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
_LIBCPP_DECLARE_STRONG_ENUM(cv_status)39 _LIBCPP_DECLARE_STRONG_ENUM(cv_status){no_timeout, timeout};
_LIBCPP_DECLARE_STRONG_ENUM_EPILOG(cv_status)40 _LIBCPP_DECLARE_STRONG_ENUM_EPILOG(cv_status)
41
42 class _LIBCPP_EXPORTED_FROM_ABI condition_variable {
43 __libcpp_condvar_t __cv_ = _LIBCPP_CONDVAR_INITIALIZER;
44
45 public:
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
83 private:
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
96 template <class _Rep, class _Period, __enable_if_t<is_floating_point<_Rep>::value, int> = 0>
__safe_nanosecond_cast(chrono::duration<_Rep,_Period> __d)97 inline _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
116 template <class _Rep, class _Period, __enable_if_t<!is_floating_point<_Rep>::value, int> = 0>
__safe_nanosecond_cast(chrono::duration<_Rep,_Period> __d)117 inline _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
144 template <class _Predicate>
wait(unique_lock<mutex> & __lk,_Predicate __pred)145 void condition_variable::wait(unique_lock<mutex>& __lk, _Predicate __pred) {
146 while (!__pred())
147 wait(__lk);
148 }
149
150 template <class _Clock, class _Duration>
wait_until(unique_lock<mutex> & __lk,const chrono::time_point<_Clock,_Duration> & __t)151 cv_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
165 template <class _Clock, class _Duration, class _Predicate>
wait_until(unique_lock<mutex> & __lk,const chrono::time_point<_Clock,_Duration> & __t,_Predicate __pred)166 bool 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
175 template <class _Rep, class _Period>
wait_for(unique_lock<mutex> & __lk,const chrono::duration<_Rep,_Period> & __d)176 cv_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
202 template <class _Rep, class _Period, class _Predicate>
203 inline bool
wait_for(unique_lock<mutex> & __lk,const chrono::duration<_Rep,_Period> & __d,_Predicate __pred)204 condition_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)
__do_timed_wait(unique_lock<mutex> & __lk,chrono::time_point<chrono::steady_clock,chrono::nanoseconds> __tp)209 inline 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
232 template <class _Clock>
__do_timed_wait(unique_lock<mutex> & __lk,chrono::time_point<_Clock,chrono::nanoseconds> __tp)233 inline 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