manualPromise.ts•3.57 kB
/**
* Copyright (c) Microsoft Corporation.
*
* 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.
*/
export class ManualPromise<T = void> extends Promise<T> {
private _resolve!: (t: T) => void;
private _reject!: (e: Error) => void;
private _isDone: boolean;
constructor() {
let resolve: (t: T) => void;
let reject: (e: Error) => void;
super((f, r) => {
resolve = f;
reject = r;
});
this._isDone = false;
this._resolve = resolve!;
this._reject = reject!;
}
isDone() {
return this._isDone;
}
resolve(t: T) {
this._isDone = true;
this._resolve(t);
}
reject(e: Error) {
this._isDone = true;
this._reject(e);
}
static override get [Symbol.species]() {
return Promise;
}
override get [Symbol.toStringTag]() {
return 'ManualPromise';
}
}
export class LongStandingScope {
private _terminateError: Error | undefined;
private _closeError: Error | undefined;
private _terminatePromises = new Map<ManualPromise<Error>, string[]>();
private _isClosed = false;
reject(error: Error) {
this._isClosed = true;
this._terminateError = error;
for (const p of this._terminatePromises.keys())
p.resolve(error);
}
close(error: Error) {
this._isClosed = true;
this._closeError = error;
for (const [p, frames] of this._terminatePromises)
p.resolve(cloneError(error, frames));
}
isClosed() {
return this._isClosed;
}
static async raceMultiple<T>(scopes: LongStandingScope[], promise: Promise<T>): Promise<T> {
return Promise.race(scopes.map(s => s.race(promise)));
}
async race<T>(promise: Promise<T> | Promise<T>[]): Promise<T> {
return this._race(Array.isArray(promise) ? promise : [promise], false) as Promise<T>;
}
async safeRace<T>(promise: Promise<T>, defaultValue?: T): Promise<T> {
return this._race([promise], true, defaultValue);
}
private async _race(promises: Promise<any>[], safe: boolean, defaultValue?: any): Promise<any> {
const terminatePromise = new ManualPromise<Error>();
const frames = captureRawStack();
if (this._terminateError)
terminatePromise.resolve(this._terminateError);
if (this._closeError)
terminatePromise.resolve(cloneError(this._closeError, frames));
this._terminatePromises.set(terminatePromise, frames);
try {
return await Promise.race([
terminatePromise.then(e => safe ? defaultValue : Promise.reject(e)),
...promises
]);
} finally {
this._terminatePromises.delete(terminatePromise);
}
}
}
function cloneError(error: Error, frames: string[]) {
const clone = new Error();
clone.name = error.name;
clone.message = error.message;
clone.stack = [error.name + ':' + error.message, ...frames].join('\n');
return clone;
}
function captureRawStack(): string[] {
const stackTraceLimit = Error.stackTraceLimit;
Error.stackTraceLimit = 50;
const error = new Error();
const stack = error.stack || '';
Error.stackTraceLimit = stackTraceLimit;
return stack.split('\n');
}