| /* |
| * Copyright (C) 2010 Google 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: |
| * |
| * * Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * * 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. |
| * * Neither the name of Google Inc. nor the names of its |
| * contributors may be used to endorse or promote products derived from |
| * this software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND 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 THE COPYRIGHT |
| * OWNER 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 WebPrivatePtr_h |
| #define WebPrivatePtr_h |
| |
| #include "WebCommon.h" |
| |
| #if INSIDE_BLINK |
| #include "platform/heap/Handle.h" |
| #include "wtf/PassRefPtr.h" |
| #include "wtf/TypeTraits.h" |
| #endif |
| |
| namespace WTF { |
| template<class T> class ThreadSafeRefCounted; |
| } |
| |
| namespace blink { |
| |
| // By default, the destruction of a WebPrivatePtr<> must happen on the same |
| // thread that created it, but can optionally be allowed to happen on |
| // another thread. |
| enum WebPrivatePtrDestruction { |
| WebPrivatePtrDestructionSameThread, |
| WebPrivatePtrDestructionCrossThread, |
| }; |
| |
| #if INSIDE_BLINK |
| enum LifetimeManagementType { |
| RefCountedLifetime, |
| GarbageCollectedLifetime, |
| RefCountedGarbageCollectedLifetime |
| }; |
| |
| template<typename T> |
| class LifetimeOf { |
| static const bool isGarbageCollected = WTF::IsSubclassOfTemplate<T, GarbageCollected>::value || IsGarbageCollectedMixin<T>::value; |
| static const bool isRefCountedGarbageCollected = WTF::IsSubclassOfTemplate<T, RefCountedGarbageCollected>::value; |
| public: |
| static const LifetimeManagementType value = |
| !isGarbageCollected ? RefCountedLifetime : |
| isRefCountedGarbageCollected ? RefCountedGarbageCollectedLifetime : GarbageCollectedLifetime; |
| }; |
| |
| template<typename T, WebPrivatePtrDestruction crossThreadDestruction, LifetimeManagementType lifetime> |
| class PtrStorageImpl; |
| |
| template<typename T, WebPrivatePtrDestruction crossThreadDestruction> |
| class PtrStorageImpl<T, crossThreadDestruction, RefCountedLifetime> { |
| public: |
| typedef PassRefPtr<T> BlinkPtrType; |
| |
| void assign(const BlinkPtrType& val) |
| { |
| static_assert(crossThreadDestruction == WebPrivatePtrDestructionSameThread || WTF::IsSubclassOfTemplate<T, WTF::ThreadSafeRefCounted>::value, "Cross thread destructible class must derive from ThreadSafeRefCounted<>"); |
| release(); |
| m_ptr = val.leakRef(); |
| } |
| |
| void assign(const PtrStorageImpl& other) |
| { |
| release(); |
| T* val = other.get(); |
| WTF::refIfNotNull(val); |
| m_ptr = val; |
| } |
| |
| void moveFrom(PtrStorageImpl& other) |
| { |
| release(); |
| m_ptr = other.m_ptr; |
| other.m_ptr = 0; |
| } |
| |
| T* get() const { return m_ptr; } |
| |
| void release() |
| { |
| WTF::derefIfNotNull(m_ptr); |
| m_ptr = 0; |
| } |
| |
| private: |
| T* m_ptr; |
| }; |
| |
| template <typename T, WebPrivatePtrDestruction> |
| struct WebPrivatePtrPersistentStorageType { |
| public: |
| using Type = Persistent<T>; |
| }; |
| |
| template <typename T> |
| struct WebPrivatePtrPersistentStorageType<T, WebPrivatePtrDestructionCrossThread> { |
| public: |
| using Type = CrossThreadPersistent<T>; |
| }; |
| |
| template<typename T, WebPrivatePtrDestruction crossThreadDestruction> |
| class PtrStorageImpl<T, crossThreadDestruction, GarbageCollectedLifetime> { |
| public: |
| void assign(const RawPtr<T>& val) |
| { |
| if (!val) { |
| release(); |
| return; |
| } |
| |
| if (!m_handle) |
| m_handle = new (typename WebPrivatePtrPersistentStorageType<T, crossThreadDestruction>::Type)(); |
| |
| (*m_handle) = val; |
| } |
| |
| void assign(T* ptr) { assign(RawPtr<T>(ptr)); } |
| template<typename U> void assign(const RawPtr<U>& val) { assign(RawPtr<T>(val)); } |
| |
| void assign(const PtrStorageImpl& other) { assign(other.get()); } |
| |
| void moveFrom(PtrStorageImpl& other) |
| { |
| release(); |
| m_handle = other.m_handle; |
| other.m_handle = 0; |
| } |
| |
| T* get() const { return m_handle ? m_handle->get() : 0; } |
| |
| void release() |
| { |
| delete m_handle; |
| m_handle = 0; |
| } |
| |
| private: |
| typename WebPrivatePtrPersistentStorageType<T, crossThreadDestruction>::Type* m_handle; |
| }; |
| |
| template<typename T, WebPrivatePtrDestruction crossThreadDestruction> |
| class PtrStorageImpl<T, crossThreadDestruction, RefCountedGarbageCollectedLifetime> : public PtrStorageImpl<T, crossThreadDestruction, GarbageCollectedLifetime> { |
| public: |
| void assign(const PassRefPtrWillBeRawPtr<T>& val) { PtrStorageImpl<T, crossThreadDestruction, GarbageCollectedLifetime>::assign(val.get()); } |
| |
| void assign(const PtrStorageImpl& other) { PtrStorageImpl<T, crossThreadDestruction, GarbageCollectedLifetime>::assign(other.get()); } |
| }; |
| |
| template<typename T, WebPrivatePtrDestruction crossThreadDestruction> |
| class PtrStorage : public PtrStorageImpl<T, crossThreadDestruction, LifetimeOf<T>::value> { |
| public: |
| static PtrStorage& fromSlot(void** slot) |
| { |
| static_assert(sizeof(PtrStorage) == sizeof(void*), "PtrStorage must be the size of a pointer"); |
| return *reinterpret_cast<PtrStorage*>(slot); |
| } |
| |
| static const PtrStorage& fromSlot(void* const* slot) |
| { |
| static_assert(sizeof(PtrStorage) == sizeof(void*), "PtrStorage must be the size of a pointer"); |
| return *reinterpret_cast<const PtrStorage*>(slot); |
| } |
| |
| private: |
| // Prevent construction via normal means. |
| PtrStorage(); |
| PtrStorage(const PtrStorage&); |
| }; |
| #endif |
| |
| // This class is an implementation detail of the Blink API. It exists to help |
| // simplify the implementation of Blink interfaces that merely wrap a reference |
| // counted WebCore class. |
| // |
| // A typical implementation of a class which uses WebPrivatePtr might look like |
| // this: |
| // class WebFoo { |
| // public: |
| // BLINK_EXPORT ~WebFoo(); |
| // WebFoo() { } |
| // WebFoo(const WebFoo& other) { assign(other); } |
| // WebFoo& operator=(const WebFoo& other) |
| // { |
| // assign(other); |
| // return *this; |
| // } |
| // BLINK_EXPORT void assign(const WebFoo&); // Implemented in the body. |
| // |
| // // Methods that are exposed to Chromium and which are specific to |
| // // WebFoo go here. |
| // BLINK_EXPORT doWebFooThing(); |
| // |
| // // Methods that are used only by other Blink classes should only be |
| // // declared when INSIDE_BLINK is set. |
| // #if INSIDE_BLINK |
| // WebFoo(const WTF::PassRefPtr<Foo>&); |
| // #endif |
| // |
| // private: |
| // WebPrivatePtr<Foo> m_private; |
| // }; |
| // |
| // // WebFoo.cpp |
| // WebFoo::~WebFoo() { m_private.reset(); } |
| // void WebFoo::assign(const WebFoo& other) { ... } |
| // |
| template <typename T, WebPrivatePtrDestruction crossThreadDestruction = WebPrivatePtrDestructionSameThread> |
| class WebPrivatePtr { |
| public: |
| WebPrivatePtr() : m_storage(0) { } |
| ~WebPrivatePtr() |
| { |
| // We don't destruct the object pointed by m_ptr here because we don't |
| // want to expose destructors of core classes to embedders. We should |
| // call reset() manually in destructors of classes with WebPrivatePtr |
| // members. |
| BLINK_ASSERT(!m_storage); |
| } |
| |
| bool isNull() const { return !m_storage; } |
| |
| #if INSIDE_BLINK |
| template<typename U> |
| WebPrivatePtr(const U& ptr) |
| : m_storage(0) |
| { |
| storage().assign(ptr); |
| } |
| |
| void reset() { storage().release(); } |
| |
| WebPrivatePtr& operator=(const WebPrivatePtr& other) |
| { |
| storage().assign(other.storage()); |
| return *this; |
| } |
| |
| void moveFrom(WebPrivatePtr& other) |
| { |
| storage().moveFrom(other.storage()); |
| return; |
| } |
| |
| template<typename U> |
| WebPrivatePtr& operator=(const U& ptr) |
| { |
| storage().assign(ptr); |
| return *this; |
| } |
| |
| T* get() const { return storage().get(); } |
| |
| T& operator*() const |
| { |
| ASSERT(m_storage); |
| return *get(); |
| } |
| |
| T* operator->() const |
| { |
| ASSERT(m_storage); |
| return get(); |
| } |
| #endif |
| |
| private: |
| #if INSIDE_BLINK |
| PtrStorage<T, crossThreadDestruction>& storage() { return PtrStorage<T, crossThreadDestruction>::fromSlot(&m_storage); } |
| const PtrStorage<T, crossThreadDestruction>& storage() const { return PtrStorage<T, crossThreadDestruction>::fromSlot(&m_storage); } |
| #endif |
| |
| #if !INSIDE_BLINK |
| // Disable the assignment operator; we define it above for when |
| // INSIDE_BLINK is set, but we need to make sure that it is not |
| // used outside there; the compiler-provided version won't handle reference |
| // counting properly. |
| WebPrivatePtr& operator=(const WebPrivatePtr& other); |
| #endif |
| // Disable the copy constructor; classes that contain a WebPrivatePtr |
| // should implement their copy constructor using assign(). |
| WebPrivatePtr(const WebPrivatePtr&); |
| |
| void* m_storage; |
| }; |
| |
| } // namespace blink |
| |
| #endif |