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

chrome/browser/resources/access_chromevox/chromevox/injected/navigation_manager.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 Manages navigation within a page.
+ * This unifies navigation by the DOM walker and by WebKit selection.
+ */
+
+goog.provide('cvox.ChromeVoxNavigationManager');
+
+goog.require('cvox.ChromeVoxChoiceWidget');
+goog.require('cvox.DomUtil');
+goog.require('cvox.LinearDomWalker');
+goog.require('cvox.SelectionUtil');
+goog.require('cvox.SelectionWalker');
+
+/**
+ * @constructor
+ */
+cvox.ChromeVoxNavigationManager = function() {
+  this.currentNode = null;
+  this.nodeInformationArray = new Array();
+  this.currentNavStrategy = 2;
+  this.lastUsedNavStrategy = 2;
+  this.linearDomWalker = new cvox.LinearDomWalker();
+  this.selectionWalker = new cvox.SelectionWalker();
+  this.customWalker = null;
+  this.selectionUniqueAncestors = [];
+  this.choiceWidget = new cvox.ChromeVoxChoiceWidget();
+};
+
+/**
+ * @type {Object.<string, number>}
+ */
+cvox.ChromeVoxNavigationManager.STRATEGIES =
+    {'SELECTION' : 0, 'LINEARDOM' : 1, 'SMART' : 2, 'CUSTOM' : 3};
+
+/**
+ * @type {Array.<string>}
+ */
+cvox.ChromeVoxNavigationManager.STRATEGY_NAMES =
+    ['SELECTION', 'OBJECT', 'GROUP', 'CUSTOM'];
+
+/**
+ * Moves forward using the current navigation strategy.
+ */
+cvox.ChromeVoxNavigationManager.prototype.next = function() {
+  switch (this.currentNavStrategy) {
+    default:
+    case cvox.ChromeVoxNavigationManager.STRATEGIES.CUSTOM:
+      this.customWalker.next();
+      break;
+    case cvox.ChromeVoxNavigationManager.STRATEGIES.SMART:
+    case cvox.ChromeVoxNavigationManager.STRATEGIES.LINEARDOM:
+      var node = this.linearDomWalker.next();
+      if (node) {
+        cvox.SelectionUtil.selectAllTextInNode(node);
+        this.currentNode = node;
+      }
+      break;
+
+    case cvox.ChromeVoxNavigationManager.STRATEGIES.SELECTION:
+      this.selectionUniqueAncestors = [];
+      var movedOk = this.selectionWalker.next();
+      if (!movedOk) {
+        var selectionNode = this.linearDomWalker.next();
+        this.selectionUniqueAncestors =
+            this.linearDomWalker.getUniqueAncestors();
+        if (selectionNode) {
+          this.currentNode = selectionNode;
+          this.selectionWalker.setCurrentNode(this.currentNode);
+          this.selectionWalker.next();
+        }
+      }
+      break;
+  }
+};
+
+/**
+ * Moves backward using the current navigation strategy.
+ */
+cvox.ChromeVoxNavigationManager.prototype.previous = function() {
+  switch (this.currentNavStrategy) {
+    default:
+    case cvox.ChromeVoxNavigationManager.STRATEGIES.CUSTOM:
+      this.customWalker.previous();
+      break;
+    case cvox.ChromeVoxNavigationManager.STRATEGIES.SMART:
+    case cvox.ChromeVoxNavigationManager.STRATEGIES.LINEARDOM:
+      var node = this.linearDomWalker.previous();
+      if (node) {
+        cvox.SelectionUtil.selectAllTextInNode(node);
+        this.currentNode = node;
+      }
+      break;
+
+    case cvox.ChromeVoxNavigationManager.STRATEGIES.SELECTION:
+      this.selectionUniqueAncestors = [];
+      var movedOk = this.selectionWalker.previous();
+      if (!movedOk) {
+        var selectionNode = this.linearDomWalker.previous();
+        this.selectionUniqueAncestors =
+            this.linearDomWalker.getUniqueAncestors();
+        if (selectionNode) {
+          this.currentNode = selectionNode;
+          this.selectionWalker.setCurrentNode(this.currentNode);
+          cvox.SelectionUtil.selectAllTextInNode(this.currentNode);
+          window.getSelection().collapseToEnd();
+          this.selectionWalker.previous();
+        }
+      }
+      break;
+  }
+};
+
+/**
+ * Moves up a level of granularity.
+ */
+cvox.ChromeVoxNavigationManager.prototype.up = function() {
+  switch (this.currentNavStrategy) {
+    default:
+    case cvox.ChromeVoxNavigationManager.STRATEGIES.CUSTOM:
+      break;
+    case cvox.ChromeVoxNavigationManager.STRATEGIES.SMART:
+      if (!!this.customWalker) {
+        this.lastUsedNavStrategy = this.currentNavStrategy;
+        this.currentNavStrategy = 3;
+        this.customWalker.setCurrentNode(this.currentNode);
+        this.customWalker.goToCurrentItem();
+      }
+      break;
+
+    case cvox.ChromeVoxNavigationManager.STRATEGIES.LINEARDOM:
+      this.lastUsedNavStrategy = this.currentNavStrategy;
+      this.currentNavStrategy = 2;
+      this.linearDomWalker.setSmartNavEnabled(true);
+      var node = this.currentNode;
+      while (this.linearDomWalker.isLeafNode(node)) {
+        this.currentNode = node;
+        node = node.parentNode;
+      }
+      this.linearDomWalker.setCurrentNode(this.currentNode);
+      if (this.currentNode !== null) {
+        this.previous();
+      }
+      this.next();
+      break;
+
+    case cvox.ChromeVoxNavigationManager.STRATEGIES.SELECTION:
+      var changed = this.selectionWalker.lessGranular();
+      if (!changed) {
+        this.lastUsedNavStrategy = this.currentNavStrategy;
+        this.currentNavStrategy = 1;
+        cvox.SelectionUtil.selectAllTextInNode(this.currentNode);
+      } else {
+        this.selectionWalker.previous();
+        this.selectionWalker.next();
+      }
+      break;
+  }
+};
+
+
+/**
+ * Moves down a level of granularity.
+ */
+cvox.ChromeVoxNavigationManager.prototype.down = function() {
+  switch (this.currentNavStrategy) {
+    default:
+    case cvox.ChromeVoxNavigationManager.STRATEGIES.CUSTOM:
+      this.lastUsedNavStrategy = this.currentNavStrategy;
+      this.currentNavStrategy = 2;
+      this.linearDomWalker.setSmartNavEnabled(true);
+      if (this.customWalker.getCurrentNode() != null) {
+        this.currentNode = this.customWalker.getCurrentNode();
+        this.linearDomWalker.setCurrentNode(this.currentNode);
+      }
+      break;
+    case cvox.ChromeVoxNavigationManager.STRATEGIES.SMART:
+      this.lastUsedNavStrategy = this.currentNavStrategy;
+      this.currentNavStrategy = 1;
+      this.linearDomWalker.setSmartNavEnabled(false);
+      if (this.currentNode !== null) {
+        this.previous();
+      }
+      this.next();
+      break;
+
+    case cvox.ChromeVoxNavigationManager.STRATEGIES.LINEARDOM:
+      this.lastUsedNavStrategy = this.currentNavStrategy;
+      this.currentNavStrategy = 0;
+      this.selectionWalker.setCurrentNode(this.currentNode);
+      this.selectionWalker.next();
+      break;
+
+    case cvox.ChromeVoxNavigationManager.STRATEGIES.SELECTION:
+      var changed = this.selectionWalker.moreGranular();
+      if (changed) {
+        this.selectionWalker.previous();
+        this.selectionWalker.next();
+      }
+      break;
+  }
+};
+
+/**
+ * Moves to the next occurrence of a node that matches the given predicate,
+ * if one exists, using the linearDomWalker.
+ * @param {function(Array.<Node>)} predicate A function taking an array
+ *     of unique ancestor nodes as a parameter and returning true if it's
+ *     what to search for.
+ * @return {boolean} True if a match was found.
+ */
+cvox.ChromeVoxNavigationManager.prototype.findNext = function(predicate) {
+  this.syncPosition();
+  var node = undefined;
+  while (true) {
+    node = this.linearDomWalker.next();
+    if (!node) {
+      break;
+    }
+
+    if (predicate(this.linearDomWalker.getUniqueAncestors())) {
+      break;
+    }
+  }
+
+  if (node) {
+    cvox.SelectionUtil.selectAllTextInNode(node);
+    this.currentNode = node;
+    return true;
+  }
+
+  return false;
+};
+
+/**
+ * Moves to the previous occurrence of a node that matches the given predicate,
+ * if one exists, using the linearDomWalker.
+ * @param {function(Array.<Node>)} predicate A function taking an array
+ *     of unique ancestor nodes as a parameter and returning true if it's
+ *     what to search for.
+ * @return {boolean} True if a match was found.
+ */
+cvox.ChromeVoxNavigationManager.prototype.findPrevious = function(predicate) {
+  this.syncPosition();
+  var node = undefined;
+  while (true) {
+    node = this.linearDomWalker.previous();
+    if (!node) {
+      break;
+    }
+
+    if (predicate(this.linearDomWalker.getUniqueAncestors())) {
+      break;
+    }
+  }
+
+  if (node) {
+    cvox.SelectionUtil.selectAllTextInNode(node);
+    this.currentNode = node;
+    return true;
+  }
+
+  return false;
+};
+
+/**
+ * Returns the current navigation strategy.
+ *
+ * @return {string} The strategy that is being used.
+ */
+cvox.ChromeVoxNavigationManager.prototype.getStrategy = function() {
+  return cvox.ChromeVoxNavigationManager.STRATEGY_NAMES[
+    this.currentNavStrategy];
+};
+
+/**
+ * Returns the current selection granularity.
+ *
+ * @return {string} The selection granularity that is being used.
+ */
+cvox.ChromeVoxNavigationManager.prototype.getGranularity = function() {
+  return this.selectionWalker.getGranularity();
+};
+
+/**
+ * Synchronizes the current position between the different navigation
+ * strategies.
+ */
+cvox.ChromeVoxNavigationManager.prototype.syncPosition = function() {
+  if (!this.currentNode) {
+    this.currentNode = document.body;
+  }
+  if (this.currentNavStrategy != this.lastUsedNavStrategy) {
+    if ((this.lastUsedNavStrategy ==
+             cvox.ChromeVoxNavigationManager.STRATEGIES.LINEARDOM) ||
+        (this.lastUsedNavStrategy ==
+             cvox.ChromeVoxNavigationManager.STRATEGIES.SMART)) {
+      this.syncToNode(this.currentNode);
+    } else {
+      this.syncToSelection();
+    }
+  }
+  this.lastUsedNavStrategy = this.currentNavStrategy;
+};
+
+/**
+ * Synchronizes the navigation strategies to the current selection.
+ */
+cvox.ChromeVoxNavigationManager.prototype.syncToSelection = function() {
+  if (window.getSelection() && window.getSelection().anchorNode) {
+    this.currentNode = window.getSelection().anchorNode;
+    this.linearDomWalker.setCurrentNode(this.currentNode);
+  }
+};
+
+/**
+ * Synchronizes the navigation strategies to the targetNode.
+ *
+ * @param {Node} targetNode The node that the navigation strategies should be
+ * synced to.
+ */
+cvox.ChromeVoxNavigationManager.prototype.syncToNode = function(targetNode) {
+  if (cvox.DomUtil.isDescendantOfNode(this.currentNode, targetNode)) {
+    // User is already synced at a more specific level than the target;
+    // therefore ignore the sync request.
+    return;
+  }
+  this.currentNode = targetNode;
+  this.linearDomWalker.setCurrentNode(targetNode);
+  var range = document.createRange();
+  range.selectNode(this.currentNode);
+  window.getSelection().removeAllRanges();
+  window.getSelection().addRange(range);
+  window.getSelection().collapseToStart();
+};
+
+/**
+ * Returns only the text content for the current position.
+ *
+ * @return {string} The current text content.
+ */
+cvox.ChromeVoxNavigationManager.prototype.getCurrentContent = function() {
+  switch (this.currentNavStrategy) {
+    default:
+    case cvox.ChromeVoxNavigationManager.STRATEGIES.CUSTOM:
+      return this.customWalker.getCurrentContent();
+      break;
+    case cvox.ChromeVoxNavigationManager.STRATEGIES.SMART:
+    case cvox.ChromeVoxNavigationManager.STRATEGIES.LINEARDOM:
+      return cvox.DomUtil.getText(this.currentNode);
+      break;
+
+    case cvox.ChromeVoxNavigationManager.STRATEGIES.SELECTION:
+      return this.selectionWalker.getCurrentContent();
+      break;
+  }
+};
+
+/**
+ * Returns a complete description of the current position, including
+ * the text content and annotations such as "link", "button", etc.
+ *
+ * @return {string} The summary of the current position.
+ */
+cvox.ChromeVoxNavigationManager.prototype.getCurrentDescription = function() {
+  switch (this.currentNavStrategy) {
+    default:
+    case cvox.ChromeVoxNavigationManager.STRATEGIES.CUSTOM:
+      return this.customWalker.getCurrentDescription();
+      break;
+    case cvox.ChromeVoxNavigationManager.STRATEGIES.SMART:
+      // Use a linear DOM walker in non-smart mode to traverse all of the
+      // nodes inside the current smart node and append all of their
+      // descriptions.
+      var description = '';
+      var walker = new cvox.LinearDomWalker();
+      walker.currentNode = this.linearDomWalker.currentNode;
+      walker.useSmartNav = false;
+      walker.previous();
+      walker.next();
+      while (cvox.DomUtil.isDescendantOfNode(
+                 walker.currentNode, this.linearDomWalker.currentNode)) {
+        description = description + ' ' +
+            cvox.DomUtil.getText(walker.currentNode) + ' ' +
+            cvox.DomUtil.getInformationFromAncestors(
+                walker.getUniqueAncestors());
+        walker.next();
+      }
+      return description;
+
+    case cvox.ChromeVoxNavigationManager.STRATEGIES.LINEARDOM:
+      return this.getCurrentContent() + ' ' +
+      cvox.DomUtil.getInformationFromAncestors(this.getChangedAncestors());
+
+    case cvox.ChromeVoxNavigationManager.STRATEGIES.SELECTION:
+      return this.getCurrentContent() + ' ' +
+      cvox.DomUtil.getInformationFromAncestors(
+          this.selectionUniqueAncestors);
+  }
+};
+
+/**
+ * Returns an array of ancestor nodes that have been changed between the
+ * previous position and the current current position.
+ *
+ * @return {Array.<Node>} The current content.
+ */
+cvox.ChromeVoxNavigationManager.prototype.getChangedAncestors = function() {
+  return this.linearDomWalker.getUniqueAncestors();
+};
+
+/**
+ * Sets the browser's focus to the current node.
+ */
+cvox.ChromeVoxNavigationManager.prototype.setFocus = function() {
+  cvox.DomUtil.setFocus(this.linearDomWalker.getCurrentNode());
+};
+
+/**
+ * Acts on the current item and displays a disambiguation dialog
+ * if more than one action is possible.
+ *
+ * @return {boolean} True if an action was taken.
+ */
+cvox.ChromeVoxNavigationManager.prototype.actOnCurrentItem = function() {
+  if (this.currentNavStrategy ==
+      cvox.ChromeVoxNavigationManager.STRATEGIES.CUSTOM) {
+    return this.customWalker.actOnCurrentItem();
+  } else if (this.currentNavStrategy ==
+      cvox.ChromeVoxNavigationManager.STRATEGIES.SMART) {
+    if (this.currentNode && this.currentNode.tagName &&
+        (this.currentNode.tagName == 'A')) {
+      cvox.DomUtil.clickElem(this.currentNode, false);
+      return true;
+    } else {
+      var aNodes = this.currentNode.getElementsByTagName('A');
+      if (aNodes.length == 1) {
+        cvox.DomUtil.clickElem(aNodes[0], false);
+        return true;
+      } else if (aNodes.length > 1) {
+        var descriptions = new Array();
+        var functions = new Array();
+        for (var i = 0, link; link = aNodes[i]; i++) {
+          if (cvox.DomUtil.hasContent(link)) {
+            descriptions.push(cvox.DomUtil.getText(link));
+            functions.push(cvox.ChromeVoxNavigationManager
+                .createSimpleClickFunction(link));
+          }
+        }
+        this.choiceWidget.show(descriptions, functions,
+            descriptions.toString());
+        return true;
+      }
+    }
+  }
+  return false;
+};
+
+/**
+ * Checks if the navigation manager is able to act on the current item.
+ *
+ * @return {boolean} True if some action is possible.
+ */
+cvox.ChromeVoxNavigationManager.prototype.canActOnCurrentItem = function() {
+  if (this.currentNavStrategy ==
+      cvox.ChromeVoxNavigationManager.STRATEGIES.CUSTOM) {
+    return this.customWalker.canActOnCurrentItem();
+  }
+  if (this.currentNavStrategy ==
+      cvox.ChromeVoxNavigationManager.STRATEGIES.SMART) {
+    if (this.currentNode && this.currentNode.tagName &&
+        (this.currentNode.tagName == 'A')) {
+      return true;
+    } else {
+      var aNodes = this.currentNode.getElementsByTagName('A');
+      if (aNodes.length > 0) {
+        return true;
+      }
+    }
+  }
+  // Anything that is DOM level or lower will always be handled by the browser.
+  return false;
+};
+
+/**
+ * Creates a simple function that will click on the given targetNode when
+ * invoked.
+ * Note that we are using this function because functions created inside a loop
+ * have to be created by another function and not within the loop directly.
+ *
+ * See: http://joust.kano.net/weblog/archive/2005/08/08/
+ * a-huge-gotcha-with-javascript-closures/
+ * @param {Node} targetNode The target node to click on.
+ * @return {function()} A function that will click on the given targetNode.
+ */
+cvox.ChromeVoxNavigationManager.createSimpleClickFunction = function(
+    targetNode) {
+  var target = targetNode.cloneNode(true);
+  return function() { cvox.DomUtil.clickElem(target, false); };
+};
+
+/**
+ * Sets the custom walker to use for the current site.
+ *
+ * @param {Object} customWalkerObj The custom walker to use.
+ */
+cvox.ChromeVoxNavigationManager.prototype.setCustomWalker =
+    function(customWalkerObj) {
+  this.customWalker = customWalkerObj;
+  this.currentNavStrategy = 3;
+  this.lastUsedNavStrategy = 3;
+};
+