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332
#pma/js/microhistory.js
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332
#pma/js/microhistory.js
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/* vim: set expandtab sw=4 ts=4 sts=4: */
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/**
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* An implementation of a client-side page cache.
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* This object also uses the cache to provide a simple microhistory,
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* that is the ability to use the back and forward buttons in the browser
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*/
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PMA_MicroHistory = {
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/**
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* @var int The maximum number of pages to keep in the cache
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*/
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MAX: 6,
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/**
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* @var object A hash used to prime the cache with data about the initially
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* loaded page. This is set in the footer, and then loaded
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* by a double-queued event further down this file.
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*/
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primer: {},
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/**
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* @var array Stores the content of the cached pages
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*/
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pages: [],
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/**
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* @var int The index of the currently loaded page
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* This is used to know at which point in the history we are
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*/
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current: 0,
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/**
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* Saves a new page in the cache
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*
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* @param string hash The hash part of the url that is being loaded
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* @param array scripts A list of scripts that is required for the page
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* @param string menu A hash that links to a menu stored
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* in a dedicated menu cache
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* @param array params A list of parameters used by PMA_commonParams()
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* @param string rel A relationship to the current page:
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* 'samepage': Forces the response to be treated as
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* the same page as the current one
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* 'newpage': Forces the response to be treated as
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* a new page
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* undefined: Default behaviour, 'samepage' if the
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* selflinks of the two pages are the same.
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* 'newpage' otherwise
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*
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* @return void
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*/
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add: function (hash, scripts, menu, params, rel) {
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if (this.pages.length > PMA_MicroHistory.MAX) {
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// Trim the cache, to the maximum number of allowed entries
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// This way we will have a cached menu for every page
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for (var i = 0; i < this.pages.length - this.MAX; i++) {
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delete this.pages[i];
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}
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}
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while (this.current < this.pages.length) {
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// trim the cache if we went back in the history
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// and are now going forward again
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this.pages.pop();
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}
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if (rel === 'newpage' ||
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(
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typeof rel === 'undefined' && (
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typeof this.pages[this.current - 1] === 'undefined' ||
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this.pages[this.current - 1].hash !== hash
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)
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)
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) {
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this.pages.push({
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hash: hash,
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content: $('#page_content').html(),
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scripts: scripts,
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selflink: $('#selflink').html(),
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menu: menu,
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params: params
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});
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PMA_SetUrlHash(this.current, hash);
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this.current++;
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}
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},
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/**
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* Restores a page from the cache. This is called when the hash
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* part of the url changes and it's structure appears to be valid
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*
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* @param string index Which page from the history to load
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*
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* @return void
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*/
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navigate: function (index) {
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if (typeof this.pages[index] === 'undefined' ||
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typeof this.pages[index].content === 'undefined' ||
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typeof this.pages[index].menu === 'undefined' ||
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! PMA_MicroHistory.menus.get(this.pages[index].menu)
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) {
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PMA_ajaxShowMessage(
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'<div class="error">' + PMA_messages.strInvalidPage + '</div>',
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false
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);
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} else {
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AJAX.active = true;
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var record = this.pages[index];
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AJAX.scriptHandler.reset(function () {
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$('#page_content').html(record.content);
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$('#selflink').html(record.selflink);
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PMA_MicroHistory.menus.replace(PMA_MicroHistory.menus.get(record.menu));
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PMA_commonParams.setAll(record.params);
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AJAX.scriptHandler.load(record.scripts);
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PMA_MicroHistory.current = ++index;
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});
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}
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},
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/**
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* Resaves the content of the current page in the cache.
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* Necessary in order not to show the user some outdated version of the page
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*
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* @return void
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*/
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update: function () {
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var page = this.pages[this.current - 1];
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if (page) {
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page.content = $('#page_content').html();
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}
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},
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/**
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* @var object Dedicated menu cache
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*/
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menus: {
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/**
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* Returns the number of items in an associative array
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*
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* @return int
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*/
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size: function (obj) {
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var size = 0, key;
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for (key in obj) {
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if (obj.hasOwnProperty(key)) {
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size++;
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}
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}
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return size;
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},
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/**
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* @var hash Stores the content of the cached menus
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*/
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data: {},
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/**
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* Saves a new menu in the cache
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*
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* @param string hash The hash (trimmed md5) of the menu to be saved
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* @param string content The HTML code of the menu to be saved
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*
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* @return void
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*/
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add: function (hash, content) {
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if (this.size(this.data) > PMA_MicroHistory.MAX) {
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// when the cache grows, we remove the oldest entry
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var oldest, key, init = 0;
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for (var i in this.data) {
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if (this.data[i]) {
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if (! init || this.data[i].timestamp.getTime() < oldest.getTime()) {
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oldest = this.data[i].timestamp;
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key = i;
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init = 1;
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}
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}
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}
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delete this.data[key];
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}
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this.data[hash] = {
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content: content,
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timestamp: new Date()
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};
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},
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/**
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* Retrieves a menu given its hash
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*
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* @param string hash The hash of the menu to be retrieved
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*
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* @return string
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*/
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get: function (hash) {
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if (this.data[hash]) {
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return this.data[hash].content;
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} else {
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// This should never happen as long as the number of stored menus
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// is larger or equal to the number of pages in the page cache
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return '';
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}
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},
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/**
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* Prepares part of the parameter string used during page requests,
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* this is necessary to tell the server which menus we have in the cache
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*
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* @return string
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*/
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getRequestParam: function () {
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var param = '';
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var menuHashes = [];
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for (var i in this.data) {
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menuHashes.push(i);
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}
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var menuHashesParam = menuHashes.join('-');
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if (menuHashesParam) {
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param = '&menuHashes=' + menuHashesParam;
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}
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return param;
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},
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/**
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* Replaces the menu with new content
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*
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* @return void
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*/
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replace: function (content) {
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$('#floating_menubar').html(content)
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// Remove duplicate wrapper
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// TODO: don't send it in the response
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.children().first().remove();
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$('#topmenu').menuResizer(PMA_mainMenuResizerCallback);
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}
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}
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};
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/**
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* URL hash management module.
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* Allows direct bookmarking and microhistory.
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*/
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PMA_SetUrlHash = (function (jQuery, window) {
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"use strict";
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/**
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* Indictaes whether we have already completed
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* the initialisation of the hash
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*
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* @access private
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*/
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var ready = false;
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/**
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* Stores a hash that needed to be set when we were not ready
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*
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* @access private
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*/
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var savedHash = "";
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/**
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* Flag to indicate if the change of hash was triggered
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* by a user pressing the back/forward button or if
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* the change was triggered internally
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*
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* @access private
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*/
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var userChange = true;
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// Fix favicon disappearing in Firefox when setting location.hash
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function resetFavicon() {
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if (navigator.userAgent.indexOf('Firefox') > -1) {
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// Move the link tags for the favicon to the bottom
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// of the head element to force a reload of the favicon
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$('head > link[href=favicon\\.ico]').appendTo('head');
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}
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}
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/**
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* Sets the hash part of the URL
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*
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* @access public
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*/
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function setUrlHash(index, hash) {
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/*
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* Known problem:
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* Setting hash leads to reload in webkit:
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* http://www.quirksmode.org/bugreports/archives/2005/05/Safari_13_visual_anomaly_with_windowlocationhref.html
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*
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* so we expect that users are not running an ancient Safari version
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*/
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userChange = false;
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if (ready) {
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window.location.hash = "PMAURL-" + index + ":" + hash;
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resetFavicon();
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} else {
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savedHash = "PMAURL-" + index + ":" + hash;
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}
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}
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/**
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* Start initialisation
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*/
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var urlhash = window.location.hash;
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if (urlhash.substring(0, 8) == '#PMAURL-') {
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// We have a valid hash, let's redirect the user
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// to the page that it's pointing to
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var colon_position = urlhash.indexOf(':');
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var questionmark_position = urlhash.indexOf('?');
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if (colon_position != -1 && questionmark_position != -1 && colon_position < questionmark_position) {
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var hash_url = urlhash.substring(colon_position + 1, questionmark_position);
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if (PMA_gotoWhitelist.indexOf(hash_url) != -1) {
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window.location = urlhash.substring(
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colon_position + 1
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);
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}
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}
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} else {
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// We don't have a valid hash, so we'll set it up
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// when the page finishes loading
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jQuery(function () {
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/* Check if we should set URL */
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if (savedHash !== "") {
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window.location.hash = savedHash;
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savedHash = "";
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resetFavicon();
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}
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// Indicate that we're done initialising
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ready = true;
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});
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}
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/**
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* Register an event handler for when the url hash changes
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*/
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jQuery(function () {
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jQuery(window).hashchange(function () {
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if (userChange === false) {
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// Ignore internally triggered hash changes
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userChange = true;
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} else if (/^#PMAURL-\d+:/.test(window.location.hash)) {
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// Change page if the hash changed was triggered by a user action
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var index = window.location.hash.substring(
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8, window.location.hash.indexOf(':')
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);
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PMA_MicroHistory.navigate(index);
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}
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});
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});
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/**
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* Publicly exposes a reference to the otherwise private setUrlHash function
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*/
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return setUrlHash;
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})(jQuery, window);
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