Source: lib/cast/cast_utils.js

  1. /**
  2.  * @license
  3.  * Copyright 2016 Google Inc.
  4.  *
  5.  * Licensed under the Apache License, Version 2.0 (the "License");
  6.  * you may not use this file except in compliance with the License.
  7.  * You may obtain a copy of the License at
  8.  *
  9.  *     http://www.apache.org/licenses/LICENSE-2.0
  10.  *
  11.  * Unless required by applicable law or agreed to in writing, software
  12.  * distributed under the License is distributed on an "AS IS" BASIS,
  13.  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  14.  * See the License for the specific language governing permissions and
  15.  * limitations under the License.
  16.  */
  18. goog.provide('shaka.cast.CastUtils');
  20. goog.require('shaka.util.FakeEvent');
  23. /**
  24.  * @namespace shaka.cast.CastUtils
  25.  * @summary A set of cast utility functions and variables shared between sender
  26.  *   and receiver.
  27.  */
  30. /**
  31.  * HTMLMediaElement events that are proxied while casting.
  32.  * @const {!Array.<string>}
  33.  */
  34. shaka.cast.CastUtils.VideoEvents = [
  35.   'ended',
  36.   'play',
  37.   'playing',
  38.   'pause',
  39.   'pausing',
  40.   'ratechange',
  41.   'seeked',
  42.   'seeking',
  43.   'timeupdate',
  44.   'volumechange',
  45. ];
  48. /**
  49.  * HTMLMediaElement attributes that are proxied while casting.
  50.  * @const {!Array.<string>}
  51.  */
  52. shaka.cast.CastUtils.VideoAttributes = [
  53.   'buffered',
  54.   'currentTime',
  55.   'duration',
  56.   'ended',
  57.   'loop',
  58.   'muted',
  59.   'paused',
  60.   'playbackRate',
  61.   'seeking',
  62.   'videoHeight',
  63.   'videoWidth',
  64.   'volume',
  65. ];
  68. /**
  69.  * HTMLMediaElement attributes that are transferred when casting begins.
  70.  * @const {!Array.<string>}
  71.  */
  72. shaka.cast.CastUtils.VideoInitStateAttributes = [
  73.   'loop',
  74.   'playbackRate',
  75. ];
  78. /**
  79.  * HTMLMediaElement methods with no return value that are proxied while casting.
  80.  * @const {!Array.<string>}
  81.  */
  82. shaka.cast.CastUtils.VideoVoidMethods = [
  83.   'pause',
  84.   'play',
  85. ];
  88. /**
  89.  * Player events that are proxied while casting.
  90.  * @const {!Array.<string>}
  91.  */
  92. shaka.cast.CastUtils.PlayerEvents = [
  93.   'adaptation',
  94.   'buffering',
  95.   'emsg',
  96.   'error',
  97.   'loading',
  98.   'streaming',
  99.   'texttrackvisibility',
  100.   'timelineregionadded',
  101.   'timelineregionenter',
  102.   'timelineregionexit',
  103.   'trackschanged',
  104.   'unloading',
  105. ];
  108. /**
  109.  * Player getter methods that are proxied while casting.
  110.  * The key is the method, the value is the frequency of updates.
  111.  * Frequency 1 translates to every update; frequency 2 to every 2 updates, etc.
  112.  * @const {!Object.<string, number>}
  113.  */
  114. shaka.cast.CastUtils.PlayerGetterMethods = {
  115.   // NOTE: The 'drmInfo' property is not proxied, as it is very large.
  116.   'getAssetUri': 2,
  117.   'getAudioLanguages': 2,
  118.   'getAudioLanguagesAndRoles': 2,
  119.   'getBufferedInfo': 2,
  120.   // NOTE: The 'getSharedConfiguration' property is not proxied as it would
  121.   //       not be possible to share a reference.
  122.   'getConfiguration': 2,
  123.   'getExpiration': 2,
  124.   // NOTE: The 'getManifest' property is not proxied, as it is very large.
  125.   // TODO(vaage): Remove |getManifestUri| references in v2.6.
  126.   // NOTE: The 'getManifestUri' property is not proxied, as CastProxy has a
  127.   // handler for it.
  128.   'getPlaybackRate': 2,
  129.   'getTextLanguages': 2,
  130.   'getTextLanguagesAndRoles': 2,
  131.   'getTextTracks': 2,
  132.   'getStats': 5,
  133.   'usingEmbeddedTextTrack': 2,
  134.   'getVariantTracks': 2,
  135.   'isAudioOnly': 10,
  136.   'isBuffering': 1,
  137.   'isInProgress': 1,
  138.   'isLive': 10,
  139.   'isTextTrackVisible': 1,
  140.   'keySystem': 10,
  141.   'seekRange': 1,
  142. };
  145. /**
  146.  * Player getter methods that are proxied while casting, but only when casting
  147.  * a livestream.
  148.  * The key is the method, the value is the frequency of updates.
  149.  * Frequency 1 translates to every update; frequency 2 to every 2 updates, etc.
  150.  * @const {!Object.<string, number>}
  151.  */
  152. shaka.cast.CastUtils.PlayerGetterMethodsThatRequireLive = {
  153.   'getPlayheadTimeAsDate': 1,
  154.   'getPresentationStartTimeAsDate': 20,
  155. };
  158. /**
  159.  * Player getter and setter methods that are used to transfer state when casting
  160.  * begins.
  161.  * @const {!Array.<!Array.<string>>}
  162.  */
  163. shaka.cast.CastUtils.PlayerInitState = [
  164.   ['getConfiguration', 'configure'],
  165. ];
  168. /**
  169.  * Player getter and setter methods that are used to transfer state after
  170.  * load() is resolved.
  171.  * @const {!Array.<!Array.<string>>}
  172.  */
  173. shaka.cast.CastUtils.PlayerInitAfterLoadState = [
  174.   ['isTextTrackVisible', 'setTextTrackVisibility'],
  175. ];
  178. /**
  179.  * Player methods with no return value that are proxied while casting.
  180.  * @const {!Array.<string>}
  181.  */
  182. shaka.cast.CastUtils.PlayerVoidMethods = [
  183.   'addTextTrack',
  184.   'cancelTrickPlay',
  185.   'configure',
  186.   'resetConfiguration',
  187.   'retryStreaming',
  188.   'selectAudioLanguage',
  189.   'selectEmbeddedTextTrack',
  190.   'selectTextLanguage',
  191.   'selectTextTrack',
  192.   'selectVariantTrack',
  193.   'setTextTrackVisibility',
  194.   'trickPlay',
  195. ];
  198. /**
  199.  * Player methods returning a Promise that are proxied while casting.
  200.  * @const {!Array.<string>}
  201.  */
  202. shaka.cast.CastUtils.PlayerPromiseMethods = [
  203.   'attach',
  204.   'detach',
  205.   // The manifestFactory parameter of load is not supported.
  206.   'load',
  207.   'unload',
  208. ];
  211. /**
  212.  * @typedef {{
  213.  *   video: Object,
  214.  *   player: Object,
  215.  *   manifest: ?string,
  216.  *   startTime: ?number
  217.  * }}
  218.  * @property {Object} video
  219.  *   Dictionary of video properties to be set.
  220.  * @property {Object} player
  221.  *   Dictionary of player setters to be called.
  222.  * @property {?string} manifest
  223.  *   The currently-selected manifest, if present.
  224.  * @property {?number} startTime
  225.  *   The playback start time, if currently playing.
  226.  */
  227. shaka.cast.CastUtils.InitStateType;
  230. /**
  231.  * The namespace for Shaka messages on the cast bus.
  232.  * @const {string}
  233.  */
  234. shaka.cast.CastUtils.SHAKA_MESSAGE_NAMESPACE = 'urn:x-cast:com.google.shaka.v2';
  237. /**
  238.  * The namespace for generic messages on the cast bus.
  239.  * @const {string}
  240.  */
  241. shaka.cast.CastUtils.GENERIC_MESSAGE_NAMESPACE =
  242.     'urn:x-cast:com.google.cast.media';
  245. /**
  246.  * Serialize as JSON, but specially encode things JSON will not otherwise
  247.  * represent.
  248.  * @param {?} thing
  249.  * @return {string}
  250.  */
  251. shaka.cast.CastUtils.serialize = function(thing) {
  252.   return JSON.stringify(thing, function(key, value) {
  253.     if (typeof value == 'function') {
  254.       // Functions can't be (safely) serialized.
  255.       return undefined;
  256.     }
  258.     if (value instanceof Event || value instanceof shaka.util.FakeEvent) {
  259.       // Events don't serialize to JSON well because of the DOM objects
  260.       // and other complex objects they contain, so we strip these out.
  261.       // Note that using Object.keys or JSON.stringify directly on the event
  262.       // will not capture its properties.  We must use a for loop.
  263.       let simpleEvent = {};
  264.       for (let eventKey in value) {
  265.         let eventValue = value[eventKey];
  266.         if (eventValue && typeof eventValue == 'object') {
  267.           if (eventKey == 'detail') {
  268.             // Keep the detail value, because it contains important information
  269.             // for diagnosing errors.
  270.             simpleEvent[eventKey] = eventValue;
  271.           }
  272.           // Strip out non-null object types because they are complex and we
  273.           // don't need them.
  274.         } else if (eventKey in Event) {
  275.           // Strip out keys that are found on Event itself because they are
  276.           // class-level constants we don't need, like Event.MOUSEMOVE == 16.
  277.         } else {
  278.           simpleEvent[eventKey] = eventValue;
  279.         }
  280.       }
  281.       return simpleEvent;
  282.     }
  284.     if (value instanceof TimeRanges) {
  285.       // TimeRanges must be unpacked into plain data for serialization.
  286.       return shaka.cast.CastUtils.unpackTimeRanges_(value);
  287.     }
  289.     if (typeof value == 'number') {
  290.       // NaN and infinity cannot be represented directly in JSON.
  291.       if (isNaN(value)) return 'NaN';
  292.       if (isFinite(value)) return value;
  293.       if (value < 0) return '-Infinity';
  294.       return 'Infinity';
  295.     }
  297.     return value;
  298.   });
  299. };
  302. /**
  303.  * Deserialize JSON using our special encodings.
  304.  * @param {string} str
  305.  * @return {?}
  306.  */
  307. shaka.cast.CastUtils.deserialize = function(str) {
  308.   return JSON.parse(str, function(key, value) {
  309.     if (value == 'NaN') {
  310.       return NaN;
  311.     } else if (value == '-Infinity') {
  312.       return -Infinity;
  313.     } else if (value == 'Infinity') {
  314.       return Infinity;
  315.     } else if (value && typeof value == 'object' &&
  316.                value['__type__'] == 'TimeRanges') {
  317.       // TimeRanges objects have been unpacked and sent as plain data.
  318.       // Simulate the original TimeRanges object.
  319.       return shaka.cast.CastUtils.simulateTimeRanges_(value);
  320.     }
  321.     return value;
  322.   });
  323. };
  326. /**
  327.  * @param {!TimeRanges} ranges
  328.  * @return {Object}
  329.  * @private
  330.  */
  331. shaka.cast.CastUtils.unpackTimeRanges_ = function(ranges) {
  332.   let obj = {
  333.     '__type__': 'TimeRanges',  // a signal to deserialize
  334.     'length': ranges.length,
  335.     'start': [],
  336.     'end': [],
  337.   };
  339.   for (let i = 0; i < ranges.length; ++i) {
  340.     obj['start'].push(ranges.start(i));
  341.     obj['end'].push(ranges.end(i));
  342.   }
  344.   return obj;
  345. };
  348. /**
  349.  * Creates a simulated TimeRanges object from data sent by the cast receiver.
  350.  * @param {?} obj
  351.  * @return {{
  352.  *   length: number,
  353.  *   start: function(number): number,
  354.  *   end: function(number): number
  355.  * }}
  356.  * @private
  357.  */
  358. shaka.cast.CastUtils.simulateTimeRanges_ = function(obj) {
  359.   return {
  360.     length: obj.length,
  361.     // NOTE: a more complete simulation would throw when |i| was out of range,
  362.     // but for simplicity we will assume a well-behaved application that uses
  363.     // length instead of catch to stop iterating.
  364.     start: function(i) { return obj.start[i]; },
  365.     end: function(i) { return obj.end[i]; },
  366.   };
  367. };