ceph/src/boost/boost/type_traits/is_complete.hpp

   1
   2 //  (C) Copyright John Maddock 2017.
   3 //  Use, modification and distribution are subject to the Boost Software License,
   4 //  Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
   5 //  http://www.boost.org/LICENSE_1_0.txt).
   6 //
   7 //  See http://www.boost.org/libs/type_traits for most recent version including documentation.
   8
   9 #ifndef BOOST_TT_IS_COMPLETE_HPP_INCLUDED
  10 #define BOOST_TT_IS_COMPLETE_HPP_INCLUDED
  11
  12 #include <boost/type_traits/declval.hpp>
  13 #include <boost/type_traits/integral_constant.hpp>
  14 #include <boost/type_traits/remove_reference.hpp>
  15 #include <boost/type_traits/is_function.hpp>
  16 #include <boost/type_traits/detail/yes_no_type.hpp>
  17 #include <boost/config/workaround.hpp>
  18
  19 /*
  20  * CAUTION:
  21  * ~~~~~~~~
  22  *
  23  * THIS TRAIT EXISTS SOLELY TO GENERATE HARD ERRORS WHEN A ANOTHER TRAIT
  24  * WHICH REQUIRES COMPLETE TYPES AS ARGUMENTS IS PASSED AN INCOMPLETE TYPE
  25  *
  26  * DO NOT MAKE GENERAL USE OF THIS TRAIT, AS THE COMPLETENESS OF A TYPE
  27  * VARIES ACROSS TRANSLATION UNITS AS WELL AS WITHIN A SINGLE UNIT.
  28  *
  29 */
  30
  31 namespace boost {
  32
  33
  34 //
  35 // We will undef this if the trait isn't fully functional:
  36 //
  37 #define BOOST_TT_HAS_WORKING_IS_COMPLETE
  38
  39 #if !defined(BOOST_NO_SFINAE_EXPR) && !BOOST_WORKAROUND(BOOST_MSVC, <= 1900) && !BOOST_WORKAROUND(BOOST_GCC_VERSION, < 40600)
  40
  41    namespace detail{
  42
  43       template <unsigned N>
  44       struct ok_tag { double d; char c[N]; };
  45
  46       template <class T>
  47       ok_tag<sizeof(T)> check_is_complete(int);
  48       template <class T>
  49       char check_is_complete(...);
  50    }
  51
  52    template <class T> struct is_complete
  53       : public integral_constant<bool, ::boost::is_function<typename boost::remove_reference<T>::type>::value || (sizeof(boost::detail::check_is_complete<T>(0)) != sizeof(char))> {};
  54
  55 #elif !defined(BOOST_NO_SFINAE) && !defined(BOOST_NO_CXX11_FUNCTION_TEMPLATE_DEFAULT_ARGS) && !BOOST_WORKAROUND(BOOST_GCC_VERSION, < 40500)
  56
  57    namespace detail
  58    {
  59
  60       template <class T>
  61       struct is_complete_imp
  62       {
  63          template <class U, class = decltype(sizeof(boost::declval< U >())) >
  64          static type_traits::yes_type check(U*);
  65
  66          template <class U>
  67          static type_traits::no_type check(...);
  68
  69          static const bool value = sizeof(check<T>(0)) == sizeof(type_traits::yes_type);
  70       };
  71
  72 } // namespace detail
  73
  74
  75    template <class T>
  76    struct is_complete : boost::integral_constant<bool, ::boost::is_function<typename boost::remove_reference<T>::type>::value || ::boost::detail::is_complete_imp<T>::value>
  77    {};
  78    template <class T>
  79    struct is_complete<T&> : boost::is_complete<T> {};
  80
  81 #else
  82
  83       template <class T> struct is_complete
  84          : public boost::integral_constant<bool, true> {};
  85
  86 #undef BOOST_TT_HAS_WORKING_IS_COMPLETE
  87
  88 #endif
  89
  90 } // namespace boost
  91
  92 #endif // BOOST_TT_IS_COMPLETE_HPP_INCLUDED