ceph/src/boost/boost/callable_traits/apply_member_pointer.hpp

   1 /*
   2
   3 @Copyright Barrett Adair 2015-2017
   4 Distributed under the Boost Software License, Version 1.0.
   5 (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
   6
   7 */
   8
   9 #ifndef BOOST_CLBL_TRTS_APPLY_MEMBER_POINTER_HPP
  10 #define BOOST_CLBL_TRTS_APPLY_MEMBER_POINTER_HPP
  11
  12 #include <boost/callable_traits/detail/core.hpp>
  13
  14 namespace boost { namespace callable_traits {
  15
  16 BOOST_CLBL_TRTS_DEFINE_SFINAE_ERROR_ORIGIN(apply_member_pointer)
  17 BOOST_CLBL_TRTS_SFINAE_MSG(apply_member_pointer, members_cannot_have_a_type_of_void)
  18 BOOST_CLBL_TRTS_SFINAE_MSG(apply_member_pointer, second_template_argument_must_be_a_class_or_struct)
  19
  20 namespace detail {
  21
  22     template<typename T, typename C, bool = std::is_class<C>::value>
  23     struct make_member_pointer;
  24
  25     template<typename T, typename C>
  26     struct make_member_pointer<T, C, true> {
  27         using type = typename std::remove_reference<T>::type C::*;
  28     };
  29
  30     template<typename C>
  31     struct make_member_pointer<void, C, true> {
  32         using type = invalid_type;
  33     };
  34
  35     template<typename T, typename C>
  36     struct make_member_pointer<T, C, false> {
  37         using type = error_type<T>;
  38     };
  39
  40     template<typename T, typename C>
  41     using make_member_pointer_t = typename make_member_pointer<T, C>::type;
  42 }
  43
  44 //[ apply_member_pointer_hpp
  45 /*`
  46 [section:ref_apply_member_pointer apply_member_pointer]
  47 [heading Header]
  48 ``#include <boost/callable_traits/apply_member_pointer.hpp>``
  49 [heading Definition]
  50 */
  51
  52 template<typename T, typename C>
  53 using apply_member_pointer_t = //see below
  54 //<-
  55     detail::sfinae_try<
  56         detail::fallback_if_invalid<
  57             typename detail::traits<T>::template apply_member_pointer<C>,
  58             typename detail::make_member_pointer<T, C>::type>,
  59
  60         detail::fail_when_same<void, T, members_cannot_have_a_type_of_void>,
  61
  62         detail::fail_if<!std::is_class<C>::value,
  63             second_template_argument_must_be_a_class_or_struct> >;
  64
  65 namespace detail {
  66
  67     template<typename T, typename C, typename = std::false_type>
  68     struct apply_member_pointer_impl {};
  69
  70     template<typename T, typename C>
  71     struct apply_member_pointer_impl <T, C, typename std::is_same<
  72         apply_member_pointer_t<T, C>, detail::dummy>::type>
  73     {
  74         using type = apply_member_pointer_t<T, C>;
  75     };
  76 }
  77
  78 //->
  79
  80 template<typename T, typename C>
  81 struct apply_member_pointer : detail::apply_member_pointer_impl<T, C> {};
  82
  83 //<-
  84 }} // namespace boost::callable_traits
  85 //->
  86
  87 /*`
  88 [heading Constraints]
  89 * `T` may be any type except `void`
  90 * `C` must be a user-defined type
  91
  92 [heading Behavior]
  93 * A substitution failure occurs if the constraints are violated.
  94 * When `T` is a function, function pointer (unqualified), or function reference, then the aliased type is a member function pointer of `C` with the same parameters and return type.
  95 * When `T` is a member function pointer (unqualified)  of any type, the aliased type is a member function pointer of `C` with the same parameters and return type.
  96 * Otherwise, the aliased type is a member data pointer equivalent to `std::remove_reference_t<T> C::*`.
  97
  98 [heading Input/Output Examples]
  99 [table
 100     [[`T`]                              [`apply_member_pointer_t<T, foo>`]]
 101     [[`int()`]                          [`int(foo::*)()`]]
 102     [[`int (&)()`]                      [`int(foo::*)()`]]
 103     [[`int (*)()`]                      [`int(foo::*)()`]]
 104     [[`int(bar::*)()`]                  [`int(foo::*)()`]]
 105     [[`int(bar::*)() &`]                [`int(foo::*)() &`]]
 106     [[`int(bar::*)() &&`]               [`int(foo::*)() &&`]]
 107     [[`int(bar::*)() const`]            [`int(foo::*)() const`]]
 108     [[`int(bar::*)() transaction_safe`] [`int(foo::*)() transaction_safe`]]
 109     [[`int bar::*`]                     [`int foo::*`]]
 110     [[`int`]                            [`int foo::*`]]
 111     [[`int &`]                          [`int foo::*`]]
 112     [[`const int &`]                    [`const int foo::*`]]
 113     [[`int (*const)()`]                 [`int (*const foo::*)()`]]
 114     [[`void`]                           [(substitution failure)]]
 115 ]
 116
 117 [heading Example Program]
 118 [import ../example/apply_member_pointer.cpp]
 119 [apply_member_pointer]
 120 [endsect]
 121 */
 122 //]
 123 #endif