easejs/lib/VisibilityObjectFactoryFactory.js

/**
 * Contains factory for visibility object factory
 *
 *  Copyright (C) 2010 Mike Gerwitz
 *
 *  This file is part of ease.js.
 *
 *  ease.js is free software: you can redistribute it and/or modify it under the
 *  terms of the GNU Lesser General Public License as published by the Free
 *  Software Foundation, either version 3 of the License, or (at your option)
 *  any later version.
 *
 *  This program is distributed in the hope that it will be useful, but WITHOUT
 *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License
 *  for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * @author  Mike Gerwitz
 * @package core
 *
 * XXX: Figure out how to resolve Closure Compiler's warning about shared type
 * information
 */

// XXX: Tightly coupled
var util = require( __dirname + '/util' ),

    VisibilityObjectFactory = require( __dirname + '/VisibilityObjectFactory' ),

    FallbackVisibilityObjectFactory =
        require( __dirname + '/FallbackVisibilityObjectFactory' )
;


/**
 * Responsible for instantiating the VisibilityObjectFactory appropriate for the
 * runtime environment
 *
 * This prototype determines what class should be instantiated. If we are within
 * an ECMAScript 5 environment, we can take full advantage of the standard
 * visibility object implementation. Otherwise, we are unable to emulate proxies
 * and must fall back on a less sophisticated implementation that sacrifices
 * visibility support.
 */
exports.fromEnvironment = function()
{
    // if falling back, return fallback, otherwise standard
    return ( util.definePropertyFallback() )
        ? FallbackVisibilityObjectFactory()
        : VisibilityObjectFactory()
    ;
};