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 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> 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> 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> 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> 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> 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> 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 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) 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> 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