/* Traits for Outcome
(C) 2018-2019 Niall Douglas <http://www.nedproductions.biz/> (8 commits)
File Created: March 2018


Boost Software License - Version 1.0 - August 17th, 2003

Permission is hereby granted, free of charge, to any person or organization
obtaining a copy of the software and accompanying documentation covered by
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The copyright notices in the Software and this entire statement, including
the above license grant, this restriction and the following disclaimer,
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SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
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*/

#ifndef BOOST_OUTCOME_TRAIT_HPP
#define BOOST_OUTCOME_TRAIT_HPP

#include "config.hpp"

BOOST_OUTCOME_V2_NAMESPACE_BEGIN

namespace trait
{
  /*! AWAITING HUGO JSON CONVERSION TOOL
SIGNATURE NOT RECOGNISED
*/
  template <class R>                                                             //
  static constexpr bool type_can_be_used_in_basic_result =                       //
  (!std::is_reference<R>::value                                                  //
   && !BOOST_OUTCOME_V2_NAMESPACE::detail::is_in_place_type_t<std::decay_t<R>>::value  //
   && !is_success_type<R>                                                        //
   && !is_failure_type<R>                                                        //
   && !std::is_array<R>::value                                                   //
   && (std::is_void<R>::value || (std::is_object<R>::value                       //
                                  && std::is_destructible<R>::value))            //
  );

  /*! AWAITING HUGO JSON CONVERSION TOOL
type definition  is_error_type. Potential doc page: NOT FOUND
*/
  template <class E> struct is_error_type
  {
    static constexpr bool value = false;
  };

  /*! AWAITING HUGO JSON CONVERSION TOOL
type definition  is_error_type_enum. Potential doc page: NOT FOUND
*/
  template <class E, class Enum> struct is_error_type_enum
  {
    static constexpr bool value = false;
  };

  namespace detail
  {
    template <class T> using devoid = BOOST_OUTCOME_V2_NAMESPACE::detail::devoid<T>;
    template <class T> std::add_rvalue_reference_t<devoid<T>> declval() noexcept;

    // From http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/n4436.pdf
    namespace detector_impl
    {
      template <class...> using void_t = void;
      template <class Default, class, template <class...> class Op, class... Args> struct detector
      {
        static constexpr bool value = false;
        using type = Default;
      };
      template <class Default, template <class...> class Op, class... Args> struct detector<Default, void_t<Op<Args...>>, Op, Args...>
      {
        static constexpr bool value = true;
        using type = Op<Args...>;
      };
    }  // namespace detector_impl
    template <template <class...> class Op, class... Args> using is_detected = detector_impl::detector<void, void, Op, Args...>;

    template <class Arg> using result_of_make_error_code = decltype(make_error_code(declval<Arg>()));
    template <class Arg> using introspect_make_error_code = is_detected<result_of_make_error_code, Arg>;

    template <class Arg> using result_of_make_exception_ptr = decltype(make_exception_ptr(declval<Arg>()));
    template <class Arg> using introspect_make_exception_ptr = is_detected<result_of_make_exception_ptr, Arg>;

    template <class T> struct _is_error_code_available
    {
      static constexpr bool value = detail::introspect_make_error_code<T>::value;
      using type = typename detail::introspect_make_error_code<T>::type;
    };
    template <class T> struct _is_exception_ptr_available
    {
      static constexpr bool value = detail::introspect_make_exception_ptr<T>::value;
      using type = typename detail::introspect_make_exception_ptr<T>::type;
    };
  }  // namespace detail

  /*! AWAITING HUGO JSON CONVERSION TOOL
type definition  is_error_code_available. Potential doc page: NOT FOUND
*/
  template <class T> struct is_error_code_available
  {
    static constexpr bool value = detail::_is_error_code_available<std::decay_t<T>>::value;
    using type = typename detail::_is_error_code_available<std::decay_t<T>>::type;
  };
  template <class T> constexpr bool is_error_code_available_v = detail::_is_error_code_available<std::decay_t<T>>::value;

  /*! AWAITING HUGO JSON CONVERSION TOOL
type definition  is_exception_ptr_available. Potential doc page: NOT FOUND
*/
  template <class T> struct is_exception_ptr_available
  {
    static constexpr bool value = detail::_is_exception_ptr_available<std::decay_t<T>>::value;
    using type = typename detail::_is_exception_ptr_available<std::decay_t<T>>::type;
  };
  template <class T> constexpr bool is_exception_ptr_available_v = detail::_is_exception_ptr_available<std::decay_t<T>>::value;


}  // namespace trait

BOOST_OUTCOME_V2_NAMESPACE_END

#endif