Source: lib/polyfill/patchedmediakeys_nop.js

  1. /*! @license
  2.  * Shaka Player
  3.  * Copyright 2016 Google LLC
  4.  * SPDX-License-Identifier: Apache-2.0
  5.  */
  7. goog.provide('shaka.polyfill.PatchedMediaKeysNop');
  9. goog.require('goog.asserts');
  10. goog.require('shaka.log');
  11. goog.require('shaka.polyfill');
  14. /**
  15.  * @summary A polyfill to stub out
  16.  * {@link https://bit.ly/EmeMar15 EME draft 12 March 2015} on browsers without
  17.  * EME.
  18.  * All methods will fail.
  19.  * @export
  20.  */
  21. shaka.polyfill.PatchedMediaKeysNop = class {
  22.   /**
  23.    * Installs the polyfill if needed.
  24.    * @export
  25.    */
  26.   static install() {
  27.     if (!window.HTMLVideoElement ||
  28.         (navigator.requestMediaKeySystemAccess &&
  29.          // eslint-disable-next-line no-restricted-syntax
  30.          MediaKeySystemAccess.prototype.getConfiguration)) {
  31.       return;
  32.     }
  33.     shaka.log.info('EME not available.');
  35.     // Alias.
  36.     const PatchedMediaKeysNop = shaka.polyfill.PatchedMediaKeysNop;
  38.     // Install patches.
  39.     navigator.requestMediaKeySystemAccess =
  40.         PatchedMediaKeysNop.requestMediaKeySystemAccess;
  41.     // Delete mediaKeys to work around strict mode compatibility issues.
  42.     // eslint-disable-next-line no-restricted-syntax
  43.     delete HTMLMediaElement.prototype['mediaKeys'];
  44.     // Work around read-only declaration for mediaKeys by using a string.
  45.     // eslint-disable-next-line no-restricted-syntax
  46.     HTMLMediaElement.prototype['mediaKeys'] = null;
  47.     // eslint-disable-next-line no-restricted-syntax
  48.     HTMLMediaElement.prototype.setMediaKeys = PatchedMediaKeysNop.setMediaKeys;
  49.     // These are not usable, but allow Player.isBrowserSupported to pass.
  50.     window.MediaKeys = PatchedMediaKeysNop.MediaKeys;
  51.     window.MediaKeySystemAccess = PatchedMediaKeysNop.MediaKeySystemAccess;
  53.     window.shakaMediaKeysPolyfill = PatchedMediaKeysNop.apiName_;
  54.   }
  56.   /**
  57.    * An implementation of navigator.requestMediaKeySystemAccess.
  58.    * Retrieves a MediaKeySystemAccess object.
  59.    *
  60.    * @this {!Navigator}
  61.    * @param {string} keySystem
  62.    * @param {!Array.<!MediaKeySystemConfiguration>} supportedConfigurations
  63.    * @return {!Promise.<!MediaKeySystemAccess>}
  64.    */
  65.   static requestMediaKeySystemAccess(keySystem, supportedConfigurations) {
  66.     shaka.log.debug('PatchedMediaKeysNop.requestMediaKeySystemAccess');
  67.     goog.asserts.assert(this == navigator,
  68.         'bad "this" for requestMediaKeySystemAccess');
  70.     return Promise.reject(new Error(
  71.         'The key system specified is not supported.'));
  72.   }
  74.   /**
  75.    * An implementation of HTMLMediaElement.prototype.setMediaKeys.
  76.    * Attaches a MediaKeys object to the media element.
  77.    *
  78.    * @this {!HTMLMediaElement}
  79.    * @param {MediaKeys} mediaKeys
  80.    * @return {!Promise}
  81.    */
  82.   static setMediaKeys(mediaKeys) {
  83.     shaka.log.debug('PatchedMediaKeysNop.setMediaKeys');
  84.     goog.asserts.assert(this instanceof HTMLMediaElement,
  85.         'bad "this" for setMediaKeys');
  87.     if (mediaKeys == null) {
  88.       return Promise.resolve();
  89.     }
  91.     return Promise.reject(new Error('MediaKeys not supported.'));
  92.   }
  93. };
  96. /**
  97.  * An unusable constructor for MediaKeys.
  98.  * @implements {MediaKeys}
  99.  */
  100. shaka.polyfill.PatchedMediaKeysNop.MediaKeys = class {
  101.   /** */
  102.   constructor() {
  103.     throw new TypeError('Illegal constructor.');
  104.   }
  106.   /** @override */
  107.   createSession() {}
  109.   /** @override */
  110.   setServerCertificate() {}
  112.   /** @override */
  113.   getStatusForPolicy(policy) {
  114.     return Promise.resolve('usable');
  115.   }
  116. };
  119. /**
  120.  * An unusable constructor for MediaKeySystemAccess.
  121.  * @implements {MediaKeySystemAccess}
  122.  */
  123. shaka.polyfill.PatchedMediaKeysNop.MediaKeySystemAccess = class {
  124.   /** */
  125.   constructor() {
  126.     /** @override */
  127.     this.keySystem = '';  // For the compiler.
  129.     throw new TypeError('Illegal constructor.');
  130.   }
  132.   /** @override */
  133.   getConfiguration() {}
  135.   /** @override */
  136.   createMediaKeys() {}
  137. };
  139. /**
  140.  * API name.
  141.  *
  142.  * @private {string}
  143.  */
  144. shaka.polyfill.PatchedMediaKeysNop.apiName_ = 'nop';
  147. // A low priority ensures this is the last and acts as a fallback.
  148. shaka.polyfill.register(shaka.polyfill.PatchedMediaKeysNop.install, -10);