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/*
* Copyright (C) 2009, 2010 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.
*/
#ifndef WTF_PassOwnPtr_h
#define WTF_PassOwnPtr_h
#include <wtf/Assertions.h>
#include <wtf/NullPtr.h>
#include <wtf/OwnPtrCommon.h>
#include <wtf/TypeTraits.h>
namespace WTF {
// Unlike most of our smart pointers, PassOwnPtr can take either the pointer type or the pointed-to type.
template<typename T> class OwnPtr;
template<typename T> class PassOwnPtr;
template<typename T> PassOwnPtr<T> adoptPtr(T*);
class RefCountedBase;
class ThreadSafeRefCountedBase;
template<typename T> class PassOwnPtr {
public:
typedef typename RemovePointer<T>::Type ValueType;
typedef ValueType* PtrType;
PassOwnPtr() : m_ptr(0) { }
PassOwnPtr(std::nullptr_t) : m_ptr(0) { }
// It somewhat breaks the type system to allow transfer of ownership out of
// a const PassOwnPtr. However, it makes it much easier to work with PassOwnPtr
// temporaries, and we don't have a need to use real const PassOwnPtrs anyway.
PassOwnPtr(const PassOwnPtr& o) : m_ptr(o.leakPtr()) { }
template<typename U> PassOwnPtr(const PassOwnPtr<U>& o) : m_ptr(o.leakPtr()) { }
~PassOwnPtr() { deleteOwnedPtr(m_ptr); }
PtrType get() const { return m_ptr; }
PtrType leakPtr() const 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 PassOwnPtr::*UnspecifiedBoolType;
operator UnspecifiedBoolType() const { return m_ptr ? &PassOwnPtr::m_ptr : 0; }
PassOwnPtr& operator=(const PassOwnPtr&) { COMPILE_ASSERT(!sizeof(T*), PassOwnPtr_should_never_be_assigned_to); return *this; }
template<typename U> friend PassOwnPtr<U> adoptPtr(U*);
private:
explicit PassOwnPtr(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 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; }
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; }
mutable PtrType m_ptr;
};
template<typename T> inline typename PassOwnPtr<T>::PtrType PassOwnPtr<T>::leakPtr() const
{
PtrType ptr = m_ptr;
m_ptr = 0;
return ptr;
}
template<typename T, typename U> inline bool operator==(const PassOwnPtr<T>& a, const PassOwnPtr<U>& b)
{
return a.get() == b.get();
}
template<typename T, typename U> inline bool operator==(const PassOwnPtr<T>& a, const OwnPtr<U>& b)
{
return a.get() == b.get();
}
template<typename T, typename U> inline bool operator==(const OwnPtr<T>& a, const PassOwnPtr<U>& b)
{
return a.get() == b.get();
}
template<typename T, typename U> inline bool operator==(const PassOwnPtr<T>& a, U* b)
{
return a.get() == b;
}
template<typename T, typename U> inline bool operator==(T* a, const PassOwnPtr<U>& b)
{
return a == b.get();
}
template<typename T, typename U> inline bool operator!=(const PassOwnPtr<T>& a, const PassOwnPtr<U>& b)
{
return a.get() != b.get();
}
template<typename T, typename U> inline bool operator!=(const PassOwnPtr<T>& a, const OwnPtr<U>& b)
{
return a.get() != b.get();
}
template<typename T, typename U> inline bool operator!=(const OwnPtr<T>& a, const PassOwnPtr<U>& b)
{
return a.get() != b.get();
}
template<typename T, typename U> inline bool operator!=(const PassOwnPtr<T>& a, U* b)
{
return a.get() != b;
}
template<typename T, typename U> inline bool operator!=(T* a, const PassOwnPtr<U>& b)
{
return a != b.get();
}
template<typename T> inline PassOwnPtr<T> adoptPtr(T* ptr)
{
COMPILE_ASSERT(!(IsSubclass<T, RefCountedBase>::value), DoNotUseAdoptPtrWithRefCounted);
COMPILE_ASSERT(!(IsSubclass<T, ThreadSafeRefCountedBase>::value), DoNotUseAdoptPtrWithThreadSafeRefCounted);
return PassOwnPtr<T>(ptr);
}
template<typename T, typename U> inline PassOwnPtr<T> static_pointer_cast(const PassOwnPtr<U>& p)
{
return adoptPtr(static_cast<T*>(p.leakPtr()));
}
template<typename T, typename U> inline PassOwnPtr<T> const_pointer_cast(const PassOwnPtr<U>& p)
{
return adoptPtr(const_cast<T*>(p.leakPtr()));
}
template<typename T> inline T* getPtr(const PassOwnPtr<T>& p)
{
return p.get();
}
} // namespace WTF
using WTF::PassOwnPtr;
using WTF::adoptPtr;
using WTF::const_pointer_cast;
using WTF::static_pointer_cast;
#endif // WTF_PassOwnPtr_h
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