1 /* 2 * Copyright (C) 2009 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_PassOwnPtr_h 27 #define WTF_PassOwnPtr_h 28 29 #include "Assertions.h" 30 #include "OwnPtrCommon.h" 31 #include "TypeTraits.h" 32 33 namespace WTF { 34 35 // Unlike most of our smart pointers, PassOwnPtr can take either the pointer type or the pointed-to type. 36 37 template <typename T> class OwnPtr; 38 39 template <typename T> class PassOwnPtr { 40 public: 41 typedef typename RemovePointer<T>::Type ValueType; 42 typedef ValueType* PtrType; 43 44 PassOwnPtr(PtrType ptr = 0) : m_ptr(ptr) { } 45 // It somewhat breaks the type system to allow transfer of ownership out of 46 // a const PassOwnPtr. However, it makes it much easier to work with PassOwnPtr 47 // temporaries, and we don't really have a need to use real const PassOwnPtrs 48 // anyway. 49 PassOwnPtr(const PassOwnPtr& o) : m_ptr(o.release()) { } 50 template <typename U> PassOwnPtr(const PassOwnPtr<U>& o) : m_ptr(o.release()) { } 51 52 ~PassOwnPtr() { deleteOwnedPtr(m_ptr); } 53 54 PtrType get() const { return m_ptr; } 55 56 void clear() { m_ptr = 0; } 57 PtrType release() const { PtrType ptr = m_ptr; m_ptr = 0; return ptr; } 58 59 ValueType& operator*() const { ASSERT(m_ptr); return *m_ptr; } 60 PtrType operator->() const { ASSERT(m_ptr); return m_ptr; } 61 62 bool operator!() const { return !m_ptr; } 63 64 // This conversion operator allows implicit conversion to bool but not to other integer types. 65 typedef PtrType PassOwnPtr::*UnspecifiedBoolType; 66 operator UnspecifiedBoolType() const { return m_ptr ? &PassOwnPtr::m_ptr : 0; } 67 68 PassOwnPtr& operator=(T*); 69 PassOwnPtr& operator=(const PassOwnPtr<T>&); 70 template <typename U> PassOwnPtr& operator=(const PassOwnPtr<U>&); 71 72 private: 73 mutable PtrType m_ptr; 74 }; 75 76 template <typename T> inline PassOwnPtr<T>& PassOwnPtr<T>::operator=(T* optr) 77 { 78 T* ptr = m_ptr; 79 m_ptr = optr; 80 ASSERT(!ptr || m_ptr != ptr); 81 if (ptr) 82 deleteOwnedPtr(ptr); 83 return *this; 84 } 85 86 template <typename T> inline PassOwnPtr<T>& PassOwnPtr<T>::operator=(const PassOwnPtr<T>& optr) 87 { 88 T* ptr = m_ptr; 89 m_ptr = optr.release(); 90 ASSERT(!ptr || m_ptr != ptr); 91 if (ptr) 92 deleteOwnedPtr(ptr); 93 return *this; 94 } 95 96 template <typename T> template <typename U> inline PassOwnPtr<T>& PassOwnPtr<T>::operator=(const PassOwnPtr<U>& optr) 97 { 98 T* ptr = m_ptr; 99 m_ptr = optr.release(); 100 ASSERT(!ptr || m_ptr != ptr); 101 if (ptr) 102 deleteOwnedPtr(ptr); 103 return *this; 104 } 105 106 template <typename T, typename U> inline bool operator==(const PassOwnPtr<T>& a, const PassOwnPtr<U>& b) 107 { 108 return a.get() == b.get(); 109 } 110 111 template <typename T, typename U> inline bool operator==(const PassOwnPtr<T>& a, const OwnPtr<U>& b) 112 { 113 return a.get() == b.get(); 114 } 115 116 template <typename T, typename U> inline bool operator==(const OwnPtr<T>& a, const PassOwnPtr<U>& b) 117 { 118 return a.get() == b.get(); 119 } 120 121 template <typename T, typename U> inline bool operator==(const PassOwnPtr<T>& a, U* b) 122 { 123 return a.get() == b; 124 } 125 126 template <typename T, typename U> inline bool operator==(T* a, const PassOwnPtr<U>& b) 127 { 128 return a == b.get(); 129 } 130 131 template <typename T, typename U> inline bool operator!=(const PassOwnPtr<T>& a, const PassOwnPtr<U>& b) 132 { 133 return a.get() != b.get(); 134 } 135 136 template <typename T, typename U> inline bool operator!=(const PassOwnPtr<T>& a, const OwnPtr<U>& b) 137 { 138 return a.get() != b.get(); 139 } 140 141 template <typename T, typename U> inline bool operator!=(const OwnPtr<T>& a, const PassOwnPtr<U>& b) 142 { 143 return a.get() != b.get(); 144 } 145 146 template <typename T, typename U> inline bool operator!=(const PassOwnPtr<T>& a, U* b) 147 { 148 return a.get() != b; 149 } 150 151 template <typename T, typename U> inline bool operator!=(T* a, const PassOwnPtr<U>& b) 152 { 153 return a != b.get(); 154 } 155 156 template <typename T, typename U> inline PassOwnPtr<T> static_pointer_cast(const PassOwnPtr<U>& p) 157 { 158 return PassOwnPtr<T>(static_cast<T*>(p.release())); 159 } 160 161 template <typename T, typename U> inline PassOwnPtr<T> const_pointer_cast(const PassOwnPtr<U>& p) 162 { 163 return PassOwnPtr<T>(const_cast<T*>(p.release())); 164 } 165 166 template <typename T> inline T* getPtr(const PassOwnPtr<T>& p) 167 { 168 return p.get(); 169 } 170 171 } // namespace WTF 172 173 using WTF::PassOwnPtr; 174 using WTF::const_pointer_cast; 175 using WTF::static_pointer_cast; 176 177 #endif // WTF_PassOwnPtr_h 178
