wtf/gtk/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
  31 namespace WTF {
  32
  33 enum GRefPtrAdoptType { GRefPtrAdopt };
  34 template <typename T> inline T* refGPtr(T*);
  35 template <typename T> inline void derefGPtr(T*);
  36 template <typename T> class GRefPtr;
  37 template <typename T> GRefPtr<T> adoptGRef(T*);
  38 template <> GHashTable* refGPtr(GHashTable* ptr);
  39 template <> void derefGPtr(GHashTable* ptr);
  40
  41 template <typename T> class GRefPtr {
  42 public:
  43     GRefPtr() : m_ptr(0) { }
  44     GRefPtr(T* ptr) : m_ptr(ptr) { if (ptr) refGPtr(ptr); }
  45     GRefPtr(const GRefPtr& o) : m_ptr(o.m_ptr) { if (T* ptr = m_ptr) refGPtr(ptr); }
  46     template <typename U> GRefPtr(const GRefPtr<U>& o) : m_ptr(o.get()) { if (T* ptr = m_ptr) refGPtr(ptr); }
  47
  48     ~GRefPtr() { if (T* ptr = m_ptr) derefGPtr(ptr); }
  49
  50     void clear()
  51     {
  52         if (T* ptr = m_ptr)
  53             derefGPtr(ptr);
  54         m_ptr = 0;
  55     }
  56
  57     T* get() const { return m_ptr; }
  58     T& operator*() const { return *m_ptr; }
  59     ALWAYS_INLINE T* operator->() const { return m_ptr; }
  60
  61     bool operator!() const { return !m_ptr; }
  62
  63     // This conversion operator allows implicit conversion to bool but not to other integer types.
  64     typedef T* GRefPtr::*UnspecifiedBoolType;
  65     operator UnspecifiedBoolType() const { return m_ptr ? &GRefPtr::m_ptr : 0; }
  66
  67     GRefPtr& operator=(const GRefPtr&);
  68     GRefPtr& operator=(T*);
  69     template <typename U> GRefPtr& operator=(const GRefPtr<U>&);
  70
  71     void swap(GRefPtr&);
  72     friend GRefPtr adoptGRef<T>(T*);
  73
  74 private:
  75     static T* hashTableDeletedValue() { return reinterpret_cast<T*>(-1); }
  76     // Adopting constructor.
  77     GRefPtr(T* ptr, GRefPtrAdoptType) : m_ptr(ptr) {}
  78
  79     T* m_ptr;
  80 };
  81
  82 template <typename T> inline GRefPtr<T>& GRefPtr<T>::operator=(const GRefPtr<T>& o)
  83 {
  84     T* optr = o.get();
  85     if (optr)
  86         refGPtr(optr);
  87     T* ptr = m_ptr;
  88     m_ptr = optr;
  89     if (ptr)
  90         derefGPtr(ptr);
  91     return *this;
  92 }
  93
  94 template <typename T> inline GRefPtr<T>& GRefPtr<T>::operator=(T* optr)
  95 {
  96     T* ptr = m_ptr;
  97     if (optr)
  98         refGPtr(optr);
  99     m_ptr = optr;
 100     if (ptr)
 101         derefGPtr(ptr);
 102     return *this;
 103 }
 104
 105 template <class T> inline void GRefPtr<T>::swap(GRefPtr<T>& o)
 106 {
 107     std::swap(m_ptr, o.m_ptr);
 108 }
 109
 110 template <class T> inline void swap(GRefPtr<T>& a, GRefPtr<T>& b)
 111 {
 112     a.swap(b);
 113 }
 114
 115 template <typename T, typename U> inline bool operator==(const GRefPtr<T>& a, const GRefPtr<U>& b)
 116 {
 117     return a.get() == b.get();
 118 }
 119
 120 template <typename T, typename U> inline bool operator==(const GRefPtr<T>& a, U* b)
 121 {
 122     return a.get() == b;
 123 }
 124
 125 template <typename T, typename U> inline bool operator==(T* a, const GRefPtr<U>& b)
 126 {
 127     return a == b.get();
 128 }
 129
 130 template <typename T, typename U> inline bool operator!=(const GRefPtr<T>& a, const GRefPtr<U>& b)
 131 {
 132     return a.get() != b.get();
 133 }
 134
 135 template <typename T, typename U> inline bool operator!=(const GRefPtr<T>& a, U* b)
 136 {
 137     return a.get() != b;
 138 }
 139
 140 template <typename T, typename U> inline bool operator!=(T* a, const GRefPtr<U>& b)
 141 {
 142     return a != b.get();
 143 }
 144
 145 template <typename T, typename U> inline GRefPtr<T> static_pointer_cast(const GRefPtr<U>& p)
 146 {
 147     return GRefPtr<T>(static_cast<T*>(p.get()));
 148 }
 149
 150 template <typename T, typename U> inline GRefPtr<T> const_pointer_cast(const GRefPtr<U>& p)
 151 {
 152     return GRefPtr<T>(const_cast<T*>(p.get()));
 153 }
 154
 155 template <typename T> inline T* getPtr(const GRefPtr<T>& p)
 156 {
 157     return p.get();
 158 }
 159
 160 template <typename T> GRefPtr<T> adoptGRef(T* p)
 161 {
 162     return GRefPtr<T>(p, GRefPtrAdopt);
 163 }
 164
 165 template <typename T> inline T* refGPtr(T* ptr)
 166 {
 167     if (ptr)
 168         g_object_ref_sink(ptr);
 169     return ptr;
 170 }
 171
 172 template <typename T> inline void derefGPtr(T* ptr)
 173 {
 174     if (ptr)
 175         g_object_unref(ptr);
 176 }
 177
 178 } // namespace WTF
 179
 180 using WTF::GRefPtr;
 181 using WTF::refGPtr;
 182 using WTF::derefGPtr;
 183 using WTF::adoptGRef;
 184 using WTF::static_pointer_cast;
 185 using WTF::const_pointer_cast;
 186
 187 #endif // WTF_GRefPtr_h