wtf/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 <glib.h>
  27 #include <wtf/Assertions.h>
  28 #include <wtf/Noncopyable.h>
  29
  30 namespace WTF {
  31     template <typename T> inline void freeOwnedGPtr(T* ptr) { g_free(reinterpret_cast<void*>(ptr)); }
  32     template<> void freeOwnedGPtr<GError>(GError*);
  33     template<> void freeOwnedGPtr<GList>(GList*);
  34     template<> void freeOwnedGPtr<GCond>(GCond*);
  35     template<> void freeOwnedGPtr<GMutex>(GMutex*);
  36     template<> void freeOwnedGPtr<GPatternSpec>(GPatternSpec*);
  37     template<> void freeOwnedGPtr<GDir>(GDir*);
  38
  39     template <typename T> class GOwnPtr : Noncopyable {
  40     public:
  41         explicit GOwnPtr(T* ptr = 0) : m_ptr(ptr) { }
  42         ~GOwnPtr() { freeOwnedGPtr(m_ptr); }
  43
  44         T* get() const { return m_ptr; }
  45         T* release() { T* ptr = m_ptr; m_ptr = 0; return ptr; }
  46         T*& outPtr() { ASSERT(!m_ptr); return m_ptr; }
  47
  48         void set(T* ptr) { ASSERT(!ptr || m_ptr != ptr); freeOwnedGPtr(m_ptr); m_ptr = ptr; }
  49         void clear() { freeOwnedGPtr(m_ptr); m_ptr = 0; }
  50
  51         T& operator*() const { ASSERT(m_ptr); return *m_ptr; }
  52         T* operator->() const { ASSERT(m_ptr); return m_ptr; }
  53
  54         bool operator!() const { return !m_ptr; }
  55
  56         // This conversion operator allows implicit conversion to bool but not to other integer types.
  57         typedef T* GOwnPtr::*UnspecifiedBoolType;
  58         operator UnspecifiedBoolType() const { return m_ptr ? &GOwnPtr::m_ptr : 0; }
  59
  60         void swap(GOwnPtr& o) { std::swap(m_ptr, o.m_ptr); }
  61
  62     private:
  63         T* m_ptr;
  64     };
  65
  66     template <typename T> inline void swap(GOwnPtr<T>& a, GOwnPtr<T>& b) { a.swap(b); }
  67
  68     template <typename T, typename U> inline bool operator==(const GOwnPtr<T>& a, U* b)
  69     {
  70         return a.get() == b;
  71     }
  72
  73     template <typename T, typename U> inline bool operator==(T* a, const GOwnPtr<U>& b)
  74     {
  75         return a == b.get();
  76     }
  77
  78     template <typename T, typename U> inline bool operator!=(const GOwnPtr<T>& a, U* b)
  79     {
  80         return a.get() != b;
  81     }
  82
  83     template <typename T, typename U> inline bool operator!=(T* a, const GOwnPtr<U>& b)
  84     {
  85         return a != b.get();
  86     }
  87
  88     template <typename T> inline typename GOwnPtr<T>::PtrType getPtr(const GOwnPtr<T>& p)
  89     {
  90         return p.get();
  91     }
  92
  93 } // namespace WTF
  94
  95 using WTF::GOwnPtr;
  96
  97 #endif // GOwnPtr_h