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      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
    147