stringobjectthatmasqueradesasundefined.h

linux下开源浏览器WebKit的源码,市面上的很多商用浏览器都是移植自WebKit

/*
 *  Copyright (C) 1999-2000 Harri Porten ([e-mail])
 *  Copyright (C) 2007, 2008 Apple Inc. All rights reserved.
 *
 *  This library 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 2 of the License, or (at your option) any later version.
 *
 *  This library 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 library; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 */

#ifndef StringObjectThatMasqueradesAsUndefined_h
#define StringObjectThatMasqueradesAsUndefined_h

#include "JSGlobalObject.h"
#include "StringObject.h"
#include "UString.h"

namespace JSC {

    // WebCore uses this to make style.filter undetectable
    class StringObjectThatMasqueradesAsUndefined : public StringObject {
    public:
        static StringObjectThatMasqueradesAsUndefined* create(ExecState* exec, const UString& string)
        {
            return new (exec) StringObjectThatMasqueradesAsUndefined(exec,
                createStructure(exec->lexicalGlobalObject()->stringPrototype()), string);
        }

    private:
        StringObjectThatMasqueradesAsUndefined(ExecState* exec, PassRefPtr<Structure> structure, const UString& string)
            : StringObject(exec, structure, string)
        {
        }

        static PassRefPtr<Structure> createStructure(JSValuePtr proto) 
        { 
            return Structure::create(proto, TypeInfo(ObjectType, MasqueradesAsUndefined)); 
        }

        virtual bool toBoolean(ExecState*) const { return false; }
    };
 
} // namespace JSC

#endif // StringObjectThatMasqueradesAsUndefined_h