3rdparty/boost/boost/smart_ptr/detail/sp_counted_base_clang.hpp

   1 #ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_CLANG_HPP_INCLUDED
   2 #define BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_CLANG_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 //  detail/sp_counted_base_clang.hpp - __c11 clang intrinsics
  11 //
  12 //  Copyright (c) 2007, 2013, 2015 Peter Dimov
  13 //
  14 //  Distributed under the Boost Software License, Version 1.0.
  15 //  See accompanying file LICENSE_1_0.txt or copy at
  16 //  http://www.boost.org/LICENSE_1_0.txt
  17
  18 #include <boost/smart_ptr/detail/sp_typeinfo_.hpp>
  19 #include <boost/smart_ptr/detail/sp_noexcept.hpp>
  20 #include <boost/config.hpp>
  21 #include <boost/cstdint.hpp>
  22
  23 namespace boost
  24 {
  25
  26 namespace detail
  27 {
  28
  29 typedef _Atomic( boost::int_least32_t ) atomic_int_least32_t;
  30
  31 inline void atomic_increment( atomic_int_least32_t * pw ) BOOST_SP_NOEXCEPT
  32 {
  33     __c11_atomic_fetch_add( pw, 1, __ATOMIC_RELAXED );
  34 }
  35
  36 inline boost::int_least32_t atomic_decrement( atomic_int_least32_t * pw ) BOOST_SP_NOEXCEPT
  37 {
  38     return __c11_atomic_fetch_sub( pw, 1, __ATOMIC_ACQ_REL );
  39 }
  40
  41 inline boost::int_least32_t atomic_conditional_increment( atomic_int_least32_t * pw ) BOOST_SP_NOEXCEPT
  42 {
  43     // long r = *pw;
  44     // if( r != 0 ) ++*pw;
  45     // return r;
  46
  47     boost::int_least32_t r = __c11_atomic_load( pw, __ATOMIC_RELAXED );
  48
  49     for( ;; )
  50     {
  51         if( r == 0 )
  52         {
  53             return r;
  54         }
  55
  56         if( __c11_atomic_compare_exchange_weak( pw, &r, r + 1, __ATOMIC_RELAXED, __ATOMIC_RELAXED ) )
  57         {
  58             return r;
  59         }
  60     }
  61 }
  62
  63 #if defined(__clang__)
  64 # pragma clang diagnostic push
  65 # pragma clang diagnostic ignored "-Wweak-vtables"
  66 #endif
  67
  68 class BOOST_SYMBOL_VISIBLE sp_counted_base
  69 {
  70 private:
  71
  72     sp_counted_base( sp_counted_base const & );
  73     sp_counted_base & operator= ( sp_counted_base const & );
  74
  75     atomic_int_least32_t use_count_;    // #shared
  76     atomic_int_least32_t weak_count_;   // #weak + (#shared != 0)
  77
  78 public:
  79
  80     sp_counted_base() BOOST_SP_NOEXCEPT
  81     {
  82         __c11_atomic_init( &use_count_, 1 );
  83         __c11_atomic_init( &weak_count_, 1 );
  84     }
  85
  86     virtual ~sp_counted_base() /*BOOST_SP_NOEXCEPT*/
  87     {
  88     }
  89
  90     // dispose() is called when use_count_ drops to zero, to release
  91     // the resources managed by *this.
  92
  93     virtual void dispose() BOOST_SP_NOEXCEPT = 0; // nothrow
  94
  95     // destroy() is called when weak_count_ drops to zero.
  96
  97     virtual void destroy() BOOST_SP_NOEXCEPT // nothrow
  98     {
  99         delete this;
 100     }
 101
 102     virtual void * get_deleter( sp_typeinfo_ const & ti ) BOOST_SP_NOEXCEPT = 0;
 103     virtual void * get_local_deleter( sp_typeinfo_ const & ti ) BOOST_SP_NOEXCEPT = 0;
 104     virtual void * get_untyped_deleter() BOOST_SP_NOEXCEPT = 0;
 105
 106     void add_ref_copy() BOOST_SP_NOEXCEPT
 107     {
 108         atomic_increment( &use_count_ );
 109     }
 110
 111     bool add_ref_lock() BOOST_SP_NOEXCEPT // true on success
 112     {
 113         return atomic_conditional_increment( &use_count_ ) != 0;
 114     }
 115
 116     void release() BOOST_SP_NOEXCEPT
 117     {
 118         if( atomic_decrement( &use_count_ ) == 1 )
 119         {
 120             dispose();
 121             weak_release();
 122         }
 123     }
 124
 125     void weak_add_ref() BOOST_SP_NOEXCEPT
 126     {
 127         atomic_increment( &weak_count_ );
 128     }
 129
 130     void weak_release() BOOST_SP_NOEXCEPT
 131     {
 132         if( atomic_decrement( &weak_count_ ) == 1 )
 133         {
 134             destroy();
 135         }
 136     }
 137
 138     long use_count() const BOOST_SP_NOEXCEPT
 139     {
 140         return __c11_atomic_load( const_cast< atomic_int_least32_t* >( &use_count_ ), __ATOMIC_ACQUIRE );
 141     }
 142 };
 143
 144 #if defined(__clang__)
 145 # pragma clang diagnostic pop
 146 #endif
 147
 148 } // namespace detail
 149
 150 } // namespace boost
 151
 152 #endif  // #ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_CLANG_HPP_INCLUDED