Yahoo! UI Library

/*
 * SWF limitation:
 * 	- only 100,000 bytes of data may be stored this way
 *  - data is publicly available on user machine
 *
 * Thoughts:
 *  - data can be shared across browsers
 *  - how can we not use cookies to handle session location
 */
(function() {
	// internal shorthand
var Y = YAHOO,
    Util = Y.util,
	Lang = Y.lang,
	Dom = Util.Dom,
	StorageManager = Util.StorageManager,
	
	/*
	 * The minimum width required to be able to display the settings panel within the SWF.
	 */	
	MINIMUM_WIDTH = 215,

	/*
	 * The minimum height required to be able to display the settings panel within the SWF.
	 */	
	MINIMUM_HEIGHT = 138,

	RX_STORAGE_PREFIX = new RegExp('^(' + StorageManager.LOCATION_SESSION + '|' + StorageManager.LOCATION_LOCAL + ')'),

	// local variables
	_driver = null,

	/*
	 * Creates a location bound key.
	 */
	_getKey = function(that, sKey) {
		return that._location + sKey;
	},

	/*
	 * Initializes the engine, if it isn't already initialized.
	 */
	_initDriver = function(oCfg) {
		if (! _driver) {
			if (! Lang.isString(oCfg.swfURL)) {oCfg.swfURL = StorageEngineSWF.SWFURL;}
			if (! oCfg.containerID) {
				var bd = document.getElementsByTagName('body')[0],
					container = bd.appendChild(document.createElement('div'));
				oCfg.containerID = Dom.generateId(container);
			}

			if (! oCfg.attributes) {oCfg.attributes  = {};}
			if (! oCfg.attributes.flashVars) {oCfg.attributes.flashVars = {};}
			oCfg.attributes.flashVars.allowedDomain = document.location.hostname;
			oCfg.attributes.flashVars.useCompression = 'true';
			oCfg.attributes.version = 9.115;
			_driver = new Y.widget.SWF(oCfg.containerID, oCfg.swfURL, oCfg.attributes);

			// subscribe to save for info
			_driver.subscribe('save', function(o) {
				Y.log(o.message, 'info');
			});

			// subscribe to errors
			_driver.subscribe('quotaExceededError', function(o) {
				Y.log(o.message, 'error');
			});
			_driver.subscribe('inadequateDimensions', function(o) {
				Y.log(o.message, 'error');
			});
			_driver.subscribe('error', function(o) {
				Y.log(o.message, 'error');
			});
			_driver.subscribe('securityError', function(o) {
				Y.log(o.message, 'error');
			});
		}
	},

	/**
	 * The StorageEngineSWF class implements the SWF storage engine.
	 * @namespace YAHOO.util
	 * @class StorageEngineSWF
	 * @uses YAHOO.widget.SWF
	 * @constructor
	 * @extend YAHOO.util.Storage
	 * @param sLocation {String} Required. The storage location.
	 * @param oConf {Object} Required. A configuration object.
	 */
	StorageEngineSWF = function(sLocation, oConf) {
		var that = this;
		StorageEngineSWF.superclass.constructor.call(that, sLocation, StorageEngineSWF.ENGINE_NAME, oConf);
		
		_initDriver(that._cfg);
		
		var _onContentReady = function() {
			that._swf = _driver._swf;
			_driver.initialized = true;
			
			var isSessionStorage = StorageManager.LOCATION_SESSION === that._location,
				sessionKey = Util.Cookie.get('sessionKey' + StorageEngineSWF.ENGINE_NAME),
                i, key, isKeySessionStorage;

			for (i = _driver.callSWF("getLength", []) - 1; 0 <= i; i -= 1) {
				key = _driver.callSWF("getNameAt", [i]);
				isKeySessionStorage = isSessionStorage && (-1 < key.indexOf(StorageManager.LOCATION_SESSION));

				// this is session storage, but the session key is not set, so remove item
				if (isKeySessionStorage && ! sessionKey) {
					_driver.callSWF("removeItem", [key]);
				}
				else if (isSessionStorage === isKeySessionStorage) {
                    // the key matches the storage type, add to key collection
					that._addKey(key);
				}
			}

			// this is session storage, ensure that the session key is set
			if (isSessionStorage) {
				Util.Cookie.set('sessionKey' + StorageEngineSWF.ENGINE_NAME, true);
			}

			that.fireEvent(Util.Storage.CE_READY);
		};
		
		// evaluate immediately, SWF is already loaded
		if (_driver.initialized) {
            _onContentReady();
		}
		else {
            // evaluates when the SWF is loaded
			_driver.addListener("contentReady", _onContentReady);
		}
	};

	Lang.extend(StorageEngineSWF, Util.StorageEngineKeyed, {
		/**
		 * The underlying SWF of the engine, exposed so developers can modify the adapter behavior.
		 * @property _swf
		 * @type {Object}
		 * @protected
		 */
		_swf: null,

		/*
		 * Implementation to clear the values from the storage engine.
		 * @see YAHOO.util.Storage._clear
		 */
		_clear: function() {
			for (var i = this._keys.length - 1, sKey; 0 <= i; i -= 1) {
				sKey = this._keys[i];
				_driver.callSWF("removeItem", [sKey]);
			}
			// since keys are used to clear, we call the super function second
			StorageEngineSWF.superclass._clear.call(this);
		},

		/*
		 * Implementation to fetch an item from the storage engine.
		 * @see YAHOO.util.Storage._getItem
		 */
		_getItem: function(sKey) {
			var sLocationKey = _getKey(this, sKey);
			return _driver.callSWF("getValueOf", [sLocationKey]);
		},

		/*
		 * Implementation to fetch a key from the storage engine.
		 * @see YAHOO.util.Storage.key
		 */
		_key: function(index) {
			return StorageEngineSWF.superclass._key.call(this, index).replace(RX_STORAGE_PREFIX, '');
		},

		/*
		 * Implementation to remove an item from the storage engine.
		 * @see YAHOO.util.Storage._removeItem
		 */
		_removeItem: function(sKey) {
			Y.log("removing SWF key: " + sKey);
			var sLocationKey = _getKey(this, sKey);
			StorageEngineSWF.superclass._removeItem.call(this, sLocationKey);
			_driver.callSWF("removeItem", [sLocationKey]);
		},

		/*
		 * Implementation to remove an item from the storage engine.
		 * @see YAHOO.util.Storage._setItem
		 */
		_setItem: function(sKey, oData) {
			var sLocationKey = _getKey(this, sKey), swfNode;

			if (_driver.callSWF("setItem", [sLocationKey, oData])) {
				this._addKey(sLocationKey);
				return true;
			}
			else {
                /*
                    note:
                        right if the FLASH SLO size needs to be adjusted, then this request and all future requests fail
                        should we queue these up and poll for when there is enough space?
                 */
				swfNode = Dom.get(_driver._id);
				if (MINIMUM_WIDTH > Dom.getStyle(swfNode, 'width').replace(/\D+/g, '')) {Dom.setStyle(swfNode, 'width', MINIMUM_WIDTH + 'px');}
				if (MINIMUM_HEIGHT > Dom.getStyle(swfNode, 'height').replace(/\D+/g, '')) {Dom.setStyle(swfNode, 'height', MINIMUM_HEIGHT + 'px');}
				Y.log("attempting to show settings. are dimensions adequate? " + _driver.callSWF("hasAdequateDimensions"));
				return _driver.callSWF("displaySettings", []);
			}
		}
	});

	StorageEngineSWF.SWFURL = "swfstore.swf";
	StorageEngineSWF.ENGINE_NAME = 'swf';

    StorageEngineSWF.isAvailable = function() {
		return (6 <= Y.env.ua.flash && Y.widget.SWF);
	};

    StorageManager.register(StorageEngineSWF);
	Util.StorageEngineSWF = StorageEngineSWF;
}());