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/*
* Copyright (C) 2005-2018 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.
*
*/
// RefPtr is documented at http://webkit.org/coding/RefPtr.html
#ifndef WTF_RefPtr_h
#define WTF_RefPtr_h
#include <algorithm>
#include <utility>
#include <wtf/FastMalloc.h>
#include <wtf/Ref.h>
namespace WTF {
template<typename T, typename PtrTraits> class RefPtr;
template<typename T, typename PtrTraits = DumbPtrTraits<T>> RefPtr<T, PtrTraits> adoptRef(T*);
template<typename T> ALWAYS_INLINE void refIfNotNull(T* ptr)
{
if (LIKELY(ptr != nullptr))
ptr->ref();
}
template<typename T> ALWAYS_INLINE void derefIfNotNull(T* ptr)
{
if (LIKELY(ptr != nullptr))
ptr->deref();
}
template<typename T, typename PtrTraits>
class RefPtr {
WTF_MAKE_FAST_ALLOCATED;
public:
typedef T ValueType;
typedef ValueType* PtrType;
static constexpr bool isRefPtr = true;
ALWAYS_INLINE constexpr RefPtr() : m_ptr(nullptr) { }
ALWAYS_INLINE RefPtr(T* ptr) : m_ptr(ptr) { refIfNotNull(ptr); }
ALWAYS_INLINE RefPtr(const RefPtr& o) : m_ptr(o.m_ptr) { refIfNotNull(PtrTraits::unwrap(m_ptr)); }
template<typename X, typename Y> RefPtr(const RefPtr<X, Y>& o) : m_ptr(o.get()) { refIfNotNull(PtrTraits::unwrap(m_ptr)); }
ALWAYS_INLINE RefPtr(RefPtr&& o) : m_ptr(o.leakRef()) { }
template<typename X, typename Y> RefPtr(RefPtr<X, Y>&& o) : m_ptr(o.leakRef()) { }
template<typename X, typename Y> RefPtr(Ref<X, Y>&&);
// Hash table deleted values, which are only constructed and never copied or destroyed.
RefPtr(HashTableDeletedValueType) : m_ptr(hashTableDeletedValue()) { }
bool isHashTableDeletedValue() const { return m_ptr == hashTableDeletedValue(); }
ALWAYS_INLINE ~RefPtr() { derefIfNotNull(PtrTraits::exchange(m_ptr, nullptr)); }
T* get() const { return PtrTraits::unwrap(m_ptr); }
Ref<T> releaseNonNull() { ASSERT(m_ptr); Ref<T> tmp(adoptRef(*m_ptr)); m_ptr = nullptr; return tmp; }
Ref<const T> releaseConstNonNull() { ASSERT(m_ptr); Ref<const T> tmp(adoptRef(*m_ptr)); m_ptr = nullptr; return tmp; }
T* leakRef() WARN_UNUSED_RETURN;
T& operator*() const { ASSERT(m_ptr); return *PtrTraits::unwrap(m_ptr); }
ALWAYS_INLINE T* operator->() const { return PtrTraits::unwrap(m_ptr); }
bool operator!() const { return !m_ptr; }
// This conversion operator allows implicit conversion to bool but not to other integer types.
typedef T* (RefPtr::*UnspecifiedBoolType);
operator UnspecifiedBoolType() const { return m_ptr ? &RefPtr::m_ptr : nullptr; }
explicit operator bool() const { return !!m_ptr; }
RefPtr& operator=(const RefPtr&);
RefPtr& operator=(T*);
RefPtr& operator=(std::nullptr_t);
template<typename X, typename Y> RefPtr& operator=(const RefPtr<X, Y>&);
RefPtr& operator=(RefPtr&&);
template<typename X, typename Y> RefPtr& operator=(RefPtr<X, Y>&&);
template<typename X> RefPtr& operator=(Ref<X>&&);
template<typename X, typename Y> void swap(RefPtr<X, Y>&);
static T* hashTableDeletedValue() { return reinterpret_cast<T*>(-1); }
RefPtr copyRef() && = delete;
RefPtr copyRef() const & WARN_UNUSED_RETURN { return RefPtr(m_ptr); }
private:
friend RefPtr adoptRef<T, PtrTraits>(T*);
template<typename X, typename Y> friend class RefPtr;
enum AdoptTag { Adopt };
RefPtr(T* ptr, AdoptTag) : m_ptr(ptr) { }
typename PtrTraits::StorageType m_ptr;
};
template<typename T, typename U>
template<typename X, typename Y>
inline RefPtr<T, U>::RefPtr(Ref<X, Y>&& reference)
: m_ptr(&reference.leakRef())
{
}
template<typename T, typename U>
inline T* RefPtr<T, U>::leakRef()
{
return U::exchange(m_ptr, nullptr);
}
template<typename T, typename U>
inline RefPtr<T, U>& RefPtr<T, U>::operator=(const RefPtr& o)
{
RefPtr ptr = o;
swap(ptr);
return *this;
}
template<typename T, typename U>
template<typename X, typename Y>
inline RefPtr<T, U>& RefPtr<T, U>::operator=(const RefPtr<X, Y>& o)
{
RefPtr ptr = o;
swap(ptr);
return *this;
}
template<typename T, typename U>
inline RefPtr<T, U>& RefPtr<T, U>::operator=(T* optr)
{
RefPtr ptr = optr;
swap(ptr);
return *this;
}
template<typename T, typename U>
inline RefPtr<T, U>& RefPtr<T, U>::operator=(std::nullptr_t)
{
derefIfNotNull(U::exchange(m_ptr, nullptr));
return *this;
}
template<typename T, typename U>
inline RefPtr<T, U>& RefPtr<T, U>::operator=(RefPtr&& o)
{
RefPtr ptr = WTFMove(o);
swap(ptr);
return *this;
}
template<typename T, typename U>
template<typename X, typename Y>
inline RefPtr<T, U>& RefPtr<T, U>::operator=(RefPtr<X, Y>&& o)
{
RefPtr ptr = WTFMove(o);
swap(ptr);
return *this;
}
template<typename T, typename V>
template<typename U>
inline RefPtr<T, V>& RefPtr<T, V>::operator=(Ref<U>&& reference)
{
RefPtr ptr = WTFMove(reference);
swap(ptr);
return *this;
}
template<class T, typename U>
template<typename X, typename Y>
inline void RefPtr<T, U>::swap(RefPtr<X, Y>& o)
{
U::swap(m_ptr, o.m_ptr);
}
template<typename T, typename U, typename X, typename Y, typename = std::enable_if_t<!std::is_same<U, DumbPtrTraits<T>>::value || !std::is_same<Y, DumbPtrTraits<X>>::value>>
inline void swap(RefPtr<T, U>& a, RefPtr<X, Y>& b)
{
a.swap(b);
}
template<typename T, typename U, typename X, typename Y>
inline bool operator==(const RefPtr<T, U>& a, const RefPtr<X, Y>& b)
{
return a.get() == b.get();
}
template<typename T, typename U, typename X>
inline bool operator==(const RefPtr<T, U>& a, X* b)
{
return a.get() == b;
}
template<typename T, typename X, typename Y>
inline bool operator==(T* a, const RefPtr<X, Y>& b)
{
return a == b.get();
}
template<typename T, typename U, typename X, typename Y>
inline bool operator!=(const RefPtr<T, U>& a, const RefPtr<X, Y>& b)
{
return a.get() != b.get();
}
template<typename T, typename U, typename X>
inline bool operator!=(const RefPtr<T, U>& a, X* b)
{
return a.get() != b;
}
template<typename T, typename X, typename Y>
inline bool operator!=(T* a, const RefPtr<X, Y>& b)
{
return a != b.get();
}
template<typename T, typename U = DumbPtrTraits<T>, typename X, typename Y>
inline RefPtr<T, U> static_pointer_cast(const RefPtr<X, Y>& p)
{
return RefPtr<T, U>(static_cast<T*>(p.get()));
}
template <typename T, typename U>
struct IsSmartPtr<RefPtr<T, U>> {
static const bool value = true;
};
template<typename T, typename U>
inline RefPtr<T, U> adoptRef(T* p)
{
adopted(p);
return RefPtr<T, U>(p, RefPtr<T, U>::Adopt);
}
template<typename T> inline RefPtr<T> makeRefPtr(T* pointer)
{
return pointer;
}
template<typename T> inline RefPtr<T> makeRefPtr(T& reference)
{
return &reference;
}
template<typename ExpectedType, typename ArgType, typename PtrTraits>
inline bool is(RefPtr<ArgType, PtrTraits>& source)
{
return is<ExpectedType>(source.get());
}
template<typename ExpectedType, typename ArgType, typename PtrTraits>
inline bool is(const RefPtr<ArgType, PtrTraits>& source)
{
return is<ExpectedType>(source.get());
}
template<typename Poison, typename T> struct PoisonedPtrTraits;
template<typename Poison, typename T>
using PoisonedRefPtr = RefPtr<T, PoisonedPtrTraits<Poison, T>>;
} // namespace WTF
using WTF::PoisonedRefPtr;
using WTF::RefPtr;
using WTF::adoptRef;
using WTF::makeRefPtr;
using WTF::static_pointer_cast;
#endif // WTF_RefPtr_h