chrome/browser/resources/chromeos/chromevox/common/cursor.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  * @fileoverview Simple class to represent a cursor location in the document.
   7  */
   8
   9 goog.provide('cvox.Cursor');
  10
  11 /**
  12  * A class to represent a cursor location in the document,
  13  * like the start position or end position of a selection range.
  14  *
  15  * Later this may be extended to support "virtual text" for an object,
  16  * like the ALT text for an image.
  17  *
  18  * Note: we cache the text of a particular node at the time we
  19  * traverse into it. Later we should add support for dynamically
  20  * reloading it.
  21  * NOTE: Undefined behavior if node is null
  22  * @param {Node} node The DOM node.
  23  * @param {number} index The index of the character within the node.
  24  * @param {string} text The cached text contents of the node.
  25  * @constructor
  26  */
  27 cvox.Cursor = function(node, index, text) {
  28   this.node = node;
  29   this.index = index;
  30   this.text = text;
  31 };
  32
  33 /**
  34  * @return {!cvox.Cursor} A new cursor pointing to the same location.
  35  */
  36 cvox.Cursor.prototype.clone = function() {
  37   return new cvox.Cursor(this.node, this.index, this.text);
  38 };
  39
  40 /**
  41  * Modify this cursor to point to the location that another cursor points to.
  42  * @param {!cvox.Cursor} otherCursor The cursor to copy from.
  43  */
  44 cvox.Cursor.prototype.copyFrom = function(otherCursor) {
  45   this.node = otherCursor.node;
  46   this.index = otherCursor.index;
  47   this.text = otherCursor.text;
  48 };
  49
  50 /**
  51  * Check for equality.
  52  * @param {!cvox.Cursor} rhs The cursor to compare against.
  53  * @return {boolean} True if equal.
  54  */
  55 cvox.Cursor.prototype.equals = function(rhs) {
  56   return this.node == rhs.node &&
  57       this.index == rhs.index &&
  58       this.text == rhs.text;
  59 };