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/*
* 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 <>
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
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