chrome/browser/resources/chromeos/chromevox/extensions/searchvox/util.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 /**
   7  * @fileoverview Helper functions.
   8  */
   9
  10 goog.provide('cvox.SearchUtil');
  11
  12 /** Utility functions. */
  13 cvox.SearchUtil = function() {
  14 };
  15
  16 /**
  17  * Extracts the first URL from an element.
  18  * @param {Node} node DOM element to extract from.
  19  * @return {?string} URL.
  20  */
  21 cvox.SearchUtil.extractURL = function(node) {
  22   if (node) {
  23     if (node.tagName === 'A') {
  24       return node.href;
  25     }
  26     var anchor = node.querySelector('a');
  27     if (anchor) {
  28       return anchor.href;
  29     }
  30   }
  31   return null;
  32 };
  33
  34 /**
  35  * Indicates whether or not the search widget has been activated.
  36  * @return {boolean} Whether or not the search widget is active.
  37  */
  38 cvox.SearchUtil.isSearchWidgetActive = function() {
  39   var SEARCH_WIDGET_SELECT = '#cvox-search';
  40   return document.querySelector(SEARCH_WIDGET_SELECT) !== null;
  41 };
  42
  43 /**
  44  * Adds one to and index with wrapping.
  45  * @param {number} index Index to add to.
  46  * @param {number} length Length to wrap at.
  47  * @return {number} The new index++, wrapped if exceeding length.
  48  */
  49 cvox.SearchUtil.addOneWrap = function(index, length) {
  50   return (index + 1) % length;
  51 };
  52
  53 /**
  54  * Subtracts one to and index with wrapping.
  55  * @param {number} index Index to subtract from.
  56  * @param {number} length Length to wrap at.
  57  * @return {number} The new index--, wrapped if below 0.
  58  */
  59 cvox.SearchUtil.subOneWrap = function(index, length) {
  60   return (index - 1 + length) % length;
  61 };
  62
  63 /**
  64  * Returns the id of a node's active descendant
  65  * @param {Node} targetNode The node.
  66  * @return {?string} The id of the active descendant.
  67  * @private
  68  */
  69 var getActiveDescendantId_ = function(targetNode) {
  70   if (!targetNode.getAttribute) {
  71     return null;
  72   }
  73
  74   var activeId = targetNode.getAttribute('aria-activedescendant');
  75   if (!activeId) {
  76     return null;
  77   }
  78   return activeId;
  79 };
  80
  81 /**
  82  * If the node is an object with an active descendant, returns the
  83  * descendant node.
  84  *
  85  * This function will fully resolve an active descendant chain. If a circular
  86  * chain is detected, it will return null.
  87  *
  88  * @param {Node} targetNode The node to get descendant information for.
  89  * @return {Node} The descendant node or null if no node exists.
  90  */
  91 var getActiveDescendant = function(targetNode) {
  92   var seenIds = {};
  93   var node = targetNode;
  94
  95   while (node) {
  96     var activeId = getActiveDescendantId_(node);
  97     if (!activeId) {
  98       break;
  99     }
 100     if (activeId in seenIds) {
 101       // A circlar activeDescendant is an error, so return null.
 102       return null;
 103     }
 104     seenIds[activeId] = true;
 105     node = document.getElementById(activeId);
 106   }
 107
 108   if (node == targetNode) {
 109     return null;
 110   }
 111   return node;
 112 };
 113
 114 /**
 115  * Dispatches a left click event on the element that is the targetNode.
 116  * Clicks go in the sequence of mousedown, mouseup, and click.
 117  * @param {Node} targetNode The target node of this operation.
 118  * @param {boolean=} shiftKey Specifies if shift is held down.
 119  * @param {boolean=} callOnClickDirectly Specifies whether or not to directly
 120  * invoke the onclick method if there is one.
 121  * @param {boolean=} opt_double True to issue a double click.
 122  */
 123 cvox.SearchUtil.clickElem = function(
 124     targetNode, shiftKey, callOnClickDirectly, opt_double) {
 125   // If there is an activeDescendant of the targetNode, then that is where the
 126   // click should actually be targeted.
 127   var activeDescendant = getActiveDescendant(targetNode);
 128   if (activeDescendant) {
 129     targetNode = activeDescendant;
 130   }
 131   if (callOnClickDirectly) {
 132     var onClickFunction = null;
 133     if (targetNode.onclick) {
 134       onClickFunction = targetNode.onclick;
 135     }
 136     if (!onClickFunction && (targetNode.nodeType != 1) &&
 137         targetNode.parentNode && targetNode.parentNode.onclick) {
 138       onClickFunction = targetNode.parentNode.onclick;
 139     }
 140     var keepGoing = true;
 141     if (onClickFunction) {
 142       try {
 143         keepGoing = onClickFunction();
 144       } catch (exception) {
 145         // Something went very wrong with the onclick method; we'll ignore it
 146         // and just dispatch a click event normally.
 147       }
 148     }
 149     if (!keepGoing) {
 150       // The onclick method ran successfully and returned false, meaning the
 151       // event should not bubble up, so we will return here.
 152       return;
 153     }
 154   }
 155
 156   // Send a mousedown (or simply a double click if requested).
 157   var evt = document.createEvent('MouseEvents');
 158   var evtType = opt_double ? 'dblclick' : 'mousedown';
 159   evt.initMouseEvent(evtType, true, true, document.defaultView,
 160                      1, 0, 0, 0, 0, false, false, shiftKey, false, 0, null);
 161   // Mark any events we generate so we don't try to process our own events.
 162   evt.fromCvox = true;
 163   try {
 164     targetNode.dispatchEvent(evt);
 165   } catch (e) {}
 166   //Send a mouse up
 167   evt = document.createEvent('MouseEvents');
 168   evt.initMouseEvent('mouseup', true, true, document.defaultView,
 169                      1, 0, 0, 0, 0, false, false, shiftKey, false, 0, null);
 170   // Mark any events we generate so we don't try to process our own events.
 171   evt.fromCvox = true;
 172   try {
 173     targetNode.dispatchEvent(evt);
 174   } catch (e) {}
 175   //Send a click
 176   evt = document.createEvent('MouseEvents');
 177   evt.initMouseEvent('click', true, true, document.defaultView,
 178                      1, 0, 0, 0, 0, false, false, shiftKey, false, 0, null);
 179   // Mark any events we generate so we don't try to process our own events.
 180   evt.fromCvox = true;
 181   try {
 182     targetNode.dispatchEvent(evt);
 183   } catch (e) {}
 184 };