import { PMA_ajaxShowMessage } from '../utils/show_ajax_messages';
import { AJAX } from '../ajax';
import { PMA_Messages as messages } from '../variables/export_variables';
import CommonParams from '../variables/common_params';
import SetUrlHash from './SetUrlHash';
/**
* An implementation of a client-side page cache.
* This object also uses the cache to provide a simple microhistory,
* that is the ability to use the back and forward buttons in the browser
*/
var MicroHistory = {
/**
* @var int The maximum number of pages to keep in the cache
*/
MAX: 6,
/**
* @var object A hash used to prime the cache with data about the initially
* loaded page. This is set in the footer, and then loaded
* by a double-queued event further down this file.
*/
primer: {},
/**
* @var array Stores the content of the cached pages
*/
pages: [],
/**
* @var int The index of the currently loaded page
* This is used to know at which point in the history we are
*/
current: 0,
/**
* Saves a new page in the cache
*
* @param string hash The hash part of the url that is being loaded
* @param array scripts A list of scripts that is required for the page
* @param string menu A hash that links to a menu stored
* in a dedicated menu cache
* @param array params A list of parameters used by CommonParams()
* @param string rel A relationship to the current page:
* 'samepage': Forces the response to be treated as
* the same page as the current one
* 'newpage': Forces the response to be treated as
* a new page
* undefined: Default behaviour, 'samepage' if the
* selflinks of the two pages are the same.
* 'newpage' otherwise
*
* @return void
*/
add: function (hash, scripts, menu, params, rel) {
if (this.pages.length > MicroHistory.MAX) {
// Trim the cache, to the maximum number of allowed entries
// This way we will have a cached menu for every page
for (var i = 0; i < this.pages.length - this.MAX; i++) {
delete this.pages[i];
}
}
while (this.current < this.pages.length) {
// trim the cache if we went back in the history
// and are now going forward again
this.pages.pop();
}
if (rel === 'newpage' ||
(
typeof rel === 'undefined' && (
typeof this.pages[this.current - 1] === 'undefined' ||
this.pages[this.current - 1].hash !== hash
)
)
) {
this.pages.push({
hash: hash,
content: $('#page_content').html(),
scripts: scripts,
selflink: $('#selflink').html(),
menu: menu,
params: params
});
SetUrlHash(this.current, hash);
this.current++;
}
},
/**
* Restores a page from the cache. This is called when the hash
* part of the url changes and it's structure appears to be valid
*
* @param string index Which page from the history to load
*
* @return void
*/
navigate: function (index) {
if (typeof this.pages[index] === 'undefined' ||
typeof this.pages[index].content === 'undefined' ||
typeof this.pages[index].menu === 'undefined' ||
! MicroHistory.menus.get(this.pages[index].menu)
) {
PMA_ajaxShowMessage(
'<div class="error">' + messages.strInvalidPage + '</div>',
false
);
} else {
AJAX.active = true;
var record = this.pages[index];
AJAX.scriptHandler.reset(function () {
$('#page_content').html(record.content);
$('#selflink').html(record.selflink);
MicroHistory.menus.replace(MicroHistory.menus.get(record.menu));
CommonParams.setAll(record.params);
AJAX.scriptHandler.load(record.scripts);
MicroHistory.current = ++index;
});
}
},
/**
* Resaves the content of the current page in the cache.
* Necessary in order not to show the user some outdated version of the page
*
* @return void
*/
update: function () {
var page = this.pages[this.current - 1];
if (page) {
page.content = $('#page_content').html();
}
},
/**
* @var object Dedicated menu cache
*/
menus: {
/**
* Returns the number of items in an associative array
*
* @return int
*/
size: function (obj) {
var size = 0;
var key;
for (key in obj) {
if (obj.hasOwnProperty(key)) {
size++;
}
}
return size;
},
/**
* @var hash Stores the content of the cached menus
*/
data: {},
/**
* Saves a new menu in the cache
*
* @param string hash The hash (trimmed md5) of the menu to be saved
* @param string content The HTML code of the menu to be saved
*
* @return void
*/
add: function (hash, content) {
if (this.size(this.data) > MicroHistory.MAX) {
// when the cache grows, we remove the oldest entry
var oldest;
var key;
var init = 0;
for (var i in this.data) {
if (this.data[i]) {
if (! init || this.data[i].timestamp.getTime() < oldest.getTime()) {
oldest = this.data[i].timestamp;
key = i;
init = 1;
}
}
}
delete this.data[key];
}
this.data[hash] = {
content: content,
timestamp: new Date()
};
},
/**
* Retrieves a menu given its hash
*
* @param string hash The hash of the menu to be retrieved
*
* @return string
*/
get: function (hash) {
if (this.data[hash]) {
return this.data[hash].content;
} else {
// This should never happen as long as the number of stored menus
// is larger or equal to the number of pages in the page cache
return '';
}
},
/**
* Prepares part of the parameter string used during page requests,
* this is necessary to tell the server which menus we have in the cache
*
* @return string
*/
getRequestParam: function () {
var param = '';
var menuHashes = [];
for (var i in this.data) {
menuHashes.push(i);
}
var menuHashesParam = menuHashes.join('-');
if (menuHashesParam) {
param = CommonParams.get('arg_separator') + 'menuHashes=' + menuHashesParam;
}
return param;
},
/**
* Replaces the menu with new content
*
* @return void
*/
replace: function (content) {
$('#floating_menubar').html(content)
// Remove duplicate wrapper
// TODO: don't send it in the response
.children().first().remove();
$('#topmenu').menuResizer(PMA_mainMenuResizerCallback);
}
}
};
export default MicroHistory;