master
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_ZONED_TIME_H
13#define _LIBCPP___CHRONO_ZONED_TIME_H
14
15#include <version>
16// Enable the contents of the header only when libc++ was built with experimental features enabled.
17#if _LIBCPP_HAS_EXPERIMENTAL_TZDB
18
19# include <__chrono/calendar.h>
20# include <__chrono/duration.h>
21# include <__chrono/sys_info.h>
22# include <__chrono/system_clock.h>
23# include <__chrono/time_zone.h>
24# include <__chrono/tzdb_list.h>
25# include <__concepts/constructible.h>
26# include <__config>
27# include <__type_traits/common_type.h>
28# include <__type_traits/conditional.h>
29# include <__type_traits/remove_cvref.h>
30# include <__utility/declval.h>
31# include <__utility/move.h>
32# include <string_view>
33
34# if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
35# pragma GCC system_header
36# endif
37
38_LIBCPP_PUSH_MACROS
39# include <__undef_macros>
40
41_LIBCPP_BEGIN_NAMESPACE_STD
42
43# if _LIBCPP_STD_VER >= 20 && _LIBCPP_HAS_TIME_ZONE_DATABASE && _LIBCPP_HAS_FILESYSTEM && _LIBCPP_HAS_LOCALIZATION
44
45namespace chrono {
46
47template <class>
48struct zoned_traits {};
49
50template <>
51struct zoned_traits<const time_zone*> {
52 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI static const time_zone* default_zone() { return chrono::locate_zone("UTC"); }
53 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI static const time_zone* locate_zone(string_view __name) {
54 return chrono::locate_zone(__name);
55 }
56};
57
58template <class _Duration, class _TimeZonePtr = const time_zone*>
59class zoned_time {
60 // [time.zone.zonedtime.ctor]/2
61 static_assert(__is_duration_v<_Duration>,
62 "the program is ill-formed since _Duration is not a specialization of std::chrono::duration");
63
64 // The wording uses the constraints like
65 // constructible_from<zoned_time, decltype(__traits::locate_zone(string_view{}))>
66 // Using these constraints in the code causes the compiler to give an
67 // error that the constraint depends on itself. To avoid that issue use
68 // the fact it is possible to create this object from a _TimeZonePtr.
69 using __traits _LIBCPP_NODEBUG = zoned_traits<_TimeZonePtr>;
70
71public:
72 using duration = common_type_t<_Duration, seconds>;
73
74 _LIBCPP_HIDE_FROM_ABI zoned_time()
75 requires requires { __traits::default_zone(); }
76 : __zone_{__traits::default_zone()}, __tp_{} {}
77
78 _LIBCPP_HIDE_FROM_ABI zoned_time(const zoned_time&) = default;
79 _LIBCPP_HIDE_FROM_ABI zoned_time& operator=(const zoned_time&) = default;
80
81 _LIBCPP_HIDE_FROM_ABI zoned_time(const sys_time<_Duration>& __tp)
82 requires requires { __traits::default_zone(); }
83 : __zone_{__traits::default_zone()}, __tp_{__tp} {}
84
85 _LIBCPP_HIDE_FROM_ABI explicit zoned_time(_TimeZonePtr __zone) : __zone_{std::move(__zone)}, __tp_{} {}
86
87 _LIBCPP_HIDE_FROM_ABI explicit zoned_time(string_view __name)
88 requires(requires { __traits::locate_zone(string_view{}); } &&
89 constructible_from<_TimeZonePtr, decltype(__traits::locate_zone(string_view{}))>)
90 : __zone_{__traits::locate_zone(__name)}, __tp_{} {}
91
92 template <class _Duration2>
93 _LIBCPP_HIDE_FROM_ABI zoned_time(const zoned_time<_Duration2, _TimeZonePtr>& __zt)
94 requires is_convertible_v<sys_time<_Duration2>, sys_time<_Duration>>
95 : __zone_{__zt.get_time_zone()}, __tp_{__zt.get_sys_time()} {}
96
97 _LIBCPP_HIDE_FROM_ABI zoned_time(_TimeZonePtr __zone, const sys_time<_Duration>& __tp)
98 : __zone_{std::move(__zone)}, __tp_{__tp} {}
99
100 _LIBCPP_HIDE_FROM_ABI zoned_time(string_view __name, const sys_time<_Duration>& __tp)
101 requires requires { _TimeZonePtr{__traits::locate_zone(string_view{})}; }
102 : zoned_time{__traits::locate_zone(__name), __tp} {}
103
104 _LIBCPP_HIDE_FROM_ABI zoned_time(_TimeZonePtr __zone, const local_time<_Duration>& __tp)
105 requires(is_convertible_v<decltype(std::declval<_TimeZonePtr&>() -> to_sys(local_time<_Duration>{})),
106 sys_time<duration>>)
107 : __zone_{std::move(__zone)}, __tp_{__zone_->to_sys(__tp)} {}
108
109 _LIBCPP_HIDE_FROM_ABI zoned_time(string_view __name, const local_time<_Duration>& __tp)
110 requires(requires {
111 _TimeZonePtr{__traits::locate_zone(string_view{})};
112 } && is_convertible_v<decltype(std::declval<_TimeZonePtr&>() -> to_sys(local_time<_Duration>{})),
113 sys_time<duration>>)
114 : zoned_time{__traits::locate_zone(__name), __tp} {}
115
116 _LIBCPP_HIDE_FROM_ABI zoned_time(_TimeZonePtr __zone, const local_time<_Duration>& __tp, choose __c)
117 requires(is_convertible_v<
118 decltype(std::declval<_TimeZonePtr&>() -> to_sys(local_time<_Duration>{}, choose::earliest)),
119 sys_time<duration>>)
120 : __zone_{std::move(__zone)}, __tp_{__zone_->to_sys(__tp, __c)} {}
121
122 _LIBCPP_HIDE_FROM_ABI zoned_time(string_view __name, const local_time<_Duration>& __tp, choose __c)
123 requires(requires {
124 _TimeZonePtr{__traits::locate_zone(string_view{})};
125 } && is_convertible_v<decltype(std::declval<_TimeZonePtr&>() -> to_sys(local_time<_Duration>{}, choose::earliest)),
126 sys_time<duration>>)
127 : zoned_time{__traits::locate_zone(__name), __tp, __c} {}
128
129 template <class _Duration2, class _TimeZonePtr2>
130 _LIBCPP_HIDE_FROM_ABI zoned_time(_TimeZonePtr __zone, const zoned_time<_Duration2, _TimeZonePtr2>& __zt)
131 requires is_convertible_v<sys_time<_Duration2>, sys_time<_Duration>>
132 : __zone_{std::move(__zone)}, __tp_{__zt.get_sys_time()} {}
133
134 // per wording choose has no effect
135 template <class _Duration2, class _TimeZonePtr2>
136 _LIBCPP_HIDE_FROM_ABI zoned_time(_TimeZonePtr __zone, const zoned_time<_Duration2, _TimeZonePtr2>& __zt, choose)
137 requires is_convertible_v<sys_time<_Duration2>, sys_time<_Duration>>
138 : __zone_{std::move(__zone)}, __tp_{__zt.get_sys_time()} {}
139
140 template <class _Duration2, class _TimeZonePtr2>
141 _LIBCPP_HIDE_FROM_ABI zoned_time(string_view __name, const zoned_time<_Duration2, _TimeZonePtr2>& __zt)
142 requires(requires {
143 _TimeZonePtr{__traits::locate_zone(string_view{})};
144 } && is_convertible_v<sys_time<_Duration2>, sys_time<_Duration>>)
145 : zoned_time{__traits::locate_zone(__name), __zt} {}
146
147 template <class _Duration2, class _TimeZonePtr2>
148 _LIBCPP_HIDE_FROM_ABI zoned_time(string_view __name, const zoned_time<_Duration2, _TimeZonePtr2>& __zt, choose __c)
149 requires(requires {
150 _TimeZonePtr{__traits::locate_zone(string_view{})};
151 } && is_convertible_v<sys_time<_Duration2>, sys_time<_Duration>>)
152 : zoned_time{__traits::locate_zone(__name), __zt, __c} {}
153
154 _LIBCPP_HIDE_FROM_ABI zoned_time& operator=(const sys_time<_Duration>& __tp) {
155 __tp_ = __tp;
156 return *this;
157 }
158
159 _LIBCPP_HIDE_FROM_ABI zoned_time& operator=(const local_time<_Duration>& __tp) {
160 // TODO TZDB This seems wrong.
161 // Assigning a non-existent or ambiguous time will throw and not satisfy
162 // the post condition. This seems quite odd; I constructed an object with
163 // choose::earliest and that choice is not respected.
164 // what did LEWG do with this.
165 // MSVC STL and libstdc++ behave the same
166 __tp_ = __zone_->to_sys(__tp);
167 return *this;
168 }
169
170 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI operator sys_time<duration>() const { return get_sys_time(); }
171 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI explicit operator local_time<duration>() const { return get_local_time(); }
172
173 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI _TimeZonePtr get_time_zone() const { return __zone_; }
174 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI local_time<duration> get_local_time() const { return __zone_->to_local(__tp_); }
175 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI sys_time<duration> get_sys_time() const { return __tp_; }
176 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI sys_info get_info() const { return __zone_->get_info(__tp_); }
177
178private:
179 _TimeZonePtr __zone_;
180 sys_time<duration> __tp_;
181};
182
183zoned_time() -> zoned_time<seconds>;
184
185template <class _Duration>
186zoned_time(sys_time<_Duration>) -> zoned_time<common_type_t<_Duration, seconds>>;
187
188template <class _TimeZonePtrOrName>
189using __time_zone_representation _LIBCPP_NODEBUG =
190 conditional_t<is_convertible_v<_TimeZonePtrOrName, string_view>,
191 const time_zone*,
192 remove_cvref_t<_TimeZonePtrOrName>>;
193
194template <class _TimeZonePtrOrName>
195zoned_time(_TimeZonePtrOrName&&) -> zoned_time<seconds, __time_zone_representation<_TimeZonePtrOrName>>;
196
197template <class _TimeZonePtrOrName, class _Duration>
198zoned_time(_TimeZonePtrOrName&&, sys_time<_Duration>)
199 -> zoned_time<common_type_t<_Duration, seconds>, __time_zone_representation<_TimeZonePtrOrName>>;
200
201template <class _TimeZonePtrOrName, class _Duration>
202zoned_time(_TimeZonePtrOrName&&, local_time<_Duration>, choose = choose::earliest)
203 -> zoned_time<common_type_t<_Duration, seconds>, __time_zone_representation<_TimeZonePtrOrName>>;
204
205template <class _Duration, class _TimeZonePtrOrName, class _TimeZonePtr2>
206zoned_time(_TimeZonePtrOrName&&, zoned_time<_Duration, _TimeZonePtr2>, choose = choose::earliest)
207 -> zoned_time<common_type_t<_Duration, seconds>, __time_zone_representation<_TimeZonePtrOrName>>;
208
209using zoned_seconds = zoned_time<seconds>;
210
211template <class _Duration1, class _Duration2, class _TimeZonePtr>
212_LIBCPP_HIDE_FROM_ABI bool
213operator==(const zoned_time<_Duration1, _TimeZonePtr>& __lhs, const zoned_time<_Duration2, _TimeZonePtr>& __rhs) {
214 return __lhs.get_time_zone() == __rhs.get_time_zone() && __lhs.get_sys_time() == __rhs.get_sys_time();
215}
216
217} // namespace chrono
218
219# endif // _LIBCPP_STD_VER >= 20 && _LIBCPP_HAS_TIME_ZONE_DATABASE && _LIBCPP_HAS_FILESYSTEM &&
220 // _LIBCPP_HAS_LOCALIZATION
221
222_LIBCPP_END_NAMESPACE_STD
223
224_LIBCPP_POP_MACROS
225
226#endif // _LIBCPP_HAS_EXPERIMENTAL_TZDB
227
228#endif // _LIBCPP___CHRONO_ZONED_TIME_H