1 /* 2 * Copyright (C) 2009, 2010 Google Inc. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions are 6 * met: 7 * 8 * * Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * * Redistributions in binary form must reproduce the above 11 * copyright notice, this list of conditions and the following disclaimer 12 * in the documentation and/or other materials provided with the 13 * distribution. 14 * * Neither the name of Google Inc. nor the names of its 15 * contributors may be used to endorse or promote products derived from 16 * this software without specific prior written permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 22 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 23 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 24 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 */ 30 31 #ifndef CrossThreadCopier_h 32 #define CrossThreadCopier_h 33 34 #include "platform/PlatformExport.h" 35 #include "wtf/Assertions.h" 36 #include "wtf/Forward.h" 37 #include "wtf/PassOwnPtr.h" 38 #include "wtf/PassRefPtr.h" 39 #include "wtf/RefPtr.h" 40 #include "wtf/ThreadSafeRefCounted.h" 41 #include "wtf/TypeTraits.h" 42 43 namespace WebCore { 44 45 class IntRect; 46 class IntSize; 47 class KURL; 48 class ResourceError; 49 class ResourceRequest; 50 class ResourceResponse; 51 struct CrossThreadResourceResponseData; 52 struct CrossThreadResourceRequestData; 53 struct ThreadableLoaderOptions; 54 55 template<typename T> struct CrossThreadCopierPassThrough { 56 typedef T Type; copyCrossThreadCopierPassThrough57 static Type copy(const T& parameter) 58 { 59 return parameter; 60 } 61 }; 62 63 template<bool isConvertibleToInteger, bool isThreadSafeRefCounted, typename T> struct CrossThreadCopierBase; 64 65 // Integers get passed through without any changes. 66 template<typename T> struct CrossThreadCopierBase<true, false, T> : public CrossThreadCopierPassThrough<T> { 67 }; 68 69 // To allow a type to be passed across threads using its copy constructor, add a forward declaration of the type and 70 // a CopyThreadCopierBase<false, false, TypeName> : public CrossThreadCopierPassThrough<TypeName> { }; to this file. 71 template<> struct CrossThreadCopierBase<false, false, ThreadableLoaderOptions> : public CrossThreadCopierPassThrough<ThreadableLoaderOptions> { 72 }; 73 74 template<> struct CrossThreadCopierBase<false, false, IntRect> : public CrossThreadCopierPassThrough<IntRect> { 75 }; 76 77 template<> struct CrossThreadCopierBase<false, false, IntSize> : public CrossThreadCopierPassThrough<IntSize> { 78 }; 79 80 // Custom copy methods. 81 template<typename T> struct CrossThreadCopierBase<false, true, T> { 82 typedef typename WTF::RemoveTemplate<T, RefPtr>::Type TypeWithoutRefPtr; 83 typedef typename WTF::RemoveTemplate<TypeWithoutRefPtr, PassRefPtr>::Type TypeWithoutPassRefPtr; 84 typedef typename WTF::RemovePointer<TypeWithoutPassRefPtr>::Type RefCountedType; 85 86 // Verify that only one of the above did a change. 87 COMPILE_ASSERT((WTF::IsSameType<RefPtr<RefCountedType>, T>::value 88 || WTF::IsSameType<PassRefPtr<RefCountedType>, T>::value 89 || WTF::IsSameType<RefCountedType*, T>::value), 90 OnlyAllowOneTypeModification); 91 92 typedef PassRefPtr<RefCountedType> Type; 93 static Type copy(const T& refPtr) 94 { 95 return refPtr; 96 } 97 }; 98 99 template<typename T> struct CrossThreadCopierBase<false, false, PassOwnPtr<T> > { 100 typedef PassOwnPtr<T> Type; 101 static Type copy(Type ownPtr) 102 { 103 return ownPtr; 104 } 105 }; 106 107 template<> struct CrossThreadCopierBase<false, false, KURL> { 108 typedef KURL Type; 109 PLATFORM_EXPORT static Type copy(const KURL&); 110 }; 111 112 template<> struct CrossThreadCopierBase<false, false, String> { 113 typedef String Type; 114 PLATFORM_EXPORT static Type copy(const String&); 115 }; 116 117 template<> struct CrossThreadCopierBase<false, false, ResourceError> { 118 typedef ResourceError Type; 119 PLATFORM_EXPORT static Type copy(const ResourceError&); 120 }; 121 122 template<> struct CrossThreadCopierBase<false, false, ResourceRequest> { 123 typedef PassOwnPtr<CrossThreadResourceRequestData> Type; 124 PLATFORM_EXPORT static Type copy(const ResourceRequest&); 125 }; 126 127 template<> struct CrossThreadCopierBase<false, false, ResourceResponse> { 128 typedef PassOwnPtr<CrossThreadResourceResponseData> Type; 129 PLATFORM_EXPORT static Type copy(const ResourceResponse&); 130 }; 131 132 template<typename T> struct CrossThreadCopier : public CrossThreadCopierBase<WTF::IsConvertibleToInteger<T>::value, 133 WTF::IsSubclassOfTemplate<typename WTF::RemoveTemplate<T, RefPtr>::Type, ThreadSafeRefCounted>::value 134 || WTF::IsSubclassOfTemplate<typename WTF::RemovePointer<T>::Type, ThreadSafeRefCounted>::value 135 || WTF::IsSubclassOfTemplate<typename WTF::RemoveTemplate<T, PassRefPtr>::Type, ThreadSafeRefCounted>::value, 136 T> { 137 }; 138 139 template<typename T> struct AllowCrossThreadAccessWrapper { 140 public: 141 explicit AllowCrossThreadAccessWrapper(T* value) : m_value(value) { } 142 T* value() const { return m_value; } 143 private: 144 T* m_value; 145 }; 146 147 template<typename T> struct CrossThreadCopierBase<false, false, AllowCrossThreadAccessWrapper<T> > { 148 typedef T* Type; 149 static Type copy(const AllowCrossThreadAccessWrapper<T>& wrapper) { return wrapper.value(); } 150 }; 151 152 template<typename T> AllowCrossThreadAccessWrapper<T> AllowCrossThreadAccess(T* value) 153 { 154 return AllowCrossThreadAccessWrapper<T>(value); 155 } 156 157 // FIXME: Move to a different header file. AllowAccessLater is for cross-thread access 158 // that is not cross-thread (tasks posted to a queue guaranteed to run on the same thread). 159 template<typename T> struct AllowAccessLaterWrapper { 160 public: 161 explicit AllowAccessLaterWrapper(T* value) : m_value(value) { } 162 T* value() const { return m_value; } 163 private: 164 T* m_value; 165 }; 166 167 template<typename T> struct CrossThreadCopierBase<false, false, AllowAccessLaterWrapper<T> > { 168 typedef T* Type; 169 static Type copy(const AllowAccessLaterWrapper<T>& wrapper) { return wrapper.value(); } 170 }; 171 172 template<typename T> AllowAccessLaterWrapper<T> AllowAccessLater(T* value) 173 { 174 return AllowAccessLaterWrapper<T>(value); 175 } 176 177 178 } // namespace WebCore 179 180 #endif // CrossThreadCopier_h 181