Adding ChromeVox as a component extensions (enabled only for ChromeOS, for no...

chrome/browser/resources/access_chromevox/chromevox/background/accessibility_api_handler.js

+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+/**
+ * @fileoverview Accesses Chrome's accessibility extension API and gives
+ * spoken feedback for events that happen in the "Chrome of Chrome".
+ */
+
+goog.provide('cvox.ChromeVoxAccessibilityApiHandler');
+
+goog.require('cvox.AbstractEarcons');
+goog.require('cvox.AbstractEarconsManager');
+goog.require('cvox.AbstractTtsManager');
+goog.require('cvox.ChromeVoxEditableTextBase');
+
+/**
+ * Class that adds listeners and handles events from the accessibility API.
+ */
+cvox.ChromeVoxAccessibilityApiHandler = function() {
+};
+
+/**
+ * The object used to play earcons.
+ * @type Object
+ */
+cvox.ChromeVoxAccessibilityApiHandler.ttsManager = null;
+
+/**
+ * The object used to manage speech.
+ * @type Object
+ */
+cvox.ChromeVoxAccessibilityApiHandler.earconsManager = null;
+
+/**
+ * The object that can describe changes and cursor movement in a generic
+ *     editable text field.
+ * @type Object
+ */
+cvox.ChromeVoxAccessibilityApiHandler.editableTextHandler = null;
+
+/**
+ * Initialize the accessibility API Handler.
+ * @param {Object} ttsManager The TTS manager to use for speaking.
+ * @param {Object} earconsManager The earcons manager to use for playing
+ *        earcons.
+ */
+cvox.ChromeVoxAccessibilityApiHandler.init = function(ttsManager,
+    earconsManager) {
+  cvox.ChromeVoxAccessibilityApiHandler.ttsManager = ttsManager;
+  cvox.ChromeVoxAccessibilityApiHandler.earconsManager = earconsManager;
+  try {
+    chrome.experimental.accessibility.setAccessibilityEnabled(true);
+    cvox.ChromeVoxAccessibilityApiHandler.addEventListeners();
+  } catch (err) {
+    console.log('Error trying to access accessibility extension api.');
+  }
+};
+
+/**
+ * Adds event listeners.
+ */
+cvox.ChromeVoxAccessibilityApiHandler.addEventListeners = function() {
+  var accessibility = chrome.experimental.accessibility;
+
+  chrome.tabs.onCreated.addListener(function(tab) {
+    var tts = cvox.ChromeVoxAccessibilityApiHandler.ttsManager;
+    var title = tab.title ? tab.title : tab.url;
+    tts.speak(title + ', tab created.', 0, {});
+    var earcons = cvox.ChromeVoxAccessibilityApiHandler.earconsManager;
+    earcons.playEarcon(cvox.AbstractEarcons.OBJECT_OPEN);
+  });
+
+  chrome.tabs.onRemoved.addListener(function(tab) {
+    var earcons = cvox.ChromeVoxAccessibilityApiHandler.earconsManager;
+    earcons.playEarcon(cvox.AbstractEarcons.OBJECT_CLOSE);
+  });
+
+  chrome.tabs.onSelectionChanged.addListener(function(tabId, selectInfo) {
+    chrome.tabs.get(tabId, function(tab) {
+      var tts = cvox.ChromeVoxAccessibilityApiHandler.ttsManager;
+      var title = tab.title ? tab.title : tab.url;
+      tts.speak(title + ', tab.', 0, {});
+      var earcons = cvox.ChromeVoxAccessibilityApiHandler.earconsManager;
+      earcons.playEarcon(cvox.AbstractEarcons.OBJECT_SELECT);
+    });
+  });
+
+  chrome.tabs.onUpdated.addListener(function(tabId, selectInfo) {
+    chrome.tabs.get(tabId, function(tab) {
+      var earcons = cvox.ChromeVoxAccessibilityApiHandler.earconsManager;
+      if (tab.status == 'loading') {
+        earcons.playEarcon(cvox.AbstractEarcons.BUSY_PROGRESS_LOOP);
+      } else {
+        earcons.playEarcon(cvox.AbstractEarcons.TASK_SUCCESS);
+      }
+    });
+  });
+
+  chrome.experimental.accessibility.onWindowOpened.addListener(function(win) {
+    var tts = cvox.ChromeVoxAccessibilityApiHandler.ttsManager;
+    tts.speak(win.name + ', window opened.', 0, {});
+    var earcons = cvox.ChromeVoxAccessibilityApiHandler.earconsManager;
+    earcons.playEarcon(cvox.AbstractEarcons.OBJECT_OPEN);
+  });
+
+  chrome.experimental.accessibility.onWindowClosed.addListener(function(win) {
+    var tts = cvox.ChromeVoxAccessibilityApiHandler.ttsManager;
+    tts.speak(win.name + ', window closed.', 0, {});
+    var earcons = cvox.ChromeVoxAccessibilityApiHandler.earconsManager;
+    earcons.playEarcon(cvox.AbstractEarcons.OBJECT_CLOSE);
+  });
+
+  chrome.experimental.accessibility.onMenuOpened.addListener(function(menu) {
+    var tts = cvox.ChromeVoxAccessibilityApiHandler.ttsManager;
+    tts.speak(menu.name + ', menu opened.', 0, {});
+    var earcons = cvox.ChromeVoxAccessibilityApiHandler.earconsManager;
+    earcons.playEarcon(cvox.AbstractEarcons.OBJECT_OPEN);
+  });
+
+  chrome.experimental.accessibility.onMenuClosed.addListener(function(menu) {
+    var tts = cvox.ChromeVoxAccessibilityApiHandler.ttsManager;
+    tts.speak(menu.name + ', menu closed.', 0, {});
+    var earcons = cvox.ChromeVoxAccessibilityApiHandler.earconsManager;
+    earcons.playEarcon(cvox.AbstractEarcons.OBJECT_CLOSE);
+  });
+
+  chrome.experimental.accessibility.onControlFocused.addListener(
+    /**
+     * @param {AccessibilityObject} ctl The focused control.
+     */
+    function(ctl) {
+      var tts = cvox.ChromeVoxAccessibilityApiHandler.ttsManager;
+      if (ctl.type == 'textbox') {
+        cvox.ChromeVoxAccessibilityApiHandler.trimWhitespace(ctl);
+        cvox.ChromeVoxAccessibilityApiHandler.editableTextHandler =
+            new cvox.ChromeVoxEditableTextBase(
+                ctl.details.value,
+                ctl.details.selectionStart,
+                ctl.details.selectionEnd,
+                tts);
+      } else {
+        cvox.ChromeVoxAccessibilityApiHandler.editableTextHandler = null;
+      }
+
+      var description = cvox.ChromeVoxAccessibilityApiHandler.describe(ctl,
+          false);
+      tts.speak(description.utterance, 0, {});
+      if (description.earcon) {
+          var earcons =
+              cvox.ChromeVoxAccessibilityApiHandler.earconsManager;
+          earcons.playEarcon(description.earcon);
+      }
+    });
+
+  chrome.experimental.accessibility.onControlAction.addListener(function(ctl) {
+    var tts = cvox.ChromeVoxAccessibilityApiHandler.ttsManager;
+    var description = cvox.ChromeVoxAccessibilityApiHandler.describe(ctl,
+        true);
+    tts.speak(description.utterance, 0, {});
+    if (description.earcon) {
+      var earcons = cvox.ChromeVoxAccessibilityApiHandler.earconsManager;
+      earcons.playEarcon(description.earcon);
+    }
+  });
+
+  chrome.experimental.accessibility.onTextChanged.addListener(function(ctl) {
+    if (cvox.ChromeVoxAccessibilityApiHandler.editableTextHandler) {
+      cvox.ChromeVoxAccessibilityApiHandler.trimWhitespace(ctl);
+      cvox.ChromeVoxAccessibilityApiHandler.editableTextHandler.changed(
+          ctl.details.value,
+          ctl.details.selectionStart,
+          ctl.details.selectionEnd);
+    }
+  });
+};
+
+/**
+ * Given a text control received from the accessibility api, trim any
+ * leading or trailing whitespace from control.details.value and from
+ * selectionStart and selectionEnd.
+ * @param {Object} control The text control object.
+ */
+cvox.ChromeVoxAccessibilityApiHandler.trimWhitespace = function(control) {
+  var d = control.details;
+  var prefix = new RegExp(/^[\s\u200b]+/).exec(d.value);
+  var suffix = new RegExp(/[\s\u200b]+$/).exec(d.value);
+  var prefixLen = prefix ? prefix.length : 0;
+  var suffixLen = suffix ? suffix.length : 0;
+  d.value = d.value.substr(prefix, d.value.length - prefixLen - suffixLen);
+  d.selectionStart -= prefixLen;
+  d.selectionEnd -= prefixLen;
+  if (d.selectionEnd > d.value.length) {
+    d.selectionEnd = d.value.length;
+  }
+};
+
+/**
+ * Given a control received from the accessibility api, determine an
+ * utterance to speak and an earcon to play to describe it.
+ * @param {Object} control The control that had an action performed on it.
+ * @param {boolean} isSelect True if the action is a select action,
+ *     otherwise it's a focus action.
+ * @return {Object} An object containing a string field |utterance| and
+ *     earcon |earcon|.
+ */
+cvox.ChromeVoxAccessibilityApiHandler.describe = function(control,
+    isSelect) {
+  var s = '';
+  var earcon = undefined;
+  var name = control.name.replace(/[_&]+/g, '').replace('...', '');
+  switch (control.type) {
+    case 'checkbox':
+      s += name;
+      if (control.details.isChecked) {
+        earcon = cvox.AbstractEarcons.CHECK_ON;
+        s += ', checkbox checked';
+      } else {
+        earcon = cvox.AbstractEarcons.CHECK_OFF;
+        s += ', checkbox not checked';
+      }
+      break;
+    case 'radiobutton':
+      s += name;
+      if (control.details.isChecked) {
+        earcon = cvox.AbstractEarcons.CHECK_ON;
+        s += ', radio button selected';
+      } else {
+        earcon = cvox.AbstractEarcons.CHECK_OFF;
+        s += ', radio button unselected';
+      }
+      break;
+    case 'menu':
+      s += name + ', menu';
+      break;
+    case 'menuitem':
+      s += name + ', menu item';
+      if (control.details.hasSubmenu) {
+        s += ', with submenu';
+      }
+      break;
+    case 'window':
+      s += name + ', window';
+      break;
+    case 'textbox':
+      earcon = cvox.AbstractEarcons.EDITABLE_TEXT;
+      s += control.details.value;
+      if (name != '') {
+        s += ', ' + name;
+      }
+      s += ', text box';
+      break;
+    case 'button':
+      earcon = cvox.AbstractEarcons.BUTTON;
+      s += name + ', button';
+      break;
+    case 'combobox':
+      earcon = cvox.AbstractEarcons.LISTBOX;
+      s += control.details.value;
+      if (name != '') {
+        s += ', ' + name;
+      }
+      s += ', combo box';
+      break;
+    case 'listbox':
+      earcon = cvox.AbstractEarcons.LISTBOX;
+      s += control.details.value;
+      if (name != '') {
+        s += ', ' + name;
+      }
+      s += ', list box';
+      break;
+    case 'link':
+      earcon = cvox.AbstractEarcons.LINK;
+      s += name + ', link';
+      break;
+    case 'tab':
+      s += name + ', tab';
+      break;
+
+    default:
+      s += name + ', ' + control.type;
+  }
+
+  if (isSelect) {
+    s += ', selected';
+  }
+  try {
+    if (control.details.itemCount >= 0) {
+      s += ', ' + (control.details.itemIndex + 1) +
+          ' of ' + control.details.itemCount;
+    }
+  } catch (err) {
+  }
+
+  s += '.';
+
+  var description = {};
+  description.utterance = s;
+  description.earcon = earcon;
+  return description;
+};