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> 96 inline _LIBCPP_HIDE_FROM_ABI __enable_if_t<is_floating_point<_Rep>::value, chrono::nanoseconds> 97 __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> 117 inline _LIBCPP_HIDE_FROM_ABI __enable_if_t<!is_floating_point<_Rep>::value, chrono::nanoseconds> 118 __safe_nanosecond_cast(chrono::duration<_Rep, _Period> __d) { 119 using namespace chrono; 120 if (__d.count() == 0) { 121 return nanoseconds(0); 122 } 123 124 using __ratio = ratio_divide<_Period, nano>; 125 using __ns_rep = nanoseconds::rep; 126 __ns_rep __result_max = numeric_limits<__ns_rep>::max(); 127 if (__d.count() > 0 && __d.count() > __result_max / __ratio::num) { 128 return nanoseconds::max(); 129 } 130 131 __ns_rep __result_min = numeric_limits<__ns_rep>::min(); 132 if (__d.count() < 0 && __d.count() < __result_min / __ratio::num) { 133 return nanoseconds::min(); 134 } 135 136 __ns_rep __result = __d.count() * __ratio::num / __ratio::den; 137 if (__result == 0) { 138 return nanoseconds(1); 139 } 140 141 return nanoseconds(__result); 142 } 143 144 #ifndef _LIBCPP_HAS_NO_THREADS 145 template <class _Predicate> 146 void condition_variable::wait(unique_lock<mutex>& __lk, _Predicate __pred) { 147 while (!__pred()) 148 wait(__lk); 149 } 150 151 template <class _Clock, class _Duration> 152 cv_status condition_variable::wait_until(unique_lock<mutex>& __lk, const chrono::time_point<_Clock, _Duration>& __t) { 153 using namespace chrono; 154 using __clock_tp_ns = time_point<_Clock, nanoseconds>; 155 156 typename _Clock::time_point __now = _Clock::now(); 157 if (__t <= __now) 158 return cv_status::timeout; 159 160 __clock_tp_ns __t_ns = __clock_tp_ns(std::__safe_nanosecond_cast(__t.time_since_epoch())); 161 162 __do_timed_wait(__lk, __t_ns); 163 return _Clock::now() < __t ? cv_status::no_timeout : cv_status::timeout; 164 } 165 166 template <class _Clock, class _Duration, class _Predicate> 167 bool condition_variable::wait_until( 168 unique_lock<mutex>& __lk, const chrono::time_point<_Clock, _Duration>& __t, _Predicate __pred) { 169 while (!__pred()) { 170 if (wait_until(__lk, __t) == cv_status::timeout) 171 return __pred(); 172 } 173 return true; 174 } 175 176 template <class _Rep, class _Period> 177 cv_status condition_variable::wait_for(unique_lock<mutex>& __lk, const chrono::duration<_Rep, _Period>& __d) { 178 using namespace chrono; 179 if (__d <= __d.zero()) 180 return cv_status::timeout; 181 using __ns_rep = nanoseconds::rep; 182 steady_clock::time_point __c_now = steady_clock::now(); 183 184 # if defined(_LIBCPP_HAS_COND_CLOCKWAIT) 185 using __clock_tp_ns = time_point<steady_clock, nanoseconds>; 186 __ns_rep __now_count_ns = std::__safe_nanosecond_cast(__c_now.time_since_epoch()).count(); 187 # else 188 using __clock_tp_ns = time_point<system_clock, nanoseconds>; 189 __ns_rep __now_count_ns = std::__safe_nanosecond_cast(system_clock::now().time_since_epoch()).count(); 190 # endif 191 192 __ns_rep __d_ns_count = std::__safe_nanosecond_cast(__d).count(); 193 194 if (__now_count_ns > numeric_limits<__ns_rep>::max() - __d_ns_count) { 195 __do_timed_wait(__lk, __clock_tp_ns::max()); 196 } else { 197 __do_timed_wait(__lk, __clock_tp_ns(nanoseconds(__now_count_ns + __d_ns_count))); 198 } 199 200 return steady_clock::now() - __c_now < __d ? cv_status::no_timeout : cv_status::timeout; 201 } 202 203 template <class _Rep, class _Period, class _Predicate> 204 inline bool 205 condition_variable::wait_for(unique_lock<mutex>& __lk, const chrono::duration<_Rep, _Period>& __d, _Predicate __pred) { 206 return wait_until(__lk, chrono::steady_clock::now() + __d, std::move(__pred)); 207 } 208 209 # if defined(_LIBCPP_HAS_COND_CLOCKWAIT) 210 inline void condition_variable::__do_timed_wait( 211 unique_lock<mutex>& __lk, chrono::time_point<chrono::steady_clock, chrono::nanoseconds> __tp) _NOEXCEPT { 212 using namespace chrono; 213 if (!__lk.owns_lock()) 214 __throw_system_error(EPERM, "condition_variable::timed wait: mutex not locked"); 215 nanoseconds __d = __tp.time_since_epoch(); 216 timespec __ts; 217 seconds __s = duration_cast<seconds>(__d); 218 using __ts_sec = decltype(__ts.tv_sec); 219 const __ts_sec __ts_sec_max = numeric_limits<__ts_sec>::max(); 220 if (__s.count() < __ts_sec_max) { 221 __ts.tv_sec = static_cast<__ts_sec>(__s.count()); 222 __ts.tv_nsec = (__d - __s).count(); 223 } else { 224 __ts.tv_sec = __ts_sec_max; 225 __ts.tv_nsec = giga::num - 1; 226 } 227 int __ec = pthread_cond_clockwait(&__cv_, __lk.mutex()->native_handle(), CLOCK_MONOTONIC, &__ts); 228 if (__ec != 0 && __ec != ETIMEDOUT) 229 __throw_system_error(__ec, "condition_variable timed_wait failed"); 230 } 231 # endif // _LIBCPP_HAS_COND_CLOCKWAIT 232 233 template <class _Clock> 234 inline void condition_variable::__do_timed_wait(unique_lock<mutex>& __lk, 235 chrono::time_point<_Clock, chrono::nanoseconds> __tp) _NOEXCEPT { 236 wait_for(__lk, __tp - _Clock::now()); 237 } 238 239 #endif // _LIBCPP_HAS_NO_THREADS 240 241 _LIBCPP_END_NAMESPACE_STD 242 243 _LIBCPP_POP_MACROS 244 245 #endif // _LIBCPP___CONDITION_VARIABLE_CONDITION_VARIABLE_H 246