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

chrome/browser/resources/access_chromevox/chromevox/injected/keyboard_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.
+
+goog.provide('cvox.ChromeVoxKbHandler');
+
+goog.require('cvox.ChromeVox');
+goog.require('cvox.ChromeVoxJSON');
+goog.require('cvox.ChromeVoxSearch');
+goog.require('cvox.ChromeVoxUserCommands');
+goog.require('cvox.KeyUtil');
+
+/**
+ * @fileoverview Handles user keyboard input events.
+ */
+cvox.ChromeVoxKbHandler = {};
+
+/**
+ * Maps a key string in the form generated by KeyUtil.keyEventToString
+ * (like "Ctrl+Alt+X") into the name of a command to execute.
+ *
+ * @type {Object}
+ */
+cvox.ChromeVoxKbHandler.keyToFunctionsTable = {};
+
+/**
+ * Loads the key bindings into the keyToFunctionsTable.
+ *
+ *  @param {Object} keyToFunctionsTable The key bindings table.
+ */
+cvox.ChromeVoxKbHandler.loadKeyToFunctionsTable = function(
+    keyToFunctionsTable) {
+  console.log('Got keyToFunctionsTable: ' +
+      JSON.stringify(keyToFunctionsTable));
+  cvox.ChromeVoxKbHandler.keyToFunctionsTable = keyToFunctionsTable;
+};
+
+/**
+ * Checks if ChromeVox must pass the enter key to the browser.
+ * For example, if the user has focus on an input field, link, button,
+ * etc., then that takes precedence over anything else ChromeVox
+ * might be doing and so it must pass the enter key to the browser.
+ *
+ * @return {boolean} True if an Enter key event must be passed to the browser.
+ */
+cvox.ChromeVoxKbHandler.mustPassEnterKey = function() {
+  return (document.activeElement &&
+      ((document.activeElement.tagName == 'INPUT') ||
+       (document.activeElement.tagName == 'A') ||
+       (document.activeElement.tagName == 'SELECT') ||
+       (document.activeElement.tagName == 'BUTTON') ||
+       (document.activeElement.tagName == 'TEXTAREA')));
+};
+
+/**
+ * Handles key down events.
+ *
+ * @param {Object} evt The key down event to process.
+ * @return {boolean} True if the default action should be performed.
+ */
+cvox.ChromeVoxKbHandler.basicKeyDownActionsListener = function(evt) {
+  // The enter key can be handled either by ChromeVox or by the browser.
+  if (evt.keyCode == 13) {
+    // If the user is focused on something that explicitly takes the
+    // enter key, that has precedence. Always let the key through.
+    if (cvox.ChromeVoxKbHandler.mustPassEnterKey()) {
+      return true;
+    }
+    // The only time ChromeVox should consider handling the enter
+    // key is if the navigation manager is able to act on the current item.
+    if (!cvox.ChromeVox.navigationManager.canActOnCurrentItem()) {
+      return true;
+    }
+  }
+
+  var keyStr = cvox.KeyUtil.keyEventToString(evt);
+  var functionName = cvox.ChromeVoxKbHandler.keyToFunctionsTable[keyStr];
+  var func = cvox.ChromeVoxUserCommands.commands[functionName];
+
+  if (func) {
+    if (cvox.ChromeVoxSearch.isActive()) {
+      cvox.ChromeVoxSearch.hide();
+      cvox.ChromeVox.navigationManager.syncToSelection();
+    }
+    return func();
+  }
+
+  return true;
+};