JavaScriptCore/runtime/PutPropertySlot.h

// -*- mode: c++; c-basic-offset: 4 -*-
/*
 * Copyright (C) 2008 Apple Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
 */

#ifndef PutPropertySlot_h
#define PutPropertySlot_h

#include <wtf/Assertions.h>

namespace JSC {
    
    class JSObject;
    class JSFunction;
    
    class PutPropertySlot {
    public:
        enum Type { Uncachable, ExistingProperty, NewProperty };

        PutPropertySlot()
            : m_type(Uncachable)
            , m_base(0)
        {
        }

        void setExistingProperty(JSObject* base, size_t offset)
        {
            m_type = ExistingProperty;
            m_base = base;
            m_offset = offset;
        }

        void setNewProperty(JSObject* base, size_t offset)
        {
            m_type = NewProperty;
            m_base = base;
            m_offset = offset;
        }

        Type type() const { return m_type; }
        JSObject* base() const { return m_base; }

        bool isCacheable() const { return m_type != Uncachable; }
        size_t cachedOffset() const {
            ASSERT(isCacheable());
            return m_offset;
        }
    private:
        Type m_type;
        JSObject* m_base;
        size_t m_offset;
    };

} // namespace JSC

#endif // PutPropertySlot_h