wtf/PassOwnArrayPtr.h

   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 "Assertions.h"
  30 #include "NullPtr.h"
  31 #include "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 public:
  42     typedef T* PtrType;
  43
  44     PassOwnArrayPtr() : m_ptr(0) { }
  45
  46 #if !defined(LOOSE_PASS_OWN_PTR) || !HAVE(NULLPTR)
  47     PassOwnArrayPtr(std::nullptr_t) : m_ptr(0) { }
  48 #endif
  49
  50     // It somewhat breaks the type system to allow transfer of ownership out of
  51     // a const PassOwnArrayPtr. However, it makes it much easier to work with PassOwnArrayPtr
  52     // temporaries, and we don't have a need to use real const PassOwnArrayPtrs anyway.
  53     PassOwnArrayPtr(const PassOwnArrayPtr& o) : m_ptr(o.leakPtr()) { }
  54     template<typename U> PassOwnArrayPtr(const PassOwnArrayPtr<U>& o) : m_ptr(o.leakPtr()) { }
  55
  56     ~PassOwnArrayPtr() { deleteOwnedArrayPtr(m_ptr); }
  57
  58     PtrType get() const { return m_ptr; }
  59
  60     void clear();
  61     PtrType leakPtr() const WARN_UNUSED_RETURN;
  62
  63     T& 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 #if COMPILER(WINSCW)
  70     operator bool() const { return m_ptr; }
  71 #else
  72     typedef PtrType PassOwnArrayPtr::*UnspecifiedBoolType;
  73     operator UnspecifiedBoolType() const { return m_ptr ? &PassOwnArrayPtr::m_ptr : 0; }
  74 #endif
  75
  76     PassOwnArrayPtr& operator=(const PassOwnArrayPtr<T>&);
  77 #if !defined(LOOSE_PASS_OWN_ARRAY_PTR) || !HAVE(NULLPTR)
  78     PassOwnArrayPtr& operator=(std::nullptr_t) { clear(); return *this; }
  79 #endif
  80     template<typename U> PassOwnArrayPtr& operator=(const PassOwnArrayPtr<U>&);
  81
  82     template<typename U> friend PassOwnArrayPtr<U> adoptArrayPtr(U*);
  83
  84 #ifdef LOOSE_PASS_OWN_ARRAY_PTR
  85     PassOwnArrayPtr(PtrType ptr) : m_ptr(ptr) { }
  86     PassOwnArrayPtr& operator=(PtrType);
  87 #endif
  88
  89 private:
  90 #ifndef LOOSE_PASS_OWN_ARRAY_PTR
  91     explicit PassOwnArrayPtr(PtrType ptr) : m_ptr(ptr) { }
  92 #endif
  93
  94     mutable PtrType m_ptr;
  95 };
  96
  97 template<typename T> inline void PassOwnArrayPtr<T>::clear()
  98 {
  99     PtrType ptr = m_ptr;
 100     m_ptr = 0;
 101     deleteOwnedArrayPtr(ptr);
 102 }
 103
 104 template<typename T> inline typename PassOwnArrayPtr<T>::PtrType PassOwnArrayPtr<T>::leakPtr() const
 105 {
 106     PtrType ptr = m_ptr;
 107     m_ptr = 0;
 108     return ptr;
 109 }
 110
 111 #ifdef LOOSE_PASS_OWN_ARRAY_PTR
 112 template<typename T> inline PassOwnArrayPtr<T>& PassOwnArrayPtr<T>::operator=(PtrType optr)
 113 {
 114     PtrType ptr = m_ptr;
 115     m_ptr = optr;
 116     ASSERT(!ptr || m_ptr != ptr);
 117     if (ptr)
 118         deleteOwnedArrayPtr(ptr);
 119     return *this;
 120 }
 121 #endif
 122
 123 template<typename T> inline PassOwnArrayPtr<T>& PassOwnArrayPtr<T>::operator=(const PassOwnArrayPtr<T>& optr)
 124 {
 125     PtrType ptr = m_ptr;
 126     m_ptr = optr.leakPtr();
 127     ASSERT(!ptr || m_ptr != ptr);
 128     if (ptr)
 129         deleteOwnedArrayPtr(ptr);
 130     return *this;
 131 }
 132
 133 template<typename T> template<typename U> inline PassOwnArrayPtr<T>& PassOwnArrayPtr<T>::operator=(const PassOwnArrayPtr<U>& optr)
 134 {
 135     PtrType ptr = m_ptr;
 136     m_ptr = optr.leakPtr();
 137     ASSERT(!ptr || m_ptr != ptr);
 138     if (ptr)
 139         deleteOwnedArrayPtr(ptr);
 140     return *this;
 141 }
 142
 143 template<typename T, typename U> inline bool operator==(const PassOwnArrayPtr<T>& a, const PassOwnArrayPtr<U>& b)
 144 {
 145     return a.get() == b.get();
 146 }
 147
 148 template<typename T, typename U> inline bool operator==(const PassOwnArrayPtr<T>& a, const OwnArrayPtr<U>& b)
 149 {
 150     return a.get() == b.get();
 151 }
 152
 153 template<typename T, typename U> inline bool operator==(const OwnArrayPtr<T>& a, const PassOwnArrayPtr<U>& b)
 154 {
 155     return a.get() == b.get();
 156 }
 157
 158 template<typename T, typename U> inline bool operator==(const PassOwnArrayPtr<T>& a, U* b)
 159 {
 160     return a.get() == b;
 161 }
 162
 163 template<typename T, typename U> inline bool operator==(T* a, const PassOwnArrayPtr<U>& b)
 164 {
 165     return a == b.get();
 166 }
 167
 168 template<typename T, typename U> inline bool operator!=(const PassOwnArrayPtr<T>& a, const PassOwnArrayPtr<U>& b)
 169 {
 170     return a.get() != b.get();
 171 }
 172
 173 template<typename T, typename U> inline bool operator!=(const PassOwnArrayPtr<T>& a, const OwnArrayPtr<U>& b)
 174 {
 175     return a.get() != b.get();
 176 }
 177
 178 template<typename T, typename U> inline bool operator!=(const OwnArrayPtr<T>& a, const PassOwnArrayPtr<U>& b)
 179 {
 180     return a.get() != b.get();
 181 }
 182
 183 template<typename T, typename U> inline bool operator!=(const PassOwnArrayPtr<T>& a, U* b)
 184 {
 185     return a.get() != b;
 186 }
 187
 188 template<typename T, typename U> inline bool operator!=(T* a, const PassOwnArrayPtr<U>& b)
 189 {
 190     return a != b.get();
 191 }
 192
 193 template<typename T> inline PassOwnArrayPtr<T> adoptArrayPtr(T* ptr)
 194 {
 195     return PassOwnArrayPtr<T>(ptr);
 196 }
 197
 198 template<typename T> inline void deleteOwnedArrayPtr(T* ptr)
 199 {
 200     typedef char known[sizeof(T) ? 1 : -1];
 201     if (sizeof(known))
 202         delete [] ptr;
 203 }
 204
 205 template<typename T, typename U> inline PassOwnArrayPtr<T> static_pointer_cast(const PassOwnArrayPtr<U>& p)
 206 {
 207     return adoptArrayPtr(static_cast<T*>(p.leakPtr()));
 208 }
 209
 210 template<typename T, typename U> inline PassOwnArrayPtr<T> const_pointer_cast(const PassOwnArrayPtr<U>& p)
 211 {
 212     return adoptArrayPtr(const_cast<T*>(p.leakPtr()));
 213 }
 214
 215 template<typename T> inline T* getPtr(const PassOwnArrayPtr<T>& p)
 216 {
 217     return p.get();
 218 }
 219
 220 } // namespace WTF
 221
 222 using WTF::PassOwnArrayPtr;
 223 using WTF::adoptArrayPtr;
 224 using WTF::const_pointer_cast;
 225 using WTF::static_pointer_cast;
 226
 227 #endif // WTF_PassOwnArrayPtr_h