| 1 | ;
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| 2 | /*! *****************************************************************************
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| 3 | Copyright (c) Microsoft Corporation.
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| 4 | Licensed under the Apache License, Version 2.0.
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| 5 |
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| 6 | See LICENSE file in the project root for details.
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| 7 | ***************************************************************************** */
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| 8 | Object.defineProperty(exports, "__esModule", { value: true });
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| 9 | const utils_1 = require("./utils");
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| 10 | /**
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| 11 | * An asynchronous queue.
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| 12 | */
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| 13 | class AsyncQueue {
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| 14 | /**
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| 15 | * Initializes a new instance of the AsyncQueue class.
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| 16 | *
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| 17 | * @param iterable An optional iterable of values or promises.
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| 18 | */
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| 19 | constructor(iterable) {
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| 20 | this._available = undefined;
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| 21 | this._pending = undefined;
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| 22 | if (!utils_1.isIterable(iterable, /*optional*/ true))
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| 23 | throw new TypeError("Object not iterable: iterable.");
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| 24 | if (!utils_1.isMissing(iterable)) {
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| 25 | this._available = [];
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| 26 | for (const value of iterable) {
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| 27 | this._available.push(Promise.resolve(value));
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| 28 | }
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| 29 | }
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| 30 | }
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| 31 | /**
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| 32 | * Gets the number of entries in the queue.
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| 33 | * When positive, indicates the number of entries available to get.
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| 34 | * When negative, indicates the number of requests waiting to be fulfilled.
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| 35 | */
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| 36 | get size() {
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| 37 | if (this._available && this._available.length > 0) {
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| 38 | return this._available.length;
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| 39 | }
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| 40 | if (this._pending && this._pending.length > 0) {
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| 41 | return -this._pending.length;
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| 42 | }
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| 43 | return 0;
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| 44 | }
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| 45 | /**
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| 46 | * Adds a value to the end of the queue. If the queue is empty but has a pending
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| 47 | * dequeue request, the value will be dequeued and the request fulfilled.
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| 48 | *
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| 49 | * @param value A value or promise to add to the queue.
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| 50 | */
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| 51 | put(value) {
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| 52 | if (this._pending !== undefined) {
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| 53 | const resolve = this._pending.shift();
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| 54 | if (resolve !== undefined) {
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| 55 | resolve(value);
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| 56 | return;
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| 57 | }
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| 58 | }
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| 59 | if (this._available === undefined) {
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| 60 | this._available = [];
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| 61 | }
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| 62 | this._available.push(Promise.resolve(value));
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| 63 | }
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| 64 | /**
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| 65 | * Removes and returns a Promise for the first value in the queue. If the queue is empty,
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| 66 | * returns a Promise for the next value to be added to the queue.
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| 67 | */
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| 68 | get() {
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| 69 | if (this._available !== undefined) {
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| 70 | const promise = this._available.shift();
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| 71 | if (promise !== undefined) {
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| 72 | return promise;
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| 73 | }
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| 74 | }
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| 75 | if (this._pending === undefined) {
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| 76 | this._pending = [];
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| 77 | }
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| 78 | return new Promise(resolve => { this._pending.push(resolve); });
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| 79 | }
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| 80 | }
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| 81 | exports.AsyncQueue = AsyncQueue;
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