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 "platform/heap/Handle.h" 36 #include "wtf/Assertions.h" 37 #include "wtf/Forward.h" 38 #include "wtf/PassOwnPtr.h" 39 #include "wtf/PassRefPtr.h" 40 #include "wtf/RawPtr.h" 41 #include "wtf/RefPtr.h" 42 #include "wtf/ThreadSafeRefCounted.h" 43 #include "wtf/TypeTraits.h" 44 45 namespace blink { 46 47 class IntRect; 48 class IntSize; 49 class KURL; 50 class ResourceError; 51 class ResourceRequest; 52 class ResourceResponse; 53 struct CrossThreadResourceResponseData; 54 struct CrossThreadResourceRequestData; 55 56 template<typename T> struct CrossThreadCopierPassThrough { 57 typedef T Type; copyCrossThreadCopierPassThrough58 static Type copy(const T& parameter) 59 { 60 return parameter; 61 } 62 }; 63 64 template<bool isConvertibleToInteger, bool isThreadSafeRefCounted, bool isGarbageCollected, typename T> struct CrossThreadCopierBase; 65 66 // Integers get passed through without any changes. 67 template<typename T> struct CrossThreadCopierBase<true, false, false, T> : public CrossThreadCopierPassThrough<T> { 68 }; 69 70 // To allow a type to be passed across threads using its copy constructor, add a forward declaration of the type and 71 // a CopyThreadCopierBase<false, false, TypeName> : public CrossThreadCopierPassThrough<TypeName> { }; to this file. 72 template<> struct CrossThreadCopierBase<false, false, false, IntRect> : public CrossThreadCopierPassThrough<IntRect> { 73 }; 74 75 template<> struct CrossThreadCopierBase<false, false, false, IntSize> : public CrossThreadCopierPassThrough<IntSize> { 76 }; 77 78 // Custom copy methods. 79 template<typename T> struct CrossThreadCopierBase<false, true, false, T> { 80 typedef typename WTF::RemoveTemplate<T, RefPtr>::Type TypeWithoutRefPtr; 81 typedef typename WTF::RemoveTemplate<TypeWithoutRefPtr, PassRefPtr>::Type TypeWithoutPassRefPtr; 82 typedef typename WTF::RemovePointer<TypeWithoutPassRefPtr>::Type RefCountedType; 83 84 // Verify that only one of the above did a change. 85 COMPILE_ASSERT((WTF::IsSameType<RefPtr<RefCountedType>, T>::value 86 || WTF::IsSameType<PassRefPtr<RefCountedType>, T>::value 87 || WTF::IsSameType<RefCountedType*, T>::value), 88 OnlyAllowOneTypeModification); 89 90 typedef PassRefPtr<RefCountedType> Type; 91 static Type copy(const T& refPtr) 92 { 93 return refPtr; 94 } 95 }; 96 97 template<typename T> struct CrossThreadCopierBase<false, false, false, PassOwnPtr<T> > { 98 typedef PassOwnPtr<T> Type; 99 static Type copy(Type ownPtr) 100 { 101 return ownPtr; 102 } 103 }; 104 105 template<typename T> struct CrossThreadCopierBase<false, false, false, WeakMember<T>*> { 106 typedef WeakMember<T>* Type; 107 static Type copy(Type ptr) 108 { 109 return ptr; 110 } 111 }; 112 113 template<> struct CrossThreadCopierBase<false, false, false, KURL> { 114 typedef KURL Type; 115 PLATFORM_EXPORT static Type copy(const KURL&); 116 }; 117 118 template<> struct CrossThreadCopierBase<false, false, false, String> { 119 typedef String Type; 120 PLATFORM_EXPORT static Type copy(const String&); 121 }; 122 123 template<> struct CrossThreadCopierBase<false, false, false, ResourceError> { 124 typedef ResourceError Type; 125 PLATFORM_EXPORT static Type copy(const ResourceError&); 126 }; 127 128 template<> struct CrossThreadCopierBase<false, false, false, ResourceRequest> { 129 typedef PassOwnPtr<CrossThreadResourceRequestData> Type; 130 PLATFORM_EXPORT static Type copy(const ResourceRequest&); 131 }; 132 133 template<> struct CrossThreadCopierBase<false, false, false, ResourceResponse> { 134 typedef PassOwnPtr<CrossThreadResourceResponseData> Type; 135 PLATFORM_EXPORT static Type copy(const ResourceResponse&); 136 }; 137 138 template<typename T> struct CrossThreadCopierBase<false, false, true, T> { 139 typedef typename WTF::RemovePointer<T>::Type TypeWithoutPointer; 140 typedef RawPtr<TypeWithoutPointer> Type; 141 static Type copy(const T& ptr) 142 { 143 return ptr; 144 } 145 }; 146 147 template<typename T> struct CrossThreadCopierBase<false, false, true, RawPtr<T> > { 148 typedef RawPtr<T> Type; 149 static Type copy(const Type& ptr) 150 { 151 return ptr; 152 } 153 }; 154 155 template<typename T> struct CrossThreadCopierBase<false, false, true, Member<T> > { 156 typedef RawPtr<T> Type; 157 static Type copy(const Member<T>& ptr) 158 { 159 return ptr; 160 } 161 }; 162 163 template<typename T> struct CrossThreadCopierBase<false, false, true, WeakMember<T> > { 164 typedef RawPtr<T> Type; 165 static Type copy(const WeakMember<T>& ptr) 166 { 167 return ptr; 168 } 169 }; 170 171 template<typename T> struct CrossThreadCopier : public CrossThreadCopierBase<WTF::IsConvertibleToInteger<T>::value, 172 WTF::IsSubclassOfTemplate<typename WTF::RemoveTemplate<T, RefPtr>::Type, ThreadSafeRefCounted>::value 173 || WTF::IsSubclassOfTemplate<typename WTF::RemovePointer<T>::Type, ThreadSafeRefCounted>::value 174 || WTF::IsSubclassOfTemplate<typename WTF::RemoveTemplate<T, PassRefPtr>::Type, ThreadSafeRefCounted>::value, 175 WTF::IsSubclassOfTemplate<typename WTF::RemovePointer<T>::Type, GarbageCollected>::value 176 || WTF::IsSubclassOfTemplate<typename WTF::RemoveTemplate<T, RawPtr>::Type, GarbageCollected>::value 177 || WTF::IsSubclassOfTemplate<typename WTF::RemoveTemplate<T, Member>::Type, GarbageCollected>::value 178 || WTF::IsSubclassOfTemplate<typename WTF::RemoveTemplate<T, WeakMember>::Type, GarbageCollected>::value, 179 T> { 180 }; 181 182 template<typename T> struct AllowCrossThreadAccessWrapper { 183 STACK_ALLOCATED(); 184 public: 185 explicit AllowCrossThreadAccessWrapper(T* value) : m_value(value) { } 186 T* value() const { return m_value; } 187 private: 188 // This raw pointer is safe since AllowCrossThreadAccessWrapper is 189 // always stack-allocated. Ideally this should be Member<T> if T is 190 // garbage-collected and T* otherwise, but we don't want to introduce 191 // another template magic just for distinguishing Member<T> from T*. 192 // From the perspective of GC, T* always works correctly. 193 GC_PLUGIN_IGNORE("") 194 T* m_value; 195 }; 196 197 template<typename T> struct CrossThreadCopierBase<false, false, false, AllowCrossThreadAccessWrapper<T> > { 198 typedef T* Type; 199 static Type copy(const AllowCrossThreadAccessWrapper<T>& wrapper) { return wrapper.value(); } 200 }; 201 202 template<typename T> AllowCrossThreadAccessWrapper<T> AllowCrossThreadAccess(T* value) 203 { 204 return AllowCrossThreadAccessWrapper<T>(value); 205 } 206 207 // FIXME: Move to a different header file. AllowAccessLater is for cross-thread access 208 // that is not cross-thread (tasks posted to a queue guaranteed to run on the same thread). 209 template<typename T> struct AllowAccessLaterWrapper { 210 public: 211 explicit AllowAccessLaterWrapper(T* value) : m_value(value) { } 212 T* value() const { return m_value; } 213 private: 214 T* m_value; 215 }; 216 217 template<typename T> struct CrossThreadCopierBase<false, false, false, AllowAccessLaterWrapper<T> > { 218 typedef T* Type; 219 static Type copy(const AllowAccessLaterWrapper<T>& wrapper) { return wrapper.value(); } 220 }; 221 222 template<typename T> AllowAccessLaterWrapper<T> AllowAccessLater(T* value) 223 { 224 return AllowAccessLaterWrapper<T>(value); 225 } 226 227 228 } // namespace blink 229 230 #endif // CrossThreadCopier_h 231