| /** |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| */ |
| #ifndef WTF_Ref_h |
| #define WTF_Ref_h |
| |
| #include <wtf/Assertions.h> |
| #include <wtf/GetPtr.h> |
| #include <wtf/Noncopyable.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> class Ref; |
| template<typename T> Ref<T> adoptRef(T&); |
| |
| template<typename T> class Ref { |
| public: |
| static constexpr bool isRef = true; |
| |
| ~Ref() |
| { |
| #if ASAN_ENABLED |
| if (__asan_address_is_poisoned(this)) |
| __asan_unpoison_memory_region(this, sizeof(*this)); |
| #endif |
| if (m_ptr) |
| m_ptr->deref(); |
| } |
| |
| Ref(T& object) |
| : m_ptr(&object) |
| { |
| m_ptr->ref(); |
| } |
| |
| // Use copyRef() instead. |
| Ref(const Ref& other) = delete; |
| template<typename U> Ref(const Ref<U>& other) = delete; |
| |
| Ref(Ref&& other) |
| : m_ptr(&other.leakRef()) |
| { |
| ASSERT(m_ptr); |
| } |
| |
| template<typename U> |
| Ref(Ref<U>&& other) |
| : m_ptr(&other.leakRef()) |
| { |
| ASSERT(m_ptr); |
| } |
| |
| Ref& operator=(T& object) |
| { |
| ASSERT(m_ptr); |
| object.ref(); |
| m_ptr->deref(); |
| m_ptr = &object; |
| ASSERT(m_ptr); |
| return *this; |
| } |
| |
| // Use copyRef() and the move assignment operators instead. |
| Ref& operator=(const Ref& reference) = delete; |
| template<typename U> Ref& operator=(const Ref<U>& reference) = delete; |
| |
| Ref& operator=(Ref&& reference) |
| { |
| ASSERT(m_ptr); |
| m_ptr->deref(); |
| m_ptr = &reference.leakRef(); |
| ASSERT(m_ptr); |
| return *this; |
| } |
| |
| template<typename U> Ref& operator=(Ref<U>&& reference) |
| { |
| ASSERT(m_ptr); |
| m_ptr->deref(); |
| m_ptr = &reference.leakRef(); |
| ASSERT(m_ptr); |
| return *this; |
| } |
| |
| // Hash table deleted values, which are only constructed and never copied or destroyed. |
| Ref(HashTableDeletedValueType) : m_ptr(hashTableDeletedValue()) { } |
| bool isHashTableDeletedValue() const { return m_ptr == hashTableDeletedValue(); } |
| static T* hashTableDeletedValue() { return reinterpret_cast<T*>(-1); } |
| |
| 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 m_ptr; } |
| T* ptrAllowingHashTableEmptyValue() { ASSERT(m_ptr || isHashTableEmptyValue()); return m_ptr; } |
| |
| void assignToHashTableEmptyValue(Ref&& reference) |
| { |
| ASSERT(m_ptr == hashTableEmptyValue()); |
| m_ptr = &reference.leakRef(); |
| ASSERT(m_ptr); |
| } |
| |
| T* operator->() const { ASSERT(m_ptr); return m_ptr; } |
| T* ptr() const { ASSERT(m_ptr); return m_ptr; } |
| T& get() const { ASSERT(m_ptr); return *m_ptr; } |
| operator T&() const { ASSERT(m_ptr); return *m_ptr; } |
| bool operator!() const { ASSERT(m_ptr); return !*m_ptr; } |
| |
| template<typename U> Ref<T> replace(Ref<U>&&) WARN_UNUSED_RETURN; |
| |
| #if COMPILER_SUPPORTS(CXX_REFERENCE_QUALIFIED_FUNCTIONS) |
| Ref copyRef() && = delete; |
| Ref copyRef() const & WARN_UNUSED_RETURN { return Ref(*m_ptr); } |
| #else |
| Ref copyRef() const WARN_UNUSED_RETURN { return Ref(*m_ptr); } |
| #endif |
| |
| T& leakRef() WARN_UNUSED_RETURN |
| { |
| ASSERT(m_ptr); |
| |
| T& result = *std::exchange(m_ptr, nullptr); |
| #if ASAN_ENABLED |
| __asan_poison_memory_region(this, sizeof(*this)); |
| #endif |
| return result; |
| } |
| |
| private: |
| friend Ref adoptRef<T>(T&); |
| |
| enum AdoptTag { Adopt }; |
| Ref(T& object, AdoptTag) |
| : m_ptr(&object) |
| { |
| } |
| |
| T* m_ptr; |
| }; |
| |
| template<typename T> template<typename U> inline Ref<T> Ref<T>::replace(Ref<U>&& reference) |
| { |
| auto oldReference = adoptRef(*m_ptr); |
| m_ptr = &reference.leakRef(); |
| return oldReference; |
| } |
| |
| template<typename T, typename U> inline Ref<T> static_reference_cast(Ref<U>& reference) |
| { |
| return Ref<T>(static_cast<T&>(reference.get())); |
| } |
| |
| template<typename T, typename U> inline Ref<T> static_reference_cast(Ref<U>&& reference) |
| { |
| return adoptRef(static_cast<T&>(reference.leakRef())); |
| } |
| |
| template<typename T, typename U> inline Ref<T> static_reference_cast(const Ref<U>& reference) |
| { |
| return Ref<T>(static_cast<T&>(reference.copyRef().get())); |
| } |
| |
| template <typename T> |
| struct GetPtrHelper<Ref<T>> { |
| typedef T* PtrType; |
| static T* getPtr(const Ref<T>& p) { return const_cast<T*>(p.ptr()); } |
| }; |
| |
| template <typename T> |
| struct IsSmartPtr<Ref<T>> { |
| static const bool value = true; |
| }; |
| |
| template<typename T> |
| inline Ref<T> adoptRef(T& reference) |
| { |
| adopted(&reference); |
| return Ref<T>(reference, Ref<T>::Adopt); |
| } |
| |
| template<typename T> |
| inline Ref<T> makeRef(T& reference) |
| { |
| return Ref<T>(reference); |
| } |
| |
| template<typename ExpectedType, typename ArgType> inline bool is(Ref<ArgType>& source) |
| { |
| return is<ExpectedType>(source.get()); |
| } |
| |
| template<typename ExpectedType, typename ArgType> inline bool is(const Ref<ArgType>& source) |
| { |
| return is<ExpectedType>(source.get()); |
| } |
| |
| } // namespace WTF |
| |
| using WTF::Ref; |
| using WTF::adoptRef; |
| using WTF::makeRef; |
| using WTF::static_reference_cast; |
| |
| #endif // WTF_Ref_h |