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/*
* Copyright (C) 2015 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. ``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
* 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.
*/
#pragma once
#include <wtf/RefCountable.h>
#include <wtf/RefPtr.h>
#include <wtf/ThreadSafeRefCounted.h>
namespace WTF {
// Box<T> is a reference-counted pointer to T that allocates T using FastMalloc and prepends a reference
// count to it. It's almost just RefPtr<RefCountable<T>>, but has convenience operators.
template<typename T>
class Box {
WTF_DEPRECATED_MAKE_FAST_ALLOCATED(Box);
public:
Box() = default;
Box(Box&&) = default;
Box(const Box&) = default;
Box(std::nullptr_t)
{
}
Box& operator=(Box&&) = default;
Box& operator=(const Box&) = default;
template<typename... Arguments>
static Box create(Arguments&&... arguments)
{
Box result;
result.m_data = RefCountable<T>::create(std::forward<Arguments>(arguments)...);
return result;
}
bool isValid() const { return static_cast<bool>(m_data); }
T* get() const LIFETIME_BOUND
{
if (!isValid())
return nullptr;
return &**m_data;
}
T& operator*() const LIFETIME_BOUND { RELEASE_ASSERT(isValid()); return **m_data; }
T* operator->() const LIFETIME_BOUND { RELEASE_ASSERT(isValid()); return &**m_data; }
explicit operator bool() const { return isValid(); }
private:
RefPtr<RefCountable<T>> m_data;
};
} // namespace WTF
using WTF::Box;
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