// (C) Copyright 2015 Moodle Pty Ltd. // // Licensed under the Apache License, Version 2.0 (the "License"); // you may not use this file except in compliance with the License. // You may obtain a copy of the License at // // http://www.apache.org/licenses/LICENSE-2.0 // // Unless required by applicable law or agreed to in writing, software // distributed under the License is distributed on an "AS IS" BASIS, // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. // See the License for the specific language governing permissions and // limitations under the License. import { CorePromise } from '@classes/promise'; /** * Promise whose execution can be cancelled. */ export class CoreCancellablePromise extends CorePromise { /** * Create a new resolved promise. * * @returns Resolved promise. */ static resolve(): CoreCancellablePromise; static resolve(result: T): CoreCancellablePromise; static resolve(result?: T): CoreCancellablePromise { return new this(resolve => result ? resolve(result) : (resolve as () => void)(), () => { // Nothing to do here. }); } protected cancelPromise: () => void; constructor( executor: (resolve: (value: T | PromiseLike) => void, reject: (reason?: Error) => void) => void, cancelPromise: () => void, ) { super(new Promise(executor)); this.cancelPromise = cancelPromise; } /** * Cancel promise. * * After this method is called, the promise will remain unresolved forever. Make sure that after calling * this method there aren't any references to this object, or it could cause memory leaks. */ cancel(): void { this.cancelPromise(); } }