wtf/RefPtr.h

   1 /*
   2  *  Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
   3  *
   4  *  This library is free software; you can redistribute it and/or
   5  *  modify it under the terms of the GNU Library General Public
   6  *  License as published by the Free Software Foundation; either
   7  *  version 2 of the License, or (at your option) any later version.
   8  *
   9  *  This library is distributed in the hope that it will be useful,
  10  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  *  Library General Public License for more details.
  13  *
  14  *  You should have received a copy of the GNU Library General Public License
  15  *  along with this library; see the file COPYING.LIB.  If not, write to
  16  *  the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  17  *  Boston, MA 02110-1301, USA.
  18  *
  19  */
  20
  21 // RefPtr and PassRefPtr are documented at http://webkit.org/coding/RefPtr.html
  22
  23 #ifndef WTF_RefPtr_h
  24 #define WTF_RefPtr_h
  25
  26 #include <algorithm>
  27 #include "FastAllocBase.h"
  28 #include "PassRefPtr.h"
  29
  30 namespace WTF {
  31
  32     enum PlacementNewAdoptType { PlacementNewAdopt };
  33
  34     template<typename T> class PassRefPtr;
  35     template<typename T> class NonNullPassRefPtr;
  36
  37     enum HashTableDeletedValueType { HashTableDeletedValue };
  38
  39     template<typename T> class RefPtr {
  40         WTF_MAKE_FAST_ALLOCATED;
  41     public:
  42         ALWAYS_INLINE RefPtr() : m_ptr(0) { }
  43         ALWAYS_INLINE RefPtr(T* ptr) : m_ptr(ptr) { refIfNotNull(ptr); }
  44         ALWAYS_INLINE RefPtr(const RefPtr& o) : m_ptr(o.m_ptr) { refIfNotNull(m_ptr); }
  45         template<typename U> RefPtr(const RefPtr<U>& o) : m_ptr(o.get()) { refIfNotNull(m_ptr); }
  46
  47         // See comments in PassRefPtr.h for an explanation of why these takes const references.
  48         template<typename U> RefPtr(const PassRefPtr<U>&);
  49         template<typename U> RefPtr(const NonNullPassRefPtr<U>&);
  50
  51         // Special constructor for cases where we overwrite an object in place.
  52         ALWAYS_INLINE RefPtr(PlacementNewAdoptType) { }
  53
  54         // Hash table deleted values, which are only constructed and never copied or destroyed.
  55         RefPtr(HashTableDeletedValueType) : m_ptr(hashTableDeletedValue()) { }
  56         bool isHashTableDeletedValue() const { return m_ptr == hashTableDeletedValue(); }
  57
  58         ALWAYS_INLINE ~RefPtr() { derefIfNotNull(m_ptr); }
  59
  60         T* get() const { return m_ptr; }
  61
  62         void clear();
  63         PassRefPtr<T> release() { PassRefPtr<T> tmp = adoptRef(m_ptr); m_ptr = 0; return tmp; }
  64
  65         T& operator*() const { return *m_ptr; }
  66         ALWAYS_INLINE T* operator->() const { return m_ptr; }
  67
  68         bool operator!() const { return !m_ptr; }
  69
  70         // This conversion operator allows implicit conversion to bool but not to other integer types.
  71         typedef T* (RefPtr::*UnspecifiedBoolType);
  72         operator UnspecifiedBoolType() const { return m_ptr ? &RefPtr::m_ptr : 0; }
  73
  74         RefPtr& operator=(const RefPtr&);
  75         RefPtr& operator=(T*);
  76         RefPtr& operator=(const PassRefPtr<T>&);
  77         RefPtr& operator=(const NonNullPassRefPtr<T>&);
  78 #if !HAVE(NULLPTR)
  79         RefPtr& operator=(std::nullptr_t) { clear(); return *this; }
  80 #endif
  81         template<typename U> RefPtr& operator=(const RefPtr<U>&);
  82         template<typename U> RefPtr& operator=(const PassRefPtr<U>&);
  83         template<typename U> RefPtr& operator=(const NonNullPassRefPtr<U>&);
  84
  85         void swap(RefPtr&);
  86
  87         static T* hashTableDeletedValue() { return reinterpret_cast<T*>(-1); }
  88
  89     private:
  90         T* m_ptr;
  91     };
  92
  93     template<typename T> template<typename U> inline RefPtr<T>::RefPtr(const PassRefPtr<U>& o)
  94         : m_ptr(o.leakRef())
  95     {
  96     }
  97
  98     template<typename T> template<typename U> inline RefPtr<T>::RefPtr(const NonNullPassRefPtr<U>& o)
  99         : m_ptr(o.leakRef())
 100     {
 101     }
 102
 103     template<typename T> inline void RefPtr<T>::clear()
 104     {
 105         T* ptr = m_ptr;
 106         m_ptr = 0;
 107         derefIfNotNull(ptr);
 108     }
 109
 110     template<typename T> inline RefPtr<T>& RefPtr<T>::operator=(const RefPtr<T>& o)
 111     {
 112         T* optr = o.get();
 113         refIfNotNull(optr);
 114         T* ptr = m_ptr;
 115         m_ptr = optr;
 116         derefIfNotNull(ptr);
 117         return *this;
 118     }
 119
 120     template<typename T> template<typename U> inline RefPtr<T>& RefPtr<T>::operator=(const RefPtr<U>& o)
 121     {
 122         T* optr = o.get();
 123         refIfNotNull(optr);
 124         T* ptr = m_ptr;
 125         m_ptr = optr;
 126         derefIfNotNull(ptr);
 127         return *this;
 128     }
 129
 130     template<typename T> inline RefPtr<T>& RefPtr<T>::operator=(T* optr)
 131     {
 132         refIfNotNull(optr);
 133         T* ptr = m_ptr;
 134         m_ptr = optr;
 135         derefIfNotNull(ptr);
 136         return *this;
 137     }
 138
 139     template<typename T> inline RefPtr<T>& RefPtr<T>::operator=(const PassRefPtr<T>& o)
 140     {
 141         T* ptr = m_ptr;
 142         m_ptr = o.leakRef();
 143         derefIfNotNull(ptr);
 144         return *this;
 145     }
 146
 147     template<typename T> inline RefPtr<T>& RefPtr<T>::operator=(const NonNullPassRefPtr<T>& o)
 148     {
 149         T* ptr = m_ptr;
 150         m_ptr = o.leakRef();
 151         derefIfNotNull(ptr);
 152         return *this;
 153     }
 154
 155     template<typename T> template<typename U> inline RefPtr<T>& RefPtr<T>::operator=(const PassRefPtr<U>& o)
 156     {
 157         T* ptr = m_ptr;
 158         m_ptr = o.leakRef();
 159         derefIfNotNull(ptr);
 160         return *this;
 161     }
 162
 163     template<typename T> template<typename U> inline RefPtr<T>& RefPtr<T>::operator=(const NonNullPassRefPtr<U>& o)
 164     {
 165         T* ptr = m_ptr;
 166         m_ptr = o.leakRef();
 167         derefIfNotNull(ptr);
 168         return *this;
 169     }
 170
 171     template<class T> inline void RefPtr<T>::swap(RefPtr<T>& o)
 172     {
 173         std::swap(m_ptr, o.m_ptr);
 174     }
 175
 176     template<class T> inline void swap(RefPtr<T>& a, RefPtr<T>& b)
 177     {
 178         a.swap(b);
 179     }
 180
 181     template<typename T, typename U> inline bool operator==(const RefPtr<T>& a, const RefPtr<U>& b)
 182     {
 183         return a.get() == b.get();
 184     }
 185
 186     template<typename T, typename U> inline bool operator==(const RefPtr<T>& a, U* b)
 187     {
 188         return a.get() == b;
 189     }
 190
 191     template<typename T, typename U> inline bool operator==(T* a, const RefPtr<U>& b)
 192     {
 193         return a == b.get();
 194     }
 195
 196     template<typename T, typename U> inline bool operator!=(const RefPtr<T>& a, const RefPtr<U>& b)
 197     {
 198         return a.get() != b.get();
 199     }
 200
 201     template<typename T, typename U> inline bool operator!=(const RefPtr<T>& a, U* b)
 202     {
 203         return a.get() != b;
 204     }
 205
 206     template<typename T, typename U> inline bool operator!=(T* a, const RefPtr<U>& b)
 207     {
 208         return a != b.get();
 209     }
 210
 211     template<typename T, typename U> inline RefPtr<T> static_pointer_cast(const RefPtr<U>& p)
 212     {
 213         return RefPtr<T>(static_cast<T*>(p.get()));
 214     }
 215
 216     template<typename T, typename U> inline RefPtr<T> const_pointer_cast(const RefPtr<U>& p)
 217     {
 218         return RefPtr<T>(const_cast<T*>(p.get()));
 219     }
 220
 221     template<typename T> inline T* getPtr(const RefPtr<T>& p)
 222     {
 223         return p.get();
 224     }
 225
 226 } // namespace WTF
 227
 228 using WTF::RefPtr;
 229 using WTF::static_pointer_cast;
 230 using WTF::const_pointer_cast;
 231
 232 #endif // WTF_RefPtr_h