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 150class _LIBCPP_EXPORTED_FROM_ABI condition_variable_any { 151 condition_variable __cv_; 152 shared_ptr<mutex> __mut_; 153 154public: 155 _LIBCPP_HIDE_FROM_ABI condition_variable_any(); 156 157 _LIBCPP_HIDE_FROM_ABI void notify_one() _NOEXCEPT; 158 _LIBCPP_HIDE_FROM_ABI void notify_all() _NOEXCEPT; 159 160 template <class _Lock> 161 _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS void wait(_Lock& __lock); 162 template <class _Lock, class _Predicate> 163 _LIBCPP_HIDE_FROM_ABI void wait(_Lock& __lock, _Predicate __pred); 164 165 template <class _Lock, class _Clock, class _Duration> 166 _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS cv_status 167 wait_until(_Lock& __lock, const chrono::time_point<_Clock, _Duration>& __t); 168 169 template <class _Lock, class _Clock, class _Duration, class _Predicate> 170 bool _LIBCPP_HIDE_FROM_ABI 171 wait_until(_Lock& __lock, const chrono::time_point<_Clock, _Duration>& __t, _Predicate __pred); 172 173 template <class _Lock, class _Rep, class _Period> 174 cv_status _LIBCPP_HIDE_FROM_ABI wait_for(_Lock& __lock, const chrono::duration<_Rep, _Period>& __d); 175 176 template <class _Lock, class _Rep, class _Period, class _Predicate> 177 bool _LIBCPP_HIDE_FROM_ABI wait_for(_Lock& __lock, const chrono::duration<_Rep, _Period>& __d, _Predicate __pred); 178 179# if _LIBCPP_STD_VER >= 20 180 181 template <class _Lock, class _Predicate> 182 _LIBCPP_AVAILABILITY_SYNC _LIBCPP_HIDE_FROM_ABI bool wait(_Lock& __lock, stop_token __stoken, _Predicate __pred); 183 184 template <class _Lock, class _Clock, class _Duration, class _Predicate> 185 _LIBCPP_AVAILABILITY_SYNC _LIBCPP_HIDE_FROM_ABI bool wait_until( 186 _Lock& __lock, stop_token __stoken, const chrono::time_point<_Clock, _Duration>& __abs_time, _Predicate __pred); 187 188 template <class _Lock, class _Rep, class _Period, class _Predicate> 189 _LIBCPP_AVAILABILITY_SYNC _LIBCPP_HIDE_FROM_ABI bool 190 wait_for(_Lock& __lock, stop_token __stoken, const chrono::duration<_Rep, _Period>& __rel_time, _Predicate __pred); 191 192# endif // _LIBCPP_STD_VER >= 20 193}; 194 195inline condition_variable_any::condition_variable_any() : __mut_(make_shared<mutex>()) {} 196 197inline void condition_variable_any::notify_one() _NOEXCEPT { 198 { lock_guard<mutex> __lx(*__mut_); } 199 __cv_.notify_one(); 200} 201 202inline void condition_variable_any::notify_all() _NOEXCEPT { 203 { lock_guard<mutex> __lx(*__mut_); } 204 __cv_.notify_all(); 205} 206 207template <class _Lock> 208struct __unlock_guard { 209 _Lock& __lock_; 210 211 _LIBCPP_HIDE_FROM_ABI __unlock_guard(_Lock& __lock) : __lock_(__lock) { __lock_.unlock(); } 212 213 _LIBCPP_HIDE_FROM_ABI ~__unlock_guard() _NOEXCEPT // turns exception to std::terminate 214 { 215 __lock_.lock(); 216 } 217 218 __unlock_guard(const __unlock_guard&) = delete; 219 __unlock_guard& operator=(const __unlock_guard&) = delete; 220}; 221 222template <class _Lock> 223void condition_variable_any::wait(_Lock& __lock) { 224 shared_ptr<mutex> __mut = __mut_; 225 unique_lock<mutex> __lk(*__mut); 226 __unlock_guard<_Lock> __unlock(__lock); 227 lock_guard<unique_lock<mutex> > __lx(__lk, adopt_lock_t()); 228 __cv_.wait(__lk); 229} // __mut_.unlock(), __lock.lock() 230 231template <class _Lock, class _Predicate> 232inline void condition_variable_any::wait(_Lock& __lock, _Predicate __pred) { 233 while (!__pred()) 234 wait(__lock); 235} 236 237template <class _Lock, class _Clock, class _Duration> 238cv_status condition_variable_any::wait_until(_Lock& __lock, const chrono::time_point<_Clock, _Duration>& __t) { 239 shared_ptr<mutex> __mut = __mut_; 240 unique_lock<mutex> __lk(*__mut); 241 __unlock_guard<_Lock> __unlock(__lock); 242 lock_guard<unique_lock<mutex> > __lx(__lk, adopt_lock_t()); 243 return __cv_.wait_until(__lk, __t); 244} // __mut_.unlock(), __lock.lock() 245 246template <class _Lock, class _Clock, class _Duration, class _Predicate> 247inline bool 248condition_variable_any::wait_until(_Lock& __lock, const chrono::time_point<_Clock, _Duration>& __t, _Predicate __pred) { 249 while (!__pred()) 250 if (wait_until(__lock, __t) == cv_status::timeout) 251 return __pred(); 252 return true; 253} 254 255template <class _Lock, class _Rep, class _Period> 256inline cv_status condition_variable_any::wait_for(_Lock& __lock, const chrono::duration<_Rep, _Period>& __d) { 257 return wait_until(__lock, chrono::steady_clock::now() + __d); 258} 259 260template <class _Lock, class _Rep, class _Period, class _Predicate> 261inline bool 262condition_variable_any::wait_for(_Lock& __lock, const chrono::duration<_Rep, _Period>& __d, _Predicate __pred) { 263 return wait_until(__lock, chrono::steady_clock::now() + __d, std::move(__pred)); 264} 265 266# if _LIBCPP_STD_VER >= 20 267 268template <class _Lock, class _Predicate> 269bool condition_variable_any::wait(_Lock& __user_lock, stop_token __stoken, _Predicate __pred) { 270 if (__stoken.stop_requested()) 271 return __pred(); 272 273 // Per https://eel.is/c++draft/thread.condition.condvarany#general-note-2, 274 // we do need to take a copy of the shared pointer __mut_ 275 // This ensures that a thread can call the destructor immediately after calling 276 // notify_all, without waiting all the wait calls. 277 // A thread can also safely call the destructor immediately after calling 278 // request_stop, as the call to request_stop would evaluate the callback, 279 // which accesses the internal condition variable, immediately on the same thread. 280 // In this situation, it is OK even without copying a shared ownership the internal 281 // condition variable. However, this needs the evaluation of stop_callback to 282 // happen-before the destruction. 283 // The spec only says "Only the notification to unblock the wait needs to happen 284 // before destruction". To make this work, we need to copy the shared ownership of 285 // the internal condition variable inside this function, which is not possible 286 // with the current ABI. 287 shared_ptr<mutex> __mut = __mut_; 288 289 stop_callback __cb(__stoken, [this] { notify_all(); }); 290 291 while (true) { 292 if (__pred()) 293 return true; 294 295 // We need to take the internal lock before checking stop_requested, 296 // so that the notification cannot come in between the stop_requested 297 // check and entering the wait. 298 // Note that the stop_callback takes the same internal lock before notifying 299 unique_lock<mutex> __internal_lock(*__mut); 300 if (__stoken.stop_requested()) 301 break; 302 303 __unlock_guard<_Lock> __unlock(__user_lock); 304 unique_lock<mutex> __internal_lock2( 305 std::move(__internal_lock)); // switch unlock order between __internal_lock and __user_lock 306 __cv_.wait(__internal_lock2); 307 } // __internal_lock2.unlock(), __user_lock.lock() 308 return __pred(); 309} 310 311template <class _Lock, class _Clock, class _Duration, class _Predicate> 312bool condition_variable_any::wait_until( 313 _Lock& __user_lock, 314 stop_token __stoken, 315 const chrono::time_point<_Clock, _Duration>& __abs_time, 316 _Predicate __pred) { 317 if (__stoken.stop_requested()) 318 return __pred(); 319 320 shared_ptr<mutex> __mut = __mut_; 321 stop_callback __cb(__stoken, [this] { notify_all(); }); 322 323 while (true) { 324 if (__pred()) 325 return true; 326 327 unique_lock<mutex> __internal_lock(*__mut); 328 if (__stoken.stop_requested()) 329 break; 330 331 __unlock_guard<_Lock> __unlock(__user_lock); 332 unique_lock<mutex> __internal_lock2( 333 std::move(__internal_lock)); // switch unlock order between __internal_lock and __user_lock 334 335 if (__cv_.wait_until(__internal_lock2, __abs_time) == cv_status::timeout) 336 break; 337 } // __internal_lock2.unlock(), __user_lock.lock() 338 return __pred(); 339} 340 341template <class _Lock, class _Rep, class _Period, class _Predicate> 342bool condition_variable_any::wait_for( 343 _Lock& __lock, stop_token __stoken, const chrono::duration<_Rep, _Period>& __rel_time, _Predicate __pred) { 344 return wait_until(__lock, std::move(__stoken), chrono::steady_clock::now() + __rel_time, std::move(__pred)); 345} 346 347# endif // _LIBCPP_STD_VER >= 20 348 349_LIBCPP_EXPORTED_FROM_ABI void notify_all_at_thread_exit(condition_variable&, unique_lock<mutex>); 350 351_LIBCPP_END_NAMESPACE_STD 352 353# endif // _LIBCPP_HAS_THREADS 354 355_LIBCPP_POP_MACROS 356 357# if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER <= 20 358# include <atomic> 359# include <concepts> 360# include <cstdint> 361# include <cstdlib> 362# include <cstring> 363# include <initializer_list> 364# include <iosfwd> 365# include <new> 366# include <stdexcept> 367# include <system_error> 368# include <type_traits> 369# include <typeinfo> 370# endif 371#endif // __cplusplus < 201103L && defined(_LIBCPP_USE_FROZEN_CXX03_HEADERS) 372 373#endif // _LIBCPP_CONDITION_VARIABLE 374