1/* Traits for Outcome
2(C) 2018-2024 Niall Douglas <http://www.nedproductions.biz/> (6 commits)
3File Created: March 2018
4
5
6Boost Software License - Version 1.0 - August 17th, 2003
7
8Permission is hereby granted, free of charge, to any person or organization
9obtaining a copy of the software and accompanying documentation covered by
10this license (the "Software") to use, reproduce, display, distribute,
11execute, and transmit the Software, and to prepare derivative works of the
12Software, and to permit third-parties to whom the Software is furnished to
13do so, all subject to the following:
14
15The copyright notices in the Software and this entire statement, including
16the above license grant, this restriction and the following disclaimer,
17must be included in all copies of the Software, in whole or in part, and
18all derivative works of the Software, unless such copies or derivative
19works are solely in the form of machine-executable object code generated by
20a source language processor.
21
22THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
23IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
24FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
25SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
26FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
27ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
28DEALINGS IN THE SOFTWARE.
29*/
30
31#ifndef BOOST_OUTCOME_TRAIT_STD_ERROR_CODE_HPP
32#define BOOST_OUTCOME_TRAIT_STD_ERROR_CODE_HPP
33
34#include "../config.hpp"
35
36#include <system_error>
37
38BOOST_OUTCOME_V2_NAMESPACE_BEGIN
39
40namespace detail
41{
42 // Customise _set_error_is_errno
43 template <class State> constexpr inline void _set_error_is_errno(State &state, const std::error_code &error)
44 {
45 if(error.category() == std::generic_category()
46#ifndef _WIN32
47 || error.category() == std::system_category()
48#endif
49 )
50 {
51 state._status.set_have_error_is_errno(true);
52 }
53 }
54 template <class State> constexpr inline void _set_error_is_errno(State &state, const std::error_condition &error)
55 {
56 if(error.category() == std::generic_category()
57#ifndef _WIN32
58 || error.category() == std::system_category()
59#endif
60 )
61 {
62 state._status.set_have_error_is_errno(true);
63 }
64 }
65 template <class State> constexpr inline void _set_error_is_errno(State &state, const std::errc & /*unused*/) {
66 state._status.set_have_error_is_errno(true);
67 }
68
69} // namespace detail
70
71namespace policy
72{
73 namespace detail
74 {
75 /* Pass through `make_error_code` function for `std::error_code`.
76 */
77 inline std::error_code make_error_code(std::error_code v) { return v; }
78
79 // Try ADL, if not use fall backs above
80 template <class T> constexpr inline decltype(auto) error_code(T &&v) { return make_error_code(std::forward<T>(v)); }
81
82 struct std_enum_overload_tag
83 {
84 };
85 } // namespace detail
86
87 /*! AWAITING HUGO JSON CONVERSION TOOL
88SIGNATURE NOT RECOGNISED
89*/
90 template <class T> constexpr inline decltype(auto) error_code(T &&v) { return detail::error_code(std::forward<T>(v)); }
91
92 /*! AWAITING HUGO JSON CONVERSION TOOL
93SIGNATURE NOT RECOGNISED
94*/
95 // inline void outcome_throw_as_system_error_with_payload(...) = delete; // To use the error_code_throw_as_system_error policy with a custom Error type, you must define a outcome_throw_as_system_error_with_payload() free function to say how to handle the payload
96 inline void outcome_throw_as_system_error_with_payload(const std::error_code &error) { BOOST_OUTCOME_THROW_EXCEPTION(std::system_error(error)); } // NOLINT
97 BOOST_OUTCOME_TEMPLATE(class Error)
98 BOOST_OUTCOME_TREQUIRES(BOOST_OUTCOME_TPRED(std::is_error_code_enum<std::decay_t<Error>>::value || std::is_error_condition_enum<std::decay_t<Error>>::value))
99 inline void outcome_throw_as_system_error_with_payload(Error &&error, detail::std_enum_overload_tag /*unused*/ = detail::std_enum_overload_tag()) { BOOST_OUTCOME_THROW_EXCEPTION(std::system_error(make_error_code(error))); } // NOLINT
100} // namespace policy
101
102namespace trait
103{
104 namespace detail
105 {
106 template <> struct _is_error_code_available<std::error_code>
107 {
108 // Shortcut this for lower build impact
109 static constexpr bool value = true;
110 using type = std::error_code;
111 };
112 } // namespace detail
113
114 // std::error_code is an error type
115 template <> struct is_error_type<std::error_code>
116 {
117 static constexpr bool value = true;
118 };
119 // For std::error_code, std::is_error_condition_enum<> is the trait we want.
120 template <class Enum> struct is_error_type_enum<std::error_code, Enum>
121 {
122 static constexpr bool value = std::is_error_condition_enum<Enum>::value;
123 };
124
125} // namespace trait
126
127BOOST_OUTCOME_V2_NAMESPACE_END
128
129#endif
130

source code of boost/libs/outcome/include/boost/outcome/detail/trait_std_error_code.hpp