm view" returned error code ${npmVersionSpawnResult.status}`);
-            }
-            const npmViewVersionOutput = npmVersionSpawnResult.stdout.toString();
-            const versionLines = npmViewVersionOutput.split('\n').filter((line) => !!line);
-            const latestVersion = versionLines[versionLines.length - 1];
-            if (!latestVersion) {
-                throw new Error('No versions found for the specified version range.');
-            }
-            const versionMatches = latestVersion.match(/^.+\s\'(.+)\'$/);
-            if (!versionMatches) {
-                throw new Error(`Invalid npm output ${latestVersion}`);
-            }
-            return versionMatches[1];
-        }
-        catch (e) {
-            throw new Error(`Unable to resolve version ${version} of package ${name}: ${e}`);
-        }
-    }
-}
-let _rushJsonFolder;
-/**
- * Find the absolute path to the folder containing rush.json
- */
-function findRushJsonFolder() {
-    if (!_rushJsonFolder) {
-        let basePath = __dirname;
-        let tempPath = __dirname;
-        do {
-            const testRushJsonPath = path.join(basePath, exports.RUSH_JSON_FILENAME);
-            if (fs.existsSync(testRushJsonPath)) {
-                _rushJsonFolder = basePath;
-                break;
-            }
-            else {
-                basePath = tempPath;
-            }
-        } while (basePath !== (tempPath = path.dirname(basePath))); // Exit the loop when we hit the disk root
-        if (!_rushJsonFolder) {
-            throw new Error('Unable to find rush.json.');
-        }
-    }
-    return _rushJsonFolder;
-}
-exports.findRushJsonFolder = findRushJsonFolder;
-/**
- * Detects if the package in the specified directory is installed
- */
-function _isPackageAlreadyInstalled(packageInstallFolder) {
-    try {
-        const flagFilePath = path.join(packageInstallFolder, INSTALLED_FLAG_FILENAME);
-        if (!fs.existsSync(flagFilePath)) {
-            return false;
-        }
-        const fileContents = fs.readFileSync(flagFilePath).toString();
-        return fileContents.trim() === process.version;
-    }
-    catch (e) {
-        return false;
-    }
-}
-/**
- * Removes the following files and directories under the specified folder path:
- *  - installed.flag
- *  -
- *  - node_modules
- */
-function _cleanInstallFolder(rushTempFolder, packageInstallFolder) {
-    try {
-        const flagFile = path.resolve(packageInstallFolder, INSTALLED_FLAG_FILENAME);
-        if (fs.existsSync(flagFile)) {
-            fs.unlinkSync(flagFile);
-        }
-        const packageLockFile = path.resolve(packageInstallFolder, 'package-lock.json');
-        if (fs.existsSync(packageLockFile)) {
-            fs.unlinkSync(packageLockFile);
-        }
-        const nodeModulesFolder = path.resolve(packageInstallFolder, NODE_MODULES_FOLDER_NAME);
-        if (fs.existsSync(nodeModulesFolder)) {
-            const rushRecyclerFolder = _ensureAndJoinPath(rushTempFolder, 'rush-recycler', `install-run-${Date.now().toString()}`);
-            fs.renameSync(nodeModulesFolder, rushRecyclerFolder);
-        }
-    }
-    catch (e) {
-        throw new Error(`Error cleaning the package install folder (${packageInstallFolder}): ${e}`);
-    }
-}
-function _createPackageJson(packageInstallFolder, name, version) {
-    try {
-        const packageJsonContents = {
-            'name': 'ci-rush',
-            'version': '0.0.0',
-            'dependencies': {
-                [name]: version
-            },
-            'description': 'DON\'T WARN',
-            'repository': 'DON\'T WARN',
-            'license': 'MIT'
-        };
-        const packageJsonPath = path.join(packageInstallFolder, PACKAGE_JSON_FILENAME);
-        fs.writeFileSync(packageJsonPath, JSON.stringify(packageJsonContents, undefined, 2));
-    }
-    catch (e) {
-        throw new Error(`Unable to create package.json: ${e}`);
-    }
-}
-/**
- * Run "npm install" in the package install folder.
- */
-function _installPackage(packageInstallFolder, name, version) {
-    try {
-        console.log(`Installing ${name}...`);
-        const npmPath = getNpmPath();
-        const result = childProcess.spawnSync(npmPath, ['install'], {
-            stdio: 'inherit',
-            cwd: packageInstallFolder,
-            env: process.env
-        });
-        if (result.status !== 0) {
-            throw new Error('"npm install" encountered an error');
-        }
-        console.log(`Successfully installed ${name}@${version}`);
-    }
-    catch (e) {
-        throw new Error(`Unable to install package: ${e}`);
-    }
-}
-/**
- * Get the ".bin" path for the package.
- */
-function _getBinPath(packageInstallFolder, binName) {
-    const binFolderPath = path.resolve(packageInstallFolder, NODE_MODULES_FOLDER_NAME, '.bin');
-    const resolvedBinName = (os.platform() === 'win32') ? `${binName}.cmd` : binName;
-    return path.resolve(binFolderPath, resolvedBinName);
-}
-/**
- * Write a flag file to the package's install directory, signifying that the install was successful.
- */
-function _writeFlagFile(packageInstallFolder) {
-    try {
-        const flagFilePath = path.join(packageInstallFolder, INSTALLED_FLAG_FILENAME);
-        fs.writeFileSync(flagFilePath, process.version);
-    }
-    catch (e) {
-        throw new Error(`Unable to create installed.flag file in ${packageInstallFolder}`);
-    }
-}
-function installAndRun(packageName, packageVersion, packageBinName, packageBinArgs) {
-    const rushJsonFolder = findRushJsonFolder();
-    const rushCommonFolder = path.join(rushJsonFolder, 'common');
-    const rushTempFolder = _getRushTempFolder(rushCommonFolder);
-    const packageInstallFolder = _ensureAndJoinPath(rushTempFolder, 'install-run', `${packageName}@${packageVersion}`);
-    if (!_isPackageAlreadyInstalled(packageInstallFolder)) {
-        // The package isn't already installed
-        _cleanInstallFolder(rushTempFolder, packageInstallFolder);
-        const sourceNpmrcFolder = path.join(rushCommonFolder, 'config', 'rush');
-        _syncNpmrc(sourceNpmrcFolder, packageInstallFolder);
-        _createPackageJson(packageInstallFolder, packageName, packageVersion);
-        _installPackage(packageInstallFolder, packageName, packageVersion);
-        _writeFlagFile(packageInstallFolder);
-    }
-    const statusMessage = `Invoking "${packageBinName} ${packageBinArgs.join(' ')}"`;
-    const statusMessageLine = new Array(statusMessage.length + 1).join('-');
-    console.log(os.EOL + statusMessage + os.EOL + statusMessageLine + os.EOL);
-    const binPath = _getBinPath(packageInstallFolder, packageBinName);
-    const result = childProcess.spawnSync(binPath, packageBinArgs, {
-        stdio: 'inherit',
-        cwd: process.cwd(),
-        env: process.env
-    });
-    if (result.status !== null) {
-        return result.status;
-    }
-    else {
-        throw result.error || new Error('An unknown error occurred.');
-    }
-}
-exports.installAndRun = installAndRun;
-function runWithErrorAndStatusCode(fn) {
-    process.exitCode = 1;
-    try {
-        const exitCode = fn();
-        process.exitCode = exitCode;
-    }
-    catch (e) {
-        console.error(os.EOL + os.EOL + e.toString() + os.EOL + os.EOL);
-    }
-}
-exports.runWithErrorAndStatusCode = runWithErrorAndStatusCode;
-function _run() {
-    const [nodePath, /* Ex: /bin/node */ scriptPath, /* /repo/common/scripts/install-run-rush.js */ rawPackageSpecifier, /* qrcode@^1.2.0 */ packageBinName, /* qrcode */ ...packageBinArgs /* [-f, myproject/lib] */] = process.argv;
-    if (!nodePath) {
-        throw new Error('Unexpected exception: could not detect node path');
-    }
-    if (path.basename(scriptPath).toLowerCase() !== 'install-run.js') {
-        // If install-run.js wasn't directly invoked, don't execute the rest of this function. Return control
-        // to the script that (presumably) imported this file
-        return;
-    }
-    if (process.argv.length < 4) {
-        console.log('Usage: install-run.js <package>@<version> <command> [args...]');
-        console.log('Example: install-run.js qrcode@1.2.2 qrcode https://rushjs.io');
-        process.exit(1);
-    }
-    runWithErrorAndStatusCode(() => {
-        const rushJsonFolder = findRushJsonFolder();
-        const rushCommonFolder = _ensureAndJoinPath(rushJsonFolder, 'common');
-        const packageSpecifier = _parsePackageSpecifier(rawPackageSpecifier);
-        const name = packageSpecifier.name;
-        const version = _resolvePackageVersion(rushCommonFolder, packageSpecifier);
-        if (packageSpecifier.version !== version) {
-            console.log(`Resolved to ${name}@${version}`);
-        }
-        return installAndRun(name, version, packageBinName, packageBinArgs);
-    });
-}
-_run();
-//# sourceMappingURL=install-run.js.map

configs/typescript-config/extension.tsconfig.json

@@ -1,8 +0,0 @@
-{
-  "$schema": "http://json.schemastore.org/tsconfig",
-  "extends": "./common.tsconfig.json",
-  "compilerOptions": {
-    "declaration": false,
-    "strict": true
-  }
-}

configs/typescript-config/lib.tsconfig.json

@@ -1,4 +0,0 @@
-{
-  "$schema": "http://json.schemastore.org/tsconfig",
-  "extends": "./common.tsconfig.json"
-}

configs/typescript-config/package.json

@@ -1,18 +0,0 @@
-{
-  "name": "typescript-config",
-  "description": "TypeScript configurations",
-  "author": "GitHub",
-  "private": true,
-  "version": "0.0.1",
-  "publisher": "GitHub",
-  "repository": {
-    "type": "git",
-    "url": "https://github.com/github/vscode-codeql"
-  },
-  "scripts": {
-    "build": "",
-    "format": ""
-  },
-  "devDependencies": {},
-  "dependencies": {}
-}

extensions/ql-vscode/.eslintrc.js

@@ -1,36 +1,35 @@
 module.exports = {
-  parser: '@typescript-eslint/parser',
+  parser: "@typescript-eslint/parser",
   parserOptions: {
     ecmaVersion: 2018,
-    sourceType: 'module',
-    project: ['tsconfig.json', './src/**/tsconfig.json'],
+    sourceType: "module",
+    project: ["tsconfig.json", "./src/**/tsconfig.json", "./gulpfile.ts/tsconfig.json"],
   },
-  plugins: ['@typescript-eslint'],
+  plugins: ["@typescript-eslint"],
   env: {
     node: true,
-    es6: true
+    es6: true,
   },
-  extends: [
-    'eslint:recommended',
-    'plugin:@typescript-eslint/recommended',
-  ],
+  extends: ["eslint:recommended", "plugin:@typescript-eslint/recommended"],
   rules: {
-    '@typescript-eslint/no-use-before-define': 0,
-    '@typescript-eslint/no-unused-vars': ["warn", {
-      "vars": "all",
-      "args": "none",
-      "ignoreRestSiblings": false
-    }],
+    "@typescript-eslint/no-use-before-define": 0,
+    "@typescript-eslint/no-unused-vars": [
+      "warn",
+      {
+        vars: "all",
+        args: "none",
+        ignoreRestSiblings: false,
+      },
+    ],
     "@typescript-eslint/explicit-function-return-type": "off",
     "@typescript-eslint/no-non-null-assertion": "off",
     "@typescript-eslint/no-explicit-any": "off",
-    "prefer-const": ["warn", {"destructuring": "all"}],
-    "indent": "off",
-    "@typescript-eslint/indent": ["error", 2, {
-      "SwitchCase": 1,
-      "FunctionDeclaration": { "body": 1, "parameters": 1 }
-    }],
+    "prefer-const": ["warn", { destructuring: "all" }],
+    indent: "off",
+    "@typescript-eslint/indent": "off",
     "@typescript-eslint/no-throw-literal": "error",
-    "no-useless-escape": 0
+    "no-useless-escape": 0,
+    semi: 2,
+    quotes: ["warn", "single"]
   },
 };

extensions/ql-vscode/CHANGELOG.md

@@ -1,5 +1,192 @@
 # CodeQL for Visual Studio Code: Changelog
 
+## 1.4.8 - 05 May 2021
+
+- Copy version information to the clipboard when a user clicks the CodeQL section of the status bar. [#845](https://github.com/github/vscode-codeql/pull/845)
+- Ensure changes in directories that contain tests will be properly updated in the test explorer. [#846](https://github.com/github/vscode-codeql/pull/846)
+- Remind users to choose a language when downloading a database from LGTM. [#852](https://github.com/github/vscode-codeql/pull/852)
+
+## 1.4.7 - 23 April 2021
+
+- Fix a bug that prevented the results view from being loaded. [#842](https://github.com/github/vscode-codeql/pull/842)
+
+## 1.4.6 - 21 April 2021
+
+- Avoid showing an error popup when running a query with `@kind table` metadata. [#814](https://github.com/github/vscode-codeql/pull/814)
+- Add an option to jump from a .qlref file to the .ql file it references. [#815](https://github.com/github/vscode-codeql/pull/815)
+- Avoid opening the results panel when a database is deleted. [#831](https://github.com/github/vscode-codeql/pull/831)
+- Forward all query metadata to the CLI when interpreting results. [#838](https://github.com/github/vscode-codeql/pull/838)
+
+## 1.4.5 - 22 March 2021
+
+- Avoid showing an error popup when user runs a query without `@kind` metadata. [#801](https://github.com/github/vscode-codeql/pull/801)
+- Fix running of tests when the `ms-python` extension is installed. [#803](https://github.com/github/vscode-codeql/pull/803)
+
+## 1.4.4 - 19 March 2021
+
+- Introduce evaluator options for saving intermediate results to the disk cache (`codeQL.runningQueries.saveCache`) and for limiting the size of this cache (`codeQL.runningQueries.cacheSize`). [#778](https://github.com/github/vscode-codeql/pull/778)
+- Respect the `codeQL.runningQueries.numberOfThreads` setting when creating SARIF files during result interpretation. [#771](https://github.com/github/vscode-codeql/pull/771)
+- Allow using raw LGTM project slugs for fetching LGTM databases. [#769](https://github.com/github/vscode-codeql/pull/769)
+- Better error messages when BQRS interpretation fails to produce SARIF. [#770](https://github.com/github/vscode-codeql/pull/770)
+- Implement sorting of the query history view by name, date, and results count. [#777](https://github.com/github/vscode-codeql/pull/777)
+- Add a configuration option to pass additional arguments to the CLI when running tests. [#785](https://github.com/github/vscode-codeql/pull/785)
+- Introduce option to view query results as CSV. [#784](https://github.com/github/vscode-codeql/pull/784)
+- Add some snippets for commonly used QL statements. [#782](https://github.com/github/vscode-codeql/pull/782)
+- More descriptive error messages on QL test failures. [#788](https://github.com/github/vscode-codeql/pull/788)
+
+## 1.4.3 - 22 February 2021
+
+- Avoid displaying an error when removing orphaned databases and the storage folder does not exist. [#748](https://github.com/github/vscode-codeql/pull/748)
+- Add better error messages when AST Viewer is unable to create an AST. [#753](https://github.com/github/vscode-codeql/pull/753)
+- Cache AST viewing operations so that subsequent calls to view the AST of a single file will be extremely fast. [#753](https://github.com/github/vscode-codeql/pull/753)
+- Ensure CodeQL version in status bar updates correctly when version changes. [#754](https://github.com/github/vscode-codeql/pull/754)
+- Avoid deleting the quick query file when it is re-opened. [#747](https://github.com/github/vscode-codeql/pull/747)
+
+## 1.4.2 - 2 February 2021
+
+- Add a status bar item for the CodeQL CLI to show the current version. [#741](https://github.com/github/vscode-codeql/pull/741)
+- Fix version constraint for flagging CLI support of non-destructive updates. [#744](https://github.com/github/vscode-codeql/pull/744)
+- Add a _More Information_ button in the telemetry popup that opens the [telemetry documentation](https://codeql.github.com/docs/codeql-for-visual-studio-code/about-telemetry-in-codeql-for-visual-studio-code) in a browser tab. [#742](https://github.com/github/vscode-codeql/pull/742)
+
+## 1.4.1 - 29 January 2021
+
+- Reword the telemetry modal dialog box. [#738](https://github.com/github/vscode-codeql/pull/738)
+
+## 1.4.0 - 29 January 2021
+
+- Fix bug where databases are not reregistered when the query server restarts. [#734](https://github.com/github/vscode-codeql/pull/734)
+- Fix bug where upgrade requests were erroneously being marked as failed. [#734](https://github.com/github/vscode-codeql/pull/734)
+- On a strictly opt-in basis, collect anonymized usage data from the VS Code extension, helping improve CodeQL's usability and performance. See the [telemetry documentation](https://codeql.github.com/docs/codeql-for-visual-studio-code/about-telemetry-in-codeql-for-visual-studio-code) for more information on exactly what data is collected and what it is used for. [#611](https://github.com/github/vscode-codeql/pull/611)
+
+## 1.3.10 - 20 January 2021
+
+- Include the full stack in error log messages to help with debugging. [#726](https://github.com/github/vscode-codeql/pull/726)
+
+## 1.3.9 - 12 January 2021
+
+- No changes visible to end users.
+
+## 1.3.8 - 17 December 2020
+
+- Ensure databases are unlocked when removing them from the workspace. This will ensure that after a database is removed from VS Code, queries can be run on it from the command line without restarting the IDE. Requires CodeQL CLI 2.4.1 or later. [#681](https://github.com/github/vscode-codeql/pull/681)
+- Fix bug when removing databases where sometimes the source folder would not also be removed from the workspace or the database files would not be deleted from the workspace storage location. [#692](https://github.com/github/vscode-codeql/pull/692)
+- Query results with no string representation will now be displayed with placeholder text in query results. Previously, they were omitted. [#694](https://github.com/github/vscode-codeql/pull/694)
+- Add a label for the language of a database in the databases view. This will only take effect for new databases created with the CodeQL CLI v2.4.1 or later. [#697](https://github.com/github/vscode-codeql/pull/697)
+- Add clearer error message when running a query using a missing or invalid qlpack. [#702](https://github.com/github/vscode-codeql/pull/702)
+- Add clearer error message when trying to run a command from the query history view if no item in the history is selected. [#702](https://github.com/github/vscode-codeql/pull/702)
+- Fix a bug where it is not possible to download some database archives. This fix specifically addresses large archives and archives whose central directories do not align with file headers. [#700](https://github.com/github/vscode-codeql/pull/700)
+- Avoid error dialogs when QL test discovery or database cleanup encounters a missing directory. [#706](https://github.com/github/vscode-codeql/pull/706)
+- Add descriptive text and a link in the results view. [#711](https://github.com/github/vscode-codeql/pull/711)
+- Fix the _Set Label_ command in the query history view. [#710](https://github.com/github/vscode-codeql/pull/710)
+- Add the _CodeQL: View AST_ command to the right-click context menu when a source file in a database source archive is open in the editor. [#712](https://github.com/github/vscode-codeql/pull/712)
+
+## 1.3.7 - 24 November 2020
+
+- Editors opened by navigating from the results view are no longer opened in _preview mode_. Now they are opened as a persistent editor. [#630](https://github.com/github/vscode-codeql/pull/630)
+- When comparing the results of a failed QL test run and the `.expected` file does not exist, an empty `.expected` file is created and compared against the `.actual` file. [#669](https://github.com/github/vscode-codeql/pull/669)
+- Alter structure of the _Test Explorer_ tree. It now follows the structure of the filesystem instead of the QL Packs. [#624](https://github.com/github/vscode-codeql/pull/624)
+- Alter structure of the _Test Explorer_ tree. It now follows the structure of the filesystem instead of the QL Packs. [#624](https://github.com/github/vscode-codeql/pull/624)
+- Add more structured output for tests. [#626](https://github.com/github/vscode-codeql/pull/626)
+- Whenever the extension restarts, orphaned databases will be cleaned up. These are databases whose files are located inside of the extension's storage area, but are not imported into the workspace.
+- After renaming a database, the database list is re-sorted. [#685](https://github.com/github/vscode-codeql/pull/685)
+- Add a `codeQl.resultsDisplay.pageSize` setting to configure the number of results displayed in a single results view page. Increase the default page size from 100 to 200. [#686](https://github.com/github/vscode-codeql/pull/686)
+- Update the AST Viewer to include edge labels (if available) in addition to the target node labels. So far, only C/C++ databases take advantage of this change. [#688](https://github.com/github/vscode-codeql/pull/688)
+
+## 1.3.6 - 4 November 2020
+
+- Fix URI encoding for databases that were created with special characters in their paths. [#648](https://github.com/github/vscode-codeql/pull/648)
+- Disable CodeQL Test commands from the command palette [#667](https://github.com/github/vscode-codeql/pull/667)
+- Fix display of booleans in results view. [#657](https://github.com/github/vscode-codeql/pull/657)
+- Avoid recursive selection changes in AST Viewer. [#668](https://github.com/github/vscode-codeql/pull/668)
+
+## 1.3.5 - 27 October 2020
+
+- Fix a bug where archived source folders for databases were not showing any contents.
+- Fix URI encoding for databases that were created with special characters in their paths.
+
+## 1.3.4 - 22 October 2020
+
+- Add friendly welcome message when the databases view is empty.
+- Add open query, open results, and remove query commands in the query history view title bar.
+- The maximum number of simultaneous queries launchable by the `CodeQL: Run Queries in Selected Files` command is now configurable by changing the `codeQL.runningQueries.maxQueries` setting.
+- Allow simultaneously run queries to be canceled in a single-click.
+- Prevent multiple upgrade dialogs from appearing when running simultaneous queries on upgradeable databases.
+- Fix sorting of results. Some pages of results would have the wrong sort order and columns.
+- Remember previous sort order when reloading query results.
+- Fix proper escaping of backslashes in SARIF message strings.
+- Allow setting `codeQL.runningQueries.numberOfThreads` and `codeQL.runningTests.numberOfThreads` to 0, (which is interpreted as 'use one thread per core on the machine').
+- Clear the problems view of all CodeQL query results when a database is removed.
+- Add a `View DIL` command on query history items. This opens a text editor containing the Datalog Intermediary Language representation of the compiled query.
+- Remove feature flag for the AST Viewer. For more information on how to use the AST Viewer, [see the documentation](https://help.semmle.com/codeql/codeql-for-vscode/procedures/exploring-the-structure-of-your-source-code.html).
+- The `codeQL.runningTests.numberOfThreads` setting is now used correctly when running tests.
+- Alter structure of the _Test Explorer_ tree. It now follows the structure of the filesystem instead of the qlpacks.
+- Ensure output of CodeQL test runs includes compilation error messages and test failure messages.
+
+## 1.3.3 - 16 September 2020
+
+- Fix display of raw results entities with label but no url.
+- Fix bug where sort order is forgotten when changing raw results page.
+- Avoid showing a location link in results view when a result item has an empty location.
+
+## 1.3.2 - 12 August 2020
+
+- Fix error with choosing qlpack search path.
+- Fix pagination when there are no results.
+- Suppress database downloaded from URL message when action canceled.
+- Fix QL test discovery to avoid showing duplicate tests in the test explorer.
+- Enable pagination of query results
+- Add experimental AST Viewer for Go and C++. To enable, add `"codeQL.experimentalAstViewer": true` to the user settings file.
+
+## 1.3.1 - 7 July 2020
+
+- Fix unzipping of large files.
+- Ensure compare order is consistent when selecting two queries to compare. The first query selected is always the _from_ query and the query selected later is always the _to_ query.
+- Ensure added databases have zipped source locations for databases added as archives or downloaded from the internet.
+- Fix bug where it is not possible to add databases starting with `db-*`.
+- Change styling of pagination section of the results page.
+- Fix display of query text for stored quick queries.
+
+## 1.3.0 - 22 June 2020
+
+- Report error when selecting invalid database.
+- Add descriptive message for database archive import failure.
+- Respect VS Code's i18n locale setting when formatting dates and sorting strings.
+- Allow the opening of large SARIF files externally from VS Code.
+- Add new 'CodeQL: Compare Query' command that shows the differences between two queries.
+- Allow multiple items in the query history view to be removed in one operation.
+- Allow multiple items in the databases view to be removed in one operation.
+- Allow multiple items in the databases view to be upgraded in one operation.
+- Allow multiple items in the databases view to have their external folders opened.
+- Allow all selected queries to be run in one command from the file explorer.
+
+## 1.2.2 - 8 June 2020
+
+- Fix auto-indentation rules.
+- Add ability to download platform-specific releases of the CodeQL CLI if they are available.
+- Fix handling of downloading prerelease versions of the CodeQL CLI.
+- Add pagination for displaying non-interpreted results.
+
+## 1.2.1 - 29 May 2020
+
+- Better formatting and autoindentation when adding QLDoc comments to `.ql` and `.qll` files.
+- Allow for more flexibility when opening a database in the workspace. A user can now choose the actual database folder, or the nested `db-*` folder.
+- Add query history menu command for viewing corresponding SARIF file.
+- Add ability for users to download databases directly from LGTM.com.
+
+## 1.2.0 - 19 May 2020
+
+- Enable 'Go to Definition' and 'Go to References' on source archive
+  files in CodeQL databases. This is handled by a CodeQL query.
+- Fix adding database archive files on Windows.
+- Enable adding remote and local database archive files from the
+  command palette.
+
+## 1.1.5 - 15 May 2020
+
+- Links in results are no longer underlined and monospaced.
+- Add the ability to choose a database either from an archive, a folder, or from the internet.
+- New icons for commands on the databases view.
+
 ## 1.1.4 - 13 May 2020
 
 - Add the ability to download and install databases archives from the internet.

extensions/ql-vscode/README.md

@@ -1,31 +1,31 @@
 # CodeQL extension for Visual Studio Code
 
-This project is an extension for Visual Studio Code that adds rich language support for [CodeQL](https://help.semmle.com/codeql) and allows you to easily find problems in codebases. In particular, the extension:
+This project is an extension for Visual Studio Code that adds rich language support for [CodeQL](https://codeql.github.com/docs/) and allows you to easily find problems in codebases. In particular, the extension:
 
-* Enables you to use CodeQL to query databases generated from source code.
-* Shows the flow of data through the results of path queries, which is essential for triaging security results.
-* Provides an easy way to run queries from the large, open source repository of [CodeQL security queries](https://github.com/Semmle/ql).
-* Adds IntelliSense to support you writing and editing your own CodeQL query and library files.
+- Enables you to use CodeQL to query databases generated from source code.
+- Shows the flow of data through the results of path queries, which is essential for triaging security results.
+- Provides an easy way to run queries from the large, open source repository of [CodeQL security queries](https://github.com/github/codeql).
+- Adds IntelliSense to support you writing and editing your own CodeQL query and library files.
 
-To see what has changed in the last few versions of the extension, see the [Changelog](https://github.com/github/vscode-codeql/blob/master/extensions/ql-vscode/CHANGELOG.md).
+To see what has changed in the last few versions of the extension, see the [Changelog](https://github.com/github/vscode-codeql/blob/main/extensions/ql-vscode/CHANGELOG.md).
 
 ## Quick start overview
 
 The information in this `README` file describes the quickest way to start using CodeQL.
-For information about other configurations, see the separate [CodeQL help](https://help.semmle.com/codeql/codeql-for-vscode.html).
+For information about other configurations, see the separate [CodeQL help](https://codeql.github.com/docs/codeql-for-visual-studio-code/).
 
-**Quick start: Installing and configuring the extension**
+### Quick start: Installing and configuring the extension
 
 1. [Install the extension](#installing-the-extension).
 1. [Check access to the CodeQL CLI](#checking-access-to-the-codeql-cli).
 1. [Clone the CodeQL starter workspace](#cloning-the-codeql-starter-workspace).
 
-**Quick start: Using CodeQL**
+### Quick start: Using CodeQL
 
 1. [Import a database from LGTM](#importing-a-database-from-lgtm).
 1. [Run a query](#running-a-query).
 
------
+---
 
 ## Quick start: Installing and configuring the extension
 
@@ -40,19 +40,34 @@ The CodeQL extension requires a minimum of Visual Studio Code 1.39. Older versio
 
 ### Checking access to the CodeQL CLI
 
-The extension uses the [CodeQL CLI](https://help.semmle.com/codeql/codeql-cli.html) to compile and run queries. The extension automatically manages access to the CLI for you by default (recommended). To check for updates to the CodeQL CLI, you can use the **CodeQL: Check for CLI Updates** command.
+The extension uses the [CodeQL CLI](https://codeql.github.com/docs/codeql-cli/) to compile and run queries. The extension automatically manages access to the CLI for you by default (recommended). To check for updates to the CodeQL CLI, you can use the **CodeQL: Check for CLI Updates** command.
 
-If you want to override the default behavior and use a CodeQL CLI that's already on your machine, see [Configuring access to the CodeQL CLI](https://help.semmle.com/codeql/codeql-for-vscode/procedures/setting-up.html#configuring-access-to-the-codeql-cli).
+If you want to override the default behavior and use a CodeQL CLI that's already on your machine, see [Configuring access to the CodeQL CLI](https://codeql.github.com/docs/codeql-for-visual-studio-code/setting-up-codeql-in-visual-studio-code/#configuring-access-to-the-codeql-cli).
 
 If you have any difficulty with CodeQL CLI access, see the **CodeQL Extension Log** in the **Output** view for any error messages.
 
 ### Cloning the CodeQL starter workspace
 
 When you're working with CodeQL, you need access to the standard CodeQL libraries and queries.
-Initially, we recommend that you clone and use the ready-to-use starter workspace, https://github.com/github/vscode-codeql-starter/.
+Initially, we recommend that you clone and use the ready-to-use [starter workspace](https://github.com/github/vscode-codeql-starter/).
 This includes libraries and queries for the main supported languages, with folders set up ready for your custom queries. After cloning the workspace (use `git clone --recursive`), you can use it in the same way as any other VS Code workspace—with the added advantage that you can easily update the CodeQL libraries.
 
-For information about configuring an existing workspace for CodeQL, [see the documentation](https://help.semmle.com/codeql/codeql-for-vscode/procedures/setting-up.html#updating-an-existing-workspace-for-codeql).
+For information about configuring an existing workspace for CodeQL, [see the documentation](https://codeql.github.com/docs/codeql-for-visual-studio-code/setting-up-codeql-in-visual-studio-code/#updating-an-existing-workspace-for-codeql).
+
+## Upgrading CodeQL standard libraries
+
+You can easily keep up-to-date with the latest changes to the [CodeQL standard libraries](https://github.com/github/codeql).
+
+If you're using the [CodeQL starter workspace](https://github.com/github/vscode-codeql-starter/), you can pull in the latest standard libraries by running:
+
+```shell
+git pull
+git submodule update --recursive
+```
+
+in the starter workspace directory.
+
+If you're using your own clone of the CodeQL standard libraries, you can do a `git pull` from where you have the libraries checked out.
 
 ## Quick start: Using CodeQL
 
@@ -60,18 +75,15 @@ You can find all the commands contributed by the extension in the Command Palett
 
 ### Importing a database from LGTM
 
-While you can use the [CodeQL CLI to create your own databases](https://help.semmle.com/codeql/codeql-cli/procedures/create-codeql-database.html), the simplest way to start is by downloading a database from LGTM.com.
+While you can use the [CodeQL CLI to create your own databases](https://codeql.github.com/docs/codeql-cli/creating-codeql-databases/), the simplest way to start is by downloading a database from LGTM.com.
 
-1. Log in to LGTM.com.
-1. Find a project you're interested in and display the **Integrations** tab (for example, [Apache Kafka](https://lgtm.com/projects/g/apache/kafka/ci/)).
-1. Scroll to the **CodeQL databases for local analysis** section at the bottom of the page.
-1. Download databases for the languages that you want to explore.
-1. Unzip the databases.
-1. For each database that you want to import:
-    1. In the VS Code sidebar, go to **CodeQL** > **Databases** and click **+**.
-    1. Browse to the unzipped database folder (the parent folder that contains `db-<language>` and `src`) and select **Choose database** to add it.
-
-When the import is complete, each CodeQL database is displayed in the CodeQL sidebar under **Databases**.
+1. Open [LGTM.com](https://lgtm.com/#explore) in your browser.
+1. Search for a project you're interested in, for example [Apache Kafka](https://lgtm.com/projects/g/apache/kafka).
+1. Copy the link to that project, for example `https://lgtm.com/projects/g/apache/kafka`.
+1. In VS Code, open the Command Palette and choose the **CodeQL: Download Database from LGTM** command.
+1. Paste the link you copied earlier.
+1. Select the language for the database you want to download (only required if the project has databases for multiple languages).
+1. Once the CodeQL database has been imported, it is displayed in the Databases view.
 
 ### Running a query
 
@@ -79,7 +91,7 @@ The instructions below assume that you're using the CodeQL starter workspace, or
 
 1. Expand the `ql` folder and locate a query to run. The standard queries are grouped by target language and then type, for example: `ql/java/ql/src/Likely Bugs`.
 1. Open a query (`.ql`) file.
-3. Right-click in the query window and select **CodeQL: Run Query**. Alternatively, open the Command Palette (**Ctrl+Shift+P** or **Cmd+Shift+P**), type `Run Query`, then select **CodeQL: Run Query**.
+1. Right-click in the query window and select **CodeQL: Run Query**. Alternatively, open the Command Palette (**Ctrl+Shift+P** or **Cmd+Shift+P**), type `Run Query`, then select **CodeQL: Run Query**.
 
 The CodeQL extension runs the query on the current database using the CLI and reports progress in the bottom right corner of the application.
 When the results are ready, they're displayed in the CodeQL Query Results view. Use the dropdown menu to choose between different forms of result output.
@@ -88,13 +100,17 @@ If there are any problems running a query, a notification is displayed in the bo
 
 ## What next?
 
-For more information about the CodeQL extension, [see the documentation](https://help.semmle.com/codeql/codeql-for-vscode.html). Otherwise, you could:
+For more information about the CodeQL extension, [see the documentation](https://codeql.github.com/docs/codeql-for-visual-studio-code/). Otherwise, you could:
 
-* [Create a database for a different codebase](https://help.semmle.com/codeql/codeql-cli/procedures/create-codeql-database.html).
-* [Try out variant analysis](https://help.semmle.com/QL/learn-ql/ql-training.html).
-* [Learn more about CodeQL](https://help.semmle.com/QL/learn-ql/).
-* [Read how security researchers use CodeQL to find CVEs](https://securitylab.github.com/research).
+- [Create a database for a different codebase](https://codeql.github.com/docs/codeql-cli/creating-codeql-databases/).
+- [Try out variant analysis](https://help.semmle.com/QL/learn-ql/ql-training.html).
+- [Learn more about CodeQL](https://codeql.github.com/docs/).
+- [Read how security researchers use CodeQL to find CVEs](https://securitylab.github.com/research).
 
 ## License
 
 The CodeQL extension for Visual Studio Code is [licensed](LICENSE.md) under the MIT License. The version of CodeQL used by the CodeQL extension is subject to the [GitHub CodeQL Terms & Conditions](https://securitylab.github.com/tools/codeql/license).
+
+## Data and Telemetry
+
+If you specifically opt-in to permit GitHub to do so, GitHub will collect usage data and metrics for the purposes of helping the core developers to improve the CodeQL extension for VS Code. This data will not be shared with any parties outside of GitHub. IP addresses and installation IDs will be retained for a maximum of 30 days. Anonymous data will be retained for a maximum of 180 days. For more information about telemetry, [see the documentation](https://codeql.github.com/docs/codeql-for-visual-studio-code/about-telemetry-in-codeql-for-visual-studio-code).

extensions/ql-vscode/gulpfile.js/index.js

@@ -1,19 +0,0 @@
-'use strict';
-
-require('ts-node').register({});
-const gulp = require('gulp');
-const {
-  compileTypeScript,
-  watchTypeScript,
-  packageExtension,
-  compileTextMateGrammar,
-  copyTestData,
-  copyViewCss
-} = require('build-tasks');
-const { compileView } = require('./webpack');
-
-exports.buildWithoutPackage = gulp.parallel(compileTypeScript, compileTextMateGrammar, compileView, copyTestData, copyViewCss);
-exports.compileTextMateGrammar = compileTextMateGrammar;
-exports.default = gulp.series(exports.buildWithoutPackage, packageExtension);
-exports.watchTypeScript = watchTypeScript;
-exports.compileTypeScript = compileTypeScript;

extensions/ql-vscode/gulpfile.js/webpack.ts

@@ -1,28 +0,0 @@
-import * as webpack from 'webpack';
-import { config } from './webpack.config';
-
-export function compileView(cb: (err?: Error) => void) {
-  webpack(config).run((error, stats) => {
-    if (error) {
-      cb(error);
-    }
-    console.log(stats.toString({
-      errorDetails: true,
-      colors: true,
-      assets: false,
-      builtAt: false,
-      version: false,
-      hash: false,
-      entrypoints: false,
-      timings: false,
-      modules: false,
-      errors: true
-    }));
-    if (stats.hasErrors()) {
-      cb(new Error('Compilation errors detected.'));
-      return;
-    }
-
-    cb();
-  });
-}

extensions/ql-vscode/gulpfile.ts/appInsights.ts

@@ -0,0 +1,16 @@
+import * as gulp from 'gulp';
+import * as replace from 'gulp-replace';
+
+/** Inject the application insights key into the telemetry file */
+export function injectAppInsightsKey() {
+  if (!process.env.APP_INSIGHTS_KEY) {
+    // noop
+    console.log('APP_INSIGHTS_KEY environment variable is not set. So, cannot inject it into the application.');
+    return Promise.resolve();
+  }
+
+  // replace the key
+  return gulp.src(['out/telemetry.js'])
+    .pipe(replace(/REPLACE-APP-INSIGHTS-KEY/, process.env.APP_INSIGHTS_KEY))
+    .pipe(gulp.dest('out/'));
+}

extensions/ql-vscode/gulpfile.ts/deploy.ts

@@ -0,0 +1,73 @@
+import * as fs from 'fs-extra';
+import * as jsonc from 'jsonc-parser';
+import * as path from 'path';
+
+export interface DeployedPackage {
+  distPath: string;
+  name: string;
+  version: string;
+}
+
+const packageFiles = [
+  '.vscodeignore',
+  'CHANGELOG.md',
+  'README.md',
+  'language-configuration.json',
+  'snippets.json',
+  'media',
+  'node_modules',
+  'out'
+];
+
+async function copyPackage(sourcePath: string, destPath: string): Promise<void> {
+  for (const file of packageFiles) {
+    console.log(`copying ${path.resolve(sourcePath, file)} to ${path.resolve(destPath, file)}`);
+    await fs.copy(path.resolve(sourcePath, file), path.resolve(destPath, file));
+  }
+}
+
+export async function deployPackage(packageJsonPath: string): Promise<DeployedPackage> {
+  try {
+    const packageJson: any = jsonc.parse(await fs.readFile(packageJsonPath, 'utf8'));
+
+    // Default to development build; use flag --release to indicate release build.
+    const isDevBuild = !process.argv.includes('--release');
+    const distDir = path.join(__dirname, '../../../dist');
+    await fs.mkdirs(distDir);
+
+    if (isDevBuild) {
+      // NOTE: rootPackage.name had better not have any regex metacharacters
+      const oldDevBuildPattern = new RegExp('^' + packageJson.name + '[^/]+-dev[0-9.]+\\.vsix$');
+      // Dev package filenames are of the form
+      //    vscode-codeql-0.0.1-dev.2019.9.27.19.55.20.vsix
+      (await fs.readdir(distDir)).filter(name => name.match(oldDevBuildPattern)).map(build => {
+        console.log(`Deleting old dev build ${build}...`);
+        fs.unlinkSync(path.join(distDir, build));
+      });
+      const now = new Date();
+      packageJson.version = packageJson.version +
+        `-dev.${now.getUTCFullYear()}.${now.getUTCMonth() + 1}.${now.getUTCDate()}` +
+        `.${now.getUTCHours()}.${now.getUTCMinutes()}.${now.getUTCSeconds()}`;
+    }
+
+    const distPath = path.join(distDir, packageJson.name);
+    await fs.remove(distPath);
+    await fs.mkdirs(distPath);
+
+    await fs.writeFile(path.join(distPath, 'package.json'), JSON.stringify(packageJson, null, 2));
+
+    const sourcePath = path.join(__dirname, '..');
+    console.log(`Copying package '${packageJson.name}' and its dependencies to '${distPath}'...`);
+    await copyPackage(sourcePath, distPath);
+
+    return {
+      distPath: distPath,
+      name: packageJson.name,
+      version: packageJson.version
+    };
+  }
+  catch (e) {
+    console.error(e);
+    throw e;
+  }
+}

extensions/ql-vscode/gulpfile.ts/index.ts

@@ -0,0 +1,15 @@
+import * as gulp from 'gulp';
+import { compileTypeScript, watchTypeScript, copyViewCss } from './typescript';
+import { compileTextMateGrammar } from './textmate';
+import { copyTestData } from './tests';
+import { compileView } from './webpack';
+import { packageExtension } from './package';
+import { injectAppInsightsKey } from './appInsights';
+
+export const buildWithoutPackage =
+  gulp.parallel(
+    compileTypeScript, compileTextMateGrammar, compileView, copyTestData, copyViewCss
+  );
+
+export { compileTextMateGrammar, watchTypeScript, compileTypeScript, copyTestData, injectAppInsightsKey };
+export default gulp.series(buildWithoutPackage, injectAppInsightsKey, packageExtension);

extensions/ql-vscode/gulpfile.ts/package.ts

@@ -1,6 +1,6 @@
 import * as path from 'path';
 import { deployPackage } from './deploy';
-import * as child_process from 'child-process-promise';
+import * as childProcess from 'child-process-promise';
 
 export async function packageExtension(): Promise<void> {
   const deployedPackage = await deployPackage(path.resolve('package.json'));
@@ -9,7 +9,7 @@ export async function packageExtension(): Promise<void> {
     'package',
     '--out', path.resolve(deployedPackage.distPath, '..', `${deployedPackage.name}-${deployedPackage.version}.vsix`)
   ];
-  const proc = child_process.spawn('vsce', args, {
+  const proc = childProcess.spawn('./node_modules/.bin/vsce', args, {
     cwd: deployedPackage.distPath
   });
   proc.childProcess.stdout!.on('data', (data) => {

extensions/ql-vscode/gulpfile.ts/tests.ts

@@ -0,0 +1,17 @@
+import * as gulp from 'gulp';
+
+export function copyTestData() {
+  copyNoWorkspaceData();
+  copyCliIntegrationData();
+  return Promise.resolve();
+}
+
+function copyNoWorkspaceData() {
+  return gulp.src('src/vscode-tests/no-workspace/data/**/*')
+    .pipe(gulp.dest('out/vscode-tests/no-workspace/data'));
+}
+
+function copyCliIntegrationData() {
+  return gulp.src('src/vscode-tests/cli-integration/data/**/*')
+    .pipe(gulp.dest('out/vscode-tests/cli-integration/data'));
+}

extensions/ql-vscode/gulpfile.ts/textmate.ts

@@ -1,5 +1,5 @@
 import * as gulp from 'gulp';
-import * as js_yaml from 'js-yaml';
+import * as jsYaml from 'js-yaml';
 import * as through from 'through2';
 import * as PluginError from 'plugin-error';
 import * as Vinyl from 'vinyl';
@@ -13,9 +13,10 @@ import * as Vinyl from 'vinyl';
  */
 function replaceReferencesWithStrings(value: string, replacements: Map<string, string>): string {
   let result = value;
+  // eslint-disable-next-line no-constant-condition
   while (true) {
     const original = result;
-    for (const key of replacements.keys()) {
+    for (const key of Array.from(replacements.keys())) {
       result = result.replace(`(?#${key})`, `(?:${replacements.get(key)})`);
     }
     if (result === original) {
@@ -32,7 +33,7 @@ function replaceReferencesWithStrings(value: string, replacements: Map<string, s
  */
 function gatherMacros(yaml: any): Map<string, string> {
   const macros = new Map<string, string>();
-  for (var key in yaml.macros) {
+  for (const key in yaml.macros) {
     macros.set(key, yaml.macros[key]);
   }
 
@@ -55,7 +56,7 @@ function getNodeMatchText(rule: any): string {
   else if (rule.patterns !== undefined) {
     const patterns: string[] = [];
     // For a list of patterns, use the disjunction of those patterns.
-    for (var patternIndex in rule.patterns) {
+    for (const patternIndex in rule.patterns) {
       const pattern = rule.patterns[patternIndex];
       if (pattern.include !== null) {
         patterns.push('(?' + pattern.include + ')');
@@ -65,7 +66,7 @@ function getNodeMatchText(rule: any): string {
     return '(?:' + patterns.join('|') + ')';
   }
   else {
-    return ''
+    return '';
   }
 }
 
@@ -78,7 +79,7 @@ function getNodeMatchText(rule: any): string {
  */
 function gatherMatchTextForRules(yaml: any): Map<string, string> {
   const replacements = new Map<string, string>();
-  for (var key in yaml.repository) {
+  for (const key in yaml.repository) {
     const node = yaml.repository[key];
     replacements.set(key, getNodeMatchText(node));
   }
@@ -106,7 +107,7 @@ function visitAllRulesInFile(yaml: any, action: (rule: any) => void) {
  * @param action Callback to invoke on each rule.
  */
 function visitAllRulesInRuleMap(ruleMap: any, action: (rule: any) => void) {
-  for (var key in ruleMap) {
+  for (const key in ruleMap) {
     const rule = ruleMap[key];
     if ((typeof rule) === 'object') {
       action(rule);
@@ -124,7 +125,7 @@ function visitAllRulesInRuleMap(ruleMap: any, action: (rule: any) => void) {
  * @param action The transformation to make on each match pattern.
  */
 function visitAllMatchesInRule(rule: any, action: (match: any) => any) {
-  for (var key in rule) {
+  for (const key in rule) {
     switch (key) {
       case 'begin':
       case 'end':
@@ -184,10 +185,10 @@ function transformFile(yaml: any) {
   visitAllRulesInFile(yaml, (rule) => {
     visitAllMatchesInRule(rule, (match) => {
       if ((typeof match) === 'object') {
-        for (var key in match) {
+        for (const key in match) {
           return macros.get(key)!.replace('(?#)', `(?:${match[key]})`);
         }
-        throw new Error("No key in macro map.")
+        throw new Error('No key in macro map.');
       }
       else {
         return match;
@@ -225,7 +226,7 @@ export function transpileTextMateGrammar() {
     else if (file.isBuffer()) {
       const buf: Buffer = file.contents;
       const yamlText: string = buf.toString('utf8');
-      const jsonData: any = js_yaml.safeLoad(yamlText);
+      const jsonData: any = jsYaml.safeLoad(yamlText);
       transformFile(jsonData);
 
       file.contents = Buffer.from(JSON.stringify(jsonData, null, 2), 'utf8');

extensions/ql-vscode/gulpfile.ts/tsconfig.json

@@ -1,15 +1,14 @@
 {
+  "$schema": "https://json.schemastore.org/tsconfig",
   "compilerOptions": {
     "declaration": true,
+    "strict": true,
     "module": "commonjs",
     "target": "es2017",
-    "outDir": "out",
-    "lib": [
-      "es6"
-    ],
+    "lib": ["es6"],
     "moduleResolution": "node",
     "sourceMap": true,
-    "rootDir": "../../src",
+    "rootDir": ".",
     "strictNullChecks": true,
     "noFallthroughCasesInSwitch": true,
     "preserveWatchOutput": true,
@@ -19,12 +18,5 @@
     "noUnusedLocals": true,
     "noUnusedParameters": true
   },
-  "include": [
-    "../../src/**/*.ts"
-  ],
-  "exclude": [
-    "../../node_modules",
-    "../../test",
-    "../../**/view"
-  ]
+  "include": ["*.ts"]
 }

extensions/ql-vscode/gulpfile.ts/typescript.ts

@@ -0,0 +1,42 @@
+import * as colors from 'ansi-colors';
+import * as gulp from 'gulp';
+import * as sourcemaps from 'gulp-sourcemaps';
+import * as ts from 'gulp-typescript';
+
+function goodReporter(): ts.reporter.Reporter {
+  return {
+    error: (error, typescript) => {
+      if (error.tsFile) {
+        console.log('[' + colors.gray('gulp-typescript') + '] ' + colors.red(error.fullFilename
+          + '(' + (error.startPosition!.line + 1) + ',' + error.startPosition!.character + '): ')
+          + 'error TS' + error.diagnostic.code + ': ' + typescript.flattenDiagnosticMessageText(error.diagnostic.messageText, '\n'));
+      }
+      else {
+        console.log(error.message);
+      }
+    },
+  };
+}
+
+const tsProject = ts.createProject('tsconfig.json');
+
+export function compileTypeScript() {
+  return tsProject.src()
+    .pipe(sourcemaps.init())
+    .pipe(tsProject(goodReporter()))
+    .pipe(sourcemaps.write('.', {
+      includeContent: false,
+      sourceRoot: '.',
+    }))
+    .pipe(gulp.dest('out'));
+}
+
+export function watchTypeScript() {
+  gulp.watch('src/**/*.ts', compileTypeScript);
+}
+
+/** Copy CSS files for the results view into the output directory. */
+export function copyViewCss() {
+  return gulp.src('src/view/*.css')
+    .pipe(gulp.dest('out'));
+}

extensions/ql-vscode/gulpfile.ts/webpack.config.ts

@@ -4,21 +4,28 @@ import * as webpack from 'webpack';
 export const config: webpack.Configuration = {
   mode: 'development',
   entry: {
-    resultsView: './src/view/results.tsx'
+    resultsView: './src/view/results.tsx',
+    compareView: './src/compare/view/Compare.tsx',
   },
   output: {
     path: path.resolve(__dirname, '..', 'out'),
-    filename: "[name].js"
+    filename: '[name].js'
   },
-  devtool: "inline-source-map",
+  devtool: 'inline-source-map',
   resolve: {
-    extensions: ['.js', '.ts', '.tsx', '.json']
+    extensions: ['.js', '.ts', '.tsx', '.json'],
+    fallback: {
+      path: require.resolve('path-browserify')
+    }
   },
   module: {
     rules: [
       {
         test: /\.(ts|tsx)$/,
         loader: 'ts-loader',
+        options: {
+          configFile: 'src/view/tsconfig.json',
+        }
       },
       {
         test: /\.less$/,

extensions/ql-vscode/gulpfile.ts/webpack.ts

@@ -0,0 +1,30 @@
+import * as webpack from 'webpack';
+import { config } from './webpack.config';
+
+export function compileView(cb: (err?: Error) => void) {
+  webpack(config).run((error, stats) => {
+    if (error) {
+      cb(error);
+    }
+    if (stats) {
+      console.log(stats.toString({
+        errorDetails: true,
+        colors: true,
+        assets: false,
+        builtAt: false,
+        version: false,
+        hash: false,
+        entrypoints: false,
+        timings: false,
+        modules: false,
+        errors: true
+      }));
+      if (stats.hasErrors()) {
+        cb(new Error('Compilation errors detected.'));
+        return;
+      }
+    }
+
+    cb();
+  });
+}

extensions/ql-vscode/language-configuration.json

@@ -1,72 +1,34 @@
 {
-    "comments": {
-        // symbol used for single line comment. Remove this entry if your language does not support line comments
-        "lineComment": "//",
-        // symbols used for start and end a block comment. Remove this entry if your language does not support block comments
-        "blockComment": [
-            "/*",
-            "*/"
-        ]
-    },
-    // symbols used as brackets
-    "brackets": [
-        [
-            "{",
-            "}"
-        ],
-        [
-            "[",
-            "]"
-        ],
-        [
-            "(",
-            ")"
-        ]
-    ],
-    // symbols that are auto closed when typing
-    "autoClosingPairs": [
-        [
-            "{",
-            "}"
-        ],
-        [
-            "[",
-            "]"
-        ],
-        [
-            "(",
-            ")"
-        ],
-        [
-            "\"",
-            "\""
-        ],
-        [
-            "'",
-            "'"
-        ]
-    ],
-    // symbols that that can be used to surround a selection
-    "surroundingPairs": [
-        [
-            "{",
-            "}"
-        ],
-        [
-            "[",
-            "]"
-        ],
-        [
-            "(",
-            ")"
-        ],
-        [
-            "\"",
-            "\""
-        ],
-        [
-            "'",
-            "'"
-        ]
-    ]
-}
+  "comments": {
+    "lineComment": "//",
+    "blockComment": ["/*", "*/"]
+  },
+  "brackets": [
+    ["{", "}"],
+    ["[", "]"],
+    ["(", ")"]
+  ],
+  "autoClosingPairs": [
+    { "open": "{", "close": "}" },
+    { "open": "[", "close": "]" },
+    { "open": "(", "close": ")" },
+    { "open": "'", "close": "'", "notIn": ["string", "comment"] },
+    { "open": "\"", "close": "\"", "notIn": ["string"] },
+    { "open": "/**", "close": " */", "notIn": ["string"] }
+  ],
+  "autoCloseBefore": ";:.=}])> \n\t",
+  "surroundingPairs": [
+    ["{", "}"],
+    ["[", "]"],
+    ["(", ")"],
+    ["'", "'"],
+    ["\"", "\""]
+  ],
+  "folding": {
+    "markers": {
+      "start": "^\\s*//\\s*#?region\\b",
+      "end": "^\\s*//\\s*#?endregion\\b"
+    }
+  },
+  "wordPattern": "(-?\\d*\\.\\d\\w*)|([^\\~\\!\\@\\#\\%\\^\\&\\*\\(\\)\\-\\=\\+\\[\\{\\]\\}\\\\\\|\\;\\:\\'\\\"\\.\\<\\>\\/\\?\\s]+)"
+}

extensions/ql-vscode/media/dark/archive-plus.svg

@@ -0,0 +1,5 @@
+<svg width="16" height="16" viewBox="0 0 16 16" fill="none" xmlns="http://www.w3.org/2000/svg">
+<path fill-rule="evenodd" clip-rule="evenodd" d="M14.5 1H1.5L1 1.5V4.5L1.5 5H2V13.5L2.5 14H13.5L14 13.5V5H14.5L15 4.5V1.5L14.5 1ZM13.5 4H2.5H2V2H14V4H13.5ZM3 13V5H13V13H3ZM11 7H5V8H11V7Z" fill="#C5C5C5"/>
+<line y2="12" x2="8" y1="12" x1="16" stroke-width="1" stroke="green" fill="none"/>
+<line y2="8" x2="12" y1="16" x1="12" stroke-width="1" stroke="green" fill="none"/>
+</svg>

extensions/ql-vscode/media/dark/clear-all.svg

@@ -0,0 +1,7 @@
+<svg width="16" height="16" viewBox="0 0 16 16" fill="none" xmlns="http://www.w3.org/2000/svg">
+<path d="M10 12.6L10.7 13.3L12.3 11.7L13.9 13.3L14.7 12.6L13 11L14.7 9.40005L13.9 8.60005L12.3 10.3L10.7 8.60005L10 9.40005L11.6 11L10 12.6Z" fill="#C5C5C5"/>
+<path d="M1 4L15 4L15 3L1 3L1 4Z" fill="#C5C5C5"/>
+<path d="M1 7L15 7L15 6L1 6L1 7Z" fill="#C5C5C5"/>
+<path d="M9 9.5L9 9L1 9L1 10L9 10L9 9.5Z" fill="#C5C5C5"/>
+<path d="M9 13L9 12.5L9 12L1 12L1 13L9 13Z" fill="#C5C5C5"/>
+</svg>

extensions/ql-vscode/media/dark/cloud-download.svg

@@ -0,0 +1,3 @@
+<svg width="16" height="16" viewBox="0 0 16 16" fill="none" xmlns="http://www.w3.org/2000/svg">
+<path fill-rule="evenodd" clip-rule="evenodd" d="M11.9565 6H12.0064C12.8004 6 13.5618 6.31607 14.1232 6.87868C14.6846 7.44129 15 8.20435 15 9C15 9.79565 14.6846 10.5587 14.1232 11.1213C13.5618 11.6839 12.8004 12 12.0064 12V11C12.5357 11 13.0434 10.7893 13.4176 10.4142C13.7919 10.0391 14.0021 9.53044 14.0021 9C14.0021 8.46957 13.7919 7.96086 13.4176 7.58579C13.0434 7.21072 12.5357 7 12.0064 7H11.0924L10.9687 6.143C10.8938 5.60541 10.6456 5.10711 10.2618 4.72407C9.87801 4.34103 9.37977 4.09427 8.84303 4.02143C8.30629 3.94859 7.76051 4.05365 7.2889 4.3206C6.81729 4.58754 6.44573 5.00173 6.23087 5.5L5.89759 6.262L5.08933 6.073C4.90382 6.02699 4.71364 6.0025 4.52255 6C3.86093 6 3.22641 6.2634 2.75858 6.73224C2.29075 7.20108 2.02792 7.83696 2.02792 8.5C2.02792 9.16304 2.29075 9.79893 2.75858 10.2678C3.22641 10.7366 3.86093 11 4.52255 11H5.02148V12H4.52255C4.02745 12.0043 3.5371 11.903 3.08403 11.7029C2.63096 11.5028 2.22553 11.2084 1.89461 10.8394C1.5637 10.4703 1.31488 10.0349 1.16465 9.56211C1.01442 9.08932 0.966217 8.58992 1.02324 8.09704C1.08026 7.60416 1.24121 7.12906 1.4954 6.70326C1.74959 6.27745 2.09121 5.91068 2.49762 5.62727C2.90402 5.34385 3.36591 5.15027 3.85264 5.05937C4.33938 4.96847 4.83984 4.98232 5.32083 5.1C5.6241 4.40501 6.14511 3.82799 6.80496 3.45635C7.4648 3.08472 8.22753 2.9387 8.9776 3.04044C9.72768 3.14217 10.4242 3.4861 10.9618 4.02014C11.4993 4.55418 11.8485 5.24923 11.9565 6ZM6.70719 11.1214L8.0212 12.4354V7H9.01506V12.3992L10.2929 11.1214L11 11.8285L8.85356 13.9749H8.14645L6.00008 11.8285L6.70719 11.1214Z" fill="#C5C5C5"/>
+</svg>

extensions/ql-vscode/media/dark/edit.svg

@@ -0,0 +1,3 @@
+<svg width="16" height="16" viewBox="0 0 16 16" fill="none" xmlns="http://www.w3.org/2000/svg">
+<path d="M13.23 1H11.77L3.52002 9.25L3.35999 9.46997L1 13.59L2.41003 15L6.53003 12.64L6.75 12.48L15 4.22998V2.77002L13.23 1ZM2.41003 13.59L3.92004 10.59L5.37 12.04L2.41003 13.59ZM6.23999 11.53L4.46997 9.76001L12.47 1.76001L14.24 3.53003L6.23999 11.53Z" fill="#C5C5C5"/>
+</svg>

extensions/ql-vscode/media/dark/folder-opened-plus.svg

@@ -0,0 +1,5 @@
+<svg width="16" height="16" viewBox="0 0 16 16" fill="none" xmlns="http://www.w3.org/2000/svg">
+<path d="M0.5 14H12.5L12.98 13.63L15.61 6.63L15.13 6H13V3.5L12.5 3H6.70996L5.84998 2.15002L5.5 2H0.5L0 2.5V13.5L0.5 14ZM1 3H5.29004L6.15002 3.84998L6.5 4H12V6H8.5L8.15002 6.15002L7.29004 7H2.5L2.03003 7.33997L1.03003 10.42L1 3ZM12.13 13H1.18994L2.85999 8H7.5L7.84998 7.84998L8.70996 7H14.5L12.13 13Z" fill="#C5C5C5"/>
+<line y2="12" x2="8" y1="12" x1="16" stroke-width="1" stroke="green" fill="none"/>
+<line y2="8" x2="12" y1="16" x1="12" stroke-width="1" stroke="green" fill="none"/>
+</svg>

extensions/ql-vscode/media/dark/lgtm-plus.svg

@@ -0,0 +1,5 @@
+<svg xmlns="http://www.w3.org/2000/svg" width="32" height="32" viewBox="0 0 32 32" fill="none">
+  <path d="M16.010 6.49c-3.885 0-7.167 0.906-9.328 2.813-0.063-0.12-0.109-0.219-0.188-0.339-0.224-0.365-0.438-0.776-1.104-1.188-0.411-0.26-0.87-0.438-1.349-0.516-0.208-0.021-0.422-0.021-0.63 0l0.135-0.016c-1.214 0-1.922 0.724-2.385 1.354-0.458 0.625-0.755 1.328-0.948 2.099-0.38 1.542-0.385 3.536 1.083 5.026 0.766 0.781 1.667 1.151 2.484 1.37 0.156 0.042 0.297 0.052 0.448 0.083 0.531 2.521 2.104 4.656 4.208 5.839v0.005c1.24 0.693 2.417 1.010 3.297 1.349 1.234 0.479 2.536 1 4.052 1.135l0.078 0.005h0.198c1.745 0 3.063-0.703 4.203-1.141 0.875-0.333 2.052-0.641 3.302-1.344 0.578-0.323 1.115-0.719 1.594-1.172 1.318-1.234 2.229-2.839 2.625-4.599 1.115-0.182 2.141-0.719 2.922-1.536 1.464-1.484 1.458-3.479 1.078-5.021-0.193-0.771-0.49-1.474-0.948-2.099-0.458-0.63-1.172-1.354-2.385-1.354l0.135 0.016c-0.208-0.021-0.422-0.021-0.63 0-0.479 0.078-0.938 0.255-1.344 0.516-0.667 0.411-0.88 0.823-1.104 1.182-0.073 0.12-0.12 0.219-0.188 0.333-2.156-1.901-5.432-2.802-9.313-2.802zM16.042 8.313c4.745 0 8.016 1.422 9.411 3.964 0.839-0.323 1.453-2.521 2.146-2.948 0.563-0.344 0.885-0.26 0.885-0.26 1.271 0 2.578 3.729 0.953 5.38-0.859 0.875-2.443 1.12-3.229 1.057-0.063 2.542-1.542 4.833-3.5 5.932-1 0.563-2.068 0.854-3.063 1.234-1.229 0.469-2.38 1.016-3.547 1.016h-0.125c-1.161-0.099-2.318-0.542-3.547-1.016-0.995-0.38-2.068-0.682-3.063-1.24-1.948-1.099-3.427-3.391-3.49-5.927-0.781 0.068-2.385-0.177-3.245-1.057-1.625-1.651-0.318-5.38 0.948-5.38 0 0 0.328-0.083 0.885 0.26 0.698 0.427 1.318 2.646 2.161 2.953 1.391-2.547 4.667-3.969 9.417-3.969zM10.875 11.422c-2.276-0.042-4.146 1.792-4.146 4.068 0 2.281 1.87 4.115 4.146 4.073 5.328-0.099 5.328-8.047 0-8.141zM21.208 11.422c-5.427 0-5.427 8.141 0 8.141s5.427-8.141 0-8.141zM11.453 13.708c2.349 0.063 2.349 3.552 0 3.615-1.182 0-2.042-1.115-1.75-2.255 0.318 0.771 1.469 0.547 1.464-0.292 0-0.406-0.318-0.745-0.729-0.76 0.302-0.203 0.656-0.313 1.016-0.307zM20.641 13.708c2.344 0.063 2.344 3.552 0 3.615-1.182 0-2.047-1.115-1.755-2.255 0.229 0.552 0.979 0.641 1.328 0.146 0.344-0.49 0.010-1.167-0.589-1.193 0.297-0.208 0.651-0.313 1.016-0.313zM15.359 19.906c-0.318 0.026-0.5 0.193-0.5 0.635 0 0.281 0.182 0.484 0.5 0.484 0.229 0 0.266-0.323 0.047-0.375-0.031-0.005-0.172-0.057-0.172-0.182 0-0.12 0-0.167 0.24-0.198 0.104-0.016 0.156-0.141 0.125-0.24s-0.125-0.135-0.24-0.125zM16.724 19.906c-0.115-0.005-0.208 0.026-0.24 0.125s0.021 0.224 0.125 0.24c0.24 0.031 0.24 0.078 0.24 0.198 0 0.125-0.141 0.177-0.172 0.182-0.219 0.052-0.182 0.375 0.042 0.375 0.323 0 0.51-0.203 0.51-0.484 0-0.443-0.188-0.609-0.505-0.635z" fill="#C5C5C5"/>
+  <line y2="24" x2="16" y1="26" x1="32" stroke-width="2" stroke="green" fill="none"/>
+  <line y2="16" x2="24" y1="32" x1="24" stroke-width="1" stroke="green" fill="none"/>
+</svg>

extensions/ql-vscode/media/dark/preview.svg

@@ -0,0 +1,3 @@
+<svg width="16" height="16" viewBox="0 0 16 16" fill="none" xmlns="http://www.w3.org/2000/svg">
+<path fill-rule="evenodd" clip-rule="evenodd" d="M2 2H14L15 3V13L14 14H2L1 13V3L2 2ZM2 13H14V3H2V13ZM13 4H3V7H13V4ZM12 6H4V5H12V6ZM9 12H13V8H9V12ZM10 9H12V11H10V9ZM7 8H3V9H7V8ZM3 11H7V12H3V11Z" fill="#C5C5C5"/>
+</svg>

extensions/ql-vscode/media/dark/sort-num.svg

@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="iso-8859-1"?>
+<!-- Generator: Adobe Illustrator 19.0.0, SVG Export Plug-In . SVG Version: 6.00 Build 0)  -->
+<svg version="1.1" id="Capa_1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" x="0px" y="0px" fill="none"
+	 viewBox="0 0 432 432" style="enable-background:new 0 0 432 432;" xml:space="preserve">
+<g>
+	<g>
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extensions/ql-vscode/package.json

@@ -4,7 +4,7 @@
   "description": "CodeQL for Visual Studio Code",
   "author": "GitHub",
   "private": true,
-  "version": "1.1.4",
+  "version": "1.4.8",
   "publisher": "GitHub",
   "license": "MIT",
   "icon": "media/VS-marketplace-CodeQL-icon.png",
@@ -13,7 +13,7 @@
     "url": "https://github.com/github/vscode-codeql"
   },
   "engines": {
-    "vscode": "^1.39.0"
+    "vscode": "^1.43.0"
   },
   "categories": [
     "Programming Languages"
@@ -25,11 +25,20 @@
     "onLanguage:ql",
     "onView:codeQLDatabases",
     "onView:codeQLQueryHistory",
+    "onView:codeQLAstViewer",
     "onView:test-explorer",
     "onCommand:codeQL.checkForUpdatesToCLI",
-    "onCommand:codeQL.chooseDatabase",
+    "onCommand:codeQLDatabases.chooseDatabaseFolder",
+    "onCommand:codeQLDatabases.chooseDatabaseArchive",
+    "onCommand:codeQLDatabases.chooseDatabaseInternet",
+    "onCommand:codeQLDatabases.chooseDatabaseLgtm",
     "onCommand:codeQL.setCurrentDatabase",
-    "onCommand:codeQL.downloadDatabase",
+    "onCommand:codeQL.viewAst",
+    "onCommand:codeQL.openReferencedFile",
+    "onCommand:codeQL.chooseDatabaseFolder",
+    "onCommand:codeQL.chooseDatabaseArchive",
+    "onCommand:codeQL.chooseDatabaseInternet",
+    "onCommand:codeQL.chooseDatabaseLgtm",
     "onCommand:codeQLDatabases.chooseDatabase",
     "onCommand:codeQLDatabases.setCurrentDatabase",
     "onCommand:codeQL.quickQuery",
@@ -98,6 +107,12 @@
         "path": "./out/syntaxes/dbscheme.tmLanguage.json"
       }
     ],
+    "snippets": [
+      {
+        "language": "ql",
+        "path": "./snippets.json"
+      }
+    ],
     "configuration": {
       "type": "object",
       "title": "CodeQL",
@@ -106,15 +121,30 @@
           "scope": "machine",
           "type": "string",
           "default": "",
-          "description": "Path to the CodeQL executable that should be used by the CodeQL extension. The executable is named `codeql` on Linux/Mac and `codeql.exe` on Windows. This overrides all other CodeQL CLI settings."
+          "description": "Path to the CodeQL executable that should be used by the CodeQL extension. The executable is named `codeql` on Linux/Mac and `codeql.exe` on Windows. If empty, the extension will look for a CodeQL executable on your shell PATH, or if CodeQL is not on your PATH, download and manage its own CodeQL executable."
         },
         "codeQL.runningQueries.numberOfThreads": {
           "type": "integer",
           "default": 1,
-          "minimum": 1,
+          "minimum": 0,
           "maximum": 1024,
           "description": "Number of threads for running queries."
         },
+        "codeQL.runningQueries.saveCache": {
+          "type": "boolean",
+          "default": false,
+          "scope": "window",
+          "description": "Aggressively save intermediate results to the disk cache. This may speed up subsequent queries if they are similar. Be aware that using this option will greatly increase disk usage and initial evaluation time."
+        },
+        "codeQL.runningQueries.cacheSize": {
+          "type": [
+            "integer",
+            "null"
+          ],
+          "default": null,
+          "minimum": 1024,
+          "description": "Maximum size of the disk cache (in MB). Leave blank to allow the evaluator to automatically adjust the size of the disk cache based on the size of the codebase and the complexity of the queries being executed."
+        },
         "codeQL.runningQueries.timeout": {
           "type": [
             "integer",
@@ -144,18 +174,46 @@
           "default": false,
           "description": "Enable automatically saving a modified query file when running a query."
         },
+        "codeQL.runningQueries.maxQueries": {
+          "type": "integer",
+          "default": 20,
+          "description": "Max number of simultaneous queries to run using the 'CodeQL: Run Queries' command."
+        },
+        "codeQL.resultsDisplay.pageSize": {
+          "type": "integer",
+          "default": 200,
+          "description": "Max number of query results to display per page in the results view."
+        },
         "codeQL.queryHistory.format": {
           "type": "string",
-          "default": "[%t] %q on %d - %s",
-          "description": "Default string for how to label query history items. %t is the time of the query, %q is the query name, %d is the database name, and %s is a status string."
+          "default": "%q on %d - %s, %r result count [%t]",
+          "description": "Default string for how to label query history items. %t is the time of the query, %q is the query name, %d is the database name, %r is the number of results, and %s is a status string."
+        },
+        "codeQL.runningTests.additionalTestArguments": {
+          "scope": "machine",
+          "type": "array",
+          "default": [],
+          "markdownDescription": "Additional command line arguments to pass to the CLI when [running tests](https://codeql.github.com/docs/codeql-cli/manual/test-run/). This setting should be an array of strings, each containing an argument to be passed."
         },
         "codeQL.runningTests.numberOfThreads": {
           "scope": "window",
           "type": "integer",
           "default": 1,
-          "minimum": 1,
+          "minimum": 0,
           "maximum": 1024,
           "description": "Number of threads for running CodeQL tests."
+        },
+        "codeQL.telemetry.enableTelemetry": {
+          "type": "boolean",
+          "default": false,
+          "scope": "application",
+          "markdownDescription": "Specifies whether to send CodeQL usage telemetry. This setting AND the global `#telemetry.enableTelemetry#` setting must be checked for telemetry to be sent to GitHub. For more information, see the [telemetry documentation](https://codeql.github.com/docs/codeql-for-visual-studio-code/about-telemetry-in-codeql-for-visual-studio-code)"
+        },
+        "codeQL.telemetry.logTelemetry": {
+          "type": "boolean",
+          "default": false,
+          "scope": "application",
+          "description": "Specifies whether or not to write telemetry events to the extension log."
         }
       }
     },
@@ -164,26 +222,74 @@
         "command": "codeQL.runQuery",
         "title": "CodeQL: Run Query"
       },
+      {
+        "command": "codeQL.runQueries",
+        "title": "CodeQL: Run Queries in Selected Files"
+      },
       {
         "command": "codeQL.quickEval",
         "title": "CodeQL: Quick Evaluation"
       },
+      {
+        "command": "codeQL.openReferencedFile",
+        "title": "CodeQL: Open Referenced File"
+      },
       {
         "command": "codeQL.quickQuery",
         "title": "CodeQL: Quick Query"
       },
       {
-        "command": "codeQL.chooseDatabase",
-        "title": "CodeQL: Choose Database",
+        "command": "codeQL.openDocumentation",
+        "title": "CodeQL: Open Documentation"
+      },
+      {
+        "command": "codeQL.copyVersion",
+        "title": "CodeQL: Copy Version Information"
+      },
+      {
+        "command": "codeQLDatabases.chooseDatabaseFolder",
+        "title": "Choose Database from Folder",
         "icon": {
-          "light": "media/light/plus.svg",
-          "dark": "media/dark/plus.svg"
+          "light": "media/light/folder-opened-plus.svg",
+          "dark": "media/dark/folder-opened-plus.svg"
+        }
+      },
+      {
+        "command": "codeQLDatabases.removeOrphanedDatabases",
+        "title": "Delete unused databases"
+      },
+      {
+        "command": "codeQLDatabases.chooseDatabaseArchive",
+        "title": "Choose Database from Archive",
+        "icon": {
+          "light": "media/light/archive-plus.svg",
+          "dark": "media/dark/archive-plus.svg"
+        }
+      },
+      {
+        "command": "codeQLDatabases.chooseDatabaseInternet",
+        "title": "Download Database",
+        "icon": {
+          "light": "media/light/cloud-download.svg",
+          "dark": "media/dark/cloud-download.svg"
+        }
+      },
+      {
+        "command": "codeQLDatabases.chooseDatabaseLgtm",
+        "title": "Download from LGTM",
+        "icon": {
+          "light": "media/light/lgtm-plus.svg",
+          "dark": "media/dark/lgtm-plus.svg"
         }
       },
       {
         "command": "codeQL.setCurrentDatabase",
         "title": "CodeQL: Set Current Database"
       },
+      {
+        "command": "codeQL.viewAst",
+        "title": "CodeQL: View AST"
+      },
       {
         "command": "codeQL.upgradeCurrentDatabase",
         "title": "CodeQL: Upgrade Current Database"
@@ -213,8 +319,20 @@
         "title": "Show Database Directory"
       },
       {
-        "command": "codeQL.downloadDatabase",
-        "title": "CodeQL: Download database"
+        "command": "codeQL.chooseDatabaseFolder",
+        "title": "CodeQL: Choose Database from Folder"
+      },
+      {
+        "command": "codeQL.chooseDatabaseArchive",
+        "title": "CodeQL: Choose Database from Archive"
+      },
+      {
+        "command": "codeQL.chooseDatabaseInternet",
+        "title": "CodeQL: Download Database"
+      },
+      {
+        "command": "codeQL.chooseDatabaseLgtm",
+        "title": "CodeQL: Download Database from LGTM"
       },
       {
         "command": "codeQLDatabases.sortByName",
@@ -238,15 +356,51 @@
       },
       {
         "command": "codeQLQueryHistory.openQuery",
-        "title": "Open Query"
-      },
-      {
-        "command": "codeQLQueryHistory.removeHistoryItem",
-        "title": "Remove History Item"
+        "title": "Open the query that produced these results",
+        "icon": {
+          "light": "media/light/edit.svg",
+          "dark": "media/dark/edit.svg"
+        }
       },
       {
         "command": "codeQLQueryHistory.itemClicked",
-        "title": "Query History Item"
+        "title": "Open Query Results",
+        "icon": {
+          "light": "media/light/preview.svg",
+          "dark": "media/dark/preview.svg"
+        }
+      },
+      {
+        "command": "codeQLQueryHistory.removeHistoryItem",
+        "title": "Remove History Item(s)",
+        "icon": {
+          "light": "media/light/trash.svg",
+          "dark": "media/dark/trash.svg"
+        }
+      },
+      {
+        "command": "codeQLQueryHistory.sortByName",
+        "title": "Sort by Name",
+        "icon": {
+          "light": "media/light/sort-alpha.svg",
+          "dark": "media/dark/sort-alpha.svg"
+        }
+      },
+      {
+        "command": "codeQLQueryHistory.sortByDate",
+        "title": "Sort by Query Date",
+        "icon": {
+          "light": "media/light/sort-date.svg",
+          "dark": "media/dark/sort-date.svg"
+        }
+      },
+      {
+        "command": "codeQLQueryHistory.sortByCount",
+        "title": "Sort by Results Count",
+        "icon": {
+          "light": "media/light/sort-num.svg",
+          "dark": "media/dark/sort-num.svg"
+        }
       },
       {
         "command": "codeQLQueryHistory.showQueryLog",
@@ -256,6 +410,26 @@
         "command": "codeQLQueryHistory.showQueryText",
         "title": "Show Query Text"
       },
+      {
+        "command": "codeQLQueryHistory.viewCsvResults",
+        "title": "View Results (CSV)"
+      },
+      {
+        "command": "codeQLQueryHistory.viewSarifResults",
+        "title": "View Results (SARIF)"
+      },
+      {
+        "command": "codeQLQueryHistory.viewDil",
+        "title": "View DIL"
+      },
+      {
+        "command": "codeQLQueryHistory.setLabel",
+        "title": "Set Label"
+      },
+      {
+        "command": "codeQLQueryHistory.compareWith",
+        "title": "Compare Results"
+      },
       {
         "command": "codeQLQueryResults.nextPathStep",
         "title": "CodeQL: Show Next Step on Path"
@@ -264,21 +438,29 @@
         "command": "codeQLQueryResults.previousPathStep",
         "title": "CodeQL: Show Previous Step on Path"
       },
-      {
-        "command": "codeQLQueryHistory.setLabel",
-        "title": "Set Label"
-      },
       {
         "command": "codeQL.restartQueryServer",
         "title": "CodeQL: Restart Query Server"
       },
       {
         "command": "codeQLTests.showOutputDifferences",
-        "title": "CodeQL: Show Test Output Differences"
+        "title": "Show Test Output Differences"
       },
       {
         "command": "codeQLTests.acceptOutput",
-        "title": "CodeQL: Accept Test Output"
+        "title": "Accept Test Output"
+      },
+      {
+        "command": "codeQLAstViewer.gotoCode",
+        "title": "Go To Code"
+      },
+      {
+        "command": "codeQLAstViewer.clear",
+        "title": "Clear AST",
+        "icon": {
+          "light": "media/light/clear-all.svg",
+          "dark": "media/dark/clear-all.svg"
+        }
       }
     ],
     "menus": {
@@ -294,9 +476,59 @@
           "group": "navigation"
         },
         {
-          "command": "codeQL.chooseDatabase",
+          "command": "codeQLDatabases.chooseDatabaseFolder",
           "when": "view == codeQLDatabases",
           "group": "navigation"
+        },
+        {
+          "command": "codeQLDatabases.chooseDatabaseArchive",
+          "when": "view == codeQLDatabases",
+          "group": "navigation"
+        },
+        {
+          "command": "codeQLDatabases.chooseDatabaseInternet",
+          "when": "view == codeQLDatabases",
+          "group": "navigation"
+        },
+        {
+          "command": "codeQLDatabases.chooseDatabaseLgtm",
+          "when": "view == codeQLDatabases",
+          "group": "navigation"
+        },
+        {
+          "command": "codeQLQueryHistory.openQuery",
+          "when": "view == codeQLQueryHistory",
+          "group": "navigation"
+        },
+        {
+          "command": "codeQLQueryHistory.itemClicked",
+          "when": "view == codeQLQueryHistory",
+          "group": "navigation"
+        },
+        {
+          "command": "codeQLQueryHistory.removeHistoryItem",
+          "when": "view == codeQLQueryHistory",
+          "group": "navigation"
+        },
+        {
+          "command": "codeQLQueryHistory.sortByName",
+          "when": "view == codeQLQueryHistory",
+          "group": "navigation"
+        },
+        {
+          "command": "codeQLQueryHistory.sortByDate",
+          "when": "view == codeQLQueryHistory",
+          "group": "navigation"
+        },
+        {
+          "command": "codeQLQueryHistory.sortByCount",
+          "when": "view == codeQLQueryHistory",
+          "group": "navigation"
+        },
+        {
+          "command": "codeQLAstViewer.clear",
+          "when": "view == codeQLAstViewer",
+          "group": "navigation"
         }
       ],
       "view/item/context": [
@@ -340,6 +572,11 @@
           "group": "9_qlCommands",
           "when": "view == codeQLQueryHistory"
         },
+        {
+          "command": "codeQLQueryHistory.compareWith",
+          "group": "9_qlCommands",
+          "when": "view == codeQLQueryHistory"
+        },
         {
           "command": "codeQLQueryHistory.showQueryLog",
           "group": "9_qlCommands",
@@ -350,6 +587,21 @@
           "group": "9_qlCommands",
           "when": "view == codeQLQueryHistory"
         },
+        {
+          "command": "codeQLQueryHistory.viewCsvResults",
+          "group": "9_qlCommands",
+          "when": "view == codeQLQueryHistory && viewItem == interpretedResultsItem"
+        },
+        {
+          "command": "codeQLQueryHistory.viewSarifResults",
+          "group": "9_qlCommands",
+          "when": "view == codeQLQueryHistory && viewItem == interpretedResultsItem"
+        },
+        {
+          "command": "codeQLQueryHistory.viewDil",
+          "group": "9_qlCommands",
+          "when": "view == codeQLQueryHistory"
+        },
         {
           "command": "codeQLTests.showOutputDifferences",
           "group": "qltest@1",
@@ -365,12 +617,22 @@
         {
           "command": "codeQL.setCurrentDatabase",
           "group": "9_qlCommands",
-          "when": "resourceScheme == codeql-zip-archive || explorerResourceIsFolder"
+          "when": "resourceScheme == codeql-zip-archive || explorerResourceIsFolder || resourceExtname == .zip"
         },
         {
-          "command": "codeQL.runQuery",
+          "command": "codeQL.viewAst",
           "group": "9_qlCommands",
-          "when": "resourceLangId == ql && resourceExtname == .ql"
+          "when": "resourceScheme == codeql-zip-archive"
+        },
+        {
+          "command": "codeQL.runQueries",
+          "group": "9_qlCommands",
+          "when": "resourceScheme != codeql-zip-archive"
+        },
+        {
+          "command": "codeQL.openReferencedFile",
+          "group": "9_qlCommands",
+          "when": "resourceExtname == .qlref"
         }
       ],
       "commandPalette": [
@@ -379,17 +641,25 @@
           "when": "resourceLangId == ql && resourceExtname == .ql"
         },
         {
-          "command": "codeQL.downloadDatabase",
-          "when": "true"
+          "command": "codeQL.runQueries",
+          "when": "false"
         },
         {
           "command": "codeQL.quickEval",
           "when": "editorLangId == ql"
         },
+        {
+          "command": "codeQL.openReferencedFile",
+          "when": "resourceExtname == .qlref"
+        },
         {
           "command": "codeQL.setCurrentDatabase",
           "when": "false"
         },
+        {
+          "command": "codeQL.viewAst",
+          "when": "resourceScheme == codeql-zip-archive"
+        },
         {
           "command": "codeQLDatabases.setCurrentDatabase",
           "when": "false"
@@ -414,6 +684,30 @@
           "command": "codeQLDatabases.removeDatabase",
           "when": "false"
         },
+        {
+          "command": "codeQLDatabases.chooseDatabaseFolder",
+          "when": "false"
+        },
+        {
+          "command": "codeQLDatabases.chooseDatabaseArchive",
+          "when": "false"
+        },
+        {
+          "command": "codeQLDatabases.removeOrphanedDatabases",
+          "when": "false"
+        },
+        {
+          "command": "codeQLDatabases.chooseDatabaseInternet",
+          "when": "false"
+        },
+        {
+          "command": "codeQLDatabases.chooseDatabaseLgtm",
+          "when": "false"
+        },
+        {
+          "command": "codeQLDatabases.upgradeDatabase",
+          "when": "false"
+        },
         {
           "command": "codeQLQueryHistory.openQuery",
           "when": "false"
@@ -434,9 +728,53 @@
           "command": "codeQLQueryHistory.showQueryText",
           "when": "false"
         },
+        {
+          "command": "codeQLQueryHistory.viewCsvResults",
+          "when": "false"
+        },
+        {
+          "command": "codeQLQueryHistory.viewSarifResults",
+          "when": "false"
+        },
+        {
+          "command": "codeQLQueryHistory.viewDil",
+          "when": "false"
+        },
         {
           "command": "codeQLQueryHistory.setLabel",
           "when": "false"
+        },
+        {
+          "command": "codeQLQueryHistory.compareWith",
+          "when": "false"
+        },
+        {
+          "command": "codeQLQueryHistory.sortByName",
+          "when": "false"
+        },
+        {
+          "command": "codeQLQueryHistory.sortByDate",
+          "when": "false"
+        },
+        {
+          "command": "codeQLQueryHistory.sortByCount",
+          "when": "false"
+        },
+        {
+          "command": "codeQLAstViewer.gotoCode",
+          "when": "false"
+        },
+        {
+          "command": "codeQLAstViewer.clear",
+          "when": "false"
+        },
+        {
+          "command": "codeQLTests.acceptOutput",
+          "when": "false"
+        },
+        {
+          "command": "codeQLTests.showOutputDifferences",
+          "when": "false"
         }
       ],
       "editor/context": [
@@ -444,9 +782,17 @@
           "command": "codeQL.runQuery",
           "when": "editorLangId == ql && resourceExtname == .ql"
         },
+        {
+          "command": "codeQL.viewAst",
+          "when": "resourceScheme == codeql-zip-archive"
+        },
         {
           "command": "codeQL.quickEval",
           "when": "editorLangId == ql"
+        },
+        {
+          "command": "codeQL.openReferencedFile",
+          "when": "resourceExtname == .qlref"
         }
       ]
     },
@@ -468,9 +814,27 @@
         {
           "id": "codeQLQueryHistory",
           "name": "Query History"
+        },
+        {
+          "id": "codeQLAstViewer",
+          "name": "AST Viewer"
         }
       ]
-    }
+    },
+    "viewsWelcome": [
+      {
+        "view": "codeQLAstViewer",
+        "contents": "Run the 'CodeQL: View AST' command on an open source file from a CodeQL database.\n[View AST](command:codeQL.viewAst)"
+      },
+      {
+        "view": "codeQLQueryHistory",
+        "contents": "Run the 'CodeQL: Run Query' command on a QL query.\n[Run Query](command:codeQL.runQuery)"
+      },
+      {
+        "view": "codeQLDatabases",
+        "contents": "Add a CodeQL database:\n[From a folder](command:codeQLDatabases.chooseDatabaseFolder)\n[From an archive](command:codeQLDatabases.chooseDatabaseArchive)\n[From a URL (as a zip file)](command:codeQLDatabases.chooseDatabaseInternet)\n[From LGTM](command:codeQLDatabases.chooseDatabaseLgtm)"
+      }
+    ]
   },
   "scripts": {
     "build": "gulp",
@@ -478,96 +842,105 @@
     "watch:extension": "tsc --watch",
     "test": "mocha --exit -r ts-node/register test/pure-tests/**/*.ts",
     "preintegration": "rm -rf ./out/vscode-tests && gulp",
-    "integration": "node ./out/vscode-tests/run-integration-tests.js",
+    "integration": "node ./out/vscode-tests/run-integration-tests.js no-workspace,minimal-workspace",
+    "cli-integration": "npm run preintegration && node ./out/vscode-tests/run-integration-tests.js cli-integration",
     "update-vscode": "node ./node_modules/vscode/bin/install",
-    "postinstall": "node ./node_modules/vscode/bin/install",
-    "format": "tsfmt -r",
-    "lint": "eslint src test --ext .ts,.tsx",
-    "lint-staged": "lint-staged"
+    "format": "tsfmt -r && eslint src test --ext .ts,.tsx --fix",
+    "lint": "eslint src test --ext .ts,.tsx --max-warnings=0",
+    "format-staged": "lint-staged"
   },
   "dependencies": {
     "child-process-promise": "^2.2.1",
     "classnames": "~2.2.6",
-    "fs-extra": "^8.1.0",
+    "fs-extra": "^9.0.1",
     "glob-promise": "^3.4.0",
-    "js-yaml": "^3.12.0",
+    "js-yaml": "^3.14.0",
+    "minimist": "~1.2.5",
     "node-fetch": "~2.6.0",
+    "path-browserify": "^1.0.1",
     "react": "^16.8.6",
     "react-dom": "^16.8.6",
-    "semmle-bqrs": "^0.0.1",
-    "semmle-io-node": "^0.0.1",
-    "semmle-vscode-utils": "^0.0.1",
+    "semver": "~7.3.2",
     "tmp": "^0.1.0",
+    "tmp-promise": "~3.0.2",
     "tree-kill": "~1.2.2",
     "unzipper": "~0.10.5",
+    "vscode-extension-telemetry": "^0.1.6",
     "vscode-jsonrpc": "^5.0.1",
     "vscode-languageclient": "^6.1.3",
     "vscode-test-adapter-api": "~1.7.0",
     "vscode-test-adapter-util": "~0.7.0",
-    "minimist": "~1.2.5"
+    "zip-a-folder": "~0.0.12"
   },
   "devDependencies": {
     "@types/chai": "^4.1.7",
+    "@types/chai-as-promised": "~7.1.2",
     "@types/child-process-promise": "^2.2.1",
     "@types/classnames": "~2.2.9",
-    "@types/fs-extra": "^8.0.0",
+    "@types/fs-extra": "^9.0.6",
     "@types/glob": "^7.1.1",
     "@types/google-protobuf": "^3.2.7",
     "@types/gulp": "^4.0.6",
-    "@types/js-yaml": "~3.12.1",
+    "@types/gulp-replace": "0.0.31",
+    "@types/gulp-sourcemaps": "0.0.32",
+    "@types/js-yaml": "^3.12.5",
     "@types/jszip": "~3.1.6",
-    "@types/mocha": "~5.2.7",
-    "@types/node": "^12.0.8",
+    "@types/mocha": "^8.2.0",
+    "@types/node": "^12.14.1",
     "@types/node-fetch": "~2.5.2",
+    "@types/proxyquire": "~1.3.28",
     "@types/react": "^16.8.17",
     "@types/react-dom": "^16.8.4",
     "@types/sarif": "~2.1.2",
+    "@types/semver": "~7.2.0",
+    "@types/sinon": "~7.5.2",
+    "@types/sinon-chai": "~3.2.3",
+    "@types/through2": "^2.0.36",
     "@types/tmp": "^0.1.0",
     "@types/unzipper": "~0.10.1",
-    "@types/vscode": "^1.39.0",
+    "@types/vscode": "^1.43.0",
     "@types/webpack": "^4.32.1",
     "@types/xml2js": "~0.4.4",
-    "build-tasks": "^0.0.1",
-    "chai": "^4.2.0",
-    "css-loader": "~3.1.0",
-    "glob": "^7.1.4",
-    "gulp": "^4.0.2",
-    "gulp-sourcemaps": "^2.6.5",
-    "gulp-typescript": "^5.0.1",
-    "mocha": "~6.2.1",
-    "mocha-sinon": "~2.1.0",
-    "npm-run-all": "^4.1.5",
-    "sinon": "~9.0.0",
-    "style-loader": "~0.23.1",
-    "through2": "^3.0.1",
-    "ts-loader": "^5.4.5",
-    "ts-node": "^8.3.0",
-    "ts-protoc-gen": "^0.9.0",
-    "typescript": "^3.7.2",
-    "typescript-config": "^0.0.1",
-    "typescript-formatter": "^7.2.2",
-    "vsce": "^1.65.0",
-    "vscode-test": "^1.0.0",
-    "webpack": "^4.38.0",
-    "webpack-cli": "^3.3.2",
-    "eslint": "~6.8.0",
     "@typescript-eslint/eslint-plugin": "~2.23.0",
     "@typescript-eslint/parser": "~2.23.0",
+    "ansi-colors": "^4.1.1",
+    "applicationinsights": "^1.8.7",
+    "chai": "^4.2.0",
     "chai-as-promised": "~7.1.1",
-    "@types/chai-as-promised": "~7.1.2",
-    "@types/sinon": "~7.5.2",
-    "sinon-chai": "~3.5.0",
-    "@types/sinon-chai": "~3.2.3",
-    "proxyquire": "~2.1.3",
-    "@types/proxyquire": "~1.3.28",
+    "css-loader": "~3.1.0",
+    "eslint": "~6.8.0",
     "eslint-plugin-react": "~7.19.0",
+    "glob": "^7.1.4",
+    "gulp": "^4.0.2",
+    "gulp-replace": "^1.0.0",
+    "gulp-sourcemaps": "^2.6.5",
+    "gulp-typescript": "^5.0.1",
     "husky": "~4.2.5",
+    "jsonc-parser": "^2.3.0",
     "lint-staged": "~10.2.2",
-    "prettier": "~2.0.5"
+    "mocha": "^8.2.1",
+    "mocha-sinon": "~2.1.0",
+    "npm-run-all": "^4.1.5",
+    "prettier": "~2.0.5",
+    "proxyquire": "~2.1.3",
+    "sinon": "~9.0.0",
+    "sinon-chai": "~3.5.0",
+    "style-loader": "~0.23.1",
+    "through2": "^3.0.1",
+    "ts-loader": "^8.1.0",
+    "ts-node": "^8.3.0",
+    "ts-protoc-gen": "^0.9.0",
+    "typescript": "~3.8.3",
+    "typescript-formatter": "^7.2.2",
+    "vsce": "^1.65.0",
+    "vscode-test": "^1.4.0",
+    "webpack": "^5.28.0",
+    "webpack-cli": "^4.6.0"
   },
   "husky": {
     "hooks": {
-      "pre-commit": "npm run lint-staged"
+      "pre-commit": "npm run format-staged",
+      "pre-push": "npm run lint"
     }
   },
   "lint-staged": {
@@ -575,8 +948,8 @@
       "prettier --write"
     ],
     "./**/*.{ts,tsx}": [
-      "eslint --fix --debug",
-      "tsfmt -r"
+      "tsfmt -r",
+      "eslint --fix"
     ]
   }
 }

extensions/ql-vscode/snippets.json

@@ -0,0 +1,134 @@
+{
+  "Query Metadata": {
+    "prefix": "querymetadata",
+    "body": [
+      "/**",
+      " * @name $1",
+      " * @description $2",
+      " * @kind $3",
+      " * @id $4",
+      " * @tags $5",
+      " */"
+    ],
+    "description": "Metadata for a query"
+  },
+  "Class": {
+    "prefix": "class",
+    "body": ["class $1 extends $2 {", "\t$0", "}"],
+    "description": "A class"
+  },
+  "From/Where/Select": {
+    "prefix": "from",
+    "body": ["from $1", "where $2", "select $3"],
+    "description": "A from/where/select statement"
+  },
+  "Predicate": {
+    "prefix": "predicate",
+    "body": ["predicate $1($2) {", "\t$0", "}"],
+    "description": "A predicate"
+  },
+  "Dataflow Tracking Class": {
+    "prefix": "dataflowtracking",
+    "body": [
+      "class $1 extends DataFlow::Configuration {",
+      "\t$1() { this = \"$1\" }",
+      "\t",
+      "\toverride predicate isSource(DataFlow::Node node) {",
+      "\t\t${2:none()}",
+      "\t}",
+      "\t",
+      "\toverride predicate isSink(DataFlow::Node node) {",
+      "\t\t${3:none()}",
+      "\t}",
+      "}"
+    ],
+    "description": "Boilerplate for a dataflow tracking class"
+  },
+  "Taint Tracking Class": {
+    "prefix": "tainttracking",
+    "body": [
+      "class $1 extends TaintTracking::Configuration {",
+      "\t$1() { this = \"$1\" }",
+      "\t",
+      "\toverride predicate isSource(DataFlow::Node node) {",
+      "\t\t${2:none()}",
+      "\t}",
+      "\t",
+      "\toverride predicate isSink(DataFlow::Node node) {",
+      "\t\t${3:none()}",
+      "\t}",
+      "}"
+    ],
+    "description": "Boilerplate for a taint tracking class"
+  },
+  "Count": {
+    "prefix": "count",
+    "body": ["count($1 | $2 | $3)"],
+    "description": "A count aggregate"
+  },
+  "Max": {
+    "prefix": "max",
+    "body": ["max($1 | $2 | $3)"],
+    "description": "A max aggregate"
+  },
+  "Min": {
+    "prefix": "min",
+    "body": ["min($1 | $2 | $3)"],
+    "description": "A min aggregate"
+  },
+  "Average": {
+    "prefix": "avg",
+    "body": ["avg($1 | $2 | $3)"],
+    "description": "An average aggregate"
+  },
+  "Sum": {
+    "prefix": "sum",
+    "body": ["sum($1 | $2 | $3)"],
+    "description": "A sum aggregate"
+  },
+  "Concatenation": {
+    "prefix": "concat",
+    "body": ["concat($1 | $2 | $3)"],
+    "description": "A concatenation aggregate"
+  },
+  "Rank": {
+    "prefix": "rank",
+    "body": ["rank[$1]($2 | $3 | $4)"],
+    "description": "A rank aggregate"
+  },
+  "Strict Sum": {
+    "prefix": "strictsum",
+    "body": ["strictsum($1 | $2 | $3)"],
+    "description": "A strict sum aggregate"
+  },
+  "Strict Concatenation": {
+    "prefix": "strictconcat",
+    "body": ["strictconcat($1 | $2 | $3)"],
+    "description": "A strict concatenation aggregate"
+  },
+  "Strict Count": {
+    "prefix": "strictcount",
+    "body": ["strictcount($1 | $2 | $3)"],
+    "description": "A strict count aggregate"
+  },
+  "Unique": {
+    "prefix": "unique",
+    "body": ["unique($1 | $2 | $3)"],
+    "description": "A unique aggregate"
+  },
+  "Exists": {
+    "prefix": "exists",
+    "body": ["exists($1 | $2 | $3)"],
+    "description": "An exists quantifier"
+  },
+  "For All": {
+    "prefix": "forall",
+    "body": ["forall($1 | $2 | $3)"],
+    "description": "A for all quantifier"
+  },
+  "For All and Exists": {
+    "prefix": "forex",
+    "body": ["forex($1 | $2 | $3)"],
+    "description": "A for all and exists quantifier"
+  }
+}

extensions/ql-vscode/src/adapt.ts

@@ -1,103 +0,0 @@
-import { DecodedBqrsChunk, ResultSetSchema, ColumnKind, Column, ColumnValue } from "./bqrs-cli-types";
-import { LocationValue, ResultSetSchema as AdaptedSchema, ColumnSchema, ColumnType, LocationStyle } from 'semmle-bqrs';
-
-// FIXME: This is a temporary bit of impedance matching to convert
-// from the types provided by ./bqrs-cli-types, to the types used by
-// the view layer.
-//
-// The reason that it is benign for now is that it is only used by
-// feature-flag-guarded codepaths that won't be encountered by normal
-// users. It is not yet guaranteed to produce correct output for raw
-// results.
-//
-// Eventually, the view layer should be refactored to directly accept data
-// of types coming from bqrs-cli-types, and this file can be deleted.
-
-export type ResultRow = ResultValue[];
-
-export interface ResultElement {
-  label: string;
-  location?: LocationValue;
-}
-
-export interface ResultUri {
-  uri: string;
-}
-
-export type ResultValue = ResultElement | ResultUri | string;
-
-export interface RawResultSet {
-  readonly schema: AdaptedSchema;
-  readonly rows: readonly ResultRow[];
-}
-
-function adaptKind(kind: ColumnKind): ColumnType {
-  // XXX what about 'u'?
-  if (kind === 'e') {
-    return { type: 'e', primitiveType: 's', locationStyle: LocationStyle.FivePart, hasLabel: true }
-  }
-  else {
-    return { type: kind };
-  }
-}
-
-function adaptColumn(col: Column): ColumnSchema {
-  return { name: col.name!, type: adaptKind(col.kind) };
-}
-
-export function adaptSchema(schema: ResultSetSchema): AdaptedSchema {
-  return {
-    columns: schema.columns.map(adaptColumn),
-    name: schema.name,
-    tupleCount: schema.rows,
-    version: 0,
-  }
-}
-
-export function adaptValue(val: ColumnValue): ResultValue {
-  // XXX taking a lot of incorrect shortcuts here
-
-  if (typeof val === 'string') {
-    return val;
-  }
-
-  if (typeof val === 'number' || typeof val === 'boolean') {
-    return val + '';
-  }
-
-  const url = val.url;
-
-  if (typeof url === 'string') {
-    return url;
-  }
-
-  if (url === undefined) {
-    return 'none';
-  }
-
-  return {
-    label: val.label || '',
-    location: {
-      t: LocationStyle.FivePart,
-      lineStart: url.startLine,
-      lineEnd: url.endLine,
-      colStart: url.startColumn,
-      colEnd: url.endColumn,
-      // FIXME: This seems definitely wrong. Should we be using
-      // something like the code in sarif-utils.ts?
-      file: url.uri.replace(/file:/, ''),
-    }
-  }
-
-}
-
-export function adaptRow(row: ColumnValue[]): ResultRow {
-  return row.map(adaptValue);
-}
-
-export function adaptBqrs(schema: AdaptedSchema, page: DecodedBqrsChunk): RawResultSet {
-  return {
-    schema,
-    rows: page.tuples.map(adaptRow),
-  }
-}

extensions/ql-vscode/src/archive-filesystem-provider.ts

@@ -84,12 +84,25 @@ export function encodeSourceArchiveUri(ref: ZipFileReference): vscode.Uri {
   // This lets us separate the paths, ignoring the leading slash if we added one.
   const sourceArchiveZipPathEndIndex = sourceArchiveZipPathStartIndex + sourceArchiveZipPath.length;
   const authority = `${sourceArchiveZipPathStartIndex}-${sourceArchiveZipPathEndIndex}`;
-  return vscode.Uri.parse(zipArchiveScheme + ':/').with({
+  return vscode.Uri.parse(zipArchiveScheme + ':/', true).with({
     path: encodedPath,
     authority,
   });
 }
 
+/**
+ * Convenience method to create a codeql-zip-archive with a path to the root
+ * archive
+ *
+ * @param pathToArchive the filesystem path to the root of the archive
+ */
+export function encodeArchiveBasePath(sourceArchiveZipPath: string) {
+  return encodeSourceArchiveUri({
+    sourceArchiveZipPath,
+    pathWithinSourceArchive: ''
+  });
+}
+
 const sourceArchiveUriAuthorityPattern = /^(\d+)-(\d+)$/;
 
 class InvalidSourceArchiveUriError extends Error {
@@ -100,6 +113,14 @@ class InvalidSourceArchiveUriError extends Error {
 
 /** Decodes an encoded source archive URI into its corresponding paths. Inverse of `encodeSourceArchiveUri`. */
 export function decodeSourceArchiveUri(uri: vscode.Uri): ZipFileReference {
+  if (!uri.authority) {
+    // Uri is malformed, but this is recoverable
+    logger.log(`Warning: ${new InvalidSourceArchiveUriError(uri).message}`);
+    return {
+      pathWithinSourceArchive: '/',
+      sourceArchiveZipPath: uri.path
+    };
+  }
   const match = sourceArchiveUriAuthorityPattern.exec(uri.authority);
   if (match === null)
     throw new InvalidSourceArchiveUriError(uri);
@@ -108,7 +129,7 @@ export function decodeSourceArchiveUri(uri: vscode.Uri): ZipFileReference {
   if (isNaN(zipPathStartIndex) || isNaN(zipPathEndIndex))
     throw new InvalidSourceArchiveUriError(uri);
   return {
-    pathWithinSourceArchive: uri.path.substring(zipPathEndIndex),
+    pathWithinSourceArchive: uri.path.substring(zipPathEndIndex) || '/',
     sourceArchiveZipPath: uri.path.substring(zipPathStartIndex, zipPathEndIndex),
   };
 }
@@ -173,7 +194,7 @@ export class ArchiveFileSystemProvider implements vscode.FileSystemProvider {
     const ref = decodeSourceArchiveUri(uri);
     const archive = await this.getArchive(ref.sourceArchiveZipPath);
     const contents = archive.dirMap.get(ref.pathWithinSourceArchive);
-    const result = contents === undefined ? [] : Array.from(contents.entries());
+    const result = contents === undefined ? undefined : Array.from(contents.entries());
     if (result === undefined) {
       throw vscode.FileSystemError.FileNotFound(uri);
     }
@@ -238,7 +259,7 @@ export class ArchiveFileSystemProvider implements vscode.FileSystemProvider {
     if (archive.dirMap.has(reqPath)) {
       return new Directory(reqPath);
     }
-    throw vscode.FileSystemError.FileNotFound(uri);
+    throw vscode.FileSystemError.FileNotFound(`uri '${uri.toString()}', interpreted as '${reqPath}' in archive '${ref.sourceArchiveZipPath}'`);
   }
 
   private async _lookupAsFile(uri: vscode.Uri): Promise<File> {

extensions/ql-vscode/src/astViewer.ts

@@ -0,0 +1,204 @@
+import {
+  window,
+  TreeDataProvider,
+  EventEmitter,
+  Event,
+  ProviderResult,
+  TreeItemCollapsibleState,
+  TreeItem,
+  TreeView,
+  TextEditorSelectionChangeEvent,
+  TextEditorSelectionChangeKind,
+  Location,
+  Range
+} from 'vscode';
+import * as path from 'path';
+
+import { DatabaseItem } from './databases';
+import { UrlValue, BqrsId } from './pure/bqrs-cli-types';
+import { showLocation } from './interface-utils';
+import { isStringLoc, isWholeFileLoc, isLineColumnLoc } from './pure/bqrs-utils';
+import { commandRunner } from './commandRunner';
+import { DisposableObject } from './pure/disposable-object';
+import { showAndLogErrorMessage } from './helpers';
+
+export interface AstItem {
+  id: BqrsId;
+  label?: string;
+  location?: UrlValue;
+  fileLocation?: Location;
+  children: ChildAstItem[];
+  order: number;
+}
+
+export interface ChildAstItem extends AstItem {
+  parent: ChildAstItem | AstItem;
+}
+
+class AstViewerDataProvider extends DisposableObject implements TreeDataProvider<AstItem> {
+
+  public roots: AstItem[] = [];
+  public db: DatabaseItem | undefined;
+
+  private _onDidChangeTreeData =
+    this.push(new EventEmitter<AstItem | undefined>());
+  readonly onDidChangeTreeData: Event<AstItem | undefined> =
+    this._onDidChangeTreeData.event;
+
+  constructor() {
+    super();
+    this.push(
+      commandRunner('codeQLAstViewer.gotoCode',
+        async (item: AstItem) => {
+          await showLocation(item.fileLocation);
+        })
+    );
+  }
+
+  refresh(): void {
+    this._onDidChangeTreeData.fire();
+  }
+  getChildren(item?: AstItem): ProviderResult<AstItem[]> {
+    const children = item ? item.children : this.roots;
+    return children.sort((c1, c2) => (c1.order - c2.order));
+  }
+
+  getParent(item: ChildAstItem): ProviderResult<AstItem> {
+    return item.parent;
+  }
+
+  getTreeItem(item: AstItem): TreeItem {
+    const line = this.extractLineInfo(item?.location);
+
+    const state = item.children.length
+      ? TreeItemCollapsibleState.Collapsed
+      : TreeItemCollapsibleState.None;
+    const treeItem = new TreeItem(item.label || '', state);
+    treeItem.description = line ? `Line ${line}` : '';
+    treeItem.id = String(item.id);
+    treeItem.tooltip = `${treeItem.description} ${treeItem.label}`;
+    treeItem.command = {
+      command: 'codeQLAstViewer.gotoCode',
+      title: 'Go To Code',
+      tooltip: `Go To ${item.location}`,
+      arguments: [item]
+    };
+    return treeItem;
+  }
+
+  private extractLineInfo(loc?: UrlValue) {
+    if (!loc) {
+      return '';
+    } else if (isStringLoc(loc)) {
+      return loc;
+    } else if (isWholeFileLoc(loc)) {
+      return loc.uri;
+    } else if (isLineColumnLoc(loc)) {
+      return loc.startLine;
+    } else {
+      return '';
+    }
+  }
+}
+
+export class AstViewer extends DisposableObject {
+  private treeView: TreeView<AstItem>;
+  private treeDataProvider: AstViewerDataProvider;
+  private currentFile: string | undefined;
+
+  constructor() {
+    super();
+
+    this.treeDataProvider = new AstViewerDataProvider();
+    this.treeView = window.createTreeView('codeQLAstViewer', {
+      treeDataProvider: this.treeDataProvider,
+      showCollapseAll: true
+    });
+
+    this.push(this.treeView);
+    this.push(this.treeDataProvider);
+    this.push(
+      commandRunner('codeQLAstViewer.clear', async () => {
+        this.clear();
+      })
+    );
+    this.push(window.onDidChangeTextEditorSelection(this.updateTreeSelection, this));
+  }
+
+  updateRoots(roots: AstItem[], db: DatabaseItem, fileName: string) {
+    this.treeDataProvider.roots = roots;
+    this.treeDataProvider.db = db;
+    this.treeDataProvider.refresh();
+    this.treeView.message = `AST for ${path.basename(fileName)}`;
+    this.currentFile = fileName;
+    // Handle error on reveal. This could happen if
+    // the tree view is disposed during the reveal.
+    this.treeView.reveal(roots[0], { focus: false })?.then(
+      () => { /**/ },
+      err => showAndLogErrorMessage(err)
+    );
+  }
+
+  private updateTreeSelection(e: TextEditorSelectionChangeEvent) {
+    function isInside(selectedRange: Range, astRange?: Range): boolean {
+      return !!astRange?.contains(selectedRange);
+    }
+
+    // Recursively iterate all children until we find the node with the smallest
+    // range that contains the selection.
+    // Some nodes do not have a location, but their children might, so must
+    // recurse though location-less AST nodes to see if children are correct.
+    function findBest(selectedRange: Range, items?: AstItem[]): AstItem | undefined {
+      if (!items || !items.length) {
+        return;
+      }
+      for (const item of items) {
+        let candidate: AstItem | undefined = undefined;
+        if (isInside(selectedRange, item.fileLocation?.range)) {
+          candidate = item;
+        }
+        // always iterate through children since the location of an AST node in code QL does not
+        // always cover the complete text of the node.
+        candidate = findBest(selectedRange, item.children) || candidate;
+        if (candidate) {
+          return candidate;
+        }
+      }
+      return;
+    }
+
+    // Avoid recursive tree-source code updates.
+    if (e.kind === TextEditorSelectionChangeKind.Command) {
+      return;
+    }
+
+    if (
+      this.treeView.visible &&
+      e.textEditor.document.uri.fsPath === this.currentFile &&
+      e.selections.length === 1
+    ) {
+      const selection = e.selections[0];
+      const range = selection.anchor.isBefore(selection.active)
+        ? new Range(selection.anchor, selection.active)
+        : new Range(selection.active, selection.anchor);
+
+      const targetItem = findBest(range, this.treeDataProvider.roots);
+      if (targetItem) {
+        // Handle error on reveal. This could happen if
+        // the tree view is disposed during the reveal.
+        this.treeView.reveal(targetItem)?.then(
+          () => { /**/ },
+          err => showAndLogErrorMessage(err)
+        );
+      }
+    }
+  }
+
+  private clear() {
+    this.treeDataProvider.roots = [];
+    this.treeDataProvider.db = undefined;
+    this.treeDataProvider.refresh();
+    this.treeView.message = undefined;
+    this.currentFile = undefined;
+  }
+}

extensions/ql-vscode/src/cli-version.ts

@@ -1,96 +1,24 @@
-import { runCodeQlCliCommand } from "./cli";
-import { Logger } from "./logging";
+import * as semver from 'semver';
+import { runCodeQlCliCommand } from './cli';
+import { Logger } from './logging';
 
 /**
  * Get the version of a CodeQL CLI.
  */
-export async function getCodeQlCliVersion(codeQlPath: string, logger: Logger): Promise<Version | undefined> {
-  const output: string = await runCodeQlCliCommand(
-    codeQlPath,
-    ["version"],
-    ["--format=terse"],
-    "Checking CodeQL version",
-    logger
-  );
-  return tryParseVersionString(output.trim());
-}
-
-/**
- * Try to parse a version string, returning undefined if we can't parse it.
- * 
- * Version strings must contain a major, minor, and patch version.  They may optionally
- * start with "v" and may optionally contain some "tail" string after the major, minor, and
- * patch versions, for example as in `v2.1.0+baf5bff`.
- */
-export function tryParseVersionString(versionString: string): Version | undefined {
-  const match = versionString.match(versionRegex);
-  if (match === null) {
+export async function getCodeQlCliVersion(codeQlPath: string, logger: Logger): Promise<semver.SemVer | undefined> {
+  try {
+    const output: string = await runCodeQlCliCommand(
+      codeQlPath,
+      ['version'],
+      ['--format=terse'],
+      'Checking CodeQL version',
+      logger
+    );
+    return semver.parse(output.trim()) || undefined;
+  } catch (e) {
+    // Failed to run the version command. This might happen if the cli version is _really_ old, or it is corrupted.
+    // Either way, we can't determine compatibility.
+    logger.log(`Failed to run 'codeql version'. Reason: ${e.message}`);
     return undefined;
   }
-  return {
-    buildMetadata: match[5],
-    majorVersion: Number.parseInt(match[1], 10),
-    minorVersion: Number.parseInt(match[2], 10),
-    patchVersion: Number.parseInt(match[3], 10),
-    prereleaseVersion: match[4],
-    rawString: versionString,
-  }
-}
-
-/**
- * Regex for parsing semantic versions
- * 
- * From the semver spec https://semver.org/#is-there-a-suggested-regular-expression-regex-to-check-a-semver-string
- */
-const versionRegex = new RegExp(String.raw`^v?(0|[1-9]\d*)\.(0|[1-9]\d*)\.(0|[1-9]\d*)` +
-  String.raw`(?:-((?:0|[1-9]\d*|\d*[a-zA-Z-][0-9a-zA-Z-]*)(?:\.(?:0|[1-9]\d*|\d*[a-zA-Z-][0-9a-zA-Z-]*))*))?` +
-  String.raw`(?:\+([0-9a-zA-Z-]+(?:\.[0-9a-zA-Z-]+)*))?$`);
-
-/**
- * A version of the CodeQL CLI.
- */
-export interface Version {
-  /**
-   * Build metadata
-   * 
-   * For example, this will be `abcdef0` for version 2.1.0-alpha.1+abcdef0.
-   * Build metadata must be ignored when comparing versions. 
-   */
-  buildMetadata: string | undefined;
-
-  /**
-   * Major version number
-   * 
-   * For example, this will be `2` for version 2.1.0-alpha.1+abcdef0.
-   */
-  majorVersion: number;
-
-  /**
-   * Minor version number
-   * 
-   * For example, this will be `1` for version 2.1.0-alpha.1+abcdef0.
-   */
-  minorVersion: number;
-
-  /**
-   * Patch version number
-   * 
-   * For example, this will be `0` for version 2.1.0-alpha.1+abcdef0.
-   */
-  patchVersion: number;
-
-  /**
-   * Prerelease version
-   * 
-   * For example, this will be `alpha.1` for version 2.1.0-alpha.1+abcdef0.
-   * The prerelease version must be considered when comparing versions.
-   */
-  prereleaseVersion: string | undefined;
-
-  /**
-   * Raw version string
-   * 
-   * For example, this will be `2.1.0-alpha.1+abcdef0` for version 2.1.0-alpha.1+abcdef0.
-   */
-  rawString: string;
 }

extensions/ql-vscode/src/cli.ts

@@ -4,21 +4,30 @@ import * as child_process from 'child_process';
 import * as fs from 'fs-extra';
 import * as path from 'path';
 import * as sarif from 'sarif';
+import { SemVer } from 'semver';
 import { Readable } from 'stream';
 import { StringDecoder } from 'string_decoder';
 import * as tk from 'tree-kill';
-import * as util from 'util';
+import { promisify } from 'util';
 import { CancellationToken, Disposable } from 'vscode';
-import { BQRSInfo, DecodedBqrsChunk } from "./bqrs-cli-types";
-import { DistributionProvider } from "./distribution";
-import { assertNever } from "./helpers-pure";
-import { QueryMetadata, SortDirection } from "./interface-types";
-import { Logger, ProgressReporter } from "./logging";
+
+import { BQRSInfo, DecodedBqrsChunk } from './pure/bqrs-cli-types';
+import { CliConfig } from './config';
+import { DistributionProvider, FindDistributionResultKind } from './distribution';
+import { assertNever } from './pure/helpers-pure';
+import { QueryMetadata, SortDirection } from './pure/interface-types';
+import { Logger, ProgressReporter } from './logging';
+import { CompilationMessage } from './pure/messages';
 
 /**
  * The version of the SARIF format that we are using.
  */
-const SARIF_FORMAT = "sarifv2.1.0";
+const SARIF_FORMAT = 'sarifv2.1.0';
+
+/**
+ * The string used to specify CSV format.
+ */
+const CSV_FORMAT = 'csv';
 
 /**
  * Flags to pass to all cli commands.
@@ -46,6 +55,7 @@ export interface DbInfo {
   sourceArchiveRoot: string;
   datasetFolder: string;
   logsFolder: string;
+  languages: string[];
 }
 
 /**
@@ -54,6 +64,7 @@ export interface DbInfo {
 export interface UpgradesInfo {
   scripts: string[];
   finalDbscheme: string;
+  matchesTarget?: boolean;
 }
 
 /**
@@ -61,6 +72,11 @@ export interface UpgradesInfo {
  */
 export type QlpacksInfo = { [name: string]: string[] };
 
+/**
+ * The expected output of `codeql resolve qlref`.
+ */
+export type QlrefInfo = { resolvedPath: string };
+
 // `codeql bqrs interpret` requires both of these to be present or
 // both absent.
 export interface SourceInfo {
@@ -87,10 +103,24 @@ export interface TestRunOptions {
 export interface TestCompleted {
   test: string;
   pass: boolean;
-  messages: string[];
+  messages: CompilationMessage[];
   compilationMs: number;
   evaluationMs: number;
   expected: string;
+  diff: string[] | undefined;
+  failureDescription?: string;
+}
+
+/**
+ * Optional arguments for the `bqrsDecode` function
+ */
+interface BqrsDecodeOptions {
+  /** How many results to get. */
+  pageSize?: number;
+  /** The 0-based index of the first result to get. */
+  offset?: number;
+  /** The entity names to retrieve from the bqrs file. Default is url, string */
+  entities?: string[];
 }
 
 /**
@@ -101,6 +131,7 @@ export interface TestCompleted {
  */
 export class CodeQLCliServer implements Disposable {
 
+
   /** The process for the cli server, or undefined if one doesn't exist yet */
   process?: child_process.ChildProcessWithoutNullStreams;
   /** Queue of future commands*/
@@ -110,18 +141,41 @@ export class CodeQLCliServer implements Disposable {
   /**  A buffer with a single null byte. */
   nullBuffer: Buffer;
 
-  constructor(private config: DistributionProvider, private logger: Logger) {
+  /** Version of current cli, lazily computed by the `getVersion()` method */
+  private _version: SemVer | undefined;
+
+  /** Path to current codeQL executable, or undefined if not running yet. */
+  codeQlPath: string | undefined;
+
+  cliConstraints = new CliVersionConstraint(this);
+
+  /**
+   * When set to true, ignore some modal popups and assume user has clicked "yes".
+   */
+  public quiet = false;
+
+  constructor(
+    private distributionProvider: DistributionProvider,
+    private cliConfig: CliConfig,
+    private logger: Logger
+  ) {
     this.commandQueue = [];
     this.commandInProcess = false;
     this.nullBuffer = Buffer.alloc(1);
-    if (this.config.onDidChangeDistribution) {
-      this.config.onDidChangeDistribution(() => {
+    if (this.distributionProvider.onDidChangeDistribution) {
+      this.distributionProvider.onDidChangeDistribution(() => {
         this.restartCliServer();
+        this._version = undefined;
+      });
+    }
+    if (this.cliConfig.onDidChangeConfiguration) {
+      this.cliConfig.onDidChangeConfiguration(() => {
+        this.restartCliServer();
+        this._version = undefined;
       });
     }
   }
 
-
   dispose(): void {
     this.killProcessIfRunning();
   }
@@ -131,7 +185,7 @@ export class CodeQLCliServer implements Disposable {
       // Tell the Java CLI server process to shut down.
       this.logger.log('Sending shutdown request');
       try {
-        this.process.stdin.write(JSON.stringify(["shutdown"]), "utf8");
+        this.process.stdin.write(JSON.stringify(['shutdown']), 'utf8');
         this.process.stdin.write(this.nullBuffer);
         this.logger.log('Sent shutdown request');
       } catch (e) {
@@ -165,7 +219,7 @@ export class CodeQLCliServer implements Disposable {
     // If the server is not running a command run this immediately
     // otherwise add to the front of the queue (as we want to run this after the next command()).
     if (this.commandInProcess) {
-      this.commandQueue.unshift(callback)
+      this.commandQueue.unshift(callback);
     } else {
       callback();
     }
@@ -176,7 +230,7 @@ export class CodeQLCliServer implements Disposable {
    * Get the path to the CodeQL CLI distribution, or throw an exception if not found.
    */
   private async getCodeQlPath(): Promise<string> {
-    const codeqlPath = await this.config.getCodeQlPathWithoutVersionCheck();
+    const codeqlPath = await this.distributionProvider.getCodeQlPathWithoutVersionCheck();
     if (!codeqlPath) {
       throw new Error('Failed to find CodeQL distribution.');
     }
@@ -187,20 +241,27 @@ export class CodeQLCliServer implements Disposable {
    * Launch the cli server
    */
   private async launchProcess(): Promise<child_process.ChildProcessWithoutNullStreams> {
-    const config = await this.getCodeQlPath();
-    return spawnServer(config, "CodeQL CLI Server", ["execute", "cli-server"], [], this.logger, _data => { /**/ })
+    const codeQlPath = await this.getCodeQlPath();
+    return await spawnServer(
+      codeQlPath,
+      'CodeQL CLI Server',
+      ['execute', 'cli-server'],
+      [],
+      this.logger,
+      _data => { /**/ }
+    );
   }
 
   private async runCodeQlCliInternal(command: string[], commandArgs: string[], description: string): Promise<string> {
     const stderrBuffers: Buffer[] = [];
     if (this.commandInProcess) {
-      throw new Error("runCodeQlCliInternal called while cli was running")
+      throw new Error('runCodeQlCliInternal called while cli was running');
     }
     this.commandInProcess = true;
     try {
       //Launch the process if it doesn't exist
       if (!this.process) {
-        this.process = await this.launchProcess()
+        this.process = await this.launchProcess();
       }
       // Grab the process so that typescript know that it is always defined.
       const process = this.process;
@@ -209,10 +270,10 @@ export class CodeQLCliServer implements Disposable {
 
       // Compute the full args array
       const args = command.concat(LOGGING_FLAGS).concat(commandArgs);
-      const argsString = args.join(" ");
+      const argsString = args.join(' ');
       this.logger.log(`${description} using CodeQL CLI: ${argsString}...`);
       try {
-        await new Promise((resolve, reject) => {
+        await new Promise<void>((resolve, reject) => {
           // Start listening to stdout
           process.stdout.addListener('data', (newData: Buffer) => {
             stdoutBuffers.push(newData);
@@ -228,16 +289,16 @@ export class CodeQLCliServer implements Disposable {
             stderrBuffers.push(newData);
           });
           // Listen for process exit.
-          process.addListener("close", (code) => reject(code));
+          process.addListener('close', (code) => reject(code));
           // Write the command followed by a null terminator.
-          process.stdin.write(JSON.stringify(args), "utf8")
-          process.stdin.write(this.nullBuffer)
+          process.stdin.write(JSON.stringify(args), 'utf8');
+          process.stdin.write(this.nullBuffer);
         });
         // Join all the data together
         const fullBuffer = Buffer.concat(stdoutBuffers);
         // Make sure we remove the terminator;
-        const data = fullBuffer.toString("utf8", 0, fullBuffer.length - 1);
-        this.logger.log(`CLI command succeeded.`);
+        const data = fullBuffer.toString('utf8', 0, fullBuffer.length - 1);
+        this.logger.log('CLI command succeeded.');
         return data;
       } catch (err) {
         // Kill the process if it isn't already dead.
@@ -246,15 +307,15 @@ export class CodeQLCliServer implements Disposable {
         const newError =
           stderrBuffers.length == 0
             ? new Error(`${description} failed: ${err}`)
-            : new Error(`${description} failed: ${Buffer.concat(stderrBuffers).toString("utf8")}`);
+            : new Error(`${description} failed: ${Buffer.concat(stderrBuffers).toString('utf8')}`);
         newError.stack += (err.stack || '');
         throw newError;
       } finally {
-        this.logger.log(Buffer.concat(stderrBuffers).toString("utf8"));
+        this.logger.log(Buffer.concat(stderrBuffers).toString('utf8'));
         // Remove the listeners we set up.
-        process.stdout.removeAllListeners('data')
-        process.stderr.removeAllListeners('data')
-        process.removeAllListeners("close");
+        process.stdout.removeAllListeners('data');
+        process.stderr.removeAllListeners('data');
+        process.removeAllListeners('close');
       }
     } finally {
       this.commandInProcess = false;
@@ -349,7 +410,7 @@ export class CodeQLCliServer implements Disposable {
       try {
         yield JSON.parse(event) as EventType;
       } catch (err) {
-        throw new Error(`Parsing output of ${description} failed: ${err.stderr || err}`)
+        throw new Error(`Parsing output of ${description} failed: ${err.stderr || err}`);
       }
     }
   }
@@ -375,11 +436,11 @@ export class CodeQLCliServer implements Disposable {
         } catch (err) {
           reject(err);
         }
-      }
+      };
       // If the server is not running a command, then run the given command immediately,
       // otherwise add to the queue
       if (this.commandInProcess) {
-        this.commandQueue.push(callback)
+        this.commandQueue.push(callback);
       } else {
         callback();
       }
@@ -391,17 +452,20 @@ export class CodeQLCliServer implements Disposable {
    * @param command The `codeql` command to be run, provided as an array of command/subcommand names.
    * @param commandArgs The arguments to pass to the `codeql` command.
    * @param description Description of the action being run, to be shown in log and error messages.
+   * @param addFormat Whether or not to add commandline arguments to specify the format as JSON.
    * @param progressReporter Used to output progress messages, e.g. to the status bar.
    * @returns The contents of the command's stdout, if the command succeeded.
    */
-  async runJsonCodeQlCliCommand<OutputType>(command: string[], commandArgs: string[], description: string, progressReporter?: ProgressReporter): Promise<OutputType> {
-    // Add format argument first, in case commandArgs contains positional parameters.
-    const args = ['--format', 'json'].concat(commandArgs);
+  async runJsonCodeQlCliCommand<OutputType>(command: string[], commandArgs: string[], description: string, addFormat = true, progressReporter?: ProgressReporter): Promise<OutputType> {
+    let args: string[] = [];
+    if (addFormat) // Add format argument first, in case commandArgs contains positional parameters.
+      args = args.concat(['--format', 'json']);
+    args = args.concat(commandArgs);
     const result = await this.runCodeQlCliCommand(command, args, description, progressReporter);
     try {
       return JSON.parse(result) as OutputType;
     } catch (err) {
-      throw new Error(`Parsing output of ${description} failed: ${err.stderr || err}`)
+      throw new Error(`Parsing output of ${description} failed: ${err.stderr || err}`);
     }
   }
 
@@ -413,10 +477,10 @@ export class CodeQLCliServer implements Disposable {
   async resolveLibraryPath(workspaces: string[], queryPath: string): Promise<QuerySetup> {
     const subcommandArgs = [
       '--query', queryPath,
-      "--additional-packs",
+      '--additional-packs',
       workspaces.join(path.delimiter)
     ];
-    return await this.runJsonCodeQlCliCommand<QuerySetup>(['resolve', 'library-path'], subcommandArgs, "Resolving library paths");
+    return await this.runJsonCodeQlCliCommand<QuerySetup>(['resolve', 'library-path'], subcommandArgs, 'Resolving library paths');
   }
 
   /**
@@ -428,7 +492,23 @@ export class CodeQLCliServer implements Disposable {
     const subcommandArgs = [
       testPath
     ];
-    return await this.runJsonCodeQlCliCommand<ResolvedTests>(['resolve', 'tests'], subcommandArgs, 'Resolving tests');
+    return await this.runJsonCodeQlCliCommand<ResolvedTests>(
+      ['resolve', 'tests', '--strict-test-discovery'],
+      subcommandArgs,
+      'Resolving tests'
+    );
+  }
+
+  public async resolveQlref(qlref: string): Promise<QlrefInfo> {
+    const subcommandArgs = [
+      qlref
+    ];
+    return await this.runJsonCodeQlCliCommand<QlrefInfo>(
+      ['resolve', 'qlref'],
+      subcommandArgs,
+      'Resolving qlref',
+      false
+    );
   }
 
   /**
@@ -441,11 +521,12 @@ export class CodeQLCliServer implements Disposable {
     testPaths: string[], workspaces: string[], options: TestRunOptions
   ): AsyncGenerator<TestCompleted, void, unknown> {
 
-    const subcommandArgs = [
+    const subcommandArgs = this.cliConfig.additionalTestArguments.concat([
       '--additional-packs', workspaces.join(path.delimiter),
-      '--threads', '8',
+      '--threads',
+      this.cliConfig.numberTestThreads.toString(),
       ...testPaths
-    ];
+    ]);
 
     for await (const event of await this.runAsyncCodeQlCliCommand<TestCompleted>(['test', 'run'],
       subcommandArgs, 'Run CodeQL Tests', options.cancellationToken, options.logger)) {
@@ -458,7 +539,7 @@ export class CodeQLCliServer implements Disposable {
    * @param queryPath The path to the query.
    */
   async resolveMetadata(queryPath: string): Promise<QueryMetadata> {
-    return await this.runJsonCodeQlCliCommand<QueryMetadata>(['resolve', 'metadata'], [queryPath], "Resolving query metadata");
+    return await this.runJsonCodeQlCliCommand<QueryMetadata>(['resolve', 'metadata'], [queryPath], 'Resolving query metadata');
   }
 
   /**
@@ -474,7 +555,7 @@ export class CodeQLCliServer implements Disposable {
     if (queryMemoryMb !== undefined) {
       args.push('--ram', queryMemoryMb.toString());
     }
-    return await this.runJsonCodeQlCliCommand<string[]>(['resolve', 'ram'], args, "Resolving RAM settings", progressReporter);
+    return await this.runJsonCodeQlCliCommand<string[]>(['resolve', 'ram'], args, 'Resolving RAM settings', true, progressReporter);
   }
   /**
    * Gets the headers (and optionally pagination info) of a bqrs.
@@ -483,75 +564,97 @@ export class CodeQLCliServer implements Disposable {
    */
   async bqrsInfo(bqrsPath: string, pageSize?: number): Promise<BQRSInfo> {
     const subcommandArgs = (
-      pageSize ? ["--paginate-rows", pageSize.toString()] : []
+      pageSize ? ['--paginate-rows', pageSize.toString()] : []
     ).concat(
       bqrsPath
     );
-    return await this.runJsonCodeQlCliCommand<BQRSInfo>(['bqrs', 'info'], subcommandArgs, "Reading bqrs header");
+    return await this.runJsonCodeQlCliCommand<BQRSInfo>(['bqrs', 'info'], subcommandArgs, 'Reading bqrs header');
   }
 
   /**
   * Gets the results from a bqrs.
   * @param bqrsPath The path to the bqrs.
   * @param resultSet The result set to get.
-  * @param pageSize How many results to get.
-  * @param offset The 0-based index of the first result to get.
+  * @param options Optional BqrsDecodeOptions arguments
   */
-  async bqrsDecode(bqrsPath: string, resultSet: string, pageSize?: number, offset?: number): Promise<DecodedBqrsChunk> {
+  async bqrsDecode(
+    bqrsPath: string,
+    resultSet: string,
+    { pageSize, offset, entities = ['url', 'string'] }: BqrsDecodeOptions = {}
+  ): Promise<DecodedBqrsChunk> {
+
     const subcommandArgs = [
-      "--entities=url,string",
-      "--result-set", resultSet,
+      `--entities=${entities.join(',')}`,
+      '--result-set', resultSet,
     ].concat(
-      pageSize ? ["--rows", pageSize.toString()] : []
+      pageSize ? ['--rows', pageSize.toString()] : []
     ).concat(
-      offset ? ["--start-at", offset.toString()] : []
+      offset ? ['--start-at', offset.toString()] : []
     ).concat([bqrsPath]);
-    return await this.runJsonCodeQlCliCommand<DecodedBqrsChunk>(['bqrs', 'decode'], subcommandArgs, "Reading bqrs data");
+    return await this.runJsonCodeQlCliCommand<DecodedBqrsChunk>(['bqrs', 'decode'], subcommandArgs, 'Reading bqrs data');
   }
 
-
-  async interpretBqrs(metadata: { kind: string; id: string }, resultsPath: string, interpretedResultsPath: string, sourceInfo?: SourceInfo): Promise<sarif.Log> {
+  async runInterpretCommand(format: string, metadata: QueryMetadata, resultsPath: string, interpretedResultsPath: string, sourceInfo?: SourceInfo) {
     const args = [
-      `-t=kind=${metadata.kind}`,
-      `-t=id=${metadata.id}`,
-      "--output", interpretedResultsPath,
-      "--format", SARIF_FORMAT,
+      '--output', interpretedResultsPath,
+      '--format', format,
+      // Forward all of the query metadata.
+      ...Object.entries(metadata).map(([key, value]) => `-t=${key}=${value}`)
+    ];
+    if (format == SARIF_FORMAT) {
       // TODO: This flag means that we don't group interpreted results
       // by primary location. We may want to revisit whether we call
       // interpretation with and without this flag, or do some
       // grouping client-side.
-      "--no-group-results",
-    ];
+      args.push('--no-group-results');
+    }
     if (sourceInfo !== undefined) {
       args.push(
-        "--source-archive", sourceInfo.sourceArchive,
-        "--source-location-prefix", sourceInfo.sourceLocationPrefix
+        '--source-archive', sourceInfo.sourceArchive,
+        '--source-location-prefix', sourceInfo.sourceLocationPrefix
       );
     }
+
+    args.push(
+      '--threads',
+      this.cliConfig.numberThreads.toString(),
+    );
+
     args.push(resultsPath);
-    await this.runCodeQlCliCommand(['bqrs', 'interpret'], args, "Interpreting query results");
+    await this.runCodeQlCliCommand(['bqrs', 'interpret'], args, 'Interpreting query results');
+  }
+
+  async interpretBqrs(metadata: QueryMetadata, resultsPath: string, interpretedResultsPath: string, sourceInfo?: SourceInfo): Promise<sarif.Log> {
+    await this.runInterpretCommand(SARIF_FORMAT, metadata, resultsPath, interpretedResultsPath, sourceInfo);
 
     let output: string;
     try {
       output = await fs.readFile(interpretedResultsPath, 'utf8');
-    } catch (err) {
-      throw new Error(`Reading output of interpretation failed: ${err.stderr || err}`)
+    } catch (e) {
+      const rawMessage = e.stderr || e.message;
+      const errorMessage = rawMessage.startsWith('Cannot create a string')
+        ? `SARIF too large. ${rawMessage}`
+        : rawMessage;
+      throw new Error(`Reading output of interpretation failed: ${errorMessage}`);
     }
     try {
       return JSON.parse(output) as sarif.Log;
     } catch (err) {
-      throw new Error(`Parsing output of interpretation failed: ${err.stderr || err}`)
+      throw new Error(`Parsing output of interpretation failed: ${err.stderr || err}`);
     }
   }
 
+  async generateResultsCsv(metadata: QueryMetadata, resultsPath: string, csvPath: string, sourceInfo?: SourceInfo): Promise<void> {
+    await this.runInterpretCommand(CSV_FORMAT, metadata, resultsPath, csvPath, sourceInfo);
+  }
 
   async sortBqrs(resultsPath: string, sortedResultsPath: string, resultSet: string, sortKeys: number[], sortDirections: SortDirection[]): Promise<void> {
     const sortDirectionStrings = sortDirections.map(direction => {
       switch (direction) {
         case SortDirection.asc:
-          return "asc";
+          return 'asc';
         case SortDirection.desc:
-          return "desc";
+          return 'desc';
         default:
           return assertNever(direction);
       }
@@ -559,14 +662,14 @@ export class CodeQLCliServer implements Disposable {
 
     await this.runCodeQlCliCommand(['bqrs', 'decode'],
       [
-        "--format=bqrs",
+        '--format=bqrs',
         `--result-set=${resultSet}`,
         `--output=${sortedResultsPath}`,
-        `--sort-key=${sortKeys.join(",")}`,
-        `--sort-direction=${sortDirectionStrings.join(",")}`,
+        `--sort-key=${sortKeys.join(',')}`,
+        `--sort-direction=${sortDirectionStrings.join(',')}`,
         resultsPath
       ],
-      "Sorting query results");
+      'Sorting query results');
   }
 
 
@@ -576,22 +679,29 @@ export class CodeQLCliServer implements Disposable {
    */
   resolveDatabase(databasePath: string): Promise<DbInfo> {
     return this.runJsonCodeQlCliCommand(['resolve', 'database'], [databasePath],
-      "Resolving database");
+      'Resolving database');
   }
 
   /**
    * Gets information necessary for upgrading a database.
    * @param dbScheme the path to the dbscheme of the database to be upgraded.
    * @param searchPath A list of directories to search for upgrade scripts.
+   * @param allowDowngradesIfPossible Whether we should try and include downgrades of we can.
+   * @param targetDbScheme The dbscheme to try to upgrade to.
    * @returns A list of database upgrade script directories
    */
-  resolveUpgrades(dbScheme: string, searchPath: string[]): Promise<UpgradesInfo> {
+  async resolveUpgrades(dbScheme: string, searchPath: string[], allowDowngradesIfPossible: boolean, targetDbScheme?: string): Promise<UpgradesInfo> {
     const args = ['--additional-packs', searchPath.join(path.delimiter), '--dbscheme', dbScheme];
-
-    return this.runJsonCodeQlCliCommand<UpgradesInfo>(
+    if (targetDbScheme) {
+      args.push('--target-dbscheme', targetDbScheme);
+      if (allowDowngradesIfPossible && await this.cliConstraints.supportsDowngrades()) {
+        args.push('--allow-downgrades');
+      }
+    }
+    return await this.runJsonCodeQlCliCommand<UpgradesInfo>(
       ['resolve', 'upgrades'],
       args,
-      "Resolving database upgrade scripts",
+      'Resolving database upgrade scripts',
     );
   }
 
@@ -604,14 +714,14 @@ export class CodeQLCliServer implements Disposable {
    */
   resolveQlpacks(additionalPacks: string[], searchPath?: string[]): Promise<QlpacksInfo> {
     const args = ['--additional-packs', additionalPacks.join(path.delimiter)];
-    if (searchPath !== undefined) {
+    if (searchPath?.length) {
       args.push('--search-path', path.join(...searchPath));
     }
 
     return this.runJsonCodeQlCliCommand<QlpacksInfo>(
       ['resolve', 'qlpacks'],
       args,
-      "Resolving qlpack information",
+      'Resolving qlpack information',
     );
   }
 
@@ -632,9 +742,42 @@ export class CodeQLCliServer implements Disposable {
     return this.runJsonCodeQlCliCommand<string[]>(
       ['resolve', 'queries'],
       args,
-      "Resolving queries",
+      'Resolving queries',
     );
   }
+
+  async generateDil(qloFile: string, outFile: string): Promise<void> {
+    const extraArgs = await this.cliConstraints.supportsDecompileDil()
+      ? ['--kind', 'dil', '-o', outFile, qloFile]
+      : ['-o', outFile, qloFile];
+    await this.runCodeQlCliCommand(
+      ['query', 'decompile'],
+      extraArgs,
+      'Generating DIL',
+    );
+  }
+
+  public async getVersion() {
+    if (!this._version) {
+      this._version = await this.refreshVersion();
+    }
+    return this._version;
+  }
+
+  private async refreshVersion() {
+    const distribution = await this.distributionProvider.getDistribution();
+    switch (distribution.kind) {
+      case FindDistributionResultKind.CompatibleDistribution:
+      // eslint-disable-next-line no-fallthrough
+      case FindDistributionResultKind.IncompatibleDistribution:
+        return distribution.version;
+
+      default:
+        // We should not get here because if no distributions are available, then
+        // the cli class is never instantiated.
+        throw new Error('No distribution found');
+    }
+  }
 }
 
 /**
@@ -666,7 +809,7 @@ export function spawnServer(
 
   // Start the server process.
   const base = codeqlPath;
-  const argsString = args.join(" ");
+  const argsString = args.join(' ');
   if (progressReporter !== undefined) {
     progressReporter.report({ message: `Starting ${name}` });
   }
@@ -692,7 +835,7 @@ export function spawnServer(
 
 /**
  * Runs a CodeQL CLI command without invoking the CLI server, returning the output as a string.
- * @param config The configuration containing the path to the CLI.
+ * @param codeQlPath The path to the CLI.
  * @param command The `codeql` command to be run, provided as an array of command/subcommand names.
  * @param commandArgs The arguments to pass to the `codeql` command.
  * @param description Description of the action being run, to be shown in log and error messages.
@@ -700,21 +843,28 @@ export function spawnServer(
  * @param progressReporter Used to output progress messages, e.g. to the status bar.
  * @returns The contents of the command's stdout, if the command succeeded.
  */
-export async function runCodeQlCliCommand(codeQlPath: string, command: string[], commandArgs: string[], description: string, logger: Logger, progressReporter?: ProgressReporter): Promise<string> {
+export async function runCodeQlCliCommand(
+  codeQlPath: string,
+  command: string[],
+  commandArgs: string[],
+  description: string,
+  logger: Logger,
+  progressReporter?: ProgressReporter
+): Promise<string> {
   // Add logging arguments first, in case commandArgs contains positional parameters.
   const args = command.concat(LOGGING_FLAGS).concat(commandArgs);
-  const argsString = args.join(" ");
+  const argsString = args.join(' ');
   try {
     if (progressReporter !== undefined) {
       progressReporter.report({ message: description });
     }
     logger.log(`${description} using CodeQL CLI: ${codeQlPath} ${argsString}...`);
-    const result = await util.promisify(child_process.execFile)(codeQlPath, args);
+    const result = await promisify(child_process.execFile)(codeQlPath, args);
     logger.log(result.stderr);
-    logger.log(`CLI command succeeded.`);
+    logger.log('CLI command succeeded.');
     return result.stdout;
   } catch (err) {
-    throw new Error(`${description} failed: ${err.stderr || err}`)
+    throw new Error(`${description} failed: ${err.stderr || err}`);
   }
 }
 
@@ -747,6 +897,20 @@ class SplitBuffer {
     this.buffer += this.separators[0];  // Append a separator to the end to ensure the last line is returned.
   }
 
+  /**
+   * A version of startsWith that isn't overriden by a broken version of ms-python.
+   *
+   * The definition comes from
+   * https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/startsWith
+   * which is CC0/public domain
+   *
+   * See https://github.com/github/vscode-codeql/issues/802 for more context as to why we need it.
+   */
+  private static startsWith(s: string, searchString: string, position: number): boolean {
+    const pos = position > 0 ? position | 0 : 0;
+    return s.substring(pos, pos + searchString.length) === searchString;
+  }
+
   /**
    * Extract the next full line from the buffer, if one is available.
    * @returns The text of the next available full line (without the separator), or `undefined` if no
@@ -755,7 +919,7 @@ class SplitBuffer {
   public getNextLine(): string | undefined {
     while (this.searchIndex <= (this.buffer.length - this.maxSeparatorLength)) {
       for (const separator of this.separators) {
-        if (this.buffer.startsWith(separator, this.searchIndex)) {
+        if (SplitBuffer.startsWith(this.buffer, separator, this.searchIndex)) {
           const line = this.buffer.substr(0, this.searchIndex);
           this.buffer = this.buffer.substr(this.searchIndex + separator.length);
           this.searchIndex = 0;
@@ -815,3 +979,73 @@ async function logStream(stream: Readable, logger: Logger): Promise<void> {
     logger.log(line);
   }
 }
+
+
+export function shouldDebugIdeServer() {
+  return 'IDE_SERVER_JAVA_DEBUG' in process.env
+    && process.env.IDE_SERVER_JAVA_DEBUG !== '0'
+    && process.env.IDE_SERVER_JAVA_DEBUG?.toLocaleLowerCase() !== 'false';
+}
+
+export function shouldDebugQueryServer() {
+  return 'QUERY_SERVER_JAVA_DEBUG' in process.env
+    && process.env.QUERY_SERVER_JAVA_DEBUG !== '0'
+    && process.env.QUERY_SERVER_JAVA_DEBUG?.toLocaleLowerCase() !== 'false';
+}
+
+export class CliVersionConstraint {
+
+  /**
+   * CLI version where --kind=DIL was introduced
+   */
+  public static CLI_VERSION_WITH_DECOMPILE_KIND_DIL = new SemVer('2.3.0');
+
+  /**
+   * CLI version where languages are exposed during a `codeql resolve database` command.
+   */
+  public static CLI_VERSION_WITH_LANGUAGE = new SemVer('2.4.1');
+
+  /**
+   * CLI version where `codeql resolve upgrades` supports
+   * the `--allow-downgrades` flag
+   */
+  public static CLI_VERSION_WITH_DOWNGRADES = new SemVer('2.4.4');
+
+  /**
+   * CLI version where the `codeql resolve qlref` command is available.
+   */
+  public static CLI_VERSION_WITH_RESOLVE_QLREF = new SemVer('2.5.1');
+
+  /**
+   * CLI version where database registration was introduced
+   */
+  public static CLI_VERSION_WITH_DB_REGISTRATION = new SemVer('2.4.1');
+
+  constructor(private readonly cli: CodeQLCliServer) {
+    /**/
+  }
+
+  private async isVersionAtLeast(v: SemVer) {
+    return (await this.cli.getVersion()).compare(v) >= 0;
+  }
+
+  public async supportsDecompileDil() {
+    return this.isVersionAtLeast(CliVersionConstraint.CLI_VERSION_WITH_DECOMPILE_KIND_DIL);
+  }
+
+  public async supportsLanguageName() {
+    return this.isVersionAtLeast(CliVersionConstraint.CLI_VERSION_WITH_LANGUAGE);
+  }
+
+  public async supportsDowngrades() {
+    return this.isVersionAtLeast(CliVersionConstraint.CLI_VERSION_WITH_DOWNGRADES);
+  }
+
+  public async supportsResolveQlref() {
+    return this.isVersionAtLeast(CliVersionConstraint.CLI_VERSION_WITH_RESOLVE_QLREF);
+  }
+
+  async supportsDatabaseRegistration() {
+    return this.isVersionAtLeast(CliVersionConstraint.CLI_VERSION_WITH_DB_REGISTRATION);
+  }
+}

extensions/ql-vscode/src/commandRunner.ts

@@ -0,0 +1,241 @@
+import {
+  CancellationToken,
+  ProgressOptions,
+  window as Window,
+  commands,
+  Disposable,
+  ProgressLocation
+} from 'vscode';
+import { showAndLogErrorMessage, showAndLogWarningMessage } from './helpers';
+import { logger } from './logging';
+import { telemetryListener } from './telemetry';
+
+export class UserCancellationException extends Error {
+  /**
+   * @param message The error message
+   * @param silent If silent is true, then this exception will avoid showing a warning message to the user.
+   */
+  constructor(message?: string, public readonly silent = false) {
+    super(message);
+  }
+}
+
+export interface ProgressUpdate {
+  /**
+   * The current step
+   */
+  step: number;
+  /**
+   * The maximum step. This *should* be constant for a single job.
+   */
+  maxStep: number;
+  /**
+   * The current progress message
+   */
+  message: string;
+}
+
+export type ProgressCallback = (p: ProgressUpdate) => void;
+
+/**
+ * A task that handles command invocations from `commandRunner`
+ * and includes a progress monitor.
+ *
+ *
+ * Arguments passed to the command handler are passed along,
+ * untouched to this `ProgressTask` instance.
+ *
+ * @param progress a progress handler function. Call this
+ * function with a `ProgressUpdate` instance in order to
+ * denote some progress being achieved on this task.
+ * @param token a cencellation token
+ * @param args arguments passed to this task passed on from
+ * `commands.registerCommand`.
+ */
+export type ProgressTask<R> = (
+  progress: ProgressCallback,
+  token: CancellationToken,
+  ...args: any[]
+) => Thenable<R>;
+
+/**
+ * A task that handles command invocations from `commandRunner`.
+ * Arguments passed to the command handler are passed along,
+ * untouched to this `NoProgressTask` instance.
+ *
+ * @param args arguments passed to this task passed on from
+ * `commands.registerCommand`.
+ */
+type NoProgressTask = ((...args: any[]) => Promise<any>);
+
+/**
+ * This mediates between the kind of progress callbacks we want to
+ * write (where we *set* current progress position and give
+ * `maxSteps`) and the kind vscode progress api expects us to write
+ * (which increment progress by a certain amount out of 100%).
+ *
+ * Where possible, the `commandRunner` function below should be used
+ * instead of this function. The commandRunner is meant for wrapping
+ * top-level commands and provides error handling and other support
+ * automatically.
+ *
+ * Only use this function if you need a progress monitor and the
+ * control flow does not always come from a command (eg- during
+ * extension activation, or from an internal language server
+ * request).
+ */
+export function withProgress<R>(
+  options: ProgressOptions,
+  task: ProgressTask<R>,
+  ...args: any[]
+): Thenable<R> {
+  let progressAchieved = 0;
+  return Window.withProgress(options,
+    (progress, token) => {
+      return task(p => {
+        const { message, step, maxStep } = p;
+        const increment = 100 * (step - progressAchieved) / maxStep;
+        progressAchieved = step;
+        progress.report({ message, increment });
+      }, token, ...args);
+    });
+}
+
+/**
+ * A generic wrapper for command registration. This wrapper adds uniform error handling for commands.
+ *
+ * In this variant of the command runner, no progress monitor is used.
+ *
+ * @param commandId The ID of the command to register.
+ * @param task The task to run. It is passed directly to `commands.registerCommand`. Any
+ * arguments to the command handler are passed on to the task.
+ */
+export function commandRunner(
+  commandId: string,
+  task: NoProgressTask,
+): Disposable {
+  return commands.registerCommand(commandId, async (...args: any[]) => {
+    const startTime = Date.now();
+    let error: Error | undefined;
+
+    try {
+      return await task(...args);
+    } catch (e) {
+      error = e;
+      const errorMessage = `${e.message || e} (${commandId})`;
+      if (e instanceof UserCancellationException) {
+        // User has cancelled this action manually
+        if (e.silent) {
+          logger.log(errorMessage);
+        } else {
+          showAndLogWarningMessage(errorMessage);
+        }
+      } else {
+        // Include the full stack in the error log only.
+        const fullMessage = e.stack
+          ? `${errorMessage}\n${e.stack}`
+          : errorMessage;
+        showAndLogErrorMessage(errorMessage, {
+          fullMessage
+        });
+      }
+      return undefined;
+    } finally {
+      const executionTime = Date.now() - startTime;
+      telemetryListener.sendCommandUsage(commandId, executionTime, error);
+    }
+  });
+}
+
+/**
+ * A generic wrapper for command registration.  This wrapper adds uniform error handling,
+ * progress monitoring, and cancellation for commands.
+ *
+ * @param commandId The ID of the command to register.
+ * @param task The task to run. It is passed directly to `commands.registerCommand`. Any
+ * arguments to the command handler are passed on to the task after the progress callback
+ * and cancellation token.
+ * @param progressOptions Progress options to be sent to the progress monitor.
+ */
+export function commandRunnerWithProgress<R>(
+  commandId: string,
+  task: ProgressTask<R>,
+  progressOptions: Partial<ProgressOptions>
+): Disposable {
+  return commands.registerCommand(commandId, async (...args: any[]) => {
+    const startTime = Date.now();
+    let error: Error | undefined;
+    const progressOptionsWithDefaults = {
+      location: ProgressLocation.Notification,
+      ...progressOptions
+    };
+    try {
+      return await withProgress(progressOptionsWithDefaults, task, ...args);
+    } catch (e) {
+      error = e;
+      const errorMessage = `${e.message || e} (${commandId})`;
+      if (e instanceof UserCancellationException) {
+        // User has cancelled this action manually
+        if (e.silent) {
+          logger.log(errorMessage);
+        } else {
+          showAndLogWarningMessage(errorMessage);
+        }
+      } else {
+        // Include the full stack in the error log only.
+        const fullMessage = e.stack
+          ? `${errorMessage}\n${e.stack}`
+          : errorMessage;
+        showAndLogErrorMessage(errorMessage, {
+          fullMessage
+        });
+      }
+      return undefined;
+    } finally {
+      const executionTime = Date.now() - startTime;
+      telemetryListener.sendCommandUsage(commandId, executionTime, error);
+    }
+  });
+}
+
+/**
+ * Displays a progress monitor that indicates how much progess has been made
+ * reading from a stream.
+ *
+ * @param readable The stream to read progress from
+ * @param messagePrefix A prefix for displaying the message
+ * @param totalNumBytes Total number of bytes in this stream
+ * @param progress The progress callback used to set messages
+ */
+export function reportStreamProgress(
+  readable: NodeJS.ReadableStream,
+  messagePrefix: string,
+  totalNumBytes?: number,
+  progress?: ProgressCallback
+) {
+  if (progress && totalNumBytes) {
+    let numBytesDownloaded = 0;
+    const bytesToDisplayMB = (numBytes: number): string => `${(numBytes / (1024 * 1024)).toFixed(1)} MB`;
+    const updateProgress = () => {
+      progress({
+        step: numBytesDownloaded,
+        maxStep: totalNumBytes,
+        message: `${messagePrefix} [${bytesToDisplayMB(numBytesDownloaded)} of ${bytesToDisplayMB(totalNumBytes)}]`,
+      });
+    };
+
+    // Display the progress straight away rather than waiting for the first chunk.
+    updateProgress();
+
+    readable.on('data', data => {
+      numBytesDownloaded += data.length;
+      updateProgress();
+    });
+  } else if (progress) {
+    progress({
+      step: 1,
+      maxStep: 2,
+      message: `${messagePrefix} (Size unknown)`,
+    });
+  }
+}

extensions/ql-vscode/src/compare/compare-interface.ts

@@ -0,0 +1,277 @@
+import { DisposableObject } from '../pure/disposable-object';
+import {
+  WebviewPanel,
+  ExtensionContext,
+  window as Window,
+  ViewColumn,
+  Uri,
+} from 'vscode';
+import * as path from 'path';
+
+import { tmpDir } from '../run-queries';
+import { CompletedQuery } from '../query-results';
+import {
+  FromCompareViewMessage,
+  ToCompareViewMessage,
+  QueryCompareResult,
+} from '../pure/interface-types';
+import { Logger } from '../logging';
+import { CodeQLCliServer } from '../cli';
+import { DatabaseManager } from '../databases';
+import { getHtmlForWebview, jumpToLocation } from '../interface-utils';
+import { transformBqrsResultSet, RawResultSet, BQRSInfo } from '../pure/bqrs-cli-types';
+import resultsDiff from './resultsDiff';
+
+interface ComparePair {
+  from: CompletedQuery;
+  to: CompletedQuery;
+}
+
+export class CompareInterfaceManager extends DisposableObject {
+  private comparePair: ComparePair | undefined;
+  private panel: WebviewPanel | undefined;
+  private panelLoaded = false;
+  private panelLoadedCallBacks: (() => void)[] = [];
+
+  constructor(
+    private ctx: ExtensionContext,
+    private databaseManager: DatabaseManager,
+    private cliServer: CodeQLCliServer,
+    private logger: Logger,
+    private showQueryResultsCallback: (
+      item: CompletedQuery
+    ) => Promise<void>
+  ) {
+    super();
+  }
+
+  async showResults(
+    from: CompletedQuery,
+    to: CompletedQuery,
+    selectedResultSetName?: string
+  ) {
+    this.comparePair = { from, to };
+    this.getPanel().reveal(undefined, true);
+
+    await this.waitForPanelLoaded();
+    const [
+      commonResultSetNames,
+      currentResultSetName,
+      fromResultSet,
+      toResultSet,
+    ] = await this.findCommonResultSetNames(
+      from,
+      to,
+      selectedResultSetName
+    );
+    if (currentResultSetName) {
+      let rows: QueryCompareResult | undefined;
+      let message: string | undefined;
+      try {
+        rows = this.compareResults(fromResultSet, toResultSet);
+      } catch (e) {
+        message = e.message;
+      }
+
+      await this.postMessage({
+        t: 'setComparisons',
+        stats: {
+          fromQuery: {
+            // since we split the description into several rows
+            // only run interpolation if the label is user-defined
+            // otherwise we will wind up with duplicated rows
+            name: from.options.label
+              ? from.interpolate(from.getLabel())
+              : from.queryName,
+            status: from.statusString,
+            time: from.time,
+          },
+          toQuery: {
+            name: to.options.label
+              ? to.interpolate(to.getLabel())
+              : to.queryName,
+            status: to.statusString,
+            time: to.time,
+          },
+        },
+        columns: fromResultSet.schema.columns,
+        commonResultSetNames,
+        currentResultSetName: currentResultSetName,
+        rows,
+        message,
+        datebaseUri: to.database.databaseUri,
+      });
+    }
+  }
+
+  getPanel(): WebviewPanel {
+    if (this.panel == undefined) {
+      const { ctx } = this;
+      const panel = (this.panel = Window.createWebviewPanel(
+        'compareView',
+        'Compare CodeQL Query Results',
+        { viewColumn: ViewColumn.Active, preserveFocus: true },
+        {
+          enableScripts: true,
+          enableFindWidget: true,
+          retainContextWhenHidden: true,
+          localResourceRoots: [
+            Uri.file(tmpDir.name),
+            Uri.file(path.join(this.ctx.extensionPath, 'out')),
+          ],
+        }
+      ));
+      this.panel.onDidDispose(
+        () => {
+          this.panel = undefined;
+          this.comparePair = undefined;
+        },
+        null,
+        ctx.subscriptions
+      );
+
+      const scriptPathOnDisk = Uri.file(
+        ctx.asAbsolutePath('out/compareView.js')
+      );
+
+      const stylesheetPathOnDisk = Uri.file(
+        ctx.asAbsolutePath('out/resultsView.css')
+      );
+
+      panel.webview.html = getHtmlForWebview(
+        panel.webview,
+        scriptPathOnDisk,
+        stylesheetPathOnDisk
+      );
+      panel.webview.onDidReceiveMessage(
+        async (e) => this.handleMsgFromView(e),
+        undefined,
+        ctx.subscriptions
+      );
+    }
+    return this.panel;
+  }
+
+  private waitForPanelLoaded(): Promise<void> {
+    return new Promise((resolve) => {
+      if (this.panelLoaded) {
+        resolve();
+      } else {
+        this.panelLoadedCallBacks.push(resolve);
+      }
+    });
+  }
+
+  private async handleMsgFromView(
+    msg: FromCompareViewMessage
+  ): Promise<void> {
+    switch (msg.t) {
+      case 'compareViewLoaded':
+        this.panelLoaded = true;
+        this.panelLoadedCallBacks.forEach((cb) => cb());
+        this.panelLoadedCallBacks = [];
+        break;
+
+      case 'changeCompare':
+        this.changeTable(msg.newResultSetName);
+        break;
+
+      case 'viewSourceFile':
+        await jumpToLocation(msg, this.databaseManager, this.logger);
+        break;
+
+      case 'openQuery':
+        await this.openQuery(msg.kind);
+        break;
+    }
+  }
+
+  private postMessage(msg: ToCompareViewMessage): Thenable<boolean> {
+    return this.getPanel().webview.postMessage(msg);
+  }
+
+  private async findCommonResultSetNames(
+    from: CompletedQuery,
+    to: CompletedQuery,
+    selectedResultSetName: string | undefined
+  ): Promise<[string[], string, RawResultSet, RawResultSet]> {
+    const fromSchemas = await this.cliServer.bqrsInfo(
+      from.query.resultsPaths.resultsPath
+    );
+    const toSchemas = await this.cliServer.bqrsInfo(
+      to.query.resultsPaths.resultsPath
+    );
+    const fromSchemaNames = fromSchemas['result-sets'].map(
+      (schema) => schema.name
+    );
+    const toSchemaNames = toSchemas['result-sets'].map(
+      (schema) => schema.name
+    );
+    const commonResultSetNames = fromSchemaNames.filter((name) =>
+      toSchemaNames.includes(name)
+    );
+    const currentResultSetName =
+      selectedResultSetName || commonResultSetNames[0];
+    const fromResultSet = await this.getResultSet(
+      fromSchemas,
+      currentResultSetName,
+      from.query.resultsPaths.resultsPath
+    );
+    const toResultSet = await this.getResultSet(
+      toSchemas,
+      currentResultSetName,
+      to.query.resultsPaths.resultsPath
+    );
+    return [
+      commonResultSetNames,
+      currentResultSetName,
+      fromResultSet,
+      toResultSet,
+    ];
+  }
+
+  private async changeTable(newResultSetName: string) {
+    if (!this.comparePair?.from || !this.comparePair.to) {
+      return;
+    }
+    await this.showResults(
+      this.comparePair.from,
+      this.comparePair.to,
+      newResultSetName
+    );
+  }
+
+  private async getResultSet(
+    bqrsInfo: BQRSInfo,
+    resultSetName: string,
+    resultsPath: string
+  ): Promise<RawResultSet> {
+    const schema = bqrsInfo['result-sets'].find(
+      (schema) => schema.name === resultSetName
+    );
+    if (!schema) {
+      throw new Error(`Schema ${resultSetName} not found.`);
+    }
+    const chunk = await this.cliServer.bqrsDecode(
+      resultsPath,
+      resultSetName
+    );
+    return transformBqrsResultSet(schema, chunk);
+  }
+
+  private compareResults(
+    fromResults: RawResultSet,
+    toResults: RawResultSet
+  ): QueryCompareResult {
+    // Only compare columns that have the same name
+    return resultsDiff(fromResults, toResults);
+  }
+
+  private openQuery(kind: 'from' | 'to') {
+    const toOpen =
+      kind === 'from' ? this.comparePair?.from : this.comparePair?.to;
+    if (toOpen) {
+      this.showQueryResultsCallback(toOpen);
+    }
+  }
+}

extensions/ql-vscode/src/compare/resultsDiff.ts

@@ -0,0 +1,58 @@
+import { RawResultSet } from '../pure/bqrs-cli-types';
+import { QueryCompareResult } from '../pure/interface-types';
+
+/**
+ * Compare the rows of two queries. Use deep equality to determine if
+ * rows have been added or removed across two invocations of a query.
+ *
+ * Assumptions:
+ *
+ * 1. Queries have the same sort order
+ * 2. Queries have same number and order of columns
+ * 3. Rows are not changed or re-ordered, they are only added or removed
+ *
+ * @param fromResults the source query
+ * @param toResults the target query
+ *
+ * @throws Error when:
+ *  1. number of columns do not match
+ *  2. If either query is empty
+ *  3. If the queries are 100% disjoint
+ */
+export default function resultsDiff(
+  fromResults: RawResultSet,
+  toResults: RawResultSet
+): QueryCompareResult {
+
+  if (fromResults.schema.columns.length !== toResults.schema.columns.length) {
+    throw new Error('CodeQL Compare: Columns do not match.');
+  }
+
+  if (!fromResults.rows.length) {
+    throw new Error('CodeQL Compare: Source query has no results.');
+  }
+
+  if (!toResults.rows.length) {
+    throw new Error('CodeQL Compare: Target query has no results.');
+  }
+
+  const results = {
+    from: arrayDiff(fromResults.rows, toResults.rows),
+    to: arrayDiff(toResults.rows, fromResults.rows),
+  };
+
+  if (
+    fromResults.rows.length === results.from.length &&
+    toResults.rows.length === results.to.length
+  ) {
+    throw new Error('CodeQL Compare: No overlap between the selected queries.');
+  }
+
+  return results;
+}
+
+function arrayDiff<T>(source: readonly T[], toRemove: readonly T[]): T[] {
+  // Stringify the object so that we can compare hashes in the set
+  const rest = new Set(toRemove.map((item) => JSON.stringify(item)));
+  return source.filter((element) => !rest.has(JSON.stringify(element)));
+}

extensions/ql-vscode/src/compare/view/.eslintrc.js

@@ -0,0 +1,13 @@
+module.exports = {
+  env: {
+    browser: true
+  },
+  extends: [
+    "plugin:react/recommended"
+  ],
+  settings: {
+    react: {
+      version: 'detect'
+    }
+  }
+}

extensions/ql-vscode/src/compare/view/Compare.tsx

@@ -0,0 +1,82 @@
+import * as React from 'react';
+import { useState, useEffect } from 'react';
+import * as Rdom from 'react-dom';
+
+import {
+  ToCompareViewMessage,
+  SetComparisonsMessage,
+} from '../../pure/interface-types';
+import CompareSelector from './CompareSelector';
+import { vscode } from '../../view/vscode-api';
+import CompareTable from './CompareTable';
+
+const emptyComparison: SetComparisonsMessage = {
+  t: 'setComparisons',
+  stats: {},
+  rows: undefined,
+  columns: [],
+  commonResultSetNames: [],
+  currentResultSetName: '',
+  datebaseUri: '',
+  message: 'Empty comparison'
+};
+
+export function Compare(_: {}): JSX.Element {
+  const [comparison, setComparison] = useState<SetComparisonsMessage>(
+    emptyComparison
+  );
+
+  const message = comparison.message || 'Empty comparison';
+  const hasRows = comparison.rows && (comparison.rows.to.length || comparison.rows.from.length);
+
+  useEffect(() => {
+    window.addEventListener('message', (evt: MessageEvent) => {
+      if (evt.origin === window.origin) {
+        const msg: ToCompareViewMessage = evt.data;
+        switch (msg.t) {
+          case 'setComparisons':
+            setComparison(msg);
+        }
+      } else {
+        console.error(`Invalid event origin ${evt.origin}`);
+      }
+    });
+  });
+  if (!comparison) {
+    return <div>Waiting for results to load.</div>;
+  }
+
+  try {
+    return (
+      <>
+        <div className="vscode-codeql__compare-header">
+          <div className="vscode-codeql__compare-header-item">
+            Table to compare:
+          </div>
+          <CompareSelector
+            availableResultSets={comparison.commonResultSetNames}
+            currentResultSetName={comparison.currentResultSetName}
+            updateResultSet={(newResultSetName: string) =>
+              vscode.postMessage({ t: 'changeCompare', newResultSetName })
+            }
+          />
+        </div>
+        {hasRows ? (
+          <CompareTable comparison={comparison}></CompareTable>
+        ) : (
+            <div className="vscode-codeql__compare-message">{message}</div>
+          )}
+      </>
+    );
+  } catch (err) {
+    console.error(err);
+    return <div>Error!</div>;
+  }
+}
+
+Rdom.render(
+  <Compare />,
+  document.getElementById('root'),
+  // Post a message to the extension when fully loaded.
+  () => vscode.postMessage({ t: 'compareViewLoaded' })
+);

extensions/ql-vscode/src/compare/view/CompareSelector.tsx

@@ -0,0 +1,22 @@
+import * as React from 'react';
+
+interface Props {
+  availableResultSets: string[];
+  currentResultSetName: string;
+  updateResultSet: (newResultSet: string) => void;
+}
+
+export default function CompareSelector(props: Props) {
+  return (
+    <select
+      value={props.currentResultSetName}
+      onChange={(e) => props.updateResultSet(e.target.value)}
+    >
+      {props.availableResultSets.map((resultSet) => (
+        <option key={resultSet} value={resultSet}>
+          {resultSet}
+        </option>
+      ))}
+    </select>
+  );
+}

extensions/ql-vscode/src/compare/view/CompareTable.tsx

@@ -0,0 +1,96 @@
+import * as React from 'react';
+
+import { SetComparisonsMessage } from '../../pure/interface-types';
+import RawTableHeader from '../../view/RawTableHeader';
+import { className } from '../../view/result-table-utils';
+import { ResultRow } from '../../pure/bqrs-cli-types';
+import RawTableRow from '../../view/RawTableRow';
+import { vscode } from '../../view/vscode-api';
+
+interface Props {
+  comparison: SetComparisonsMessage;
+}
+
+export default function CompareTable(props: Props) {
+  const comparison = props.comparison;
+  const rows = props.comparison.rows!;
+
+  async function openQuery(kind: 'from' | 'to') {
+    vscode.postMessage({
+      t: 'openQuery',
+      kind,
+    });
+  }
+
+  function createRows(rows: ResultRow[], databaseUri: string) {
+    return (
+      <tbody>
+        {rows.map((row, rowIndex) => (
+          <RawTableRow
+            key={rowIndex}
+            rowIndex={rowIndex}
+            row={row}
+            databaseUri={databaseUri}
+          />
+        ))}
+      </tbody>
+    );
+  }
+
+  return (
+    <table className='vscode-codeql__compare-body'>
+      <thead>
+        <tr>
+          <td>
+            <a
+              onClick={() => openQuery('from')}
+              className='vscode-codeql__compare-open'
+            >
+              {comparison.stats.fromQuery?.name}
+            </a>
+          </td>
+          <td>
+            <a
+              onClick={() => openQuery('to')}
+              className='vscode-codeql__compare-open'
+            >
+              {comparison.stats.toQuery?.name}
+            </a>
+          </td>
+        </tr>
+        <tr>
+          <td>{comparison.stats.fromQuery?.time}</td>
+          <td>{comparison.stats.toQuery?.time}</td>
+        </tr>
+        <tr>
+          <th>{rows.from.length} rows removed</th>
+          <th>{rows.to.length} rows added</th>
+        </tr>
+      </thead>
+      <tbody>
+        <tr>
+          <td>
+            <table className={className}>
+              <RawTableHeader
+                columns={comparison.columns}
+                schemaName={comparison.currentResultSetName}
+                preventSort={true}
+              />
+              {createRows(rows.from, comparison.datebaseUri)}
+            </table>
+          </td>
+          <td>
+            <table className={className}>
+              <RawTableHeader
+                columns={comparison.columns}
+                schemaName={comparison.currentResultSetName}
+                preventSort={true}
+              />
+              {createRows(rows.to, comparison.datebaseUri)}
+            </table>
+          </td>
+        </tr>
+      </tbody>
+    </table>
+  );
+}

extensions/ql-vscode/src/compare/view/tsconfig.json

@@ -0,0 +1,23 @@
+{
+  "compilerOptions": {
+    "module": "esnext",
+    "moduleResolution": "node",
+    "target": "es6",
+    "outDir": "out",
+    "lib": [
+      "es6",
+      "dom"
+    ],
+    "jsx": "react",
+    "sourceMap": true,
+    "rootDir": "..",
+    "strict": true,
+    "noUnusedLocals": true,
+    "noImplicitReturns": true,
+    "noFallthroughCasesInSwitch": true,
+    "experimentalDecorators": true
+  },
+  "exclude": [
+    "node_modules"
+  ]
+}

extensions/ql-vscode/src/config.ts

@@ -1,10 +1,10 @@
-import { DisposableObject } from 'semmle-vscode-utils';
+import { DisposableObject } from './pure/disposable-object';
 import { workspace, Event, EventEmitter, ConfigurationChangeEvent, ConfigurationTarget } from 'vscode';
 import { DistributionManager } from './distribution';
 import { logger } from './logging';
 
 /** Helper class to look up a labelled (and possibly nested) setting. */
-class Setting {
+export class Setting {
   name: string;
   parent?: Setting;
 
@@ -39,24 +39,19 @@ class Setting {
 
 const ROOT_SETTING = new Setting('codeQL');
 
-// Enable experimental features
+// Global configuration
+const TELEMETRY_SETTING = new Setting('telemetry', ROOT_SETTING);
+const AST_VIEWER_SETTING = new Setting('astViewer', ROOT_SETTING);
+const GLOBAL_TELEMETRY_SETTING = new Setting('telemetry');
 
-/**
- * This setting is deliberately not in package.json so that it does
- * not appear in the settings ui in vscode itself. If users want to
- * enable experimental features, they can add
- * "codeQl.experimentalFeatures" directly in their vscode settings
- * json file.
- */
-export const EXPERIMENTAL_FEATURES_SETTING = new Setting('experimentalFeatures', ROOT_SETTING);
+export const LOG_TELEMETRY = new Setting('logTelemetry', TELEMETRY_SETTING);
+export const ENABLE_TELEMETRY = new Setting('enableTelemetry', TELEMETRY_SETTING);
 
-/* Advanced setting: used to enable bqrs parsing in the cli instead of in the webview. */
-export const EXPERIMENTAL_BQRS_SETTING = new Setting('experimentalBqrsParsing', ROOT_SETTING);
+export const GLOBAL_ENABLE_TELEMETRY = new Setting('enableTelemetry', GLOBAL_TELEMETRY_SETTING);
 
 // Distribution configuration
-
 const DISTRIBUTION_SETTING = new Setting('cli', ROOT_SETTING);
-const CUSTOM_CODEQL_PATH_SETTING = new Setting('executablePath', DISTRIBUTION_SETTING);
+export const CUSTOM_CODEQL_PATH_SETTING = new Setting('executablePath', DISTRIBUTION_SETTING);
 const INCLUDE_PRERELEASE_SETTING = new Setting('includePrerelease', DISTRIBUTION_SETTING);
 const PERSONAL_ACCESS_TOKEN_SETTING = new Setting('personalAccessToken', DISTRIBUTION_SETTING);
 const QUERY_HISTORY_SETTING = new Setting('queryHistory', ROOT_SETTING);
@@ -66,33 +61,45 @@ const QUERY_HISTORY_FORMAT_SETTING = new Setting('format', QUERY_HISTORY_SETTING
 const DISTRIBUTION_CHANGE_SETTINGS = [CUSTOM_CODEQL_PATH_SETTING, INCLUDE_PRERELEASE_SETTING, PERSONAL_ACCESS_TOKEN_SETTING];
 
 export interface DistributionConfig {
-  customCodeQlPath?: string;
+  readonly customCodeQlPath?: string;
+  updateCustomCodeQlPath: (newPath: string | undefined) => Promise<void>;
   includePrerelease: boolean;
   personalAccessToken?: string;
   ownerName?: string;
   repositoryName?: string;
-  onDidChangeDistributionConfiguration?: Event<void>;
+  onDidChangeConfiguration?: Event<void>;
 }
 
 // Query server configuration
 
 const RUNNING_QUERIES_SETTING = new Setting('runningQueries', ROOT_SETTING);
 const NUMBER_OF_THREADS_SETTING = new Setting('numberOfThreads', RUNNING_QUERIES_SETTING);
+const SAVE_CACHE_SETTING = new Setting('saveCache', RUNNING_QUERIES_SETTING);
+const CACHE_SIZE_SETTING = new Setting('cacheSize', RUNNING_QUERIES_SETTING);
 const TIMEOUT_SETTING = new Setting('timeout', RUNNING_QUERIES_SETTING);
 const MEMORY_SETTING = new Setting('memory', RUNNING_QUERIES_SETTING);
 const DEBUG_SETTING = new Setting('debug', RUNNING_QUERIES_SETTING);
+const RUNNING_TESTS_SETTING = new Setting('runningTests', ROOT_SETTING);
+const RESULTS_DISPLAY_SETTING = new Setting('resultsDisplay', ROOT_SETTING);
+
+export const ADDITIONAL_TEST_ARGUMENTS_SETTING = new Setting('additionalTestArguments', RUNNING_TESTS_SETTING);
+export const NUMBER_OF_TEST_THREADS_SETTING = new Setting('numberOfThreads', RUNNING_TESTS_SETTING);
+export const MAX_QUERIES = new Setting('maxQueries', RUNNING_QUERIES_SETTING);
 export const AUTOSAVE_SETTING = new Setting('autoSave', RUNNING_QUERIES_SETTING);
+export const PAGE_SIZE = new Setting('pageSize', RESULTS_DISPLAY_SETTING);
 
 /** When these settings change, the running query server should be restarted. */
-const QUERY_SERVER_RESTARTING_SETTINGS = [NUMBER_OF_THREADS_SETTING, MEMORY_SETTING, DEBUG_SETTING];
+const QUERY_SERVER_RESTARTING_SETTINGS = [NUMBER_OF_THREADS_SETTING, SAVE_CACHE_SETTING, CACHE_SIZE_SETTING, MEMORY_SETTING, DEBUG_SETTING];
 
 export interface QueryServerConfig {
   codeQlPath: string;
   debug: boolean;
   numThreads: number;
+  saveCache: boolean;
+  cacheSize: number;
   queryMemoryMb?: number;
   timeoutSecs: number;
-  onDidChangeQueryServerConfiguration?: Event<void>;
+  onDidChangeConfiguration?: Event<void>;
 }
 
 /** When these settings change, the query history should be refreshed. */
@@ -100,10 +107,20 @@ const QUERY_HISTORY_SETTINGS = [QUERY_HISTORY_FORMAT_SETTING];
 
 export interface QueryHistoryConfig {
   format: string;
-  onDidChangeQueryHistoryConfiguration: Event<void>;
+  onDidChangeConfiguration: Event<void>;
 }
 
-abstract class ConfigListener extends DisposableObject {
+const CLI_SETTINGS = [ADDITIONAL_TEST_ARGUMENTS_SETTING, NUMBER_OF_TEST_THREADS_SETTING, NUMBER_OF_THREADS_SETTING];
+
+export interface CliConfig {
+  additionalTestArguments: string[];
+  numberTestThreads: number;
+  numberThreads: number;
+  onDidChangeConfiguration?: Event<void>;
+}
+
+
+export abstract class ConfigListener extends DisposableObject {
   protected readonly _onDidChangeConfiguration = this.push(new EventEmitter<void>());
 
   constructor() {
@@ -130,6 +147,10 @@ abstract class ConfigListener extends DisposableObject {
   private updateConfiguration(): void {
     this._onDidChangeConfiguration.fire();
   }
+
+  public get onDidChangeConfiguration(): Event<void> {
+    return this._onDidChangeConfiguration.event;
+  }
 }
 
 export class DistributionConfigListener extends ConfigListener implements DistributionConfig {
@@ -145,8 +166,8 @@ export class DistributionConfigListener extends ConfigListener implements Distri
     return PERSONAL_ACCESS_TOKEN_SETTING.getValue() || undefined;
   }
 
-  public get onDidChangeDistributionConfiguration(): Event<void> {
-    return this._onDidChangeConfiguration.event;
+  public async updateCustomCodeQlPath(newPath: string | undefined) {
+    await CUSTOM_CODEQL_PATH_SETTING.updateValue(newPath, ConfigurationTarget.Global);
   }
 
   protected handleDidChangeConfiguration(e: ConfigurationChangeEvent): void {
@@ -155,7 +176,7 @@ export class DistributionConfigListener extends ConfigListener implements Distri
 }
 
 export class QueryServerConfigListener extends ConfigListener implements QueryServerConfig {
-  private constructor(private _codeQlPath: string) {
+  public constructor(private _codeQlPath = '') {
     super();
   }
 
@@ -180,6 +201,14 @@ export class QueryServerConfigListener extends ConfigListener implements QuerySe
     return NUMBER_OF_THREADS_SETTING.getValue<number>();
   }
 
+  public get saveCache(): boolean {
+    return SAVE_CACHE_SETTING.getValue<boolean>();
+  }
+
+  public get cacheSize(): number {
+    return CACHE_SIZE_SETTING.getValue<number | null>() || 0;
+  }
+
   /** Gets the configured query timeout, in seconds. This looks up the setting at the time of access. */
   public get timeoutSecs(): number {
     return TIMEOUT_SETTING.getValue<number | null>() || 0;
@@ -201,10 +230,6 @@ export class QueryServerConfigListener extends ConfigListener implements QuerySe
     return DEBUG_SETTING.getValue<boolean>();
   }
 
-  public get onDidChangeQueryServerConfiguration(): Event<void> {
-    return this._onDidChangeConfiguration.event;
-  }
-
   protected handleDidChangeConfiguration(e: ConfigurationChangeEvent): void {
     this.handleDidChangeConfigurationForRelevantSettings(QUERY_SERVER_RESTARTING_SETTINGS, e);
   }
@@ -215,11 +240,48 @@ export class QueryHistoryConfigListener extends ConfigListener implements QueryH
     this.handleDidChangeConfigurationForRelevantSettings(QUERY_HISTORY_SETTINGS, e);
   }
 
-  public get onDidChangeQueryHistoryConfiguration(): Event<void> {
-    return this._onDidChangeConfiguration.event;
-  }
-
   public get format(): string {
     return QUERY_HISTORY_FORMAT_SETTING.getValue<string>();
   }
 }
+
+export class CliConfigListener extends ConfigListener implements CliConfig {
+  public get additionalTestArguments(): string[] {
+    return ADDITIONAL_TEST_ARGUMENTS_SETTING.getValue();
+  }
+
+  public get numberTestThreads(): number {
+    return NUMBER_OF_TEST_THREADS_SETTING.getValue();
+  }
+
+  public get numberThreads(): number {
+    return NUMBER_OF_THREADS_SETTING.getValue<number>();
+  }
+
+  protected handleDidChangeConfiguration(e: ConfigurationChangeEvent): void {
+    this.handleDidChangeConfigurationForRelevantSettings(CLI_SETTINGS, e);
+  }
+}
+
+// Enable experimental features
+
+/**
+ * Any settings below are deliberately not in package.json so that
+ * they do not appear in the settings ui in vscode itself. If users
+ * want to enable experimental features, they can add them directly in
+ * their vscode settings json file.
+ */
+
+/**
+ * Enables canary features of this extension. Recommended for all internal users.
+ */
+export const CANARY_FEATURES = new Setting('canary', ROOT_SETTING);
+
+export function isCanary() {
+  return !!CANARY_FEATURES.getValue<boolean>();
+}
+
+/**
+ * Avoids caching in the AST viewer if the user is also a canary user.
+ */
+export const NO_CACHE_AST_VIEWER = new Setting('disableCache', AST_VIEWER_SETTING);

extensions/ql-vscode/src/contextual/astBuilder.ts

@@ -0,0 +1,147 @@
+import { QueryWithResults } from '../run-queries';
+import { CodeQLCliServer } from '../cli';
+import { DecodedBqrsChunk, BqrsId, EntityValue } from '../pure/bqrs-cli-types';
+import { DatabaseItem } from '../databases';
+import { ChildAstItem, AstItem } from '../astViewer';
+import fileRangeFromURI from './fileRangeFromURI';
+
+/**
+ * A class that wraps a tree of QL results from a query that
+ * has an @kind of graph
+ */
+export default class AstBuilder {
+
+  private roots: AstItem[] | undefined;
+  private bqrsPath: string;
+  constructor(
+    queryResults: QueryWithResults,
+    private cli: CodeQLCliServer,
+    public db: DatabaseItem,
+    public fileName: string
+  ) {
+    this.bqrsPath = queryResults.query.resultsPaths.resultsPath;
+  }
+
+  async getRoots(): Promise<AstItem[]> {
+    if (!this.roots) {
+      this.roots = await this.parseRoots();
+    }
+    return this.roots;
+  }
+
+  private async parseRoots(): Promise<AstItem[]> {
+    const options = { entities: ['id', 'url', 'string'] };
+    const [nodeTuples, edgeTuples, graphProperties] = await Promise.all([
+      await this.cli.bqrsDecode(this.bqrsPath, 'nodes', options),
+      await this.cli.bqrsDecode(this.bqrsPath, 'edges', options),
+      await this.cli.bqrsDecode(this.bqrsPath, 'graphProperties', options),
+    ]);
+
+    if (!this.isValidGraph(graphProperties)) {
+      throw new Error('AST is invalid');
+    }
+
+    const idToItem = new Map<BqrsId, AstItem>();
+    const parentToChildren = new Map<BqrsId, BqrsId[]>();
+    const childToParent = new Map<BqrsId, BqrsId>();
+    const astOrder = new Map<BqrsId, number>();
+    const edgeLabels = new Map<BqrsId, string>();
+    const roots = [];
+
+    // Build up the parent-child relationships
+    edgeTuples.tuples.forEach(tuple => {
+      const [source, target, tupleType, value] = tuple as [EntityValue, EntityValue, string, string];
+      const sourceId = source.id!;
+      const targetId = target.id!;
+
+      switch (tupleType) {
+        case 'semmle.order':
+          astOrder.set(targetId, Number(value));
+          break;
+
+        case 'semmle.label': {
+          childToParent.set(targetId, sourceId);
+          let children = parentToChildren.get(sourceId);
+          if (!children) {
+            parentToChildren.set(sourceId, children = []);
+          }
+          children.push(targetId);
+
+          // ignore values that indicate a numeric order.
+          if (!Number.isFinite(Number(value))) {
+            edgeLabels.set(targetId, value);
+          }
+          break;
+        }
+
+        default:
+        // ignore other tupleTypes since they are not needed by the ast viewer
+      }
+    });
+
+    // populate parents and children
+    nodeTuples.tuples.forEach(tuple => {
+      const [entity, tupleType, value] = tuple as [EntityValue, string, string];
+      const id = entity.id!;
+
+      switch (tupleType) {
+        case 'semmle.order':
+          astOrder.set(id, Number(value));
+          break;
+
+        case 'semmle.label': {
+          // If an edge label exists, include it and separate from the node label using ':'
+          const nodeLabel = value ?? entity.label;
+          const edgeLabel = edgeLabels.get(id);
+          const label = [edgeLabel, nodeLabel].filter(e => e).join(': ');
+          const item = {
+            id,
+            label,
+            location: entity.url,
+            fileLocation: fileRangeFromURI(entity.url, this.db),
+            children: [] as ChildAstItem[],
+            order: Number.MAX_SAFE_INTEGER
+          };
+
+          idToItem.set(id, item);
+          const parent = idToItem.get(childToParent.has(id) ? childToParent.get(id)! : -1);
+
+          if (parent) {
+            const astItem = item as ChildAstItem;
+            astItem.parent = parent;
+            parent.children.push(astItem);
+          }
+          const children = parentToChildren.has(id) ? parentToChildren.get(id)! : [];
+          children.forEach(childId => {
+            const child = idToItem.get(childId) as ChildAstItem | undefined;
+            if (child) {
+              child.parent = item;
+              item.children.push(child);
+            }
+          });
+          break;
+        }
+
+        default:
+        // ignore other tupleTypes since they are not needed by the ast viewer
+      }
+    });
+
+    // find the roots and add the order
+    for (const [, item] of idToItem) {
+      item.order = astOrder.has(item.id)
+        ? astOrder.get(item.id)!
+        : Number.MAX_SAFE_INTEGER;
+
+      if (!('parent' in item)) {
+        roots.push(item);
+      }
+    }
+    return roots;
+  }
+
+  private isValidGraph(graphProperties: DecodedBqrsChunk) {
+    const tuple = graphProperties?.tuples?.find(t => t[0] === 'semmle.graphKind');
+    return tuple?.[1] === 'tree';
+  }
+}

extensions/ql-vscode/src/contextual/fileRangeFromURI.ts

@@ -0,0 +1,31 @@
+import * as vscode from 'vscode';
+
+import { UrlValue, LineColumnLocation } from '../pure/bqrs-cli-types';
+import { isEmptyPath } from '../pure/bqrs-utils';
+import { DatabaseItem } from '../databases';
+
+
+export default function fileRangeFromURI(uri: UrlValue | undefined, db: DatabaseItem): vscode.Location | undefined {
+  if (!uri || typeof uri === 'string') {
+    return undefined;
+  } else if ('startOffset' in uri) {
+    return undefined;
+  } else {
+    const loc = uri as LineColumnLocation;
+    if (isEmptyPath(loc.uri)) {
+      return undefined;
+    }
+    const range = new vscode.Range(Math.max(0, (loc.startLine || 0) - 1),
+      Math.max(0, (loc.startColumn || 0) - 1),
+      Math.max(0, (loc.endLine || 0) - 1),
+      Math.max(0, (loc.endColumn || 0)));
+    try {
+      if (uri.uri.startsWith('file:')) {
+        return new vscode.Location(db.resolveSourceFile(uri.uri), range);
+      }
+      return undefined;
+    } catch (e) {
+      return undefined;
+    }
+  }
+}

extensions/ql-vscode/src/contextual/keyType.ts

@@ -0,0 +1,37 @@
+export enum KeyType {
+  DefinitionQuery = 'DefinitionQuery',
+  ReferenceQuery = 'ReferenceQuery',
+  PrintAstQuery = 'PrintAstQuery',
+}
+
+export function tagOfKeyType(keyType: KeyType): string {
+  switch (keyType) {
+    case KeyType.DefinitionQuery:
+      return 'ide-contextual-queries/local-definitions';
+    case KeyType.ReferenceQuery:
+      return 'ide-contextual-queries/local-references';
+    case KeyType.PrintAstQuery:
+      return 'ide-contextual-queries/print-ast';
+  }
+}
+
+export function nameOfKeyType(keyType: KeyType): string {
+  switch (keyType) {
+    case KeyType.DefinitionQuery:
+      return 'definitions';
+    case KeyType.ReferenceQuery:
+      return 'references';
+    case KeyType.PrintAstQuery:
+      return 'print AST';
+  }
+}
+
+export function kindOfKeyType(keyType: KeyType): string {
+  switch (keyType) {
+    case KeyType.DefinitionQuery:
+    case KeyType.ReferenceQuery:
+      return 'definitions';
+    case KeyType.PrintAstQuery:
+      return 'graph';
+  }
+}

extensions/ql-vscode/src/contextual/locationFinder.ts

@@ -0,0 +1,124 @@
+import * as vscode from 'vscode';
+
+import { decodeSourceArchiveUri, encodeArchiveBasePath } from '../archive-filesystem-provider';
+import { ColumnKindCode, EntityValue, getResultSetSchema, ResultSetSchema } from '../pure/bqrs-cli-types';
+import { CodeQLCliServer } from '../cli';
+import { DatabaseManager, DatabaseItem } from '../databases';
+import fileRangeFromURI from './fileRangeFromURI';
+import * as messages from '../pure/messages';
+import { QueryServerClient } from '../queryserver-client';
+import { QueryWithResults, compileAndRunQueryAgainstDatabase } from '../run-queries';
+import { ProgressCallback } from '../commandRunner';
+import { KeyType } from './keyType';
+import { qlpackOfDatabase, resolveQueries } from './queryResolver';
+
+const SELECT_QUERY_NAME = '#select';
+export const TEMPLATE_NAME = 'selectedSourceFile';
+
+export interface FullLocationLink extends vscode.LocationLink {
+  originUri: vscode.Uri;
+}
+
+/**
+ * This function executes a contextual query inside a given database, filters, and converts
+ * the results into source locations. This function is the workhorse for all search-based
+ * contextual queries like find references and find definitions.
+ *
+ * @param cli The cli server
+ * @param qs The query server client
+ * @param dbm The database manager
+ * @param uriString The selected source file and location
+ * @param keyType The contextual query type to run
+ * @param progress A progress callback
+ * @param token A CancellationToken
+ * @param filter A function that will filter extraneous results
+ */
+export async function getLocationsForUriString(
+  cli: CodeQLCliServer,
+  qs: QueryServerClient,
+  dbm: DatabaseManager,
+  uriString: string,
+  keyType: KeyType,
+  progress: ProgressCallback,
+  token: vscode.CancellationToken,
+  filter: (src: string, dest: string) => boolean
+): Promise<FullLocationLink[]> {
+  const uri = decodeSourceArchiveUri(vscode.Uri.parse(uriString, true));
+  const sourceArchiveUri = encodeArchiveBasePath(uri.sourceArchiveZipPath);
+
+  const db = dbm.findDatabaseItemBySourceArchive(sourceArchiveUri);
+  if (!db) {
+    return [];
+  }
+
+  const qlpack = await qlpackOfDatabase(cli, db);
+  const templates = createTemplates(uri.pathWithinSourceArchive);
+
+  const links: FullLocationLink[] = [];
+  for (const query of await resolveQueries(cli, qlpack, keyType)) {
+    const results = await compileAndRunQueryAgainstDatabase(
+      cli,
+      qs,
+      db,
+      false,
+      vscode.Uri.file(query),
+      progress,
+      token,
+      templates
+    );
+
+    if (results.result.resultType == messages.QueryResultType.SUCCESS) {
+      links.push(...await getLinksFromResults(results, cli, db, filter));
+    }
+  }
+  return links;
+}
+
+async function getLinksFromResults(
+  results: QueryWithResults,
+  cli: CodeQLCliServer,
+  db: DatabaseItem,
+  filter: (srcFile: string, destFile: string) => boolean
+): Promise<FullLocationLink[]> {
+  const localLinks: FullLocationLink[] = [];
+  const bqrsPath = results.query.resultsPaths.resultsPath;
+  const info = await cli.bqrsInfo(bqrsPath);
+  const selectInfo = getResultSetSchema(SELECT_QUERY_NAME, info);
+  if (isValidSelect(selectInfo)) {
+    // TODO: Page this
+    const allTuples = await cli.bqrsDecode(bqrsPath, SELECT_QUERY_NAME);
+    for (const tuple of allTuples.tuples) {
+      const [src, dest] = tuple as [EntityValue, EntityValue];
+      const srcFile = src.url && fileRangeFromURI(src.url, db);
+      const destFile = dest.url && fileRangeFromURI(dest.url, db);
+      if (srcFile && destFile && filter(srcFile.uri.toString(), destFile.uri.toString())) {
+        localLinks.push({
+          targetRange: destFile.range,
+          targetUri: destFile.uri,
+          originSelectionRange: srcFile.range,
+          originUri: srcFile.uri
+        });
+      }
+    }
+  }
+  return localLinks;
+}
+
+function createTemplates(path: string): messages.TemplateDefinitions {
+  return {
+    [TEMPLATE_NAME]: {
+      values: {
+        tuples: [[{
+          stringValue: path
+        }]]
+      }
+    }
+  };
+}
+
+function isValidSelect(selectInfo: ResultSetSchema | undefined) {
+  return selectInfo && selectInfo.columns.length == 3
+    && selectInfo.columns[0].kind == ColumnKindCode.ENTITY
+    && selectInfo.columns[1].kind == ColumnKindCode.ENTITY
+    && selectInfo.columns[2].kind == ColumnKindCode.STRING;
+}

extensions/ql-vscode/src/contextual/queryResolver.ts

@@ -0,0 +1,48 @@
+import * as fs from 'fs-extra';
+import * as yaml from 'js-yaml';
+import * as tmp from 'tmp-promise';
+
+import * as helpers from '../helpers';
+import {
+  KeyType,
+  kindOfKeyType,
+  nameOfKeyType,
+  tagOfKeyType
+} from './keyType';
+import { CodeQLCliServer } from '../cli';
+import { DatabaseItem } from '../databases';
+
+export async function qlpackOfDatabase(cli: CodeQLCliServer, db: DatabaseItem): Promise<string> {
+  if (db.contents === undefined) {
+    throw new Error('Database is invalid and cannot infer QLPack.');
+  }
+  const datasetPath = db.contents.datasetUri.fsPath;
+  const dbscheme = await helpers.getPrimaryDbscheme(datasetPath);
+  return await helpers.getQlPackForDbscheme(cli, dbscheme);
+}
+
+
+export async function resolveQueries(cli: CodeQLCliServer, qlpack: string, keyType: KeyType): Promise<string[]> {
+  const suiteFile = (await tmp.file({
+    postfix: '.qls'
+  })).path;
+  const suiteYaml = {
+    qlpack,
+    include: {
+      kind: kindOfKeyType(keyType),
+      'tags contain': tagOfKeyType(keyType)
+    }
+  };
+  await fs.writeFile(suiteFile, yaml.safeDump(suiteYaml), 'utf8');
+
+  const queries = await cli.resolveQueriesInSuite(suiteFile, helpers.getOnDiskWorkspaceFolders());
+  if (queries.length === 0) {
+    helpers.showAndLogErrorMessage(
+      `No ${nameOfKeyType(keyType)} queries (tagged "${tagOfKeyType(keyType)}") could be found in the current library path. \
+      Try upgrading the CodeQL libraries. If that doesn't work, then ${nameOfKeyType(keyType)} queries are not yet available \
+      for this language.`
+    );
+    throw new Error(`Couldn't find any queries tagged ${tagOfKeyType(keyType)} for qlpack ${qlpack}`);
+  }
+  return queries;
+}

extensions/ql-vscode/src/contextual/templateProvider.ts

@@ -0,0 +1,209 @@
+import {
+  CancellationToken,
+  DefinitionProvider,
+  Location,
+  LocationLink,
+  Position,
+  ProgressLocation,
+  ReferenceContext,
+  ReferenceProvider,
+  TextDocument,
+  Uri
+} from 'vscode';
+
+import { decodeSourceArchiveUri, encodeArchiveBasePath, zipArchiveScheme } from '../archive-filesystem-provider';
+import { CodeQLCliServer } from '../cli';
+import { DatabaseManager } from '../databases';
+import { CachedOperation } from '../helpers';
+import { ProgressCallback, withProgress } from '../commandRunner';
+import * as messages from '../pure/messages';
+import { QueryServerClient } from '../queryserver-client';
+import { compileAndRunQueryAgainstDatabase, QueryWithResults } from '../run-queries';
+import AstBuilder from './astBuilder';
+import {
+  KeyType,
+} from './keyType';
+import { FullLocationLink, getLocationsForUriString, TEMPLATE_NAME } from './locationFinder';
+import { qlpackOfDatabase, resolveQueries } from './queryResolver';
+import { isCanary, NO_CACHE_AST_VIEWER } from '../config';
+
+/**
+ * Run templated CodeQL queries to find definitions and references in
+ * source-language files. We may eventually want to find a way to
+ * generalize this to other custom queries, e.g. showing dataflow to
+ * or from a selected identifier.
+ */
+
+export class TemplateQueryDefinitionProvider implements DefinitionProvider {
+  private cache: CachedOperation<LocationLink[]>;
+
+  constructor(
+    private cli: CodeQLCliServer,
+    private qs: QueryServerClient,
+    private dbm: DatabaseManager,
+  ) {
+    this.cache = new CachedOperation<LocationLink[]>(this.getDefinitions.bind(this));
+  }
+
+  async provideDefinition(document: TextDocument, position: Position, _token: CancellationToken): Promise<LocationLink[]> {
+    const fileLinks = await this.cache.get(document.uri.toString());
+    const locLinks: LocationLink[] = [];
+    for (const link of fileLinks) {
+      if (link.originSelectionRange!.contains(position)) {
+        locLinks.push(link);
+      }
+    }
+    return locLinks;
+  }
+
+  private async getDefinitions(uriString: string): Promise<LocationLink[]> {
+    return withProgress({
+      location: ProgressLocation.Notification,
+      cancellable: true,
+      title: 'Finding definitions'
+    }, async (progress, token) => {
+      return getLocationsForUriString(
+        this.cli,
+        this.qs,
+        this.dbm,
+        uriString,
+        KeyType.DefinitionQuery,
+        progress,
+        token,
+        (src, _dest) => src === uriString
+      );
+    });
+  }
+}
+
+export class TemplateQueryReferenceProvider implements ReferenceProvider {
+  private cache: CachedOperation<FullLocationLink[]>;
+
+  constructor(
+    private cli: CodeQLCliServer,
+    private qs: QueryServerClient,
+    private dbm: DatabaseManager,
+  ) {
+    this.cache = new CachedOperation<FullLocationLink[]>(this.getReferences.bind(this));
+  }
+
+  async provideReferences(
+    document: TextDocument,
+    position: Position,
+    _context: ReferenceContext,
+    _token: CancellationToken
+  ): Promise<Location[]> {
+    const fileLinks = await this.cache.get(document.uri.toString());
+    const locLinks: Location[] = [];
+    for (const link of fileLinks) {
+      if (link.targetRange!.contains(position)) {
+        locLinks.push({ range: link.originSelectionRange!, uri: link.originUri });
+      }
+    }
+    return locLinks;
+  }
+
+  private async getReferences(uriString: string): Promise<FullLocationLink[]> {
+    return withProgress({
+      location: ProgressLocation.Notification,
+      cancellable: true,
+      title: 'Finding references'
+    }, async (progress, token) => {
+      return getLocationsForUriString(
+        this.cli,
+        this.qs,
+        this.dbm,
+        uriString,
+        KeyType.DefinitionQuery,
+        progress,
+        token,
+        (src, _dest) => src === uriString
+      );
+    });
+  }
+}
+
+export class TemplatePrintAstProvider {
+  private cache: CachedOperation<QueryWithResults>;
+
+  constructor(
+    private cli: CodeQLCliServer,
+    private qs: QueryServerClient,
+    private dbm: DatabaseManager,
+  ) {
+    this.cache = new CachedOperation<QueryWithResults>(this.getAst.bind(this));
+  }
+
+  async provideAst(
+    progress: ProgressCallback,
+    token: CancellationToken,
+    document?: TextDocument
+  ): Promise<AstBuilder | undefined> {
+    if (!document) {
+      throw new Error('Cannot view the AST. Please select a valid source file inside a CodeQL database.');
+    }
+    const queryResults = this.shouldCache()
+      ? await this.cache.get(document.uri.toString(), progress, token)
+      : await this.getAst(document.uri.toString(), progress, token);
+
+    return new AstBuilder(
+      queryResults, this.cli,
+      this.dbm.findDatabaseItem(Uri.parse(queryResults.database.databaseUri!, true))!,
+      document.fileName
+    );
+  }
+
+  private shouldCache() {
+    return !(isCanary() && NO_CACHE_AST_VIEWER.getValue<boolean>());
+  }
+
+  private async getAst(
+    uriString: string,
+    progress: ProgressCallback,
+    token: CancellationToken
+  ): Promise<QueryWithResults> {
+    const uri = Uri.parse(uriString, true);
+    if (uri.scheme !== zipArchiveScheme) {
+      throw new Error('Cannot view the AST. Please select a valid source file inside a CodeQL database.');
+    }
+
+    const zippedArchive = decodeSourceArchiveUri(uri);
+    const sourceArchiveUri = encodeArchiveBasePath(zippedArchive.sourceArchiveZipPath);
+    const db = this.dbm.findDatabaseItemBySourceArchive(sourceArchiveUri);
+
+    if (!db) {
+      throw new Error('Can\'t infer database from the provided source.');
+    }
+
+    const qlpack = await qlpackOfDatabase(this.cli, db);
+    const queries = await resolveQueries(this.cli, qlpack, KeyType.PrintAstQuery);
+    if (queries.length > 1) {
+      throw new Error('Found multiple Print AST queries. Can\'t continue');
+    }
+    if (queries.length === 0) {
+      throw new Error('Did not find any Print AST queries. Can\'t continue');
+    }
+
+    const query = queries[0];
+    const templates: messages.TemplateDefinitions = {
+      [TEMPLATE_NAME]: {
+        values: {
+          tuples: [[{
+            stringValue: zippedArchive.pathWithinSourceArchive
+          }]]
+        }
+      }
+    };
+
+    return await compileAndRunQueryAgainstDatabase(
+      this.cli,
+      this.qs,
+      db,
+      false,
+      Uri.file(query),
+      progress,
+      token,
+      templates
+    );
+  }
+}

extensions/ql-vscode/src/databaseFetcher.ts

@@ -1,103 +1,234 @@
-import * as fetch from "node-fetch";
-import * as unzipper from "unzipper";
-import { Uri, ProgressOptions, ProgressLocation, commands, window } from "vscode";
-import * as fs from "fs-extra";
-import * as path from "path";
-import { DatabaseManager } from "./databases";
-import { ProgressCallback, showAndLogErrorMessage, withProgress } from "./helpers";
+import fetch, { Response } from 'node-fetch';
+import * as unzipper from 'unzipper';
+import { zip } from 'zip-a-folder';
+import {
+  Uri,
+  CancellationToken,
+  commands,
+  window,
+} from 'vscode';
+import * as fs from 'fs-extra';
+import * as path from 'path';
 
-export default async function promptFetchDatabase(dbm: DatabaseManager, storagePath: string) {
-  try {
-    const databaseUrl = await window.showInputBox({
-      prompt: 'Enter URL of zipfile of database to download'
-    });
+import { DatabaseManager, DatabaseItem } from './databases';
+import {
+  showAndLogInformationMessage,
+} from './helpers';
+import {
+  reportStreamProgress,
+  ProgressCallback,
+} from './commandRunner';
+import { logger } from './logging';
+import { tmpDir } from './run-queries';
 
+/**
+ * Prompts a user to fetch a database from a remote location. Database is assumed to be an archive file.
+ *
+ * @param databaseManager the DatabaseManager
+ * @param storagePath where to store the unzipped database.
+ */
+export async function promptImportInternetDatabase(
+  databaseManager: DatabaseManager,
+  storagePath: string,
+  progress: ProgressCallback,
+  token: CancellationToken,
+): Promise<DatabaseItem | undefined> {
+  const databaseUrl = await window.showInputBox({
+    prompt: 'Enter URL of zipfile of database to download',
+  });
+  if (!databaseUrl) {
+    return;
+  }
+
+  validateHttpsUrl(databaseUrl);
+
+  const item = await databaseArchiveFetcher(
+    databaseUrl,
+    databaseManager,
+    storagePath,
+    progress,
+    token
+  );
+
+  if (item) {
+    commands.executeCommand('codeQLDatabases.focus');
+    showAndLogInformationMessage('Database downloaded and imported successfully.');
+  }
+  return item;
+
+}
+
+/**
+ * Prompts a user to fetch a database from lgtm.
+ * User enters a project url and then the user is asked which language
+ * to download (if there is more than one)
+ *
+ * @param databaseManager the DatabaseManager
+ * @param storagePath where to store the unzipped database.
+ */
+export async function promptImportLgtmDatabase(
+  databaseManager: DatabaseManager,
+  storagePath: string,
+  progress: ProgressCallback,
+  token: CancellationToken
+): Promise<DatabaseItem | undefined> {
+  const lgtmUrl = await window.showInputBox({
+    prompt:
+      'Enter the project slug or URL on LGTM (e.g., g/github/codeql or https://lgtm.com/projects/g/github/codeql)',
+  });
+  if (!lgtmUrl) {
+    return;
+  }
+
+  if (looksLikeLgtmUrl(lgtmUrl)) {
+    const databaseUrl = await convertToDatabaseUrl(lgtmUrl);
     if (databaseUrl) {
-      validateUrl(databaseUrl);
-
-      const progressOptions: ProgressOptions = {
-        location: ProgressLocation.Notification,
-        title: 'Adding database from URL',
-        cancellable: false,
-      };
-      await withProgress(progressOptions, async progress => await databaseFetcher(databaseUrl, dbm, storagePath, progress));
-      commands.executeCommand('codeQLDatabases.focus');
+      const item = await databaseArchiveFetcher(
+        databaseUrl,
+        databaseManager,
+        storagePath,
+        progress,
+        token
+      );
+      if (item) {
+        commands.executeCommand('codeQLDatabases.focus');
+        showAndLogInformationMessage('Database downloaded and imported successfully.');
+      }
+      return item;
     }
+  } else {
+    throw new Error(`Invalid LGTM URL: ${lgtmUrl}`);
+  }
+  return;
+}
+
+/**
+ * Imports a database from a local archive.
+ *
+ * @param databaseUrl the file url of the archive to import
+ * @param databaseManager the DatabaseManager
+ * @param storagePath where to store the unzipped database.
+ */
+export async function importArchiveDatabase(
+  databaseUrl: string,
+  databaseManager: DatabaseManager,
+  storagePath: string,
+  progress: ProgressCallback,
+  token: CancellationToken,
+): Promise<DatabaseItem | undefined> {
+  try {
+    const item = await databaseArchiveFetcher(
+      databaseUrl,
+      databaseManager,
+      storagePath,
+      progress,
+      token
+    );
+    if (item) {
+      commands.executeCommand('codeQLDatabases.focus');
+      showAndLogInformationMessage('Database unzipped and imported successfully.');
+    }
+    return item;
   } catch (e) {
-    showAndLogErrorMessage(e.message);
+    if (e.message.includes('unexpected end of file')) {
+      throw new Error('Database is corrupt or too large. Try unzipping outside of VS Code and importing the unzipped folder instead.');
+    } else {
+      // delegate
+      throw e;
+    }
   }
 }
 
-async function databaseFetcher(
+/**
+ * Fetches an archive database. The database might be on the internet
+ * or in the local filesystem.
+ *
+ * @param databaseUrl URL from which to grab the database
+ * @param databaseManager the DatabaseManager
+ * @param storagePath where to store the unzipped database.
+ * @param progress callback to send progress messages to
+ * @param token cancellation token
+ */
+async function databaseArchiveFetcher(
   databaseUrl: string,
-  databasesManager: DatabaseManager,
+  databaseManager: DatabaseManager,
   storagePath: string,
-  progressCallback: ProgressCallback
-): Promise<void> {
-  progressCallback({
-    maxStep: 3,
-    message: 'Downloading database',
-    step: 1
+  progress: ProgressCallback,
+  token: CancellationToken
+): Promise<DatabaseItem> {
+  progress({
+    message: 'Getting database',
+    step: 1,
+    maxStep: 4,
   });
   if (!storagePath) {
-    throw new Error("No storage path specified.");
+    throw new Error('No storage path specified.');
   }
+  await fs.ensureDir(storagePath);
   const unzipPath = await getStorageFolder(storagePath, databaseUrl);
 
-  const response = await fetch.default(databaseUrl);
-  const unzipStream = unzipper.Extract({
-    path: unzipPath
-  });
-  progressCallback({
-    maxStep: 3,
-    message: 'Unzipping database',
-    step: 2
-  });
-  await new Promise((resolve, reject) => {
-    response.body.on('error', reject);
-    unzipStream.on('error', reject);
-    unzipStream.on('close', resolve);
-    response.body.pipe(unzipStream);
-  });
-  progressCallback({
-    maxStep: 3,
+  if (isFile(databaseUrl)) {
+    await readAndUnzip(databaseUrl, unzipPath, progress);
+  } else {
+    await fetchAndUnzip(databaseUrl, unzipPath, progress);
+  }
+
+  progress({
     message: 'Opening database',
-    step: 3
+    step: 3,
+    maxStep: 4,
   });
 
-  // if there is a single directory inside, then assume that's what we want to import
-  const dirs = await fs.readdir(unzipPath);
-  const dbPath = dirs?.length === 1 && (await fs.stat(path.join(unzipPath, dirs[0]))).isDirectory
-    ? path.join(unzipPath, dirs[0])
-    : unzipPath;
+  // find the path to the database. The actual database might be in a sub-folder
+  const dbPath = await findDirWithFile(
+    unzipPath,
+    '.dbinfo',
+    'codeql-database.yml'
+  );
+  if (dbPath) {
+    progress({
+      message: 'Validating and fixing source location',
+      step: 4,
+      maxStep: 4,
+    });
+    await ensureZippedSourceLocation(dbPath);
 
-  // might need to upgrade before importing...
-  const item = await databasesManager.openDatabase(Uri.parse(dbPath));
-  databasesManager.setCurrentDatabaseItem(item);
+    const item = await databaseManager.openDatabase(progress, token, Uri.file(dbPath));
+    await databaseManager.setCurrentDatabaseItem(item);
+    return item;
+  } else {
+    throw new Error('Database not found in archive.');
+  }
 }
 
 async function getStorageFolder(storagePath: string, urlStr: string) {
+  // we need to generate a folder name for the unzipped archive,
+  // this needs to be human readable since we may use this name as the initial
+  // name for the database
   const url = Uri.parse(urlStr);
-  let lastName = path.basename(url.path).substring(0, 255);
-  if (lastName.endsWith(".zip")) {
+  // MacOS has a max filename length of 255
+  // and remove a few extra chars in case we need to add a counter at the end.
+  let lastName = path.basename(url.path).substring(0, 250);
+  if (lastName.endsWith('.zip')) {
     lastName = lastName.substring(0, lastName.length - 4);
   }
 
   const realpath = await fs.realpath(storagePath);
   let folderName = path.join(realpath, lastName);
+
+  // avoid overwriting existing folders
   let counter = 0;
   while (await fs.pathExists(folderName)) {
     counter++;
     folderName = path.join(realpath, `${lastName}-${counter}`);
     if (counter > 100) {
-      throw new Error("Could not find a unique name for downloaded database.");
+      throw new Error('Could not find a unique name for downloaded database.');
     }
   }
   return folderName;
 }
 
-
-function validateUrl(databaseUrl: string) {
+function validateHttpsUrl(databaseUrl: string) {
   let uri;
   try {
     uri = Uri.parse(databaseUrl, true);
@@ -109,3 +240,238 @@ function validateUrl(databaseUrl: string) {
     throw new Error('Must use https for downloading a database.');
   }
 }
+
+async function readAndUnzip(
+  zipUrl: string,
+  unzipPath: string,
+  progress?: ProgressCallback
+) {
+  // TODO: Providing progress as the file is unzipped is currently blocked
+  // on https://github.com/ZJONSSON/node-unzipper/issues/222
+  const zipFile = Uri.parse(zipUrl).fsPath;
+  progress?.({
+    maxStep: 10,
+    step: 9,
+    message: `Unzipping into ${path.basename(unzipPath)}`
+  });
+  // Must get the zip central directory since streaming the
+  // zip contents may not have correct local file headers.
+  // Instead, we can only rely on the central directory.
+  const directory = await unzipper.Open.file(zipFile);
+  await directory.extract({ path: unzipPath });
+}
+
+async function fetchAndUnzip(
+  databaseUrl: string,
+  unzipPath: string,
+  progress?: ProgressCallback
+) {
+  // Although it is possible to download and stream directly to an unzipped directory,
+  // we need to avoid this for two reasons. The central directory is located at the
+  // end of the zip file. It is the source of truth of the content locations. Individual
+  // file headers may be incorrect. Additionally, saving to file first will reduce memory
+  // pressure compared with unzipping while downloading the archive.
+
+  const archivePath = path.join(tmpDir.name, `archive-${Date.now()}.zip`);
+
+  progress?.({
+    maxStep: 3,
+    message: 'Downloading database',
+    step: 1,
+  });
+
+  const response = await checkForFailingResponse(await fetch(databaseUrl));
+  const archiveFileStream = fs.createWriteStream(archivePath);
+
+  const contentLength = response.headers.get('content-length');
+  const totalNumBytes = contentLength ? parseInt(contentLength, 10) : undefined;
+  reportStreamProgress(response.body, 'Downloading database', totalNumBytes, progress);
+
+  await new Promise((resolve, reject) =>
+    response.body.pipe(archiveFileStream)
+      .on('finish', resolve)
+      .on('error', reject)
+  );
+
+  await readAndUnzip(Uri.file(archivePath).toString(true), unzipPath, progress);
+
+  // remove archivePath eagerly since these archives can be large.
+  await fs.remove(archivePath);
+}
+
+async function checkForFailingResponse(response: Response): Promise<Response | never> {
+  if (response.ok) {
+    return response;
+  }
+
+  // An error downloading the database. Attempt to extract the resaon behind it.
+  const text = await response.text();
+  let msg: string;
+  try {
+    const obj = JSON.parse(text);
+    msg = obj.error || obj.message || obj.reason || JSON.stringify(obj, null, 2);
+  } catch (e) {
+    msg = text;
+  }
+  throw new Error(`Error downloading database.\n\nReason: ${msg}`);
+}
+
+function isFile(databaseUrl: string) {
+  return Uri.parse(databaseUrl).scheme === 'file';
+}
+
+/**
+ * Recursively looks for a file in a directory. If the file exists, then returns the directory containing the file.
+ *
+ * @param dir The directory to search
+ * @param toFind The file to recursively look for in this directory
+ *
+ * @returns the directory containing the file, or undefined if not found.
+ */
+// exported for testing
+export async function findDirWithFile(
+  dir: string,
+  ...toFind: string[]
+): Promise<string | undefined> {
+  if (!(await fs.stat(dir)).isDirectory()) {
+    return;
+  }
+  const files = await fs.readdir(dir);
+  if (toFind.some((file) => files.includes(file))) {
+    return dir;
+  }
+  for (const file of files) {
+    const newPath = path.join(dir, file);
+    const result = await findDirWithFile(newPath, ...toFind);
+    if (result) {
+      return result;
+    }
+  }
+  return;
+}
+
+/**
+ * The URL pattern is https://lgtm.com/projects/{provider}/{org}/{name}/{irrelevant-subpages}.
+ * There are several possibilities for the provider: in addition to GitHub.com (g),
+ * LGTM currently hosts projects from Bitbucket (b), GitLab (gl) and plain git (git).
+ *
+ * This function accepts any url that matches the pattern above. It also accepts the
+ * raw project slug, e.g., `g/myorg/myproject`
+ *
+ * After the `{provider}/{org}/{name}` path components, there may be the components
+ * related to sub pages.
+ *
+ * @param lgtmUrl The URL to the lgtm project
+ *
+ * @return true if this looks like an LGTM project url
+ */
+// exported for testing
+export function looksLikeLgtmUrl(lgtmUrl: string | undefined): lgtmUrl is string {
+  if (!lgtmUrl) {
+    return false;
+  }
+
+  if (convertRawLgtmSlug(lgtmUrl)) {
+    return true;
+  }
+
+  try {
+    const uri = Uri.parse(lgtmUrl, true);
+    if (uri.scheme !== 'https') {
+      return false;
+    }
+
+    if (uri.authority !== 'lgtm.com' && uri.authority !== 'www.lgtm.com') {
+      return false;
+    }
+
+    const paths = uri.path.split('/').filter((segment) => segment);
+    return paths.length >= 4 && paths[0] === 'projects';
+  } catch (e) {
+    return false;
+  }
+}
+
+function convertRawLgtmSlug(maybeSlug: string): string | undefined {
+  if (!maybeSlug) {
+    return;
+  }
+  const segments = maybeSlug.split('/');
+  const providers = ['g', 'gl', 'b', 'git'];
+  if (segments.length === 3 && providers.includes(segments[0])) {
+    return `https://lgtm.com/projects/${maybeSlug}`;
+  }
+  return;
+}
+
+// exported for testing
+export async function convertToDatabaseUrl(lgtmUrl: string) {
+  try {
+    lgtmUrl = convertRawLgtmSlug(lgtmUrl) || lgtmUrl;
+
+    const uri = Uri.parse(lgtmUrl, true);
+    const paths = ['api', 'v1.0'].concat(
+      uri.path.split('/').filter((segment) => segment)
+    ).slice(0, 6);
+    const projectUrl = `https://lgtm.com/${paths.join('/')}`;
+    const projectResponse = await fetch(projectUrl);
+    const projectJson = await projectResponse.json();
+
+    if (projectJson.code === 404) {
+      throw new Error();
+    }
+
+    const language = await promptForLanguage(projectJson);
+    if (!language) {
+      return;
+    }
+    return `https://lgtm.com/${[
+      'api',
+      'v1.0',
+      'snapshots',
+      projectJson.id,
+      language,
+    ].join('/')}`;
+  } catch (e) {
+    logger.log(`Error: ${e.message}`);
+    throw new Error(`Invalid LGTM URL: ${lgtmUrl}`);
+  }
+}
+
+async function promptForLanguage(
+  projectJson: any
+): Promise<string | undefined> {
+  if (!projectJson?.languages?.length) {
+    return;
+  }
+  if (projectJson.languages.length === 1) {
+    return projectJson.languages[0].language;
+  }
+
+  return await window.showQuickPick(
+    projectJson.languages.map((lang: { language: string }) => lang.language), {
+    placeHolder: 'Select the database language to download:'
+  }
+  );
+}
+
+/**
+ * Databases created by the old odasa tool will not have a zipped
+ * source location. However, this extension works better if sources
+ * are zipped.
+ *
+ * This function ensures that the source location is zipped. If the
+ * `src` folder exists and the `src.zip` file does not, the `src`
+ * folder will be zipped and then deleted.
+ *
+ * @param databasePath The full path to the unzipped database
+ */
+async function ensureZippedSourceLocation(databasePath: string): Promise<void> {
+  const srcFolderPath = path.join(databasePath, 'src');
+  const srcZipPath = srcFolderPath + '.zip';
+
+  if ((await fs.pathExists(srcFolderPath)) && !(await fs.pathExists(srcZipPath))) {
+    await zip(srcFolderPath, srcZipPath);
+    await fs.remove(srcFolderPath);
+  }
+}

extensions/ql-vscode/src/databases-ui.ts

@@ -1,13 +1,43 @@
 import * as path from 'path';
-import { DisposableObject } from 'semmle-vscode-utils';
-import { commands, Event, EventEmitter, ExtensionContext, ProviderResult, TreeDataProvider, TreeItem, Uri, window, env } from 'vscode';
-import * as cli from './cli';
-import { DatabaseItem, DatabaseManager, getUpgradesDirectories } from './databases';
-import { getOnDiskWorkspaceFolders, showAndLogErrorMessage } from './helpers';
+import { DisposableObject } from './pure/disposable-object';
+import {
+  Event,
+  EventEmitter,
+  ProviderResult,
+  TreeDataProvider,
+  TreeItem,
+  Uri,
+  window,
+  env,
+} from 'vscode';
+import * as fs from 'fs-extra';
+
+import {
+  DatabaseChangedEvent,
+  DatabaseItem,
+  DatabaseManager,
+} from './databases';
+import {
+  commandRunner,
+  commandRunnerWithProgress,
+  ProgressCallback,
+} from './commandRunner';
+import {
+  isLikelyDatabaseRoot,
+  isLikelyDbLanguageFolder,
+  showAndLogErrorMessage
+} from './helpers';
 import { logger } from './logging';
-import { clearCacheInDatabase, UserCancellationException } from './run-queries';
+import { clearCacheInDatabase } from './run-queries';
 import * as qsClient from './queryserver-client';
-import { upgradeDatabase } from './upgrades';
+import { upgradeDatabaseExplicit } from './upgrades';
+import {
+  importArchiveDatabase,
+  promptImportInternetDatabase,
+  promptImportLgtmDatabase,
+} from './databaseFetcher';
+import { CancellationToken } from 'vscode';
+import { asyncFilter } from './pure/helpers-pure';
 
 type ThemableIconPath = { light: string; dark: string } | string;
 
@@ -24,21 +54,23 @@ const SELECTED_DATABASE_ICON: ThemableIconPath = {
  */
 const INVALID_DATABASE_ICON: ThemableIconPath = 'media/red-x.svg';
 
-function joinThemableIconPath(base: string, iconPath: ThemableIconPath): ThemableIconPath {
+function joinThemableIconPath(
+  base: string,
+  iconPath: ThemableIconPath
+): ThemableIconPath {
   if (typeof iconPath == 'object')
     return {
       light: path.join(base, iconPath.light),
-      dark: path.join(base, iconPath.dark)
+      dark: path.join(base, iconPath.dark),
     };
-  else
-    return path.join(base, iconPath);
+  else return path.join(base, iconPath);
 }
 
 enum SortOrder {
   NameAsc = 'NameAsc',
   NameDesc = 'NameDesc',
   DateAddedAsc = 'DateAddedAsc',
-  DateAddedDesc = 'DateAddedDesc'
+  DateAddedDesc = 'DateAddedDesc',
 }
 
 /**
@@ -46,48 +78,71 @@ enum SortOrder {
  */
 class DatabaseTreeDataProvider extends DisposableObject
   implements TreeDataProvider<DatabaseItem> {
-
   private _sortOrder = SortOrder.NameAsc;
 
-  private readonly _onDidChangeTreeData = new EventEmitter<DatabaseItem | undefined>();
+  private readonly _onDidChangeTreeData = this.push(new EventEmitter<DatabaseItem | undefined>());
   private currentDatabaseItem: DatabaseItem | undefined;
 
-  constructor(private ctx: ExtensionContext, private databaseManager: DatabaseManager) {
+  constructor(
+    private databaseManager: DatabaseManager,
+    private readonly extensionPath: string
+  ) {
     super();
 
     this.currentDatabaseItem = databaseManager.currentDatabaseItem;
 
-    this.push(this.databaseManager.onDidChangeDatabaseItem(this.handleDidChangeDatabaseItem));
-    this.push(this.databaseManager.onDidChangeCurrentDatabaseItem(
-      this.handleDidChangeCurrentDatabaseItem));
+    this.push(
+      this.databaseManager.onDidChangeDatabaseItem(
+        this.handleDidChangeDatabaseItem
+      )
+    );
+    this.push(
+      this.databaseManager.onDidChangeCurrentDatabaseItem(
+        this.handleDidChangeCurrentDatabaseItem
+      )
+    );
   }
 
   public get onDidChangeTreeData(): Event<DatabaseItem | undefined> {
     return this._onDidChangeTreeData.event;
   }
 
-  private handleDidChangeDatabaseItem = (databaseItem: DatabaseItem | undefined): void => {
-    this._onDidChangeTreeData.fire(databaseItem);
-  }
+  private handleDidChangeDatabaseItem = (event: DatabaseChangedEvent): void => {
+    // Note that events from the database manager are instances of DatabaseChangedEvent
+    // and events fired by the UI are instances of DatabaseItem
 
-  private handleDidChangeCurrentDatabaseItem = (databaseItem: DatabaseItem | undefined): void => {
+    // When event.item is undefined, then the entire tree is refreshed.
+    // When event.item is a db item, then only that item is refreshed.
+    this._onDidChangeTreeData.fire(event.item);
+  };
+
+  private handleDidChangeCurrentDatabaseItem = (
+    event: DatabaseChangedEvent
+  ): void => {
     if (this.currentDatabaseItem) {
       this._onDidChangeTreeData.fire(this.currentDatabaseItem);
     }
-    this.currentDatabaseItem = databaseItem;
+    this.currentDatabaseItem = event.item;
     if (this.currentDatabaseItem) {
       this._onDidChangeTreeData.fire(this.currentDatabaseItem);
     }
-  }
+  };
 
   public getTreeItem(element: DatabaseItem): TreeItem {
     const item = new TreeItem(element.name);
     if (element === this.currentDatabaseItem) {
-      item.iconPath = joinThemableIconPath(this.ctx.extensionPath, SELECTED_DATABASE_ICON);
+      item.iconPath = joinThemableIconPath(
+        this.extensionPath,
+        SELECTED_DATABASE_ICON
+      );
     } else if (element.error !== undefined) {
-      item.iconPath = joinThemableIconPath(this.ctx.extensionPath, INVALID_DATABASE_ICON);
+      item.iconPath = joinThemableIconPath(
+        this.extensionPath,
+        INVALID_DATABASE_ICON
+      );
     }
     item.tooltip = element.databaseUri.fsPath;
+    item.description = element.language;
     return item;
   }
 
@@ -96,17 +151,16 @@ class DatabaseTreeDataProvider extends DisposableObject
       return this.databaseManager.databaseItems.slice(0).sort((db1, db2) => {
         switch (this.sortOrder) {
           case SortOrder.NameAsc:
-            return db1.name.localeCompare(db2.name);
+            return db1.name.localeCompare(db2.name, env.language);
           case SortOrder.NameDesc:
-            return db2.name.localeCompare(db1.name);
+            return db2.name.localeCompare(db1.name, env.language);
           case SortOrder.DateAddedAsc:
             return (db1.dateAdded || 0) - (db2.dateAdded || 0);
           case SortOrder.DateAddedDesc:
             return (db2.dateAdded || 0) - (db1.dateAdded || 0);
         }
       });
-    }
-    else {
+    } else {
       return [];
     }
   }
@@ -133,8 +187,7 @@ class DatabaseTreeDataProvider extends DisposableObject
 function getFirst(list: Uri[] | undefined): Uri | undefined {
   if (list === undefined || list.length === 0) {
     return undefined;
-  }
-  else {
+  } else {
     return list[0];
   }
 }
@@ -147,12 +200,13 @@ function getFirst(list: Uri[] | undefined): Uri | undefined {
  * XXX: no validation is done other than checking the directory name
  * to make sure it really is a database directory.
  */
-async function chooseDatabaseDir(): Promise<Uri | undefined> {
+async function chooseDatabaseDir(byFolder: boolean): Promise<Uri | undefined> {
   const chosen = await window.showOpenDialog({
-    openLabel: 'Choose Database',
-    canSelectFiles: true,
-    canSelectFolders: true,
-    canSelectMany: false
+    openLabel: byFolder ? 'Choose Database folder' : 'Choose Database archive',
+    canSelectFiles: !byFolder,
+    canSelectFolders: byFolder,
+    canSelectMany: false,
+    filters: byFolder ? {} : { Archives: ['zip'] },
   });
   return getFirst(chosen);
 }
@@ -161,35 +215,265 @@ export class DatabaseUI extends DisposableObject {
   private treeDataProvider: DatabaseTreeDataProvider;
 
   public constructor(
-    ctx: ExtensionContext,
-    private cliserver: cli.CodeQLCliServer,
     private databaseManager: DatabaseManager,
-    private readonly queryServer: qsClient.QueryServerClient | undefined
+    private readonly queryServer: qsClient.QueryServerClient | undefined,
+    private readonly storagePath: string,
+    readonly extensionPath: string
   ) {
     super();
 
-    this.treeDataProvider = this.push(new DatabaseTreeDataProvider(ctx, databaseManager));
-    this.push(window.createTreeView('codeQLDatabases', { treeDataProvider: this.treeDataProvider }));
-
-    ctx.subscriptions.push(commands.registerCommand('codeQL.chooseDatabase', this.handleChooseDatabase));
-    ctx.subscriptions.push(commands.registerCommand('codeQL.setCurrentDatabase', this.handleSetCurrentDatabase));
-    ctx.subscriptions.push(commands.registerCommand('codeQL.upgradeCurrentDatabase', this.handleUpgradeCurrentDatabase));
-    ctx.subscriptions.push(commands.registerCommand('codeQL.clearCache', this.handleClearCache));
-    ctx.subscriptions.push(commands.registerCommand('codeQLDatabases.setCurrentDatabase', this.handleMakeCurrentDatabase));
-    ctx.subscriptions.push(commands.registerCommand('codeQLDatabases.sortByName', this.handleSortByName));
-    ctx.subscriptions.push(commands.registerCommand('codeQLDatabases.sortByDateAdded', this.handleSortByDateAdded));
-    ctx.subscriptions.push(commands.registerCommand('codeQLDatabases.removeDatabase', this.handleRemoveDatabase));
-    ctx.subscriptions.push(commands.registerCommand('codeQLDatabases.upgradeDatabase', this.handleUpgradeDatabase));
-    ctx.subscriptions.push(commands.registerCommand('codeQLDatabases.renameDatabase', this.handleRenameDatabase));
-    ctx.subscriptions.push(commands.registerCommand('codeQLDatabases.openDatabaseFolder', this.handleOpenFolder));
+    this.treeDataProvider = this.push(
+      new DatabaseTreeDataProvider(databaseManager, extensionPath)
+    );
+    this.push(
+      window.createTreeView('codeQLDatabases', {
+        treeDataProvider: this.treeDataProvider,
+        canSelectMany: true,
+      })
+    );
   }
 
-  private handleMakeCurrentDatabase = async (databaseItem: DatabaseItem): Promise<void> => {
+  init() {
+    logger.log('Registering database panel commands.');
+    this.push(
+      commandRunnerWithProgress(
+        'codeQL.setCurrentDatabase',
+        this.handleSetCurrentDatabase,
+        {
+          title: 'Importing database from archive',
+        }
+      )
+    );
+    this.push(
+      commandRunnerWithProgress(
+        'codeQL.upgradeCurrentDatabase',
+        this.handleUpgradeCurrentDatabase,
+        {
+          title: 'Upgrading current database',
+          cancellable: true,
+        }
+      )
+    );
+    this.push(
+      commandRunnerWithProgress(
+        'codeQL.clearCache',
+        this.handleClearCache,
+        {
+          title: 'Clearing Cache',
+        })
+    );
+
+    this.push(
+      commandRunnerWithProgress(
+        'codeQLDatabases.chooseDatabaseFolder',
+        this.handleChooseDatabaseFolder,
+        {
+          title: 'Adding database from folder',
+        }
+      )
+    );
+    this.push(
+      commandRunnerWithProgress(
+        'codeQLDatabases.chooseDatabaseArchive',
+        this.handleChooseDatabaseArchive,
+        {
+          title: 'Adding database from archive',
+        }
+      )
+    );
+    this.push(
+      commandRunnerWithProgress(
+        'codeQLDatabases.chooseDatabaseInternet',
+        this.handleChooseDatabaseInternet,
+        {
+          title: 'Adding database from URL',
+        }
+      )
+    );
+    this.push(
+      commandRunnerWithProgress(
+        'codeQLDatabases.chooseDatabaseLgtm',
+        this.handleChooseDatabaseLgtm,
+        {
+          title: 'Adding database from LGTM. Choose a language from the dropdown, if requested.',
+        })
+    );
+    this.push(
+      commandRunner(
+        'codeQLDatabases.setCurrentDatabase',
+        this.handleMakeCurrentDatabase
+      )
+    );
+    this.push(
+      commandRunner(
+        'codeQLDatabases.sortByName',
+        this.handleSortByName
+      )
+    );
+    this.push(
+      commandRunner(
+        'codeQLDatabases.sortByDateAdded',
+        this.handleSortByDateAdded
+      )
+    );
+    this.push(
+      commandRunnerWithProgress(
+        'codeQLDatabases.removeDatabase',
+        this.handleRemoveDatabase,
+        {
+          title: 'Removing database',
+          cancellable: false
+        }
+      )
+    );
+    this.push(
+      commandRunnerWithProgress(
+        'codeQLDatabases.upgradeDatabase',
+        this.handleUpgradeDatabase,
+        {
+          title: 'Upgrading database',
+          cancellable: true,
+        }
+      )
+    );
+    this.push(
+      commandRunner(
+        'codeQLDatabases.renameDatabase',
+        this.handleRenameDatabase
+      )
+    );
+    this.push(
+      commandRunner(
+        'codeQLDatabases.openDatabaseFolder',
+        this.handleOpenFolder
+      )
+    );
+    this.push(
+      commandRunner(
+        'codeQLDatabases.removeOrphanedDatabases',
+        this.handleRemoveOrphanedDatabases
+      )
+    );
+  }
+
+  private handleMakeCurrentDatabase = async (
+    databaseItem: DatabaseItem
+  ): Promise<void> => {
     await this.databaseManager.setCurrentDatabaseItem(databaseItem);
-  }
+  };
 
-  private handleChooseDatabase = async (): Promise<DatabaseItem | undefined> => {
-    return await this.chooseAndSetDatabase();
+  handleChooseDatabaseFolder = async (
+    progress: ProgressCallback,
+    token: CancellationToken
+  ): Promise<DatabaseItem | undefined> => {
+    try {
+      return await this.chooseAndSetDatabase(true, progress, token);
+    } catch (e) {
+      showAndLogErrorMessage(e.message);
+      return undefined;
+    }
+  };
+
+  handleRemoveOrphanedDatabases = async (): Promise<void> => {
+    logger.log('Removing orphaned databases from workspace storage.');
+    let dbDirs = undefined;
+
+    if (
+      !(await fs.pathExists(this.storagePath)) ||
+      !(await fs.stat(this.storagePath)).isDirectory()
+    ) {
+      logger.log('Missing or invalid storage directory. Not trying to remove orphaned databases.');
+      return;
+    }
+
+    dbDirs =
+      // read directory
+      (await fs.readdir(this.storagePath, { withFileTypes: true }))
+        // remove non-directories
+        .filter(dirent => dirent.isDirectory())
+        // get the full path
+        .map(dirent => path.join(this.storagePath, dirent.name))
+        // remove databases still in workspace
+        .filter(dbDir => {
+          const dbUri = Uri.file(dbDir);
+          return this.databaseManager.databaseItems.every(item => item.databaseUri.fsPath !== dbUri.fsPath);
+        });
+
+    // remove non-databases
+    dbDirs = await asyncFilter(dbDirs, isLikelyDatabaseRoot);
+
+    if (!dbDirs.length) {
+      logger.log('No orphaned databases found.');
+      return;
+    }
+
+    // delete
+    const failures = [] as string[];
+    await Promise.all(
+      dbDirs.map(async dbDir => {
+        try {
+          logger.log(`Deleting orphaned database '${dbDir}'.`);
+          await fs.rmdir(dbDir, { recursive: true } as any);  // typings doesn't recognize the options argument
+        } catch (e) {
+          failures.push(`${path.basename(dbDir)}`);
+        }
+      })
+    );
+
+    if (failures.length) {
+      const dirname = path.dirname(failures[0]);
+      showAndLogErrorMessage(
+        `Failed to delete unused databases (${
+        failures.join(', ')
+        }).\nTo delete unused databases, please remove them manually from the storage folder ${dirname}.`
+      );
+    }
+  };
+
+
+  handleChooseDatabaseArchive = async (
+    progress: ProgressCallback,
+    token: CancellationToken
+  ): Promise<DatabaseItem | undefined> => {
+    try {
+      return await this.chooseAndSetDatabase(false, progress, token);
+    } catch (e) {
+      showAndLogErrorMessage(e.message);
+      return undefined;
+    }
+  };
+
+  handleChooseDatabaseInternet = async (
+    progress: ProgressCallback,
+    token: CancellationToken
+  ): Promise<
+    DatabaseItem | undefined
+  > => {
+    return await promptImportInternetDatabase(
+      this.databaseManager,
+      this.storagePath,
+      progress,
+      token
+    );
+  };
+
+  handleChooseDatabaseLgtm = async (
+    progress: ProgressCallback,
+    token: CancellationToken
+  ): Promise<DatabaseItem | undefined> => {
+    return await promptImportLgtmDatabase(
+      this.databaseManager,
+      this.storagePath,
+      progress,
+      token
+    );
+  };
+
+  async tryUpgradeCurrentDatabase(
+    progress: ProgressCallback,
+    token: CancellationToken
+  ) {
+    await this.handleUpgradeCurrentDatabase(progress, token);
   }
 
   private handleSortByName = async () => {
@@ -198,7 +482,7 @@ export class DatabaseUI extends DisposableObject {
     } else {
       this.treeDataProvider.sortOrder = SortOrder.NameAsc;
     }
-  }
+  };
 
   private handleSortByDateAdded = async () => {
     if (this.treeDataProvider.sortOrder === SortOrder.DateAddedAsc) {
@@ -206,114 +490,174 @@ export class DatabaseUI extends DisposableObject {
     } else {
       this.treeDataProvider.sortOrder = SortOrder.DateAddedAsc;
     }
-  }
+  };
 
-  private handleUpgradeCurrentDatabase = async (): Promise<void> => {
-    await this.handleUpgradeDatabase(this.databaseManager.currentDatabaseItem);
-  }
+  private handleUpgradeCurrentDatabase = async (
+    progress: ProgressCallback,
+    token: CancellationToken,
+  ): Promise<void> => {
+    await this.handleUpgradeDatabase(
+      progress, token,
+      this.databaseManager.currentDatabaseItem,
+      []
+    );
+  };
 
-  private handleUpgradeDatabase = async (databaseItem: DatabaseItem | undefined): Promise<void> => {
+  private handleUpgradeDatabase = async (
+    progress: ProgressCallback,
+    token: CancellationToken,
+    databaseItem: DatabaseItem | undefined,
+    multiSelect: DatabaseItem[] | undefined,
+  ): Promise<void> => {
+    if (multiSelect?.length) {
+      await Promise.all(
+        multiSelect.map((dbItem) => this.handleUpgradeDatabase(progress, token, dbItem, []))
+      );
+    }
     if (this.queryServer === undefined) {
-      logger.log('Received request to upgrade database, but there is no running query server.');
-      return;
+      throw new Error(
+        'Received request to upgrade database, but there is no running query server.'
+      );
     }
     if (databaseItem === undefined) {
-      logger.log('Received request to upgrade database, but no database was provided.');
-      return;
+      throw new Error(
+        'Received request to upgrade database, but no database was provided.'
+      );
     }
     if (databaseItem.contents === undefined) {
-      logger.log('Received request to upgrade database, but database contents could not be found.');
-      return;
+      throw new Error(
+        'Received request to upgrade database, but database contents could not be found.'
+      );
     }
     if (databaseItem.contents.dbSchemeUri === undefined) {
-      logger.log('Received request to upgrade database, but database has no schema.');
-      return;
+      throw new Error(
+        'Received request to upgrade database, but database has no schema.'
+      );
     }
 
     // Search for upgrade scripts in any workspace folders available
-    const searchPath: string[] = getOnDiskWorkspaceFolders();
 
-    const upgradeInfo = await this.cliserver.resolveUpgrades(
-      databaseItem.contents.dbSchemeUri.fsPath,
-      searchPath,
+    await upgradeDatabaseExplicit(
+      this.queryServer,
+      databaseItem,
+      progress,
+      token
     );
+  };
 
-    const { scripts, finalDbscheme } = upgradeInfo;
-
-    if (finalDbscheme === undefined) {
-      logger.log('Could not determine target dbscheme to upgrade to.');
-      return;
+  private handleClearCache = async (
+    progress: ProgressCallback,
+    token: CancellationToken,
+  ): Promise<void> => {
+    if (
+      this.queryServer !== undefined &&
+      this.databaseManager.currentDatabaseItem !== undefined
+    ) {
+      await clearCacheInDatabase(
+        this.queryServer,
+        this.databaseManager.currentDatabaseItem,
+        progress,
+        token
+      );
     }
-    const targetDbSchemeUri = Uri.file(finalDbscheme);
+  };
 
+  private handleSetCurrentDatabase = async (
+    progress: ProgressCallback,
+    token: CancellationToken,
+    uri: Uri,
+  ): Promise<void> => {
     try {
-      await upgradeDatabase(this.queryServer, databaseItem, targetDbSchemeUri, getUpgradesDirectories(scripts));
-    }
-    catch (e) {
-      if (e instanceof UserCancellationException) {
-        logger.log(e.message);
-      }
-      else
-        throw e;
-    }
-  }
-
-  private handleClearCache = async (): Promise<void> => {
-    if ((this.queryServer !== undefined) &&
-      (this.databaseManager.currentDatabaseItem !== undefined)) {
-
-      await clearCacheInDatabase(this.queryServer, this.databaseManager.currentDatabaseItem);
-    }
-  }
-
-  private handleSetCurrentDatabase = async (uri: Uri): Promise<DatabaseItem | undefined> => {
-    return await this.setCurrentDatabase(uri);
-  }
-
-  private handleRemoveDatabase = (databaseItem: DatabaseItem): void => {
-    this.databaseManager.removeDatabaseItem(databaseItem);
-  }
-
-  private handleRenameDatabase = async (databaseItem: DatabaseItem): Promise<void> => {
-    try {
-      const newName = await window.showInputBox({
-        prompt: 'Choose new database name',
-        value: databaseItem.name
-      });
-
-      if (newName) {
-        this.databaseManager.renameDatabaseItem(databaseItem, newName);
+      // Assume user has selected an archive if the file has a .zip extension
+      if (uri.path.endsWith('.zip')) {
+        await importArchiveDatabase(
+          uri.toString(true),
+          this.databaseManager,
+          this.storagePath,
+          progress,
+          token
+        );
+      } else {
+        await this.setCurrentDatabase(progress, token, uri);
       }
     } catch (e) {
-      showAndLogErrorMessage(e.message);
+      // rethrow and let this be handled by default error handling.
+      throw new Error(
+        `Could not set database to ${path.basename(uri.fsPath)}. Reason: ${
+        e.message
+        }`
+      );
     }
-  }
+  };
 
-  private handleOpenFolder = async (databaseItem: DatabaseItem): Promise<void> => {
-    try {
+  private handleRemoveDatabase = async (
+    progress: ProgressCallback,
+    token: CancellationToken,
+    databaseItem: DatabaseItem,
+    multiSelect: DatabaseItem[] | undefined
+  ): Promise<void> => {
+    if (multiSelect?.length) {
+      await Promise.all(multiSelect.map((dbItem) =>
+        this.databaseManager.removeDatabaseItem(progress, token, dbItem)
+      ));
+    } else {
+      await this.databaseManager.removeDatabaseItem(progress, token, databaseItem);
+    }
+  };
+
+  private handleRenameDatabase = async (
+    databaseItem: DatabaseItem,
+    multiSelect: DatabaseItem[] | undefined
+  ): Promise<void> => {
+    this.assertSingleDatabase(multiSelect);
+
+    const newName = await window.showInputBox({
+      prompt: 'Choose new database name',
+      value: databaseItem.name,
+    });
+
+    if (newName) {
+      this.databaseManager.renameDatabaseItem(databaseItem, newName);
+    }
+  };
+
+  private handleOpenFolder = async (
+    databaseItem: DatabaseItem,
+    multiSelect: DatabaseItem[] | undefined
+  ): Promise<void> => {
+    if (multiSelect?.length) {
+      await Promise.all(
+        multiSelect.map((dbItem) => env.openExternal(dbItem.databaseUri))
+      );
+    } else {
       await env.openExternal(databaseItem.databaseUri);
-    } catch (e) {
-      showAndLogErrorMessage(e.message);
     }
-  }
+  };
 
   /**
    * Return the current database directory. If we don't already have a
    * current database, ask the user for one, and return that, or
    * undefined if they cancel.
    */
-  public async getDatabaseItem(): Promise<DatabaseItem | undefined> {
+  public async getDatabaseItem(
+    progress: ProgressCallback,
+    token: CancellationToken
+  ): Promise<DatabaseItem | undefined> {
     if (this.databaseManager.currentDatabaseItem === undefined) {
-      await this.chooseAndSetDatabase();
+      await this.chooseAndSetDatabase(false, progress, token);
     }
 
     return this.databaseManager.currentDatabaseItem;
   }
 
-  private async setCurrentDatabase(uri: Uri): Promise<DatabaseItem | undefined> {
+  private async setCurrentDatabase(
+    progress: ProgressCallback,
+    token: CancellationToken,
+    uri: Uri
+  ): Promise<DatabaseItem | undefined> {
     let databaseItem = this.databaseManager.findDatabaseItem(uri);
     if (databaseItem === undefined) {
-      databaseItem = await this.databaseManager.openDatabase(uri);
+      databaseItem = await this.databaseManager.openDatabase(progress, token, uri);
     }
     await this.databaseManager.setCurrentDatabaseItem(databaseItem);
 
@@ -324,13 +668,63 @@ export class DatabaseUI extends DisposableObject {
    * Ask the user for a database directory. Returns the chosen database, or `undefined` if the
    * operation was canceled.
    */
-  private async chooseAndSetDatabase(): Promise<DatabaseItem | undefined> {
-    const uri = await chooseDatabaseDir();
-    if (uri !== undefined) {
-      return await this.setCurrentDatabase(uri);
-    }
-    else {
+  private async chooseAndSetDatabase(
+    byFolder: boolean,
+    progress: ProgressCallback,
+    token: CancellationToken,
+  ): Promise<DatabaseItem | undefined> {
+    const uri = await chooseDatabaseDir(byFolder);
+
+    if (!uri) {
       return undefined;
     }
+
+    if (byFolder) {
+      const fixedUri = await this.fixDbUri(uri);
+      // we are selecting a database folder
+      return await this.setCurrentDatabase(progress, token, fixedUri);
+    } else {
+      // we are selecting a database archive. Must unzip into a workspace-controlled area
+      // before importing.
+      return await importArchiveDatabase(
+        uri.toString(true),
+        this.databaseManager,
+        this.storagePath,
+        progress,
+        token
+      );
+    }
+  }
+
+  /**
+   * Perform some heuristics to ensure a proper database location is chosen.
+   *
+   * 1. If the selected URI to add is a file, choose the containing directory
+   * 2. If the selected URI is a directory matching db-*, choose the containing directory
+   * 3. choose the current directory
+   *
+   * @param uri a URI that is a database folder or inside it
+   *
+   * @return the actual database folder found by using the heuristics above.
+   */
+  private async fixDbUri(uri: Uri): Promise<Uri> {
+    let dbPath = uri.fsPath;
+    if ((await fs.stat(dbPath)).isFile()) {
+      dbPath = path.dirname(dbPath);
+    }
+
+    if (isLikelyDbLanguageFolder(dbPath)) {
+      dbPath = path.dirname(dbPath);
+    }
+    return Uri.file(dbPath);
+  }
+
+  private assertSingleDatabase(
+    multiSelect: DatabaseItem[] = [],
+    message = 'Please select a single database.'
+  ) {
+    if (multiSelect.length > 1) {
+      throw new Error(message);
+    }
   }
 }

extensions/ql-vscode/src/databases.ts

@@ -4,11 +4,21 @@ import * as path from 'path';
 import * as vscode from 'vscode';
 import * as cli from './cli';
 import { ExtensionContext } from 'vscode';
-import { showAndLogErrorMessage, showAndLogWarningMessage, showAndLogInformationMessage } from './helpers';
-import { zipArchiveScheme, encodeSourceArchiveUri, decodeSourceArchiveUri } from './archive-filesystem-provider';
-import { DisposableObject } from 'semmle-vscode-utils';
-import { QueryServerConfig } from './config';
+import {
+  showAndLogErrorMessage,
+  showAndLogWarningMessage,
+  showAndLogInformationMessage,
+  isLikelyDatabaseRoot
+} from './helpers';
+import {
+  ProgressCallback,
+  withProgress
+} from './commandRunner';
+import { zipArchiveScheme, encodeArchiveBasePath, decodeSourceArchiveUri, encodeSourceArchiveUri } from './archive-filesystem-provider';
+import { DisposableObject } from './pure/disposable-object';
 import { Logger, logger } from './logging';
+import { registerDatabases, Dataset, deregisterDatabases } from './pure/messages';
+import { QueryServerClient } from './queryserver-client';
 
 /**
  * databases.ts
@@ -36,11 +46,13 @@ export interface DatabaseOptions {
   displayName?: string;
   ignoreSourceArchive?: boolean;
   dateAdded?: number | undefined;
+  language?: string;
 }
 
-interface FullDatabaseOptions extends DatabaseOptions {
+export interface FullDatabaseOptions extends DatabaseOptions {
   ignoreSourceArchive: boolean;
   dateAdded: number | undefined;
+  language: string | undefined;
 }
 
 interface PersistedDatabaseItem {
@@ -113,7 +125,7 @@ async function findSourceArchive(
   databasePath: string, silent = false
 ): Promise<vscode.Uri | undefined> {
 
-  const relativePaths = ['src', 'output/src_archive']
+  const relativePaths = ['src', 'output/src_archive'];
 
   for (const relativePath of relativePaths) {
     const basePath = path.join(databasePath, relativePath);
@@ -121,19 +133,21 @@ async function findSourceArchive(
 
     if (await fs.pathExists(basePath)) {
       return vscode.Uri.file(basePath);
-    }
-    else if (await fs.pathExists(zipPath)) {
-      return vscode.Uri.file(zipPath).with({ scheme: zipArchiveScheme });
+    } else if (await fs.pathExists(zipPath)) {
+      return encodeArchiveBasePath(zipPath);
     }
   }
-  if (!silent)
-    showAndLogInformationMessage(`Could not find source archive for database '${databasePath}'. Assuming paths are absolute.`);
+  if (!silent) {
+    showAndLogInformationMessage(
+      `Could not find source archive for database '${databasePath}'. Assuming paths are absolute.`
+    );
+  }
   return undefined;
 }
 
 async function resolveDatabase(
   databasePath: string
-): Promise<DatabaseContents | undefined> {
+): Promise<DatabaseContents> {
 
   const name = path.basename(databasePath);
 
@@ -155,20 +169,6 @@ async function getDbSchemeFiles(dbDirectory: string): Promise<string[]> {
   return await glob('*.dbscheme', { cwd: dbDirectory });
 }
 
-async function resolveRawDataset(datasetPath: string): Promise<DatabaseContents | undefined> {
-  if ((await getDbSchemeFiles(datasetPath)).length > 0) {
-    return {
-      kind: DatabaseKind.RawDataset,
-      name: path.basename(datasetPath),
-      datasetUri: vscode.Uri.file(datasetPath),
-      sourceArchiveUri: undefined
-    };
-  }
-  else {
-    return undefined;
-  }
-}
-
 async function resolveDatabaseContents(uri: vscode.Uri): Promise<DatabaseContents> {
   if (uri.scheme !== 'file') {
     throw new Error(`Database URI scheme '${uri.scheme}' not supported; only 'file' URIs are supported.`);
@@ -178,7 +178,7 @@ async function resolveDatabaseContents(uri: vscode.Uri): Promise<DatabaseContent
     throw new InvalidDatabaseError(`Database '${databasePath}' does not exist.`);
   }
 
-  const contents = await resolveDatabase(databasePath) || await resolveRawDataset(databasePath);
+  const contents = await resolveDatabase(databasePath);
 
   if (contents === undefined) {
     throw new InvalidDatabaseError(`'${databasePath}' is not a valid database.`);
@@ -205,6 +205,9 @@ export interface DatabaseItem {
   readonly databaseUri: vscode.Uri;
   /** The name of the database to be displayed in the UI */
   name: string;
+
+  /** The primary language of the database or empty string if unknown */
+  readonly language: string;
   /** The URI of the database's source archive, or `undefined` if no source archive is to be used. */
   readonly sourceArchive: vscode.Uri | undefined;
   /**
@@ -261,18 +264,44 @@ export interface DatabaseItem {
    * Holds if `uri` belongs to this database's source archive.
    */
   belongsToSourceArchiveExplorerUri(uri: vscode.Uri): boolean;
+
+  /**
+   * Gets the state of this database, to be persisted in the workspace state.
+   */
+  getPersistedState(): PersistedDatabaseItem;
 }
 
-class DatabaseItemImpl implements DatabaseItem {
+export enum DatabaseEventKind {
+  Add = 'Add',
+  Remove = 'Remove',
+
+  // Fired when databases are refreshed from persisted state
+  Refresh = 'Refresh',
+
+  // Fired when the current database changes
+  Change = 'Change',
+
+  Rename = 'Rename'
+}
+
+export interface DatabaseChangedEvent {
+  kind: DatabaseEventKind;
+  item: DatabaseItem | undefined;
+}
+
+// Exported for testing
+export class DatabaseItemImpl implements DatabaseItem {
   private _error: Error | undefined = undefined;
   private _contents: DatabaseContents | undefined;
   /** A cache of database info */
   private _dbinfo: cli.DbInfo | undefined;
 
-  public constructor(public readonly databaseUri: vscode.Uri,
-    contents: DatabaseContents | undefined, private options: FullDatabaseOptions,
-    private readonly onChanged: (item: DatabaseItemImpl) => void) {
-
+  public constructor(
+    public readonly databaseUri: vscode.Uri,
+    contents: DatabaseContents | undefined,
+    private options: FullDatabaseOptions,
+    private readonly onChanged: (event: DatabaseChangedEvent) => void
+  ) {
     this._contents = contents;
   }
 
@@ -295,8 +324,7 @@ class DatabaseItemImpl implements DatabaseItem {
   public get sourceArchive(): vscode.Uri | undefined {
     if (this.options.ignoreSourceArchive || (this._contents === undefined)) {
       return undefined;
-    }
-    else {
+    } else {
       return this._contents.sourceArchiveUri;
     }
   }
@@ -326,46 +354,52 @@ class DatabaseItemImpl implements DatabaseItem {
       }
     }
     finally {
-      this.onChanged(this);
+      this.onChanged({
+        kind: DatabaseEventKind.Refresh,
+        item: this
+      });
     }
   }
 
-  public resolveSourceFile(file: string | undefined): vscode.Uri {
+  public resolveSourceFile(uriStr: string | undefined): vscode.Uri {
     const sourceArchive = this.sourceArchive;
-    if (sourceArchive === undefined) {
-      if (file !== undefined) {
-        // Treat it as an absolute path.
-        return vscode.Uri.file(file);
-      }
-      else {
+    const uri = uriStr ? vscode.Uri.parse(uriStr, true) : undefined;
+    if (uri && uri.scheme !== 'file') {
+      throw new Error(`Invalid uri scheme in ${uriStr}. Only 'file' is allowed.`);
+    }
+    if (!sourceArchive) {
+      if (uri) {
+        return uri;
+      } else {
         return this.databaseUri;
       }
     }
-    else {
-      if (file !== undefined) {
-        const absoluteFilePath = file.replace(':', '_');
-        // Strip any leading slashes from the file path, and replace `:` with `_`.
-        const relativeFilePath = absoluteFilePath.replace(/^\/*/, '').replace(':', '_');
-        if (sourceArchive.scheme == zipArchiveScheme) {
-          return encodeSourceArchiveUri({
-            pathWithinSourceArchive: absoluteFilePath,
-            sourceArchiveZipPath: sourceArchive.fsPath,
-          });
-        }
-        else {
-          let newPath = sourceArchive.path;
-          if (!newPath.endsWith('/')) {
-            // Ensure a trailing slash.
-            newPath += '/';
-          }
-          newPath += relativeFilePath;
 
-          return sourceArchive.with({ path: newPath });
+    if (uri) {
+      const relativeFilePath = decodeURI(uri.path).replace(':', '_').replace(/^\/*/, '');
+      if (sourceArchive.scheme === zipArchiveScheme) {
+        const zipRef = decodeSourceArchiveUri(sourceArchive);
+        const pathWithinSourceArchive = zipRef.pathWithinSourceArchive === '/'
+          ? relativeFilePath
+          : zipRef.pathWithinSourceArchive + '/' + relativeFilePath;
+        return encodeSourceArchiveUri({
+          pathWithinSourceArchive,
+          sourceArchiveZipPath: zipRef.sourceArchiveZipPath,
+        });
+
+      } else {
+        let newPath = sourceArchive.path;
+        if (!newPath.endsWith('/')) {
+          // Ensure a trailing slash.
+          newPath += '/';
         }
+        newPath += relativeFilePath;
+
+        return sourceArchive.with({ path: newPath });
       }
-      else {
-        return sourceArchive;
-      }
+
+    } else {
+      return sourceArchive;
     }
   }
 
@@ -383,10 +417,7 @@ class DatabaseItemImpl implements DatabaseItem {
    * Holds if the database item refers to an exported snapshot
    */
   public async hasMetadataFile(): Promise<boolean> {
-    return (await Promise.all([
-      fs.pathExists(path.join(this.databaseUri.fsPath, '.dbinfo')),
-      fs.pathExists(path.join(this.databaseUri.fsPath, 'codeql-database.yml'))
-    ])).some(x => x);
+    return await isLikelyDatabaseRoot(this.databaseUri.fsPath);
   }
 
   /**
@@ -416,6 +447,10 @@ class DatabaseItemImpl implements DatabaseItem {
     return dbInfo.datasetFolder;
   }
 
+  public get language() {
+    return this.options.language || '';
+  }
+
   /**
    * Returns the root uri of the virtual filesystem for this database's source archive.
    */
@@ -423,10 +458,7 @@ class DatabaseItemImpl implements DatabaseItem {
     const sourceArchive = this.sourceArchive;
     if (sourceArchive === undefined || !sourceArchive.fsPath.endsWith('.zip'))
       return undefined;
-    return encodeSourceArchiveUri({
-      pathWithinSourceArchive: '/',
-      sourceArchiveZipPath: sourceArchive.fsPath,
-    });
+    return encodeArchiveBasePath(sourceArchive.fsPath);
   }
 
   /**
@@ -464,47 +496,71 @@ function eventFired<T>(event: vscode.Event<T>, timeoutMs = 1000): Promise<T | un
 }
 
 export class DatabaseManager extends DisposableObject {
-  private readonly _onDidChangeDatabaseItem = this.push(new vscode.EventEmitter<DatabaseItem | undefined>());
+  private readonly _onDidChangeDatabaseItem = this.push(new vscode.EventEmitter<DatabaseChangedEvent>());
 
   readonly onDidChangeDatabaseItem = this._onDidChangeDatabaseItem.event;
 
-  private readonly _onDidChangeCurrentDatabaseItem = this.push(new vscode.EventEmitter<DatabaseItem | undefined>());
+  private readonly _onDidChangeCurrentDatabaseItem = this.push(new vscode.EventEmitter<DatabaseChangedEvent>());
   readonly onDidChangeCurrentDatabaseItem = this._onDidChangeCurrentDatabaseItem.event;
 
-  private readonly _databaseItems: DatabaseItemImpl[] = [];
+  private readonly _databaseItems: DatabaseItem[] = [];
   private _currentDatabaseItem: DatabaseItem | undefined = undefined;
 
-  constructor(private ctx: ExtensionContext,
-    public config: QueryServerConfig,
-    public logger: Logger) {
+  constructor(
+    private readonly ctx: ExtensionContext,
+    private readonly qs: QueryServerClient,
+    private readonly cli: cli.CodeQLCliServer,
+    public logger: Logger
+  ) {
     super();
 
-    this.loadPersistedState();  // Let this run async.
+    qs.onDidStartQueryServer(this.reregisterDatabases.bind(this));
+
+    // Let this run async.
+    this.loadPersistedState();
   }
 
   public async openDatabase(
-    uri: vscode.Uri, options?: DatabaseOptions
+    progress: ProgressCallback,
+    token: vscode.CancellationToken,
+    uri: vscode.Uri,
   ): Promise<DatabaseItem> {
-
     const contents = await resolveDatabaseContents(uri);
-    const realOptions = options || {};
     // Ignore the source archive for QLTest databases by default.
     const isQLTestDatabase = path.extname(uri.fsPath) === '.testproj';
     const fullOptions: FullDatabaseOptions = {
-      ignoreSourceArchive: (realOptions.ignoreSourceArchive !== undefined) ?
-        realOptions.ignoreSourceArchive : isQLTestDatabase,
-      displayName: realOptions.displayName,
-      dateAdded: realOptions.dateAdded || Date.now()
+      ignoreSourceArchive: isQLTestDatabase,
+      // displayName is only set if a user explicitly renames a database
+      displayName: undefined,
+      dateAdded: Date.now(),
+      language: await this.getPrimaryLanguage(uri.fsPath)
     };
-    const databaseItem = new DatabaseItemImpl(uri, contents, fullOptions, (item) => {
-      this._onDidChangeDatabaseItem.fire(item);
+    const databaseItem = new DatabaseItemImpl(uri, contents, fullOptions, (event) => {
+      this._onDidChangeDatabaseItem.fire(event);
     });
-    await this.addDatabaseItem(databaseItem);
+
+    await this.addDatabaseItem(progress, token, databaseItem);
     await this.addDatabaseSourceArchiveFolder(databaseItem);
 
     return databaseItem;
   }
 
+  private async reregisterDatabases(
+    progress: ProgressCallback,
+    token: vscode.CancellationToken
+  ) {
+    let completed = 0;
+    await Promise.all(this._databaseItems.map(async (databaseItem) => {
+      await this.registerDatabase(progress, token, databaseItem);
+      completed++;
+      progress({
+        maxStep: this._databaseItems.length,
+        step: completed,
+        message: 'Re-registering databases'
+      });
+    }));
+  }
+
   private async addDatabaseSourceArchiveFolder(item: DatabaseItem) {
     // The folder may already be in workspace state from a previous
     // session. If not, add it.
@@ -545,12 +601,15 @@ export class DatabaseManager extends DisposableObject {
   }
 
   private async createDatabaseItemFromPersistedState(
+    progress: ProgressCallback,
+    token: vscode.CancellationToken,
     state: PersistedDatabaseItem
   ): Promise<DatabaseItem> {
 
     let displayName: string | undefined = undefined;
     let ignoreSourceArchive = false;
     let dateAdded = undefined;
+    let language = undefined;
     if (state.options) {
       if (typeof state.options.displayName === 'string') {
         displayName = state.options.displayName;
@@ -561,43 +620,69 @@ export class DatabaseManager extends DisposableObject {
       if (typeof state.options.dateAdded === 'number') {
         dateAdded = state.options.dateAdded;
       }
+      language = state.options.language;
     }
+
+    const dbBaseUri = vscode.Uri.parse(state.uri, true);
+    if (language === undefined) {
+      // we haven't been successful yet at getting the language. try again
+      language = await this.getPrimaryLanguage(dbBaseUri.fsPath);
+    }
+
     const fullOptions: FullDatabaseOptions = {
       ignoreSourceArchive,
       displayName,
-      dateAdded
+      dateAdded,
+      language
     };
-    const item = new DatabaseItemImpl(vscode.Uri.parse(state.uri), undefined, fullOptions,
-      (item) => {
-        this._onDidChangeDatabaseItem.fire(item)
+    const item = new DatabaseItemImpl(dbBaseUri, undefined, fullOptions,
+      (event) => {
+        this._onDidChangeDatabaseItem.fire(event);
       });
-    await this.addDatabaseItem(item);
 
+    await this.addDatabaseItem(progress, token, item);
     return item;
   }
 
   private async loadPersistedState(): Promise<void> {
-    const currentDatabaseUri = this.ctx.workspaceState.get<string>(CURRENT_DB);
-    const databases = this.ctx.workspaceState.get<PersistedDatabaseItem[]>(DB_LIST, []);
-
-    try {
-      for (const database of databases) {
-        const databaseItem = await this.createDatabaseItemFromPersistedState(database);
+    return withProgress({
+      location: vscode.ProgressLocation.Notification
+    },
+      async (progress, token) => {
+        const currentDatabaseUri = this.ctx.workspaceState.get<string>(CURRENT_DB);
+        const databases = this.ctx.workspaceState.get<PersistedDatabaseItem[]>(DB_LIST, []);
+        let step = 0;
+        progress({
+          maxStep: databases.length,
+          message: 'Loading persisted databases',
+          step
+        });
         try {
-          await databaseItem.refresh();
-          if (currentDatabaseUri === database.uri) {
-            this.setCurrentDatabaseItem(databaseItem, true);
+          for (const database of databases) {
+            progress({
+              maxStep: databases.length,
+              message: `Loading ${database.options?.displayName || 'databases'}`,
+              step: ++step
+            });
+
+            const databaseItem = await this.createDatabaseItemFromPersistedState(progress, token, database);
+            try {
+              await databaseItem.refresh();
+              await this.registerDatabase(progress, token, databaseItem);
+              if (currentDatabaseUri === database.uri) {
+                this.setCurrentDatabaseItem(databaseItem, true);
+              }
+            }
+            catch (e) {
+              // When loading from persisted state, leave invalid databases in the list. They will be
+              // marked as invalid, and cannot be set as the current database.
+            }
           }
+        } catch (e) {
+          // database list had an unexpected type - nothing to be done?
+          showAndLogErrorMessage(`Database list loading failed: ${e.message}`);
         }
-        catch (e) {
-          // When loading from persisted state, leave invalid databases in the list. They will be
-          // marked as invalid, and cannot be set as the current database.
-        }
-      }
-    } catch (e) {
-      // database list had an unexpected type - nothing to be done?
-      showAndLogErrorMessage(`Database list loading failed: ${e.message}`);
-    }
+      });
   }
 
   public get databaseItems(): readonly DatabaseItem[] {
@@ -608,8 +693,10 @@ export class DatabaseManager extends DisposableObject {
     return this._currentDatabaseItem;
   }
 
-  public async setCurrentDatabaseItem(item: DatabaseItem | undefined,
-    skipRefresh = false): Promise<void> {
+  public async setCurrentDatabaseItem(
+    item: DatabaseItem | undefined,
+    skipRefresh = false
+  ): Promise<void> {
 
     if (!skipRefresh && (item !== undefined)) {
       await item.refresh();  // Will throw on invalid database.
@@ -617,7 +704,11 @@ export class DatabaseManager extends DisposableObject {
     if (this._currentDatabaseItem !== item) {
       this._currentDatabaseItem = item;
       this.updatePersistedCurrentDatabaseItem();
-      this._onDidChangeCurrentDatabaseItem.fire(item);
+
+      this._onDidChangeCurrentDatabaseItem.fire({
+        item,
+        kind: DatabaseEventKind.Change
+      });
     }
   }
 
@@ -640,21 +731,45 @@ export class DatabaseManager extends DisposableObject {
     return this._databaseItems.find(item => item.sourceArchive && item.sourceArchive.toString(true) === uriString);
   }
 
-  private async addDatabaseItem(item: DatabaseItemImpl) {
+  private async addDatabaseItem(
+    progress: ProgressCallback,
+    token: vscode.CancellationToken,
+    item: DatabaseItem
+  ) {
     this._databaseItems.push(item);
     this.updatePersistedDatabaseList();
-    this._onDidChangeDatabaseItem.fire(undefined);
+
+    // Add this database item to the allow-list
+    // Database items reconstituted from persisted state
+    // will not have their contents yet.
+    if (item.contents?.datasetUri) {
+      await this.registerDatabase(progress, token, item);
+    }
+    // note that we use undefined as the item in order to reset the entire tree
+    this._onDidChangeDatabaseItem.fire({
+      item: undefined,
+      kind: DatabaseEventKind.Add
+    });
   }
 
   public async renameDatabaseItem(item: DatabaseItem, newName: string) {
     item.name = newName;
     this.updatePersistedDatabaseList();
-    this._onDidChangeDatabaseItem.fire(item);
+    this._onDidChangeDatabaseItem.fire({
+      // pass undefined so that the entire tree is rebuilt in order to re-sort
+      item: undefined,
+      kind: DatabaseEventKind.Rename
+    });
   }
 
-  public removeDatabaseItem(item: DatabaseItem) {
-    if (this._currentDatabaseItem == item)
+  public async removeDatabaseItem(
+    progress: ProgressCallback,
+    token: vscode.CancellationToken,
+    item: DatabaseItem
+  ) {
+    if (this._currentDatabaseItem == item) {
       this._currentDatabaseItem = undefined;
+    }
     const index = this.databaseItems.findIndex(searchItem => searchItem === item);
     if (index >= 0) {
       this._databaseItems.splice(index, 1);
@@ -662,21 +777,58 @@ export class DatabaseManager extends DisposableObject {
     this.updatePersistedDatabaseList();
 
     // Delete folder from workspace, if it is still there
-    const folderIndex = (vscode.workspace.workspaceFolders || []).findIndex(folder => item.belongsToSourceArchiveExplorerUri(folder.uri));
-    if (index >= 0) {
+    const folderIndex = (vscode.workspace.workspaceFolders || []).findIndex(
+      folder => item.belongsToSourceArchiveExplorerUri(folder.uri)
+    );
+    if (folderIndex >= 0) {
       logger.log(`Removing workspace folder at index ${folderIndex}`);
       vscode.workspace.updateWorkspaceFolders(folderIndex, 1);
     }
 
     // Delete folder from file system only if it is controlled by the extension
     if (this.isExtensionControlledLocation(item.databaseUri)) {
-      logger.log(`Deleting database from filesystem.`);
-      fs.remove(item.databaseUri.path).then(
-        () => logger.log(`Deleted '${item.databaseUri.path}'`),
-        e => logger.log(`Failed to delete '${item.databaseUri.path}'. Reason: ${e.message}`));
+      logger.log('Deleting database from filesystem.');
+      fs.remove(item.databaseUri.fsPath).then(
+        () => logger.log(`Deleted '${item.databaseUri.fsPath}'`),
+        e => logger.log(`Failed to delete '${item.databaseUri.fsPath}'. Reason: ${e.message}`));
     }
 
-    this._onDidChangeDatabaseItem.fire(undefined);
+    // Remove this database item from the allow-list
+    await this.deregisterDatabase(progress, token, item);
+
+    // note that we use undefined as the item in order to reset the entire tree
+    this._onDidChangeDatabaseItem.fire({
+      item: undefined,
+      kind: DatabaseEventKind.Remove
+    });
+  }
+
+  private async deregisterDatabase(
+    progress: ProgressCallback,
+    token: vscode.CancellationToken,
+    dbItem: DatabaseItem,
+  ) {
+    if (dbItem.contents && (await this.cli.cliConstraints.supportsDatabaseRegistration())) {
+      const databases: Dataset[] = [{
+        dbDir: dbItem.contents.datasetUri.fsPath,
+        workingSet: 'default'
+      }];
+      await this.qs.sendRequest(deregisterDatabases, { databases }, token, progress);
+    }
+  }
+
+  private async registerDatabase(
+    progress: ProgressCallback,
+    token: vscode.CancellationToken,
+    dbItem: DatabaseItem,
+  ) {
+    if (dbItem.contents && (await this.cli.cliConstraints.supportsDatabaseRegistration())) {
+      const databases: Dataset[] = [{
+        dbDir: dbItem.contents.datasetUri.fsPath,
+        workingSet: 'default'
+      }];
+      await this.qs.sendRequest(registerDatabases, { databases }, token, progress);
+    }
   }
 
   private updatePersistedCurrentDatabaseItem(): void {
@@ -690,7 +842,24 @@ export class DatabaseManager extends DisposableObject {
 
   private isExtensionControlledLocation(uri: vscode.Uri) {
     const storagePath = this.ctx.storagePath || this.ctx.globalStoragePath;
-    return uri.path.startsWith(storagePath);
+    // the uri.fsPath function on windows returns a lowercase drive letter,
+    // but storagePath will have an uppercase drive letter. Be sure to compare
+    // URIs to URIs only
+    if (storagePath) {
+      return uri.fsPath.startsWith(vscode.Uri.file(storagePath).fsPath);
+    }
+    return false;
+  }
+
+  private async getPrimaryLanguage(dbPath: string) {
+    if (!(await this.cli.cliConstraints.supportsLanguageName())) {
+      // return undefined so that we recalculate on restart until the cli is at a version that
+      // supports this feature. This recalculation is cheap since we avoid calling into the cli
+      // unless we know it can return the langauges property.
+      return undefined;
+    }
+    const dbInfo = await this.cli.resolveDatabase(dbPath);
+    return dbInfo.languages?.[0] || '';
   }
 }
 

extensions/ql-vscode/src/definitions.ts

@@ -1,204 +0,0 @@
-import * as fs from 'fs-extra';
-import * as yaml from 'js-yaml';
-import * as tmp from 'tmp';
-import * as vscode from "vscode";
-import { decodeSourceArchiveUri, zipArchiveScheme } from "./archive-filesystem-provider";
-import { ColumnKindCode, EntityValue, getResultSetSchema, LineColumnLocation, UrlValue } from "./bqrs-cli-types";
-import { CodeQLCliServer } from "./cli";
-import { DatabaseItem, DatabaseManager } from "./databases";
-import * as helpers from './helpers';
-import { CachedOperation } from './helpers';
-import * as messages from "./messages";
-import { QueryServerClient } from "./queryserver-client";
-import { compileAndRunQueryAgainstDatabase, QueryWithResults } from "./run-queries";
-
-/**
- * Run templated CodeQL queries to find definitions and references in
- * source-language files. We may eventually want to find a way to
- * generalize this to other custom queries, e.g. showing dataflow to
- * or from a selected identifier.
- */
-
-const TEMPLATE_NAME = "selectedSourceFile";
-const SELECT_QUERY_NAME = "#select";
-
-enum KeyType {
-  DefinitionQuery = 'DefinitionQuery',
-  ReferenceQuery = 'ReferenceQuery',
-}
-
-function tagOfKeyType(keyType: KeyType): string {
-  switch (keyType) {
-    case KeyType.DefinitionQuery: return "ide-contextual-queries/local-definitions";
-    case KeyType.ReferenceQuery: return "ide-contextual-queries/local-references";
-  }
-}
-
-async function resolveQueries(cli: CodeQLCliServer, qlpack: string, keyType: KeyType): Promise<string[]> {
-  const suiteFile = tmp.fileSync({ postfix: '.qls' }).name;
-  const suiteYaml = { qlpack, include: { kind: 'definitions', 'tags contain': tagOfKeyType(keyType) } };
-  await fs.writeFile(suiteFile, yaml.safeDump(suiteYaml), 'utf8');
-
-  const queries = await cli.resolveQueriesInSuite(suiteFile, helpers.getOnDiskWorkspaceFolders());
-  if (queries.length === 0) {
-    throw new Error("Couldn't find any queries for qlpack");
-  }
-  return queries;
-}
-
-async function qlpackOfDatabase(cli: CodeQLCliServer, db: DatabaseItem): Promise<string | undefined> {
-  if (db.contents === undefined)
-    return undefined;
-  const datasetPath = db.contents.datasetUri.fsPath;
-  const { qlpack } = await helpers.resolveDatasetFolder(cli, datasetPath);
-  return qlpack;
-}
-
-interface FullLocationLink extends vscode.LocationLink {
-  originUri: vscode.Uri;
-}
-
-export class TemplateQueryDefinitionProvider implements vscode.DefinitionProvider {
-  private cache: CachedOperation<vscode.LocationLink[]>;
-
-  constructor(
-    private cli: CodeQLCliServer,
-    private qs: QueryServerClient,
-    private dbm: DatabaseManager,
-  ) {
-    this.cache = new CachedOperation<vscode.LocationLink[]>(this.getDefinitions.bind(this));
-  }
-
-  async getDefinitions(uriString: string): Promise<vscode.LocationLink[]> {
-    return getLinksForUriString(this.cli, this.qs, this.dbm, uriString, KeyType.DefinitionQuery, (src, _dest) => src === uriString);
-  }
-
-  async provideDefinition(document: vscode.TextDocument, position: vscode.Position, _token: vscode.CancellationToken): Promise<vscode.LocationLink[]> {
-    const fileLinks = await this.cache.get(document.uri.toString());
-    const locLinks: vscode.LocationLink[] = [];
-    for (const link of fileLinks) {
-      if (link.originSelectionRange!.contains(position)) {
-        locLinks.push(link);
-      }
-    }
-    return locLinks;
-  }
-}
-
-export class TemplateQueryReferenceProvider implements vscode.ReferenceProvider {
-  private cache: CachedOperation<FullLocationLink[]>;
-
-  constructor(
-    private cli: CodeQLCliServer,
-    private qs: QueryServerClient,
-    private dbm: DatabaseManager,
-  ) {
-    this.cache = new CachedOperation<FullLocationLink[]>(this.getReferences.bind(this));
-  }
-
-  async getReferences(uriString: string): Promise<FullLocationLink[]> {
-    return getLinksForUriString(this.cli, this.qs, this.dbm, uriString, KeyType.ReferenceQuery, (_src, dest) => dest === uriString);
-  }
-
-  async provideReferences(document: vscode.TextDocument, position: vscode.Position, _context: vscode.ReferenceContext, _token: vscode.CancellationToken): Promise<vscode.Location[]> {
-    const fileLinks = await this.cache.get(document.uri.toString());
-    const locLinks: vscode.Location[] = [];
-    for (const link of fileLinks) {
-      if (link.targetRange!.contains(position)) {
-        locLinks.push({ range: link.originSelectionRange!, uri: link.originUri });
-      }
-    }
-    return locLinks;
-  }
-}
-
-interface FileRange {
-  file: vscode.Uri;
-  range: vscode.Range;
-}
-
-async function getLinksFromResults(results: QueryWithResults, cli: CodeQLCliServer, db: DatabaseItem, filter: (srcFile: string, destFile: string) => boolean): Promise<FullLocationLink[]> {
-  const localLinks: FullLocationLink[] = [];
-  const bqrsPath = results.query.resultsPaths.resultsPath;
-  const info = await cli.bqrsInfo(bqrsPath);
-  const selectInfo = getResultSetSchema(SELECT_QUERY_NAME, info);
-  if (selectInfo && selectInfo.columns.length == 3
-    && selectInfo.columns[0].kind == ColumnKindCode.ENTITY
-    && selectInfo.columns[1].kind == ColumnKindCode.ENTITY
-    && selectInfo.columns[2].kind == ColumnKindCode.STRING) {
-    // TODO: Page this
-    const allTuples = await cli.bqrsDecode(bqrsPath, SELECT_QUERY_NAME);
-    for (const tuple of allTuples.tuples) {
-      const src = tuple[0] as EntityValue;
-      const dest = tuple[1] as EntityValue;
-      const srcFile = src.url && fileRangeFromURI(src.url, db);
-      const destFile = dest.url && fileRangeFromURI(dest.url, db);
-      if (srcFile && destFile && filter(srcFile.file.toString(), destFile.file.toString())) {
-        localLinks.push({ targetRange: destFile.range, targetUri: destFile.file, originSelectionRange: srcFile.range, originUri: srcFile.file });
-      }
-    }
-  }
-  return localLinks;
-}
-
-async function getLinksForUriString(
-  cli: CodeQLCliServer,
-  qs: QueryServerClient,
-  dbm: DatabaseManager,
-  uriString: string,
-  keyType: KeyType,
-  filter: (src: string, dest: string) => boolean
-) {
-  const uri = decodeSourceArchiveUri(vscode.Uri.parse(uriString));
-  const sourceArchiveUri = vscode.Uri.file(uri.sourceArchiveZipPath).with({ scheme: zipArchiveScheme });
-
-  const db = dbm.findDatabaseItemBySourceArchive(sourceArchiveUri);
-  if (db) {
-    const qlpack = await qlpackOfDatabase(cli, db);
-    if (qlpack === undefined) {
-      throw new Error("Can't infer qlpack from database source archive");
-    }
-    const links: FullLocationLink[] = []
-    for (const query of await resolveQueries(cli, qlpack, keyType)) {
-      const templates: messages.TemplateDefinitions = {
-        [TEMPLATE_NAME]: {
-          values: {
-            tuples: [[{
-              stringValue: uri.pathWithinSourceArchive
-            }]]
-          }
-        }
-      };
-      const results = await compileAndRunQueryAgainstDatabase(cli, qs, db, false, vscode.Uri.file(query), templates);
-      if (results.result.resultType == messages.QueryResultType.SUCCESS) {
-        links.push(...await getLinksFromResults(results, cli, db, filter));
-      }
-    }
-    return links;
-  } else {
-    return [];
-  }
-}
-
-function fileRangeFromURI(uri: UrlValue, db: DatabaseItem): FileRange | undefined {
-  if (typeof uri === "string") {
-    return undefined;
-  } else if ('startOffset' in uri) {
-    return undefined;
-  } else {
-    const loc = uri as LineColumnLocation;
-    const range = new vscode.Range(Math.max(0, loc.startLine - 1),
-      Math.max(0, loc.startColumn - 1),
-      Math.max(0, loc.endLine - 1),
-      Math.max(0, loc.endColumn));
-    try {
-      const parsed = vscode.Uri.parse(uri.uri, true);
-      if (parsed.scheme === "file") {
-        return { file: db.resolveSourceFile(parsed.fsPath), range };
-      }
-      return undefined;
-    } catch (e) {
-      return undefined;
-    }
-  }
-}

extensions/ql-vscode/src/discovery.ts

@@ -1,4 +1,5 @@
-import { DisposableObject } from 'semmle-vscode-utils';
+import { DisposableObject } from './pure/disposable-object';
+import { logger } from './logging';
 
 /**
  * Base class for "discovery" operations, which scan the file system to find specific kinds of
@@ -9,7 +10,7 @@ export abstract class Discovery<T> extends DisposableObject {
   private retry = false;
   private discoveryInProgress = false;
 
-  constructor() {
+  constructor(private readonly name: string) {
     super();
   }
 
@@ -59,6 +60,11 @@ export abstract class Discovery<T> extends DisposableObject {
         this.update(results);
       }
     });
+
+    discoveryPromise.catch(err => {
+      logger.log(`${this.name} failed. Reason: ${err.message}`);
+    });
+
     discoveryPromise.finally(() => {
       if (this.retry) {
         // Another refresh request came in while we were still running a previous discovery

extensions/ql-vscode/src/distribution.ts

@@ -1,15 +1,21 @@
-import * as fetch from "node-fetch";
-import * as fs from "fs-extra";
-import * as os from "os";
-import * as path from "path";
-import * as unzipper from "unzipper";
-import * as url from "url";
-import { ExtensionContext, Event } from "vscode";
-import { DistributionConfig } from "./config";
-import { InvocationRateLimiter, InvocationRateLimiterResultKind, showAndLogErrorMessage } from "./helpers";
-import { logger } from "./logging";
-import * as helpers from "./helpers";
-import { getCodeQlCliVersion, tryParseVersionString, Version } from "./cli-version";
+import * as fetch from 'node-fetch';
+import * as fs from 'fs-extra';
+import * as os from 'os';
+import * as path from 'path';
+import * as semver from 'semver';
+import * as unzipper from 'unzipper';
+import * as url from 'url';
+import { ExtensionContext, Event } from 'vscode';
+import { DistributionConfig } from './config';
+import {
+  InvocationRateLimiter,
+  InvocationRateLimiterResultKind,
+  showAndLogErrorMessage,
+  showAndLogWarningMessage
+} from './helpers';
+import { logger } from './logging';
+import { getCodeQlCliVersion } from './cli-version';
+import { ProgressCallback, reportStreamProgress } from './commandRunner';
 
 /**
  * distribution.ts
@@ -24,7 +30,7 @@ import { getCodeQlCliVersion, tryParseVersionString, Version } from "./cli-versi
  * We set the default here rather than as a default config value so that this default is invoked
  * upon blanking the setting.
  */
-const DEFAULT_DISTRIBUTION_OWNER_NAME = "github";
+const DEFAULT_DISTRIBUTION_OWNER_NAME = 'github';
 
 /**
  * Default value for the repository name of the extension-managed distribution on GitHub.
@@ -32,64 +38,99 @@ const DEFAULT_DISTRIBUTION_OWNER_NAME = "github";
  * We set the default here rather than as a default config value so that this default is invoked
  * upon blanking the setting.
  */
-const DEFAULT_DISTRIBUTION_REPOSITORY_NAME = "codeql-cli-binaries";
+const DEFAULT_DISTRIBUTION_REPOSITORY_NAME = 'codeql-cli-binaries';
 
 /**
- * Version constraint for the CLI.
+ * Range of versions of the CLI that are compatible with the extension.
  *
  * This applies to both extension-managed and CLI distributions.
  */
-export const DEFAULT_DISTRIBUTION_VERSION_CONSTRAINT: VersionConstraint = {
-  description: "2.*.*",
-  isVersionCompatible: (v: Version) => {
-    return v.majorVersion === 2 && v.minorVersion >= 0
-  }
-}
+export const DEFAULT_DISTRIBUTION_VERSION_RANGE: semver.Range = new semver.Range('2.x');
 
 export interface DistributionProvider {
   getCodeQlPathWithoutVersionCheck(): Promise<string | undefined>;
   onDidChangeDistribution?: Event<void>;
+  getDistribution(): Promise<FindDistributionResult>;
 }
 
 export class DistributionManager implements DistributionProvider {
-  constructor(extensionContext: ExtensionContext, config: DistributionConfig, versionConstraint: VersionConstraint) {
-    this._config = config;
-    this._extensionSpecificDistributionManager = new ExtensionSpecificDistributionManager(extensionContext, config, versionConstraint);
-    this._onDidChangeDistribution = config.onDidChangeDistributionConfiguration;
-    this._updateCheckRateLimiter = new InvocationRateLimiter(
+
+  /**
+   * Get the name of the codeql cli installation we prefer to install, based on our current platform.
+   */
+  public static getRequiredAssetName(): string {
+    switch (os.platform()) {
+      case 'linux':
+        return 'codeql-linux64.zip';
+      case 'darwin':
+        return 'codeql-osx64.zip';
+      case 'win32':
+        return 'codeql-win64.zip';
+      default:
+        return 'codeql.zip';
+    }
+  }
+
+  constructor(
+    public readonly config: DistributionConfig,
+    private readonly versionRange: semver.Range,
+    extensionContext: ExtensionContext
+  ) {
+    this._onDidChangeDistribution = config.onDidChangeConfiguration;
+    this.extensionSpecificDistributionManager =
+      new ExtensionSpecificDistributionManager(config, versionRange, extensionContext);
+    this.updateCheckRateLimiter = new InvocationRateLimiter(
       extensionContext,
-      "extensionSpecificDistributionUpdateCheck",
-      () => this._extensionSpecificDistributionManager.checkForUpdatesToDistribution()
+      'extensionSpecificDistributionUpdateCheck',
+      () => this.extensionSpecificDistributionManager.checkForUpdatesToDistribution()
     );
-    this._versionConstraint = versionConstraint;
   }
 
   /**
    * Look up a CodeQL launcher binary.
    */
   public async getDistribution(): Promise<FindDistributionResult> {
-    const codeQlPath = await this.getCodeQlPathWithoutVersionCheck();
-    if (codeQlPath === undefined) {
+    const distribution = await this.getDistributionWithoutVersionCheck();
+    if (distribution === undefined) {
       return {
         kind: FindDistributionResultKind.NoDistribution,
       };
     }
-    const version = await getCodeQlCliVersion(codeQlPath, logger);
-    if (version !== undefined && !this._versionConstraint.isVersionCompatible(version)) {
+    const version = await getCodeQlCliVersion(distribution.codeQlPath, logger);
+    if (version === undefined) {
       return {
-        codeQlPath,
+        distribution,
+        kind: FindDistributionResultKind.UnknownCompatibilityDistribution,
+      };
+    }
+
+    /**
+     * Specifies whether prerelease versions of the CodeQL CLI should be accepted.
+     *
+     * Suppose a user sets the includePrerelease config option, obtains a prerelease, then decides
+     * they no longer want a prerelease, so unsets the includePrerelease config option.
+     * Unsetting the includePrerelease config option should trigger an update check, and this
+     * update check should present them an update that returns them back to a non-prerelease
+     * version.
+     *
+     * Therefore, we adopt the following:
+     *
+     * - If the user is managing their own CLI, they can use a prerelease without specifying the
+     * includePrerelease option.
+     * - If the user is using an extension-managed CLI, then prereleases are only accepted when the
+     * includePrerelease config option is set.
+     */
+    const includePrerelease = distribution.kind !== DistributionKind.ExtensionManaged || this.config.includePrerelease;
+
+    if (!semver.satisfies(version, this.versionRange, { includePrerelease })) {
+      return {
+        distribution,
         kind: FindDistributionResultKind.IncompatibleDistribution,
         version,
       };
     }
-    if (version === undefined) {
-      return {
-        codeQlPath,
-        kind: FindDistributionResultKind.UnknownCompatibilityDistribution,
-      }
-    }
     return {
-      codeQlPath,
+      distribution,
       kind: FindDistributionResultKind.CompatibleDistribution,
       version
     };
@@ -100,43 +141,57 @@ export class DistributionManager implements DistributionProvider {
     return result.kind !== FindDistributionResultKind.NoDistribution;
   }
 
+  public async getCodeQlPathWithoutVersionCheck(): Promise<string | undefined> {
+    const distribution = await this.getDistributionWithoutVersionCheck();
+    return distribution?.codeQlPath;
+  }
+
   /**
    * Returns the path to a possibly-compatible CodeQL launcher binary, or undefined if a binary not be found.
    */
-  public async getCodeQlPathWithoutVersionCheck(): Promise<string | undefined> {
+  async getDistributionWithoutVersionCheck(): Promise<Distribution | undefined> {
     // Check config setting, then extension specific distribution, then PATH.
-    if (this._config.customCodeQlPath) {
-      if (!await fs.pathExists(this._config.customCodeQlPath)) {
-        showAndLogErrorMessage(`The CodeQL executable path is specified as "${this._config.customCodeQlPath}" ` +
-          "by a configuration setting, but a CodeQL executable could not be found at that path. Please check " +
-          "that a CodeQL executable exists at the specified path or remove the setting.");
+    if (this.config.customCodeQlPath) {
+      if (!await fs.pathExists(this.config.customCodeQlPath)) {
+        showAndLogErrorMessage(`The CodeQL executable path is specified as "${this.config.customCodeQlPath}" ` +
+          'by a configuration setting, but a CodeQL executable could not be found at that path. Please check ' +
+          'that a CodeQL executable exists at the specified path or remove the setting.');
         return undefined;
       }
 
       // emit a warning if using a deprecated launcher and a non-deprecated launcher exists
       if (
         deprecatedCodeQlLauncherName() &&
-        this._config.customCodeQlPath.endsWith(deprecatedCodeQlLauncherName()!) &&
+        this.config.customCodeQlPath.endsWith(deprecatedCodeQlLauncherName()!) &&
         await this.hasNewLauncherName()
       ) {
         warnDeprecatedLauncher();
       }
-      return this._config.customCodeQlPath;
+      return {
+        codeQlPath: this.config.customCodeQlPath,
+        kind: DistributionKind.CustomPathConfig
+      };
     }
 
-    const extensionSpecificCodeQlPath = await this._extensionSpecificDistributionManager.getCodeQlPathWithoutVersionCheck();
+    const extensionSpecificCodeQlPath = await this.extensionSpecificDistributionManager.getCodeQlPathWithoutVersionCheck();
     if (extensionSpecificCodeQlPath !== undefined) {
-      return extensionSpecificCodeQlPath;
+      return {
+        codeQlPath: extensionSpecificCodeQlPath,
+        kind: DistributionKind.ExtensionManaged
+      };
     }
 
     if (process.env.PATH) {
       for (const searchDirectory of process.env.PATH.split(path.delimiter)) {
         const expectedLauncherPath = await getExecutableFromDirectory(searchDirectory);
         if (expectedLauncherPath) {
-          return expectedLauncherPath;
+          return {
+            codeQlPath: expectedLauncherPath,
+            kind: DistributionKind.PathEnvironmentVariable
+          };
         }
       }
-      logger.log("INFO: Could not find CodeQL on path.");
+      logger.log('INFO: Could not find CodeQL on path.');
     }
 
     return undefined;
@@ -150,13 +205,13 @@ export class DistributionManager implements DistributionProvider {
    */
   public async checkForUpdatesToExtensionManagedDistribution(
     minSecondsSinceLastUpdateCheck: number): Promise<DistributionUpdateCheckResult> {
-    const codeQlPath = await this.getCodeQlPathWithoutVersionCheck();
-    const extensionManagedCodeQlPath = await this._extensionSpecificDistributionManager.getCodeQlPathWithoutVersionCheck();
-    if (codeQlPath !== undefined && codeQlPath !== extensionManagedCodeQlPath) {
+    const distribution = await this.getDistributionWithoutVersionCheck();
+    const extensionManagedCodeQlPath = await this.extensionSpecificDistributionManager.getCodeQlPathWithoutVersionCheck();
+    if (distribution?.codeQlPath !== extensionManagedCodeQlPath) {
       // A distribution is present but it isn't managed by the extension.
       return createInvalidLocationResult();
     }
-    const updateCheckResult = await this._updateCheckRateLimiter.invokeFunctionIfIntervalElapsed(minSecondsSinceLastUpdateCheck);
+    const updateCheckResult = await this.updateCheckRateLimiter.invokeFunctionIfIntervalElapsed(minSecondsSinceLastUpdateCheck);
     switch (updateCheckResult.kind) {
       case InvocationRateLimiterResultKind.Invoked:
         return updateCheckResult.result;
@@ -170,9 +225,11 @@ export class DistributionManager implements DistributionProvider {
    *
    * Returns a failed promise if an unexpected error occurs during installation.
    */
-  public installExtensionManagedDistributionRelease(release: Release,
-    progressCallback?: helpers.ProgressCallback): Promise<void> {
-    return this._extensionSpecificDistributionManager.installDistributionRelease(release, progressCallback);
+  public installExtensionManagedDistributionRelease(
+    release: Release,
+    progressCallback?: ProgressCallback
+  ): Promise<void> {
+    return this.extensionSpecificDistributionManager.installDistributionRelease(release, progressCallback);
   }
 
   public get onDidChangeDistribution(): Event<void> | undefined {
@@ -185,27 +242,27 @@ export class DistributionManager implements DistributionProvider {
    * installation. False otherwise.
    */
   private async hasNewLauncherName(): Promise<boolean> {
-    if (!this._config.customCodeQlPath) {
+    if (!this.config.customCodeQlPath) {
       // not managed externally
       return false;
     }
-    const dir = path.dirname(this._config.customCodeQlPath);
+    const dir = path.dirname(this.config.customCodeQlPath);
     const newLaunderPath = path.join(dir, codeQlLauncherName());
     return await fs.pathExists(newLaunderPath);
   }
 
-  private readonly _config: DistributionConfig;
-  private readonly _extensionSpecificDistributionManager: ExtensionSpecificDistributionManager;
-  private readonly _updateCheckRateLimiter: InvocationRateLimiter<DistributionUpdateCheckResult>;
+  private readonly extensionSpecificDistributionManager: ExtensionSpecificDistributionManager;
+  private readonly updateCheckRateLimiter: InvocationRateLimiter<DistributionUpdateCheckResult>;
   private readonly _onDidChangeDistribution: Event<void> | undefined;
-  private readonly _versionConstraint: VersionConstraint;
 }
 
 class ExtensionSpecificDistributionManager {
-  constructor(extensionContext: ExtensionContext, config: DistributionConfig, versionConstraint: VersionConstraint) {
-    this._extensionContext = extensionContext;
-    this._config = config;
-    this._versionConstraint = versionConstraint;
+  constructor(
+    private readonly config: DistributionConfig,
+    private readonly versionRange: semver.Range,
+    private readonly extensionContext: ExtensionContext
+  ) {
+    /**/
   }
 
   public async getCodeQlPathWithoutVersionCheck(): Promise<string | undefined> {
@@ -219,7 +276,7 @@ class ExtensionSpecificDistributionManager {
       try {
         await this.removeDistribution();
       } catch (e) {
-        logger.log("WARNING: Tried to remove corrupted CodeQL CLI at " +
+        logger.log('WARNING: Tried to remove corrupted CodeQL CLI at ' +
           `${this.getDistributionStoragePath()} but encountered an error: ${e}.`);
       }
     }
@@ -253,14 +310,14 @@ class ExtensionSpecificDistributionManager {
    * Returns a failed promise if an unexpected error occurs during installation.
    */
   public async installDistributionRelease(release: Release,
-    progressCallback?: helpers.ProgressCallback): Promise<void> {
+    progressCallback?: ProgressCallback): Promise<void> {
     await this.downloadDistribution(release, progressCallback);
     // Store the installed release within the global extension state.
     this.storeInstalledRelease(release);
   }
 
   private async downloadDistribution(release: Release,
-    progressCallback?: helpers.ProgressCallback): Promise<void> {
+    progressCallback?: ProgressCallback): Promise<void> {
     try {
       await this.removeDistribution();
     } catch (e) {
@@ -268,40 +325,32 @@ class ExtensionSpecificDistributionManager {
         `but encountered an error: ${e}.`);
     }
 
-    const assetStream = await this.createReleasesApiConsumer().streamBinaryContentOfAsset(release.assets[0]);
-    const tmpDirectory = await fs.mkdtemp(path.join(os.tmpdir(), "vscode-codeql"));
+    // Filter assets to the unique one that we require.
+    const requiredAssetName = DistributionManager.getRequiredAssetName();
+    const assets = release.assets.filter(asset => asset.name === requiredAssetName);
+    if (assets.length === 0) {
+      throw new Error(`Invariant violation: chose a release to install that didn't have ${requiredAssetName}`);
+    }
+    if (assets.length > 1) {
+      logger.log('WARNING: chose a release with more than one asset to install, found ' +
+        assets.map(asset => asset.name).join(', '));
+    }
+
+    const assetStream = await this.createReleasesApiConsumer().streamBinaryContentOfAsset(assets[0]);
+    const tmpDirectory = await fs.mkdtemp(path.join(os.tmpdir(), 'vscode-codeql'));
 
     try {
-      const archivePath = path.join(tmpDirectory, "distributionDownload.zip");
+      const archivePath = path.join(tmpDirectory, 'distributionDownload.zip');
       const archiveFile = fs.createWriteStream(archivePath);
 
-      const contentLength = assetStream.headers.get("content-length");
-      let numBytesDownloaded = 0;
-
-      if (progressCallback && contentLength !== null) {
-        const totalNumBytes = parseInt(contentLength, 10);
-        const bytesToDisplayMB = (numBytes: number): string => `${(numBytes / (1024 * 1024)).toFixed(1)} MB`;
-        const updateProgress = (): void => {
-          progressCallback({
-            step: numBytesDownloaded,
-            maxStep: totalNumBytes,
-            message: `Downloading CodeQL CLI… [${bytesToDisplayMB(numBytesDownloaded)} of ${bytesToDisplayMB(totalNumBytes)}]`,
-          });
-        };
-
-        // Display the progress straight away rather than waiting for the first chunk.
-        updateProgress();
-
-        assetStream.body.on("data", data => {
-          numBytesDownloaded += data.length;
-          updateProgress();
-        });
-      }
+      const contentLength = assetStream.headers.get('content-length');
+      const totalNumBytes = contentLength ? parseInt(contentLength, 10) : undefined;
+      reportStreamProgress(assetStream.body, 'Downloading CodeQL CLI…', totalNumBytes, progressCallback);
 
       await new Promise((resolve, reject) =>
         assetStream.body.pipe(archiveFile)
-          .on("finish", resolve)
-          .on("error", reject)
+          .on('finish', resolve)
+          .on('error', reject)
       );
 
       await this.bumpDistributionFolderIndex();
@@ -326,31 +375,45 @@ class ExtensionSpecificDistributionManager {
   }
 
   private async getLatestRelease(): Promise<Release> {
-    const release = await this.createReleasesApiConsumer().getLatestRelease(this._versionConstraint, this._config.includePrerelease);
-    if (release.assets.length !== 1) {
-      throw new Error("Release had an unexpected number of assets");
-    }
-    return release;
+    const requiredAssetName = DistributionManager.getRequiredAssetName();
+    logger.log(`Searching for latest release including ${requiredAssetName}.`);
+    return this.createReleasesApiConsumer().getLatestRelease(
+      this.versionRange,
+      this.config.includePrerelease,
+      release => {
+        const matchingAssets = release.assets.filter(asset => asset.name === requiredAssetName);
+        if (matchingAssets.length === 0) {
+          // For example, this could be a release with no platform-specific assets.
+          logger.log(`INFO: Ignoring a release with no assets named ${requiredAssetName}`);
+          return false;
+        }
+        if (matchingAssets.length > 1) {
+          logger.log(`WARNING: Ignoring a release with more than one asset named ${requiredAssetName}`);
+          return false;
+        }
+        return true;
+      }
+    );
   }
 
   private createReleasesApiConsumer(): ReleasesApiConsumer {
-    const ownerName = this._config.ownerName ? this._config.ownerName : DEFAULT_DISTRIBUTION_OWNER_NAME;
-    const repositoryName = this._config.repositoryName ? this._config.repositoryName : DEFAULT_DISTRIBUTION_REPOSITORY_NAME;
-    return new ReleasesApiConsumer(ownerName, repositoryName, this._config.personalAccessToken);
+    const ownerName = this.config.ownerName ? this.config.ownerName : DEFAULT_DISTRIBUTION_OWNER_NAME;
+    const repositoryName = this.config.repositoryName ? this.config.repositoryName : DEFAULT_DISTRIBUTION_REPOSITORY_NAME;
+    return new ReleasesApiConsumer(ownerName, repositoryName, this.config.personalAccessToken);
   }
 
   private async bumpDistributionFolderIndex(): Promise<void> {
-    const index = this._extensionContext.globalState.get(
+    const index = this.extensionContext.globalState.get(
       ExtensionSpecificDistributionManager._currentDistributionFolderIndexStateKey, 0);
-    await this._extensionContext.globalState.update(
+    await this.extensionContext.globalState.update(
       ExtensionSpecificDistributionManager._currentDistributionFolderIndexStateKey, index + 1);
   }
 
   private getDistributionStoragePath(): string {
     // Use an empty string for the initial distribution for backwards compatibility.
-    const distributionFolderIndex = this._extensionContext.globalState.get(
-      ExtensionSpecificDistributionManager._currentDistributionFolderIndexStateKey, 0) || "";
-    return path.join(this._extensionContext.globalStoragePath,
+    const distributionFolderIndex = this.extensionContext.globalState.get(
+      ExtensionSpecificDistributionManager._currentDistributionFolderIndexStateKey, 0) || '';
+    return path.join(this.extensionContext.globalStoragePath,
       ExtensionSpecificDistributionManager._currentDistributionFolderBaseName + distributionFolderIndex);
   }
 
@@ -360,37 +423,33 @@ class ExtensionSpecificDistributionManager {
   }
 
   private getInstalledRelease(): Release | undefined {
-    return this._extensionContext.globalState.get(ExtensionSpecificDistributionManager._installedReleaseStateKey);
+    return this.extensionContext.globalState.get(ExtensionSpecificDistributionManager._installedReleaseStateKey);
   }
 
   private async storeInstalledRelease(release: Release | undefined): Promise<void> {
-    await this._extensionContext.globalState.update(ExtensionSpecificDistributionManager._installedReleaseStateKey, release);
+    await this.extensionContext.globalState.update(ExtensionSpecificDistributionManager._installedReleaseStateKey, release);
   }
 
-  private readonly _config: DistributionConfig;
-  private readonly _extensionContext: ExtensionContext;
-  private readonly _versionConstraint: VersionConstraint;
-
-  private static readonly _currentDistributionFolderBaseName = "distribution";
-  private static readonly _currentDistributionFolderIndexStateKey = "distributionFolderIndex";
-  private static readonly _installedReleaseStateKey = "distributionRelease";
-  private static readonly _codeQlExtractedFolderName = "codeql";
+  private static readonly _currentDistributionFolderBaseName = 'distribution';
+  private static readonly _currentDistributionFolderIndexStateKey = 'distributionFolderIndex';
+  private static readonly _installedReleaseStateKey = 'distributionRelease';
+  private static readonly _codeQlExtractedFolderName = 'codeql';
 }
 
 export class ReleasesApiConsumer {
   constructor(ownerName: string, repoName: string, personalAccessToken?: string) {
     // Specify version of the GitHub API
-    this._defaultHeaders["accept"] = "application/vnd.github.v3+json";
+    this._defaultHeaders['accept'] = 'application/vnd.github.v3+json';
 
     if (personalAccessToken) {
-      this._defaultHeaders["authorization"] = `token ${personalAccessToken}`;
+      this._defaultHeaders['authorization'] = `token ${personalAccessToken}`;
     }
 
     this._ownerName = ownerName;
     this._repoName = repoName;
   }
 
-  public async getLatestRelease(versionConstraint: VersionConstraint, includePrerelease = false): Promise<Release> {
+  public async getLatestRelease(versionRange: semver.Range, includePrerelease = false, additionalCompatibilityCheck?: (release: GithubRelease) => boolean): Promise<Release> {
     const apiPath = `/repos/${this._ownerName}/${this._repoName}/releases`;
     const allReleases: GithubRelease[] = await (await this.makeApiCall(apiPath)).json();
     const compatibleReleases = allReleases.filter(release => {
@@ -398,24 +457,24 @@ export class ReleasesApiConsumer {
         return false;
       }
 
-      const version = tryParseVersionString(release.tag_name);
-      if (version === undefined || !versionConstraint.isVersionCompatible(version)) {
+      const version = semver.parse(release.tag_name);
+      if (version === null || !semver.satisfies(version, versionRange, { includePrerelease })) {
         return false;
       }
 
-      return true;
+      return !additionalCompatibilityCheck || additionalCompatibilityCheck(release);
     });
-    // tryParseVersionString must succeed due to the previous filtering step
+    // Tag names must all be parsable to semvers due to the previous filtering step.
     const latestRelease = compatibleReleases.sort((a, b) => {
-      const versionComparison = versionCompare(tryParseVersionString(b.tag_name)!, tryParseVersionString(a.tag_name)!);
-      if (versionComparison === 0) {
-        return b.created_at.localeCompare(a.created_at);
+      const versionComparison = semver.compare(semver.parse(b.tag_name)!, semver.parse(a.tag_name)!);
+      if (versionComparison !== 0) {
+        return versionComparison;
       }
-      return versionComparison;
+      return b.created_at.localeCompare(a.created_at, 'en-US');
     })[0];
     if (latestRelease === undefined) {
-      throw new Error("No compatible CodeQL CLI releases were found. " +
-        "Please check that the CodeQL extension is up to date.");
+      throw new Error('No compatible CodeQL CLI releases were found. ' +
+        'Please check that the CodeQL extension is up to date.');
     }
     const assets: ReleaseAsset[] = latestRelease.assets.map(asset => {
       return {
@@ -437,7 +496,7 @@ export class ReleasesApiConsumer {
     const apiPath = `/repos/${this._ownerName}/${this._repoName}/releases/assets/${asset.id}`;
 
     return await this.makeApiCall(apiPath, {
-      "accept": "application/octet-stream"
+      'accept': 'application/octet-stream'
     });
   }
 
@@ -447,7 +506,7 @@ export class ReleasesApiConsumer {
 
     if (!response.ok) {
       // Check for rate limiting
-      const rateLimitResetValue = response.headers.get("X-RateLimit-Reset");
+      const rateLimitResetValue = response.headers.get('X-RateLimit-Reset');
       if (response.status === 403 && rateLimitResetValue) {
         const secondsToMillisecondsFactor = 1000;
         const rateLimitResetDate = new Date(parseInt(rateLimitResetValue, 10) * secondsToMillisecondsFactor);
@@ -464,23 +523,23 @@ export class ReleasesApiConsumer {
     redirectCount = 0): Promise<fetch.Response> {
     const response = await fetch.default(requestUrl, {
       headers,
-      redirect: "manual"
+      redirect: 'manual'
     });
 
-    const redirectUrl = response.headers.get("location");
+    const redirectUrl = response.headers.get('location');
     if (isRedirectStatusCode(response.status) && redirectUrl && redirectCount < ReleasesApiConsumer._maxRedirects) {
       const parsedRedirectUrl = url.parse(redirectUrl);
-      if (parsedRedirectUrl.protocol != "https:") {
-        throw new Error("Encountered a non-https redirect, rejecting");
+      if (parsedRedirectUrl.protocol != 'https:') {
+        throw new Error('Encountered a non-https redirect, rejecting');
       }
-      if (parsedRedirectUrl.host != "api.github.com") {
+      if (parsedRedirectUrl.host != 'api.github.com') {
         // Remove authorization header if we are redirected outside of the GitHub API.
         //
         // This is necessary to stream release assets since AWS fails if more than one auth
         // mechanism is provided.
-        delete headers["authorization"];
+        delete headers['authorization'];
       }
-      return await this.makeRawRequest(redirectUrl, headers, redirectCount + 1)
+      return await this.makeRawRequest(redirectUrl, headers, redirectCount + 1);
     }
 
     return response;
@@ -490,7 +549,7 @@ export class ReleasesApiConsumer {
   private readonly _ownerName: string;
   private readonly _repoName: string;
 
-  private static readonly _apiBase = "https://api.github.com";
+  private static readonly _apiBase = 'https://api.github.com';
   private static readonly _maxRedirects = 20;
 }
 
@@ -511,35 +570,12 @@ export async function extractZipArchive(archivePath: string, outPath: string): P
   }));
 }
 
-/**
- * Comparison of semantic versions.
- *
- * Returns a positive number if a is greater than b.
- * Returns 0 if a equals b.
- * Returns a negative number if a is less than b.
- */
-export function versionCompare(a: Version, b: Version): number {
-  if (a.majorVersion !== b.majorVersion) {
-    return a.majorVersion - b.majorVersion;
-  }
-  if (a.minorVersion !== b.minorVersion) {
-    return a.minorVersion - b.minorVersion;
-  }
-  if (a.patchVersion !== b.patchVersion) {
-    return a.patchVersion - b.patchVersion;
-  }
-  if (a.prereleaseVersion !== undefined && b.prereleaseVersion !== undefined) {
-    return a.prereleaseVersion.localeCompare(b.prereleaseVersion);
-  }
-  return 0;
-}
-
-function codeQlLauncherName(): string {
-  return (os.platform() === "win32") ? "codeql.exe" : "codeql";
+export function codeQlLauncherName(): string {
+  return (os.platform() === 'win32') ? 'codeql.exe' : 'codeql';
 }
 
 function deprecatedCodeQlLauncherName(): string | undefined {
-  return (os.platform() === "win32") ? "codeql.cmd" : undefined;
+  return (os.platform() === 'win32') ? 'codeql.cmd' : undefined;
 }
 
 function isRedirectStatusCode(statusCode: number): boolean {
@@ -550,6 +586,17 @@ function isRedirectStatusCode(statusCode: number): boolean {
  * Types and helper functions relating to those types.
  */
 
+export enum DistributionKind {
+  CustomPathConfig,
+  ExtensionManaged,
+  PathEnvironmentVariable
+}
+
+export interface Distribution {
+  codeQlPath: string;
+  kind: DistributionKind;
+}
+
 export enum FindDistributionResultKind {
   CompatibleDistribution,
   UnknownCompatibilityDistribution,
@@ -563,21 +610,27 @@ export type FindDistributionResult =
   | IncompatibleDistributionResult
   | NoDistributionResult;
 
-interface CompatibleDistributionResult {
-  codeQlPath: string;
-  kind: FindDistributionResultKind.CompatibleDistribution;
-  version: Version;
+/**
+ * A result representing a distribution of the CodeQL CLI that may or may not be compatible with
+ * the extension.
+ */
+interface DistributionResult {
+  distribution: Distribution;
+  kind: FindDistributionResultKind;
 }
 
-interface UnknownCompatibilityDistributionResult {
-  codeQlPath: string;
+interface CompatibleDistributionResult extends DistributionResult {
+  kind: FindDistributionResultKind.CompatibleDistribution;
+  version: semver.SemVer;
+}
+
+interface UnknownCompatibilityDistributionResult extends DistributionResult {
   kind: FindDistributionResultKind.UnknownCompatibilityDistribution;
 }
 
-interface IncompatibleDistributionResult {
-  codeQlPath: string;
+interface IncompatibleDistributionResult extends DistributionResult {
   kind: FindDistributionResultKind.IncompatibleDistribution;
-  version: Version;
+  version: semver.SemVer;
 }
 
 interface NoDistributionResult {
@@ -655,13 +708,15 @@ export async function getExecutableFromDirectory(directory: string, warnWhenNotF
   }
   if (warnWhenNotFound) {
     logger.log(`WARNING: Expected to find a CodeQL CLI executable at ${expectedLauncherPath} but one was not found. ` +
-      "Will try PATH.");
+      'Will try PATH.');
   }
   return undefined;
 }
 
 function warnDeprecatedLauncher() {
-  helpers.showAndLogWarningMessage(
+
+  showAndLogWarningMessage(
+
     `The "${deprecatedCodeQlLauncherName()!}" launcher has been deprecated and will be removed in a future version. ` +
     `Please use "${codeQlLauncherName()}" instead. It is recommended to update to the latest CodeQL binaries.`
   );
@@ -717,7 +772,7 @@ export interface GithubRelease {
   assets: GithubReleaseAsset[];
 
   /**
-   * The creation date of the release on GitHub.
+   * The creation date of the release on GitHub, in ISO 8601 format.
    */
   created_at: string;
 
@@ -762,11 +817,6 @@ export interface GithubReleaseAsset {
   size: number;
 }
 
-interface VersionConstraint {
-  description: string;
-  isVersionCompatible(version: Version): boolean;
-}
-
 export class GithubApiError extends Error {
   constructor(public status: number, public body: string) {
     super(`API call failed with status code ${status}, body: ${body}`);

extensions/ql-vscode/src/extension.ts

@@ -1,26 +1,74 @@
-import { commands, Disposable, ExtensionContext, extensions, languages, ProgressLocation, ProgressOptions, Uri, window as Window } from 'vscode';
+import {
+  CancellationToken,
+  commands,
+  Disposable,
+  ExtensionContext,
+  extensions,
+  languages,
+  ProgressLocation,
+  ProgressOptions,
+  Uri,
+  window as Window,
+  env,
+  window
+} from 'vscode';
 import { LanguageClient } from 'vscode-languageclient';
+import * as os from 'os';
+import * as path from 'path';
 import { testExplorerExtensionId, TestHub } from 'vscode-test-adapter-api';
+
+import { AstViewer } from './astViewer';
 import * as archiveFilesystemProvider from './archive-filesystem-provider';
-import { CodeQLCliServer } from './cli';
-import { DistributionConfigListener, QueryHistoryConfigListener, QueryServerConfigListener, EXPERIMENTAL_FEATURES_SETTING } from './config';
+import { CodeQLCliServer, CliVersionConstraint } from './cli';
+import {
+  CliConfigListener,
+  DistributionConfigListener,
+  MAX_QUERIES,
+  QueryHistoryConfigListener,
+  QueryServerConfigListener
+} from './config';
+import * as languageSupport from './languageSupport';
 import { DatabaseManager } from './databases';
 import { DatabaseUI } from './databases-ui';
-import { TemplateQueryDefinitionProvider, TemplateQueryReferenceProvider } from './definitions';
-import { DEFAULT_DISTRIBUTION_VERSION_CONSTRAINT, DistributionManager, DistributionUpdateCheckResultKind, FindDistributionResult, FindDistributionResultKind, GithubApiError, GithubRateLimitedError } from './distribution';
+import {
+  TemplateQueryDefinitionProvider,
+  TemplateQueryReferenceProvider,
+  TemplatePrintAstProvider
+} from './contextual/templateProvider';
+import {
+  DEFAULT_DISTRIBUTION_VERSION_RANGE,
+  DistributionKind,
+  DistributionManager,
+  DistributionUpdateCheckResultKind,
+  FindDistributionResult,
+  FindDistributionResultKind,
+  GithubApiError,
+  GithubRateLimitedError
+} from './distribution';
 import * as helpers from './helpers';
-import { assertNever } from './helpers-pure';
+import { assertNever } from './pure/helpers-pure';
 import { spawnIdeServer } from './ide-server';
-import { InterfaceManager, WebviewReveal } from './interface';
+import { InterfaceManager } from './interface';
+import { WebviewReveal } from './interface-utils';
 import { ideServerLogger, logger, queryServerLogger } from './logging';
 import { QueryHistoryManager } from './query-history';
 import { CompletedQuery } from './query-results';
 import * as qsClient from './queryserver-client';
 import { displayQuickQuery } from './quick-query';
-import { compileAndRunQueryAgainstDatabase, tmpDirDisposal, UserCancellationException } from './run-queries';
+import { compileAndRunQueryAgainstDatabase, tmpDirDisposal } from './run-queries';
 import { QLTestAdapterFactory } from './test-adapter';
 import { TestUIService } from './test-ui';
-import promptFetchDatabase from './databaseFetcher';
+import { CompareInterfaceManager } from './compare/compare-interface';
+import { gatherQlFiles } from './pure/files';
+import { initializeTelemetry } from './telemetry';
+import {
+  commandRunner,
+  commandRunnerWithProgress,
+  ProgressCallback,
+  withProgress,
+  ProgressUpdate
+} from './commandRunner';
+import { CodeQlStatusBarHandler } from './status-bar';
 
 /**
  * extension.ts
@@ -49,18 +97,19 @@ const errorStubs: Disposable[] = [];
  */
 let isInstallingOrUpdatingDistribution = false;
 
+const extensionId = 'GitHub.vscode-codeql';
+const extension = extensions.getExtension(extensionId);
+
 /**
  * If the user tries to execute vscode commands after extension activation is failed, give
  * a sensible error message.
  *
  * @param excludedCommands List of commands for which we should not register error stubs.
  */
-function registerErrorStubs(excludedCommands: string[], stubGenerator: (command: string) => () => void): void {
+function registerErrorStubs(excludedCommands: string[], stubGenerator: (command: string) => () => Promise<void>): void {
   // Remove existing stubs
   errorStubs.forEach(stub => stub.dispose());
 
-  const extensionId = 'GitHub.vscode-codeql'; // TODO: Is there a better way of obtaining this?
-  const extension = extensions.getExtension(extensionId);
   if (extension === undefined) {
     throw new Error(`Can't find extension ${extensionId}`);
   }
@@ -70,25 +119,55 @@ function registerErrorStubs(excludedCommands: string[], stubGenerator: (command:
 
   stubbedCommands.forEach(command => {
     if (excludedCommands.indexOf(command) === -1) {
-      errorStubs.push(commands.registerCommand(command, stubGenerator(command)));
+      errorStubs.push(commandRunner(command, stubGenerator(command)));
     }
   });
 }
 
-export async function activate(ctx: ExtensionContext): Promise<void> {
-  logger.log('Starting CodeQL extension');
+/**
+ * The publicly available interface for this extension. This is to
+ * be used in our tests.
+ */
+export interface CodeQLExtensionInterface {
+  readonly ctx: ExtensionContext;
+  readonly cliServer: CodeQLCliServer;
+  readonly qs: qsClient.QueryServerClient;
+  readonly distributionManager: DistributionManager;
+  readonly databaseManager: DatabaseManager;
+  readonly databaseUI: DatabaseUI;
+  readonly dispose: () => void;
+}
 
-  initializeLogging(ctx);
+/**
+ * Returns the CodeQLExtensionInterface, or an empty object if the interface is not
+ * available after activation is complete. This will happen if there is no cli
+ * installed when the extension starts. Downloading and installing the cli
+ * will happen at a later time.
+ *
+ * @param ctx The extension context
+ *
+ * @returns CodeQLExtensionInterface
+ */
+export async function activate(ctx: ExtensionContext): Promise<CodeQLExtensionInterface | {}> {
+  logger.log(`Starting ${extensionId} extension`);
+  if (extension === undefined) {
+    throw new Error(`Can't find extension ${extensionId}`);
+  }
 
   const distributionConfigListener = new DistributionConfigListener();
+  initializeLogging(ctx);
+  await initializeTelemetry(extension, ctx);
+  languageSupport.install();
+
   ctx.subscriptions.push(distributionConfigListener);
-  const distributionManager = new DistributionManager(ctx, distributionConfigListener, DEFAULT_DISTRIBUTION_VERSION_CONSTRAINT);
+  const codeQlVersionRange = DEFAULT_DISTRIBUTION_VERSION_RANGE;
+  const distributionManager = new DistributionManager(distributionConfigListener, codeQlVersionRange, ctx);
 
-  const shouldUpdateOnNextActivationKey = "shouldUpdateOnNextActivation";
+  const shouldUpdateOnNextActivationKey = 'shouldUpdateOnNextActivation';
 
-  registerErrorStubs([checkForUpdatesCommand], command => () => {
+  registerErrorStubs([checkForUpdatesCommand], command => (async () => {
     helpers.showAndLogErrorMessage(`Can't execute ${command}: waiting to finish loading CodeQL CLI.`);
-  });
+  }));
 
   interface DistributionUpdateConfig {
     isUserInitiated: boolean;
@@ -107,7 +186,7 @@ export async function activate(ctx: ExtensionContext): Promise<void> {
 
     switch (result.kind) {
       case DistributionUpdateCheckResultKind.AlreadyCheckedRecentlyResult:
-        logger.log("Didn't perform CodeQL CLI update check since a check was already performed within the previous " +
+        logger.log('Didn\'t perform CodeQL CLI update check since a check was already performed within the previous ' +
           `${minSecondsSinceLastUpdateCheck} seconds.`);
         break;
       case DistributionUpdateCheckResultKind.AlreadyUpToDate:
@@ -126,11 +205,11 @@ export async function activate(ctx: ExtensionContext): Promise<void> {
           }
         } else {
           const progressOptions: ProgressOptions = {
-            location: ProgressLocation.Notification,
             title: progressTitle,
-            cancellable: false,
+            location: ProgressLocation.Notification,
           };
-          await helpers.withProgress(progressOptions, progress =>
+
+          await withProgress(progressOptions, progress =>
             distributionManager.installExtensionManagedDistributionRelease(result.updatedRelease, progress));
 
           await ctx.globalState.update(shouldUpdateOnNextActivationKey, false);
@@ -144,16 +223,16 @@ export async function activate(ctx: ExtensionContext): Promise<void> {
 
   async function installOrUpdateDistribution(config: DistributionUpdateConfig): Promise<void> {
     if (isInstallingOrUpdatingDistribution) {
-      throw new Error("Already installing or updating CodeQL CLI");
+      throw new Error('Already installing or updating CodeQL CLI');
     }
     isInstallingOrUpdatingDistribution = true;
     const codeQlInstalled = await distributionManager.getCodeQlPathWithoutVersionCheck() !== undefined;
     const willUpdateCodeQl = ctx.globalState.get(shouldUpdateOnNextActivationKey);
     const messageText = willUpdateCodeQl
-      ? "Updating CodeQL CLI"
+      ? 'Updating CodeQL CLI'
       : codeQlInstalled
-        ? "Checking for updates to CodeQL CLI"
-        : "Installing CodeQL CLI";
+        ? 'Checking for updates to CodeQL CLI'
+        : 'Installing CodeQL CLI';
 
     try {
       await installOrUpdateDistributionWithProgressTitle(messageText, config);
@@ -162,12 +241,12 @@ export async function activate(ctx: ExtensionContext): Promise<void> {
       // or updating the distribution.
       const alertFunction = (codeQlInstalled && !config.isUserInitiated) ?
         helpers.showAndLogWarningMessage : helpers.showAndLogErrorMessage;
-      const taskDescription = (willUpdateCodeQl ? "update" :
-        codeQlInstalled ? "check for updates to" : "install") + " CodeQL CLI";
+      const taskDescription = (willUpdateCodeQl ? 'update' :
+        codeQlInstalled ? 'check for updates to' : 'install') + ' CodeQL CLI';
 
       if (e instanceof GithubRateLimitedError) {
         alertFunction(`Rate limited while trying to ${taskDescription}. Please try again after ` +
-          `your rate limit window resets at ${e.rateLimitResetDate.toLocaleString()}.`);
+          `your rate limit window resets at ${e.rateLimitResetDate.toLocaleString(env.language)}.`);
       } else if (e instanceof GithubApiError) {
         alertFunction(`Encountered GitHub API error while trying to ${taskDescription}. ` + e);
       }
@@ -181,17 +260,31 @@ export async function activate(ctx: ExtensionContext): Promise<void> {
     const result = await distributionManager.getDistribution();
     switch (result.kind) {
       case FindDistributionResultKind.CompatibleDistribution:
-        logger.log(`Found compatible version of CodeQL CLI (version ${result.version.rawString})`);
+        logger.log(`Found compatible version of CodeQL CLI (version ${result.version.raw})`);
         break;
-      case FindDistributionResultKind.IncompatibleDistribution:
-        helpers.showAndLogWarningMessage("The current version of the CodeQL CLI is incompatible with this extension.");
+      case FindDistributionResultKind.IncompatibleDistribution: {
+        const fixGuidanceMessage = (() => {
+          switch (result.distribution.kind) {
+            case DistributionKind.ExtensionManaged:
+              return 'Please update the CodeQL CLI by running the "CodeQL: Check for CLI Updates" command.';
+            case DistributionKind.CustomPathConfig:
+              return `Please update the \"CodeQL CLI Executable Path\" setting to point to a CLI in the version range ${codeQlVersionRange}.`;
+            case DistributionKind.PathEnvironmentVariable:
+              return `Please update the CodeQL CLI on your PATH to a version compatible with ${codeQlVersionRange}, or ` +
+                `set the \"CodeQL CLI Executable Path\" setting to the path of a CLI version compatible with ${codeQlVersionRange}.`;
+          }
+        })();
+
+        helpers.showAndLogWarningMessage(`The current version of the CodeQL CLI (${result.version.raw}) ` +
+          'is incompatible with this extension. ' + fixGuidanceMessage);
         break;
+      }
       case FindDistributionResultKind.UnknownCompatibilityDistribution:
-        helpers.showAndLogWarningMessage("Compatibility with the configured CodeQL CLI could not be determined. " +
-          "You may experience problems using the extension.");
+        helpers.showAndLogWarningMessage('Compatibility with the configured CodeQL CLI could not be determined. ' +
+          'You may experience problems using the extension.');
         break;
       case FindDistributionResultKind.NoDistribution:
-        helpers.showAndLogErrorMessage("The CodeQL CLI could not be found.");
+        helpers.showAndLogErrorMessage('The CodeQL CLI could not be found.');
         break;
       default:
         assertNever(result);
@@ -199,22 +292,30 @@ export async function activate(ctx: ExtensionContext): Promise<void> {
     return result;
   }
 
-  async function installOrUpdateThenTryActivate(config: DistributionUpdateConfig): Promise<void> {
+  async function installOrUpdateThenTryActivate(
+    config: DistributionUpdateConfig
+  ): Promise<CodeQLExtensionInterface | {}> {
+
     await installOrUpdateDistribution(config);
 
     // Display the warnings even if the extension has already activated.
     const distributionResult = await getDistributionDisplayingDistributionWarnings();
-
+    let extensionInterface: CodeQLExtensionInterface | {} = {};
     if (!beganMainExtensionActivation && distributionResult.kind !== FindDistributionResultKind.NoDistribution) {
-      await activateWithInstalledDistribution(ctx, distributionManager);
+      extensionInterface = await activateWithInstalledDistribution(
+        ctx,
+        distributionManager,
+        distributionConfigListener
+      );
+
     } else if (distributionResult.kind === FindDistributionResultKind.NoDistribution) {
       registerErrorStubs([checkForUpdatesCommand], command => async () => {
-        const installActionName = "Install CodeQL CLI";
+        const installActionName = 'Install CodeQL CLI';
         const chosenAction = await helpers.showAndLogErrorMessage(`Can't execute ${command}: missing CodeQL CLI.`, {
           items: [installActionName]
         });
         if (chosenAction === installActionName) {
-          installOrUpdateThenTryActivate({
+          await installOrUpdateThenTryActivate({
             isUserInitiated: true,
             shouldDisplayMessageWhenNoUpdates: false,
             allowAutoUpdating: true
@@ -222,20 +323,21 @@ export async function activate(ctx: ExtensionContext): Promise<void> {
         }
       });
     }
+    return extensionInterface;
   }
 
-  ctx.subscriptions.push(distributionConfigListener.onDidChangeDistributionConfiguration(() => installOrUpdateThenTryActivate({
+  ctx.subscriptions.push(distributionConfigListener.onDidChangeConfiguration(() => installOrUpdateThenTryActivate({
     isUserInitiated: true,
     shouldDisplayMessageWhenNoUpdates: false,
     allowAutoUpdating: true
   })));
-  ctx.subscriptions.push(commands.registerCommand(checkForUpdatesCommand, () => installOrUpdateThenTryActivate({
+  ctx.subscriptions.push(commandRunner(checkForUpdatesCommand, () => installOrUpdateThenTryActivate({
     isUserInitiated: true,
     shouldDisplayMessageWhenNoUpdates: true,
     allowAutoUpdating: true
   })));
 
-  await installOrUpdateThenTryActivate({
+  return await installOrUpdateThenTryActivate({
     isUserInitiated: !!ctx.globalState.get(shouldUpdateOnNextActivationKey),
     shouldDisplayMessageWhenNoUpdates: false,
 
@@ -245,80 +347,183 @@ export async function activate(ctx: ExtensionContext): Promise<void> {
   });
 }
 
-async function activateWithInstalledDistribution(ctx: ExtensionContext, distributionManager: DistributionManager): Promise<void> {
+async function activateWithInstalledDistribution(
+  ctx: ExtensionContext,
+  distributionManager: DistributionManager,
+  distributionConfigListener: DistributionConfigListener
+): Promise<CodeQLExtensionInterface> {
   beganMainExtensionActivation = true;
   // Remove any error stubs command handlers left over from first part
   // of activation.
-  errorStubs.forEach(stub => stub.dispose());
+  errorStubs.forEach((stub) => stub.dispose());
 
-  const qlConfigurationListener = await QueryServerConfigListener.createQueryServerConfigListener(distributionManager);
+  logger.log('Initializing configuration listener...');
+  const qlConfigurationListener = await QueryServerConfigListener.createQueryServerConfigListener(
+    distributionManager
+  );
   ctx.subscriptions.push(qlConfigurationListener);
 
-  const cliServer = new CodeQLCliServer(distributionManager, logger);
+  logger.log('Initializing CodeQL cli server...');
+  const cliServer = new CodeQLCliServer(
+    distributionManager,
+    new CliConfigListener(),
+    logger
+  );
   ctx.subscriptions.push(cliServer);
 
-  const qs = new qsClient.QueryServerClient(qlConfigurationListener, cliServer, {
-    logger: queryServerLogger,
-  }, task => Window.withProgress({ title: 'CodeQL query server', location: ProgressLocation.Window }, task));
+  const statusBar = new CodeQlStatusBarHandler(cliServer, distributionConfigListener);
+  ctx.subscriptions.push(statusBar);
+
+  logger.log('Initializing query server client.');
+  const qs = new qsClient.QueryServerClient(
+    qlConfigurationListener,
+    cliServer,
+    {
+      logger: queryServerLogger,
+    },
+    (task) =>
+      Window.withProgress(
+        { title: 'CodeQL query server', location: ProgressLocation.Window },
+        task
+      )
+  );
   ctx.subscriptions.push(qs);
   await qs.startQueryServer();
 
-  const dbm = new DatabaseManager(ctx, qlConfigurationListener, logger);
+  logger.log('Initializing database manager.');
+  const dbm = new DatabaseManager(ctx, qs, cliServer, logger);
   ctx.subscriptions.push(dbm);
-  const databaseUI = new DatabaseUI(ctx, cliServer, dbm, qs);
+  logger.log('Initializing database panel.');
+  const databaseUI = new DatabaseUI(
+    dbm,
+    qs,
+    getContextStoragePath(ctx),
+    ctx.extensionPath
+  );
+  databaseUI.init();
   ctx.subscriptions.push(databaseUI);
 
+  logger.log('Initializing query history manager.');
   const queryHistoryConfigurationListener = new QueryHistoryConfigListener();
+  ctx.subscriptions.push(queryHistoryConfigurationListener);
+  const showResults = async (item: CompletedQuery) =>
+    showResultsForCompletedQuery(item, WebviewReveal.Forced);
+
   const qhm = new QueryHistoryManager(
-    ctx,
+    qs,
+    ctx.extensionPath,
     queryHistoryConfigurationListener,
-    async item => showResultsForCompletedQuery(item, WebviewReveal.Forced)
+    showResults,
+    async (from: CompletedQuery, to: CompletedQuery) =>
+      showResultsForComparison(from, to),
   );
+  ctx.subscriptions.push(qhm);
+  logger.log('Initializing results panel interface.');
   const intm = new InterfaceManager(ctx, dbm, cliServer, queryServerLogger);
   ctx.subscriptions.push(intm);
+
+  logger.log('Initializing compare panel interface.');
+  const cmpm = new CompareInterfaceManager(
+    ctx,
+    dbm,
+    cliServer,
+    queryServerLogger,
+    showResults
+  );
+  ctx.subscriptions.push(cmpm);
+
+  logger.log('Initializing source archive filesystem provider.');
   archiveFilesystemProvider.activate(ctx);
 
-  async function showResultsForCompletedQuery(query: CompletedQuery, forceReveal: WebviewReveal): Promise<void> {
+  async function showResultsForComparison(
+    from: CompletedQuery,
+    to: CompletedQuery
+  ): Promise<void> {
+    try {
+      await cmpm.showResults(from, to);
+    } catch (e) {
+      helpers.showAndLogErrorMessage(e.message);
+    }
+  }
+
+  async function showResultsForCompletedQuery(
+    query: CompletedQuery,
+    forceReveal: WebviewReveal
+  ): Promise<void> {
     await intm.showResults(query, forceReveal, false);
   }
 
-  async function compileAndRunQuery(quickEval: boolean, selectedQuery: Uri | undefined): Promise<void> {
+  async function compileAndRunQuery(
+    quickEval: boolean,
+    selectedQuery: Uri | undefined,
+    progress: ProgressCallback,
+    token: CancellationToken,
+  ): Promise<void> {
     if (qs !== undefined) {
-      try {
-        const dbItem = await databaseUI.getDatabaseItem();
-        if (dbItem === undefined) {
-          throw new Error('Can\'t run query without a selected database');
-        }
-        const info = await compileAndRunQueryAgainstDatabase(cliServer, qs, dbItem, quickEval, selectedQuery);
-        const item = qhm.addQuery(info);
-        await showResultsForCompletedQuery(item, WebviewReveal.NotForced);
-      } catch (e) {
-        if (e instanceof UserCancellationException) {
-          helpers.showAndLogWarningMessage(e.message);
-        } else if (e instanceof Error) {
-          helpers.showAndLogErrorMessage(e.message);
-        } else {
-          throw e;
-        }
+      const dbItem = await databaseUI.getDatabaseItem(progress, token);
+      if (dbItem === undefined) {
+        throw new Error('Can\'t run query without a selected database');
+      }
+      const info = await compileAndRunQueryAgainstDatabase(
+        cliServer,
+        qs,
+        dbItem,
+        quickEval,
+        selectedQuery,
+        progress,
+        token
+      );
+      const item = qhm.buildCompletedQuery(info);
+      await showResultsForCompletedQuery(item, WebviewReveal.NotForced);
+      // Note we must update the query history view after showing results as the
+      // display and sorting might depend on the number of results
+      await qhm.addCompletedQuery(item);
+    }
+  }
+
+  async function openReferencedFile(
+    selectedQuery: Uri
+  ): Promise<void> {
+    if (qs !== undefined) {
+      if (await cliServer.cliConstraints.supportsResolveQlref()) {
+        const resolved = await cliServer.resolveQlref(selectedQuery.path);
+        const uri = Uri.file(resolved.resolvedPath);
+        await window.showTextDocument(uri, { preview: false });
+      } else {
+        helpers.showAndLogErrorMessage(
+          'Jumping from a .qlref file to the .ql file it references is not '
+          + 'supported with the CLI version you are running.\n'
+          + `Please upgrade your CLI to version ${
+          CliVersionConstraint.CLI_VERSION_WITH_RESOLVE_QLREF
+          } or later to use this feature.`);
       }
     }
   }
 
   ctx.subscriptions.push(tmpDirDisposal);
 
-  const client = new LanguageClient('CodeQL Language Server', () => spawnIdeServer(qlConfigurationListener), {
-    documentSelector: [
-      { language: 'ql', scheme: 'file' },
-      { language: 'yaml', scheme: 'file', pattern: '**/qlpack.yml' }
-    ],
-    synchronize: {
-      configurationSection: 'codeQL'
+  logger.log('Initializing CodeQL language server.');
+  const client = new LanguageClient(
+    'CodeQL Language Server',
+    () => spawnIdeServer(qlConfigurationListener),
+    {
+      documentSelector: [
+        { language: 'ql', scheme: 'file' },
+        { language: 'yaml', scheme: 'file', pattern: '**/qlpack.yml' },
+      ],
+      synchronize: {
+        configurationSection: 'codeQL',
+      },
+      // Ensure that language server exceptions are logged to the same channel as its output.
+      outputChannel: ideServerLogger.outputChannel,
     },
-    // Ensure that language server exceptions are logged to the same channel as its output.
-    outputChannel: ideServerLogger.outputChannel
-  }, true);
+    true
+  );
 
-  const testExplorerExtension = extensions.getExtension<TestHub>(testExplorerExtensionId);
+  logger.log('Initializing QLTest interface.');
+  const testExplorerExtension = extensions.getExtension<TestHub>(
+    testExplorerExtensionId
+  );
   if (testExplorerExtension) {
     const testHub = testExplorerExtension.exports;
     const testAdapterFactory = new QLTestAdapterFactory(testHub, cliServer);
@@ -328,27 +533,233 @@ async function activateWithInstalledDistribution(ctx: ExtensionContext, distribu
     ctx.subscriptions.push(testUIService);
   }
 
-  ctx.subscriptions.push(commands.registerCommand('codeQL.runQuery', async (uri: Uri | undefined) => await compileAndRunQuery(false, uri)));
-  ctx.subscriptions.push(commands.registerCommand('codeQL.quickEval', async (uri: Uri | undefined) => await compileAndRunQuery(true, uri)));
-  ctx.subscriptions.push(commands.registerCommand('codeQL.quickQuery', async () => displayQuickQuery(ctx, cliServer, databaseUI)));
-  ctx.subscriptions.push(commands.registerCommand('codeQL.restartQueryServer', async () => {
-    await qs.restartQueryServer();
-    helpers.showAndLogInformationMessage('CodeQL Query Server restarted.', { outputLogger: queryServerLogger });
-  }));
-  ctx.subscriptions.push(commands.registerCommand('codeQL.downloadDatabase', () => promptFetchDatabase(dbm, getContextStoragePath(ctx))));
+  logger.log('Registering top-level command palette commands.');
+  ctx.subscriptions.push(
+    commandRunnerWithProgress(
+      'codeQL.runQuery',
+      async (
+        progress: ProgressCallback,
+        token: CancellationToken,
+        uri: Uri | undefined
+      ) => await compileAndRunQuery(false, uri, progress, token),
+      {
+        title: 'Running query',
+        cancellable: true
+      }
+    )
+  );
+  ctx.subscriptions.push(
+    commandRunnerWithProgress(
+      'codeQL.runQueries',
+      async (
+        progress: ProgressCallback,
+        token: CancellationToken,
+        _: Uri | undefined,
+        multi: Uri[]
+      ) => {
+        const maxQueryCount = MAX_QUERIES.getValue() as number;
+        const [files, dirFound] = await gatherQlFiles(multi.map(uri => uri.fsPath));
+        if (files.length > maxQueryCount) {
+          throw new Error(`You tried to run ${files.length} queries, but the maximum is ${maxQueryCount}. Try selecting fewer queries or changing the 'codeQL.runningQueries.maxQueries' setting.`);
+        }
+        // warn user and display selected files when a directory is selected because some ql
+        // files may be hidden from the user.
+        if (dirFound) {
+          const fileString = files.map(file => path.basename(file)).join(', ');
+          const res = await helpers.showBinaryChoiceDialog(
+            `You are about to run ${files.length} queries: ${fileString} Do you want to continue?`
+          );
+          if (!res) {
+            return;
+          }
+        }
+        const queryUris = files.map(path => Uri.parse(`file:${path}`, true));
 
+        // Use a wrapped progress so that messages appear with the queries remaining in it.
+        let queriesRemaining = queryUris.length;
+        function wrappedProgress(update: ProgressUpdate) {
+          const message = queriesRemaining > 1
+            ? `${queriesRemaining} remaining. ${update.message}`
+            : update.message;
+          progress({
+            ...update,
+            message
+          });
+        }
+
+        if (queryUris.length > 1) {
+          // Try to upgrade the current database before running any queries
+          // so that the user isn't confronted with multiple upgrade
+          // requests for each query to run.
+          // Only do it if running multiple queries since this check is
+          // performed on each query run anyway.
+          await databaseUI.tryUpgradeCurrentDatabase(progress, token);
+        }
+
+        wrappedProgress({
+          maxStep: queryUris.length,
+          step: queryUris.length - queriesRemaining,
+          message: ''
+        });
+
+        await Promise.all(queryUris.map(async uri =>
+          compileAndRunQuery(false, uri, wrappedProgress, token)
+            .then(() => queriesRemaining--)
+        ));
+      },
+      {
+        title: 'Running queries',
+        cancellable: true
+      })
+  );
+  ctx.subscriptions.push(
+    commandRunnerWithProgress(
+      'codeQL.quickEval',
+      async (
+        progress: ProgressCallback,
+        token: CancellationToken,
+        uri: Uri | undefined
+      ) => await compileAndRunQuery(true, uri, progress, token),
+      {
+        title: 'Running query',
+        cancellable: true
+      })
+  );
+  ctx.subscriptions.push(
+    commandRunnerWithProgress('codeQL.quickQuery', async (
+      progress: ProgressCallback,
+      token: CancellationToken
+    ) =>
+      displayQuickQuery(ctx, cliServer, databaseUI, progress, token),
+      {
+        title: 'Run Quick Query'
+      }
+    )
+  );
+  ctx.subscriptions.push(
+    commandRunner(
+      'codeQL.openReferencedFile',
+      openReferencedFile
+    )
+  );
+
+  ctx.subscriptions.push(
+    commandRunnerWithProgress('codeQL.restartQueryServer', async (
+      progress: ProgressCallback,
+      token: CancellationToken
+    ) => {
+      await qs.restartQueryServer(progress, token);
+      helpers.showAndLogInformationMessage('CodeQL Query Server restarted.', {
+        outputLogger: queryServerLogger,
+      });
+    }, {
+      title: 'Restarting Query Server'
+    })
+  );
+
+  ctx.subscriptions.push(
+    commandRunnerWithProgress('codeQL.chooseDatabaseFolder', (
+      progress: ProgressCallback,
+      token: CancellationToken
+    ) =>
+      databaseUI.handleChooseDatabaseFolder(progress, token), {
+      title: 'Choose a Database from a Folder'
+    })
+  );
+  ctx.subscriptions.push(
+    commandRunnerWithProgress('codeQL.chooseDatabaseArchive', (
+      progress: ProgressCallback,
+      token: CancellationToken
+    ) =>
+      databaseUI.handleChooseDatabaseArchive(progress, token), {
+      title: 'Choose a Database from an Archive'
+    })
+  );
+  ctx.subscriptions.push(
+    commandRunnerWithProgress('codeQL.chooseDatabaseLgtm', (
+      progress: ProgressCallback,
+      token: CancellationToken
+    ) =>
+      databaseUI.handleChooseDatabaseLgtm(progress, token),
+      {
+        title: 'Adding database from LGTM. Choose a language from the dropdown, if requested.',
+      })
+  );
+  ctx.subscriptions.push(
+    commandRunnerWithProgress('codeQL.chooseDatabaseInternet', (
+      progress: ProgressCallback,
+      token: CancellationToken
+    ) =>
+      databaseUI.handleChooseDatabaseInternet(progress, token),
+
+      {
+        title: 'Adding database from URL',
+      })
+  );
+
+  ctx.subscriptions.push(
+    commandRunner('codeQL.openDocumentation', async () =>
+      env.openExternal(Uri.parse('https://codeql.github.com/docs/'))));
+
+  ctx.subscriptions.push(
+    commandRunner('codeQL.copyVersion', async () => {
+      const text = `CodeQL extension version: ${extension?.packageJSON.version} \nCodeQL CLI version: ${await cliServer.getVersion()} \nPlatform: ${os.platform()} ${os.arch()}`;
+      env.clipboard.writeText(text);
+      helpers.showAndLogInformationMessage(text);
+    }));
+
+
+  logger.log('Starting language server.');
   ctx.subscriptions.push(client.start());
 
-  if (EXPERIMENTAL_FEATURES_SETTING.getValue()) {
-    languages.registerDefinitionProvider(
-      { scheme: archiveFilesystemProvider.zipArchiveScheme },
-      new TemplateQueryDefinitionProvider(cliServer, qs, dbm)
+  // Jump-to-definition and find-references
+  logger.log('Registering jump-to-definition handlers.');
+  languages.registerDefinitionProvider(
+    { scheme: archiveFilesystemProvider.zipArchiveScheme },
+    new TemplateQueryDefinitionProvider(cliServer, qs, dbm)
+  );
+
+  languages.registerReferenceProvider(
+    { scheme: archiveFilesystemProvider.zipArchiveScheme },
+    new TemplateQueryReferenceProvider(cliServer, qs, dbm)
+  );
+
+  const astViewer = new AstViewer();
+  const templateProvider = new TemplatePrintAstProvider(cliServer, qs, dbm);
+
+  ctx.subscriptions.push(astViewer);
+  ctx.subscriptions.push(commandRunnerWithProgress('codeQL.viewAst', async (
+    progress: ProgressCallback,
+    token: CancellationToken
+  ) => {
+    const ast = await templateProvider.provideAst(
+      progress,
+      token,
+      window.activeTextEditor?.document,
     );
-    languages.registerReferenceProvider(
-      { scheme: archiveFilesystemProvider.zipArchiveScheme },
-      new TemplateQueryReferenceProvider(cliServer, qs, dbm)
-    );
-  }
+    if (ast) {
+      astViewer.updateRoots(await ast.getRoots(), ast.db, ast.fileName);
+    }
+  }, {
+    cancellable: true,
+    title: 'Calculate AST'
+  }));
+
+  commands.executeCommand('codeQLDatabases.removeOrphanedDatabases');
+
+  logger.log('Successfully finished extension initialization.');
+
+  return {
+    ctx,
+    cliServer,
+    qs,
+    distributionManager,
+    databaseManager: dbm,
+    databaseUI,
+    dispose: () => {
+      ctx.subscriptions.forEach(d => d.dispose());
+    }
+  };
 }
 
 function getContextStoragePath(ctx: ExtensionContext) {

extensions/ql-vscode/src/helpers.ts

@@ -2,52 +2,15 @@ import * as fs from 'fs-extra';
 import * as glob from 'glob-promise';
 import * as yaml from 'js-yaml';
 import * as path from 'path';
-import { CancellationToken, ExtensionContext, ProgressOptions, window as Window, workspace } from 'vscode';
+import {
+  ExtensionContext,
+  Uri,
+  window as Window,
+  workspace,
+  env
+} from 'vscode';
 import { CodeQLCliServer } from './cli';
 import { logger } from './logging';
-import { QueryInfo } from './run-queries';
-
-export interface ProgressUpdate {
-  /**
-   * The current step
-   */
-  step: number;
-  /**
-   * The maximum step. This *should* be constant for a single job.
-   */
-  maxStep: number;
-  /**
-   * The current progress message
-   */
-  message: string;
-}
-
-export type ProgressCallback = (p: ProgressUpdate) => void;
-
-/**
- * This mediates between the kind of progress callbacks we want to
- * write (where we *set* current progress position and give
- * `maxSteps`) and the kind vscode progress api expects us to write
- * (which increment progress by a certain amount out of 100%)
- */
-export function withProgress<R>(
-  options: ProgressOptions,
-  task: (
-    progress: (p: ProgressUpdate) => void,
-    token: CancellationToken
-  ) => Thenable<R>
-): Thenable<R> {
-  let progressAchieved = 0;
-  return Window.withProgress(options,
-    (progress, token) => {
-      return task(p => {
-        const { message, step, maxStep } = p;
-        const increment = 100 * (step - progressAchieved) / maxStep;
-        progressAchieved = step;
-        progress.report({ message, increment });
-      }, token);
-    });
-}
 
 /**
  * Show an error message and log it to the console
@@ -55,15 +18,24 @@ export function withProgress<R>(
  * @param message The message to show.
  * @param options.outputLogger The output logger that will receive the message
  * @param options.items A set of items that will be rendered as actions in the message.
+ * @param options.fullMessage An alternate message that is added to the log, but not displayed
+ *                           in the popup. This is useful for adding extra detail to the logs
+ *                           that would be too noisy for the popup.
  *
  * @return A promise that resolves to the selected item or undefined when being dismissed.
  */
 export async function showAndLogErrorMessage(message: string, {
   outputLogger = logger,
-  items = [] as string[]
+  items = [] as string[],
+  fullMessage = undefined as (string | undefined)
 } = {}): Promise<string | undefined> {
-  return internalShowAndLog(message, items, outputLogger, Window.showErrorMessage);
+  return internalShowAndLog(dropLinesExceptInitial(message), items, outputLogger, Window.showErrorMessage, fullMessage);
 }
+
+function dropLinesExceptInitial(message: string, n = 2) {
+  return message.toString().split(/\r?\n/).slice(0, n).join('\n');
+}
+
 /**
  * Show a warning message and log it to the console
  *
@@ -97,10 +69,15 @@ export async function showAndLogInformationMessage(message: string, {
 
 type ShowMessageFn = (message: string, ...items: string[]) => Thenable<string | undefined>;
 
-async function internalShowAndLog(message: string, items: string[], outputLogger = logger,
-  fn: ShowMessageFn): Promise<string | undefined> {
+async function internalShowAndLog(
+  message: string,
+  items: string[],
+  outputLogger = logger,
+  fn: ShowMessageFn,
+  fullMessage?: string
+): Promise<string | undefined> {
   const label = 'Show Log';
-  outputLogger.log(message);
+  outputLogger.log(fullMessage || message);
   const result = await fn(message, label, ...items);
   if (result === label) {
     outputLogger.show();
@@ -110,15 +87,59 @@ async function internalShowAndLog(message: string, items: string[], outputLogger
 
 /**
  * Opens a modal dialog for the user to make a yes/no choice.
- * @param message The message to show.
  *
- * @return `true` if the user clicks 'Yes', `false` if the user clicks 'No' or cancels the dialog.
+ * @param message The message to show.
+ * @param modal If true (the default), show a modal dialog box, otherwise dialog is non-modal and can
+ *        be closed even if the user does not make a choice.
+ *
+ * @return
+ *  `true` if the user clicks 'Yes',
+ *  `false` if the user clicks 'No' or cancels the dialog,
+ *  `undefined` if the dialog is closed without the user making a choice.
  */
-export async function showBinaryChoiceDialog(message: string): Promise<boolean> {
+export async function showBinaryChoiceDialog(message: string, modal = true): Promise<boolean | undefined> {
   const yesItem = { title: 'Yes', isCloseAffordance: false };
-  const noItem = { title: 'No', isCloseAffordance: true }
-  const chosenItem = await Window.showInformationMessage(message, { modal: true }, yesItem, noItem);
-  return chosenItem === yesItem;
+  const noItem = { title: 'No', isCloseAffordance: true };
+  const chosenItem = await Window.showInformationMessage(message, { modal }, yesItem, noItem);
+  if (!chosenItem) {
+    return undefined;
+  }
+  return chosenItem?.title === yesItem.title;
+}
+
+/**
+ * Opens a modal dialog for the user to make a yes/no choice.
+ *
+ * @param message The message to show.
+ * @param modal If true (the default), show a modal dialog box, otherwise dialog is non-modal and can
+ *        be closed even if the user does not make a choice.
+ *
+ * @return
+ *  `true` if the user clicks 'Yes',
+ *  `false` if the user clicks 'No' or cancels the dialog,
+ *  `undefined` if the dialog is closed without the user making a choice.
+ */
+export async function showBinaryChoiceWithUrlDialog(message: string, url: string): Promise<boolean | undefined> {
+  const urlItem = { title: 'More Information', isCloseAffordance: false };
+  const yesItem = { title: 'Yes', isCloseAffordance: false };
+  const noItem = { title: 'No', isCloseAffordance: true };
+  let chosenItem;
+
+  // Keep the dialog open as long as the user is clicking the 'more information' option.
+  // To prevent an infinite loop, if the user clicks 'more information' 5 times, close the dialog and return cancelled
+  let count = 0;
+  do {
+    chosenItem = await Window.showInformationMessage(message, { modal: true }, urlItem, yesItem, noItem);
+    if (chosenItem === urlItem) {
+      await env.openExternal(Uri.parse(url, true));
+    }
+    count++;
+  } while (chosenItem === urlItem && count < 5);
+
+  if (!chosenItem || chosenItem.title === urlItem.title) {
+    return undefined;
+  }
+  return chosenItem.title === yesItem.title;
 }
 
 /**
@@ -139,30 +160,12 @@ export function getOnDiskWorkspaceFolders() {
   const workspaceFolders = workspace.workspaceFolders || [];
   const diskWorkspaceFolders: string[] = [];
   for (const workspaceFolder of workspaceFolders) {
-    if (workspaceFolder.uri.scheme === "file")
-      diskWorkspaceFolders.push(workspaceFolder.uri.fsPath)
+    if (workspaceFolder.uri.scheme === 'file')
+      diskWorkspaceFolders.push(workspaceFolder.uri.fsPath);
   }
   return diskWorkspaceFolders;
 }
 
-/**
- * Gets a human-readable name for an evaluated query.
- * Uses metadata if it exists, and defaults to the query file name.
- */
-export function getQueryName(query: QueryInfo) {
-  // Queries run through quick evaluation are not usually the entire query file.
-  // Label them differently and include the line numbers.
-  if (query.quickEvalPosition !== undefined) {
-    const { line, endLine, fileName } = query.quickEvalPosition;
-    const lineInfo = line === endLine ? `${line}` : `${line}-${endLine}`;
-    return `Quick evaluation of ${path.basename(fileName)}:${lineInfo}`;
-  } else if (query.metadata && query.metadata.name) {
-    return query.metadata.name;
-  } else {
-    return path.basename(query.program.queryPath);
-  }
-}
-
 /**
  * Provides a utility method to invoke a function only if a minimum time interval has elapsed since
  * the last invocation of that function.
@@ -213,7 +216,7 @@ export class InvocationRateLimiter<T> {
   private readonly _func: () => Promise<T>;
   private readonly _funcIdentifier: string;
 
-  private static readonly _invocationRateLimiterPrefix = "invocationRateLimiter_lastInvocationDate_";
+  private static readonly _invocationRateLimiterPrefix = 'invocationRateLimiter_lastInvocationDate_';
 }
 
 export enum InvocationRateLimiterResultKind {
@@ -251,12 +254,6 @@ function createRateLimitedResult(): RateLimitedResult {
   };
 }
 
-
-export type DatasetFolderInfo = {
-  dbscheme: string;
-  qlpack: string;
-}
-
 export async function getQlPackForDbscheme(cliServer: CodeQLCliServer, dbschemePath: string): Promise<string> {
   const qlpacks = await cliServer.resolveQlpacks(getOnDiskWorkspaceFolders());
   const packs: { packDir: string | undefined; packName: string }[] =
@@ -271,11 +268,11 @@ export async function getQlPackForDbscheme(cliServer: CodeQLCliServer, dbschemeP
       return {
         packName,
         packDir: dirs[0]
-      }
+      };
     });
   for (const { packDir, packName } of packs) {
     if (packDir !== undefined) {
-      const qlpack = yaml.safeLoad(await fs.readFile(path.join(packDir, 'qlpack.yml'), 'utf8'));
+      const qlpack = yaml.safeLoad(await fs.readFile(path.join(packDir, 'qlpack.yml'), 'utf8')) as { dbscheme: string };
       if (qlpack.dbscheme !== undefined && path.basename(qlpack.dbscheme) === path.basename(dbschemePath)) {
         return packName;
       }
@@ -284,8 +281,8 @@ export async function getQlPackForDbscheme(cliServer: CodeQLCliServer, dbschemeP
   throw new Error(`Could not find qlpack file for dbscheme ${dbschemePath}`);
 }
 
-export async function resolveDatasetFolder(cliServer: CodeQLCliServer, datasetFolder: string): Promise<DatasetFolderInfo> {
-  const dbschemes = await glob(path.join(datasetFolder, '*.dbscheme'))
+export async function getPrimaryDbscheme(datasetFolder: string): Promise<string> {
+  const dbschemes = await glob(path.join(datasetFolder, '*.dbscheme'));
 
   if (dbschemes.length < 1) {
     throw new Error(`Can't find dbscheme for current database in ${datasetFolder}`);
@@ -293,36 +290,35 @@ export async function resolveDatasetFolder(cliServer: CodeQLCliServer, datasetFo
 
   dbschemes.sort();
   const dbscheme = dbschemes[0];
+
   if (dbschemes.length > 1) {
     Window.showErrorMessage(`Found multiple dbschemes in ${datasetFolder} during quick query; arbitrarily choosing the first, ${dbscheme}, to decide what library to use.`);
   }
-
-  const qlpack = await getQlPackForDbscheme(cliServer, dbscheme);
-  return { dbscheme, qlpack };
+  return dbscheme;
 }
 
 /**
  * A cached mapping from strings to value of type U.
  */
 export class CachedOperation<U> {
-  private readonly operation: (t: string) => Promise<U>;
+  private readonly operation: (t: string, ...args: any[]) => Promise<U>;
   private readonly cached: Map<string, U>;
   private readonly lru: string[];
   private readonly inProgressCallbacks: Map<string, [(u: U) => void, (reason?: any) => void][]>;
 
-  constructor(operation: (t: string) => Promise<U>, private cacheSize = 100) {
+  constructor(operation: (t: string, ...args: any[]) => Promise<U>, private cacheSize = 100) {
     this.operation = operation;
     this.lru = [];
     this.inProgressCallbacks = new Map<string, [(u: U) => void, (reason?: any) => void][]>();
     this.cached = new Map<string, U>();
   }
 
-  async get(t: string): Promise<U> {
+  async get(t: string, ...args: any[]): Promise<U> {
     // Try and retrieve from the cache
     const fromCache = this.cached.get(t);
     if (fromCache !== undefined) {
       // Move to end of lru list
-      this.lru.push(this.lru.splice(this.lru.findIndex(v => v === t), 1)[0])
+      this.lru.push(this.lru.splice(this.lru.findIndex(v => v === t), 1)[0]);
       return fromCache;
     }
     // Otherwise check if in progress
@@ -338,7 +334,7 @@ export class CachedOperation<U> {
     const callbacks: [(u: U) => void, (reason?: any) => void][] = [];
     this.inProgressCallbacks.set(t, callbacks);
     try {
-      const result = await this.operation(t);
+      const result = await this.operation(t, ...args);
       callbacks.forEach(f => f[0](result));
       this.inProgressCallbacks.delete(t);
       if (this.lru.length > this.cacheSize) {
@@ -357,3 +353,74 @@ export class CachedOperation<U> {
     }
   }
 }
+
+
+
+/**
+ * The following functions al heuristically determine metadata about databases.
+ */
+
+/**
+ * Note that this heuristic is only being used for backwards compatibility with
+ * CLI versions before the langauge name was introduced to dbInfo. Features
+ * that do not require backwards compatibility should call
+ * `cli.CodeQLCliServer.resolveDatabase` and use the first entry in the
+ * `languages` property.
+ *
+ * @see cli.CliVersionConstraint.supportsLanguageName
+ * @see cli.CodeQLCliServer.resolveDatabase
+ */
+const dbSchemeToLanguage = {
+  'semmlecode.javascript.dbscheme': 'javascript',
+  'semmlecode.cpp.dbscheme': 'cpp',
+  'semmlecode.dbscheme': 'java',
+  'semmlecode.python.dbscheme': 'python',
+  'semmlecode.csharp.dbscheme': 'csharp',
+  'go.dbscheme': 'go'
+};
+
+/**
+ * Returns the initial contents for an empty query, based on the language of the selected
+ * databse.
+ *
+ * First try to use the given language name. If that doesn't exist, try to infer it based on
+ * dbscheme. Otherwise return no import statement.
+ *
+ * @param language the database language or empty string if unknown
+ * @param dbscheme path to the dbscheme file
+ *
+ * @returns an import and empty select statement appropriate for the selected language
+ */
+export function getInitialQueryContents(language: string, dbscheme: string) {
+  if (!language) {
+    const dbschemeBase = path.basename(dbscheme) as keyof typeof dbSchemeToLanguage;
+    language = dbSchemeToLanguage[dbschemeBase];
+  }
+
+  return language
+    ? `import ${language}\n\nselect ""`
+    : 'select ""';
+}
+
+/**
+ * Heuristically determines if the directory passed in corresponds
+ * to a database root.
+ *
+ * @param maybeRoot
+ */
+export async function isLikelyDatabaseRoot(maybeRoot: string) {
+  const [a, b, c] = (await Promise.all([
+    // databases can have either .dbinfo or codeql-database.yml.
+    fs.pathExists(path.join(maybeRoot, '.dbinfo')),
+    fs.pathExists(path.join(maybeRoot, 'codeql-database.yml')),
+
+    // they *must* have a db-{language} folder
+    glob('db-*/', { cwd: maybeRoot })
+  ]));
+
+  return !!((a || b) && c);
+}
+
+export function isLikelyDbLanguageFolder(dbPath: string) {
+  return !!path.basename(dbPath).startsWith('db-');
+}