wtf/gobject/GOwnPtr.h

   1 /*
   2  *  Copyright (C) 2006, 2007 Apple Inc. All rights reserved.
   3  *  Copyright (C) 2008 Collabora Ltd.
   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 GOwnPtr_h
  23 #define GOwnPtr_h
  24
  25 #if ENABLE(GLIB_SUPPORT)
  26
  27 #include <algorithm>
  28 #include <wtf/Assertions.h>
  29 #include <wtf/Noncopyable.h>
  30
  31 extern "C" void g_free(void*);
  32
  33 namespace WTF {
  34
  35 template <typename T> inline void freeOwnedGPtr(T* ptr);
  36 template<> void freeOwnedGPtr<GError>(GError*);
  37 template<> void freeOwnedGPtr<GList>(GList*);
  38 template<> void freeOwnedGPtr<GCond>(GCond*);
  39 template<> void freeOwnedGPtr<GMutex>(GMutex*);
  40 template<> void freeOwnedGPtr<GPatternSpec>(GPatternSpec*);
  41 template<> void freeOwnedGPtr<GDir>(GDir*);
  42
  43 template <typename T> class GOwnPtr {
  44     WTF_MAKE_NONCOPYABLE(GOwnPtr);
  45 public:
  46     explicit GOwnPtr(T* ptr = 0) : m_ptr(ptr) { }
  47     ~GOwnPtr() { freeOwnedGPtr(m_ptr); }
  48
  49     T* get() const { return m_ptr; }
  50     T* release()
  51     {
  52         T* ptr = m_ptr;
  53         m_ptr = 0;
  54         return ptr;
  55     }
  56
  57     T*& outPtr()
  58     {
  59         ASSERT(!m_ptr);
  60         return m_ptr;
  61     }
  62
  63     void set(T* ptr)
  64     {
  65         ASSERT(!ptr || m_ptr != ptr);
  66         freeOwnedGPtr(m_ptr);
  67         m_ptr = ptr;
  68     }
  69
  70     void clear()
  71     {
  72         T* ptr = m_ptr;
  73         m_ptr = 0;
  74         freeOwnedGPtr(ptr);
  75     }
  76
  77     T& operator*() const
  78     {
  79         ASSERT(m_ptr);
  80         return *m_ptr;
  81     }
  82
  83     T* operator->() const
  84     {
  85         ASSERT(m_ptr);
  86         return m_ptr;
  87     }
  88
  89     bool operator!() const { return !m_ptr; }
  90
  91     // This conversion operator allows implicit conversion to bool but not to other integer types.
  92     typedef T* GOwnPtr::*UnspecifiedBoolType;
  93     operator UnspecifiedBoolType() const { return m_ptr ? &GOwnPtr::m_ptr : 0; }
  94
  95     void swap(GOwnPtr& o) { std::swap(m_ptr, o.m_ptr); }
  96
  97 private:
  98     T* m_ptr;
  99 };
 100
 101 template <typename T> inline void swap(GOwnPtr<T>& a, GOwnPtr<T>& b)
 102 {
 103     a.swap(b);
 104 }
 105
 106 template <typename T, typename U> inline bool operator==(const GOwnPtr<T>& a, U* b)
 107 {
 108     return a.get() == b;
 109 }
 110
 111 template <typename T, typename U> inline bool operator==(T* a, const GOwnPtr<U>& b)
 112 {
 113     return a == b.get();
 114 }
 115
 116 template <typename T, typename U> inline bool operator!=(const GOwnPtr<T>& a, U* b)
 117 {
 118     return a.get() != b;
 119 }
 120
 121 template <typename T, typename U> inline bool operator!=(T* a, const GOwnPtr<U>& b)
 122 {
 123     return a != b.get();
 124 }
 125
 126 template <typename T> inline typename GOwnPtr<T>::PtrType getPtr(const GOwnPtr<T>& p)
 127 {
 128     return p.get();
 129 }
 130
 131 template <typename T> inline void freeOwnedGPtr(T* ptr)
 132 {
 133     g_free(ptr);
 134 }
 135
 136 } // namespace WTF
 137
 138 using WTF::GOwnPtr;
 139
 140 #endif // ENABLE(GLIB_SUPPORT)
 141
 142 #endif // GOwnPtr_h
 143