First cut of an ext host onWillSaveTextDocumentEvent

src/vs/workbench/api/node/extHostDocumentSaveParticipant.ts

@@ -0,0 +1,68 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+'use strict';
+
+import Event from 'vs/base/common/event';
+import CallbackList from 'vs/base/common/callbackList';
+import URI from 'vs/base/common/uri';
+import {sequence} from 'vs/base/common/async';
+import {illegalState} from 'vs/base/common/errors';
+import {TPromise} from 'vs/base/common/winjs.base';
+import {ExtHostDocuments} from 'vs/workbench/api/node/extHostDocuments';
+
+export interface TextDocumentWillSaveEvent {
+	waitUntil(t: Thenable<any>): void;
+}
+
+export class ExtHostDocumentSaveParticipant {
+
+	private _callbacks = new CallbackList();
+	private _documents: ExtHostDocuments;
+
+	constructor(documents: ExtHostDocuments) {
+		this._documents = documents;
+	}
+
+	dispose(): void {
+		this._callbacks.dispose();
+	}
+
+	get onWillSaveTextDocumentEvent(): Event<TextDocumentWillSaveEvent> {
+		return (listener, thisArg, disposables) => {
+			this._callbacks.add(listener, thisArg);
+			const result = { dispose: () => this._callbacks.remove(listener, thisArg) };
+			if (Array.isArray(disposables)) {
+				disposables.push(result);
+			}
+			return result;
+		};
+	}
+
+	$participateInSave(resource: URI): TPromise<any> {
+		const entries = this._callbacks.entries();
+
+		return sequence(entries.map(([fn, thisArg]) => {
+			return () => {
+				const document = this._documents.getDocumentData(resource).document;
+				return this._deliverEventAsync(fn, thisArg, document);
+			};
+		}));
+	}
+
+	private _deliverEventAsync(listener: Function, thisArg: any, document: vscode.TextDocument): TPromise<any> {
+		const promises: TPromise<any>[] = [];
+		const event = {
+			waitUntil(p: Thenable<any>) {
+				promises.push(TPromise.wrap(p));
+			}
+		};
+		try {
+			listener.apply(thisArg, [event]);
+		} finally {
+			event.waitUntil = () => { throw illegalState(); };
+			return TPromise.join(promises).then(() => void 0, err => void 0 /* ignore */);
+		}
+	}
+}