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/smart_ptr/detail/sp_typeinfo_.hpp>
  29 #include <boost/detail/workaround.hpp>
  30 #include <boost/config.hpp>
  31
  32 namespace boost
  33 {
  34
  35 namespace detail
  36 {
  37
  38 class BOOST_SYMBOL_VISIBLE sp_counted_base
  39 {
  40 private:
  41
  42     sp_counted_base( sp_counted_base const & );
  43     sp_counted_base & operator= ( sp_counted_base const & );
  44
  45     long use_count_;        // #shared
  46     long weak_count_;       // #weak + (#shared != 0)
  47
  48 public:
  49
  50     sp_counted_base(): use_count_( 1 ), weak_count_( 1 )
  51     {
  52     }
  53
  54     virtual ~sp_counted_base() // nothrow
  55     {
  56     }
  57
  58     // dispose() is called when use_count_ drops to zero, to release
  59     // the resources managed by *this.
  60
  61     virtual void dispose() = 0; // nothrow
  62
  63     // destroy() is called when weak_count_ drops to zero.
  64
  65     virtual void destroy() // nothrow
  66     {
  67         delete this;
  68     }
  69
  70     virtual void * get_deleter( sp_typeinfo_ const & ti ) = 0;
  71     virtual void * get_local_deleter( sp_typeinfo_ const & ti ) = 0;
  72     virtual void * get_untyped_deleter() = 0;
  73
  74     void add_ref_copy()
  75     {
  76         BOOST_SP_INTERLOCKED_INCREMENT( &use_count_ );
  77     }
  78
  79     bool add_ref_lock() // true on success
  80     {
  81         for( ;; )
  82         {
  83             long tmp = static_cast< long const volatile& >( use_count_ );
  84             if( tmp == 0 ) return false;
  85
  86 #if defined( BOOST_MSVC ) && BOOST_WORKAROUND( BOOST_MSVC, == 1200 )
  87
  88             // work around a code generation bug
  89
  90             long tmp2 = tmp + 1;
  91             if( BOOST_SP_INTERLOCKED_COMPARE_EXCHANGE( &use_count_, tmp2, tmp ) == tmp2 - 1 ) return true;
  92
  93 #else
  94
  95             if( BOOST_SP_INTERLOCKED_COMPARE_EXCHANGE( &use_count_, tmp + 1, tmp ) == tmp ) return true;
  96
  97 #endif
  98         }
  99     }
 100
 101     void release() // nothrow
 102     {
 103         if( BOOST_SP_INTERLOCKED_DECREMENT( &use_count_ ) == 0 )
 104         {
 105             dispose();
 106             weak_release();
 107         }
 108     }
 109
 110     void weak_add_ref() // nothrow
 111     {
 112         BOOST_SP_INTERLOCKED_INCREMENT( &weak_count_ );
 113     }
 114
 115     void weak_release() // nothrow
 116     {
 117         if( BOOST_SP_INTERLOCKED_DECREMENT( &weak_count_ ) == 0 )
 118         {
 119             destroy();
 120         }
 121     }
 122
 123     long use_count() const // nothrow
 124     {
 125         return static_cast<long const volatile &>( use_count_ );
 126     }
 127 };
 128
 129 } // namespace detail
 130
 131 } // namespace boost
 132
 133 #endif  // #ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_W32_HPP_INCLUDED