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      1 /*
      2  *  Copyright (C) 2006, 2007 Apple Inc. All rights reserved.
      3  *  Copyright (C) 2008 Collabora Ltd.
      4  *  Copyright (C) 2010 Company 100, Inc.
      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 OwnPtrBrew_h
     24 #define OwnPtrBrew_h
     25 
     26 #include <algorithm>
     27 #include <wtf/Assertions.h>
     28 #include <wtf/Noncopyable.h>
     29 
     30 // Forward delcarations at this point avoid the need to include BREW includes
     31 // in WTF headers.
     32 typedef struct _IFileMgr IFileMgr;
     33 typedef struct _IFile IFile;
     34 typedef struct IBitmap IBitmap;
     35 
     36 namespace WTF {
     37 
     38 template <typename T> void freeOwnedPtrBrew(T* ptr);
     39 template<> void freeOwnedPtrBrew<IFileMgr>(IFileMgr*);
     40 template<> void freeOwnedPtrBrew<IFile>(IFile*);
     41 template<> void freeOwnedPtrBrew<IBitmap>(IBitmap*);
     42 
     43 template <typename T> class OwnPtrBrew : public Noncopyable {
     44 public:
     45     explicit OwnPtrBrew(T* ptr = 0) : m_ptr(ptr) { }
     46     ~OwnPtrBrew() { freeOwnedPtrBrew(m_ptr); }
     47 
     48     T* get() const { return m_ptr; }
     49     T* release()
     50     {
     51         T* ptr = m_ptr;
     52         m_ptr = 0;
     53         return ptr;
     54     }
     55 
     56     T*& outPtr()
     57     {
     58         ASSERT(!m_ptr);
     59         return m_ptr;
     60     }
     61 
     62     void set(T* ptr)
     63     {
     64         ASSERT(!ptr || m_ptr != ptr);
     65         freeOwnedPtrBrew(m_ptr);
     66         m_ptr = ptr;
     67     }
     68 
     69     void clear()
     70     {
     71         freeOwnedPtrBrew(m_ptr);
     72         m_ptr = 0;
     73     }
     74 
     75     T& operator*() const
     76     {
     77         ASSERT(m_ptr);
     78         return *m_ptr;
     79     }
     80 
     81     T* operator->() const
     82     {
     83         ASSERT(m_ptr);
     84         return m_ptr;
     85     }
     86 
     87     bool operator!() const { return !m_ptr; }
     88 
     89     // This conversion operator allows implicit conversion to bool but not to other integer types.
     90     typedef T* OwnPtrBrew::*UnspecifiedBoolType;
     91     operator UnspecifiedBoolType() const { return m_ptr ? &OwnPtrBrew::m_ptr : 0; }
     92 
     93     void swap(OwnPtrBrew& o) { std::swap(m_ptr, o.m_ptr); }
     94 
     95 private:
     96     T* m_ptr;
     97 };
     98 
     99 template <typename T> inline void swap(OwnPtrBrew<T>& a, OwnPtrBrew<T>& b)
    100 {
    101     a.swap(b);
    102 }
    103 
    104 template <typename T, typename U> inline bool operator==(const OwnPtrBrew<T>& a, U* b)
    105 {
    106     return a.get() == b;
    107 }
    108 
    109 template <typename T, typename U> inline bool operator==(T* a, const OwnPtrBrew<U>& b)
    110 {
    111     return a == b.get();
    112 }
    113 
    114 template <typename T, typename U> inline bool operator!=(const OwnPtrBrew<T>& a, U* b)
    115 {
    116     return a.get() != b;
    117 }
    118 
    119 template <typename T, typename U> inline bool operator!=(T* a, const OwnPtrBrew<U>& b)
    120 {
    121     return a != b.get();
    122 }
    123 
    124 template <typename T> inline typename OwnPtrBrew<T>::PtrType getPtr(const OwnPtrBrew<T>& p)
    125 {
    126     return p.get();
    127 }
    128 
    129 } // namespace WTF
    130 
    131 using WTF::OwnPtrBrew;
    132 
    133 #endif // OwnPtrBrew_h
    134