boost/boost/exception/enable_error_info.hpp

   1 //Copyright (c) 2006-2008 Emil Dotchevski and Reverge Studios, Inc.
   2
   3 //Distributed under the Boost Software License, Version 1.0. (See accompanying
   4 //file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   5
   6 #ifndef UUID_0C5D492E909711DCB658AD4556D89593
   7 #define UUID_0C5D492E909711DCB658AD4556D89593
   8
   9 #include <boost/exception/exception.hpp>
  10 #include <boost/detail/workaround.hpp>
  11 #include <boost/config.hpp>
  12 #include <stddef.h>
  13
  14 namespace
  15 boost
  16     {
  17     namespace
  18     exception_detail
  19         {
  20         template <class T>
  21         struct
  22         error_info_injector:
  23             public T,
  24             public exception
  25             {
  26             explicit
  27             error_info_injector( T const & x ):
  28                 T(x)
  29                 {
  30                 }
  31
  32             ~error_info_injector() throw()
  33                 {
  34                 }
  35
  36             char const *
  37             diagnostic_information() const throw()
  38                 {
  39                 return boost::exception::_diagnostic_information(T::what());
  40                 }
  41             };
  42
  43         struct large_size { char c[256]; };
  44         large_size dispatch( exception * );
  45
  46         struct small_size { };
  47         small_size dispatch( void * );
  48
  49         template <class,size_t>
  50         struct enable_error_info_helper;
  51
  52         template <class T>
  53         struct
  54         enable_error_info_helper<T,sizeof(large_size)>
  55             {
  56             typedef T type;
  57             };
  58
  59         template <class T>
  60         struct
  61         enable_error_info_helper<T,sizeof(small_size)>
  62             {
  63             typedef error_info_injector<T> type;
  64             };
  65
  66 #if BOOST_WORKAROUND(__BORLANDC__,BOOST_TESTED_AT(0x582))
  67         template <class T>
  68         struct
  69         sizeof_dispatch
  70             {
  71             BOOST_STATIC_CONSTANT(int, value = sizeof(dispatch((T*)0)) );
  72             };
  73
  74         template <class T>
  75         struct
  76         enable_error_info_return_type
  77             {
  78             typedef typename enable_error_info_helper<T,sizeof_dispatch<T>::value>::type type;
  79             };
  80 #else
  81         template <class T>
  82         struct
  83         enable_error_info_return_type
  84             {
  85             typedef typename enable_error_info_helper<T,sizeof(dispatch((T*)0))>::type type;
  86             };
  87 #endif
  88         }
  89
  90     template <class T>
  91     inline
  92 #if !BOOST_WORKAROUND(__BORLANDC__,BOOST_TESTED_AT(0x582))
  93     typename
  94 #endif
  95     exception_detail::enable_error_info_return_type<T>::type
  96     enable_error_info( T const & x )
  97         {
  98         return
  99 #if !BOOST_WORKAROUND(__BORLANDC__,BOOST_TESTED_AT(0x582))
 100         typename
 101 #endif
 102         exception_detail::enable_error_info_return_type<T>::type(x);
 103         }
 104     }
 105
 106 #endif