chrome/browser/resources/app_list/speech_recognition_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 speech recognition.
   7  */
   8
   9 cr.define('speech', function() {
  10   'use strict';
  11
  12   /**
  13    * @constructor
  14    */
  15   function SpeechRecognitionManager(delegate) {
  16     this.isActive = true;
  17     this.delegate_ = delegate;
  18
  19     this.recognizer_ = new window.webkitSpeechRecognition();
  20     this.recognizer_.continuous = true;
  21     this.recognizer_.interimResults = true;
  22     this.recognizer_.lang = navigator.language;
  23
  24     this.recognizer_.onresult = this.onRecognizerResult_.bind(this);
  25     if (this.delegate_) {
  26       this.recognizer_.onstart =
  27           this.delegate_.onSpeechRecognitionStarted.bind(this.delegate_);
  28       this.recognizer_.onend =
  29           this.delegate_.onSpeechRecognitionEnded.bind(this.delegate_);
  30       this.recognizer_.onspeechstart =
  31           this.delegate_.onSpeechStarted.bind(this.delegate_);
  32       this.recognizer_.onspeechend =
  33           this.delegate_.onSpeechEnded.bind(this.delegate_);
  34       this.recognizer_.onerror = this.onRecognizerError_.bind(this);
  35     }
  36   }
  37
  38   /**
  39    * Called when new speech recognition results arrive.
  40    *
  41    * @param {Event} speechEvent The event to contain the recognition results.
  42    * @private
  43    */
  44   SpeechRecognitionManager.prototype.onRecognizerResult_ = function(
  45       speechEvent) {
  46     // Do not collect interim result for now.
  47     var result = '';
  48     var isFinal = false;
  49     for (var i = 0; i < speechEvent.results.length; i++) {
  50       if (speechEvent.results[i].isFinal)
  51         isFinal = true;
  52       result += speechEvent.results[i][0].transcript;
  53     }
  54     if (this.delegate_)
  55       this.delegate_.onSpeechRecognized(result, isFinal);
  56   };
  57
  58   /**
  59    * Called when an error happens in speech recognition.
  60    *
  61    * @param {SpeechRecognitionError} error The error data.
  62    * @private
  63    */
  64   SpeechRecognitionManager.prototype.onRecognizerError_ = function(error) {
  65     if (error.error == 'language-not-supported') {
  66       // Falls back to English and restart.
  67       this.recognizer_.lang = 'en-US';
  68       this.start();
  69     } else {
  70       this.delegate_.onSpeechRecognitionError(error);
  71     }
  72   };
  73
  74   /**
  75    * Starts the speech recognition through webkitSpeechRecognition.
  76    */
  77   SpeechRecognitionManager.prototype.start = function() {
  78     this.recognizer_.start();
  79   };
  80
  81   /**
  82    * Stops the ongoing speech recognition.
  83    */
  84   SpeechRecognitionManager.prototype.stop = function() {
  85     this.recognizer_.abort();
  86   };
  87
  88   return {
  89     SpeechRecognitionManager: SpeechRecognitionManager
  90   };
  91 });