187 lines
4.8 KiB
JavaScript
187 lines
4.8 KiB
JavaScript
const has = Object.prototype.hasOwnProperty;
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class QueueEvent extends Event {
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constructor(name, detail) {
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super(name);
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this.detail = detail;
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}
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}
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class Queue extends EventTarget {
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constructor(options = {}) {
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super();
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const { concurrency = Infinity, timeout = 0, autostart = false, results = null } = options;
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this.concurrency = concurrency;
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this.timeout = timeout;
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this.autostart = autostart;
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this.results = results;
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this.pending = 0;
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this.session = 0;
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this.running = false;
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this.jobs = [];
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this.timers = [];
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this.addEventListener("error", this._errorHandler);
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}
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_errorHandler(evt) {
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this.end(evt.detail.error);
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}
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pop() {
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return this.jobs.pop();
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}
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shift() {
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return this.jobs.shift();
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}
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indexOf(searchElement, fromIndex) {
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return this.jobs.indexOf(searchElement, fromIndex);
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}
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lastIndexOf(searchElement, fromIndex) {
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if (fromIndex !== void 0) {
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return this.jobs.lastIndexOf(searchElement, fromIndex);
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}
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return this.jobs.lastIndexOf(searchElement);
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}
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slice(start, end) {
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this.jobs = this.jobs.slice(start, end);
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return this;
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}
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reverse() {
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this.jobs.reverse();
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return this;
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}
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push(...workers) {
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const methodResult = this.jobs.push(...workers);
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if (this.autostart) {
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this.start();
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}
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return methodResult;
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}
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unshift(...workers) {
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const methodResult = this.jobs.unshift(...workers);
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if (this.autostart) {
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this.start();
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}
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return methodResult;
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}
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splice(start, deleteCount, ...workers) {
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this.jobs.splice(start, deleteCount, ...workers);
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if (this.autostart) {
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this.start();
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}
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return this;
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}
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get length() {
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return this.pending + this.jobs.length;
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}
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start(callback) {
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let awaiter;
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if (callback) {
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this._addCallbackToEndEvent(callback);
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} else {
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awaiter = this._createPromiseToEndEvent();
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}
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this.running = true;
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if (this.pending >= this.concurrency) {
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return;
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}
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if (this.jobs.length === 0) {
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if (this.pending === 0) {
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this.done();
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}
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return;
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}
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const job = this.jobs.shift();
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const session = this.session;
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const timeout = job !== void 0 && has.call(job, "timeout") ? job.timeout : this.timeout;
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let once = true;
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let timeoutId = null;
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let didTimeout = false;
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let resultIndex = null;
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const next = (error, ...result) => {
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if (once && this.session === session) {
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once = false;
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this.pending--;
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if (timeoutId !== null) {
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this.timers = this.timers.filter((tID) => tID !== timeoutId);
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clearTimeout(timeoutId);
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}
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if (error) {
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this.dispatchEvent(new QueueEvent("error", { error, job }));
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} else if (!didTimeout) {
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if (resultIndex !== null && this.results !== null) {
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this.results[resultIndex] = [...result];
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}
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this.dispatchEvent(new QueueEvent("success", { result: [...result], job }));
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}
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if (this.session === session) {
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if (this.pending === 0 && this.jobs.length === 0) {
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this.done();
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} else if (this.running) {
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this.start();
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}
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}
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}
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};
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if (timeout) {
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timeoutId = setTimeout(() => {
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didTimeout = true;
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this.dispatchEvent(new QueueEvent("timeout", { next, job }));
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next();
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}, timeout);
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this.timers.push(timeoutId);
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}
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if (this.results != null) {
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resultIndex = this.results.length;
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this.results[resultIndex] = null;
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}
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this.pending++;
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this.dispatchEvent(new QueueEvent("start", { job }));
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const promise = job(next);
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if (promise !== void 0 && typeof promise.then === "function") {
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promise.then(function(result) {
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return next(void 0, result);
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}).catch(function(err) {
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return next(err || true);
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});
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}
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if (this.running && this.jobs.length > 0) {
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return this.start();
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}
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return awaiter;
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}
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stop() {
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this.running = false;
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}
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end(error) {
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this.clearTimers();
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this.jobs.length = 0;
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this.pending = 0;
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this.done(error);
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}
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clearTimers() {
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this.timers.forEach((timer) => {
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clearTimeout(timer);
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});
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this.timers = [];
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}
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_addCallbackToEndEvent(cb) {
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const onend = (evt) => {
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this.removeEventListener("end", onend);
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cb(evt.detail.error, this.results);
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};
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this.addEventListener("end", onend);
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}
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_createPromiseToEndEvent() {
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return new Promise((resolve) => {
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this._addCallbackToEndEvent((error, results) => {
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resolve({ error, results });
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});
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});
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}
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done(error) {
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this.session++;
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this.running = false;
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this.dispatchEvent(new QueueEvent("end", { error }));
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}
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}
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export {
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QueueEvent,
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Queue as default
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};
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