chrome/browser/resources/chromeos/chromevox/host/interface/abstract_host.js

   1 // Copyright 2014 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 Abstract interface to methods that differ depending on the
   7  * host platform.
   8  *
   9  */
  10
  11 goog.provide('cvox.AbstractHost');
  12
  13
  14 /**
  15  * @constructor
  16  */
  17 cvox.AbstractHost = function() {
  18 };
  19
  20
  21 /**
  22  * @enum {number}
  23  */
  24 cvox.AbstractHost.State = {
  25   ACTIVE: 0,
  26   INACTIVE: 1,
  27   KILLED: 2
  28 };
  29
  30
  31 /**
  32  * Do all host-platform-specific initialization.
  33  */
  34 cvox.AbstractHost.prototype.init = function() {
  35 };
  36
  37
  38 /**
  39  * Used to reinitialize ChromeVox if initialization fails.
  40  */
  41 cvox.AbstractHost.prototype.reinit = function() {
  42 };
  43
  44
  45 /**
  46  * Executed on page load.
  47  */
  48 cvox.AbstractHost.prototype.onPageLoad = function() {
  49 };
  50
  51
  52 /**
  53  * Sends a message to the background page (if it exists) for this host.
  54  * @param {Object} message The message to pass to the background page.
  55  */
  56 cvox.AbstractHost.prototype.sendToBackgroundPage = function(message) {
  57 };
  58
  59
  60 /**
  61  * Returns the absolute URL to the API source.
  62  * @return {string} The URL.
  63  */
  64 cvox.AbstractHost.prototype.getApiSrc = function() {
  65   return '';
  66 };
  67
  68
  69 /**
  70  * Return the absolute URL to the given file.
  71  * @param {string} path The URL suffix.
  72  * @return {string} The full URL.
  73  */
  74 cvox.AbstractHost.prototype.getFileSrc = function(path) {
  75   return '';
  76 };
  77
  78
  79 /**
  80  * @return {boolean} True if the host has a Tts callback.
  81  */
  82 cvox.AbstractHost.prototype.hasTtsCallback = function() {
  83   return true;
  84 };
  85
  86
  87 /**
  88  * @return {boolean} True if the TTS has been loaded.
  89  */
  90 cvox.AbstractHost.prototype.ttsLoaded = function() {
  91   return true;
  92 };
  93
  94
  95 /**
  96  * @return {boolean} True if the ChromeVox is supposed to intercept and handle
  97  * mouse clicks for the platform, instead of just letting the clicks fall
  98  * through.
  99  *
 100  * Note: This behavior is only needed for Android because of the way touch
 101  * exploration and double-tap to click is implemented by the platform.
 102  */
 103 cvox.AbstractHost.prototype.mustRedispatchClickEvent = function() {
 104   return false;
 105 };
 106
 107 /**
 108  * Activate or deactivate ChromeVox on this host.
 109  * @param {boolean} active The desired state; true for active, false for
 110  * inactive.
 111  */
 112 cvox.AbstractHost.prototype.activateOrDeactivateChromeVox = function(active) {
 113   this.onStateChanged_(active ? cvox.AbstractHost.State.ACTIVE :
 114       cvox.AbstractHost.State.INACTIVE);
 115 };
 116
 117
 118 /**
 119  * Kills ChromeVox on this host.
 120  */
 121 cvox.AbstractHost.prototype.killChromeVox = function() {
 122   this.onStateChanged_(cvox.AbstractHost.State.KILLED);
 123 };
 124
 125
 126 /**
 127  * Helper managing the three states of ChromeVox --
 128  * active: all event listeners registered
 129  * inactive: only key down listener registered
 130  * killed: no listeners registered
 131  * @param {cvox.AbstractHost.State} state The new state.
 132  * @private
 133  */
 134 cvox.AbstractHost.prototype.onStateChanged_ = function(state) {
 135   var active = state == cvox.AbstractHost.State.ACTIVE;
 136   if (active == cvox.ChromeVox.isActive) {
 137     return;
 138   }
 139   cvox.ChromeVoxEventWatcher.cleanup(window);
 140   switch (state) {
 141     case cvox.AbstractHost.State.ACTIVE:
 142       cvox.ChromeVox.isActive = true;
 143       cvox.ChromeVox.navigationManager.showOrHideIndicator(true);
 144       cvox.ChromeVoxEventWatcher.init(window);
 145       if (document.activeElement) {
 146         var speakNodeAlso = cvox.ChromeVox.documentHasFocus();
 147         cvox.ApiImplementation.syncToNode(
 148             document.activeElement, speakNodeAlso);
 149       } else {
 150         cvox.ChromeVox.navigationManager.updateIndicator();
 151       }
 152       break;
 153     case cvox.AbstractHost.State.INACTIVE:
 154       cvox.ChromeVox.isActive = false;
 155       cvox.ChromeVox.navigationManager.showOrHideIndicator(false);
 156       // If ChromeVox is inactive, the event watcher will only listen for key
 157       // down events.
 158       cvox.ChromeVoxEventWatcher.init(window);
 159       break;
 160     case cvox.AbstractHost.State.KILLED:
 161       cvox.ChromeVox.isActive = false;
 162       cvox.ChromeVox.navigationManager.showOrHideIndicator(false);
 163       break;
 164   }
 165 };