ceph/src/boost/boost/smart_ptr/detail/sp_counted_base_w32.hpp

   1 #ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_W32_HPP_INCLUDED
   2 #define BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_W32_HPP_INCLUDED
   3
   4 // MS compatible compilers support #pragma once
   5
   6 #if defined(_MSC_VER) && (_MSC_VER >= 1020)
   7 # pragma once
   8 #endif
   9
  10 //
  11 //  detail/sp_counted_base_w32.hpp
  12 //
  13 //  Copyright (c) 2001, 2002, 2003 Peter Dimov and Multi Media Ltd.
  14 //  Copyright 2004-2005 Peter Dimov
  15 //
  16 //  Distributed under the Boost Software License, Version 1.0. (See
  17 //  accompanying file LICENSE_1_0.txt or copy at
  18 //  http://www.boost.org/LICENSE_1_0.txt)
  19 //
  20 //
  21 //  Lock-free algorithm by Alexander Terekhov
  22 //
  23 //  Thanks to Ben Hitchings for the #weak + (#shared != 0)
  24 //  formulation
  25 //
  26
  27 #include <boost/smart_ptr/detail/sp_interlocked.hpp>
  28 #include <boost/detail/workaround.hpp>
  29 #include <boost/detail/sp_typeinfo.hpp>
  30
  31 namespace boost
  32 {
  33
  34 namespace detail
  35 {
  36
  37 class sp_counted_base
  38 {
  39 private:
  40
  41     sp_counted_base( sp_counted_base const & );
  42     sp_counted_base & operator= ( sp_counted_base const & );
  43
  44     long use_count_;        // #shared
  45     long weak_count_;       // #weak + (#shared != 0)
  46
  47 public:
  48
  49     sp_counted_base(): use_count_( 1 ), weak_count_( 1 )
  50     {
  51     }
  52
  53     virtual ~sp_counted_base() // nothrow
  54     {
  55     }
  56
  57     // dispose() is called when use_count_ drops to zero, to release
  58     // the resources managed by *this.
  59
  60     virtual void dispose() = 0; // nothrow
  61
  62     // destroy() is called when weak_count_ drops to zero.
  63
  64     virtual void destroy() // nothrow
  65     {
  66         delete this;
  67     }
  68
  69     virtual void * get_deleter( sp_typeinfo const & ti ) = 0;
  70     virtual void * get_local_deleter( sp_typeinfo const & ti ) = 0;
  71     virtual void * get_untyped_deleter() = 0;
  72
  73     void add_ref_copy()
  74     {
  75         BOOST_SP_INTERLOCKED_INCREMENT( &use_count_ );
  76     }
  77
  78     bool add_ref_lock() // true on success
  79     {
  80         for( ;; )
  81         {
  82             long tmp = static_cast< long const volatile& >( use_count_ );
  83             if( tmp == 0 ) return false;
  84
  85 #if defined( BOOST_MSVC ) && BOOST_WORKAROUND( BOOST_MSVC, == 1200 )
  86
  87             // work around a code generation bug
  88
  89             long tmp2 = tmp + 1;
  90             if( BOOST_SP_INTERLOCKED_COMPARE_EXCHANGE( &use_count_, tmp2, tmp ) == tmp2 - 1 ) return true;
  91
  92 #else
  93
  94             if( BOOST_SP_INTERLOCKED_COMPARE_EXCHANGE( &use_count_, tmp + 1, tmp ) == tmp ) return true;
  95
  96 #endif
  97         }
  98     }
  99
 100     void release() // nothrow
 101     {
 102         if( BOOST_SP_INTERLOCKED_DECREMENT( &use_count_ ) == 0 )
 103         {
 104             dispose();
 105             weak_release();
 106         }
 107     }
 108
 109     void weak_add_ref() // nothrow
 110     {
 111         BOOST_SP_INTERLOCKED_INCREMENT( &weak_count_ );
 112     }
 113
 114     void weak_release() // nothrow
 115     {
 116         if( BOOST_SP_INTERLOCKED_DECREMENT( &weak_count_ ) == 0 )
 117         {
 118             destroy();
 119         }
 120     }
 121
 122     long use_count() const // nothrow
 123     {
 124         return static_cast<long const volatile &>( use_count_ );
 125     }
 126 };
 127
 128 } // namespace detail
 129
 130 } // namespace boost
 131
 132 #endif  // #ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_W32_HPP_INCLUDED