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| 1 | +import { promiseWithResolvers } from '../jsutils/promiseWithResolvers.js'; |
| 2 | + |
| 3 | +/** |
| 4 | + * A AbortSignalListener object can be used to trigger multiple responses |
| 5 | + * in response to an abort signal. |
| 6 | + * |
| 7 | + * @internal |
| 8 | + */ |
| 9 | +export class AbortSignalListener { |
| 10 | + abortSignal: AbortSignal; |
| 11 | + abort: () => void; |
| 12 | + |
| 13 | + private _aborts: Set<() => void>; |
| 14 | + |
| 15 | + constructor(abortSignal: AbortSignal) { |
| 16 | + this.abortSignal = abortSignal; |
| 17 | + this._aborts = new Set<() => void>(); |
| 18 | + this.abort = () => { |
| 19 | + for (const abort of this._aborts) { |
| 20 | + abort(); |
| 21 | + } |
| 22 | + }; |
| 23 | + |
| 24 | + abortSignal.addEventListener('abort', this.abort); |
| 25 | + } |
| 26 | + |
| 27 | + disconnect(): void { |
| 28 | + this.abortSignal.removeEventListener('abort', this.abort); |
| 29 | + } |
| 30 | + |
| 31 | + cancellablePromise<T>( |
| 32 | + originalPromise: Promise<T>, |
| 33 | + onCancel?: (() => unknown) | undefined, |
| 34 | + ): Promise<T> { |
| 35 | + if (this.abortSignal.aborted) { |
| 36 | + onCancel?.(); |
| 37 | + // eslint-disable-next-line @typescript-eslint/prefer-promise-reject-errors |
| 38 | + return Promise.reject(this.abortSignal.reason); |
| 39 | + } |
| 40 | + |
| 41 | + const { promise, resolve, reject } = promiseWithResolvers<T>(); |
| 42 | + const abort = () => { |
| 43 | + onCancel?.(); |
| 44 | + reject(this.abortSignal.reason); |
| 45 | + }; |
| 46 | + this._aborts.add(abort); |
| 47 | + originalPromise.then( |
| 48 | + (resolved) => { |
| 49 | + this._aborts.delete(abort); |
| 50 | + resolve(resolved); |
| 51 | + }, |
| 52 | + (error: unknown) => { |
| 53 | + this._aborts.delete(abort); |
| 54 | + reject(error); |
| 55 | + }, |
| 56 | + ); |
| 57 | + |
| 58 | + return promise; |
| 59 | + } |
| 60 | + |
| 61 | + cancellableIterable<T>(iterable: AsyncIterable<T>): AsyncIterable<T> { |
| 62 | + const iterator = iterable[Symbol.asyncIterator](); |
| 63 | + |
| 64 | + if (iterator.return) { |
| 65 | + const _return = iterator.return.bind(iterator); |
| 66 | + const _returnIgnoringErrors = async (): Promise<IteratorResult<T>> => { |
| 67 | + _return().catch(() => { |
| 68 | + /* c8 ignore next */ |
| 69 | + // ignore |
| 70 | + }); |
| 71 | + return Promise.resolve({ value: undefined, done: true }); |
| 72 | + }; |
| 73 | + |
| 74 | + return { |
| 75 | + [Symbol.asyncIterator]: () => ({ |
| 76 | + next: () => |
| 77 | + this.cancellablePromise(iterator.next(), _returnIgnoringErrors), |
| 78 | + return: () => this.cancellablePromise(_return()), |
| 79 | + }), |
| 80 | + }; |
| 81 | + } |
| 82 | + |
| 83 | + return { |
| 84 | + [Symbol.asyncIterator]: () => ({ |
| 85 | + next: () => this.cancellablePromise(iterator.next()), |
| 86 | + }), |
| 87 | + }; |
| 88 | + } |
| 89 | +} |
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