ui/accessibility/extensions/caretbrowsing/background.js

   1 // Copyright (c) 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 Script that runs on the background page.
   7  */
   8
   9 CONTENT_SCRIPTS = [
  10   'accessibility_utils.js',
  11   'traverse_util.js',
  12   'caret_browsing.js'
  13 ];
  14
  15 /**
  16  * The class handling the Caret Browsing background page, which keeps
  17  * track of the current state, handles the browser action button, and
  18  * initializes the content script in all running tabs when the extension
  19  * is first loaded.
  20  * @constructor
  21  */
  22 var CaretBkgnd = function() {};
  23
  24 /**
  25  * Flag indicating whether caret browsing is enabled. Global, applies to
  26  * all tabs simultaneously.
  27  * @type {boolean}
  28  */
  29 CaretBkgnd.isEnabled;
  30
  31 /**
  32  * Change the browser action icon and tooltip based on the enabled state.
  33  */
  34 CaretBkgnd.setIcon = function() {
  35   chrome.browserAction.setIcon(
  36       {'path': CaretBkgnd.isEnabled ?
  37                '../caret_19_on.png' :
  38                '../caret_19.png'});
  39   chrome.browserAction.setTitle(
  40       {'title': CaretBkgnd.isEnabled ?
  41                 'Turn Off Caret Browsing (F7)' :
  42                 'Turn On Caret Browsing (F7)' });
  43 };
  44
  45 /**
  46  * This is called when the extension is first loaded, so that it can be
  47  * immediately used in all already-open tabs. It's not needed for any
  48  * new tabs that open after that, the content script will be automatically
  49  * injected into any new tab.
  50  */
  51 CaretBkgnd.injectContentScripts = function() {
  52   chrome.windows.getAll({'populate': true}, function(windows) {
  53     for (var i = 0; i < windows.length; i++) {
  54       var tabs = windows[i].tabs;
  55       for (var j = 0; j < tabs.length; j++) {
  56         for (var k = 0; k < CONTENT_SCRIPTS.length; k++) {
  57           chrome.tabs.executeScript(
  58               tabs[j].id,
  59               {file: CONTENT_SCRIPTS[k], allFrames: true},
  60               function(result) {
  61                 // Ignore.
  62                 chrome.runtime.lastError;
  63               });
  64         }
  65       }
  66     }
  67   });
  68 };
  69
  70 /**
  71  * Toggle caret browsing on or off, and update the browser action icon and
  72  * all open tabs.
  73  */
  74 CaretBkgnd.toggle = function() {
  75   CaretBkgnd.isEnabled = !CaretBkgnd.isEnabled;
  76   var obj = {};
  77   obj['enabled'] = CaretBkgnd.isEnabled;
  78   chrome.storage.sync.set(obj);
  79   CaretBkgnd.setIcon();
  80 };
  81
  82 /**
  83  * Initialize the background script. Set the initial value of the flag
  84  * based on the saved preference in localStorage, update the browser action,
  85  * inject into running tabs, and then set up communication with content
  86  * scripts in tabs. Also check for prefs updates (from the options page)
  87  * and send them to content scripts.
  88  */
  89 CaretBkgnd.init = function() {
  90   chrome.storage.sync.get('enabled', function(result) {
  91     CaretBkgnd.isEnabled = result['enabled'];
  92     CaretBkgnd.setIcon();
  93     CaretBkgnd.injectContentScripts();
  94
  95     chrome.browserAction.onClicked.addListener(function(tab) {
  96       CaretBkgnd.toggle();
  97     });
  98   });
  99
 100   chrome.storage.onChanged.addListener(function() {
 101     chrome.storage.sync.get('enabled', function(result) {
 102       CaretBkgnd.isEnabled = result['enabled'];
 103       CaretBkgnd.setIcon();
 104     });
 105   });
 106 };
 107
 108 CaretBkgnd.init();