1 /* 2 * Copyright (C) 2006, 2007, 2008 Apple Inc. All rights reserved. 3 * 4 * This library is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU Library General Public 6 * License as published by the Free Software Foundation; either 7 * version 2 of the License, or (at your option) any later version. 8 * 9 * This library is distributed in the hope that it will be useful, 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 12 * Library General Public License for more details. 13 * 14 * You should have received a copy of the GNU Library General Public License 15 * along with this library; see the file COPYING.LIB. If not, write to 16 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, 17 * Boston, MA 02110-1301, USA. 18 * 19 */ 20 21 #ifndef WTF_VectorTraits_h 22 #define WTF_VectorTraits_h 23 24 #include "wtf/OwnPtr.h" 25 #include "wtf/RefPtr.h" 26 #include "wtf/TypeTraits.h" 27 #include <utility> 28 29 using std::pair; 30 31 namespace WTF { 32 33 class AtomicString; 34 35 template<typename T> 36 struct VectorTraitsBase 37 { 38 static const bool needsDestruction = !IsPod<T>::value; 39 static const bool canInitializeWithMemset = IsPod<T>::value; 40 static const bool canMoveWithMemcpy = IsPod<T>::value; 41 static const bool canCopyWithMemcpy = IsPod<T>::value; 42 static const bool canFillWithMemset = IsPod<T>::value && (sizeof(T) == sizeof(char)); 43 static const bool canCompareWithMemcmp = IsPod<T>::value; 44 template<typename U = void> 45 struct NeedsTracingLazily { 46 static const bool value = NeedsTracing<T>::value; 47 }; 48 static const WeakHandlingFlag weakHandlingFlag = NoWeakHandlingInCollections; // We don't support weak handling in vectors. 49 }; 50 51 template<typename T> 52 struct VectorTraits : VectorTraitsBase<T> { }; 53 54 // Classes marked with SimpleVectorTraits will use memmov, memcpy, memcmp 55 // instead of constructors, copy operators, etc for initialization, move 56 // and comparison. 57 template<typename T> 58 struct SimpleClassVectorTraits : VectorTraitsBase<T> 59 { 60 static const bool canInitializeWithMemset = true; 61 static const bool canMoveWithMemcpy = true; 62 static const bool canCompareWithMemcmp = true; 63 }; 64 65 // We know OwnPtr and RefPtr are simple enough that initializing to 0 and 66 // moving with memcpy (and then not destructing the original) will totally 67 // work. 68 template<typename P> 69 struct VectorTraits<RefPtr<P> > : SimpleClassVectorTraits<RefPtr<P> > { }; 70 71 template<typename P> 72 struct VectorTraits<OwnPtr<P> > : SimpleClassVectorTraits<OwnPtr<P> > { }; 73 74 template<typename First, typename Second> 75 struct VectorTraits<pair<First, Second> > 76 { 77 typedef VectorTraits<First> FirstTraits; 78 typedef VectorTraits<Second> SecondTraits; 79 80 static const bool needsDestruction = FirstTraits::needsDestruction || SecondTraits::needsDestruction; 81 static const bool canInitializeWithMemset = FirstTraits::canInitializeWithMemset && SecondTraits::canInitializeWithMemset; 82 static const bool canMoveWithMemcpy = FirstTraits::canMoveWithMemcpy && SecondTraits::canMoveWithMemcpy; 83 static const bool canCopyWithMemcpy = FirstTraits::canCopyWithMemcpy && SecondTraits::canCopyWithMemcpy; 84 static const bool canFillWithMemset = false; 85 static const bool canCompareWithMemcmp = FirstTraits::canCompareWithMemcmp && SecondTraits::canCompareWithMemcmp; 86 template <typename U = void> 87 struct NeedsTracingLazily { 88 static const bool value = ShouldBeTraced<FirstTraits>::value || ShouldBeTraced<SecondTraits>::value; 89 }; 90 static const WeakHandlingFlag weakHandlingFlag = NoWeakHandlingInCollections; // We don't support weak handling in vectors. 91 }; 92 93 } // namespace WTF 94 95 #define WTF_ALLOW_MOVE_INIT_AND_COMPARE_WITH_MEM_FUNCTIONS(ClassName) \ 96 namespace WTF { \ 97 template<> \ 98 struct VectorTraits<ClassName> : SimpleClassVectorTraits<ClassName> { }; \ 99 } 100 101 #define WTF_ALLOW_MOVE_AND_INIT_WITH_MEM_FUNCTIONS(ClassName) \ 102 namespace WTF { \ 103 template<> \ 104 struct VectorTraits<ClassName> : VectorTraitsBase<ClassName> \ 105 { \ 106 static const bool canInitializeWithMemset = true; \ 107 static const bool canMoveWithMemcpy = true; \ 108 }; \ 109 } 110 111 #define WTF_ALLOW_INIT_WITH_MEM_FUNCTIONS(ClassName) \ 112 namespace WTF { \ 113 template<> \ 114 struct VectorTraits<ClassName> : VectorTraitsBase<ClassName> \ 115 { \ 116 static const bool canInitializeWithMemset = true; \ 117 }; \ 118 } 119 120 using WTF::VectorTraits; 121 using WTF::SimpleClassVectorTraits; 122 123 #endif // WTF_VectorTraits_h 124