chrome/browser/resources/app_list/plugin_manager.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 The manager of offline hotword speech recognizer plugin.
   7  */
   8
   9 cr.define('speech', function() {
  10   'use strict';
  11
  12   /**
  13    * The type of the plugin state.
  14    ** @enum {number}
  15    */
  16   var PluginState = {
  17     UNINITIALIZED: 0,
  18     LOADED: 1,
  19     SAMPLING_RATE_READY: 2,
  20     READY: 3,
  21     RECOGNIZING: 4
  22   };
  23
  24   /**
  25    * The command names of the plugin.
  26    * @enum {string}
  27    */
  28   var pluginCommands = {
  29     SET_SAMPLING_RATE: 'h',
  30     SET_CONFIG: 'm',
  31     START_RECOGNIZING: 'r',
  32     STOP_RECOGNIZING: 's'
  33   };
  34
  35   /**
  36    * The regexp pattern of the hotword recognition result.
  37    */
  38   var recognitionPattern = /^HotwordFiredEvent: \[(.*)\] confidence: (.*)/;
  39
  40   /**
  41    * Checks the availability of the plugin.
  42    * @return {boolean} True only if the plugin is available.
  43    */
  44   function isPluginAvailable() {
  45     return !!($('recognizer') && $('recognizer').postMessage);
  46   }
  47
  48   /**
  49    * @constructor
  50    */
  51   function PluginManager(onReady, onRecognized) {
  52     this.state = PluginState.UNINITIALIZED;
  53     this.onReady_ = onReady;
  54     this.onRecognized_ = onRecognized;
  55     this.samplingRate_ = null;
  56     this.config_ = null;
  57     if (isPluginAvailable()) {
  58       $('recognizer').addEventListener('message', this.onMessage_.bind(this));
  59       $('recognizer').addEventListener('load', this.onLoad_.bind(this));
  60     }
  61   };
  62
  63   /**
  64    * The event handler of the plugin status.
  65    *
  66    * @param {Event} messageEvent the event object from the plugin.
  67    * @private
  68    */
  69   PluginManager.prototype.onMessage_ = function(messageEvent) {
  70     if (this.state == PluginState.LOADED) {
  71       if (messageEvent.data == 'stopped')
  72         this.state = PluginState.SAMPLING_RATE_READY;
  73       return;
  74     }
  75
  76     if (messageEvent.data == 'audio') {
  77       if (this.state < PluginState.READY)
  78         this.onReady_(this);
  79       this.state = PluginState.RECOGNIZING;
  80     } else if (messageEvent.data == 'stopped') {
  81       this.state = PluginState.READY;
  82     } else {
  83       var matched = recognitionPattern.exec(messageEvent.data);
  84       if (matched && matched[1] == 'hotword_ok_google')
  85         this.onRecognized_(Number(matched[2]));
  86     }
  87   };
  88
  89   /**
  90    * The event handler when the plugin is loaded.
  91    *
  92    * @private
  93    */
  94   PluginManager.prototype.onLoad_ = function() {
  95     if (this.state == PluginState.UNINITIALIZED) {
  96       this.state = PluginState.LOADED;
  97       if (this.samplingRate_ && this.config_)
  98         this.initialize_(this.samplingRate_, this.config_);
  99     }
 100   };
 101
 102   /**
 103    * Sends the initialization messages to the plugin. This method is private.
 104    * The initialization will happen from onLoad_ or scheduleInitialize.
 105    *
 106    * @param {number} samplingRate the sampling rate the plugin accepts.
 107    * @param {string} config the url of the config file.
 108    * @private
 109    */
 110   PluginManager.prototype.initialize_ = function(samplingRate, config) {
 111     $('recognizer').postMessage(
 112         pluginCommands.SET_SAMPLING_RATE + samplingRate);
 113     $('recognizer').postMessage(pluginCommands.SET_CONFIG + config);
 114   };
 115
 116   /**
 117    * Initializes the plugin with the specified parameter, or schedules the
 118    * initialization if the plugin is not ready.
 119    *
 120    * @param {number} samplingRate the sampling rate the plugin accepts.
 121    * @param {string} config the url of the config file.
 122    */
 123   PluginManager.prototype.scheduleInitialize = function(samplingRate, config) {
 124     if (this.state == PluginState.UNINITIALIZED) {
 125       this.samplingRate_ = samplingRate;
 126       this.config_ = config;
 127     } else {
 128       this.initialize_(samplingRate, config);
 129     }
 130   };
 131
 132   /**
 133    * Asks the plugin to start recognizing the hotword.
 134    */
 135   PluginManager.prototype.startRecognizer = function() {
 136     if (this.state == PluginState.READY)
 137       $('recognizer').postMessage(pluginCommands.START_RECOGNIZING);
 138   };
 139
 140   /**
 141    * Asks the plugin to stop recognizing the hotword.
 142    */
 143   PluginManager.prototype.stopRecognizer = function() {
 144     if (this.state == PluginState.RECOGNIZING)
 145       $('recognizer').postMessage(pluginCommands.STOP_RECOGNIZING);
 146   };
 147
 148   /**
 149    * Sends the actual audio wave data.
 150    *
 151    * @param {cr.event.Event} event The event for the audio data.
 152    */
 153   PluginManager.prototype.sendAudioData = function(event) {
 154     if (this.state == PluginState.RECOGNIZING)
 155       $('recognizer').postMessage(event.data.buffer);
 156   };
 157
 158   return {
 159     PluginManager: PluginManager,
 160     PluginState: PluginState,
 161     isPluginAvailable: isPluginAvailable
 162   };
 163 });