Try to request workspace content caching on commit (microsoft#185920)

For microsoft#175972

Here's what believe is happening:

- Workspace opens. We download the archive for the current commit
- User makes a commit
- The commit has now changed, which invalidates the archive. However TS doesn't know this (all the uris seem to stay the same). This means that we silently start going to the network again on file system operations

To fix this, we're going to try re-requesting the archive when a file system change event is fired for the workspace root. This should happen when a commit is made

Author: mjbvz

extensions/typescript-language-features/src/extension.browser.ts

@@ -23,6 +23,7 @@ import { Logger } from './logging/logger';
 import { getPackageInfo } from './utils/packageInfo';
 import { isWebAndHasSharedArrayBuffers } from './utils/platform';
 import { PluginManager } from './tsServer/plugins';
+import { Disposable } from './utils/dispose';
 
 class StaticVersionProvider implements ITypeScriptVersionProvider {
 
@@ -96,13 +97,13 @@ export async function activate(context: vscode.ExtensionContext): Promise<Api> {
 	});
 
 	context.subscriptions.push(lazilyActivateClient(lazyClientHost, pluginManager, activeJsTsEditorTracker, async () => {
-		await preload(logger);
+		await startPreloadWorkspaceContentsIfNeeded(context, logger);
 	}));
 
 	return getExtensionApi(onCompletionAccepted.event, pluginManager);
 }
 
-async function preload(logger: Logger): Promise<void> {
+async function startPreloadWorkspaceContentsIfNeeded(context: vscode.ExtensionContext, logger: Logger): Promise<void> {
 	if (!isWebAndHasSharedArrayBuffers()) {
 		return;
 	}
@@ -113,15 +114,46 @@ async function preload(logger: Logger): Promise<void> {
 		return;
 	}
 
-	try {
-		const remoteHubApi = await RemoteRepositories.getApi();
-		if (await remoteHubApi.loadWorkspaceContents?.(workspaceUri)) {
-			logger.info(`Successfully loaded workspace content for repository ${workspaceUri.toString()}`);
-		} else {
-			logger.info(`Failed to load workspace content for repository ${workspaceUri.toString()}`);
+	const loader = new RemoteWorkspaceContentsPreloader(workspaceUri, logger);
+	context.subscriptions.push(loader);
+	return loader.triggerPreload();
+}
+
+class RemoteWorkspaceContentsPreloader extends Disposable {
+
+	private _preload: Promise<void> | undefined;
+
+	constructor(
+		private readonly workspaceUri: vscode.Uri,
+		private readonly logger: Logger,
+	) {
+		super();
+
+		const fsWatcher = this._register(vscode.workspace.createFileSystemWatcher(new vscode.RelativePattern(workspaceUri, '*')));
+		this._register(fsWatcher.onDidChange(uri => {
+			if (uri.toString() === workspaceUri.toString()) {
+				this._preload = undefined;
+				this.triggerPreload();
+			}
+		}));
+	}
+
+	async triggerPreload() {
+		this._preload ??= this.doPreload();
+		return this._preload;
+	}
+
+	private async doPreload(): Promise<void> {
+		try {
+			const remoteHubApi = await RemoteRepositories.getApi();
+			if (await remoteHubApi.loadWorkspaceContents?.(this.workspaceUri)) {
+				this.logger.info(`Successfully loaded workspace content for repository ${this.workspaceUri.toString()}`);
+			} else {
+				this.logger.info(`Failed to load workspace content for repository ${this.workspaceUri.toString()}`);
+			}
+		} catch (error) {
+			this.logger.info(`Loading workspace content for repository ${this.workspaceUri.toString()} failed: ${error instanceof Error ? error.toString() : 'Unknown reason'}`);
+			console.error(error);
 		}
-	} catch (error) {
-		logger.info(`Loading workspace content for repository ${workspaceUri.toString()} failed: ${error instanceof Error ? error.toString() : 'Unknown reason'}`);
-		console.error(error);
 	}
 }