From 6ffa7d5887e60244169ef9699842ff276216be10 Mon Sep 17 00:00:00 2001
From: Johannes Rieken <johannes.rieken@gmail.com>
Date: Wed, 12 Feb 2020 11:09:46 +0100
Subject: [PATCH] CancellationToken#onCancellationRequested is a once-event by
 definition, helps with #81574

---
 src/vs/base/common/cancellation.ts                           | 5 ++++-
 src/vs/base/node/zip.ts                                      | 5 ++---
 src/vs/monaco.d.ts                                           | 5 ++++-
 .../services/remote/common/remoteAgentFileSystemChannel.ts   | 4 ++--
 4 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/src/vs/base/common/cancellation.ts b/src/vs/base/common/cancellation.ts
index 3685d4ded0a55..75b615de669bf 100644
--- a/src/vs/base/common/cancellation.ts
+++ b/src/vs/base/common/cancellation.ts
@@ -14,7 +14,10 @@ export interface CancellationToken {
 	readonly isCancellationRequested: boolean;
 
 	/**
-	 * An event which fires when cancellation is requested.
+	 * An event which fires when cancellation is requested. This event
+	 * only ever fires `once` as cancellation can only happen once. Listeners
+	 * that are registered after cancellation will be called (next event loop run),
+	 * but also only once.
 	 *
 	 * @event
 	 */
diff --git a/src/vs/base/node/zip.ts b/src/vs/base/node/zip.ts
index 93ebb6ad60756..8047aa275f75c 100644
--- a/src/vs/base/node/zip.ts
+++ b/src/vs/base/node/zip.ts
@@ -12,7 +12,6 @@ import { mkdirp, rimraf } from 'vs/base/node/pfs';
 import { open as _openZip, Entry, ZipFile } from 'yauzl';
 import * as yazl from 'yazl';
 import { CancellationToken } from 'vs/base/common/cancellation';
-import { Event } from 'vs/base/common/event';
 
 export interface IExtractOptions {
 	overwrite?: boolean;
@@ -80,7 +79,7 @@ function extractEntry(stream: Readable, fileName: string, mode: number, targetPa
 
 	let istream: WriteStream;
 
-	Event.once(token.onCancellationRequested)(() => {
+	token.onCancellationRequested(() => {
 		if (istream) {
 			istream.destroy();
 		}
@@ -107,7 +106,7 @@ function extractZip(zipfile: ZipFile, targetPath: string, options: IOptions, tok
 	let last = createCancelablePromise<void>(() => Promise.resolve());
 	let extractedEntriesCount = 0;
 
-	Event.once(token.onCancellationRequested)(() => {
+	token.onCancellationRequested(() => {
 		last.cancel();
 		zipfile.close();
 	});
diff --git a/src/vs/monaco.d.ts b/src/vs/monaco.d.ts
index 87eaed8608c85..ff031806fb3ff 100644
--- a/src/vs/monaco.d.ts
+++ b/src/vs/monaco.d.ts
@@ -59,7 +59,10 @@ declare namespace monaco {
 		 */
 		readonly isCancellationRequested: boolean;
 		/**
-		 * An event which fires when cancellation is requested.
+		 * An event which fires when cancellation is requested. This event
+		 * only ever fires `once` as cancellation can only happen once. Listeners
+		 * that are registered after cancellation will be called (next event loop run),
+		 * but also only once.
 		 *
 		 * @event
 		 */
diff --git a/src/vs/workbench/services/remote/common/remoteAgentFileSystemChannel.ts b/src/vs/workbench/services/remote/common/remoteAgentFileSystemChannel.ts
index 71da8dc93e3df..1ef4d9c4bcffe 100644
--- a/src/vs/workbench/services/remote/common/remoteAgentFileSystemChannel.ts
+++ b/src/vs/workbench/services/remote/common/remoteAgentFileSystemChannel.ts
@@ -3,7 +3,7 @@
  *  Licensed under the MIT License. See License.txt in the project root for license information.
  *--------------------------------------------------------------------------------------------*/
 
-import { Emitter, Event } from 'vs/base/common/event';
+import { Emitter } from 'vs/base/common/event';
 import { Disposable, IDisposable, toDisposable } from 'vs/base/common/lifecycle';
 import { URI, UriComponents } from 'vs/base/common/uri';
 import { generateUuid } from 'vs/base/common/uuid';
@@ -153,7 +153,7 @@ export class RemoteFileSystemProvider extends Disposable implements
 
 		// Support cancellation
 		if (token) {
-			Event.once(token.onCancellationRequested)(() => {
+			token.onCancellationRequested(() => {
 
 				// Ensure to end the stream properly with an error
 				// to indicate the cancellation.