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      1 /**
      2  * Copyright (c) 2010 The Chromium Authors. All rights reserved.  Use of this
      3  * source code is governed by a BSD-style license that can be found in the
      4  * LICENSE file.
      5  */
      6 
      7 var TEXT_NODE = 3; // Text nodes have nodeType of 3.
      8 
      9 /**
     10  * Toggles the display of nodes given the status of their associated controls.
     11  *
     12  * For each node passed to this function, check to see if a toggle has been
     13  * inserted into the node's parent.  If yes, change the state of the toggle and
     14  * hide/reveal the node as needed.
     15  *
     16  * @param {NodeList|Node|Array.<Node>} Nodes to operate on.
     17  */
     18 function toggleList(list) {
     19   if (typeof list.length != 'number') {
     20     list = Array(list);
     21   }
     22 
     23   for (var i = 0; i < list.length; i++) {
     24     var toggle = list[i].parentNode &&
     25                  list[i].parentNode.firstChild;
     26     if (toggle && toggle.className.substring(0, 6) == 'toggle') {
     27       var visible = toggle.className == 'toggle';
     28       list[i].style.display = visible ? 'block' : 'none';
     29       toggle.className = visible ? 'toggle selected' : 'toggle';
     30     }
     31   }
     32 };
     33 
     34 /**
     35  * Reveals the hidden ancestor of the passed node, adjusts toggles as needed.
     36  *
     37  * @param {Node} node The node whose ancestor is a hidden toggleable element.
     38  */
     39 function revealAncestor(node) {
     40   while (node.parentNode) {
     41     if (node.style.display == 'none') {
     42       toggleList(node);
     43       break;
     44     }
     45     node = node.parentNode;
     46   }
     47 };
     48 
     49 /**
     50  * Adds toggle controls to the sidebar list.
     51  *
     52  * Controls are inserted as the first children of list items in the sidebar
     53  * which contain only text (not a link).  Handlers are set up so that when a
     54  * toggle control is clicked, any <ul> elements who are siblings of the control
     55  * are hidden/revealed as appropriate given the control's state.
     56  *
     57  * If a list item possesses the class "leftNavSelected" its ancestor <ul> is
     58  * revealed by default (it represents the current page).
     59  */
     60 function initToggles() {
     61   var toc = document.getElementById('gc-toc');
     62   var items = toc.getElementsByTagName('li');
     63   var selectedNode = null;
     64   for (var i = 0; i < items.length; i++) {
     65     var item = items[i];
     66     if (item.className == 'leftNavSelected') {
     67       selectedNode = item;
     68     } else if (item.firstChild &&
     69                item.firstChild.nodeType == TEXT_NODE) {
     70       // Only assign toggles to text nodes in the sidebar.
     71       var a = document.createElement('a');
     72       a.className = 'toggle selected';
     73       a.appendChild(document.createTextNode(' '));
     74       a.onclick = function() {
     75         toggleList(this.parentNode.getElementsByTagName('ul'));
     76       };
     77       item.insertBefore(a, item.firstChild);
     78       toggleList(item.getElementsByTagName('ul'));
     79     }
     80   }
     81   if (selectedNode) {
     82     revealAncestor(selectedNode);
     83   }
     84 };
     85