boost/outcome/experimental/status_outcome.hpp

   1 /* A less simple result type
   2 (C) 2018-2019 Niall Douglas <http://www.nedproductions.biz/> (17 commits)
   3 File Created: Apr 2018
   4
   5
   6 Boost Software License - Version 1.0 - August 17th, 2003
   7
   8 Permission is hereby granted, free of charge, to any person or organization
   9 obtaining a copy of the software and accompanying documentation covered by
  10 this license (the "Software") to use, reproduce, display, distribute,
  11 execute, and transmit the Software, and to prepare derivative works of the
  12 Software, and to permit third-parties to whom the Software is furnished to
  13 do so, all subject to the following:
  14
  15 The copyright notices in the Software and this entire statement, including
  16 the above license grant, this restriction and the following disclaimer,
  17 must be included in all copies of the Software, in whole or in part, and
  18 all derivative works of the Software, unless such copies or derivative
  19 works are solely in the form of machine-executable object code generated by
  20 a source language processor.
  21
  22 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  23 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  24 FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
  25 SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
  26 FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
  27 ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  28 DEALINGS IN THE SOFTWARE.
  29 */
  30
  31 #ifndef BOOST_OUTCOME_EXPERIMENTAL_STATUS_OUTCOME_HPP
  32 #define BOOST_OUTCOME_EXPERIMENTAL_STATUS_OUTCOME_HPP
  33
  34 #include "../basic_outcome.hpp"
  35
  36 #include "../detail/trait_std_exception.hpp"
  37 #include "status_result.hpp"
  38
  39 #include "boost/exception_ptr.hpp"
  40
  41 BOOST_OUTCOME_SYSTEM_ERROR2_NAMESPACE_BEGIN
  42 template <class DomainType> inline std::exception_ptr basic_outcome_failure_exception_from_error(const status_code<DomainType> &sc)
  43 {
  44   (void) sc;
  45 #ifndef BOOST_NO_EXCEPTIONS
  46   try
  47   {
  48     sc.throw_exception();
  49   }
  50   catch(...)
  51   {
  52     return std::current_exception();
  53   }
  54 #endif
  55   return {};
  56 }
  57 BOOST_OUTCOME_SYSTEM_ERROR2_NAMESPACE_END
  58
  59 BOOST_OUTCOME_V2_NAMESPACE_EXPORT_BEGIN
  60
  61 namespace experimental
  62 {
  63   namespace policy
  64   {
  65     template <class T, class EC, class E>
  66     using default_status_outcome_policy = std::conditional_t<                                                                                                                              //
  67     std::is_void<EC>::value && std::is_void<E>::value,                                                                                                                                     //
  68     BOOST_OUTCOME_V2_NAMESPACE::policy::terminate,                                                                                                                                               //
  69     std::conditional_t<(is_status_code<EC>::value || is_errored_status_code<EC>::value) && (std::is_void<E>::value || BOOST_OUTCOME_V2_NAMESPACE::trait::is_exception_ptr_available<E>::value),  //
  70                        status_code_throw<T, EC, E>,                                                                                                                                        //
  71                        BOOST_OUTCOME_V2_NAMESPACE::policy::fail_to_compile_observers                                                                                                             //
  72                        >>;
  73   }  // namespace policy
  74
  75   /*! AWAITING HUGO JSON CONVERSION TOOL
  76 SIGNATURE NOT RECOGNISED
  77 */
  78   template <class R, class S = system_code, class P = std::exception_ptr, class NoValuePolicy = policy::default_status_outcome_policy<R, S, P>>  //
  79   using status_outcome = basic_outcome<R, S, P, NoValuePolicy>;
  80
  81   namespace policy
  82   {
  83     template <class T, class DomainType, class E> struct status_code_throw<T, status_code<DomainType>, E> : base
  84     {
  85       using _base = base;
  86       template <class Impl> static constexpr void wide_value_check(Impl &&self)
  87       {
  88         if(!base::_has_value(static_cast<Impl &&>(self)))
  89         {
  90           if(base::_has_exception(static_cast<Impl &&>(self)))
  91           {
  92             BOOST_OUTCOME_V2_NAMESPACE::policy::detail::_rethrow_exception<trait::is_exception_ptr_available<E>::value>(base::_exception<T, status_code<DomainType>, E, status_code_throw>(static_cast<Impl &&>(self)));  // NOLINT
  93           }
  94           if(base::_has_error(static_cast<Impl &&>(self)))
  95           {
  96 #ifndef BOOST_NO_EXCEPTIONS
  97             base::_error(static_cast<Impl &&>(self)).throw_exception();
  98 #else
  99             BOOST_OUTCOME_THROW_EXCEPTION("wide value check failed");
 100 #endif
 101           }
 102         }
 103       }
 104       template <class Impl> static constexpr void wide_error_check(Impl &&self) { _base::narrow_error_check(static_cast<Impl &&>(self)); }
 105       template <class Impl> static constexpr void wide_exception_check(Impl &&self) { _base::narrow_exception_check(static_cast<Impl &&>(self)); }
 106     };
 107     template <class T, class DomainType, class E> struct status_code_throw<T, errored_status_code<DomainType>, E> : status_code_throw<T, status_code<DomainType>, E>
 108     {
 109       status_code_throw() = default;
 110       using status_code_throw<T, status_code<DomainType>, E>::status_code_throw;
 111     };
 112   }  // namespace policy
 113
 114 }  // namespace experimental
 115
 116 BOOST_OUTCOME_V2_NAMESPACE_END
 117
 118 #endif