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

   1 #ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_AIX_HPP_INCLUDED
   2 #define BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_AIX_HPP_INCLUDED
   3
   4 //
   5 //  detail/sp_counted_base_aix.hpp
   6 //   based on: detail/sp_counted_base_w32.hpp
   7 //
   8 //  Copyright (c) 2001, 2002, 2003 Peter Dimov and Multi Media Ltd.
   9 //  Copyright 2004-2005 Peter Dimov
  10 //  Copyright 2006 Michael van der Westhuizen
  11 //
  12 //  Distributed under the Boost Software License, Version 1.0. (See
  13 //  accompanying file LICENSE_1_0.txt or copy at
  14 //  http://www.boost.org/LICENSE_1_0.txt)
  15 //
  16 //
  17 //  Lock-free algorithm by Alexander Terekhov
  18 //
  19 //  Thanks to Ben Hitchings for the #weak + (#shared != 0)
  20 //  formulation
  21 //
  22
  23 #include <boost/smart_ptr/detail/sp_typeinfo_.hpp>
  24 #include <boost/config.hpp>
  25 #include <builtins.h>
  26 #include <sys/atomic_op.h>
  27
  28 namespace boost
  29 {
  30
  31 namespace detail
  32 {
  33
  34 inline void atomic_increment( int32_t* pw )
  35 {
  36     // ++*pw;
  37
  38     fetch_and_add( pw, 1 );
  39 }
  40
  41 inline int32_t atomic_decrement( int32_t * pw )
  42 {
  43     // return --*pw;
  44
  45     int32_t originalValue;
  46
  47     __lwsync();
  48     originalValue = fetch_and_add( pw, -1 );
  49     __isync();
  50
  51     return (originalValue - 1);
  52 }
  53
  54 inline int32_t atomic_conditional_increment( int32_t * pw )
  55 {
  56     // if( *pw != 0 ) ++*pw;
  57     // return *pw;
  58
  59     int32_t tmp = fetch_and_add( pw, 0 );
  60     for( ;; )
  61     {
  62         if( tmp == 0 ) return 0;
  63         if( compare_and_swap( pw, &tmp, tmp + 1 ) ) return (tmp + 1);
  64     }
  65 }
  66
  67 class BOOST_SYMBOL_VISIBLE sp_counted_base
  68 {
  69 private:
  70
  71     sp_counted_base( sp_counted_base const & );
  72     sp_counted_base & operator= ( sp_counted_base const & );
  73
  74     int32_t use_count_;        // #shared
  75     int32_t weak_count_;       // #weak + (#shared != 0)
  76
  77 public:
  78
  79     sp_counted_base(): use_count_( 1 ), weak_count_( 1 )
  80     {
  81     }
  82
  83     virtual ~sp_counted_base() // nothrow
  84     {
  85     }
  86
  87     // dispose() is called when use_count_ drops to zero, to release
  88     // the resources managed by *this.
  89
  90     virtual void dispose() = 0; // nothrow
  91
  92     // destroy() is called when weak_count_ drops to zero.
  93
  94     virtual void destroy() // nothrow
  95     {
  96         delete this;
  97     }
  98
  99     virtual void * get_deleter( sp_typeinfo_ const & ti ) = 0;
 100     virtual void * get_local_deleter( sp_typeinfo_ const & ti ) = 0;
 101     virtual void * get_untyped_deleter() = 0;
 102
 103     void add_ref_copy()
 104     {
 105         atomic_increment( &use_count_ );
 106     }
 107
 108     bool add_ref_lock() // true on success
 109     {
 110         return atomic_conditional_increment( &use_count_ ) != 0;
 111     }
 112
 113     void release() // nothrow
 114     {
 115         if( atomic_decrement( &use_count_ ) == 0 )
 116         {
 117             dispose();
 118             weak_release();
 119         }
 120     }
 121
 122     void weak_add_ref() // nothrow
 123     {
 124         atomic_increment( &weak_count_ );
 125     }
 126
 127     void weak_release() // nothrow
 128     {
 129         if( atomic_decrement( &weak_count_ ) == 0 )
 130         {
 131             destroy();
 132         }
 133     }
 134
 135     long use_count() const // nothrow
 136     {
 137         return fetch_and_add( const_cast<int32_t*>(&use_count_), 0 );
 138     }
 139 };
 140
 141 } // namespace detail
 142
 143 } // namespace boost
 144
 145 #endif  // #ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_AIX_HPP_INCLUDED