Fix ast view and command registration

Two small bugs:

1. The AST view command was viewing the wrong ast when the command was
   selected from the context menu. It was always selecting the active
   editor instead of the item selected in the file menu.
2. The `codeql.showLogs` command was not being registered properly.
   With this change, there is uniform error handling, telemetry,
   and disposal.

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

@@ -10,6 +10,7 @@ import {
   TextDocument,
   Uri
 } from 'vscode';
+import * as path from 'path';
 
 import { decodeSourceArchiveUri, encodeArchiveBasePath, zipArchiveScheme } from '../archive-filesystem-provider';
 import { CodeQLCliServer } from '../cli';
@@ -142,19 +143,19 @@ export class TemplatePrintAstProvider {
   async provideAst(
     progress: ProgressCallback,
     token: CancellationToken,
-    document?: TextDocument
+    fileUri?: Uri
   ): Promise<AstBuilder | undefined> {
-    if (!document) {
+    if (!fileUri) {
       throw new Error('Cannot view the AST. Please select a valid source file inside a CodeQL database.');
     }
     const { query, dbUri } = this.shouldCache()
-      ? await this.cache.get(document.uri.toString(), progress, token)
-      : await this.getAst(document.uri.toString(), progress, token);
+      ? await this.cache.get(fileUri.toString(), progress, token)
+      : await this.getAst(fileUri.toString(), progress, token);
 
     return new AstBuilder(
       query, this.cli,
       this.dbm.findDatabaseItem(dbUri)!,
-      document.fileName
+      path.basename(fileUri.fsPath),
     );
   }
 

extensions/ql-vscode/src/extension.ts

@@ -974,9 +974,11 @@ async function activateWithInstalledDistribution(
       }
     ));
 
-  commands.registerCommand('codeQL.showLogs', () => {
-    logger.show();
-  });
+  ctx.subscriptions.push(
+    commandRunner('codeQL.showLogs', async () => {
+      logger.show();
+    })
+  );
 
   void logger.log('Starting language server.');
   ctx.subscriptions.push(client.start());
@@ -999,12 +1001,14 @@ async function activateWithInstalledDistribution(
   ctx.subscriptions.push(astViewer);
   ctx.subscriptions.push(commandRunnerWithProgress('codeQL.viewAst', async (
     progress: ProgressCallback,
-    token: CancellationToken
+    token: CancellationToken,
+    selectedFile: Uri,
   ) => {
+
     const ast = await templateProvider.provideAst(
       progress,
       token,
-      window.activeTextEditor?.document,
+      selectedFile ?? window.activeTextEditor?.document.uri,
     );
     if (ast) {
       astViewer.updateRoots(await ast.getRoots(), ast.db, ast.fileName);