1// <condition_variable> -*- C++ -*- 2 3// Copyright (C) 2008-2018 Free Software Foundation, Inc. 4// 5// This file is part of the GNU ISO C++ Library. This library is free 6// software; you can redistribute it and/or modify it under the 7// terms of the GNU General Public License as published by the 8// Free Software Foundation; either version 3, or (at your option) 9// any later version. 10 11// This library is distributed in the hope that it will be useful, 12// but WITHOUT ANY WARRANTY; without even the implied warranty of 13// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14// GNU General Public License for more details. 15 16// Under Section 7 of GPL version 3, you are granted additional 17// permissions described in the GCC Runtime Library Exception, version 18// 3.1, as published by the Free Software Foundation. 19 20// You should have received a copy of the GNU General Public License and 21// a copy of the GCC Runtime Library Exception along with this program; 22// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 23// <http://www.gnu.org/licenses/>. 24 25/** @file include/condition_variable 26 * This is a Standard C++ Library header. 27 */ 28 29#ifndef _GLIBCXX_CONDITION_VARIABLE 30#define _GLIBCXX_CONDITION_VARIABLE 1 31 32#pragma GCC system_header 33 34#if __cplusplus < 201103L 35# include <bits/c++0x_warning.h> 36#else 37 38#include <chrono> 39#include <bits/std_mutex.h> 40#include <ext/concurrence.h> 41#include <bits/alloc_traits.h> 42#include <bits/allocator.h> 43#include <bits/unique_ptr.h> 44#include <bits/shared_ptr.h> 45#include <bits/cxxabi_forced.h> 46 47#if defined(_GLIBCXX_HAS_GTHREADS) && defined(_GLIBCXX_USE_C99_STDINT_TR1) 48 49namespace std _GLIBCXX_VISIBILITY(default) 50{ 51_GLIBCXX_BEGIN_NAMESPACE_VERSION 52 53 /** 54 * @defgroup condition_variables Condition Variables 55 * @ingroup concurrency 56 * 57 * Classes for condition_variable support. 58 * @{ 59 */ 60 61 /// cv_status 62 enum class cv_status { no_timeout, timeout }; 63 64 /// condition_variable 65 class condition_variable 66 { 67 typedef chrono::system_clock __clock_t; 68 typedef __gthread_cond_t __native_type; 69 70#ifdef __GTHREAD_COND_INIT 71 __native_type _M_cond = __GTHREAD_COND_INIT; 72#else 73 __native_type _M_cond; 74#endif 75 76 public: 77 typedef __native_type* native_handle_type; 78 79 condition_variable() noexcept; 80 ~condition_variable() noexcept; 81 82 condition_variable(const condition_variable&) = delete; 83 condition_variable& operator=(const condition_variable&) = delete; 84 85 void 86 notify_one() noexcept; 87 88 void 89 notify_all() noexcept; 90 91 void 92 wait(unique_lock<mutex>& __lock) noexcept; 93 94 template<typename _Predicate> 95 void 96 wait(unique_lock<mutex>& __lock, _Predicate __p) 97 { 98 while (!__p()) 99 wait(__lock); 100 } 101 102 template<typename _Duration> 103 cv_status 104 wait_until(unique_lock<mutex>& __lock, 105 const chrono::time_point<__clock_t, _Duration>& __atime) 106 { return __wait_until_impl(__lock, __atime); } 107 108 template<typename _Clock, typename _Duration> 109 cv_status 110 wait_until(unique_lock<mutex>& __lock, 111 const chrono::time_point<_Clock, _Duration>& __atime) 112 { 113 // DR 887 - Sync unknown clock to known clock. 114 const typename _Clock::time_point __c_entry = _Clock::now(); 115 const __clock_t::time_point __s_entry = __clock_t::now(); 116 const auto __delta = __atime - __c_entry; 117 const auto __s_atime = __s_entry + __delta; 118 119 return __wait_until_impl(__lock, __s_atime); 120 } 121 122 template<typename _Clock, typename _Duration, typename _Predicate> 123 bool 124 wait_until(unique_lock<mutex>& __lock, 125 const chrono::time_point<_Clock, _Duration>& __atime, 126 _Predicate __p) 127 { 128 while (!__p()) 129 if (wait_until(__lock, __atime) == cv_status::timeout) 130 return __p(); 131 return true; 132 } 133 134 template<typename _Rep, typename _Period> 135 cv_status 136 wait_for(unique_lock<mutex>& __lock, 137 const chrono::duration<_Rep, _Period>& __rtime) 138 { 139 using __dur = typename __clock_t::duration; 140 auto __reltime = chrono::duration_cast<__dur>(__rtime); 141 if (__reltime < __rtime) 142 ++__reltime; 143 return wait_until(__lock, __clock_t::now() + __reltime); 144 } 145 146 template<typename _Rep, typename _Period, typename _Predicate> 147 bool 148 wait_for(unique_lock<mutex>& __lock, 149 const chrono::duration<_Rep, _Period>& __rtime, 150 _Predicate __p) 151 { 152 using __dur = typename __clock_t::duration; 153 auto __reltime = chrono::duration_cast<__dur>(__rtime); 154 if (__reltime < __rtime) 155 ++__reltime; 156 return wait_until(__lock, __clock_t::now() + __reltime, std::move(__p)); 157 } 158 159 native_handle_type 160 native_handle() 161 { return &_M_cond; } 162 163 private: 164 template<typename _Dur> 165 cv_status 166 __wait_until_impl(unique_lock<mutex>& __lock, 167 const chrono::time_point<__clock_t, _Dur>& __atime) 168 { 169 auto __s = chrono::time_point_cast<chrono::seconds>(__atime); 170 auto __ns = chrono::duration_cast<chrono::nanoseconds>(__atime - __s); 171 172 __gthread_time_t __ts = 173 { 174 static_cast<std::time_t>(__s.time_since_epoch().count()), 175 static_cast<long>(__ns.count()) 176 }; 177 178 __gthread_cond_timedwait(&_M_cond, __lock.mutex()->native_handle(), 179 &__ts); 180 181 return (__clock_t::now() < __atime 182 ? cv_status::no_timeout : cv_status::timeout); 183 } 184 }; 185 186 void 187 notify_all_at_thread_exit(condition_variable&, unique_lock<mutex>); 188 189 struct __at_thread_exit_elt 190 { 191 __at_thread_exit_elt* _M_next; 192 void (*_M_cb)(void*); 193 }; 194 195 inline namespace _V2 { 196 197 /// condition_variable_any 198 // Like above, but mutex is not required to have try_lock. 199 class condition_variable_any 200 { 201 typedef chrono::system_clock __clock_t; 202 condition_variable _M_cond; 203 shared_ptr<mutex> _M_mutex; 204 205 // scoped unlock - unlocks in ctor, re-locks in dtor 206 template<typename _Lock> 207 struct _Unlock 208 { 209 explicit _Unlock(_Lock& __lk) : _M_lock(__lk) { __lk.unlock(); } 210 211 ~_Unlock() noexcept(false) 212 { 213 if (uncaught_exception()) 214 { 215 __try 216 { _M_lock.lock(); } 217 __catch(const __cxxabiv1::__forced_unwind&) 218 { __throw_exception_again; } 219 __catch(...) 220 { } 221 } 222 else 223 _M_lock.lock(); 224 } 225 226 _Unlock(const _Unlock&) = delete; 227 _Unlock& operator=(const _Unlock&) = delete; 228 229 _Lock& _M_lock; 230 }; 231 232 public: 233 condition_variable_any() : _M_mutex(std::make_shared<mutex>()) { } 234 ~condition_variable_any() = default; 235 236 condition_variable_any(const condition_variable_any&) = delete; 237 condition_variable_any& operator=(const condition_variable_any&) = delete; 238 239 void 240 notify_one() noexcept 241 { 242 lock_guard<mutex> __lock(*_M_mutex); 243 _M_cond.notify_one(); 244 } 245 246 void 247 notify_all() noexcept 248 { 249 lock_guard<mutex> __lock(*_M_mutex); 250 _M_cond.notify_all(); 251 } 252 253 template<typename _Lock> 254 void 255 wait(_Lock& __lock) 256 { 257 shared_ptr<mutex> __mutex = _M_mutex; 258 unique_lock<mutex> __my_lock(*__mutex); 259 _Unlock<_Lock> __unlock(__lock); 260 // *__mutex must be unlocked before re-locking __lock so move 261 // ownership of *__mutex lock to an object with shorter lifetime. 262 unique_lock<mutex> __my_lock2(std::move(__my_lock)); 263 _M_cond.wait(__my_lock2); 264 } 265 266 267 template<typename _Lock, typename _Predicate> 268 void 269 wait(_Lock& __lock, _Predicate __p) 270 { 271 while (!__p()) 272 wait(__lock); 273 } 274 275 template<typename _Lock, typename _Clock, typename _Duration> 276 cv_status 277 wait_until(_Lock& __lock, 278 const chrono::time_point<_Clock, _Duration>& __atime) 279 { 280 shared_ptr<mutex> __mutex = _M_mutex; 281 unique_lock<mutex> __my_lock(*__mutex); 282 _Unlock<_Lock> __unlock(__lock); 283 // *__mutex must be unlocked before re-locking __lock so move 284 // ownership of *__mutex lock to an object with shorter lifetime. 285 unique_lock<mutex> __my_lock2(std::move(__my_lock)); 286 return _M_cond.wait_until(__my_lock2, __atime); 287 } 288 289 template<typename _Lock, typename _Clock, 290 typename _Duration, typename _Predicate> 291 bool 292 wait_until(_Lock& __lock, 293 const chrono::time_point<_Clock, _Duration>& __atime, 294 _Predicate __p) 295 { 296 while (!__p()) 297 if (wait_until(__lock, __atime) == cv_status::timeout) 298 return __p(); 299 return true; 300 } 301 302 template<typename _Lock, typename _Rep, typename _Period> 303 cv_status 304 wait_for(_Lock& __lock, const chrono::duration<_Rep, _Period>& __rtime) 305 { return wait_until(__lock, __clock_t::now() + __rtime); } 306 307 template<typename _Lock, typename _Rep, 308 typename _Period, typename _Predicate> 309 bool 310 wait_for(_Lock& __lock, 311 const chrono::duration<_Rep, _Period>& __rtime, _Predicate __p) 312 { return wait_until(__lock, __clock_t::now() + __rtime, std::move(__p)); } 313 }; 314 315 } // end inline namespace 316 317 // @} group condition_variables 318_GLIBCXX_END_NAMESPACE_VERSION 319} // namespace 320 321#endif // _GLIBCXX_HAS_GTHREADS && _GLIBCXX_USE_C99_STDINT_TR1 322 323#endif // C++11 324 325#endif // _GLIBCXX_CONDITION_VARIABLE 326