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