Proyectos de Subversion Moodle

YUI.add('cache-offline', function (Y, NAME) {

/**

 * Provides a Cache subclass which uses HTML5 `localStorage` for persistence.

 *

 * @module cache

 * @submodule cache-offline

 */

/**

 * Extends Cache utility with offline functionality.

 * @class CacheOffline

 * @extends Cache

 * @constructor

 */

function CacheOffline() {

    CacheOffline.superclass.constructor.apply(this, arguments);

}

var localStorage = null,

    JSON = Y.JSON;

// Bug 2529572

try {

    localStorage = Y.config.win.localStorage;

}

catch(e) {

    Y.log("Could not access localStorage.", "warn", "cache");

}

/////////////////////////////////////////////////////////////////////////////

//

// CacheOffline events

//

/////////////////////////////////////////////////////////////////////////////

/**

* @event error

* @description Fired when an entry could not be added, most likely due to

* exceeded browser quota.

* <dl>

* <dt>error (Object)</dt> <dd>The error object.</dd>

* </dl>

*/

/////////////////////////////////////////////////////////////////////////////

//

// CacheOffline static

//

/////////////////////////////////////////////////////////////////////////////

Y.mix(CacheOffline, {

    /**

     * Class name.

     *

     * @property NAME

     * @type String

     * @static

     * @final

     * @value "cacheOffline"

     */

    NAME: "cacheOffline",

    ATTRS: {

        /////////////////////////////////////////////////////////////////////////////

        //

        // CacheOffline Attributes

        //

        /////////////////////////////////////////////////////////////////////////////

        /**

        * @attribute sandbox

        * @description A string that must be passed in via the constructor.

        * This identifier is used to sandbox one cache instance's entries

        * from another. Calling the cache instance's flush and length methods

        * or get("entries") will apply to only these sandboxed entries.

        * @type String

        * @default "default"

        * @initOnly

        */

        sandbox: {

            value: "default",

            writeOnce: "initOnly"

        },

        /**

        * @attribute expires

        * @description Absolute Date when data expires or

        * relative number of milliseconds. Zero disables expiration.

        * @type Date | Number

        * @default 86400000 (one day)

        */

        expires: {

            value: 86400000

        },

        /**

        * @attribute max

        * @description Disabled.

        * @readOnly

        * @default null

        */

        max: {

            value: null,

            readOnly: true

        },

        /**

        * @attribute uniqueKeys

        * @description Always true for CacheOffline.

        * @readOnly

        * @default true

        */

        uniqueKeys: {

            value: true,

            readOnly: true,

            setter: function() {

                return true;

            }

        }

    },

    /**

     * Removes all items from all sandboxes. Useful if localStorage has

     * exceeded quota. Only supported on browsers that implement HTML 5

     * localStorage.

     *

     * @method flushAll

     * @static

     */

    flushAll: function() {

        var store = localStorage, key;

        if(store) {

            if(store.clear) {

                store.clear();

            }

            // FF2.x and FF3.0.x

            else {

                for (key in store) {

                    if (store.hasOwnProperty(key)) {

                        store.removeItem(key);

                        delete store[key];

                    }

                }

            }

            Y.log("All sandboxes of OfflineCache flushed", "info", "cache");

        }

        else {

            Y.log("Could not flush all OfflineCache sandboxes.", "warn", "cache");

        }

    }

});

Y.extend(CacheOffline, Y.Cache, localStorage ? {

/////////////////////////////////////////////////////////////////////////////

//

// Offline is supported

//

/////////////////////////////////////////////////////////////////////////////

    /////////////////////////////////////////////////////////////////////////////

    //

    // CacheOffline protected methods

    //

    /////////////////////////////////////////////////////////////////////////////

    /**

     * Always return null.

     *

     * @method _setMax

     * @protected

     */

    _setMax: function(value) {

        return null;

    },

    /**

     * Gets size.

     *

     * @method _getSize

     * @protected

     */

    _getSize: function() {

        var count = 0,

            i=0,

            l=localStorage.length;

        for(; i<l; ++i) {

            // Match sandbox id

            if(localStorage.key(i).indexOf(this.get("sandbox")) === 0) {

                count++;

            }

        }

        return count;

    },

    /**

     * Gets all entries.

     *

     * @method _getEntries

     * @protected

     */

    _getEntries: function() {

        var entries = [],

            i=0,

            l=localStorage.length,

            sandbox = this.get("sandbox");

        for(; i<l; ++i) {

            // Match sandbox id

            if(localStorage.key(i).indexOf(sandbox) === 0) {

                entries[i] = JSON.parse(localStorage.key(i).substring(sandbox.length));

            }

        }

        return entries;

    },

    /**

     * Adds entry to cache.

     *

     * @method _defAddFn

     * @param e {EventFacade} Event Facade with the following properties:

     * <dl>

     * <dt>entry (Object)</dt> <dd>The cached entry.</dd>

     * </dl>

     * @protected

     */

    _defAddFn: function(e) {

        var entry = e.entry,

            request = entry.request,

            cached = entry.cached,

            expires = entry.expires;

        // Convert Dates to msecs on the way into localStorage

        entry.cached = cached.getTime();

        entry.expires = expires ? expires.getTime() : expires;

        try {

            localStorage.setItem(this.get("sandbox")+JSON.stringify({"request":request}), JSON.stringify(entry));

            Y.log("Cached offline entry: " + Y.dump(entry), "info", "cache");

        }

        catch(error) {

            this.fire("error", {error:error});

            Y.log("Could not cache offline entry: " + Y.dump(entry) +

            " due to error: " + Y.dump(error), "warn", "cache");

        }

    },

    /**

     * Flushes cache.

     *

     * @method _defFlushFn

     * @param e {EventFacade} Event Facade object.

     * @protected

     */

    _defFlushFn: function(e) {

        var key,

            i=localStorage.length-1;

        for(; i>-1; --i) {

            // Match sandbox id

            key = localStorage.key(i);

            if(key.indexOf(this.get("sandbox")) === 0) {

                localStorage.removeItem(key);

            }

        }

    },

    /////////////////////////////////////////////////////////////////////////////

    //

    // CacheOffline public methods

    //

    /////////////////////////////////////////////////////////////////////////////

    /**

     * Adds a new entry to the cache of the format

     * {request:request, response:response, cached:cached, expires: expires}.

     *

     * @method add

     * @param request {Object} Request value must be a String or JSON.

     * @param response {Object} Response value must be a String or JSON.

     */

    /**

     * Retrieves cached object for given request, if available.

     * Returns null if there is no cache match.

     *

     * @method retrieve

     * @param request {Object} Request object.

     * @return {Object} Cached object with the properties request, response,

     * and expires, or null.

     */

    retrieve: function(request) {

        this.fire("request", {request: request});

        var entry, expires, sandboxedrequest;

        try {

            sandboxedrequest = this.get("sandbox")+JSON.stringify({"request":request});

            try {

                entry = JSON.parse(localStorage.getItem(sandboxedrequest));

            }

            catch(e) {

            }

        }

        catch(e2) {

        }

        if(entry) {

            // Convert msecs to Dates on the way out of localStorage

            entry.cached = new Date(entry.cached);

            expires = entry.expires;

            expires = !expires ? null : new Date(expires);

            entry.expires = expires;

            if(this._isMatch(request, entry)) {

                this.fire("retrieve", {entry: entry});

                Y.log("Retrieved offlinecached response: " + Y.dump(entry) +

                        " for request: " + Y.dump(request), "info", "cache");

                return entry;

            }

        }

        return null;

    }

} :

/////////////////////////////////////////////////////////////////////////////

//

// Offline is not supported

//

/////////////////////////////////////////////////////////////////////////////

{

    /**

     * Always return null.

     *

     * @method _setMax

     * @protected

     */

    _setMax: function(value) {

        return null;

    }

});

Y.CacheOffline = CacheOffline;

}, '3.18.1', {"requires": ["cache-base", "json"]});