82 lines
2.5 KiB
C++
82 lines
2.5 KiB
C++
/*
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* Copyright (C) 2015 Apple Inc. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
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* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
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* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#pragma once
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#include <wtf/RefPtr.h>
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#include <wtf/ThreadSafeRefCounted.h>
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namespace WTF {
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// Box<T> is a reference-counted pointer to T that allocates T using FastMalloc and prepends a reference
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// count to it.
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template<typename T>
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class Box {
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WTF_MAKE_FAST_ALLOCATED;
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public:
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Box() = default;
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Box(Box&&) = default;
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Box(const Box&) = default;
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Box(std::nullptr_t)
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{
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}
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Box& operator=(Box&&) = default;
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Box& operator=(const Box&) = default;
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template<typename... Arguments>
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static Box create(Arguments&&... arguments)
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{
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Box result;
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result.m_data = adoptRef(new Data(std::forward<Arguments>(arguments)...));
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return result;
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}
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T* get() const { return &m_data->value; }
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T& operator*() const { return m_data->value; }
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T* operator->() const { return &m_data->value; }
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explicit operator bool() const { return static_cast<bool>(m_data); }
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private:
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struct Data : ThreadSafeRefCounted<Data> {
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template<typename... Arguments>
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Data(Arguments&&... arguments)
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: value(std::forward<Arguments>(arguments)...)
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{
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}
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T value;
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};
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RefPtr<Data> m_data;
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};
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} // namespace WTF
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using WTF::Box;
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