324 lines
8.1 KiB
JavaScript
324 lines
8.1 KiB
JavaScript
/*
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MIT License http://www.opensource.org/licenses/mit-license.php
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Author Tobias Koppers @sokra
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*/
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"use strict";
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const { SyncHook, AsyncSeriesHook } = require("tapable");
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const ArrayQueue = require("./ArrayQueue");
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const QUEUED_STATE = 0;
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const PROCESSING_STATE = 1;
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const DONE_STATE = 2;
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let inHandleResult = 0;
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/**
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* @template T
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* @callback Callback
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* @param {Error=} err
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* @param {T=} result
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*/
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/**
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* @template T
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* @template K
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* @template R
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*/
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class AsyncQueueEntry {
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/**
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* @param {T} item the item
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* @param {Callback<R>} callback the callback
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*/
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constructor(item, callback) {
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this.item = item;
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/** @type {typeof QUEUED_STATE | typeof PROCESSING_STATE | typeof DONE_STATE} */
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this.state = QUEUED_STATE;
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this.callback = callback;
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/** @type {Callback<R>[] | undefined} */
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this.callbacks = undefined;
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this.result = undefined;
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this.error = undefined;
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}
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}
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/**
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* @template T
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* @template K
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* @template R
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*/
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class AsyncQueue {
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/**
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* @param {Object} options options object
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* @param {string=} options.name name of the queue
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* @param {number=} options.parallelism how many items should be processed at once
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* @param {AsyncQueue<any, any, any>=} options.parent parent queue, which will have priority over this queue and with shared parallelism
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* @param {function(T): K=} options.getKey extract key from item
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* @param {function(T, Callback<R>): void} options.processor async function to process items
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*/
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constructor({ name, parallelism, parent, processor, getKey }) {
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this._name = name;
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this._parallelism = parallelism || 1;
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this._processor = processor;
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this._getKey =
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getKey || /** @type {(T) => K} */ (item => /** @type {any} */ (item));
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/** @type {Map<K, AsyncQueueEntry<T, K, R>>} */
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this._entries = new Map();
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/** @type {ArrayQueue<AsyncQueueEntry<T, K, R>>} */
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this._queued = new ArrayQueue();
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/** @type {AsyncQueue<any, any, any>[]} */
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this._children = undefined;
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this._activeTasks = 0;
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this._willEnsureProcessing = false;
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this._needProcessing = false;
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this._stopped = false;
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this._root = parent ? parent._root : this;
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if (parent) {
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if (this._root._children === undefined) {
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this._root._children = [this];
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} else {
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this._root._children.push(this);
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}
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}
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this.hooks = {
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/** @type {AsyncSeriesHook<[T]>} */
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beforeAdd: new AsyncSeriesHook(["item"]),
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/** @type {SyncHook<[T]>} */
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added: new SyncHook(["item"]),
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/** @type {AsyncSeriesHook<[T]>} */
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beforeStart: new AsyncSeriesHook(["item"]),
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/** @type {SyncHook<[T]>} */
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started: new SyncHook(["item"]),
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/** @type {SyncHook<[T, Error, R]>} */
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result: new SyncHook(["item", "error", "result"])
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};
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this._ensureProcessing = this._ensureProcessing.bind(this);
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}
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/**
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* @param {T} item a item
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* @param {Callback<R>} callback callback function
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* @returns {void}
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*/
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add(item, callback) {
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if (this._stopped) return callback(new Error("Queue was stopped"));
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this.hooks.beforeAdd.callAsync(item, err => {
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if (err) {
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callback(err);
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return;
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}
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const key = this._getKey(item);
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const entry = this._entries.get(key);
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if (entry !== undefined) {
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if (entry.state === DONE_STATE) {
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process.nextTick(() => callback(entry.error, entry.result));
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} else if (entry.callbacks === undefined) {
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entry.callbacks = [callback];
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} else {
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entry.callbacks.push(callback);
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}
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return;
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}
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const newEntry = new AsyncQueueEntry(item, callback);
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if (this._stopped) {
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this.hooks.added.call(item);
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this._root._activeTasks++;
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process.nextTick(() =>
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this._handleResult(newEntry, new Error("Queue was stopped"))
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);
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} else {
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this._entries.set(key, newEntry);
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this._queued.enqueue(newEntry);
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const root = this._root;
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root._needProcessing = true;
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if (root._willEnsureProcessing === false) {
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root._willEnsureProcessing = true;
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setImmediate(root._ensureProcessing);
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}
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this.hooks.added.call(item);
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}
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});
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}
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/**
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* @param {T} item a item
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* @returns {void}
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*/
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invalidate(item) {
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const key = this._getKey(item);
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const entry = this._entries.get(key);
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this._entries.delete(key);
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if (entry.state === QUEUED_STATE) {
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this._queued.delete(entry);
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}
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}
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/**
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* @returns {void}
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*/
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stop() {
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this._stopped = true;
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const queue = this._queued;
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this._queued = new ArrayQueue();
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const root = this._root;
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for (const entry of queue) {
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this._entries.delete(this._getKey(entry.item));
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root._activeTasks++;
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this._handleResult(entry, new Error("Queue was stopped"));
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}
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}
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/**
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* @returns {void}
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*/
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increaseParallelism() {
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const root = this._root;
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root._parallelism++;
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/* istanbul ignore next */
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if (root._willEnsureProcessing === false && root._needProcessing) {
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root._willEnsureProcessing = true;
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setImmediate(root._ensureProcessing);
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}
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}
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/**
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* @returns {void}
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*/
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decreaseParallelism() {
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const root = this._root;
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root._parallelism--;
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}
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/**
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* @param {T} item an item
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* @returns {boolean} true, if the item is currently being processed
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*/
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isProcessing(item) {
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const key = this._getKey(item);
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const entry = this._entries.get(key);
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return entry !== undefined && entry.state === PROCESSING_STATE;
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}
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/**
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* @param {T} item an item
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* @returns {boolean} true, if the item is currently queued
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*/
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isQueued(item) {
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const key = this._getKey(item);
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const entry = this._entries.get(key);
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return entry !== undefined && entry.state === QUEUED_STATE;
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}
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/**
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* @param {T} item an item
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* @returns {boolean} true, if the item is currently queued
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*/
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isDone(item) {
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const key = this._getKey(item);
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const entry = this._entries.get(key);
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return entry !== undefined && entry.state === DONE_STATE;
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}
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/**
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* @returns {void}
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*/
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_ensureProcessing() {
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while (this._activeTasks < this._parallelism) {
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const entry = this._queued.dequeue();
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if (entry === undefined) break;
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this._activeTasks++;
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entry.state = PROCESSING_STATE;
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this._startProcessing(entry);
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}
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this._willEnsureProcessing = false;
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if (this._queued.length > 0) return;
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if (this._children !== undefined) {
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for (const child of this._children) {
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while (this._activeTasks < this._parallelism) {
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const entry = child._queued.dequeue();
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if (entry === undefined) break;
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this._activeTasks++;
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entry.state = PROCESSING_STATE;
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child._startProcessing(entry);
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}
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if (child._queued.length > 0) return;
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}
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}
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if (!this._willEnsureProcessing) this._needProcessing = false;
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}
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/**
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* @param {AsyncQueueEntry<T, K, R>} entry the entry
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* @returns {void}
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*/
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_startProcessing(entry) {
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this.hooks.beforeStart.callAsync(entry.item, err => {
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if (err) {
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this._handleResult(entry, err);
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return;
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}
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let inCallback = false;
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try {
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this._processor(entry.item, (e, r) => {
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inCallback = true;
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this._handleResult(entry, e, r);
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});
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} catch (err) {
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if (inCallback) throw err;
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this._handleResult(entry, err, null);
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}
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this.hooks.started.call(entry.item);
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});
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}
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/**
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* @param {AsyncQueueEntry<T, K, R>} entry the entry
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* @param {Error=} err error, if any
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* @param {R=} result result, if any
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* @returns {void}
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*/
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_handleResult(entry, err, result) {
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this.hooks.result.callAsync(entry.item, err, result, hookError => {
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const error = hookError || err;
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const callback = entry.callback;
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const callbacks = entry.callbacks;
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entry.state = DONE_STATE;
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entry.callback = undefined;
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entry.callbacks = undefined;
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entry.result = result;
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entry.error = error;
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const root = this._root;
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root._activeTasks--;
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if (root._willEnsureProcessing === false && root._needProcessing) {
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root._willEnsureProcessing = true;
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setImmediate(root._ensureProcessing);
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}
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if (inHandleResult++ > 3) {
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process.nextTick(() => {
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callback(error, result);
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if (callbacks !== undefined) {
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for (const callback of callbacks) {
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callback(error, result);
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}
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}
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});
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} else {
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callback(error, result);
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if (callbacks !== undefined) {
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for (const callback of callbacks) {
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callback(error, result);
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}
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}
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}
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inHandleResult--;
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});
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}
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}
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module.exports = AsyncQueue;
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