Squashed 'lib/vscode/' content from commit e5a624b788

git-subtree-dir: lib/vscode
git-subtree-split: e5a624b788d92b8d34d1392e4c4d9789406efe8f

extensions/github-authentication/src/common/utils.ts

@@ -0,0 +1,73 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+import { Event, Disposable } from 'vscode';
+
+export function filterEvent<T>(event: Event<T>, filter: (e: T) => boolean): Event<T> {
+	return (listener, thisArgs = null, disposables?) => event(e => filter(e) && listener.call(thisArgs, e), null, disposables);
+}
+
+export function onceEvent<T>(event: Event<T>): Event<T> {
+	return (listener, thisArgs = null, disposables?) => {
+		const result = event(e => {
+			result.dispose();
+			return listener.call(thisArgs, e);
+		}, null, disposables);
+
+		return result;
+	};
+}
+
+
+export interface PromiseAdapter<T, U> {
+	(
+		value: T,
+		resolve:
+			(value: U | PromiseLike<U>) => void,
+		reject:
+			(reason: any) => void
+	): any;
+}
+
+const passthrough = (value: any, resolve: (value?: any) => void) => resolve(value);
+
+/**
+ * Return a promise that resolves with the next emitted event, or with some future
+ * event as decided by an adapter.
+ *
+ * If specified, the adapter is a function that will be called with
+ * `(event, resolve, reject)`. It will be called once per event until it resolves or
+ * rejects.
+ *
+ * The default adapter is the passthrough function `(value, resolve) => resolve(value)`.
+ *
+ * @param event the event
+ * @param adapter controls resolution of the returned promise
+ * @returns a promise that resolves or rejects as specified by the adapter
+ */
+export async function promiseFromEvent<T, U>(
+	event: Event<T>,
+	adapter: PromiseAdapter<T, U> = passthrough): Promise<U> {
+	let subscription: Disposable;
+	return new Promise<U>((resolve, reject) =>
+		subscription = event((value: T) => {
+			try {
+				Promise.resolve(adapter(value, resolve, reject))
+					.catch(reject);
+			} catch (error) {
+				reject(error);
+			}
+		})
+	).then(
+		(result: U) => {
+			subscription.dispose();
+			return result;
+		},
+		error => {
+			subscription.dispose();
+			throw error;
+		}
+	);
+}