1//===----------------------------------------------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#ifndef _LIBCPP___CONDITION_VARIABLE_CONDITION_VARIABLE_H
10#define _LIBCPP___CONDITION_VARIABLE_CONDITION_VARIABLE_H
11
12#include <__chrono/duration.h>
13#include <__chrono/steady_clock.h>
14#include <__chrono/system_clock.h>
15#include <__chrono/time_point.h>
16#include <__config>
17#include <__mutex/mutex.h>
18#include <__mutex/unique_lock.h>
19#include <__system_error/system_error.h>
20#include <__thread/support.h>
21#include <__type_traits/enable_if.h>
22#include <__type_traits/is_floating_point.h>
23#include <__utility/move.h>
24#include <limits>
25#include <ratio>
26
27#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
28# pragma GCC system_header
29#endif
30
31_LIBCPP_PUSH_MACROS
32#include <__undef_macros>
33
34_LIBCPP_BEGIN_NAMESPACE_STD
35
36#ifndef _LIBCPP_HAS_NO_THREADS
37
38// enum class cv_status
39_LIBCPP_DECLARE_STRONG_ENUM(cv_status){no_timeout, timeout};
40_LIBCPP_DECLARE_STRONG_ENUM_EPILOG(cv_status)
41
42class _LIBCPP_EXPORTED_FROM_ABI condition_variable {
43 __libcpp_condvar_t __cv_ = _LIBCPP_CONDVAR_INITIALIZER;
44
45public:
46 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR condition_variable() _NOEXCEPT = default;
47
48# ifdef _LIBCPP_HAS_TRIVIAL_CONDVAR_DESTRUCTION
49 ~condition_variable() = default;
50# else
51 ~condition_variable();
52# endif
53
54 condition_variable(const condition_variable&) = delete;
55 condition_variable& operator=(const condition_variable&) = delete;
56
57 void notify_one() _NOEXCEPT;
58 void notify_all() _NOEXCEPT;
59
60 void wait(unique_lock<mutex>& __lk) _NOEXCEPT;
61 template <class _Predicate>
62 _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS void wait(unique_lock<mutex>& __lk, _Predicate __pred);
63
64 template <class _Clock, class _Duration>
65 _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS cv_status
66 wait_until(unique_lock<mutex>& __lk, const chrono::time_point<_Clock, _Duration>& __t);
67
68 template <class _Clock, class _Duration, class _Predicate>
69 _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS bool
70 wait_until(unique_lock<mutex>& __lk, const chrono::time_point<_Clock, _Duration>& __t, _Predicate __pred);
71
72 template <class _Rep, class _Period>
73 _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS cv_status
74 wait_for(unique_lock<mutex>& __lk, const chrono::duration<_Rep, _Period>& __d);
75
76 template <class _Rep, class _Period, class _Predicate>
77 bool _LIBCPP_HIDE_FROM_ABI
78 wait_for(unique_lock<mutex>& __lk, const chrono::duration<_Rep, _Period>& __d, _Predicate __pred);
79
80 typedef __libcpp_condvar_t* native_handle_type;
81 _LIBCPP_HIDE_FROM_ABI native_handle_type native_handle() { return &__cv_; }
82
83private:
84 void
85 __do_timed_wait(unique_lock<mutex>& __lk, chrono::time_point<chrono::system_clock, chrono::nanoseconds>) _NOEXCEPT;
86# if defined(_LIBCPP_HAS_COND_CLOCKWAIT)
87 _LIBCPP_HIDE_FROM_ABI void
88 __do_timed_wait(unique_lock<mutex>& __lk, chrono::time_point<chrono::steady_clock, chrono::nanoseconds>) _NOEXCEPT;
89# endif
90 template <class _Clock>
91 _LIBCPP_HIDE_FROM_ABI void
92 __do_timed_wait(unique_lock<mutex>& __lk, chrono::time_point<_Clock, chrono::nanoseconds>) _NOEXCEPT;
93};
94#endif // !_LIBCPP_HAS_NO_THREADS
95
96template <class _Rep, class _Period, __enable_if_t<is_floating_point<_Rep>::value, int> = 0>
97inline _LIBCPP_HIDE_FROM_ABI chrono::nanoseconds __safe_nanosecond_cast(chrono::duration<_Rep, _Period> __d) {
98 using namespace chrono;
99 using __ratio = ratio_divide<_Period, nano>;
100 using __ns_rep = nanoseconds::rep;
101 _Rep __result_float = __d.count() * __ratio::num / __ratio::den;
102
103 _Rep __result_max = numeric_limits<__ns_rep>::max();
104 if (__result_float >= __result_max) {
105 return nanoseconds::max();
106 }
107
108 _Rep __result_min = numeric_limits<__ns_rep>::min();
109 if (__result_float <= __result_min) {
110 return nanoseconds::min();
111 }
112
113 return nanoseconds(static_cast<__ns_rep>(__result_float));
114}
115
116template <class _Rep, class _Period, __enable_if_t<!is_floating_point<_Rep>::value, int> = 0>
117inline _LIBCPP_HIDE_FROM_ABI chrono::nanoseconds __safe_nanosecond_cast(chrono::duration<_Rep, _Period> __d) {
118 using namespace chrono;
119 if (__d.count() == 0) {
120 return nanoseconds(0);
121 }
122
123 using __ratio = ratio_divide<_Period, nano>;
124 using __ns_rep = nanoseconds::rep;
125 __ns_rep __result_max = numeric_limits<__ns_rep>::max();
126 if (__d.count() > 0 && __d.count() > __result_max / __ratio::num) {
127 return nanoseconds::max();
128 }
129
130 __ns_rep __result_min = numeric_limits<__ns_rep>::min();
131 if (__d.count() < 0 && __d.count() < __result_min / __ratio::num) {
132 return nanoseconds::min();
133 }
134
135 __ns_rep __result = __d.count() * __ratio::num / __ratio::den;
136 if (__result == 0) {
137 return nanoseconds(1);
138 }
139
140 return nanoseconds(__result);
141}
142
143#ifndef _LIBCPP_HAS_NO_THREADS
144template <class _Predicate>
145void condition_variable::wait(unique_lock<mutex>& __lk, _Predicate __pred) {
146 while (!__pred())
147 wait(__lk);
148}
149
150template <class _Clock, class _Duration>
151cv_status condition_variable::wait_until(unique_lock<mutex>& __lk, const chrono::time_point<_Clock, _Duration>& __t) {
152 using namespace chrono;
153 using __clock_tp_ns = time_point<_Clock, nanoseconds>;
154
155 typename _Clock::time_point __now = _Clock::now();
156 if (__t <= __now)
157 return cv_status::timeout;
158
159 __clock_tp_ns __t_ns = __clock_tp_ns(std::__safe_nanosecond_cast(__t.time_since_epoch()));
160
161 __do_timed_wait(__lk, __t_ns);
162 return _Clock::now() < __t ? cv_status::no_timeout : cv_status::timeout;
163}
164
165template <class _Clock, class _Duration, class _Predicate>
166bool condition_variable::wait_until(
167 unique_lock<mutex>& __lk, const chrono::time_point<_Clock, _Duration>& __t, _Predicate __pred) {
168 while (!__pred()) {
169 if (wait_until(__lk, __t) == cv_status::timeout)
170 return __pred();
171 }
172 return true;
173}
174
175template <class _Rep, class _Period>
176cv_status condition_variable::wait_for(unique_lock<mutex>& __lk, const chrono::duration<_Rep, _Period>& __d) {
177 using namespace chrono;
178 if (__d <= __d.zero())
179 return cv_status::timeout;
180 using __ns_rep = nanoseconds::rep;
181 steady_clock::time_point __c_now = steady_clock::now();
182
183# if defined(_LIBCPP_HAS_COND_CLOCKWAIT)
184 using __clock_tp_ns = time_point<steady_clock, nanoseconds>;
185 __ns_rep __now_count_ns = std::__safe_nanosecond_cast(__c_now.time_since_epoch()).count();
186# else
187 using __clock_tp_ns = time_point<system_clock, nanoseconds>;
188 __ns_rep __now_count_ns = std::__safe_nanosecond_cast(system_clock::now().time_since_epoch()).count();
189# endif
190
191 __ns_rep __d_ns_count = std::__safe_nanosecond_cast(__d).count();
192
193 if (__now_count_ns > numeric_limits<__ns_rep>::max() - __d_ns_count) {
194 __do_timed_wait(__lk, __clock_tp_ns::max());
195 } else {
196 __do_timed_wait(__lk, __clock_tp_ns(nanoseconds(__now_count_ns + __d_ns_count)));
197 }
198
199 return steady_clock::now() - __c_now < __d ? cv_status::no_timeout : cv_status::timeout;
200}
201
202template <class _Rep, class _Period, class _Predicate>
203inline bool
204condition_variable::wait_for(unique_lock<mutex>& __lk, const chrono::duration<_Rep, _Period>& __d, _Predicate __pred) {
205 return wait_until(__lk, chrono::steady_clock::now() + __d, std::move(__pred));
206}
207
208# if defined(_LIBCPP_HAS_COND_CLOCKWAIT)
209inline void condition_variable::__do_timed_wait(
210 unique_lock<mutex>& __lk, chrono::time_point<chrono::steady_clock, chrono::nanoseconds> __tp) _NOEXCEPT {
211 using namespace chrono;
212 if (!__lk.owns_lock())
213 __throw_system_error(EPERM, "condition_variable::timed wait: mutex not locked");
214 nanoseconds __d = __tp.time_since_epoch();
215 timespec __ts;
216 seconds __s = duration_cast<seconds>(__d);
217 using __ts_sec = decltype(__ts.tv_sec);
218 const __ts_sec __ts_sec_max = numeric_limits<__ts_sec>::max();
219 if (__s.count() < __ts_sec_max) {
220 __ts.tv_sec = static_cast<__ts_sec>(__s.count());
221 __ts.tv_nsec = (__d - __s).count();
222 } else {
223 __ts.tv_sec = __ts_sec_max;
224 __ts.tv_nsec = giga::num - 1;
225 }
226 int __ec = pthread_cond_clockwait(&__cv_, __lk.mutex()->native_handle(), CLOCK_MONOTONIC, &__ts);
227 if (__ec != 0 && __ec != ETIMEDOUT)
228 __throw_system_error(__ec, "condition_variable timed_wait failed");
229}
230# endif // _LIBCPP_HAS_COND_CLOCKWAIT
231
232template <class _Clock>
233inline void condition_variable::__do_timed_wait(unique_lock<mutex>& __lk,
234 chrono::time_point<_Clock, chrono::nanoseconds> __tp) _NOEXCEPT {
235 wait_for(__lk, __tp - _Clock::now());
236}
237
238#endif // _LIBCPP_HAS_NO_THREADS
239
240_LIBCPP_END_NAMESPACE_STD
241
242_LIBCPP_POP_MACROS
243
244#endif // _LIBCPP___CONDITION_VARIABLE_CONDITION_VARIABLE_H
245