Source: lib/polyfill/abort_controller.js

  1. /*! @license
  2.  * Shaka Player
  3.  * Copyright 2016 Google LLC
  4.  * SPDX-License-Identifier: Apache-2.0
  5.  */
  7. goog.provide('shaka.polyfill.AbortController');
  9. goog.require('shaka.polyfill');
  10. goog.require('shaka.util.FakeEvent');
  11. goog.require('shaka.util.FakeEventTarget');
  13. /**
  14.  * @summary A polyfill for systems that do not implement AbortController.
  15.  * This is used both with the fetch API for HTTP requests and inside the HLS
  16.  * parser.
  17.  * @export
  18.  * @extends AbortController
  19.  */
  20. shaka.polyfill.AbortController = class {
  21.   /**
  22.    * Install the polyfill if needed.
  23.    * @export
  24.    */
  25.   static install() {
  26.     if (window.AbortController) {
  27.       // Not needed.
  28.       return;
  29.     }
  31.     window.AbortController = shaka.polyfill.AbortController;
  32.     window.AbortSignal = shaka.polyfill.AbortController.AbortSignal;
  33.   }
  35.   /** */
  36.   constructor() {
  37.     /** @private {!shaka.polyfill.AbortController.AbortSignal} */
  38.     this.signal_ = new shaka.polyfill.AbortController.AbortSignal();
  39.   }
  41.   /**
  42.    * @override
  43.    * @suppress {const|duplicate} Since the original is defined as "const", we
  44.    *   need this suppression to override it.
  45.    */
  46.   get signal() {
  47.     return this.signal_;
  48.   }
  50.   /**
  51.    * @param {*=} reason
  52.    * @override
  53.    */
  54.   abort(reason) {
  55.     this.signal_.doAbort_(reason);
  56.   }
  57. };
  59. /**
  60.  * @summary A polyfill for AbortSignal, part of the AbortController API.
  61.  * @implements {AbortSignal}
  62.  */
  63. shaka.polyfill.AbortController.AbortSignal =
  64. class extends shaka.util.FakeEventTarget {
  65.   /** */
  66.   constructor() {
  67.     super();
  69.     /** @private {boolean} */
  70.     this.aborted_ = false;
  72.     /** @private {*} */
  73.     this.reason_ = undefined;
  75.     /** @type {?function(!Event)} */
  76.     this.onabort = null;
  77.   }
  79.   /** @override */
  80.   get aborted() {
  81.     return this.aborted_;
  82.   }
  84.   /** @return {*} */
  85.   get reason() {
  86.     return this.reason_;
  87.   }
  89.   /** @return {void} */
  90.   throwIfAborted() {
  91.     if (this.aborted_) {
  92.       throw this.reason_;
  93.     }
  94.   }
  96.   /**
  97.    * @param {*} reason
  98.    * @private
  99.    */
  100.   doAbort_(reason) {
  101.     if (this.aborted_) {
  102.       return;
  103.     }
  105.     this.aborted_ = true;
  106.     this.reason_ = reason;
  107.     if (this.reason_ === undefined) {
  108.       // This is equivalent to a native implementation.
  109.       this.reason_ = new DOMException(
  110.           'signal is aborted without reason', 'AbortError');
  111.     }
  113.     // According to MDN:
  114.     // "Event type - A generic Event with no added properties."
  115.     const event = new shaka.util.FakeEvent('abort');
  116.     if (this.onabort) {
  117.       this.onabort(event);
  118.     }
  119.     this.dispatchEvent(event);
  120.   }
  123.   /**
  124.    * @param {*=} reason
  125.    * @return {!AbortSignal}
  126.    */
  127.   static abort(reason) {
  128.     const signal = new shaka.polyfill.AbortController.AbortSignal();
  129.     signal.doAbort_(reason);
  130.     return signal;
  131.   }
  133.   /**
  134.    * @param {number} timeMs
  135.    * @return {!AbortSignal}
  136.    */
  137.   static timeout(timeMs) {
  138.     const signal = new shaka.polyfill.AbortController.AbortSignal();
  140.     window.setTimeout(() => {
  141.       // This is equivalent to a native implementation.
  142.       signal.doAbort_(new DOMException('signal timed out', 'TimeoutError'));
  143.     }, timeMs);
  145.     return signal;
  146.   }
  147. };
  150. shaka.polyfill.register(shaka.polyfill.AbortController.install);