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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-exception6//7//===----------------------------------------------------------------------===//8 9#ifndef _LIBCPP___CONDITION_VARIABLE_CONDITION_VARIABLE_H10#define _LIBCPP___CONDITION_VARIABLE_CONDITION_VARIABLE_H11 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_header29#endif30 31_LIBCPP_PUSH_MACROS32#include <__undef_macros>33 34_LIBCPP_BEGIN_NAMESPACE_STD35 36#if _LIBCPP_HAS_THREADS37 38// enum class cv_status39_LIBCPP_DECLARE_STRONG_ENUM(cv_status){no_timeout, timeout};40_LIBCPP_DECLARE_STRONG_ENUM_EPILOG(cv_status)41 42template <class _Rep, class _Period, __enable_if_t<is_floating_point<_Rep>::value, int> = 0>43inline _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 62template <class _Rep, class _Period, __enable_if_t<!is_floating_point<_Rep>::value, int> = 0>63inline _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 89class _LIBCPP_EXPORTED_FROM_ABI condition_variable {90 __libcpp_condvar_t __cv_ = _LIBCPP_CONDVAR_INITIALIZER;91 92public:93 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR condition_variable() _NOEXCEPT = default;94 95# if _LIBCPP_HAS_TRIVIAL_CONDVAR_DESTRUCTION96 ~condition_variable() = default;97# else98 ~condition_variable();99# endif100 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_status117 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 bool133 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_CLOCKWAIT150 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# else153 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# endif156 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_ABI170 wait_for(unique_lock<mutex>& __lk, const chrono::duration<_Rep, _Period>& __d, _Predicate __pred);171 172 typedef __libcpp_condvar_t* native_handle_type;173 [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI native_handle_type native_handle() { return &__cv_; }174 175private:176 void177 __do_timed_wait(unique_lock<mutex>& __lk, chrono::time_point<chrono::system_clock, chrono::nanoseconds>) _NOEXCEPT;178# if _LIBCPP_HAS_COND_CLOCKWAIT179 _LIBCPP_HIDE_FROM_ABI void180 __do_timed_wait(unique_lock<mutex>& __lk, chrono::time_point<chrono::steady_clock, chrono::nanoseconds>) _NOEXCEPT;181# endif182 template <class _Clock>183 _LIBCPP_HIDE_FROM_ABI void184 __do_timed_wait(unique_lock<mutex>& __lk, chrono::time_point<_Clock, chrono::nanoseconds>) _NOEXCEPT;185};186#endif // _LIBCPP_HAS_THREADS187 188#if _LIBCPP_HAS_THREADS189 190template <class _Rep, class _Period, class _Predicate>191inline bool192condition_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_CLOCKWAIT197inline 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_CLOCKWAIT219 220template <class _Clock>221inline 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_THREADS227 228_LIBCPP_END_NAMESPACE_STD229 230_LIBCPP_POP_MACROS231 232#endif // _LIBCPP___CONDITION_VARIABLE_CONDITION_VARIABLE_H233