wtf/gtk/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 #include <algorithm>
  26 #include <wtf/Assertions.h>
  27 #include <wtf/Noncopyable.h>
  28
  29 // Forward delcarations at this point avoid the need to include GLib includes
  30 // in WTF headers.
  31 typedef struct _GError GError;
  32 typedef struct _GList GList;
  33 typedef struct _GCond GCond;
  34 typedef struct _GMutex GMutex;
  35 typedef struct _GPatternSpec GPatternSpec;
  36 typedef struct _GDir GDir;
  37 typedef struct _GHashTable GHashTable;
  38 extern "C" void g_free(void*);
  39
  40 namespace WTF {
  41
  42 template <typename T> inline void freeOwnedGPtr(T* ptr);
  43 template<> void freeOwnedGPtr<GError>(GError*);
  44 template<> void freeOwnedGPtr<GList>(GList*);
  45 template<> void freeOwnedGPtr<GCond>(GCond*);
  46 template<> void freeOwnedGPtr<GMutex>(GMutex*);
  47 template<> void freeOwnedGPtr<GPatternSpec>(GPatternSpec*);
  48 template<> void freeOwnedGPtr<GDir>(GDir*);
  49 template<> void freeOwnedGPtr<GHashTable>(GHashTable*);
  50
  51 template <typename T> class GOwnPtr : public Noncopyable {
  52 public:
  53     explicit GOwnPtr(T* ptr = 0) : m_ptr(ptr) { }
  54     ~GOwnPtr() { freeOwnedGPtr(m_ptr); }
  55
  56     T* get() const { return m_ptr; }
  57     T* release()
  58     {
  59         T* ptr = m_ptr;
  60         m_ptr = 0;
  61         return ptr;
  62     }
  63
  64     T*& outPtr()
  65     {
  66         ASSERT(!m_ptr);
  67         return m_ptr;
  68     }
  69
  70     void set(T* ptr)
  71     {
  72         ASSERT(!ptr || m_ptr != ptr);
  73         freeOwnedGPtr(m_ptr);
  74         m_ptr = ptr;
  75     }
  76
  77     void clear()
  78     {
  79         freeOwnedGPtr(m_ptr);
  80         m_ptr = 0;
  81     }
  82
  83     T& operator*() const
  84     {
  85         ASSERT(m_ptr);
  86         return *m_ptr;
  87     }
  88
  89     T* operator->() const
  90     {
  91         ASSERT(m_ptr);
  92         return m_ptr;
  93     }
  94
  95     bool operator!() const { return !m_ptr; }
  96
  97     // This conversion operator allows implicit conversion to bool but not to other integer types.
  98     typedef T* GOwnPtr::*UnspecifiedBoolType;
  99     operator UnspecifiedBoolType() const { return m_ptr ? &GOwnPtr::m_ptr : 0; }
 100
 101     void swap(GOwnPtr& o) { std::swap(m_ptr, o.m_ptr); }
 102
 103 private:
 104     T* m_ptr;
 105 };
 106
 107 template <typename T> inline void swap(GOwnPtr<T>& a, GOwnPtr<T>& b)
 108 {
 109     a.swap(b);
 110 }
 111
 112 template <typename T, typename U> inline bool operator==(const GOwnPtr<T>& a, U* b)
 113 {
 114     return a.get() == b;
 115 }
 116
 117 template <typename T, typename U> inline bool operator==(T* a, const GOwnPtr<U>& b)
 118 {
 119     return a == b.get();
 120 }
 121
 122 template <typename T, typename U> inline bool operator!=(const GOwnPtr<T>& a, U* b)
 123 {
 124     return a.get() != b;
 125 }
 126
 127 template <typename T, typename U> inline bool operator!=(T* a, const GOwnPtr<U>& b)
 128 {
 129     return a != b.get();
 130 }
 131
 132 template <typename T> inline typename GOwnPtr<T>::PtrType getPtr(const GOwnPtr<T>& p)
 133 {
 134     return p.get();
 135 }
 136
 137 template <typename T> inline void freeOwnedGPtr(T* ptr)
 138 {
 139     g_free(ptr);
 140 }
 141
 142 } // namespace WTF
 143
 144 using WTF::GOwnPtr;
 145
 146 #endif // GOwnPtr_h