/* * Copyright (C) 2014 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 CopyWriteBarrier_h #define CopyWriteBarrier_h #include "Heap.h" namespace JSC { template <typename T> class CopyWriteBarrier { public: CopyWriteBarrier() : m_value(0) { } CopyWriteBarrier(VM& vm, const JSCell* owner, T& value) { this->set(vm, owner, &value); } CopyWriteBarrier(VM& vm, const JSCell* owner, T* value) { this->set(vm, owner, value); } bool operator!() const { return !m_value; } typedef T* (CopyWriteBarrier::*UnspecifiedBoolType); operator UnspecifiedBoolType*() const { return m_value ? reinterpret_cast<UnspecifiedBoolType*>(1) : 0; } T* get() const { return m_value; } T* operator*() const { return get(); } T* operator->() const { return get(); } void set(VM& vm, const JSCell* owner, T* value) { this->m_value = value; vm.heap.writeBarrier(owner); } void setWithoutWriteBarrier(T* value) { this->m_value = value; } void clear() { m_value = 0; } private: T* m_value; }; } // namespace JSC #endif // CopyWriteBarrier_h