Source/wtf/ArrayBufferContents.h

/*
 * Copyright (C) 2009 Apple Inc. All rights reserved.
 * Copyright (C) 2013 Google 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 ArrayBufferContents_h
#define ArrayBufferContents_h

#include "wtf/ArrayBufferDeallocationObserver.h"
#include "wtf/Noncopyable.h"

namespace WTF {

class ArrayBufferContents {
    WTF_MAKE_NONCOPYABLE(ArrayBufferContents);
public:
    ArrayBufferContents()
        : m_data(0)
        , m_sizeInBytes(0)
        , m_deallocationObserver(0)
    { }

    ~ArrayBufferContents();

    void* data() { return m_data; }
    unsigned sizeInBytes() { return m_sizeInBytes; }

private:
    ArrayBufferContents(void* data, unsigned sizeInBytes)
        : m_data(data)
        , m_sizeInBytes(sizeInBytes)
        , m_deallocationObserver(0)
    { }

    friend class ArrayBuffer;

    enum InitializationPolicy {
        ZeroInitialize,
        DontInitialize
    };

    static void tryAllocate(unsigned numElements, unsigned elementByteSize, InitializationPolicy, ArrayBufferContents&);
    void transfer(ArrayBufferContents& other)
    {
        ASSERT(!other.m_data);
        other.m_data = m_data;
        other.m_sizeInBytes = m_sizeInBytes;
        m_data = 0;
        m_sizeInBytes = 0;
        // Notify the current V8 isolate that the buffer is gone.
        if (m_deallocationObserver)
            m_deallocationObserver->ArrayBufferDeallocated(other.m_sizeInBytes);
        ASSERT(!other.m_deallocationObserver);
        m_deallocationObserver = 0;
    }

    void* m_data;
    unsigned m_sizeInBytes;

    ArrayBufferDeallocationObserver* m_deallocationObserver;
};

} // namespace WTF

#endif // ArrayBufferContents_h