chrome/browser/resources/chromeos/chromevox/common/find_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  * @fileoverview Utilities for finding DOM nodes and CursorSelection's.
   7  */
   8
   9
  10 goog.provide('cvox.FindUtil');
  11
  12 goog.require('cvox.BareObjectWalker');
  13 goog.require('cvox.CursorSelection');
  14
  15
  16 /**
  17  * @type {!cvox.BareObjectWalker}
  18  * @private
  19  */
  20 cvox.FindUtil.objectWalker_ = new cvox.BareObjectWalker();
  21
  22
  23 /**
  24  * Finds the next selection that matches the predicate function starting from
  25  * sel. Undefined if the nodes in sel are not attached to the document.
  26  * @param {!cvox.CursorSelection} sel The selection from which to start.
  27  * @param {function(Array<Node>):Node} predicate A function taking a
  28  * unique ancestor tree and outputting Node if the ancestor tree matches
  29  * the desired node to find.
  30  * @param {boolean=} opt_initialNode Whether to start the search from node
  31  * (true), or the next node (false); defaults to false.
  32  * @return {cvox.CursorSelection} The selection that was found.
  33  * null if end of document reached.
  34  */
  35 cvox.FindUtil.findNext = function(sel, predicate, opt_initialNode) {
  36   var r = sel.isReversed();
  37   var cur = new cvox.CursorSelection(sel.absStart(), sel.absStart())
  38       .setReversed(r);
  39
  40   // We may have been sync'ed into a subtree of the current predicate match.
  41   // Find our ancestor that matches the predicate.
  42   var ancestor;
  43   if (ancestor = predicate(cvox.DomUtil.getAncestors(cur.start.node))) {
  44     cur = cvox.CursorSelection.fromNode(ancestor).setReversed(r);
  45     if (opt_initialNode) {
  46       return cur;
  47     }
  48   }
  49
  50   while (cur) {
  51     // Use ObjectWalker's traversal which guarantees us a stable iteration of
  52     // the DOM including returning null at page bounds.
  53     cur = cvox.FindUtil.objectWalker_.next(cur);
  54     var retNode = null;
  55     if (!cur ||
  56         (retNode = predicate(cvox.DomUtil.getAncestors(cur.start.node)))) {
  57       return retNode ? cvox.CursorSelection.fromNode(retNode) : null;
  58     }
  59
  60     // Iframes require inter-frame messaging.
  61     if (cur.start.node.tagName == 'IFRAME') {
  62       return cur;
  63     }
  64   }
  65   return null;
  66 };