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/*
* HTML limitations:
* - 5MB in FF and Safari, 10MB in IE 8
* - only FF 3.5 recovers session storage after a browser crash
*
* Thoughts:
* - how can we not use cookies to handle session
*/
(function() {
// internal shorthand
var Util = YAHOO.util,
Lang = YAHOO.lang,
/*
* Required for IE 8 to make synchronous.
*/
_beginTransaction = function(driver) {
driver.begin();
},
/*
* Required for IE 8 to make synchronous.
*/
_commitTransaction = function(driver) {
driver.commit();
},
/**
* The StorageEngineHTML5 class implements the HTML5 storage engine.
* @namespace YAHOO.util
* @class StorageEngineHTML5
* @constructor
* @extend YAHOO.util.Storage
* @param sLocation {String} Required. The storage location.
* @param oConf {Object} Required. A configuration object.
*/
StorageEngineHTML5 = function(sLocation, oConf) {
var that = this,
oDriver = window[sLocation];
StorageEngineHTML5.superclass.constructor.call(that, sLocation, StorageEngineHTML5.ENGINE_NAME, oConf);// not set, are cookies available
// simplifieds the begin/commit functions, if not using IE; this provides a massive performance boost
if (! oDriver.begin) {_beginTransaction = function() {}; }
if (! oDriver.commit) {_commitTransaction = function() {}; }
that.length = oDriver.length;
that._driver = oDriver;
that.fireEvent(Util.Storage.CE_READY);
};
Lang.extend(StorageEngineHTML5, Util.Storage, {
_driver: null,
/*
* Implementation to clear the values from the storage engine.
* @see YAHOO.util.Storage._clear
*/
_clear: function() {
var that = this, i, sKey;
if (that._driver.clear) {
that._driver.clear();
}
// for FF 3, fixed in FF 3.5
else {
for (i = that.length; 0 <= i; i -= 1) {
sKey = that._key(i);
that._removeItem(sKey);
}
}
},
/*
* Implementation to fetch an item from the storage engine.
* @see YAHOO.util.Storage._getItem
*/
_getItem: function(sKey) {
var o = this._driver.getItem(sKey);
return Lang.isObject(o) ? o.value : o; // for FF 3, fixed in FF 3.5
},
/*
* Implementation to fetch a key from the storage engine.
* @see YAHOO.util.Storage._key
*/
_key: function(nIndex) {return this._driver.key(nIndex);},
/*
* Implementation to remove an item from the storage engine.
* @see YAHOO.util.Storage._removeItem
*/
_removeItem: function(sKey) {
var oDriver = this._driver;
_beginTransaction(oDriver);
oDriver.removeItem(sKey);
_commitTransaction(oDriver);
this.length = oDriver.length;
},
/*
* Implementation to remove an item from the storage engine.
* @see YAHOO.util.Storage._setItem
*/
_setItem: function(sKey, oValue) {
var oDriver = this._driver;
try {
_beginTransaction(oDriver);
oDriver.setItem(sKey, oValue);
_commitTransaction(oDriver);
this.length = oDriver.length;
return true;
}
catch (e) {
return false;
}
}
}, true);
StorageEngineHTML5.ENGINE_NAME = 'html5';
StorageEngineHTML5.isAvailable = function() {
try {
return ('localStorage' in window) && window['localStorage'] !== null &&
('sessionStorage' in window) && window['sessionStorage'] !== null;
}
catch (e) {
/*
In FireFox and maybe other browsers, you can disable storage in the configuration settings, which
will cause an error to be thrown instead of evaluating the simple if/else statement.
*/
return false;
}
};
Util.StorageManager.register(StorageEngineHTML5);
Util.StorageEngineHTML5 = StorageEngineHTML5;
}());