internal/godoc/static/godocs.js - website - Git at Google

 // Copyright 2012 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.

 /* A little code to ease navigation of these documents.
  *
  * On window load we:
  *  + Generate a table of contents (generateTOC)
  *  + Bind foldable sections (bindToggles)
  *  + Bind links to foldable sections (bindToggleLinks)
  */

 (function() {
   'use strict';

   // Mobile-friendly topbar menu
   $(function() {
     var menu = $('#menu');
     var menuButton = $('#menu-button');
     var menuButtonArrow = $('#menu-button-arrow');
     menuButton.click(function(event) {
       menu.toggleClass('menu-visible');
       menuButtonArrow.toggleClass('vertical-flip');
       event.preventDefault();
       return false;
     });
   });

   /* Generates a table of contents: looks for h2 and h3 elements and generates
    * links. "Decorates" the element with id=="nav" with this table of contents.
    */
   function generateTOC() {
     if ($('#manual-nav').length > 0) {
       return;
     }

     // For search, we send the toc precomputed from server-side.
     // TODO: Ideally, this should always be precomputed for all pages, but then
     // we need to do HTML parsing on the server-side.
     if (location.pathname === '/search') {
       return;
     }

     var nav = $('#nav');
     if (nav.length === 0) {
       return;
     }

     var toc_items = [];
     $(nav)
       .nextAll('h2, h3')
       .each(function() {
         var node = this;
         if (node.id == '') node.id = 'tmp_' + toc_items.length;
         var link = $('<a/>')
           .attr('href', '#' + node.id)
           .text($(node).text());
         var item;
         if ($(node).is('h2')) {
           item = $('<dt/>');
         } else {
           // h3
           item = $('<dd class="indent"/>');
         }
         item.append(link);
         toc_items.push(item);
       });
     if (toc_items.length <= 1) {
       return;
     }
     var dl1 = $('<dl/>');
     var dl2 = $('<dl/>');

     var split_index = toc_items.length / 2 + 1;
     if (split_index < 8) {
       split_index = toc_items.length;
     }
     for (var i = 0; i < split_index; i++) {
       dl1.append(toc_items[i]);
     }
     for (; /* keep using i */ i < toc_items.length; i++) {
       dl2.append(toc_items[i]);
     }

     var tocTable = $('<table class="unruled"/>').appendTo(nav);
     var tocBody = $('<tbody/>').appendTo(tocTable);
     var tocRow = $('<tr/>').appendTo(tocBody);

     // 1st column
     $('<td class="first"/>')
       .appendTo(tocRow)
       .append(dl1);
     // 2nd column
     $('<td/>')
       .appendTo(tocRow)
       .append(dl2);
   }

   function bindToggle(el) {
     $('.toggleButton', el).click(function() {
       if ($(this).closest('.toggle, .toggleVisible')[0] != el) {
         // Only trigger the closest toggle header.
         return;
       }

       if ($(el).is('.toggle')) {
         $(el)
           .addClass('toggleVisible')
           .removeClass('toggle');
       } else {
         $(el)
           .addClass('toggle')
           .removeClass('toggleVisible');
       }
     });
   }

   function bindToggles(selector) {
     $(selector).each(function(i, el) {
       bindToggle(el);
     });
   }

   function bindToggleLink(el, prefix) {
     $(el).click(function() {
       var href = $(el).attr('href');
       var i = href.indexOf('#' + prefix);
       if (i < 0) {
         return;
       }
       var id = '#' + prefix + href.slice(i + 1 + prefix.length);
       if ($(id).is('.toggle')) {
         $(id)
           .find('.toggleButton')
           .first()
           .click();
       }
     });
   }
   function bindToggleLinks(selector, prefix) {
     $(selector).each(function(i, el) {
       bindToggleLink(el, prefix);
     });
   }

   function setupDropdownPlayground() {
     if (!$('#page').is('.wide')) {
       return; // don't show on front page
     }
     var button = $('#playgroundButton');
     var div = $('#playground');
     var setup = false;
     button.toggle(
       function() {
         button.addClass('active');
         div.show();
         if (setup) {
           return;
         }
         setup = true;
         playground({
           codeEl: $('.code', div),
           outputEl: $('.output', div),
           runEl: $('.run', div),
           fmtEl: $('.fmt', div),
           shareEl: $('.share', div),
           shareRedirect: '//play.golang.org/p/',
         });
       },
       function() {
         button.removeClass('active');
         div.hide();
       }
     );
     $('#menu').css('min-width', '+=60');

     // Hide inline playground if we click somewhere on the page.
     // This is needed in mobile devices, where the "Play" button
     // is not clickable once the playground opens up.
     $('#page').click(function() {
       if (button.hasClass('active')) {
         button.click();
       }
     });
   }

   function setupInlinePlayground() {
     'use strict';
     // Set up playground when each element is toggled.
     $('div.play').each(function(i, el) {
       // Set up playground for this example.
       var setup = function() {
         var code = $('.code', el);
         playground({
           codeEl: code,
           outputEl: $('.output', el),
           runEl: $('.run', el),
           fmtEl: $('.fmt', el),
           shareEl: $('.share', el),
           shareRedirect: '//play.golang.org/p/',
         });

         // Make the code textarea resize to fit content.
         var resize = function() {
           code.height(0);
           var h = code[0].scrollHeight;
           code.height(h + 20); // minimize bouncing.
           code.closest('.input').height(h);
         };
         code.on('keydown', resize);
         code.on('keyup', resize);
         code.keyup(); // resize now.
       };

       // If example already visible, set up playground now.
       if ($(el).is(':visible')) {
         setup();
         return;
       }

       // Otherwise, set up playground when example is expanded.
       var built = false;
       $(el)
         .closest('.toggle')
         .click(function() {
           // Only set up once.
           if (!built) {
             setup();
             built = true;
           }
         });
     });
   }

   // fixFocus tries to put focus to div#page so that keyboard navigation works.
   function fixFocus() {
     var page = $('div#page');
     var topbar = $('div#topbar');
     page.css('outline', 0); // disable outline when focused
     page.attr('tabindex', -1); // and set tabindex so that it is focusable
     $(window)
       .resize(function(evt) {
         // only focus page when the topbar is at fixed position (that is, it's in
         // front of page, and keyboard event will go to the former by default.)
         // by focusing page, keyboard event will go to page so that up/down arrow,
         // space, etc. will work as expected.
         if (topbar.css('position') == 'fixed') page.focus();
       })
       .resize();
   }

   function toggleHash() {
     var id = window.location.hash.substring(1);
     // Open all of the toggles for a particular hash.
     var els = $(
       document.getElementById(id),
       $('a[name]').filter(function() {
         return $(this).attr('name') == id;
       })
     );

     while (els.length) {
       for (var i = 0; i < els.length; i++) {
         var el = $(els[i]);
         if (el.is('.toggle')) {
           el.find('.toggleButton')
             .first()
             .click();
         }
       }
       els = el.parent();
     }
   }

   function personalizeInstallInstructions() {
     var prefix = '?download=';
     var s = window.location.search;
     if (s.indexOf(prefix) != 0) {
       // No 'download' query string; detect "test" instructions from User Agent.
       if (navigator.platform.indexOf('Win') != -1) {
         $('.testUnix').hide();
         $('.testWindows').show();
       } else {
         $('.testUnix').show();
         $('.testWindows').hide();
       }
       return;
     }

     var filename = s.substr(prefix.length);
     var filenameRE = /^go1\.\d+(\.\d+)?([a-z0-9]+)?\.([a-z0-9]+)(-[a-z0-9]+)?(-osx10\.[68])?\.([a-z.]+)$/;
     var m = filenameRE.exec(filename);
     if (!m) {
       // Can't interpret file name; bail.
       return;
     }
     $('.downloadFilename').text(filename);
     $('.hideFromDownload').hide();

     var os = m[3];
     var ext = m[6];
     if (ext != 'tar.gz') {
       $('#tarballInstructions').hide();
     }
     if (os != 'darwin' || ext != 'pkg') {
       $('#darwinPackageInstructions').hide();
     }
     if (os != 'windows') {
       $('#windowsInstructions').hide();
       $('.testUnix').show();
       $('.testWindows').hide();
     } else {
       if (ext != 'msi') {
         $('#windowsInstallerInstructions').hide();
       }
       if (ext != 'zip') {
         $('#windowsZipInstructions').hide();
       }
       $('.testUnix').hide();
       $('.testWindows').show();
     }

     var download = 'https://dl.google.com/go/' + filename;

     var message = $(
       '<p class="downloading">' +
         'Your download should begin shortly. ' +
         'If it does not, click <a>this link</a>.</p>'
     );
     message.find('a').attr('href', download);
     message.insertAfter('#nav');

     window.location = download;
   }

   function updateVersionTags() {
     var v = window.goVersion;
     if (/^go[0-9.]+$/.test(v)) {
       $('.versionTag')
         .empty()
         .text(v);
       $('.whereTag').hide();
     }
   }

   function addPermalinks() {
     function addPermalink(source, parent) {
       var id = source.attr('id');
       if (id == '' || id.indexOf('tmp_') === 0) {
         // Auto-generated permalink.
         return;
       }
       if (parent.find('> .permalink').length) {
         // Already attached.
         return;
       }
       parent
         .append(' ')
         .append($("<a class='permalink'>&#xb6;</a>").attr('href', '#' + id));
     }

     $('#page .container')
       .find('h2[id], h3[id]')
       .each(function() {
         var el = $(this);
         addPermalink(el, el);
       });

     $('#page .container')
       .find('dl[id]')
       .each(function() {
         var el = $(this);
         // Add the anchor to the "dt" element.
         addPermalink(el, el.find('> dt').first());
       });
   }

   $('.js-expandAll').click(function() {
     if ($(this).hasClass('collapsed')) {
       toggleExamples('toggle');
       $(this).text('(Collapse All)');
     } else {
       toggleExamples('toggleVisible');
       $(this).text('(Expand All)');
     }
     $(this).toggleClass('collapsed');
   });

   function toggleExamples(className) {
     // We need to explicitly iterate through divs starting with "example_"
     // to avoid toggling Overview and Index collapsibles.
     $("[id^='example_']").each(function() {
       // Check for state and click it only if required.
       if ($(this).hasClass(className)) {
         $(this)
           .find('.toggleButton')
           .first()
           .click();
       }
     });
   }

   $(document).ready(function() {
     generateTOC();
     addPermalinks();
     bindToggles('.toggle');
     bindToggles('.toggleVisible');
     bindToggleLinks('.exampleLink', 'example_');
     bindToggleLinks('.overviewLink', '');
     bindToggleLinks('.examplesLink', '');
     bindToggleLinks('.indexLink', '');
     setupDropdownPlayground();
     setupInlinePlayground();
     fixFocus();
     setupTypeInfo();
     setupCallgraphs();
     toggleHash();
     personalizeInstallInstructions();
     updateVersionTags();

     // godoc.html defines window.initFuncs in the <head> tag, and root.html and
     // codewalk.js push their on-page-ready functions to the list.
     // We execute those functions here, to avoid loading jQuery until the page
     // content is loaded.
     for (var i = 0; i < window.initFuncs.length; i++) window.initFuncs[i]();
   });

   // -- analysis ---------------------------------------------------------

   // escapeHTML returns HTML for s, with metacharacters quoted.
   // It is safe for use in both elements and attributes
   // (unlike the "set innerText, read innerHTML" trick).
   function escapeHTML(s) {
     return s
       .replace(/&/g, '&amp;')
       .replace(/\"/g, '&quot;')
       .replace(/\'/g, '&#39;')
       .replace(/</g, '&lt;')
       .replace(/>/g, '&gt;');
   }

   // makeAnchor returns HTML for an <a> element, given an anchorJSON object.
   function makeAnchor(json) {
     var html = escapeHTML(json.Text);
     if (json.Href != '') {
       html = "<a href='" + escapeHTML(json.Href) + "'>" + html + '</a>';
     }
     return html;
   }

   function showLowFrame(html) {
     var lowframe = document.getElementById('lowframe');
     lowframe.style.height = '200px';
     lowframe.innerHTML =
       "<p style='text-align: left;'>" +
       html +
       '</p>\n' +
       "<div onclick='hideLowFrame()' style='position: absolute; top: 0; right: 0; cursor: pointer;'>✘</div>";
   }

   document.hideLowFrame = function() {
     var lowframe = document.getElementById('lowframe');
     lowframe.style.height = '0px';
   };

   // onClickCallers is the onclick action for the 'func' tokens of a
   // function declaration.
   document.onClickCallers = function(index) {
     var data = document.ANALYSIS_DATA[index];
     if (data.Callers.length == 1 && data.Callers[0].Sites.length == 1) {
       document.location = data.Callers[0].Sites[0].Href; // jump to sole caller
       return;
     }

     var html =
       'Callers of <code>' + escapeHTML(data.Callee) + '</code>:<br/>\n';
     for (var i = 0; i < data.Callers.length; i++) {
       var caller = data.Callers[i];
       html += '<code>' + escapeHTML(caller.Func) + '</code>';
       var sites = caller.Sites;
       if (sites != null && sites.length > 0) {
         html += ' at line ';
         for (var j = 0; j < sites.length; j++) {
           if (j > 0) {
             html += ', ';
           }
           html += '<code>' + makeAnchor(sites[j]) + '</code>';
         }
       }
       html += '<br/>\n';
     }
     showLowFrame(html);
   };

   // onClickCallees is the onclick action for the '(' token of a function call.
   document.onClickCallees = function(index) {
     var data = document.ANALYSIS_DATA[index];
     if (data.Callees.length == 1) {
       document.location = data.Callees[0].Href; // jump to sole callee
       return;
     }

     var html = 'Callees of this ' + escapeHTML(data.Descr) + ':<br/>\n';
     for (var i = 0; i < data.Callees.length; i++) {
       html += '<code>' + makeAnchor(data.Callees[i]) + '</code><br/>\n';
     }
     showLowFrame(html);
   };

   // onClickTypeInfo is the onclick action for identifiers declaring a named type.
   document.onClickTypeInfo = function(index) {
     var data = document.ANALYSIS_DATA[index];
     var html =
       'Type <code>' +
       data.Name +
       '</code>: ' +
       '&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<small>(size=' +
       data.Size +
       ', align=' +
       data.Align +
       ')</small><br/>\n';
     html += implementsHTML(data);
     html += methodsetHTML(data);
     showLowFrame(html);
   };

   // implementsHTML returns HTML for the implements relation of the
   // specified TypeInfoJSON value.
   function implementsHTML(info) {
     var html = '';
     if (info.ImplGroups != null) {
       for (var i = 0; i < info.ImplGroups.length; i++) {
         var group = info.ImplGroups[i];
         var x = '<code>' + escapeHTML(group.Descr) + '</code> ';
         for (var j = 0; j < group.Facts.length; j++) {
           var fact = group.Facts[j];
           var y = '<code>' + makeAnchor(fact.Other) + '</code>';
           if (fact.ByKind != null) {
             html += escapeHTML(fact.ByKind) + ' type ' + y + ' implements ' + x;
           } else {
             html += x + ' implements ' + y;
           }
           html += '<br/>\n';
         }
       }
     }
     return html;
   }

   // methodsetHTML returns HTML for the methodset of the specified
   // TypeInfoJSON value.
   function methodsetHTML(info) {
     var html = '';
     if (info.Methods != null) {
       for (var i = 0; i < info.Methods.length; i++) {
         html += '<code>' + makeAnchor(info.Methods[i]) + '</code><br/>\n';
       }
     }
     return html;
   }

   // onClickComm is the onclick action for channel "make" and "<-"
   // send/receive tokens.
   document.onClickComm = function(index) {
     var ops = document.ANALYSIS_DATA[index].Ops;
     if (ops.length == 1) {
       document.location = ops[0].Op.Href; // jump to sole element
       return;
     }

     var html = 'Operations on this channel:<br/>\n';
     for (var i = 0; i < ops.length; i++) {
       html +=
         makeAnchor(ops[i].Op) +
         ' by <code>' +
         escapeHTML(ops[i].Fn) +
         '</code><br/>\n';
     }
     if (ops.length == 0) {
       html += '(none)<br/>\n';
     }
     showLowFrame(html);
   };

   $(window).load(function() {
     // Scroll window so that first selection is visible.
     // (This means we don't need to emit id='L%d' spans for each line.)
     // TODO(adonovan): ideally, scroll it so that it's under the pointer,
     // but I don't know how to get the pointer y coordinate.
     var elts = document.getElementsByClassName('selection');
     if (elts.length > 0) {
       elts[0].scrollIntoView();
     }
   });

   // setupTypeInfo populates the "Implements" and "Method set" toggle for
   // each type in the package doc.
   function setupTypeInfo() {
     for (var i in document.ANALYSIS_DATA) {
       var data = document.ANALYSIS_DATA[i];

       var el = document.getElementById('implements-' + i);
       if (el != null) {
         // el != null => data is TypeInfoJSON.
         if (data.ImplGroups != null) {
           el.innerHTML = implementsHTML(data);
           el.parentNode.parentNode.style.display = 'block';
         }
       }

       var el = document.getElementById('methodset-' + i);
       if (el != null) {
         // el != null => data is TypeInfoJSON.
         if (data.Methods != null) {
           el.innerHTML = methodsetHTML(data);
           el.parentNode.parentNode.style.display = 'block';
         }
       }
     }
   }

   function setupCallgraphs() {
     if (document.CALLGRAPH == null) {
       return;
     }
     document.getElementById('pkg-callgraph').style.display = 'block';

     var treeviews = document.getElementsByClassName('treeview');
     for (var i = 0; i < treeviews.length; i++) {
       var tree = treeviews[i];
       if (tree.id == null || tree.id.indexOf('callgraph-') != 0) {
         continue;
       }
       var id = tree.id.substring('callgraph-'.length);
       $(tree).treeview({ collapsed: true, animated: 'fast' });
       document.cgAddChildren(tree, tree, [id]);
       tree.parentNode.parentNode.style.display = 'block';
     }
   }

   document.cgAddChildren = function(tree, ul, indices) {
     if (indices != null) {
       for (var i = 0; i < indices.length; i++) {
         var li = cgAddChild(tree, ul, document.CALLGRAPH[indices[i]]);
         if (i == indices.length - 1) {
           $(li).addClass('last');
         }
       }
     }
     $(tree).treeview({ animated: 'fast', add: ul });
   };

   // cgAddChild adds an <li> element for document.CALLGRAPH node cgn to
   // the parent <ul> element ul. tree is the tree's root <ul> element.
   function cgAddChild(tree, ul, cgn) {
     var li = document.createElement('li');
     ul.appendChild(li);
     li.className = 'closed';

     var code = document.createElement('code');

     if (cgn.Callees != null) {
       $(li).addClass('expandable');

       // Event handlers and innerHTML updates don't play nicely together,
       // hence all this explicit DOM manipulation.
       var hitarea = document.createElement('div');
       hitarea.className = 'hitarea expandable-hitarea';
       li.appendChild(hitarea);

       li.appendChild(code);

       var childUL = document.createElement('ul');
       li.appendChild(childUL);
       childUL.setAttribute('style', 'display: none;');

       var onClick = function() {
         document.cgAddChildren(tree, childUL, cgn.Callees);
         hitarea.removeEventListener('click', onClick);
       };
       hitarea.addEventListener('click', onClick);
     } else {
       li.appendChild(code);
     }
     code.innerHTML += '&nbsp;' + makeAnchor(cgn.Func);
     return li;
   }
 })();
	// Copyright 2012 The Go Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style
	// license that can be found in the LICENSE file.

	/* A little code to ease navigation of these documents.
	*
	* On window load we:
	* + Generate a table of contents (generateTOC)
	* + Bind foldable sections (bindToggles)
	* + Bind links to foldable sections (bindToggleLinks)
	*/

	(function() {
	'use strict';

	// Mobile-friendly topbar menu
	$(function() {
	var menu = $('#menu');
	var menuButton = $('#menu-button');
	var menuButtonArrow = $('#menu-button-arrow');
	menuButton.click(function(event) {
	menu.toggleClass('menu-visible');
	menuButtonArrow.toggleClass('vertical-flip');
	event.preventDefault();
	return false;
	});
	});

	/* Generates a table of contents: looks for h2 and h3 elements and generates
	* links. "Decorates" the element with id=="nav" with this table of contents.
	*/
	function generateTOC() {
	if ($('#manual-nav').length > 0) {
	return;
	}

	// For search, we send the toc precomputed from server-side.
	// TODO: Ideally, this should always be precomputed for all pages, but then
	// we need to do HTML parsing on the server-side.
	if (location.pathname === '/search') {
	return;
	}

	var nav = $('#nav');
	if (nav.length === 0) {
	return;
	}

	var toc_items = [];
	$(nav)
	.nextAll('h2, h3')
	.each(function() {
	var node = this;
	if (node.id == '') node.id = 'tmp_' + toc_items.length;
	var link = $('<a/>')
	.attr('href', '#' + node.id)
	.text($(node).text());
	var item;
	if ($(node).is('h2')) {
	item = $('<dt/>');
	} else {
	// h3
	item = $('<dd class="indent"/>');
	}
	item.append(link);
	toc_items.push(item);
	});
	if (toc_items.length <= 1) {
	return;
	}
	var dl1 = $('<dl/>');
	var dl2 = $('<dl/>');

	var split_index = toc_items.length / 2 + 1;
	if (split_index < 8) {
	split_index = toc_items.length;
	}
	for (var i = 0; i < split_index; i++) {
	dl1.append(toc_items[i]);
	}
	for (; /* keep using i */ i < toc_items.length; i++) {
	dl2.append(toc_items[i]);
	}

	var tocTable = $('<table class="unruled"/>').appendTo(nav);
	var tocBody = $('<tbody/>').appendTo(tocTable);
	var tocRow = $('<tr/>').appendTo(tocBody);

	// 1st column
	$('<td class="first"/>')
	.appendTo(tocRow)
	.append(dl1);
	// 2nd column
	$('<td/>')
	.appendTo(tocRow)
	.append(dl2);
	}

	function bindToggle(el) {
	$('.toggleButton', el).click(function() {
	if ($(this).closest('.toggle, .toggleVisible')[0] != el) {
	// Only trigger the closest toggle header.
	return;
	}

	if ($(el).is('.toggle')) {
	$(el)
	.addClass('toggleVisible')
	.removeClass('toggle');
	} else {
	$(el)
	.addClass('toggle')
	.removeClass('toggleVisible');
	}
	});
	}

	function bindToggles(selector) {
	$(selector).each(function(i, el) {
	bindToggle(el);
	});
	}

	function bindToggleLink(el, prefix) {
	$(el).click(function() {
	var href = $(el).attr('href');
	var i = href.indexOf('#' + prefix);
	if (i < 0) {
	return;
	}
	var id = '#' + prefix + href.slice(i + 1 + prefix.length);
	if ($(id).is('.toggle')) {
	$(id)
	.find('.toggleButton')
	.first()
	.click();
	}
	});
	}
	function bindToggleLinks(selector, prefix) {
	$(selector).each(function(i, el) {
	bindToggleLink(el, prefix);
	});
	}

	function setupDropdownPlayground() {
	if (!$('#page').is('.wide')) {
	return; // don't show on front page
	}
	var button = $('#playgroundButton');
	var div = $('#playground');
	var setup = false;
	button.toggle(
	function() {
	button.addClass('active');
	div.show();
	if (setup) {
	return;
	}
	setup = true;
	playground({
	codeEl: $('.code', div),
	outputEl: $('.output', div),
	runEl: $('.run', div),
	fmtEl: $('.fmt', div),
	shareEl: $('.share', div),
	shareRedirect: '//play.golang.org/p/',
	});
	},
	function() {
	button.removeClass('active');
	div.hide();
	}
	);
	$('#menu').css('min-width', '+=60');

	// Hide inline playground if we click somewhere on the page.
	// This is needed in mobile devices, where the "Play" button
	// is not clickable once the playground opens up.
	$('#page').click(function() {
	if (button.hasClass('active')) {
	button.click();
	}
	});
	}

	function setupInlinePlayground() {
	'use strict';
	// Set up playground when each element is toggled.
	$('div.play').each(function(i, el) {
	// Set up playground for this example.
	var setup = function() {
	var code = $('.code', el);
	playground({
	codeEl: code,
	outputEl: $('.output', el),
	runEl: $('.run', el),
	fmtEl: $('.fmt', el),
	shareEl: $('.share', el),
	shareRedirect: '//play.golang.org/p/',
	});

	// Make the code textarea resize to fit content.
	var resize = function() {
	code.height(0);
	var h = code[0].scrollHeight;
	code.height(h + 20); // minimize bouncing.
	code.closest('.input').height(h);
	};
	code.on('keydown', resize);
	code.on('keyup', resize);
	code.keyup(); // resize now.
	};

	// If example already visible, set up playground now.
	if ($(el).is(':visible')) {
	setup();
	return;
	}

	// Otherwise, set up playground when example is expanded.
	var built = false;
	$(el)
	.closest('.toggle')
	.click(function() {
	// Only set up once.
	if (!built) {
	setup();
	built = true;
	}
	});
	});
	}

	// fixFocus tries to put focus to div#page so that keyboard navigation works.
	function fixFocus() {
	var page = $('div#page');
	var topbar = $('div#topbar');
	page.css('outline', 0); // disable outline when focused
	page.attr('tabindex', -1); // and set tabindex so that it is focusable
	$(window)
	.resize(function(evt) {
	// only focus page when the topbar is at fixed position (that is, it's in
	// front of page, and keyboard event will go to the former by default.)
	// by focusing page, keyboard event will go to page so that up/down arrow,
	// space, etc. will work as expected.
	if (topbar.css('position') == 'fixed') page.focus();
	})
	.resize();
	}

	function toggleHash() {
	var id = window.location.hash.substring(1);
	// Open all of the toggles for a particular hash.
	var els = $(
	document.getElementById(id),
	$('a[name]').filter(function() {
	return $(this).attr('name') == id;
	})
	);

	while (els.length) {
	for (var i = 0; i < els.length; i++) {
	var el = $(els[i]);
	if (el.is('.toggle')) {
	el.find('.toggleButton')
	.first()
	.click();
	}
	}
	els = el.parent();
	}
	}

	function personalizeInstallInstructions() {
	var prefix = '?download=';
	var s = window.location.search;
	if (s.indexOf(prefix) != 0) {
	// No 'download' query string; detect "test" instructions from User Agent.
	if (navigator.platform.indexOf('Win') != -1) {
	$('.testUnix').hide();
	$('.testWindows').show();
	} else {
	$('.testUnix').show();
	$('.testWindows').hide();
	}
	return;
	}

	var filename = s.substr(prefix.length);
	var filenameRE = /^go1\.\d+(\.\d+)?([a-z0-9]+)?\.([a-z0-9]+)(-[a-z0-9]+)?(-osx10\.[68])?\.([a-z.]+)$/;
	var m = filenameRE.exec(filename);
	if (!m) {
	// Can't interpret file name; bail.
	return;
	}
	$('.downloadFilename').text(filename);
	$('.hideFromDownload').hide();

	var os = m[3];
	var ext = m[6];
	if (ext != 'tar.gz') {
	$('#tarballInstructions').hide();
	}
	if (os != 'darwin' \|\| ext != 'pkg') {
	$('#darwinPackageInstructions').hide();
	}
	if (os != 'windows') {
	$('#windowsInstructions').hide();
	$('.testUnix').show();
	$('.testWindows').hide();
	} else {
	if (ext != 'msi') {
	$('#windowsInstallerInstructions').hide();
	}
	if (ext != 'zip') {
	$('#windowsZipInstructions').hide();
	}
	$('.testUnix').hide();
	$('.testWindows').show();
	}

	var download = 'https://dl.google.com/go/' + filename;

	var message = $(
	'<p class="downloading">' +
	'Your download should begin shortly. ' +
	'If it does not, click <a>this link</a>.</p>'
	);
	message.find('a').attr('href', download);
	message.insertAfter('#nav');

	window.location = download;
	}

	function updateVersionTags() {
	var v = window.goVersion;
	if (/^go[0-9.]+$/.test(v)) {
	$('.versionTag')
	.empty()
	.text(v);
	$('.whereTag').hide();
	}
	}

	function addPermalinks() {
	function addPermalink(source, parent) {
	var id = source.attr('id');
	if (id == '' \|\| id.indexOf('tmp_') === 0) {
	// Auto-generated permalink.
	return;
	}
	if (parent.find('> .permalink').length) {
	// Already attached.
	return;
	}
	parent
	.append(' ')
	.append($("<a class='permalink'>¶</a>").attr('href', '#' + id));
	}

	$('#page .container')
	.find('h2[id], h3[id]')
	.each(function() {
	var el = $(this);
	addPermalink(el, el);
	});

	$('#page .container')
	.find('dl[id]')
	.each(function() {
	var el = $(this);
	// Add the anchor to the "dt" element.
	addPermalink(el, el.find('> dt').first());
	});
	}

	$('.js-expandAll').click(function() {
	if ($(this).hasClass('collapsed')) {
	toggleExamples('toggle');
	$(this).text('(Collapse All)');
	} else {
	toggleExamples('toggleVisible');
	$(this).text('(Expand All)');
	}
	$(this).toggleClass('collapsed');
	});

	function toggleExamples(className) {
	// We need to explicitly iterate through divs starting with "example_"
	// to avoid toggling Overview and Index collapsibles.
	$("[id^='example_']").each(function() {
	// Check for state and click it only if required.
	if ($(this).hasClass(className)) {
	$(this)
	.find('.toggleButton')
	.first()
	.click();
	}
	});
	}

	$(document).ready(function() {
	generateTOC();
	addPermalinks();
	bindToggles('.toggle');
	bindToggles('.toggleVisible');
	bindToggleLinks('.exampleLink', 'example_');
	bindToggleLinks('.overviewLink', '');
	bindToggleLinks('.examplesLink', '');
	bindToggleLinks('.indexLink', '');
	setupDropdownPlayground();
	setupInlinePlayground();
	fixFocus();
	setupTypeInfo();
	setupCallgraphs();
	toggleHash();
	personalizeInstallInstructions();
	updateVersionTags();

	// godoc.html defines window.initFuncs in the <head> tag, and root.html and
	// codewalk.js push their on-page-ready functions to the list.
	// We execute those functions here, to avoid loading jQuery until the page
	// content is loaded.
	for (var i = 0; i < window.initFuncs.length; i++) window.initFuncs[i]();
	});

	// -- analysis ---------------------------------------------------------

	// escapeHTML returns HTML for s, with metacharacters quoted.
	// It is safe for use in both elements and attributes
	// (unlike the "set innerText, read innerHTML" trick).
	function escapeHTML(s) {
	return s
	.replace(/&/g, '&')
	.replace(/\"/g, '"')
	.replace(/\'/g, ''')
	.replace(/</g, '<')
	.replace(/>/g, '>');
	}

	// makeAnchor returns HTML for an <a> element, given an anchorJSON object.
	function makeAnchor(json) {
	var html = escapeHTML(json.Text);
	if (json.Href != '') {
	html = "<a href='" + escapeHTML(json.Href) + "'>" + html + '</a>';
	}
	return html;
	}

	function showLowFrame(html) {
	var lowframe = document.getElementById('lowframe');
	lowframe.style.height = '200px';
	lowframe.innerHTML =
	"<p style='text-align: left;'>" +
	html +
	'</p>\n' +
	"<div onclick='hideLowFrame()' style='position: absolute; top: 0; right: 0; cursor: pointer;'>✘</div>";
	}

	document.hideLowFrame = function() {
	var lowframe = document.getElementById('lowframe');
	lowframe.style.height = '0px';
	};

	// onClickCallers is the onclick action for the 'func' tokens of a
	// function declaration.
	document.onClickCallers = function(index) {
	var data = document.ANALYSIS_DATA[index];
	if (data.Callers.length == 1 && data.Callers[0].Sites.length == 1) {
	document.location = data.Callers[0].Sites[0].Href; // jump to sole caller
	return;
	}

	var html =
	'Callers of <code>' + escapeHTML(data.Callee) + '</code>:<br/>\n';
	for (var i = 0; i < data.Callers.length; i++) {
	var caller = data.Callers[i];
	html += '<code>' + escapeHTML(caller.Func) + '</code>';
	var sites = caller.Sites;
	if (sites != null && sites.length > 0) {
	html += ' at line ';
	for (var j = 0; j < sites.length; j++) {
	if (j > 0) {
	html += ', ';
	}
	html += '<code>' + makeAnchor(sites[j]) + '</code>';
	}
	}
	html += '<br/>\n';
	}
	showLowFrame(html);
	};

	// onClickCallees is the onclick action for the '(' token of a function call.
	document.onClickCallees = function(index) {
	var data = document.ANALYSIS_DATA[index];
	if (data.Callees.length == 1) {
	document.location = data.Callees[0].Href; // jump to sole callee
	return;
	}

	var html = 'Callees of this ' + escapeHTML(data.Descr) + ':<br/>\n';
	for (var i = 0; i < data.Callees.length; i++) {
	html += '<code>' + makeAnchor(data.Callees[i]) + '</code><br/>\n';
	}
	showLowFrame(html);
	};

	// onClickTypeInfo is the onclick action for identifiers declaring a named type.
	document.onClickTypeInfo = function(index) {
	var data = document.ANALYSIS_DATA[index];
	var html =
	'Type <code>' +
	data.Name +
	'</code>: ' +
	'      <small>(size=' +
	data.Size +
	', align=' +
	data.Align +
	')</small><br/>\n';
	html += implementsHTML(data);
	html += methodsetHTML(data);
	showLowFrame(html);
	};

	// implementsHTML returns HTML for the implements relation of the
	// specified TypeInfoJSON value.
	function implementsHTML(info) {
	var html = '';
	if (info.ImplGroups != null) {
	for (var i = 0; i < info.ImplGroups.length; i++) {
	var group = info.ImplGroups[i];
	var x = '<code>' + escapeHTML(group.Descr) + '</code> ';
	for (var j = 0; j < group.Facts.length; j++) {
	var fact = group.Facts[j];
	var y = '<code>' + makeAnchor(fact.Other) + '</code>';
	if (fact.ByKind != null) {
	html += escapeHTML(fact.ByKind) + ' type ' + y + ' implements ' + x;
	} else {
	html += x + ' implements ' + y;
	}
	html += '<br/>\n';
	}
	}
	}
	return html;
	}

	// methodsetHTML returns HTML for the methodset of the specified
	// TypeInfoJSON value.
	function methodsetHTML(info) {
	var html = '';
	if (info.Methods != null) {
	for (var i = 0; i < info.Methods.length; i++) {
	html += '<code>' + makeAnchor(info.Methods[i]) + '</code><br/>\n';
	}
	}
	return html;
	}

	// onClickComm is the onclick action for channel "make" and "<-"
	// send/receive tokens.
	document.onClickComm = function(index) {
	var ops = document.ANALYSIS_DATA[index].Ops;
	if (ops.length == 1) {
	document.location = ops[0].Op.Href; // jump to sole element
	return;
	}

	var html = 'Operations on this channel:<br/>\n';
	for (var i = 0; i < ops.length; i++) {
	html +=
	makeAnchor(ops[i].Op) +
	' by <code>' +
	escapeHTML(ops[i].Fn) +
	'</code><br/>\n';
	}
	if (ops.length == 0) {
	html += '(none)<br/>\n';
	}
	showLowFrame(html);
	};

	$(window).load(function() {
	// Scroll window so that first selection is visible.
	// (This means we don't need to emit id='L%d' spans for each line.)
	// TODO(adonovan): ideally, scroll it so that it's under the pointer,
	// but I don't know how to get the pointer y coordinate.
	var elts = document.getElementsByClassName('selection');
	if (elts.length > 0) {
	elts[0].scrollIntoView();
	}
	});

	// setupTypeInfo populates the "Implements" and "Method set" toggle for
	// each type in the package doc.
	function setupTypeInfo() {
	for (var i in document.ANALYSIS_DATA) {
	var data = document.ANALYSIS_DATA[i];

	var el = document.getElementById('implements-' + i);
	if (el != null) {
	// el != null => data is TypeInfoJSON.
	if (data.ImplGroups != null) {
	el.innerHTML = implementsHTML(data);
	el.parentNode.parentNode.style.display = 'block';
	}
	}

	var el = document.getElementById('methodset-' + i);
	if (el != null) {
	// el != null => data is TypeInfoJSON.
	if (data.Methods != null) {
	el.innerHTML = methodsetHTML(data);
	el.parentNode.parentNode.style.display = 'block';
	}
	}
	}
	}

	function setupCallgraphs() {
	if (document.CALLGRAPH == null) {
	return;
	}
	document.getElementById('pkg-callgraph').style.display = 'block';

	var treeviews = document.getElementsByClassName('treeview');
	for (var i = 0; i < treeviews.length; i++) {
	var tree = treeviews[i];
	if (tree.id == null \|\| tree.id.indexOf('callgraph-') != 0) {
	continue;
	}
	var id = tree.id.substring('callgraph-'.length);
	$(tree).treeview({ collapsed: true, animated: 'fast' });
	document.cgAddChildren(tree, tree, [id]);
	tree.parentNode.parentNode.style.display = 'block';
	}
	}

	document.cgAddChildren = function(tree, ul, indices) {
	if (indices != null) {
	for (var i = 0; i < indices.length; i++) {
	var li = cgAddChild(tree, ul, document.CALLGRAPH[indices[i]]);
	if (i == indices.length - 1) {
	$(li).addClass('last');
	}
	}
	}
	$(tree).treeview({ animated: 'fast', add: ul });
	};

	// cgAddChild adds an <li> element for document.CALLGRAPH node cgn to
	// the parent <ul> element ul. tree is the tree's root <ul> element.
	function cgAddChild(tree, ul, cgn) {
	var li = document.createElement('li');
	ul.appendChild(li);
	li.className = 'closed';

	var code = document.createElement('code');

	if (cgn.Callees != null) {
	$(li).addClass('expandable');

	// Event handlers and innerHTML updates don't play nicely together,
	// hence all this explicit DOM manipulation.
	var hitarea = document.createElement('div');
	hitarea.className = 'hitarea expandable-hitarea';
	li.appendChild(hitarea);

	li.appendChild(code);

	var childUL = document.createElement('ul');
	li.appendChild(childUL);
	childUL.setAttribute('style', 'display: none;');

	var onClick = function() {
	document.cgAddChildren(tree, childUL, cgn.Callees);
	hitarea.removeEventListener('click', onClick);
	};
	hitarea.addEventListener('click', onClick);
	} else {
	li.appendChild(code);
	}
	code.innerHTML += ' ' + makeAnchor(cgn.Func);
	return li;
	}
	})();