/*global YUI */
/*jslint onevar: true, browser: true, undef: true, bitwise: true, regexp: true, newcap: true, immed: true */
/**
* Implements a persistent local key/value data store similar to HTML5's
* localStorage. Should work in IE5+, Firefox 2+, Safari 3.1+, Chrome 4+, and
* Opera 10.5+.
*
* @module gallery-storage-lite
*/
YUI.add('gallery-storage-lite', function (Y) {
// -- Shorthand ----------------------------------------------------------------
var d = Y.config.doc,
w = Y.config.win,
JSON = Y.JSON,
StorageLite = Y.namespace('StorageLite'),
// -- Private Constants --------------------------------------------------------
DB_NAME = 'yui_storage_lite',
DB_DISPLAYNAME = 'YUI StorageLite data',
DB_MAXSIZE = 1048576,
DB_VERSION = '1.0',
EVT_READY = 'ready',
MODE_NOOP = 0,
MODE_HTML5 = 1,
MODE_GECKO = 2,
MODE_DB = 3,
MODE_USERDATA = 4,
USERDATA_PATH = 'yui_storage_lite',
USERDATA_NAME = 'data',
// -- Private Variables --------------------------------------------------------
data = {},
storageDriver,
storageMode;
// -- Implementation -----------------------------------------------------------
// Determine the best available storage mode.
if (w.localStorage) {
storageMode = MODE_HTML5;
} else if (w.globalStorage) {
storageMode = MODE_GECKO;
} else if (w.openDatabase && navigator.userAgent.indexOf('Chrome') === -1) {
storageMode = MODE_DB;
} else if (Y.UA.ie >= 5) {
storageMode = MODE_USERDATA;
} else {
storageMode = MODE_NOOP;
}
Y.StorageFullError = function (message) {
Y.StorageFullError.superclass.constructor.call(message);
this.name = 'StorageFullError';
this.message = message || 'Maximum storage capacity reached';
if (Y.UA.ie) {
this.description = this.message;
}
};
Y.extend(Y.StorageFullError, Error);
/**
* Provides a persistent local key/value data store similar to HTML5's
* localStorage.
*
* @class StorageLite
* @static
*/
// -- Public Events ------------------------------------------------------------
Y.augment(StorageLite, Y.EventTarget, true, null, {
emitFacade : true,
prefix : 'storage-lite',
preventable: false
});
/**
* Fired when the storage interface is loaded and ready for use.
*
* @event storage-lite:ready
*/
StorageLite.publish(EVT_READY, {fireOnce: true});
Y.mix(StorageLite, {
// -- Public Methods -------------------------------------------------------
/**
* Removes all items from the data store.
*
* @method clear
*/
clear: function () {},
/**
* Returns the item with the specified key, or <code>null</code> if the item
* was not found.
*
* @method getItem
* @param {String} key
* @param {bool} json (optional) <code>true</code> if the item is a JSON
* string and should be parsed before being returned
* @return {Object|null} item or <code>null</code> if not found
*/
getItem: function (key, json) { return null; },
/**
* Returns the number of items in the data store.
*
* @method length
* @return {Number} number of items in the data store
*/
length: function () { return 0; },
/**
* Removes the item with the specified key.
*
* @method removeItem
* @param {String} key
*/
removeItem: function (key) {},
/**
* Stores an item under the specified key. If the key already exists in the
* data store, it will be replaced.
*
* @method setItem
* @param {String} key
* @param {Object} value
* @param {bool} json (optional) <code>true</code> if the item should be
* serialized to a JSON string before being stored
*/
setItem: function (key, value) {}
});
if (storageMode === MODE_HTML5 || storageMode === MODE_GECKO) {
// Common methods shared by the HTML5 and Gecko implementations.
Y.mix(StorageLite, {
length: function () {
return storageDriver.length;
},
removeItem: function (key) {
storageDriver.removeItem(key);
},
setItem: function (key, value, json) {
storageDriver.setItem(key, json ? JSON.stringify(value) : value);
}
}, true);
if (storageMode === MODE_HTML5) {
// HTML5 localStorage methods. Currently supported by IE8, Firefox 3.5+,
// Safari 4+, Chrome 4+, and Opera 10.5+.
storageDriver = w.localStorage;
Y.mix(StorageLite, {
clear: function () {
storageDriver.clear();
},
getItem: function (key, json) {
try {
return json ? JSON.parse(storageDriver.getItem(key)) :
storageDriver.getItem(key);
} catch (ex) {
return null;
}
}
}, true);
} else if (storageMode === MODE_GECKO) {
// Gecko globalStorage methods. Supported by Firefox 2 and 3.0.
storageDriver = w.globalStorage[w.location.hostname];
Y.mix(StorageLite, {
clear: function () {
for (var key in storageDriver) {
if (storageDriver.hasOwnProperty(key)) {
storageDriver.removeItem(key);
delete storageDriver[key];
}
}
},
getItem: function (key, json) {
try {
return json ? JSON.parse(storageDriver[key].value) :
storageDriver[key].value;
} catch (ex) {
return null;
}
}
}, true);
}
StorageLite.fire(EVT_READY);
} else if (storageMode === MODE_DB || storageMode === MODE_USERDATA) {
// Common methods shared by the database and userdata implementations.
Y.mix(StorageLite, {
clear: function () {
data = {};
StorageLite._save();
},
getItem: function (key, json) {
return data.hasOwnProperty(key) ? data[key] : null;
},
length: function () {
var count = 0, key;
for (key in data) {
if (data.hasOwnProperty(key)) {
count += 1;
}
}
return count;
},
removeItem: function (key) {
delete data[key];
StorageLite._save();
},
setItem: function (key, value, json) {
data[key] = value;
StorageLite._save();
}
}, true);
if (storageMode === MODE_DB) {
// Database storage methods. Supported by Safari 3.1 and 3.2.
storageDriver = w.openDatabase(DB_NAME, DB_VERSION, DB_DISPLAYNAME, DB_MAXSIZE);
Y.mix(StorageLite, {
_save: function () {
storageDriver.transaction(function (t) {
t.executeSql("REPLACE INTO " + DB_NAME + " (name, value) VALUES ('data', ?)", [JSON.stringify(data)]);
});
}
}, true);
storageDriver.transaction(function (t) {
t.executeSql("CREATE TABLE IF NOT EXISTS " + DB_NAME + "(name TEXT PRIMARY KEY, value TEXT NOT NULL)");
t.executeSql("SELECT value FROM " + DB_NAME + " WHERE name = 'data'", [], function (t, results) {
if (results.rows.length) {
try {
data = JSON.parse(results.rows.item(0).value);
} catch (ex) {
data = {};
}
}
StorageLite.fire(EVT_READY);
});
});
} else if (storageMode === MODE_USERDATA) {
// userData storage methods. Supported by IE5, 6, and 7.
storageDriver = d.createElement('span');
storageDriver.addBehavior('#default#userData');
Y.mix(StorageLite, {
_save: function () {
var _data = JSON.stringify(data);
try {
storageDriver.setAttribute(USERDATA_NAME, _data);
storageDriver.save(USERDATA_PATH);
} catch (ex) {
throw new Y.StorageFullError();
}
}
}, true);
Y.on('domready', function () {
d.body.appendChild(storageDriver);
storageDriver.load(USERDATA_PATH);
try {
data = JSON.parse(storageDriver.getAttribute(USERDATA_NAME));
} catch (ex) {
data = {};
}
StorageLite.fire(EVT_READY);
});
}
} else {
// Fire the ready event for browsers that only support the noop mode.
StorageLite.fire(EVT_READY);
}
}, '1.0.0', {
requires: ['event-base', 'event-custom', 'event-custom-complex', 'json']
});