wtf/gobject/GRefPtr.h

   1 /*
   2  *  Copyright (C) 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
   3  *  Copyright (C) 2008 Collabora Ltd.
   4  *  Copyright (C) 2009 Martin Robinson
   5  *
   6  *  This library is free software; you can redistribute it and/or
   7  *  modify it under the terms of the GNU Library General Public
   8  *  License as published by the Free Software Foundation; either
   9  *  version 2 of the License, or (at your option) any later version.
  10  *
  11  *  This library is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  *  Library General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU Library General Public License
  17  *  along with this library; see the file COPYING.LIB.  If not, write to
  18  *  the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  19  *  Boston, MA 02110-1301, USA.
  20  *
  21  */
  22
  23 #ifndef WTF_GRefPtr_h
  24 #define WTF_GRefPtr_h
  25
  26 #include "AlwaysInline.h"
  27 #include <algorithm>
  28
  29 typedef struct _GHashTable GHashTable;
  30 typedef void* gpointer;
  31 extern "C" void g_object_unref(gpointer object);
  32 extern "C" gpointer  g_object_ref_sink(gpointer object);
  33
  34 namespace WTF {
  35
  36 enum GRefPtrAdoptType { GRefPtrAdopt };
  37 template <typename T> inline T* refGPtr(T*);
  38 template <typename T> inline void derefGPtr(T*);
  39 template <typename T> class GRefPtr;
  40 template <typename T> GRefPtr<T> adoptGRef(T*);
  41 template <> GHashTable* refGPtr(GHashTable* ptr);
  42 template <> void derefGPtr(GHashTable* ptr);
  43
  44 template <typename T> class GRefPtr {
  45 public:
  46     GRefPtr() : m_ptr(0) { }
  47     GRefPtr(T* ptr) : m_ptr(ptr) { if (ptr) refGPtr(ptr); }
  48     GRefPtr(const GRefPtr& o) : m_ptr(o.m_ptr) { if (T* ptr = m_ptr) refGPtr(ptr); }
  49     template <typename U> GRefPtr(const GRefPtr<U>& o) : m_ptr(o.get()) { if (T* ptr = m_ptr) refGPtr(ptr); }
  50
  51     ~GRefPtr() { if (T* ptr = m_ptr) derefGPtr(ptr); }
  52
  53     void clear()
  54     {
  55         if (T* ptr = m_ptr)
  56             derefGPtr(ptr);
  57         m_ptr = 0;
  58     }
  59
  60     T* get() const { return m_ptr; }
  61     T& operator*() const { return *m_ptr; }
  62     ALWAYS_INLINE T* operator->() const { return m_ptr; }
  63
  64     bool operator!() const { return !m_ptr; }
  65
  66     // This conversion operator allows implicit conversion to bool but not to other integer types.
  67     typedef T* GRefPtr::*UnspecifiedBoolType;
  68     operator UnspecifiedBoolType() const { return m_ptr ? &GRefPtr::m_ptr : 0; }
  69
  70     GRefPtr& operator=(const GRefPtr&);
  71     GRefPtr& operator=(T*);
  72     template <typename U> GRefPtr& operator=(const GRefPtr<U>&);
  73
  74     void swap(GRefPtr&);
  75     friend GRefPtr adoptGRef<T>(T*);
  76
  77 private:
  78     static T* hashTableDeletedValue() { return reinterpret_cast<T*>(-1); }
  79     // Adopting constructor.
  80     GRefPtr(T* ptr, GRefPtrAdoptType) : m_ptr(ptr) {}
  81
  82     T* m_ptr;
  83 };
  84
  85 template <typename T> inline GRefPtr<T>& GRefPtr<T>::operator=(const GRefPtr<T>& o)
  86 {
  87     T* optr = o.get();
  88     if (optr)
  89         refGPtr(optr);
  90     T* ptr = m_ptr;
  91     m_ptr = optr;
  92     if (ptr)
  93         derefGPtr(ptr);
  94     return *this;
  95 }
  96
  97 template <typename T> inline GRefPtr<T>& GRefPtr<T>::operator=(T* optr)
  98 {
  99     T* ptr = m_ptr;
 100     if (optr)
 101         refGPtr(optr);
 102     m_ptr = optr;
 103     if (ptr)
 104         derefGPtr(ptr);
 105     return *this;
 106 }
 107
 108 template <class T> inline void GRefPtr<T>::swap(GRefPtr<T>& o)
 109 {
 110     std::swap(m_ptr, o.m_ptr);
 111 }
 112
 113 template <class T> inline void swap(GRefPtr<T>& a, GRefPtr<T>& b)
 114 {
 115     a.swap(b);
 116 }
 117
 118 template <typename T, typename U> inline bool operator==(const GRefPtr<T>& a, const GRefPtr<U>& b)
 119 {
 120     return a.get() == b.get();
 121 }
 122
 123 template <typename T, typename U> inline bool operator==(const GRefPtr<T>& a, U* b)
 124 {
 125     return a.get() == b;
 126 }
 127
 128 template <typename T, typename U> inline bool operator==(T* a, const GRefPtr<U>& b)
 129 {
 130     return a == b.get();
 131 }
 132
 133 template <typename T, typename U> inline bool operator!=(const GRefPtr<T>& a, const GRefPtr<U>& b)
 134 {
 135     return a.get() != b.get();
 136 }
 137
 138 template <typename T, typename U> inline bool operator!=(const GRefPtr<T>& a, U* b)
 139 {
 140     return a.get() != b;
 141 }
 142
 143 template <typename T, typename U> inline bool operator!=(T* a, const GRefPtr<U>& b)
 144 {
 145     return a != b.get();
 146 }
 147
 148 template <typename T, typename U> inline GRefPtr<T> static_pointer_cast(const GRefPtr<U>& p)
 149 {
 150     return GRefPtr<T>(static_cast<T*>(p.get()));
 151 }
 152
 153 template <typename T, typename U> inline GRefPtr<T> const_pointer_cast(const GRefPtr<U>& p)
 154 {
 155     return GRefPtr<T>(const_cast<T*>(p.get()));
 156 }
 157
 158 template <typename T> inline T* getPtr(const GRefPtr<T>& p)
 159 {
 160     return p.get();
 161 }
 162
 163 template <typename T> GRefPtr<T> adoptGRef(T* p)
 164 {
 165     return GRefPtr<T>(p, GRefPtrAdopt);
 166 }
 167
 168 template <typename T> inline T* refGPtr(T* ptr)
 169 {
 170     if (ptr)
 171         g_object_ref_sink(ptr);
 172     return ptr;
 173 }
 174
 175 template <typename T> inline void derefGPtr(T* ptr)
 176 {
 177     if (ptr)
 178         g_object_unref(ptr);
 179 }
 180
 181 } // namespace WTF
 182
 183 using WTF::GRefPtr;
 184 using WTF::refGPtr;
 185 using WTF::derefGPtr;
 186 using WTF::adoptGRef;
 187 using WTF::static_pointer_cast;
 188 using WTF::const_pointer_cast;
 189
 190 #endif // WTF_GRefPtr_h