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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/throw_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#if _LIBCPP_HAS_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
42template <class _Rep, class _Period, __enable_if_t<is_floating_point<_Rep>::value, int> = 0>
43inline _LIBCPP_HIDE_FROM_ABI chrono::nanoseconds __safe_nanosecond_cast(chrono::duration<_Rep, _Period> __d) {
44 using namespace chrono;
45 using __ratio = ratio_divide<_Period, nano>;
46 using __ns_rep = nanoseconds::rep;
47 _Rep __result_float = __d.count() * __ratio::num / __ratio::den;
48
49 _Rep __result_max = numeric_limits<__ns_rep>::max();
50 if (__result_float >= __result_max) {
51 return nanoseconds::max();
52 }
53
54 _Rep __result_min = numeric_limits<__ns_rep>::min();
55 if (__result_float <= __result_min) {
56 return nanoseconds::min();
57 }
58
59 return nanoseconds(static_cast<__ns_rep>(__result_float));
60}
61
62template <class _Rep, class _Period, __enable_if_t<!is_floating_point<_Rep>::value, int> = 0>
63inline _LIBCPP_HIDE_FROM_ABI chrono::nanoseconds __safe_nanosecond_cast(chrono::duration<_Rep, _Period> __d) {
64 using namespace chrono;
65 if (__d.count() == 0) {
66 return nanoseconds(0);
67 }
68
69 using __ratio = ratio_divide<_Period, nano>;
70 using __ns_rep = nanoseconds::rep;
71 __ns_rep __result_max = numeric_limits<__ns_rep>::max();
72 if (__d.count() > 0 && __d.count() > __result_max / __ratio::num) {
73 return nanoseconds::max();
74 }
75
76 __ns_rep __result_min = numeric_limits<__ns_rep>::min();
77 if (__d.count() < 0 && __d.count() < __result_min / __ratio::num) {
78 return nanoseconds::min();
79 }
80
81 __ns_rep __result = __d.count() * __ratio::num / __ratio::den;
82 if (__result == 0) {
83 return nanoseconds(1);
84 }
85
86 return nanoseconds(__result);
87}
88
89class _LIBCPP_EXPORTED_FROM_ABI condition_variable {
90 __libcpp_condvar_t __cv_ = _LIBCPP_CONDVAR_INITIALIZER;
91
92public:
93 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR condition_variable() _NOEXCEPT = default;
94
95# if _LIBCPP_HAS_TRIVIAL_CONDVAR_DESTRUCTION
96 ~condition_variable() = default;
97# else
98 ~condition_variable();
99# endif
100
101 condition_variable(const condition_variable&) = delete;
102 condition_variable& operator=(const condition_variable&) = delete;
103
104 void notify_one() _NOEXCEPT;
105 void notify_all() _NOEXCEPT;
106
107 void wait(unique_lock<mutex>& __lk) _NOEXCEPT;
108
109 template <class _Predicate>
110 _LIBCPP_HIDE_FROM_ABI void wait(unique_lock<mutex>& __lk, _Predicate __pred) {
111 while (!__pred())
112 wait(__lk);
113 }
114
115 template <class _Clock, class _Duration>
116 _LIBCPP_HIDE_FROM_ABI cv_status
117 wait_until(unique_lock<mutex>& __lk, const chrono::time_point<_Clock, _Duration>& __t) {
118 using namespace chrono;
119 using __clock_tp_ns = time_point<_Clock, nanoseconds>;
120
121 typename _Clock::time_point __now = _Clock::now();
122 if (__t <= __now)
123 return cv_status::timeout;
124
125 __clock_tp_ns __t_ns = __clock_tp_ns(std::__safe_nanosecond_cast(__t.time_since_epoch()));
126
127 __do_timed_wait(__lk, __t_ns);
128 return _Clock::now() < __t ? cv_status::no_timeout : cv_status::timeout;
129 }
130
131 template <class _Clock, class _Duration, class _Predicate>
132 _LIBCPP_HIDE_FROM_ABI bool
133 wait_until(unique_lock<mutex>& __lk, const chrono::time_point<_Clock, _Duration>& __t, _Predicate __pred) {
134 while (!__pred()) {
135 if (wait_until(__lk, __t) == cv_status::timeout)
136 return __pred();
137 }
138 return true;
139 }
140
141 template <class _Rep, class _Period>
142 _LIBCPP_HIDE_FROM_ABI cv_status wait_for(unique_lock<mutex>& __lk, const chrono::duration<_Rep, _Period>& __d) {
143 using namespace chrono;
144 if (__d <= __d.zero())
145 return cv_status::timeout;
146 using __ns_rep = nanoseconds::rep;
147 steady_clock::time_point __c_now = steady_clock::now();
148
149# if _LIBCPP_HAS_COND_CLOCKWAIT
150 using __clock_tp_ns = time_point<steady_clock, nanoseconds>;
151 __ns_rep __now_count_ns = std::__safe_nanosecond_cast(__c_now.time_since_epoch()).count();
152# else
153 using __clock_tp_ns = time_point<system_clock, nanoseconds>;
154 __ns_rep __now_count_ns = std::__safe_nanosecond_cast(system_clock::now().time_since_epoch()).count();
155# endif
156
157 __ns_rep __d_ns_count = std::__safe_nanosecond_cast(__d).count();
158
159 if (__now_count_ns > numeric_limits<__ns_rep>::max() - __d_ns_count) {
160 __do_timed_wait(__lk, __clock_tp_ns::max());
161 } else {
162 __do_timed_wait(__lk, __clock_tp_ns(nanoseconds(__now_count_ns + __d_ns_count)));
163 }
164
165 return steady_clock::now() - __c_now < __d ? cv_status::no_timeout : cv_status::timeout;
166 }
167
168 template <class _Rep, class _Period, class _Predicate>
169 bool _LIBCPP_HIDE_FROM_ABI
170 wait_for(unique_lock<mutex>& __lk, const chrono::duration<_Rep, _Period>& __d, _Predicate __pred);
171
172 typedef __libcpp_condvar_t* native_handle_type;
173 _LIBCPP_HIDE_FROM_ABI native_handle_type native_handle() { return &__cv_; }
174
175private:
176 void
177 __do_timed_wait(unique_lock<mutex>& __lk, chrono::time_point<chrono::system_clock, chrono::nanoseconds>) _NOEXCEPT;
178# if _LIBCPP_HAS_COND_CLOCKWAIT
179 _LIBCPP_HIDE_FROM_ABI void
180 __do_timed_wait(unique_lock<mutex>& __lk, chrono::time_point<chrono::steady_clock, chrono::nanoseconds>) _NOEXCEPT;
181# endif
182 template <class _Clock>
183 _LIBCPP_HIDE_FROM_ABI void
184 __do_timed_wait(unique_lock<mutex>& __lk, chrono::time_point<_Clock, chrono::nanoseconds>) _NOEXCEPT;
185};
186#endif // _LIBCPP_HAS_THREADS
187
188#if _LIBCPP_HAS_THREADS
189
190template <class _Rep, class _Period, class _Predicate>
191inline bool
192condition_variable::wait_for(unique_lock<mutex>& __lk, const chrono::duration<_Rep, _Period>& __d, _Predicate __pred) {
193 return wait_until(__lk, chrono::steady_clock::now() + __d, std::move(__pred));
194}
195
196# if _LIBCPP_HAS_COND_CLOCKWAIT
197inline void condition_variable::__do_timed_wait(
198 unique_lock<mutex>& __lk, chrono::time_point<chrono::steady_clock, chrono::nanoseconds> __tp) _NOEXCEPT {
199 using namespace chrono;
200 if (!__lk.owns_lock())
201 std::__throw_system_error(EPERM, "condition_variable::timed wait: mutex not locked");
202 nanoseconds __d = __tp.time_since_epoch();
203 timespec __ts;
204 seconds __s = duration_cast<seconds>(__d);
205 using __ts_sec = decltype(__ts.tv_sec);
206 const __ts_sec __ts_sec_max = numeric_limits<__ts_sec>::max();
207 if (__s.count() < __ts_sec_max) {
208 __ts.tv_sec = static_cast<__ts_sec>(__s.count());
209 __ts.tv_nsec = (__d - __s).count();
210 } else {
211 __ts.tv_sec = __ts_sec_max;
212 __ts.tv_nsec = giga::num - 1;
213 }
214 int __ec = pthread_cond_clockwait(&__cv_, __lk.mutex()->native_handle(), CLOCK_MONOTONIC, &__ts);
215 if (__ec != 0 && __ec != ETIMEDOUT)
216 std::__throw_system_error(__ec, "condition_variable timed_wait failed");
217}
218# endif // _LIBCPP_HAS_COND_CLOCKWAIT
219
220template <class _Clock>
221inline void condition_variable::__do_timed_wait(unique_lock<mutex>& __lk,
222 chrono::time_point<_Clock, chrono::nanoseconds> __tp) _NOEXCEPT {
223 wait_for(__lk, __tp - _Clock::now());
224}
225
226#endif // _LIBCPP_HAS_THREADS
227
228_LIBCPP_END_NAMESPACE_STD
229
230_LIBCPP_POP_MACROS
231
232#endif // _LIBCPP___CONDITION_VARIABLE_CONDITION_VARIABLE_H