ceph/src/boost/boost/outcome/detail/basic_outcome_failure_observers.hpp

   1 /* Failure observers for outcome type
   2 (C) 2017-2022 Niall Douglas <http://www.nedproductions.biz/> (7 commits)
   3 File Created: Oct 2017
   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_BASIC_OUTCOME_FAILURE_OBSERVERS_HPP
  32 #define BOOST_OUTCOME_BASIC_OUTCOME_FAILURE_OBSERVERS_HPP
  33
  34 #include "basic_result_storage.hpp"
  35
  36 BOOST_OUTCOME_V2_NAMESPACE_EXPORT_BEGIN
  37
  38 namespace detail
  39 {
  40   namespace adl
  41   {
  42     struct search_detail_adl
  43     {
  44     };
  45     // Do NOT use template requirements here!
  46     template <class S, typename = decltype(basic_outcome_failure_exception_from_error(std::declval<S>()))>
  47     inline auto _delayed_lookup_basic_outcome_failure_exception_from_error(const S &ec, search_detail_adl /*unused*/)
  48     {
  49       // ADL discovered
  50       return basic_outcome_failure_exception_from_error(ec);
  51     }
  52   }                                        // namespace adl
  53 #if defined(_MSC_VER) && _MSC_VER <= 1923  // VS2019
  54   // VS2017 and VS2019 with /permissive- chokes on the correct form due to over eager early instantiation.
  55   template <class S, class P> inline void _delayed_lookup_basic_outcome_failure_exception_from_error(...) { static_assert(sizeof(S) == 0, "No specialisation for these error and exception types available!"); }
  56 #else
  57   template <class S, class P> inline void _delayed_lookup_basic_outcome_failure_exception_from_error(...) = delete;  // NOLINT No specialisation for these error and exception types available!
  58 #endif
  59
  60   template <class exception_type> inline exception_type current_exception_or_fatal(std::exception_ptr e) { std::rethrow_exception(e); }
  61   template <> inline std::exception_ptr current_exception_or_fatal<std::exception_ptr>(std::exception_ptr e) { return e; }
  62
  63   template <class Base, class R, class S, class P, class NoValuePolicy> class basic_outcome_failure_observers : public Base
  64   {
  65   public:
  66     using exception_type = P;
  67     using Base::Base;
  68
  69     exception_type failure() const noexcept
  70     {
  71 #ifndef BOOST_NO_EXCEPTIONS
  72       try
  73 #endif
  74       {
  75         if(this->_state._status.have_exception())
  76         {
  77           return this->assume_exception();
  78         }
  79         if(this->_state._status.have_error())
  80         {
  81           return _delayed_lookup_basic_outcome_failure_exception_from_error(this->assume_error(), adl::search_detail_adl());
  82         }
  83         return exception_type();
  84       }
  85 #ifndef BOOST_NO_EXCEPTIONS
  86       catch(...)
  87       {
  88         // Return the failure if exception_type is std::exception_ptr,
  89         // otherwise terminate same as throwing an exception inside noexcept
  90         return current_exception_or_fatal<exception_type>(std::current_exception());
  91       }
  92 #endif
  93     }
  94   };
  95
  96 }  // namespace detail
  97
  98 BOOST_OUTCOME_V2_NAMESPACE_END
  99
 100 #endif