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

chrome/browser/resources/access_chromevox/common/selection_walker.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 A JavaScript class for walking the page using WebKit
+ * selection.
+ */
+
+
+goog.provide('cvox.SelectionWalker');
+
+goog.require('cvox.SelectionUtil');
+goog.require('cvox.TraverseContent');
+
+/**
+ * @constructor
+ */
+cvox.SelectionWalker = function() {
+  this.traverseContent = new cvox.TraverseContent();
+  this.currentGranularity = 0;
+};
+
+/**
+ * @type {Object}
+ */
+cvox.SelectionWalker.GRANULARITY_LEVELS = new Array('paragraph',
+    'sentence', 'word', 'character');
+
+/**
+ * Decreases the granularity.
+ * @return {boolean} Returns true if the granularity was changed successfully.
+ */
+cvox.SelectionWalker.prototype.lessGranular = function() {
+  this.currentGranularity = this.currentGranularity - 1;
+  if (this.currentGranularity < 0) {
+    this.currentGranularity = 0;
+    return false;
+  }
+  return true;
+};
+
+/**
+ * Increases the granularity.
+ * @return {boolean} Returns true if the granularity was changed successfully.
+ */
+cvox.SelectionWalker.prototype.moreGranular = function() {
+  this.currentGranularity = this.currentGranularity + 1;
+  var max = cvox.SelectionWalker.GRANULARITY_LEVELS.length - 1;
+  if (this.currentGranularity > max) {
+    this.currentGranularity = max;
+    return false;
+  }
+  return true;
+};
+
+/**
+ * Moves selection to the next item.
+ * @return {boolean} Returns true if the selection was moved successfully.
+ */
+cvox.SelectionWalker.prototype.next = function() {
+  var status = this.traverseContent.nextElement(
+      cvox.SelectionWalker.GRANULARITY_LEVELS[this.currentGranularity]);
+  return !!status;
+};
+
+/**
+ * Moves selection to the previous item.
+ * @return {boolean} Returns true if the selection was moved successfully.
+ */
+cvox.SelectionWalker.prototype.previous = function() {
+  var status = this.traverseContent.prevElement(
+      cvox.SelectionWalker.GRANULARITY_LEVELS[this.currentGranularity]);
+  return !!status;
+};
+
+/**
+ * Returns the current granularity setting.
+ * @return {string} The granularity setting.
+ */
+cvox.SelectionWalker.prototype.getGranularity = function() {
+  return cvox.SelectionWalker.GRANULARITY_LEVELS[this.currentGranularity];
+};
+
+/**
+ * Sets the node that the SelectionWalker should be moving through.
+ * @param {Node} currentNode The node to set the SelectionWalker to.
+ */
+cvox.SelectionWalker.prototype.setCurrentNode = function(currentNode) {
+  this.traverseContent = new cvox.TraverseContent(currentNode);
+  this.traverseContent.reset();
+};
+
+/**
+ * Returns the current content of the selection.
+ * @return {string} The content of the selection.
+ */
+cvox.SelectionWalker.prototype.getCurrentContent = function() {
+  // TODO (dmazzoni, clchen): Implement getting content from virtual navigation
+  // here.
+  return cvox.SelectionUtil.getText();
+};
+