Use VSCode file system watcher

Author: pokey

packages/common/src/ide/types/FileSystem.types.ts

@@ -9,5 +9,5 @@ export interface FileSystem {
    * @param onDidChange A function to call on changes
    * @returns A disposable to cancel the watcher
    */
-  watchDir(path: string, onDidChange: PathChangeListener): Disposable;
+  watch(path: string, onDidChange: PathChangeListener): Disposable;
 }

packages/cursorless-engine/src/ScopeVisualizer/ScopeInfoProvider.ts

@@ -43,11 +43,7 @@ export class ScopeInfoProvider {
 
   private constructor(fileSystem: FileSystem) {
     this.disposables.push(
-      // TODO: Watch just the path we care about
-      fileSystem.watchDir(
-        path.join(homedir(), ".cursorless"),
-        this.debouncer.run,
-      ),
+      fileSystem.watch(spokenFormsPath, this.debouncer.run),
       this.debouncer,
     );
 

packages/cursorless-engine/src/languages/LanguageDefinitions.ts

@@ -57,7 +57,7 @@ export class LanguageDefinitions {
 
     if (ide().runMode === "development") {
       this.disposables.push(
-        fileSystem.watchDir(this.queryDir, () => {
+        fileSystem.watch(this.queryDir, () => {
           this.languageDefinitions.clear();
           this.notifier.notifyListeners();
         }),

packages/cursorless-vscode/src/ide/vscode/VscodeFileSystem.ts

@@ -1,52 +1,19 @@
 import {
   Disposable,
   FileSystem,
-  PathChangeListener,
-  walkFiles,
+  PathChangeListener
 } from "@cursorless/common";
-import { stat } from "fs/promises";
-import { max } from "lodash";
+import { RelativePattern, workspace } from "vscode";
 
 export class VscodeFileSystem implements FileSystem {
-  watchDir(path: string, onDidChange: PathChangeListener): Disposable {
-    // Just poll for now; we can take advantage of VSCode's sophisticated
-    // watcher later. Note that we would need to do a version check, as VSCode
-    // file watcher is only available in more recent versions of VSCode.
-    return new PollingFileSystemWatcher(path, onDidChange);
+  watch(path: string, onDidChange: PathChangeListener): Disposable {
+    // TODO: What happens on VSCode before 1.64?
+    // FIXME: Support globs?
+    const watcher = workspace.createFileSystemWatcher(new RelativePattern(path, "**"));
+    watcher.onDidChange(onDidChange);
+    watcher.onDidCreate(onDidChange);
+    watcher.onDidDelete(onDidChange);
+    return watcher;
   }
 }
 
-const CHECK_INTERVAL_MS = 1000;
-
-class PollingFileSystemWatcher implements Disposable {
-  private maxMtimeMs: number = -1;
-  private timer: NodeJS.Timer;
-
-  constructor(
-    private readonly path: string,
-    private readonly onDidChange: PathChangeListener,
-  ) {
-    this.checkForChanges = this.checkForChanges.bind(this);
-    this.timer = setInterval(this.checkForChanges, CHECK_INTERVAL_MS);
-  }
-
-  private async checkForChanges() {
-    const paths = await walkFiles(this.path);
-
-    const maxMtime =
-      max(
-        (await Promise.all(paths.map((file) => stat(file)))).map(
-          (stat) => stat.mtimeMs,
-        ),
-      ) ?? 0;
-
-    if (maxMtime > this.maxMtimeMs) {
-      this.maxMtimeMs = maxMtime;
-      this.onDidChange();
-    }
-  }
-
-  dispose() {
-    clearInterval(this.timer);
-  }
-}