ceph/src/boost/libs/log/include/boost/log/detail/function_traits.hpp

   1 /*
   2  *          Copyright Andrey Semashev 2007 - 2015.
   3  * Distributed under the Boost Software License, Version 1.0.
   4  *    (See accompanying file LICENSE_1_0.txt or copy at
   5  *          http://www.boost.org/LICENSE_1_0.txt)
   6  */
   7 /*!
   8  * \file   function_traits.hpp
   9  * \author Andrey Semashev
  10  * \date   30.08.2009
  11  *
  12  * \brief  This header is the Boost.Log library implementation, see the library documentation
  13  *         at http://www.boost.org/doc/libs/release/libs/log/doc/html/index.html.
  14  */
  15
  16 #ifndef BOOST_LOG_DETAIL_FUNCTION_TRAITS_HPP_INCLUDED_
  17 #define BOOST_LOG_DETAIL_FUNCTION_TRAITS_HPP_INCLUDED_
  18
  19 #include <boost/mpl/has_xxx.hpp>
  20 #include <boost/log/detail/config.hpp>
  21
  22 #if defined(BOOST_NO_SFINAE) || defined(BOOST_MPL_CFG_NO_HAS_XXX)
  23 #   if !defined(BOOST_LOG_NO_FUNCTION_TRAITS)
  24 #      define BOOST_LOG_NO_FUNCTION_TRAITS
  25 #   endif
  26 #else
  27
  28 #include <boost/mpl/int.hpp>
  29 #include <boost/mpl/front.hpp>
  30 #include <boost/mpl/pop_front.hpp>
  31 #include <boost/type_traits/remove_cv.hpp>
  32 #include <boost/type_traits/remove_reference.hpp>
  33 #include <boost/function_types/function_arity.hpp>
  34 #include <boost/function_types/parameter_types.hpp>
  35 #include <boost/function_types/is_nonmember_callable_builtin.hpp>
  36 #include <boost/log/detail/header.hpp>
  37
  38 #ifdef BOOST_HAS_PRAGMA_ONCE
  39 #pragma once
  40 #endif
  41
  42 namespace boost {
  43
  44 BOOST_LOG_OPEN_NAMESPACE
  45
  46 namespace aux {
  47
  48     //  A number of traits to deal with functors
  49     BOOST_MPL_HAS_XXX_TRAIT_NAMED_DEF(has_argument_type, argument_type, false)
  50     BOOST_MPL_HAS_XXX_TRAIT_NAMED_DEF(has_first_argument_type, first_argument_type, false)
  51     BOOST_MPL_HAS_XXX_TRAIT_NAMED_DEF(has_second_argument_type, second_argument_type, false)
  52     BOOST_MPL_HAS_XXX_TRAIT_NAMED_DEF(has_arg1_type, arg1_type, false)
  53     BOOST_MPL_HAS_XXX_TRAIT_NAMED_DEF(has_arg2_type, arg2_type, false)
  54
  55     namespace has_arity_no_adl {
  56
  57         typedef char yes_type;
  58         struct no_type
  59         {
  60             char dummy[2];
  61         };
  62
  63         template< typename FunT, int ArityV = FunT::arity >
  64         struct checker
  65         {
  66         };
  67
  68         template< typename FunT >
  69         yes_type has_arity_impl(FunT const&, checker< FunT >*);
  70         template< typename FunT >
  71         no_type has_arity_impl(FunT const&, ...);
  72
  73     } // namespace has_arity_no_adl
  74
  75     //! The metafunction detects if the type has an arity static constant member
  76     template< typename FunT >
  77     struct has_arity
  78     {
  79         static FunT const& get_FunT();
  80
  81         enum value_t { value = (sizeof(has_arity_no_adl::has_arity_impl(get_FunT(), 0)) == sizeof(has_arity_no_adl::yes_type)) };
  82         typedef mpl::bool_< value > type;
  83     };
  84
  85     //! The metafunction results in an unqualified type with removed reference
  86     template< typename T >
  87     struct root_type :
  88         public remove_cv<
  89             typename remove_reference<
  90                 T
  91             >::type
  92         >
  93     {
  94     };
  95
  96     template<
  97         typename FunT,
  98         bool = function_types::is_nonmember_callable_builtin< FunT >::value,
  99         bool = has_argument_type< FunT >::value,
 100         bool = has_first_argument_type< FunT >::value,
 101         bool = has_arg1_type< FunT >::value
 102     >
 103     struct first_argument_type_of_impl
 104     {
 105     };
 106     template< typename FunT >
 107     struct first_argument_type_of_impl< FunT, true, false, false, false >
 108     {
 109         typedef typename root_type<
 110             typename mpl::front<
 111                 typename function_types::parameter_types< FunT >::type
 112             >::type
 113         >::type type;
 114     };
 115     template< typename FunT, bool HasFirstArgumentV, bool HasArg1V >
 116     struct first_argument_type_of_impl< FunT, false, true, HasFirstArgumentV, HasArg1V >
 117     {
 118         typedef typename root_type<
 119             typename FunT::argument_type
 120         >::type type;
 121     };
 122     template< typename FunT, bool HasArg1V >
 123     struct first_argument_type_of_impl< FunT, false, false, true, HasArg1V >
 124     {
 125         typedef typename root_type<
 126             typename FunT::first_argument_type
 127         >::type type;
 128     };
 129     template< typename FunT >
 130     struct first_argument_type_of_impl< FunT, false, false, false, true >
 131     {
 132         typedef typename root_type<
 133             typename FunT::arg1_type
 134         >::type type;
 135     };
 136
 137     //! The metafunction returns the first argument type of a function
 138     template< typename FunT >
 139     struct first_argument_type_of :
 140         public first_argument_type_of_impl< FunT >
 141     {
 142     };
 143
 144
 145     template<
 146         typename FunT,
 147         bool = function_types::is_nonmember_callable_builtin< FunT >::value,
 148         bool = has_second_argument_type< FunT >::value,
 149         bool = has_arg2_type< FunT >::value
 150     >
 151     struct second_argument_type_of_impl
 152     {
 153     };
 154     template< typename FunT >
 155     struct second_argument_type_of_impl< FunT, true, false, false >
 156     {
 157         typedef typename root_type<
 158             typename mpl::front<
 159                 typename mpl::pop_front<
 160                     typename function_types::parameter_types< FunT >::type
 161                 >::type
 162             >::type
 163         >::type type;
 164     };
 165     template< typename FunT, bool HasArg2V >
 166     struct second_argument_type_of_impl< FunT, false, true, HasArg2V >
 167     {
 168         typedef typename root_type<
 169             typename FunT::second_argument_type
 170         >::type type;
 171     };
 172     template< typename FunT >
 173     struct second_argument_type_of_impl< FunT, false, false, true >
 174     {
 175         typedef typename root_type<
 176             typename FunT::arg2_type
 177         >::type type;
 178     };
 179
 180     //! The metafunction returns the second argument type of a function
 181     template< typename FunT >
 182     struct second_argument_type_of :
 183         public second_argument_type_of_impl< FunT >
 184     {
 185     };
 186
 187
 188     template<
 189         typename FunT,
 190         bool = function_types::is_nonmember_callable_builtin< FunT >::value,
 191         bool = has_arity< FunT >::value,
 192         bool = has_argument_type< FunT >::value,
 193         bool = has_second_argument_type< FunT >::value
 194     >
 195     struct arity_of_impl
 196     {
 197     };
 198     template< typename FunT >
 199     struct arity_of_impl< FunT, true, false, false, false > :
 200         public function_types::function_arity< FunT >
 201     {
 202     };
 203     template< typename FunT, bool HasArgumentTypeV, bool HasSecondArgumentTypeV >
 204     struct arity_of_impl< FunT, false, true, HasArgumentTypeV, HasSecondArgumentTypeV > :
 205         public mpl::int_< FunT::arity >
 206     {
 207     };
 208     template< typename FunT, bool HasArgumentTypeV >
 209     struct arity_of_impl< FunT, false, false, HasArgumentTypeV, true > :
 210         public mpl::int_< 2 >
 211     {
 212     };
 213     template< typename FunT >
 214     struct arity_of_impl< FunT, false, false, true, false > :
 215         public mpl::int_< 1 >
 216     {
 217     };
 218
 219     //! The metafunction returns the arity of a function
 220     template< typename FunT >
 221     struct arity_of :
 222         public arity_of_impl< FunT >
 223     {
 224     };
 225
 226 } // namespace aux
 227
 228 BOOST_LOG_CLOSE_NAMESPACE // namespace log
 229
 230 } // namespace boost
 231
 232 #include <boost/log/detail/footer.hpp>
 233
 234 #endif // defined(BOOST_NO_SFINAE) || defined(BOOST_MPL_CFG_NO_HAS_XXX)
 235
 236 #endif // BOOST_LOG_DETAIL_FUNCTION_TRAITS_HPP_INCLUDED_