libs/capy/include/boost/capy/cond.hpp

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1		//
2		// Copyright (c) 2025 Vinnie Falco (vinnie.falco@gmail.com)
3		//
4		// Distributed under the Boost Software License, Version 1.0. (See accompanying
5		// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
6		//
7		// Official repository: https://github.com/cppalliance/capy
8		//
9
10		#ifndef BOOST_CAPY_COND_HPP
11		#define BOOST_CAPY_COND_HPP
12
13		#include <boost/capy/detail/config.hpp>
14		#include <system_error>
15
16		namespace boost {
17		namespace capy {
18
19		/** Portable error conditions for capy I/O operations.
20
21		These are the conditions callers should compare against when
22		handling errors from capy operations. The @ref error enum values
23		map to these conditions, as do platform-specific error codes
24		(e.g., `ECANCELED`, SSL EOF errors).
25
26		@par Example
27
28		@code
29		auto [ec, n] = co_await stream.read_some( bufs );
30		if( ec == cond::canceled )
31		// handle cancellation
32		else if( ec == cond::eof )
33		// handle end of stream
34		else if( ec.failed() )
35		// handle other errors
36		@endcode
37
38		@see error
39		*/
40		enum class cond
41		{
42		/** End-of-stream condition.
43
44		An `error_code` compares equal to `eof` when the stream
45		reached its natural end, such as when a peer sends TCP FIN
46		or a file reaches EOF.
47		*/
48		eof = 1,
49
50		/** Operation cancelled condition.
51
52		An `error_code` compares equal to `canceled` when the
53		operation's stop token was activated, the I/O object's
54		`cancel()` was called, or a platform cancellation error
55		occurred.
56		*/
57		canceled = 2,
58
59		/** Stream truncated condition.
60
61		An `error_code` compares equal to `stream_truncated` when
62		a TLS peer closed the connection without sending a proper
63		shutdown alert.
64		*/
65		stream_truncated = 3,
66
67		/** Item not found condition.
68
69		An `error_code` compares equal to `not_found` when a
70		lookup operation failed to find the requested item.
71		*/
72		not_found = 4
73		};
74
75		//-----------------------------------------------
76
77		} // capy
78		} // boost
79
80		namespace std {
81		template<>
82		struct is_error_condition_enum<
83		::boost::capy::cond>
84		: std::true_type {};
85		} // std
86
87		namespace boost {
88		namespace capy {
89
90		//-----------------------------------------------
91
92		namespace detail {
93
94		struct BOOST_CAPY_SYMBOL_VISIBLE
95		cond_cat_type
96		: std::error_category
97		{
98		BOOST_CAPY_DECL const char* name(
99		) const noexcept override;
100		BOOST_CAPY_DECL std::string message(
101		int) const override;
102		BOOST_CAPY_DECL bool equivalent(
103		std::error_code const& ec,
104		int condition) const noexcept override;
105		constexpr cond_cat_type() noexcept = default;
106		};
107
108		BOOST_CAPY_DECL extern cond_cat_type cond_cat;
109
110		} // detail
111
112		//-----------------------------------------------
113
114		inline
115		std::error_condition
116	1010	make_error_condition(
117		cond ev) noexcept
118		{
119	1010	return std::error_condition{
120		static_cast<std::underlying_type<
121		cond>::type>(ev),
122	1010	detail::cond_cat};
123		}
124
125		} // capy
126		} // boost
127
128		#endif
129