third_party/WebKit/Source/wtf/OwnPtr.h

   1 /*
   2  *  Copyright (C) 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
   3  *  Copyright (C) 2013 Intel Corporation. All rights reserved.
   4  *
   5  *  This library is free software; you can redistribute it and/or
   6  *  modify it under the terms of the GNU Library General Public
   7  *  License as published by the Free Software Foundation; either
   8  *  version 2 of the License, or (at your option) any later version.
   9  *
  10  *  This library is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  *  Library General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU Library General Public License
  16  *  along with this library; see the file COPYING.LIB.  If not, write to
  17  *  the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  18  *  Boston, MA 02110-1301, USA.
  19  *
  20  */
  21
  22 #ifndef WTF_OwnPtr_h
  23 #define WTF_OwnPtr_h
  24
  25 #include "wtf/HashTableDeletedValueType.h"
  26 #include "wtf/Noncopyable.h"
  27 #include "wtf/NullPtr.h"
  28 #include "wtf/OwnPtrCommon.h"
  29 #include <algorithm>
  30 #include <utility>
  31
  32 namespace WTF {
  33
  34     template<typename T> class PassOwnPtr;
  35
  36     template<typename T> class OwnPtr {
  37         WTF_MAKE_NONCOPYABLE(OwnPtr);
  38     public:
  39         typedef typename RemoveExtent<T>::Type ValueType;
  40         typedef ValueType* PtrType;
  41
  42         OwnPtr() : m_ptr(0) { }
  43         OwnPtr(std::nullptr_t) : m_ptr(0) { }
  44
  45         // See comment in PassOwnPtr.h for why this takes a const reference.
  46         OwnPtr(const PassOwnPtr<T>&);
  47         template<typename U> OwnPtr(const PassOwnPtr<U>&, EnsurePtrConvertibleArgDecl(U, T));
  48
  49         // Hash table deleted values, which are only constructed and never copied or destroyed.
  50         OwnPtr(HashTableDeletedValueType) : m_ptr(hashTableDeletedValue()) { }
  51         bool isHashTableDeletedValue() const { return m_ptr == hashTableDeletedValue(); }
  52
  53         ~OwnPtr()
  54         {
  55             OwnedPtrDeleter<T>::deletePtr(m_ptr);
  56             m_ptr = 0;
  57         }
  58
  59         PtrType get() const { return m_ptr; }
  60
  61         void clear();
  62         PassOwnPtr<T> release();
  63         PtrType leakPtr() WARN_UNUSED_RETURN;
  64
  65         ValueType& operator*() const { ASSERT(m_ptr); return *m_ptr; }
  66         PtrType operator->() const { ASSERT(m_ptr); return m_ptr; }
  67
  68         ValueType& operator[](std::ptrdiff_t i) const;
  69
  70         bool operator!() const { return !m_ptr; }
  71
  72         // This conversion operator allows implicit conversion to bool but not to other integer types.
  73         typedef PtrType OwnPtr::*UnspecifiedBoolType;
  74         operator UnspecifiedBoolType() const { return m_ptr ? &OwnPtr::m_ptr : 0; }
  75
  76         OwnPtr& operator=(const PassOwnPtr<T>&);
  77         OwnPtr& operator=(std::nullptr_t) { clear(); return *this; }
  78         template<typename U> OwnPtr& operator=(const PassOwnPtr<U>&);
  79
  80         OwnPtr(OwnPtr&&);
  81         template<typename U> OwnPtr(OwnPtr<U>&&);
  82
  83         OwnPtr& operator=(OwnPtr&&);
  84         template<typename U> OwnPtr& operator=(OwnPtr<U>&&);
  85
  86         void swap(OwnPtr& o) { std::swap(m_ptr, o.m_ptr); }
  87
  88         static T* hashTableDeletedValue() { return reinterpret_cast<T*>(-1); }
  89
  90     private:
  91         // We should never have two OwnPtrs for the same underlying object (otherwise we'll get
  92         // double-destruction), so these equality operators should never be needed.
  93         template<typename U> bool operator==(const OwnPtr<U>&) const { static_assert(!sizeof(U*), "OwnPtrs should never be equal"); return false; }
  94         template<typename U> bool operator!=(const OwnPtr<U>&) const { static_assert(!sizeof(U*), "OwnPtrs should never be equal"); return false; }
  95         template<typename U> bool operator==(const PassOwnPtr<U>&) const { static_assert(!sizeof(U*), "OwnPtrs should never be equal"); return false; }
  96         template<typename U> bool operator!=(const PassOwnPtr<U>&) const { static_assert(!sizeof(U*), "OwnPtrs should never be equal"); return false; }
  97
  98         PtrType m_ptr;
  99     };
 100
 101     template<typename T> inline OwnPtr<T>::OwnPtr(const PassOwnPtr<T>& o)
 102         : m_ptr(o.leakPtr())
 103     {
 104     }
 105
 106     template<typename T> template<typename U> inline OwnPtr<T>::OwnPtr(const PassOwnPtr<U>& o, EnsurePtrConvertibleArgDefn(U, T))
 107         : m_ptr(o.leakPtr())
 108     {
 109         static_assert(!IsArray<T>::value, "pointers to array must never be converted");
 110     }
 111
 112     template<typename T> inline void OwnPtr<T>::clear()
 113     {
 114         PtrType ptr = m_ptr;
 115         m_ptr = 0;
 116         OwnedPtrDeleter<T>::deletePtr(ptr);
 117     }
 118
 119     template<typename T> inline PassOwnPtr<T> OwnPtr<T>::release()
 120     {
 121         PtrType ptr = m_ptr;
 122         m_ptr = 0;
 123         return PassOwnPtr<T>(ptr);
 124     }
 125
 126     template<typename T> inline typename OwnPtr<T>::PtrType OwnPtr<T>::leakPtr()
 127     {
 128         PtrType ptr = m_ptr;
 129         m_ptr = 0;
 130         return ptr;
 131     }
 132
 133     template<typename T> inline typename OwnPtr<T>::ValueType& OwnPtr<T>::operator[](std::ptrdiff_t i) const
 134     {
 135         static_assert(IsArray<T>::value, "elements access is possible for arrays only");
 136         ASSERT(m_ptr);
 137         ASSERT(i >= 0);
 138         return m_ptr[i];
 139     }
 140
 141     template<typename T> inline OwnPtr<T>& OwnPtr<T>::operator=(const PassOwnPtr<T>& o)
 142     {
 143         PtrType ptr = m_ptr;
 144         m_ptr = o.leakPtr();
 145         ASSERT(!ptr || m_ptr != ptr);
 146         OwnedPtrDeleter<T>::deletePtr(ptr);
 147         return *this;
 148     }
 149
 150     template<typename T> template<typename U> inline OwnPtr<T>& OwnPtr<T>::operator=(const PassOwnPtr<U>& o)
 151     {
 152         static_assert(!IsArray<T>::value, "pointers to array must never be converted");
 153         PtrType ptr = m_ptr;
 154         m_ptr = o.leakPtr();
 155         ASSERT(!ptr || m_ptr != ptr);
 156         OwnedPtrDeleter<T>::deletePtr(ptr);
 157         return *this;
 158     }
 159
 160     template<typename T> inline OwnPtr<T>::OwnPtr(OwnPtr<T>&& o)
 161         : m_ptr(o.leakPtr())
 162     {
 163     }
 164
 165     template<typename T> template<typename U> inline OwnPtr<T>::OwnPtr(OwnPtr<U>&& o)
 166         : m_ptr(o.leakPtr())
 167     {
 168         static_assert(!IsArray<T>::value, "pointers to array must never be converted");
 169     }
 170
 171     template<typename T> inline OwnPtr<T>& OwnPtr<T>::operator=(OwnPtr<T>&& o)
 172     {
 173         PtrType ptr = m_ptr;
 174         m_ptr = o.leakPtr();
 175         ASSERT(!ptr || m_ptr != ptr);
 176         OwnedPtrDeleter<T>::deletePtr(ptr);
 177
 178         return *this;
 179     }
 180
 181     template<typename T> template<typename U> inline OwnPtr<T>& OwnPtr<T>::operator=(OwnPtr<U>&& o)
 182     {
 183         static_assert(!IsArray<T>::value, "pointers to array must never be converted");
 184         PtrType ptr = m_ptr;
 185         m_ptr = o.leakPtr();
 186         ASSERT(!ptr || m_ptr != ptr);
 187         OwnedPtrDeleter<T>::deletePtr(ptr);
 188
 189         return *this;
 190     }
 191
 192     template<typename T> inline void swap(OwnPtr<T>& a, OwnPtr<T>& b)
 193     {
 194         a.swap(b);
 195     }
 196
 197     template<typename T, typename U> inline bool operator==(const OwnPtr<T>& a, U* b)
 198     {
 199         return a.get() == b;
 200     }
 201
 202     template<typename T, typename U> inline bool operator==(T* a, const OwnPtr<U>& b)
 203     {
 204         return a == b.get();
 205     }
 206
 207     template<typename T, typename U> inline bool operator!=(const OwnPtr<T>& a, U* b)
 208     {
 209         return a.get() != b;
 210     }
 211
 212     template<typename T, typename U> inline bool operator!=(T* a, const OwnPtr<U>& b)
 213     {
 214         return a != b.get();
 215     }
 216
 217     template<typename T> inline typename OwnPtr<T>::PtrType getPtr(const OwnPtr<T>& p)
 218     {
 219         return p.get();
 220     }
 221
 222 } // namespace WTF
 223
 224 using WTF::OwnPtr;
 225
 226 #endif // WTF_OwnPtr_h