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 42 template <class _Rep, class _Period, __enable_if_t<is_floating_point<_Rep>::value, int> = 0> 43 inline _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 62 template <class _Rep, class _Period, __enable_if_t<!is_floating_point<_Rep>::value, int> = 0> 63 inline _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 89 class _LIBCPP_EXPORTED_FROM_ABI condition_variable { 90 __libcpp_condvar_t __cv_ = _LIBCPP_CONDVAR_INITIALIZER; 91 92 public: 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_; } 174 175 private: 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 189 190 template <class _Rep, class _Period, class _Predicate> 191 inline bool 192 condition_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 197 inline 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 219 220 template <class _Clock> 221 inline 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 233