1/* 2 * Copyright (C) 2009, 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_PassOwnPtr_h 27#define WTF_PassOwnPtr_h 28 29#include "wtf/Assertions.h" 30#include "wtf/NullPtr.h" 31#include "wtf/OwnPtrCommon.h" 32#include "wtf/TypeTraits.h" 33 34namespace WTF { 35 36 // Unlike most of our smart pointers, PassOwnPtr can take either the pointer type or the pointed-to type. 37 38 template<typename T> class OwnPtr; 39 template<typename T> class PassOwnPtr; 40 template<typename T> PassOwnPtr<T> adoptPtr(T*); 41 42 template<typename T> class PassOwnPtr { 43 WTF_DISALLOW_CONSTRUCTION_FROM_ZERO(PassOwnPtr); 44 public: 45 typedef typename RemovePointer<T>::Type ValueType; 46 typedef ValueType* PtrType; 47 48 PassOwnPtr() : m_ptr(0) { } 49 PassOwnPtr(std::nullptr_t) : m_ptr(0) { } 50 51 // It somewhat breaks the type system to allow transfer of ownership out of 52 // a const PassOwnPtr. However, it makes it much easier to work with PassOwnPtr 53 // temporaries, and we don't have a need to use real const PassOwnPtrs anyway. 54 PassOwnPtr(const PassOwnPtr& o) : m_ptr(o.leakPtr()) { } 55 template<typename U> PassOwnPtr(const PassOwnPtr<U>& o) : m_ptr(o.leakPtr()) { } 56 57 ~PassOwnPtr() { deleteOwnedPtr(m_ptr); } 58 59 PtrType get() const { return m_ptr; } 60 61 PtrType leakPtr() const WARN_UNUSED_RETURN; 62 63 ValueType& operator*() const { ASSERT(m_ptr); return *m_ptr; } 64 PtrType operator->() const { ASSERT(m_ptr); return m_ptr; } 65 66 bool operator!() const { return !m_ptr; } 67 68 // This conversion operator allows implicit conversion to bool but not to other integer types. 69 typedef PtrType PassOwnPtr::*UnspecifiedBoolType; 70 operator UnspecifiedBoolType() const { return m_ptr ? &PassOwnPtr::m_ptr : 0; } 71 72 PassOwnPtr& operator=(const PassOwnPtr&) { COMPILE_ASSERT(!sizeof(T*), PassOwnPtr_should_never_be_assigned_to); return *this; } 73 74 template<typename U> friend PassOwnPtr<U> adoptPtr(U*); 75 76 private: 77 explicit PassOwnPtr(PtrType ptr) : m_ptr(ptr) { } 78 79 // We should never have two OwnPtrs for the same underlying object (otherwise we'll get 80 // double-destruction), so these equality operators should never be needed. 81 template<typename U> bool operator==(const PassOwnPtr<U>&) { COMPILE_ASSERT(!sizeof(U*), OwnPtrs_should_never_be_equal); return false; } 82 template<typename U> bool operator!=(const PassOwnPtr<U>&) { COMPILE_ASSERT(!sizeof(U*), OwnPtrs_should_never_be_equal); return false; } 83 template<typename U> bool operator==(const OwnPtr<U>&) { COMPILE_ASSERT(!sizeof(U*), OwnPtrs_should_never_be_equal); return false; } 84 template<typename U> bool operator!=(const OwnPtr<U>&) { COMPILE_ASSERT(!sizeof(U*), OwnPtrs_should_never_be_equal); return false; } 85 86 mutable PtrType m_ptr; 87 }; 88 89 template<typename T> inline typename PassOwnPtr<T>::PtrType PassOwnPtr<T>::leakPtr() const 90 { 91 PtrType ptr = m_ptr; 92 m_ptr = 0; 93 return ptr; 94 } 95 96 template<typename T, typename U> inline bool operator==(const PassOwnPtr<T>& a, const PassOwnPtr<U>& b) 97 { 98 return a.get() == b.get(); 99 } 100 101 template<typename T, typename U> inline bool operator==(const PassOwnPtr<T>& a, const OwnPtr<U>& b) 102 { 103 return a.get() == b.get(); 104 } 105 106 template<typename T, typename U> inline bool operator==(const OwnPtr<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, U* b) 112 { 113 return a.get() == b; 114 } 115 116 template<typename T, typename U> inline bool operator==(T* a, const PassOwnPtr<U>& b) 117 { 118 return a == b.get(); 119 } 120 121 template<typename T, typename U> inline bool operator!=(const PassOwnPtr<T>& a, const PassOwnPtr<U>& b) 122 { 123 return a.get() != b.get(); 124 } 125 126 template<typename T, typename U> inline bool operator!=(const PassOwnPtr<T>& a, const OwnPtr<U>& b) 127 { 128 return a.get() != b.get(); 129 } 130 131 template<typename T, typename U> inline bool operator!=(const OwnPtr<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, U* b) 137 { 138 return a.get() != b; 139 } 140 141 template<typename T, typename U> inline bool operator!=(T* a, const PassOwnPtr<U>& b) 142 { 143 return a != b.get(); 144 } 145 146 template<typename T> inline PassOwnPtr<T> adoptPtr(T* ptr) 147 { 148 return PassOwnPtr<T>(ptr); 149 } 150 151 template<typename T, typename U> inline PassOwnPtr<T> static_pointer_cast(const PassOwnPtr<U>& p) 152 { 153 return adoptPtr(static_cast<T*>(p.leakPtr())); 154 } 155 156 template<typename T, typename U> inline PassOwnPtr<T> const_pointer_cast(const PassOwnPtr<U>& p) 157 { 158 return adoptPtr(const_cast<T*>(p.leakPtr())); 159 } 160 161 template<typename T> inline T* getPtr(const PassOwnPtr<T>& p) 162 { 163 return p.get(); 164 } 165 166} // namespace WTF 167 168using WTF::PassOwnPtr; 169using WTF::adoptPtr; 170using WTF::const_pointer_cast; 171using WTF::static_pointer_cast; 172 173#endif // WTF_PassOwnPtr_h 174