Add commands for path navigation

extensions/ql-vscode/package.json

@@ -170,6 +170,14 @@
       {
         "command": "codeQLQueryHistory.itemClicked",
         "title": "Query History Item"
+      },
+      {
+        "command": "codeQLQueryResults.nextPathStep",
+        "title": "CodeQL: Show Next Step on Path"
+      },
+      {
+        "command": "codeQLQueryResults.previousPathStep",
+        "title": "CodeQL: Show Previous Step on Path"
       }
     ],
     "menus": {

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

@@ -65,7 +65,15 @@ export interface SetStateMsg {
   shouldKeepOldResultsWhileRendering: boolean;
 };
 
-export type IntoResultsViewMsg = ResultsUpdatingMsg | SetStateMsg;
+/** Advance to the next or previous path no in the path viewer */
+export interface NavigatePathMsg {
+  t: 'navigatePath',
+
+  /** 1 for next, -1 for previous */
+  direction: number;
+}
+
+export type IntoResultsViewMsg = ResultsUpdatingMsg | SetStateMsg | NavigatePathMsg;
 
 export type FromResultsViewMsg = ViewSourceFileMsg | ToggleDiagnostics | ChangeSortMsg | ResultViewLoaded;
 

extensions/ql-vscode/src/interface.ts

@@ -99,6 +99,12 @@ export class InterfaceManager extends DisposableObject {
     super();
     this.push(this._diagnosticCollection);
     this.push(vscode.window.onDidChangeTextEditorSelection(this.handleSelectionChange.bind(this)));
+    this.push(vscode.commands.registerCommand('codeQLQueryResults.nextPathStep', this.navigatePathStep.bind(this, 1)));
+    this.push(vscode.commands.registerCommand('codeQLQueryResults.previousPathStep', this.navigatePathStep.bind(this, -1)));
+  }
+
+  navigatePathStep(direction: number) {
+    this.postMessage({ t: "navigatePath", direction });
   }
 
   // Returns the webview panel, creating it if it doesn't already

extensions/ql-vscode/src/view/alert-table.tsx

@@ -4,8 +4,8 @@ import * as Sarif from 'sarif';
 import * as Keys from '../result-keys';
 import { LocationStyle, ResolvableLocationValue } from 'semmle-bqrs';
 import * as octicons from './octicons';
-import { className, renderLocation, ResultTableProps, zebraStripe, selectableZebraStripe } from './result-table-utils';
-import { PathTableResultSet } from './results';
+import { className, renderLocation, ResultTableProps, zebraStripe, selectableZebraStripe, jumpToLocation } from './result-table-utils';
+import { PathTableResultSet, onNavigation, NavigationEvent } from './results';
 
 export type PathTableProps = ResultTableProps & { resultSet: PathTableResultSet };
 export interface PathTableState {
@@ -75,6 +75,7 @@ export class PathTable extends React.Component<PathTableProps, PathTableState> {
   constructor(props: PathTableProps) {
     super(props);
     this.state = { expanded: {}, selectedPathNode: undefined };
+    this.handleNavigationEvent = this.handleNavigationEvent.bind(this);
   }
 
   /**
@@ -290,6 +291,37 @@ export class PathTable extends React.Component<PathTableProps, PathTableState> {
       <tbody>{rows}</tbody>
     </table>;
   }
+
+  private handleNavigationEvent(event: NavigationEvent) {
+    this.setState(prevState => {
+      let { selectedPathNode } = prevState;
+      if (selectedPathNode === undefined) return prevState;
+
+      let path = Keys.getPath(this.props.resultSet.sarif, selectedPathNode);
+      if (path === undefined) return prevState;
+
+      let nextIndex = selectedPathNode.pathNodeIndex + event.direction;
+      if (nextIndex < 0 || nextIndex >= path.locations.length) return prevState;
+
+      let sarifLoc = path.locations[nextIndex].location;
+      if (sarifLoc === undefined) return prevState;
+
+      let loc = parseSarifLocation(sarifLoc, this.props.resultSet.sourceLocationPrefix);
+      if (loc.t === 'NoLocation') return prevState;
+
+      jumpToLocation(loc, this.props.databaseUri);
+      let newSelection = { ...selectedPathNode, pathNodeIndex: nextIndex };
+      return { ...prevState, selectedPathNode: newSelection };
+    });
+  }
+
+  componentDidMount() {
+    onNavigation.addListener(this.handleNavigationEvent);
+  }
+
+  componentWillUnmount() {
+    onNavigation.removeListener(this.handleNavigationEvent);
+  }
 }
 
 function parseSarifLocation(loc: Sarif.Location, sourceLocationPrefix: string): ParsedSarifLocation {

extensions/ql-vscode/src/view/event-handler-list.ts

@@ -0,0 +1,25 @@
+export type EventHandler<T> = (event: T) => void;
+
+/**
+ * A set of listeners for events of type `T`.
+ */
+export class EventHandlers<T> {
+    private handlers: EventHandler<T>[] = [];
+
+    public addListener(handler: EventHandler<T>) {
+        this.handlers.push(handler);
+    }
+
+    public removeListener(handler: EventHandler<T>) {
+        let index = this.handlers.indexOf(handler);
+        if (index !== -1) {
+            this.handlers.splice(index, 1);
+        }
+    }
+
+    public fire(event: T) {
+        for (let handler of this.handlers) {
+            handler(event);
+        }
+    }
+}

extensions/ql-vscode/src/view/result-table-utils.tsx

@@ -24,17 +24,21 @@ export function jumpToLocationHandler(
   callback?: () => void
 ): (e: React.MouseEvent) => void {
   return (e) => {
-    vscode.postMessage({
-      t: 'viewSourceFile',
-      loc,
-      databaseUri
-    });
+    jumpToLocation(loc, databaseUri);
     e.preventDefault();
     e.stopPropagation();
     if (callback) callback();
   };
 }
 
+export function jumpToLocation(loc: ResolvableLocationValue, databaseUri: string) {
+  vscode.postMessage({
+    t: 'viewSourceFile',
+    loc,
+    databaseUri
+  });
+}
+
 /**
  * Render a location as a link which when clicked displays the original location.
  */

extensions/ql-vscode/src/view/results.tsx

@@ -3,8 +3,9 @@ import * as Rdom from 'react-dom';
 import * as bqrs from 'semmle-bqrs';
 import { ElementBase, LocationValue, PrimitiveColumnValue, PrimitiveTypeKind, ResultSetSchema, tryGetResolvableLocation } from 'semmle-bqrs';
 import { assertNever } from '../helpers-pure';
-import { DatabaseInfo, FromResultsViewMsg, Interpretation, IntoResultsViewMsg, SortedResultSetInfo, SortState } from '../interface-types';
+import { DatabaseInfo, FromResultsViewMsg, Interpretation, IntoResultsViewMsg, SortedResultSetInfo, SortState, NavigatePathMsg } from '../interface-types';
 import { ResultTables } from './result-tables';
+import { EventHandlers as EventHandlerList } from './event-handler-list';
 
 /**
  * results.tsx
@@ -156,6 +157,13 @@ interface ResultsViewState {
   isExpectingResultsUpdate: boolean;
 }
 
+export type NavigationEvent = NavigatePathMsg;
+
+/**
+ * Event handlers to be notified of navigation events coming from outside the webview.
+ */
+export const onNavigation = new EventHandlerList<NavigationEvent>();
+
 /**
  * A minimal state container for displaying results.
  */
@@ -192,6 +200,9 @@ class App extends React.Component<{}, ResultsViewState> {
           isExpectingResultsUpdate: true
         });
         break;
+      case 'navigatePath':
+        onNavigation.fire(msg);
+        break;
       default:
         assertNever(msg);
     }