Source/JavaScriptCore/runtime/StorageBarrier.h

/*
 * Copyright (C) 2011 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 INC. AND ITS CONTRIBUTORS ``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 INC. OR ITS 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 StorageBarrier_h
#define StorageBarrier_h

#include "JSGlobalData.h"
#include "WriteBarrier.h"

namespace JSC {

typedef WriteBarrierBase<Unknown>* PropertyStorage;
typedef const WriteBarrierBase<Unknown>* ConstPropertyStorage;

class StorageBarrier {
public:
    enum UncheckedTag { Unchecked };
    StorageBarrier(JSGlobalData& globalData, JSCell* owner, PropertyStorage storage)
    {
        set(globalData, owner, storage);
    }
    
    StorageBarrier(PropertyStorage storage, UncheckedTag)
    {
        set(storage, Unchecked);
    }
    
    void set(JSGlobalData&, JSCell*, PropertyStorage newStorage)
    {
        m_storage = newStorage;
    }
    
    void set(PropertyStorage newStorage, UncheckedTag)
    {
        m_storage = newStorage;
    }
    
    WriteBarrierBase<Unknown>* operator->() const { return m_storage; }
    WriteBarrierBase<Unknown>* operator->() { return m_storage; }
    WriteBarrierBase<Unknown> operator*() const { return *m_storage; }
    WriteBarrierBase<Unknown> operator*() { return *m_storage; }
    const WriteBarrierBase<Unknown>& operator[](size_t i) const { return m_storage[i]; }
    WriteBarrierBase<Unknown>& operator[](size_t i) { return m_storage[i]; }
    
    ConstPropertyStorage get() const { return m_storage; }
    PropertyStorage get() { return m_storage; }

    bool operator!() { return !m_storage; }
    
private:
    PropertyStorage m_storage;
};

}

#endif