1 /* Proposed SG14 status_code
2 (C) 2018-2019 Niall Douglas <http://www.nedproductions.biz/> (5 commits)
6 Boost Software License - Version 1.0 - August 17th, 2003
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31 #ifndef BOOST_OUTCOME_SYSTEM_ERROR2_POSIX_CODE_HPP
32 #define BOOST_OUTCOME_SYSTEM_ERROR2_POSIX_CODE_HPP
34 #include "generic_code.hpp"
36 #include <cstring> // for strchr and strerror_r
38 BOOST_OUTCOME_SYSTEM_ERROR2_NAMESPACE_BEGIN
40 class _posix_code_domain;
41 //! A POSIX error code, those returned by `errno`.
42 using posix_code = status_code<_posix_code_domain>;
43 //! A specialisation of `status_error` for the POSIX error code domain.
44 using posix_error = status_error<_posix_code_domain>;
46 /*! The implementation of the domain for POSIX error codes, those returned by `errno`.
48 class _posix_code_domain : public status_code_domain
50 template <class DomainType> friend class status_code;
51 template <class StatusCode> friend class detail::indirecting_domain;
52 using _base = status_code_domain;
54 static _base::string_ref _make_string_ref(int c) noexcept
56 char buffer[1024] = "";
58 strerror_s(buffer, sizeof(buffer), c);
59 #elif defined(__gnu_linux__) && !defined(__ANDROID__) // handle glibc's weird strerror_r()
60 char *s = strerror_r(c, buffer, sizeof(buffer)); // NOLINT
63 strncpy(buffer, s, sizeof(buffer)); // NOLINT
67 strerror_r(c, buffer, sizeof(buffer));
69 size_t length = strlen(buffer); // NOLINT
70 auto *p = static_cast<char *>(malloc(length + 1)); // NOLINT
73 return _base::string_ref("failed to get message from system");
75 memcpy(p, buffer, length + 1); // NOLINT
76 return _base::atomic_refcounted_string_ref(p, length);
80 //! The value type of the POSIX code, which is an `int`
81 using value_type = int;
82 using _base::string_ref;
84 //! Default constructor
85 constexpr explicit _posix_code_domain(typename _base::unique_id_type id = 0xa59a56fe5f310933) noexcept : _base(id) {}
86 _posix_code_domain(const _posix_code_domain &) = default;
87 _posix_code_domain(_posix_code_domain &&) = default;
88 _posix_code_domain &operator=(const _posix_code_domain &) = default;
89 _posix_code_domain &operator=(_posix_code_domain &&) = default;
90 ~_posix_code_domain() = default;
92 //! Constexpr singleton getter. Returns constexpr posix_code_domain variable.
93 static inline constexpr const _posix_code_domain &get();
95 virtual string_ref name() const noexcept override { return string_ref("posix domain"); } // NOLINT
97 virtual bool _do_failure(const status_code<void> &code) const noexcept override // NOLINT
99 assert(code.domain() == *this); // NOLINT
100 return static_cast<const posix_code &>(code).value() != 0; // NOLINT
102 virtual bool _do_equivalent(const status_code<void> &code1, const status_code<void> &code2) const noexcept override // NOLINT
104 assert(code1.domain() == *this); // NOLINT
105 const auto &c1 = static_cast<const posix_code &>(code1); // NOLINT
106 if(code2.domain() == *this)
108 const auto &c2 = static_cast<const posix_code &>(code2); // NOLINT
109 return c1.value() == c2.value();
111 if(code2.domain() == generic_code_domain)
113 const auto &c2 = static_cast<const generic_code &>(code2); // NOLINT
114 if(static_cast<int>(c2.value()) == c1.value())
121 virtual generic_code _generic_code(const status_code<void> &code) const noexcept override // NOLINT
123 assert(code.domain() == *this); // NOLINT
124 const auto &c = static_cast<const posix_code &>(code); // NOLINT
125 return generic_code(static_cast<errc>(c.value()));
127 virtual string_ref _do_message(const status_code<void> &code) const noexcept override // NOLINT
129 assert(code.domain() == *this); // NOLINT
130 const auto &c = static_cast<const posix_code &>(code); // NOLINT
131 return _make_string_ref(c.value());
133 #if defined(_CPPUNWIND) || defined(__EXCEPTIONS) || defined(BOOST_OUTCOME_STANDARDESE_IS_IN_THE_HOUSE)
134 BOOST_OUTCOME_SYSTEM_ERROR2_NORETURN virtual void _do_throw_exception(const status_code<void> &code) const override // NOLINT
136 assert(code.domain() == *this); // NOLINT
137 const auto &c = static_cast<const posix_code &>(code); // NOLINT
138 throw status_error<_posix_code_domain>(c);
142 //! A constexpr source variable for the POSIX code domain, which is that of `errno`. Returned by `_posix_code_domain::get()`.
143 constexpr _posix_code_domain posix_code_domain;
144 inline constexpr const _posix_code_domain &_posix_code_domain::get()
146 return posix_code_domain;
149 BOOST_OUTCOME_SYSTEM_ERROR2_NAMESPACE_END