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/*
* Copyright (C) 2013-2020 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. AND ITS CONTRIBUTORS ``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 ITS 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/Assertions.h>
#include <wtf/Forward.h>
#include <wtf/GetPtr.h>
#include <wtf/RawPtrTraits.h>
#include <wtf/StdLibExtras.h>
#include <wtf/TypeCasts.h>
#if ASAN_ENABLED
extern "C" void __asan_poison_memory_region(void const volatile *addr, size_t size);
extern "C" void __asan_unpoison_memory_region(void const volatile *addr, size_t size);
extern "C" int __asan_address_is_poisoned(void const volatile *addr);
#endif
namespace WTF {
inline void adopted(const void*) { }
template<typename T, typename PtrTraits> class Ref;
template<typename T, typename PtrTraits = RawPtrTraits<T>> Ref<T, PtrTraits> adoptRef(T&);
template<typename T, typename Traits>
class Ref {
public:
using PtrTraits = Traits;
static constexpr bool isRef = true;
~Ref()
{
#if ASAN_ENABLED
if (__asan_address_is_poisoned(this))
__asan_unpoison_memory_region(this, sizeof(*this));
#endif
if (auto* ptr = PtrTraits::exchange(m_ptr, nullptr))
ptr->deref();
}
Ref(T& object)
: m_ptr(&object)
{
object.ref();
}
Ref(const Ref& other)
: m_ptr(other.ptr())
{
m_ptr->ref();
}
template<typename X, typename Y> Ref(const Ref<X, Y>& other)
: m_ptr(other.ptr())
{
m_ptr->ref();
}
Ref(Ref&& other)
: m_ptr(&other.leakRef())
{
ASSERT(m_ptr);
}
template<typename X, typename Y>
Ref(Ref<X, Y>&& other)
: m_ptr(&other.leakRef())
{
ASSERT(m_ptr);
}
Ref& operator=(T&);
Ref& operator=(Ref&&);
template<typename X, typename Y> Ref& operator=(Ref<X, Y>&&);
Ref& operator=(const Ref&);
template<typename X, typename Y> Ref& operator=(const Ref<X, Y>&);
template<typename X, typename Y> void swap(Ref<X, Y>&);
// Hash table deleted values, which are only constructed and never copied or destroyed.
Ref(HashTableDeletedValueType) : m_ptr(PtrTraits::hashTableDeletedValue()) { }
bool isHashTableDeletedValue() const { return PtrTraits::isHashTableDeletedValue(m_ptr); }
Ref(HashTableEmptyValueType) : m_ptr(hashTableEmptyValue()) { }
bool isHashTableEmptyValue() const { return m_ptr == hashTableEmptyValue(); }
static T* hashTableEmptyValue() { return nullptr; }
const T* ptrAllowingHashTableEmptyValue() const { ASSERT(m_ptr || isHashTableEmptyValue()); return PtrTraits::unwrap(m_ptr); }
T* ptrAllowingHashTableEmptyValue() { ASSERT(m_ptr || isHashTableEmptyValue()); return PtrTraits::unwrap(m_ptr); }
T* operator->() const { ASSERT(m_ptr); return PtrTraits::unwrap(m_ptr); }
T* ptr() const RETURNS_NONNULL { ASSERT(m_ptr); return PtrTraits::unwrap(m_ptr); }
T& get() const { ASSERT(m_ptr); return *PtrTraits::unwrap(m_ptr); }
operator T&() const { ASSERT(m_ptr); return *PtrTraits::unwrap(m_ptr); }
bool operator!() const { ASSERT(m_ptr); return !*m_ptr; }
template<typename X, typename Y> Ref<T, PtrTraits> replace(Ref<X, Y>&&) WARN_UNUSED_RETURN;
// The following function is deprecated.
Ref copyRef() && = delete;
Ref copyRef() const & WARN_UNUSED_RETURN { return Ref(*m_ptr); }
T& leakRef() WARN_UNUSED_RETURN
{
ASSERT(m_ptr);
T& result = *PtrTraits::exchange(m_ptr, nullptr);
#if ASAN_ENABLED
__asan_poison_memory_region(this, sizeof(*this));
#endif
return result;
}
private:
friend Ref adoptRef<T>(T&);
template<typename X, typename Y> friend class Ref;
enum AdoptTag { Adopt };
Ref(T& object, AdoptTag)
: m_ptr(&object)
{
}
typename PtrTraits::StorageType m_ptr;
};
template<typename T, typename U> Ref<T, U> adoptRef(T&);
template<typename T, typename U>
inline Ref<T, U>& Ref<T, U>::operator=(T& reference)
{
Ref copiedReference = reference;
swap(copiedReference);
return *this;
}
template<typename T, typename U>
inline Ref<T, U>& Ref<T, U>::operator=(Ref&& reference)
{
#if ASAN_ENABLED
if (__asan_address_is_poisoned(this))
__asan_unpoison_memory_region(this, sizeof(*this));
#endif
Ref movedReference = WTFMove(reference);
swap(movedReference);
return *this;
}
template<typename T, typename U>
template<typename X, typename Y>
inline Ref<T, U>& Ref<T, U>::operator=(Ref<X, Y>&& reference)
{
#if ASAN_ENABLED
if (__asan_address_is_poisoned(this))
__asan_unpoison_memory_region(this, sizeof(*this));
#endif
Ref movedReference = WTFMove(reference);
swap(movedReference);
return *this;
}
template<typename T, typename U>
inline Ref<T, U>& Ref<T, U>::operator=(const Ref& reference)
{
#if ASAN_ENABLED
if (__asan_address_is_poisoned(this))
__asan_unpoison_memory_region(this, sizeof(*this));
#endif
Ref copiedReference = reference;
swap(copiedReference);
return *this;
}
template<typename T, typename U>
template<typename X, typename Y>
inline Ref<T, U>& Ref<T, U>::operator=(const Ref<X, Y>& reference)
{
#if ASAN_ENABLED
if (__asan_address_is_poisoned(this))
__asan_unpoison_memory_region(this, sizeof(*this));
#endif
Ref copiedReference = reference;
swap(copiedReference);
return *this;
}
template<typename T, typename U>
template<typename X, typename Y>
inline void Ref<T, U>::swap(Ref<X, Y>& other)
{
U::swap(m_ptr, other.m_ptr);
}
template<typename T, typename U, typename X, typename Y, typename = std::enable_if_t<!std::is_same<U, RawPtrTraits<T>>::value || !std::is_same<Y, RawPtrTraits<X>>::value>>
inline void swap(Ref<T, U>& a, Ref<X, Y>& b)
{
a.swap(b);
}
template<typename T, typename U>
template<typename X, typename Y>
inline Ref<T, U> Ref<T, U>::replace(Ref<X, Y>&& reference)
{
#if ASAN_ENABLED
if (__asan_address_is_poisoned(this))
__asan_unpoison_memory_region(this, sizeof(*this));
#endif
auto oldReference = adoptRef(*m_ptr);
m_ptr = &reference.leakRef();
return oldReference;
}
template<typename T, typename U = RawPtrTraits<T>, typename X, typename Y>
inline Ref<T, U> static_reference_cast(Ref<X, Y>&& reference)
{
return adoptRef(static_cast<T&>(reference.leakRef()));
}
template<typename T, typename U = RawPtrTraits<T>, typename X, typename Y>
ALWAYS_INLINE Ref<T, U> static_reference_cast(const Ref<X, Y>& reference)
{
return static_reference_cast<T, U>(reference.copyRef());
}
template <typename T, typename U>
struct GetPtrHelper<Ref<T, U>> {
typedef T* PtrType;
static T* getPtr(const Ref<T, U>& p) { return const_cast<T*>(p.ptr()); }
};
template <typename T, typename U>
struct IsSmartPtr<Ref<T, U>> {
static constexpr bool value = true;
};
template<typename T, typename U>
inline Ref<T, U> adoptRef(T& reference)
{
adopted(&reference);
return Ref<T, U>(reference, Ref<T, U>::Adopt);
}
template<typename ExpectedType, typename ArgType, typename PtrTraits>
inline bool is(Ref<ArgType, PtrTraits>& source)
{
return is<ExpectedType>(source.get());
}
template<typename ExpectedType, typename ArgType, typename PtrTraits>
inline bool is(const Ref<ArgType, PtrTraits>& source)
{
return is<ExpectedType>(source.get());
}
} // namespace WTF
using WTF::Ref;
using WTF::adoptRef;
using WTF::static_reference_cast;