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/*
* Copyright (C) 2006, 2007, 2008, 2009, 2010, 2014 Apple Inc. All rights reserved.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public License
* along with this library; see the file COPYING.LIB. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301, USA.
*
*/
#ifndef WTF_OwnPtr_h
#define WTF_OwnPtr_h
#include <wtf/Assertions.h>
#include <wtf/Atomics.h>
#include <wtf/Noncopyable.h>
#include <wtf/OwnPtrCommon.h>
#include <algorithm>
#include <cstddef>
#include <memory>
namespace WTF {
template<typename T> class PassOwnPtr;
template<typename T> PassOwnPtr<T> adoptPtr(T*);
template<typename T> class OwnPtr {
public:
typedef T ValueType;
typedef ValueType* PtrType;
OwnPtr() : m_ptr(0) { }
OwnPtr(std::nullptr_t) : m_ptr(0) { }
// See comment in PassOwnPtr.h for why this takes a const reference.
template<typename U> OwnPtr(const PassOwnPtr<U>& o);
~OwnPtr() { deleteOwnedPtr(m_ptr); }
PtrType get() const { return m_ptr; }
void clear();
PassOwnPtr<T> release();
PtrType leakPtr() WARN_UNUSED_RETURN;
ValueType& operator*() const { ASSERT(m_ptr); return *m_ptr; }
PtrType operator->() const { ASSERT(m_ptr); return m_ptr; }
bool operator!() const { return !m_ptr; }
// This conversion operator allows implicit conversion to bool but not to other integer types.
typedef PtrType OwnPtr::*UnspecifiedBoolType;
operator UnspecifiedBoolType() const { return m_ptr ? &OwnPtr::m_ptr : 0; }
OwnPtr& operator=(const PassOwnPtr<T>&);
OwnPtr& operator=(std::nullptr_t) { clear(); return *this; }
template<typename U> OwnPtr& operator=(const PassOwnPtr<U>&);
OwnPtr(OwnPtr&&);
template<typename U> OwnPtr(OwnPtr<U>&&);
OwnPtr& operator=(OwnPtr&&);
template<typename U> OwnPtr& operator=(OwnPtr<U>&&);
void swap(OwnPtr& o) { std::swap(m_ptr, o.m_ptr); }
// Construct an object to store into this OwnPtr, but only so long as this OwnPtr
// doesn't already point to an object. This will ensure that after you call this,
// the OwnPtr will point to an instance of T, even if called concurrently. This
// instance may or may not have been created by this call. Moreover, this call uses
// an opportunistic transaction, in that we may create an instance of T and then
// immediately throw it away, if in the process of creating that instance some
// other thread was doing the same thing and stored its instance into this pointer
// before we had a chance to do so.
template<typename... Args>
void createTransactionally(Args...);
private:
explicit OwnPtr(PtrType ptr) : m_ptr(ptr) { }
// We should never have two OwnPtrs for the same underlying object (otherwise we'll get
// double-destruction), so these equality operators should never be needed.
template<typename U> bool operator==(const OwnPtr<U>&) { COMPILE_ASSERT(!sizeof(U*), OwnPtrs_should_never_be_equal); return false; }
template<typename U> bool operator!=(const OwnPtr<U>&) { COMPILE_ASSERT(!sizeof(U*), OwnPtrs_should_never_be_equal); return false; }
template<typename U> bool operator==(const PassOwnPtr<U>&) { COMPILE_ASSERT(!sizeof(U*), OwnPtrs_should_never_be_equal); return false; }
template<typename U> bool operator!=(const PassOwnPtr<U>&) { COMPILE_ASSERT(!sizeof(U*), OwnPtrs_should_never_be_equal); return false; }
PtrType m_ptr;
};
template<typename T> template<typename U> inline OwnPtr<T>::OwnPtr(const PassOwnPtr<U>& o)
: m_ptr(o.leakPtr())
{
}
template<typename T> inline void OwnPtr<T>::clear()
{
PtrType ptr = m_ptr;
m_ptr = 0;
deleteOwnedPtr(ptr);
}
template<typename T> inline PassOwnPtr<T> OwnPtr<T>::release()
{
PtrType ptr = m_ptr;
m_ptr = 0;
return adoptPtr(ptr);
}
template<typename T> inline typename OwnPtr<T>::PtrType OwnPtr<T>::leakPtr()
{
PtrType ptr = m_ptr;
m_ptr = 0;
return ptr;
}
template<typename T> inline OwnPtr<T>& OwnPtr<T>::operator=(const PassOwnPtr<T>& o)
{
PtrType ptr = m_ptr;
m_ptr = o.leakPtr();
ASSERT(!ptr || m_ptr != ptr);
deleteOwnedPtr(ptr);
return *this;
}
template<typename T> template<typename U> inline OwnPtr<T>& OwnPtr<T>::operator=(const PassOwnPtr<U>& o)
{
PtrType ptr = m_ptr;
m_ptr = o.leakPtr();
ASSERT(!ptr || m_ptr != ptr);
deleteOwnedPtr(ptr);
return *this;
}
template<typename T> inline OwnPtr<T>::OwnPtr(OwnPtr<T>&& o)
: m_ptr(o.leakPtr())
{
}
template<typename T> template<typename U> inline OwnPtr<T>::OwnPtr(OwnPtr<U>&& o)
: m_ptr(o.leakPtr())
{
}
template<typename T> inline auto OwnPtr<T>::operator=(OwnPtr&& o) -> OwnPtr&
{
ASSERT(!o || o != m_ptr);
OwnPtr ptr = WTF::move(o);
swap(ptr);
return *this;
}
template<typename T> template<typename U> inline auto OwnPtr<T>::operator=(OwnPtr<U>&& o) -> OwnPtr&
{
ASSERT(!o || o != m_ptr);
OwnPtr ptr = WTF::move(o);
swap(ptr);
return *this;
}
template<typename T> inline void swap(OwnPtr<T>& a, OwnPtr<T>& b)
{
a.swap(b);
}
template<typename T, typename U> inline bool operator==(const OwnPtr<T>& a, U* b)
{
return a.get() == b;
}
template<typename T, typename U> inline bool operator==(T* a, const OwnPtr<U>& b)
{
return a == b.get();
}
template<typename T, typename U> inline bool operator!=(const OwnPtr<T>& a, U* b)
{
return a.get() != b;
}
template<typename T, typename U> inline bool operator!=(T* a, const OwnPtr<U>& b)
{
return a != b.get();
}
template<typename T> inline typename OwnPtr<T>::PtrType getPtr(const OwnPtr<T>& p)
{
return p.get();
}
template<typename T> template<typename... Args> inline void OwnPtr<T>::createTransactionally(Args... args)
{
if (m_ptr) {
WTF::loadLoadFence();
return;
}
T* newObject = new T(args...);
WTF::storeStoreFence();
#if ENABLE(COMPARE_AND_SWAP)
do {
if (m_ptr) {
delete newObject;
WTF::loadLoadFence();
return;
}
} while (!WTF::weakCompareAndSwap(bitwise_cast<void*volatile*>(&m_ptr), nullptr, newObject));
#else
m_ptr = newObject;
#endif
}
} // namespace WTF
using WTF::OwnPtr;
#endif // WTF_OwnPtr_h
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