content/browser/resources/media/player_info.js

   1 // Copyright 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 /**
   6  * @fileoverview A class for keeping track of the details of a player.
   7  */
   8
   9 var PlayerInfo = (function() {
  10   'use strict';
  11
  12   /**
  13    * A class that keeps track of properties on a media player.
  14    * @param id A unique id that can be used to identify this player.
  15    */
  16   function PlayerInfo(id) {
  17     this.id = id;
  18     // The current value of the properties for this player.
  19     this.properties = {};
  20     // All of the past (and present) values of the properties.
  21     this.pastValues = {};
  22
  23     // Every single event in the order in which they were received.
  24     this.allEvents = [];
  25     this.lastRendered = 0;
  26
  27     this.firstTimestamp_ = -1;
  28   }
  29
  30   PlayerInfo.prototype = {
  31     /**
  32      * Adds or set a property on this player.
  33      * This is the default logging method as it keeps track of old values.
  34      * @param timestamp  The time in milliseconds since the Epoch.
  35      * @param key A String key that describes the property.
  36      * @param value The value of the property.
  37      */
  38     addProperty: function(timestamp, key, value) {
  39       // The first timestamp that we get will be recorded.
  40       // Then, all future timestamps are deltas of that.
  41       if (this.firstTimestamp_ === -1) {
  42         this.firstTimestamp_ = timestamp;
  43       }
  44
  45       if (typeof key !== 'string') {
  46         throw new Error(typeof key + ' is not a valid key type');
  47       }
  48
  49       this.properties[key] = value;
  50
  51       if (!this.pastValues[key]) {
  52         this.pastValues[key] = [];
  53       }
  54
  55       var recordValue = {
  56         time: timestamp - this.firstTimestamp_,
  57         key: key,
  58         value: value
  59       };
  60
  61       this.pastValues[key].push(recordValue);
  62       this.allEvents.push(recordValue);
  63     },
  64
  65     /**
  66      * Adds or set a property on this player.
  67      * Does not keep track of old values.  This is better for
  68      * values that get spammed repeatedly.
  69      * @param timestamp The time in milliseconds since the Epoch.
  70      * @param key A String key that describes the property.
  71      * @param value The value of the property.
  72      */
  73     addPropertyNoRecord: function(timestamp, key, value) {
  74       this.addProperty(timestamp, key, value);
  75       this.allEvents.pop();
  76     }
  77   };
  78
  79   return PlayerInfo;
  80 }());