1 // -*- C++ -*-
2 //===----------------------------------------------------------------------===//
3 //
4 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5 // See https://llvm.org/LICENSE.txt for license information.
6 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7 //
8 //===----------------------------------------------------------------------===//
9
10 // For information see https://libcxx.llvm.org/DesignDocs/TimeZone.html
11
12 #ifndef _LIBCPP___CHRONO_EXCEPTION_H
13 #define _LIBCPP___CHRONO_EXCEPTION_H
14
15 #include <version>
16 // Enable the contents of the header only when libc++ was built with experimental features enabled.
17 #if !defined(_LIBCPP_HAS_NO_EXPERIMENTAL_TZDB)
18
19 # include <__chrono/calendar.h>
20 # include <__chrono/local_info.h>
21 # include <__chrono/time_point.h>
22 # include <__config>
23 # include <__configuration/availability.h>
24 # include <__verbose_abort>
25 # include <format>
26 # include <stdexcept>
27 # include <string>
28
29 # if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
30 # pragma GCC system_header
31 # endif
32
33 _LIBCPP_BEGIN_NAMESPACE_STD
34
35 # if _LIBCPP_STD_VER >= 20
36
37 namespace chrono {
38
39 class nonexistent_local_time : public runtime_error {
40 public:
41 template <class _Duration>
nonexistent_local_time(const local_time<_Duration> & __time,const local_info & __info)42 _LIBCPP_HIDE_FROM_ABI nonexistent_local_time(const local_time<_Duration>& __time, const local_info& __info)
43 : runtime_error{__create_message(__time, __info)} {
44 // [time.zone.exception.nonexist]/2
45 // Preconditions: i.result == local_info::nonexistent is true.
46 // The value of __info.result is not used.
47 _LIBCPP_ASSERT_PEDANTIC(__info.result == local_info::nonexistent,
48 "creating an nonexistent_local_time from a local_info that is not non-existent");
49 }
50
51 _LIBCPP_HIDE_FROM_ABI nonexistent_local_time(const nonexistent_local_time&) = default;
52 _LIBCPP_HIDE_FROM_ABI nonexistent_local_time& operator=(const nonexistent_local_time&) = default;
53
54 _LIBCPP_AVAILABILITY_TZDB _LIBCPP_EXPORTED_FROM_ABI ~nonexistent_local_time() override; // exported as key function
55
56 private:
57 template <class _Duration>
__create_message(const local_time<_Duration> & __time,const local_info & __info)58 _LIBCPP_HIDE_FROM_ABI string __create_message(const local_time<_Duration>& __time, const local_info& __info) {
59 return std::format(
60 R"({} is in a gap between
61 {} {} and
62 {} {} which are both equivalent to
63 {} UTC)",
64 __time,
65 local_seconds{__info.first.end.time_since_epoch()} + __info.first.offset,
66 __info.first.abbrev,
67 local_seconds{__info.second.begin.time_since_epoch()} + __info.second.offset,
68 __info.second.abbrev,
69 __info.first.end);
70 }
71 };
72
73 template <class _Duration>
__throw_nonexistent_local_time(const local_time<_Duration> & __time,const local_info & __info)74 _LIBCPP_NORETURN _LIBCPP_AVAILABILITY_TZDB _LIBCPP_HIDE_FROM_ABI void __throw_nonexistent_local_time(
75 [[maybe_unused]] const local_time<_Duration>& __time, [[maybe_unused]] const local_info& __info) {
76 # ifndef _LIBCPP_HAS_NO_EXCEPTIONS
77 throw nonexistent_local_time(__time, __info);
78 # else
79 _LIBCPP_VERBOSE_ABORT("nonexistent_local_time was thrown in -fno-exceptions mode");
80 # endif
81 }
82
83 class ambiguous_local_time : public runtime_error {
84 public:
85 template <class _Duration>
ambiguous_local_time(const local_time<_Duration> & __time,const local_info & __info)86 _LIBCPP_HIDE_FROM_ABI ambiguous_local_time(const local_time<_Duration>& __time, const local_info& __info)
87 : runtime_error{__create_message(__time, __info)} {
88 // [time.zone.exception.ambig]/2
89 // Preconditions: i.result == local_info::ambiguous is true.
90 // The value of __info.result is not used.
91 _LIBCPP_ASSERT_PEDANTIC(__info.result == local_info::ambiguous,
92 "creating an ambiguous_local_time from a local_info that is not ambiguous");
93 }
94
95 _LIBCPP_HIDE_FROM_ABI ambiguous_local_time(const ambiguous_local_time&) = default;
96 _LIBCPP_HIDE_FROM_ABI ambiguous_local_time& operator=(const ambiguous_local_time&) = default;
97
98 _LIBCPP_AVAILABILITY_TZDB _LIBCPP_EXPORTED_FROM_ABI ~ambiguous_local_time() override; // exported as key function
99
100 private:
101 template <class _Duration>
__create_message(const local_time<_Duration> & __time,const local_info & __info)102 _LIBCPP_HIDE_FROM_ABI string __create_message(const local_time<_Duration>& __time, const local_info& __info) {
103 return std::format(
104 // There are two spaces after the full-stop; this has been verified
105 // in the sources of the Standard.
106 R"({0} is ambiguous. It could be
107 {0} {1} == {2} UTC or
108 {0} {3} == {4} UTC)",
109 __time,
110 __info.first.abbrev,
111 __time - __info.first.offset,
112 __info.second.abbrev,
113 __time - __info.second.offset);
114 }
115 };
116
117 template <class _Duration>
__throw_ambiguous_local_time(const local_time<_Duration> & __time,const local_info & __info)118 _LIBCPP_NORETURN _LIBCPP_AVAILABILITY_TZDB _LIBCPP_HIDE_FROM_ABI void __throw_ambiguous_local_time(
119 [[maybe_unused]] const local_time<_Duration>& __time, [[maybe_unused]] const local_info& __info) {
120 # ifndef _LIBCPP_HAS_NO_EXCEPTIONS
121 throw ambiguous_local_time(__time, __info);
122 # else
123 _LIBCPP_VERBOSE_ABORT("ambiguous_local_time was thrown in -fno-exceptions mode");
124 # endif
125 }
126
127 } // namespace chrono
128
129 # endif // _LIBCPP_STD_VER >= 20
130
131 _LIBCPP_END_NAMESPACE_STD
132
133 #endif // !defined(_LIBCPP_HAS_NO_EXPERIMENTAL_TZDB)
134
135 #endif // _LIBCPP___CHRONO_EXCEPTION_H
136