67 lines
1.8 KiB
TypeScript
67 lines
1.8 KiB
TypeScript
interface RequestQueueItem {
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request: (canceller?: RequestCanceller) => Promise<any>;
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callback: (response) => void;
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isCanceled: { status: boolean };
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canceller: { exec: () => void };
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}
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interface RequestCanceller {
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exec: () => void;
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}
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export default class QueueProcessor<T> {
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private requestQueue: RequestQueueItem[] = [];
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private requestInProcessing = 0;
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constructor(private maxParallelProcesses: number) {}
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public queueUpRequest(request: () => Promise<T>) {
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const isCanceled = { status: false };
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const canceller: RequestCanceller = {
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exec: () => {
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isCanceled.status = true;
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},
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};
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const promise = new Promise<T>((resolve) => {
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this.requestQueue.push({
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request,
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callback: resolve,
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isCanceled,
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canceller,
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});
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this.pollQueue();
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});
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return { promise, canceller };
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}
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async pollQueue() {
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if (this.requestInProcessing < this.maxParallelProcesses) {
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this.requestInProcessing++;
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await this.processQueue();
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this.requestInProcessing--;
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}
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}
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public async processQueue() {
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while (this.requestQueue.length > 0) {
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const queueItem = this.requestQueue.pop();
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let response: string;
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if (queueItem.isCanceled.status) {
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response = null;
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} else {
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try {
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response = await queueItem.request(queueItem.canceller);
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} catch (e) {
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response = null;
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}
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}
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queueItem.callback(response);
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await this.processQueue();
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}
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}
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}
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