| /* |
| * Copyright (C) 2009, 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 CrossThreadCopier_h |
| #define CrossThreadCopier_h |
| |
| #include "platform/PlatformExport.h" |
| #include "platform/heap/Handle.h" |
| #include "wtf/Assertions.h" |
| #include "wtf/Forward.h" |
| #include "wtf/PassOwnPtr.h" |
| #include "wtf/PassRefPtr.h" |
| #include "wtf/RawPtr.h" |
| #include "wtf/RefPtr.h" |
| #include "wtf/ThreadSafeRefCounted.h" |
| #include "wtf/TypeTraits.h" |
| |
| namespace blink { |
| |
| class IntRect; |
| class IntSize; |
| class KURL; |
| class ResourceError; |
| class ResourceRequest; |
| class ResourceResponse; |
| struct CrossThreadResourceResponseData; |
| struct CrossThreadResourceRequestData; |
| |
| template <typename T> |
| struct CrossThreadCopierPassThrough { |
| STATIC_ONLY(CrossThreadCopierPassThrough); |
| typedef T Type; |
| static Type copy(const T& parameter) |
| { |
| return parameter; |
| } |
| }; |
| |
| template <typename T, bool isArithmeticOrEnum, bool isThreadSafeRefCounted, bool isGarbageCollected> |
| struct CrossThreadCopierBase; |
| |
| // Arithmetic values (integers or floats) and enums can be safely copied. |
| template <typename T, bool isThreadSafeRefCounted, bool isGarbageCollected> |
| struct CrossThreadCopierBase<T, true, isThreadSafeRefCounted, isGarbageCollected> : public CrossThreadCopierPassThrough<T> { |
| STATIC_ONLY(CrossThreadCopierBase); |
| }; |
| |
| // Custom copy method for ThreadSafeRefCounted. |
| template <typename T, bool isGarbageCollected> |
| struct CrossThreadCopierBase<T, false, true, isGarbageCollected> { |
| STATIC_ONLY(CrossThreadCopierBase); |
| typedef typename WTF::RemoveTemplate<T, RefPtr>::Type TypeWithoutRefPtr; |
| typedef typename WTF::RemoveTemplate<TypeWithoutRefPtr, PassRefPtr>::Type TypeWithoutPassRefPtr; |
| typedef typename std::remove_pointer<TypeWithoutPassRefPtr>::type RefCountedType; |
| |
| // Verify that only one of the above did a change. |
| static_assert((std::is_same<RefPtr<RefCountedType>, T>::value |
| || std::is_same<PassRefPtr<RefCountedType>, T>::value |
| || std::is_same<RefCountedType*, T>::value), |
| "only one type modification should be allowed"); |
| |
| typedef PassRefPtr<RefCountedType> Type; |
| static Type copy(const T& refPtr) |
| { |
| return refPtr; |
| } |
| }; |
| |
| // A pointer to GarbageCollected. |
| template <typename T> |
| struct CrossThreadCopierBase<T, false, false, true> { |
| STATIC_ONLY(CrossThreadCopierBase); |
| typedef typename std::remove_pointer<T>::type TypeWithoutPointer; |
| typedef RawPtr<TypeWithoutPointer> Type; |
| static Type copy(const T& ptr) |
| { |
| return ptr; |
| } |
| }; |
| |
| template <typename T> |
| struct CrossThreadCopier : public CrossThreadCopierBase< |
| T, |
| std::is_arithmetic<T>::value || std::is_enum<T>::value, |
| WTF::IsSubclassOfTemplate<typename WTF::RemoveTemplate<T, RefPtr>::Type, ThreadSafeRefCounted>::value |
| || WTF::IsSubclassOfTemplate<typename std::remove_pointer<T>::type, ThreadSafeRefCounted>::value |
| || WTF::IsSubclassOfTemplate<typename WTF::RemoveTemplate<T, PassRefPtr>::Type, ThreadSafeRefCounted>::value, |
| WTF::IsSubclassOfTemplate<typename std::remove_pointer<T>::type, GarbageCollected>::value> { |
| STATIC_ONLY(CrossThreadCopier); |
| }; |
| |
| // CrossThreadCopier specializations follow. |
| |
| // nullptr_t can be passed through without any changes. |
| template <> |
| struct CrossThreadCopier<std::nullptr_t> : public CrossThreadCopierPassThrough<std::nullptr_t> { |
| STATIC_ONLY(CrossThreadCopier); |
| }; |
| |
| // To allow a type to be passed across threads using its copy constructor, add a forward declaration of the type and |
| // provide a specialization of CrossThreadCopier<T> in this file, like IntRect below. |
| template <> |
| struct CrossThreadCopier<IntRect> : public CrossThreadCopierPassThrough<IntRect> { |
| STATIC_ONLY(CrossThreadCopier); |
| }; |
| |
| template <> |
| struct CrossThreadCopier<IntSize> : public CrossThreadCopierPassThrough<IntSize> { |
| STATIC_ONLY(CrossThreadCopier); |
| }; |
| |
| template <typename T> |
| struct CrossThreadCopier<PassOwnPtr<T>> { |
| STATIC_ONLY(CrossThreadCopier); |
| typedef PassOwnPtr<T> Type; |
| static Type copy(Type ownPtr) |
| { |
| return ownPtr; |
| } |
| }; |
| |
| template <typename T> |
| struct CrossThreadCopier<WeakMember<T>*> { |
| STATIC_ONLY(CrossThreadCopier); |
| typedef WeakMember<T>* Type; |
| static Type copy(Type ptr) |
| { |
| return ptr; |
| } |
| }; |
| |
| template<typename T> |
| struct CrossThreadCopier<CrossThreadWeakPersistentThisPointer<T>> : public CrossThreadCopierPassThrough<CrossThreadWeakPersistentThisPointer<T>> { |
| STATIC_ONLY(CrossThreadCopier); |
| }; |
| |
| template <> |
| struct CrossThreadCopier<KURL> { |
| STATIC_ONLY(CrossThreadCopier); |
| typedef KURL Type; |
| PLATFORM_EXPORT static Type copy(const KURL&); |
| }; |
| |
| template <> |
| struct CrossThreadCopier<String> { |
| STATIC_ONLY(CrossThreadCopier); |
| typedef String Type; |
| PLATFORM_EXPORT static Type copy(const String&); |
| }; |
| |
| template <> |
| struct CrossThreadCopier<ResourceError> { |
| STATIC_ONLY(CrossThreadCopier); |
| typedef ResourceError Type; |
| PLATFORM_EXPORT static Type copy(const ResourceError&); |
| }; |
| |
| template <> |
| struct CrossThreadCopier<ResourceRequest> { |
| STATIC_ONLY(CrossThreadCopier); |
| typedef PassOwnPtr<CrossThreadResourceRequestData> Type; |
| PLATFORM_EXPORT static Type copy(const ResourceRequest&); |
| }; |
| |
| template <> |
| struct CrossThreadCopier<ResourceResponse> { |
| STATIC_ONLY(CrossThreadCopier); |
| typedef PassOwnPtr<CrossThreadResourceResponseData> Type; |
| PLATFORM_EXPORT static Type copy(const ResourceResponse&); |
| }; |
| |
| template <typename T> |
| struct CrossThreadCopier<RawPtr<T>> { |
| STATIC_ONLY(CrossThreadCopier); |
| static_assert(IsGarbageCollectedType<T>::value, "T must be a garbage-collected type."); |
| typedef RawPtr<T> Type; |
| static Type copy(const Type& ptr) |
| { |
| return ptr; |
| } |
| }; |
| |
| template <typename T> |
| struct CrossThreadCopier<Member<T>> { |
| STATIC_ONLY(CrossThreadCopier); |
| static_assert(IsGarbageCollectedType<T>::value, "T must be a garbage-collected type."); |
| typedef RawPtr<T> Type; |
| static Type copy(const Member<T>& ptr) |
| { |
| return ptr; |
| } |
| }; |
| |
| template <typename T> |
| struct CrossThreadCopier<WeakMember<T>> { |
| STATIC_ONLY(CrossThreadCopier); |
| static_assert(IsGarbageCollectedType<T>::value, "T must be a garbage-collected type."); |
| typedef RawPtr<T> Type; |
| static Type copy(const WeakMember<T>& ptr) |
| { |
| return ptr; |
| } |
| }; |
| |
| // |T| is |C*| or |const WeakPtr<C>&|. |
| template <typename T> |
| struct AllowCrossThreadAccessWrapper { |
| STACK_ALLOCATED(); |
| public: |
| explicit AllowCrossThreadAccessWrapper(T value) : m_value(value) { } |
| T value() const { return m_value; } |
| private: |
| // This raw pointer is safe since AllowCrossThreadAccessWrapper is |
| // always stack-allocated. Ideally this should be Member<T> if T is |
| // garbage-collected and T* otherwise, but we don't want to introduce |
| // another template magic just for distinguishing Member<T> from T*. |
| // From the perspective of GC, T* always works correctly. |
| GC_PLUGIN_IGNORE("") |
| T m_value; |
| }; |
| |
| template <typename T> |
| struct CrossThreadCopier<AllowCrossThreadAccessWrapper<T>> { |
| STATIC_ONLY(CrossThreadCopier); |
| typedef T Type; |
| static Type copy(const AllowCrossThreadAccessWrapper<T>& wrapper) { return wrapper.value(); } |
| }; |
| |
| template <typename T> |
| AllowCrossThreadAccessWrapper<T*> AllowCrossThreadAccess(T* value) |
| { |
| return AllowCrossThreadAccessWrapper<T*>(value); |
| } |
| |
| template <typename T> |
| AllowCrossThreadAccessWrapper<const WeakPtr<T>&> AllowCrossThreadAccess(const WeakPtr<T>& value) |
| { |
| return AllowCrossThreadAccessWrapper<const WeakPtr<T>&>(value); |
| } |
| |
| } // namespace blink |
| |
| #endif // CrossThreadCopier_h |