110 lines
3.6 KiB
JavaScript
110 lines
3.6 KiB
JavaScript
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/*---------------------------------------------------------------------------------------------
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* Copyright (c) Microsoft Corporation. All rights reserved.
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* Licensed under the MIT License. See License.txt in the project root for license information.
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*--------------------------------------------------------------------------------------------*/
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import { Emitter, Event } from './event.js';
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const shortcutEvent = Object.freeze(function (callback, context) {
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const handle = setTimeout(callback.bind(context), 0);
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return { dispose() { clearTimeout(handle); } };
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});
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export var CancellationToken;
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(function (CancellationToken) {
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function isCancellationToken(thing) {
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if (thing === CancellationToken.None || thing === CancellationToken.Cancelled) {
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return true;
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}
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if (thing instanceof MutableToken) {
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return true;
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}
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if (!thing || typeof thing !== 'object') {
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return false;
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}
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return typeof thing.isCancellationRequested === 'boolean'
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&& typeof thing.onCancellationRequested === 'function';
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}
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CancellationToken.isCancellationToken = isCancellationToken;
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CancellationToken.None = Object.freeze({
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isCancellationRequested: false,
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onCancellationRequested: Event.None
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});
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CancellationToken.Cancelled = Object.freeze({
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isCancellationRequested: true,
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onCancellationRequested: shortcutEvent
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});
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})(CancellationToken || (CancellationToken = {}));
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class MutableToken {
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constructor() {
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this._isCancelled = false;
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this._emitter = null;
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}
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cancel() {
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if (!this._isCancelled) {
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this._isCancelled = true;
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if (this._emitter) {
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this._emitter.fire(undefined);
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this.dispose();
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}
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}
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}
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get isCancellationRequested() {
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return this._isCancelled;
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}
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get onCancellationRequested() {
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if (this._isCancelled) {
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return shortcutEvent;
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}
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if (!this._emitter) {
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this._emitter = new Emitter();
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}
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return this._emitter.event;
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}
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dispose() {
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if (this._emitter) {
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this._emitter.dispose();
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this._emitter = null;
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}
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}
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}
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export class CancellationTokenSource {
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constructor(parent) {
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this._token = undefined;
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this._parentListener = undefined;
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this._parentListener = parent && parent.onCancellationRequested(this.cancel, this);
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}
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get token() {
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if (!this._token) {
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// be lazy and create the token only when
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// actually needed
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this._token = new MutableToken();
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}
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return this._token;
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}
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cancel() {
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if (!this._token) {
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// save an object by returning the default
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// cancelled token when cancellation happens
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// before someone asks for the token
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this._token = CancellationToken.Cancelled;
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}
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else if (this._token instanceof MutableToken) {
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// actually cancel
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this._token.cancel();
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}
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}
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dispose(cancel = false) {
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var _a;
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if (cancel) {
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this.cancel();
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}
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(_a = this._parentListener) === null || _a === void 0 ? void 0 : _a.dispose();
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if (!this._token) {
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// ensure to initialize with an empty token if we had none
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this._token = CancellationToken.None;
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}
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else if (this._token instanceof MutableToken) {
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// actually dispose
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this._token.dispose();
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}
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}
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}
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