app/assets/javascripts/ext/src/util/History.js
/*!
* Ext JS Library 3.3.0
* Copyright(c) 2006-2010 Ext JS, Inc.
* licensing@extjs.com
* http://www.extjs.com/license
*/
/**
* @class Ext.History
* @extends Ext.util.Observable
* History management component that allows you to register arbitrary tokens that signify application
* history state on navigation actions. You can then handle the history {@link #change} event in order
* to reset your application UI to the appropriate state when the user navigates forward or backward through
* the browser history stack.
* @singleton
*/
Ext.History = (function () {
var iframe, hiddenField;
var ready = false;
var currentToken;
function getHash() {
var href = location.href, i = href.indexOf("#");
return i >= 0 ? href.substr(i + 1) : null;
}
function doSave() {
hiddenField.value = currentToken;
}
function handleStateChange(token) {
currentToken = token;
Ext.History.fireEvent('change', token);
}
function updateIFrame (token) {
var html = ['<html><body><div id="state">',Ext.util.Format.htmlEncode(token),'</div></body></html>'].join('');
try {
var doc = iframe.contentWindow.document;
doc.open();
doc.write(html);
doc.close();
return true;
} catch (e) {
return false;
}
}
function checkIFrame() {
if (!iframe.contentWindow || !iframe.contentWindow.document) {
setTimeout(checkIFrame, 10);
return;
}
var doc = iframe.contentWindow.document;
var elem = doc.getElementById("state");
var token = elem ? elem.innerText : null;
var hash = getHash();
setInterval(function () {
doc = iframe.contentWindow.document;
elem = doc.getElementById("state");
var newtoken = elem ? elem.innerText : null;
var newHash = getHash();
if (newtoken !== token) {
token = newtoken;
handleStateChange(token);
top.location.hash = token;
hash = token;
doSave();
} else if (newHash !== hash) {
hash = newHash;
updateIFrame(newHash);
}
}, 50);
ready = true;
Ext.History.fireEvent('ready', Ext.History);
}
function startUp() {
currentToken = hiddenField.value ? hiddenField.value : getHash();
if (Ext.isIE) {
checkIFrame();
} else {
var hash = getHash();
setInterval(function () {
var newHash = getHash();
if (newHash !== hash) {
hash = newHash;
handleStateChange(hash);
doSave();
}
}, 50);
ready = true;
Ext.History.fireEvent('ready', Ext.History);
}
}
return {
/**
* The id of the hidden field required for storing the current history token.
* @type String
* @property
*/
fieldId: 'x-history-field',
/**
* The id of the iframe required by IE to manage the history stack.
* @type String
* @property
*/
iframeId: 'x-history-frame',
events:{},
/**
* Initialize the global History instance.
* @param {Boolean} onReady (optional) A callback function that will be called once the history
* component is fully initialized.
* @param {Object} scope (optional) The scope (<code>this</code> reference) in which the callback is executed. Defaults to the browser window.
*/
init: function (onReady, scope) {
if(ready) {
Ext.callback(onReady, scope, [this]);
return;
}
if(!Ext.isReady){
Ext.onReady(function(){
Ext.History.init(onReady, scope);
});
return;
}
hiddenField = Ext.getDom(Ext.History.fieldId);
if (Ext.isIE) {
iframe = Ext.getDom(Ext.History.iframeId);
}
this.addEvents(
/**
* @event ready
* Fires when the Ext.History singleton has been initialized and is ready for use.
* @param {Ext.History} The Ext.History singleton.
*/
'ready',
/**
* @event change
* Fires when navigation back or forwards within the local page's history occurs.
* @param {String} token An identifier associated with the page state at that point in its history.
*/
'change'
);
if(onReady){
this.on('ready', onReady, scope, {single:true});
}
startUp();
},
/**
* Add a new token to the history stack. This can be any arbitrary value, although it would
* commonly be the concatenation of a component id and another id marking the specifc history
* state of that component. Example usage:
* <pre><code>
// Handle tab changes on a TabPanel
tabPanel.on('tabchange', function(tabPanel, tab){
Ext.History.add(tabPanel.id + ':' + tab.id);
});
</code></pre>
* @param {String} token The value that defines a particular application-specific history state
* @param {Boolean} preventDuplicates When true, if the passed token matches the current token
* it will not save a new history step. Set to false if the same state can be saved more than once
* at the same history stack location (defaults to true).
*/
add: function (token, preventDup) {
if(preventDup !== false){
if(this.getToken() == token){
return true;
}
}
if (Ext.isIE) {
return updateIFrame(token);
} else {
top.location.hash = token;
return true;
}
},
/**
* Programmatically steps back one step in browser history (equivalent to the user pressing the Back button).
*/
back: function(){
history.go(-1);
},
/**
* Programmatically steps forward one step in browser history (equivalent to the user pressing the Forward button).
*/
forward: function(){
history.go(1);
},
/**
* Retrieves the currently-active history token.
* @return {String} The token
*/
getToken: function() {
return ready ? currentToken : getHash();
}
};
})();
Ext.apply(Ext.History, new Ext.util.Observable());