expose EventEmitter in our API, fixes #2359

extensions/vscode-api-tests/src/workspace.test.ts

@@ -6,7 +6,7 @@
 'use strict';
 
 import * as assert from 'assert';
-import {workspace, TextDocument, window, Position, Uri, CancellationTokenSource, Disposable} from 'vscode';
+import {workspace, TextDocument, window, Position, Uri, EventEmitter, CancellationTokenSource, Disposable} from 'vscode';
 import {createRandomFile, deleteFile, cleanUp, pathEquals} from './utils';
 import {join, basename} from 'path';
 import * as fs from 'fs';
@@ -286,26 +286,16 @@ suite('workspace-namespace', () => {
 	test('registerTextDocumentContentProvider, change event', function() {
 
 		let callCount = 0;
-		let listeners: Function[] = [];
+		let emitter = new EventEmitter<Uri>();
+
 		let registration = workspace.registerTextDocumentContentProvider('foo', {
-			onDidChange(callback, thisArg, disposables) {
+			onDidChange: emitter.event,
-				let actual = thisArg ? callback.bind(thisArg) : callback;
-				listeners.push(actual);
-				let subscription = new Disposable(() => {
-					const idx = listeners.indexOf(actual);
-					listeners.splice(idx, 1);
-				});
-				if (Array.isArray(disposables)) {
-					disposables.push(subscription);
-				}
-				return subscription;
-			},
 			provideTextDocumentContent(uri) {
 				return 'call' + (callCount++);
 			}
 		});
 
-		const uri = Uri.parse('foo://testing/path2');
+		const uri = Uri.parse('foo://testing/path3');
 
 		return workspace.openTextDocument(uri).then(doc => {
 
@@ -320,7 +310,7 @@ suite('workspace-namespace', () => {
 					resolve();
 				});
 
-				listeners.forEach(l => l(doc.uri));
+				emitter.fire(doc.uri);
 
 				registration.dispose();
 			});

src/vs/vscode.d.ts

@@ -999,6 +999,35 @@ declare namespace vscode {
 		(listener: (e: T) => any, thisArgs?: any, disposables?: Disposable[]): Disposable;
 	}
 
+	/**
+	 * An event emitter can be used to create and manage an [event](#Event) for others
+	 * to subscribe to. One emitter always owns one event.
+	 *
+	 * Use this class if you want to provide event from within your extension, for instance
+	 * inside a [TextDocumentContentProvider](#TextDocumentContentProvider)mor when providing
+	 * API to other extensions.
+	 */
+	export class EventEmitter<T> {
+
+		/**
+		 * The event listeners can subscribe to.
+		 */
+		event: Event<T>;
+
+		/**
+		 * Notify all subscribers of the [event](EventEmitter#event). Failure
+		 * of one or more listener will not fail this function call.
+		 *
+		 * @param data The event object.
+		 */
+		fire(data?: T): void;
+
+		/**
+		 * Dispose this object and free resources.
+		 */
+		dispose(): void;
+	}
+
 	/**
 	 * A file system watcher notifies about changes to files and folders
 	 * on disk.

src/vs/workbench/api/node/extHost.api.impl.ts

@@ -4,6 +4,7 @@
  *--------------------------------------------------------------------------------------------*/
 'use strict';
 
+import {Emitter} from 'vs/base/common/event';
 import {IBracketElectricCharacterContribution} from 'vs/editor/common/modes/supports';
 import {score} from 'vs/editor/common/modes/languageSelector';
 import {Remotable, IThreadService} from 'vs/platform/thread/common/thread';
@@ -71,6 +72,7 @@ export class ExtHostAPIImplementation {
 	Range: typeof vscode.Range;
 	Selection: typeof vscode.Selection;
 	CancellationTokenSource: typeof vscode.CancellationTokenSource;
+	EventEmitter: typeof vscode.EventEmitter;
 	Hover: typeof vscode.Hover;
 	DocumentHighlightKind: typeof vscode.DocumentHighlightKind;
 	DocumentHighlight: typeof vscode.DocumentHighlight;
@@ -106,7 +108,8 @@ export class ExtHostAPIImplementation {
 		this.Uri = URI;
 		this.Location = extHostTypes.Location;
 		this.Diagnostic = <any> extHostTypes.Diagnostic;
-		this.DiagnosticSeverity = <any> extHostTypes.DiagnosticSeverity;
+		this.DiagnosticSeverity = <any>extHostTypes.DiagnosticSeverity;
+		this.EventEmitter = Emitter;
 		this.Disposable = extHostTypes.Disposable;
 		this.TextEdit = extHostTypes.TextEdit;
 		this.WorkspaceEdit = extHostTypes.WorkspaceEdit;