1 /* 2 * Copyright (C) 2010 Apple 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 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY 14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR 17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY 21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 24 */ 25 26 #ifndef WTF_PassOwnArrayPtr_h 27 #define WTF_PassOwnArrayPtr_h 28 29 #include "wtf/Assertions.h" 30 #include "wtf/NullPtr.h" 31 #include "wtf/TypeTraits.h" 32 33 namespace WTF { 34 35 template<typename T> class OwnArrayPtr; 36 template<typename T> class PassOwnArrayPtr; 37 template<typename T> PassOwnArrayPtr<T> adoptArrayPtr(T*); 38 template<typename T> void deleteOwnedArrayPtr(T* ptr); 39 40 template<typename T> class PassOwnArrayPtr { 41 WTF_DISALLOW_CONSTRUCTION_FROM_ZERO(PassOwnArrayPtr); 42 public: 43 typedef T* PtrType; 44 45 PassOwnArrayPtr() : m_ptr(0) { } 46 PassOwnArrayPtr(std::nullptr_t) : m_ptr(0) { } 47 48 // It somewhat breaks the type system to allow transfer of ownership out of 49 // a const PassOwnArrayPtr. However, it makes it much easier to work with PassOwnArrayPtr 50 // temporaries, and we don't have a need to use real const PassOwnArrayPtrs anyway. 51 PassOwnArrayPtr(const PassOwnArrayPtr& o) : m_ptr(o.leakPtr()) { } 52 template<typename U> PassOwnArrayPtr(const PassOwnArrayPtr<U>& o) : m_ptr(o.leakPtr()) { } 53 54 ~PassOwnArrayPtr() { deleteOwnedArrayPtr(m_ptr); } 55 56 PtrType get() const { return m_ptr; } 57 58 PtrType leakPtr() const WARN_UNUSED_RETURN; 59 60 T& operator*() const { ASSERT(m_ptr); return *m_ptr; } 61 PtrType operator->() const { ASSERT(m_ptr); return m_ptr; } 62 63 bool operator!() const { return !m_ptr; } 64 65 // This conversion operator allows implicit conversion to bool but not to other integer types. 66 typedef PtrType PassOwnArrayPtr::*UnspecifiedBoolType; 67 operator UnspecifiedBoolType() const { return m_ptr ? &PassOwnArrayPtr::m_ptr : 0; } 68 69 PassOwnArrayPtr& operator=(const PassOwnArrayPtr&) { COMPILE_ASSERT(!sizeof(T*), PassOwnArrayPtr_should_never_be_assigned_to); return *this; } 70 71 template<typename U> friend PassOwnArrayPtr<U> adoptArrayPtr(U*); 72 73 private: 74 explicit PassOwnArrayPtr(PtrType ptr) : m_ptr(ptr) { } 75 76 mutable PtrType m_ptr; 77 }; 78 79 template<typename T> inline typename PassOwnArrayPtr<T>::PtrType PassOwnArrayPtr<T>::leakPtr() const 80 { 81 PtrType ptr = m_ptr; 82 m_ptr = 0; 83 return ptr; 84 } 85 86 template<typename T, typename U> inline bool operator==(const PassOwnArrayPtr<T>& a, const PassOwnArrayPtr<U>& b) 87 { 88 return a.get() == b.get(); 89 } 90 91 template<typename T, typename U> inline bool operator==(const PassOwnArrayPtr<T>& a, const OwnArrayPtr<U>& b) 92 { 93 return a.get() == b.get(); 94 } 95 96 template<typename T, typename U> inline bool operator==(const OwnArrayPtr<T>& a, const PassOwnArrayPtr<U>& b) 97 { 98 return a.get() == b.get(); 99 } 100 101 template<typename T, typename U> inline bool operator==(const PassOwnArrayPtr<T>& a, U* b) 102 { 103 return a.get() == b; 104 } 105 106 template<typename T, typename U> inline bool operator==(T* a, const PassOwnArrayPtr<U>& b) 107 { 108 return a == b.get(); 109 } 110 111 template<typename T, typename U> inline bool operator!=(const PassOwnArrayPtr<T>& a, const PassOwnArrayPtr<U>& b) 112 { 113 return a.get() != b.get(); 114 } 115 116 template<typename T, typename U> inline bool operator!=(const PassOwnArrayPtr<T>& a, const OwnArrayPtr<U>& b) 117 { 118 return a.get() != b.get(); 119 } 120 121 template<typename T, typename U> inline bool operator!=(const OwnArrayPtr<T>& a, const PassOwnArrayPtr<U>& b) 122 { 123 return a.get() != b.get(); 124 } 125 126 template<typename T, typename U> inline bool operator!=(const PassOwnArrayPtr<T>& a, U* b) 127 { 128 return a.get() != b; 129 } 130 131 template<typename T, typename U> inline bool operator!=(T* a, const PassOwnArrayPtr<U>& b) 132 { 133 return a != b.get(); 134 } 135 136 template<typename T> inline PassOwnArrayPtr<T> adoptArrayPtr(T* ptr) 137 { 138 return PassOwnArrayPtr<T>(ptr); 139 } 140 141 template<typename T> inline void deleteOwnedArrayPtr(T* ptr) 142 { 143 typedef char known[sizeof(T) ? 1 : -1]; 144 if (sizeof(known)) 145 delete [] ptr; 146 } 147 148 template<typename T, typename U> inline PassOwnArrayPtr<T> static_pointer_cast(const PassOwnArrayPtr<U>& p) 149 { 150 return adoptArrayPtr(static_cast<T*>(p.leakPtr())); 151 } 152 153 template<typename T, typename U> inline PassOwnArrayPtr<T> const_pointer_cast(const PassOwnArrayPtr<U>& p) 154 { 155 return adoptArrayPtr(const_cast<T*>(p.leakPtr())); 156 } 157 158 template<typename T> inline T* getPtr(const PassOwnArrayPtr<T>& p) 159 { 160 return p.get(); 161 } 162 163 } // namespace WTF 164 165 using WTF::PassOwnArrayPtr; 166 using WTF::adoptArrayPtr; 167 using WTF::const_pointer_cast; 168 using WTF::static_pointer_cast; 169 170 #endif // WTF_PassOwnArrayPtr_h 171
