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#if __cplusplus < 201103L && defined(_LIBCPP_USE_FROZEN_CXX03_HEADERS) 122# include <__cxx03/condition_variable> 123#else 124# include <__chrono/duration.h> 125# include <__chrono/steady_clock.h> 126# include <__chrono/time_point.h> 127# include <__condition_variable/condition_variable.h> 128# include <__config> 129# include <__memory/shared_ptr.h> 130# include <__mutex/lock_guard.h> 131# include <__mutex/mutex.h> 132# include <__mutex/tag_types.h> 133# include <__mutex/unique_lock.h> 134# include <__stop_token/stop_callback.h> 135# include <__stop_token/stop_token.h> 136# include <__utility/move.h> 137# include <version> 138 139# if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 140# pragma GCC system_header 141# endif 142 143_LIBCPP_PUSH_MACROS 144# include <__undef_macros> 145 146# if _LIBCPP_HAS_THREADS 147 148_LIBCPP_BEGIN_NAMESPACE_STD 149 150template <class _Lock> 151struct __unlock_guard { 152 _Lock& __lock_; 153 154 _LIBCPP_HIDE_FROM_ABI __unlock_guard(_Lock& __lock) : __lock_(__lock) { __lock_.unlock(); } 155 156 _LIBCPP_HIDE_FROM_ABI ~__unlock_guard() _NOEXCEPT // turns exception to std::terminate 157 { 158 __lock_.lock(); 159 } 160 161 __unlock_guard(const __unlock_guard&) = delete; 162 __unlock_guard& operator=(const __unlock_guard&) = delete; 163}; 164 165class _LIBCPP_EXPORTED_FROM_ABI condition_variable_any { 166 condition_variable __cv_; 167 shared_ptr<mutex> __mut_; 168 169public: 170 _LIBCPP_HIDE_FROM_ABI condition_variable_any(); 171 172 _LIBCPP_HIDE_FROM_ABI void notify_one() _NOEXCEPT; 173 _LIBCPP_HIDE_FROM_ABI void notify_all() _NOEXCEPT; 174 175 template <class _Lock> 176 _LIBCPP_HIDE_FROM_ABI void wait(_Lock& __lock) { 177 shared_ptr<mutex> __mut = __mut_; 178 unique_lock<mutex> __lk(*__mut); 179 __unlock_guard<_Lock> __unlock(__lock); 180 lock_guard<unique_lock<mutex> > __lx(__lk, adopt_lock_t()); 181 __cv_.wait(__lk); 182 } // __mut_.unlock(), __lock.lock() 183 184 template <class _Lock, class _Predicate> 185 _LIBCPP_HIDE_FROM_ABI void wait(_Lock& __lock, _Predicate __pred); 186 187 template <class _Lock, class _Clock, class _Duration> 188 _LIBCPP_HIDE_FROM_ABI cv_status wait_until(_Lock& __lock, const chrono::time_point<_Clock, _Duration>& __t) { 189 shared_ptr<mutex> __mut = __mut_; 190 unique_lock<mutex> __lk(*__mut); 191 __unlock_guard<_Lock> __unlock(__lock); 192 lock_guard<unique_lock<mutex> > __lx(__lk, adopt_lock_t()); 193 return __cv_.wait_until(__lk, __t); 194 } // __mut_.unlock(), __lock.lock() 195 196 template <class _Lock, class _Clock, class _Duration, class _Predicate> 197 bool _LIBCPP_HIDE_FROM_ABI 198 wait_until(_Lock& __lock, const chrono::time_point<_Clock, _Duration>& __t, _Predicate __pred); 199 200 template <class _Lock, class _Rep, class _Period> 201 cv_status _LIBCPP_HIDE_FROM_ABI wait_for(_Lock& __lock, const chrono::duration<_Rep, _Period>& __d); 202 203 template <class _Lock, class _Rep, class _Period, class _Predicate> 204 bool _LIBCPP_HIDE_FROM_ABI wait_for(_Lock& __lock, const chrono::duration<_Rep, _Period>& __d, _Predicate __pred); 205 206# if _LIBCPP_STD_VER >= 20 207 208 template <class _Lock, class _Predicate> 209 _LIBCPP_AVAILABILITY_SYNC _LIBCPP_HIDE_FROM_ABI bool wait(_Lock& __lock, stop_token __stoken, _Predicate __pred); 210 211 template <class _Lock, class _Clock, class _Duration, class _Predicate> 212 _LIBCPP_AVAILABILITY_SYNC _LIBCPP_HIDE_FROM_ABI bool wait_until( 213 _Lock& __lock, stop_token __stoken, const chrono::time_point<_Clock, _Duration>& __abs_time, _Predicate __pred); 214 215 template <class _Lock, class _Rep, class _Period, class _Predicate> 216 _LIBCPP_AVAILABILITY_SYNC _LIBCPP_HIDE_FROM_ABI bool 217 wait_for(_Lock& __lock, stop_token __stoken, const chrono::duration<_Rep, _Period>& __rel_time, _Predicate __pred); 218 219# endif // _LIBCPP_STD_VER >= 20 220}; 221 222inline condition_variable_any::condition_variable_any() : __mut_(make_shared<mutex>()) {} 223 224inline void condition_variable_any::notify_one() _NOEXCEPT { 225 { lock_guard<mutex> __lx(*__mut_); } 226 __cv_.notify_one(); 227} 228 229inline void condition_variable_any::notify_all() _NOEXCEPT { 230 { lock_guard<mutex> __lx(*__mut_); } 231 __cv_.notify_all(); 232} 233 234template <class _Lock, class _Predicate> 235inline void condition_variable_any::wait(_Lock& __lock, _Predicate __pred) { 236 while (!__pred()) 237 wait(__lock); 238} 239 240template <class _Lock, class _Clock, class _Duration, class _Predicate> 241inline bool 242condition_variable_any::wait_until(_Lock& __lock, const chrono::time_point<_Clock, _Duration>& __t, _Predicate __pred) { 243 while (!__pred()) 244 if (wait_until(__lock, __t) == cv_status::timeout) 245 return __pred(); 246 return true; 247} 248 249template <class _Lock, class _Rep, class _Period> 250inline cv_status condition_variable_any::wait_for(_Lock& __lock, const chrono::duration<_Rep, _Period>& __d) { 251 return wait_until(__lock, chrono::steady_clock::now() + __d); 252} 253 254template <class _Lock, class _Rep, class _Period, class _Predicate> 255inline bool 256condition_variable_any::wait_for(_Lock& __lock, const chrono::duration<_Rep, _Period>& __d, _Predicate __pred) { 257 return wait_until(__lock, chrono::steady_clock::now() + __d, std::move(__pred)); 258} 259 260# if _LIBCPP_STD_VER >= 20 261 262template <class _Lock, class _Predicate> 263bool condition_variable_any::wait(_Lock& __user_lock, stop_token __stoken, _Predicate __pred) { 264 if (__stoken.stop_requested()) 265 return __pred(); 266 267 // Per https://eel.is/c++draft/thread.condition.condvarany#general-note-2, 268 // we do need to take a copy of the shared pointer __mut_ 269 // This ensures that a thread can call the destructor immediately after calling 270 // notify_all, without waiting all the wait calls. 271 // A thread can also safely call the destructor immediately after calling 272 // request_stop, as the call to request_stop would evaluate the callback, 273 // which accesses the internal condition variable, immediately on the same thread. 274 // In this situation, it is OK even without copying a shared ownership the internal 275 // condition variable. However, this needs the evaluation of stop_callback to 276 // happen-before the destruction. 277 // The spec only says "Only the notification to unblock the wait needs to happen 278 // before destruction". To make this work, we need to copy the shared ownership of 279 // the internal condition variable inside this function, which is not possible 280 // with the current ABI. 281 shared_ptr<mutex> __mut = __mut_; 282 283 stop_callback __cb(__stoken, [this] { notify_all(); }); 284 285 while (true) { 286 if (__pred()) 287 return true; 288 289 // We need to take the internal lock before checking stop_requested, 290 // so that the notification cannot come in between the stop_requested 291 // check and entering the wait. 292 // Note that the stop_callback takes the same internal lock before notifying 293 unique_lock<mutex> __internal_lock(*__mut); 294 if (__stoken.stop_requested()) 295 break; 296 297 __unlock_guard<_Lock> __unlock(__user_lock); 298 unique_lock<mutex> __internal_lock2( 299 std::move(__internal_lock)); // switch unlock order between __internal_lock and __user_lock 300 __cv_.wait(__internal_lock2); 301 } // __internal_lock2.unlock(), __user_lock.lock() 302 return __pred(); 303} 304 305template <class _Lock, class _Clock, class _Duration, class _Predicate> 306bool condition_variable_any::wait_until( 307 _Lock& __user_lock, 308 stop_token __stoken, 309 const chrono::time_point<_Clock, _Duration>& __abs_time, 310 _Predicate __pred) { 311 if (__stoken.stop_requested()) 312 return __pred(); 313 314 shared_ptr<mutex> __mut = __mut_; 315 stop_callback __cb(__stoken, [this] { notify_all(); }); 316 317 while (true) { 318 if (__pred()) 319 return true; 320 321 unique_lock<mutex> __internal_lock(*__mut); 322 if (__stoken.stop_requested()) 323 break; 324 325 __unlock_guard<_Lock> __unlock(__user_lock); 326 unique_lock<mutex> __internal_lock2( 327 std::move(__internal_lock)); // switch unlock order between __internal_lock and __user_lock 328 329 if (__cv_.wait_until(__internal_lock2, __abs_time) == cv_status::timeout) 330 break; 331 } // __internal_lock2.unlock(), __user_lock.lock() 332 return __pred(); 333} 334 335template <class _Lock, class _Rep, class _Period, class _Predicate> 336bool condition_variable_any::wait_for( 337 _Lock& __lock, stop_token __stoken, const chrono::duration<_Rep, _Period>& __rel_time, _Predicate __pred) { 338 return wait_until(__lock, std::move(__stoken), chrono::steady_clock::now() + __rel_time, std::move(__pred)); 339} 340 341# endif // _LIBCPP_STD_VER >= 20 342 343_LIBCPP_EXPORTED_FROM_ABI void notify_all_at_thread_exit(condition_variable&, unique_lock<mutex>); 344 345_LIBCPP_END_NAMESPACE_STD 346 347# endif // _LIBCPP_HAS_THREADS 348 349_LIBCPP_POP_MACROS 350 351# if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER <= 20 352# include <atomic> 353# include <concepts> 354# include <cstdint> 355# include <cstdlib> 356# include <cstring> 357# include <initializer_list> 358# include <iosfwd> 359# include <new> 360# include <optional> 361# include <stdexcept> 362# include <system_error> 363# include <type_traits> 364# include <typeinfo> 365# endif 366#endif // __cplusplus < 201103L && defined(_LIBCPP_USE_FROZEN_CXX03_HEADERS) 367 368#endif // _LIBCPP_CONDITION_VARIABLE 369