1// -*- C++ -*- 2//===----------------------------------------------------------------------===// 3// 4// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 5// See https://llvm.org/LICENSE.txt for license information. 6// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 7// 8//===----------------------------------------------------------------------===// 9 10#ifndef _LIBCPP_CONDITION_VARIABLE 11#define _LIBCPP_CONDITION_VARIABLE 12 13/* 14 condition_variable synopsis 15 16namespace std 17{ 18 19enum class cv_status { no_timeout, timeout }; 20 21class condition_variable 22{ 23public: 24 condition_variable(); 25 ~condition_variable(); 26 27 condition_variable(const condition_variable&) = delete; 28 condition_variable& operator=(const condition_variable&) = delete; 29 30 void notify_one() noexcept; 31 void notify_all() noexcept; 32 33 void wait(unique_lock<mutex>& lock); 34 template <class Predicate> 35 void wait(unique_lock<mutex>& lock, Predicate pred); 36 37 template <class Clock, class Duration> 38 cv_status 39 wait_until(unique_lock<mutex>& lock, 40 const chrono::time_point<Clock, Duration>& abs_time); 41 42 template <class Clock, class Duration, class Predicate> 43 bool 44 wait_until(unique_lock<mutex>& lock, 45 const chrono::time_point<Clock, Duration>& abs_time, 46 Predicate pred); 47 48 template <class Rep, class Period> 49 cv_status 50 wait_for(unique_lock<mutex>& lock, 51 const chrono::duration<Rep, Period>& rel_time); 52 53 template <class Rep, class Period, class Predicate> 54 bool 55 wait_for(unique_lock<mutex>& lock, 56 const chrono::duration<Rep, Period>& rel_time, 57 Predicate pred); 58 59 typedef pthread_cond_t* native_handle_type; 60 native_handle_type native_handle(); 61}; 62 63void notify_all_at_thread_exit(condition_variable& cond, unique_lock<mutex> lk); 64 65class condition_variable_any 66{ 67public: 68 condition_variable_any(); 69 ~condition_variable_any(); 70 71 condition_variable_any(const condition_variable_any&) = delete; 72 condition_variable_any& operator=(const condition_variable_any&) = delete; 73 74 void notify_one() noexcept; 75 void notify_all() noexcept; 76 77 template <class Lock> 78 void wait(Lock& lock); 79 template <class Lock, class Predicate> 80 void wait(Lock& lock, Predicate pred); 81 82 template <class Lock, class Clock, class Duration> 83 cv_status 84 wait_until(Lock& lock, 85 const chrono::time_point<Clock, Duration>& abs_time); 86 87 template <class Lock, class Clock, class Duration, class Predicate> 88 bool 89 wait_until(Lock& lock, 90 const chrono::time_point<Clock, Duration>& abs_time, 91 Predicate pred); 92 93 template <class Lock, class Rep, class Period> 94 cv_status 95 wait_for(Lock& lock, 96 const chrono::duration<Rep, Period>& rel_time); 97 98 template <class Lock, class Rep, class Period, class Predicate> 99 bool 100 wait_for(Lock& lock, 101 const chrono::duration<Rep, Period>& rel_time, 102 Predicate pred); 103 104 // [thread.condvarany.intwait], interruptible waits 105 template <class Lock, class Predicate> 106 bool wait(Lock& lock, stop_token stoken, Predicate pred); // since C++20 107 108 template <class Lock, class Clock, class Duration, class Predicate> 109 bool wait_until(Lock& lock, stop_token stoken, 110 const chrono::time_point<Clock, Duration>& abs_time, Predicate pred); // since C++20 111 112 template <class Lock, class Rep, class Period, class Predicate> 113 bool wait_for(Lock& lock, stop_token stoken, 114 const chrono::duration<Rep, Period>& rel_time, Predicate pred); // since C++20 115}; 116 117} // std 118 119*/ 120 121#include <__chrono/duration.h> 122#include <__chrono/steady_clock.h> 123#include <__chrono/time_point.h> 124#include <__condition_variable/condition_variable.h> 125#include <__config> 126#include <__memory/shared_ptr.h> 127#include <__mutex/lock_guard.h> 128#include <__mutex/mutex.h> 129#include <__mutex/tag_types.h> 130#include <__mutex/unique_lock.h> 131#include <__stop_token/stop_callback.h> 132#include <__stop_token/stop_token.h> 133#include <__utility/move.h> 134#include <version> 135 136#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 137# pragma GCC system_header 138#endif 139 140_LIBCPP_PUSH_MACROS 141#include <__undef_macros> 142 143#ifndef _LIBCPP_HAS_NO_THREADS 144 145_LIBCPP_BEGIN_NAMESPACE_STD 146 147class _LIBCPP_EXPORTED_FROM_ABI condition_variable_any { 148 condition_variable __cv_; 149 shared_ptr<mutex> __mut_; 150 151public: 152 _LIBCPP_HIDE_FROM_ABI condition_variable_any(); 153 154 _LIBCPP_HIDE_FROM_ABI void notify_one() _NOEXCEPT; 155 _LIBCPP_HIDE_FROM_ABI void notify_all() _NOEXCEPT; 156 157 template <class _Lock> 158 _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS void wait(_Lock& __lock); 159 template <class _Lock, class _Predicate> 160 _LIBCPP_HIDE_FROM_ABI void wait(_Lock& __lock, _Predicate __pred); 161 162 template <class _Lock, class _Clock, class _Duration> 163 _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS cv_status 164 wait_until(_Lock& __lock, const chrono::time_point<_Clock, _Duration>& __t); 165 166 template <class _Lock, class _Clock, class _Duration, class _Predicate> 167 bool _LIBCPP_HIDE_FROM_ABI 168 wait_until(_Lock& __lock, const chrono::time_point<_Clock, _Duration>& __t, _Predicate __pred); 169 170 template <class _Lock, class _Rep, class _Period> 171 cv_status _LIBCPP_HIDE_FROM_ABI wait_for(_Lock& __lock, const chrono::duration<_Rep, _Period>& __d); 172 173 template <class _Lock, class _Rep, class _Period, class _Predicate> 174 bool _LIBCPP_HIDE_FROM_ABI wait_for(_Lock& __lock, const chrono::duration<_Rep, _Period>& __d, _Predicate __pred); 175 176# if _LIBCPP_STD_VER >= 20 && !defined(_LIBCPP_HAS_NO_EXPERIMENTAL_STOP_TOKEN) 177 178 template <class _Lock, class _Predicate> 179 _LIBCPP_AVAILABILITY_SYNC _LIBCPP_HIDE_FROM_ABI bool wait(_Lock& __lock, stop_token __stoken, _Predicate __pred); 180 181 template <class _Lock, class _Clock, class _Duration, class _Predicate> 182 _LIBCPP_AVAILABILITY_SYNC _LIBCPP_HIDE_FROM_ABI bool wait_until( 183 _Lock& __lock, stop_token __stoken, const chrono::time_point<_Clock, _Duration>& __abs_time, _Predicate __pred); 184 185 template <class _Lock, class _Rep, class _Period, class _Predicate> 186 _LIBCPP_AVAILABILITY_SYNC _LIBCPP_HIDE_FROM_ABI bool 187 wait_for(_Lock& __lock, stop_token __stoken, const chrono::duration<_Rep, _Period>& __rel_time, _Predicate __pred); 188 189# endif // _LIBCPP_STD_VER >= 20 && !defined(_LIBCPP_HAS_NO_EXPERIMENTAL_STOP_TOKEN) 190}; 191 192inline condition_variable_any::condition_variable_any() : __mut_(make_shared<mutex>()) {} 193 194inline void condition_variable_any::notify_one() _NOEXCEPT { 195 { lock_guard<mutex> __lx(*__mut_); } 196 __cv_.notify_one(); 197} 198 199inline void condition_variable_any::notify_all() _NOEXCEPT { 200 { lock_guard<mutex> __lx(*__mut_); } 201 __cv_.notify_all(); 202} 203 204template <class _Lock> 205struct __unlock_guard { 206 _Lock& __lock_; 207 208 _LIBCPP_HIDE_FROM_ABI __unlock_guard(_Lock& __lock) : __lock_(__lock) { __lock_.unlock(); } 209 210 _LIBCPP_HIDE_FROM_ABI ~__unlock_guard() _NOEXCEPT // turns exception to std::terminate 211 { 212 __lock_.lock(); 213 } 214 215 __unlock_guard(const __unlock_guard&) = delete; 216 __unlock_guard& operator=(const __unlock_guard&) = delete; 217}; 218 219template <class _Lock> 220void condition_variable_any::wait(_Lock& __lock) { 221 shared_ptr<mutex> __mut = __mut_; 222 unique_lock<mutex> __lk(*__mut); 223 __unlock_guard<_Lock> __unlock(__lock); 224 lock_guard<unique_lock<mutex> > __lx(__lk, adopt_lock_t()); 225 __cv_.wait(__lk); 226} // __mut_.unlock(), __lock.lock() 227 228template <class _Lock, class _Predicate> 229inline void condition_variable_any::wait(_Lock& __lock, _Predicate __pred) { 230 while (!__pred()) 231 wait(__lock); 232} 233 234template <class _Lock, class _Clock, class _Duration> 235cv_status condition_variable_any::wait_until(_Lock& __lock, const chrono::time_point<_Clock, _Duration>& __t) { 236 shared_ptr<mutex> __mut = __mut_; 237 unique_lock<mutex> __lk(*__mut); 238 __unlock_guard<_Lock> __unlock(__lock); 239 lock_guard<unique_lock<mutex> > __lx(__lk, adopt_lock_t()); 240 return __cv_.wait_until(__lk, __t); 241} // __mut_.unlock(), __lock.lock() 242 243template <class _Lock, class _Clock, class _Duration, class _Predicate> 244inline bool 245condition_variable_any::wait_until(_Lock& __lock, const chrono::time_point<_Clock, _Duration>& __t, _Predicate __pred) { 246 while (!__pred()) 247 if (wait_until(__lock, __t) == cv_status::timeout) 248 return __pred(); 249 return true; 250} 251 252template <class _Lock, class _Rep, class _Period> 253inline cv_status condition_variable_any::wait_for(_Lock& __lock, const chrono::duration<_Rep, _Period>& __d) { 254 return wait_until(__lock, chrono::steady_clock::now() + __d); 255} 256 257template <class _Lock, class _Rep, class _Period, class _Predicate> 258inline bool 259condition_variable_any::wait_for(_Lock& __lock, const chrono::duration<_Rep, _Period>& __d, _Predicate __pred) { 260 return wait_until(__lock, chrono::steady_clock::now() + __d, std::move(__pred)); 261} 262 263# if _LIBCPP_STD_VER >= 20 && !defined(_LIBCPP_HAS_NO_EXPERIMENTAL_STOP_TOKEN) 264 265template <class _Lock, class _Predicate> 266bool condition_variable_any::wait(_Lock& __user_lock, stop_token __stoken, _Predicate __pred) { 267 if (__stoken.stop_requested()) 268 return __pred(); 269 270 // Per https://eel.is/c++draft/thread.condition.condvarany#general-note-2, 271 // we do need to take a copy of the shared pointer __mut_ 272 // This ensures that a thread can call the destructor immediately after calling 273 // notify_all, without waiting all the wait calls. 274 // A thread can also safely call the destructor immediately after calling 275 // request_stop, as the call to request_stop would evaluate the callback, 276 // which accesses the internal condition variable, immediately on the same thread. 277 // In this situation, it is OK even without copying a shared ownership the internal 278 // condition variable. However, this needs the evaluation of stop_callback to 279 // happen-before the destruction. 280 // The spec only says "Only the notification to unblock the wait needs to happen 281 // before destruction". To make this work, we need to copy the shared ownership of 282 // the internal condition variable inside this function, which is not possible 283 // with the current ABI. 284 shared_ptr<mutex> __mut = __mut_; 285 286 stop_callback __cb(__stoken, [this] { notify_all(); }); 287 288 while (true) { 289 if (__pred()) 290 return true; 291 292 // We need to take the internal lock before checking stop_requested, 293 // so that the notification cannot come in between the stop_requested 294 // check and entering the wait. 295 // Note that the stop_callback takes the same internal lock before notifying 296 unique_lock<mutex> __internal_lock(*__mut); 297 if (__stoken.stop_requested()) 298 break; 299 300 __unlock_guard<_Lock> __unlock(__user_lock); 301 unique_lock<mutex> __internal_lock2( 302 std::move(__internal_lock)); // switch unlock order between __internal_lock and __user_lock 303 __cv_.wait(__internal_lock2); 304 } // __internal_lock2.unlock(), __user_lock.lock() 305 return __pred(); 306} 307 308template <class _Lock, class _Clock, class _Duration, class _Predicate> 309bool condition_variable_any::wait_until( 310 _Lock& __user_lock, 311 stop_token __stoken, 312 const chrono::time_point<_Clock, _Duration>& __abs_time, 313 _Predicate __pred) { 314 if (__stoken.stop_requested()) 315 return __pred(); 316 317 shared_ptr<mutex> __mut = __mut_; 318 stop_callback __cb(__stoken, [this] { notify_all(); }); 319 320 while (true) { 321 if (__pred()) 322 return true; 323 324 unique_lock<mutex> __internal_lock(*__mut); 325 if (__stoken.stop_requested()) 326 break; 327 328 __unlock_guard<_Lock> __unlock(__user_lock); 329 unique_lock<mutex> __internal_lock2( 330 std::move(__internal_lock)); // switch unlock order between __internal_lock and __user_lock 331 332 if (__cv_.wait_until(__internal_lock2, __abs_time) == cv_status::timeout) 333 break; 334 } // __internal_lock2.unlock(), __user_lock.lock() 335 return __pred(); 336} 337 338template <class _Lock, class _Rep, class _Period, class _Predicate> 339bool condition_variable_any::wait_for( 340 _Lock& __lock, stop_token __stoken, const chrono::duration<_Rep, _Period>& __rel_time, _Predicate __pred) { 341 return wait_until(__lock, std::move(__stoken), chrono::steady_clock::now() + __rel_time, std::move(__pred)); 342} 343 344# endif // _LIBCPP_STD_VER >= 20 && !defined(_LIBCPP_HAS_NO_EXPERIMENTAL_STOP_TOKEN) 345 346_LIBCPP_EXPORTED_FROM_ABI void notify_all_at_thread_exit(condition_variable&, unique_lock<mutex>); 347 348_LIBCPP_END_NAMESPACE_STD 349 350#endif // !_LIBCPP_HAS_NO_THREADS 351 352_LIBCPP_POP_MACROS 353 354#if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER <= 20 355# include <atomic> 356# include <concepts> 357# include <cstdint> 358# include <cstdlib> 359# include <cstring> 360# include <initializer_list> 361# include <iosfwd> 362# include <new> 363# include <stdexcept> 364# include <system_error> 365# include <type_traits> 366# include <typeinfo> 367#endif 368 369#endif // _LIBCPP_CONDITION_VARIABLE 370