experimental/status-code/system_code_from_exception.hpp

0001 /* Proposed SG14 status_code
0002 (C) 2018-2024 Niall Douglas <http://www.nedproductions.biz/> (5 commits)
0003 File Created: June 2018
0004
0005
0006 Boost Software License - Version 1.0 - August 17th, 2003
0007
0008 Permission is hereby granted, free of charge, to any person or organization
0009 obtaining a copy of the software and accompanying documentation covered by
0010 this license (the "Software") to use, reproduce, display, distribute,
0011 execute, and transmit the Software, and to prepare derivative works of the
0012 Software, and to permit third-parties to whom the Software is furnished to
0013 do so, all subject to the following:
0014
0015 The copyright notices in the Software and this entire statement, including
0016 the above license grant, this restriction and the following disclaimer,
0017 must be included in all copies of the Software, in whole or in part, and
0018 all derivative works of the Software, unless such copies or derivative
0019 works are solely in the form of machine-executable object code generated by
0020 a source language processor.
0021
0022 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
0023 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
0024 FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
0025 SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
0026 FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
0027 ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
0028 DEALINGS IN THE SOFTWARE.
0029 */
0030
0031 #ifndef BOOST_OUTCOME_SYSTEM_ERROR2_SYSTEM_CODE_FROM_EXCEPTION_HPP
0032 #define BOOST_OUTCOME_SYSTEM_ERROR2_SYSTEM_CODE_FROM_EXCEPTION_HPP
0033
0034 #include "system_code.hpp"
0035
0036 #include "status_error.hpp"
0037
0038 #include <exception>     // for exception_ptr
0039 #include <stdexcept>     // for the exception types
0040 #include <system_error>  // for std::system_error
0041
0042 BOOST_OUTCOME_SYSTEM_ERROR2_NAMESPACE_BEGIN
0043
0044 /*! A utility function which returns the closest matching system_code to a supplied
0045 exception ptr.
0046 */
0047 inline system_code system_code_from_exception(std::exception_ptr &&ep = std::current_exception(),
0048                                               system_code not_matched = generic_code(errc::resource_unavailable_try_again)) noexcept
0049 {
0050   if(!ep)
0051   {
0052     return generic_code(errc::success);
0053   }
0054   try
0055   {
0056     try
0057     {
0058       std::rethrow_exception(ep);
0059     }
0060     catch(const status_error<void> &e)
0061     {
0062       try
0063       {
0064         system_code erased(in_place, e.code());
0065         if(!erased.empty())
0066         {
0067           return erased;
0068         }
0069       }
0070       catch(...)
0071       {
0072         // Source status code's do_erased_copy() routine refused to copy the original
0073         // Process instead as if the source were not a status_error
0074       }
0075       throw;
0076     }
0077     catch(...)
0078     {
0079       throw;
0080     }
0081   }
0082   catch(const std::invalid_argument & /*unused*/)
0083   {
0084     ep = std::exception_ptr();
0085     return generic_code(errc::invalid_argument);
0086   }
0087   catch(const std::domain_error & /*unused*/)
0088   {
0089     ep = std::exception_ptr();
0090     return generic_code(errc::argument_out_of_domain);
0091   }
0092   catch(const std::length_error & /*unused*/)
0093   {
0094     ep = std::exception_ptr();
0095     return generic_code(errc::argument_list_too_long);
0096   }
0097   catch(const std::out_of_range & /*unused*/)
0098   {
0099     ep = std::exception_ptr();
0100     return generic_code(errc::result_out_of_range);
0101   }
0102   catch(const std::logic_error & /*unused*/) /* base class for this group */
0103   {
0104     ep = std::exception_ptr();
0105     return generic_code(errc::invalid_argument);
0106   }
0107   catch(const std::system_error &e) /* also catches ios::failure */
0108   {
0109     ep = std::exception_ptr();
0110     if(e.code().category() == std::generic_category())
0111     {
0112       return generic_code(static_cast<errc>(static_cast<int>(e.code().value())));
0113     }
0114     if(e.code().category() == std::system_category())
0115     {
0116 #ifdef _WIN32
0117       return win32_code(e.code().value());
0118 #else
0119 #ifndef BOOST_OUTCOME_SYSTEM_ERROR2_NOT_POSIX
0120       return posix_code(e.code().value());
0121 #else
0122       return generic_code(static_cast<errc>(e.code().value()));
0123 #endif
0124 #endif
0125     }
0126     // Don't know this error code category, can't wrap it into std_error_code
0127     // as its payload won't fit into system_code, so fall through.
0128   }
0129   catch(const std::overflow_error & /*unused*/)
0130   {
0131     ep = std::exception_ptr();
0132     return generic_code(errc::value_too_large);
0133   }
0134   catch(const std::range_error & /*unused*/)
0135   {
0136     ep = std::exception_ptr();
0137     return generic_code(errc::result_out_of_range);
0138   }
0139   catch(const std::runtime_error & /*unused*/) /* base class for this group */
0140   {
0141     ep = std::exception_ptr();
0142     return generic_code(errc::resource_unavailable_try_again);
0143   }
0144   catch(const std::bad_alloc & /*unused*/)
0145   {
0146     ep = std::exception_ptr();
0147     return generic_code(errc::not_enough_memory);
0148   }
0149   catch(...)
0150   {
0151   }
0152   return not_matched;
0153 }
0154
0155 BOOST_OUTCOME_SYSTEM_ERROR2_NAMESPACE_END
0156
0157 #endif