1 // <condition_variable> -*- C++ -*- 2 3 // Copyright (C) 2008-2013 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 <mutex> // unique_lock 40 41 #if defined(_GLIBCXX_HAS_GTHREADS) && defined(_GLIBCXX_USE_C99_STDINT_TR1) 42 43 namespace std _GLIBCXX_VISIBILITY(default) 44 { 45 _GLIBCXX_BEGIN_NAMESPACE_VERSION 46 47 /** 48 * @defgroup condition_variables Condition Variables 49 * @ingroup concurrency 50 * 51 * Classes for condition_variable support. 52 * @{ 53 */ 54 55 /// cv_status 56 enum class cv_status { no_timeout, timeout }; 57 58 /// condition_variable 59 class condition_variable 60 { 61 typedef chrono::system_clock __clock_t; 62 typedef __gthread_cond_t __native_type; 63 64 #ifdef __GTHREAD_COND_INIT 65 __native_type _M_cond = __GTHREAD_COND_INIT; 66 #else 67 __native_type _M_cond; 68 #endif 69 70 public: 71 typedef __native_type* native_handle_type; 72 73 condition_variable() noexcept; 74 ~condition_variable() noexcept; 75 76 condition_variable(const condition_variable&) = delete; 77 condition_variable& operator=(const condition_variable&) = delete; 78 79 void 80 notify_one() noexcept; 81 82 void 83 notify_all() noexcept; 84 85 void 86 wait(unique_lock<mutex>& __lock); 87 88 template<typename _Predicate> 89 void 90 wait(unique_lock<mutex>& __lock, _Predicate __p) 91 { 92 while (!__p()) 93 wait(__lock); 94 } 95 96 template<typename _Duration> 97 cv_status 98 wait_until(unique_lock<mutex>& __lock, 99 const chrono::time_point<__clock_t, _Duration>& __atime) 100 { return __wait_until_impl(__lock, __atime); } 101 102 template<typename _Clock, typename _Duration> 103 cv_status 104 wait_until(unique_lock<mutex>& __lock, 105 const chrono::time_point<_Clock, _Duration>& __atime) 106 { 107 // DR 887 - Sync unknown clock to known clock. 108 const typename _Clock::time_point __c_entry = _Clock::now(); 109 const __clock_t::time_point __s_entry = __clock_t::now(); 110 const auto __delta = __atime - __c_entry; 111 const auto __s_atime = __s_entry + __delta; 112 113 return __wait_until_impl(__lock, __s_atime); 114 } 115 116 template<typename _Clock, typename _Duration, typename _Predicate> 117 bool 118 wait_until(unique_lock<mutex>& __lock, 119 const chrono::time_point<_Clock, _Duration>& __atime, 120 _Predicate __p) 121 { 122 while (!__p()) 123 if (wait_until(__lock, __atime) == cv_status::timeout) 124 return __p(); 125 return true; 126 } 127 128 template<typename _Rep, typename _Period> 129 cv_status 130 wait_for(unique_lock<mutex>& __lock, 131 const chrono::duration<_Rep, _Period>& __rtime) 132 { return wait_until(__lock, __clock_t::now() + __rtime); } 133 134 template<typename _Rep, typename _Period, typename _Predicate> 135 bool 136 wait_for(unique_lock<mutex>& __lock, 137 const chrono::duration<_Rep, _Period>& __rtime, 138 _Predicate __p) 139 { return wait_until(__lock, __clock_t::now() + __rtime, std::move(__p)); } 140 141 native_handle_type 142 native_handle() 143 { return &_M_cond; } 144 145 private: 146 template<typename _Dur> 147 cv_status 148 __wait_until_impl(unique_lock<mutex>& __lock, 149 const chrono::time_point<__clock_t, _Dur>& __atime) 150 { 151 auto __s = chrono::time_point_cast<chrono::seconds>(__atime); 152 auto __ns = chrono::duration_cast<chrono::nanoseconds>(__atime - __s); 153 154 __gthread_time_t __ts = 155 { 156 static_cast<std::time_t>(__s.time_since_epoch().count()), 157 static_cast<long>(__ns.count()) 158 }; 159 160 __gthread_cond_timedwait(&_M_cond, __lock.mutex()->native_handle(), 161 &__ts); 162 163 return (__clock_t::now() < __atime 164 ? cv_status::no_timeout : cv_status::timeout); 165 } 166 }; 167 168 /// condition_variable_any 169 // Like above, but mutex is not required to have try_lock. 170 class condition_variable_any 171 { 172 typedef chrono::system_clock __clock_t; 173 condition_variable _M_cond; 174 mutex _M_mutex; 175 176 // scoped unlock - unlocks in ctor, re-locks in dtor 177 template<typename _Lock> 178 struct _Unlock 179 { 180 explicit _Unlock(_Lock& __lk) : _M_lock(__lk) { __lk.unlock(); } 181 182 ~_Unlock() noexcept(false) 183 { 184 if (uncaught_exception()) 185 __try { _M_lock.lock(); } __catch(...) { } 186 else 187 _M_lock.lock(); 188 } 189 190 _Unlock(const _Unlock&) = delete; 191 _Unlock& operator=(const _Unlock&) = delete; 192 193 _Lock& _M_lock; 194 }; 195 196 public: 197 198 condition_variable_any() noexcept; 199 ~condition_variable_any() noexcept; 200 201 condition_variable_any(const condition_variable_any&) = delete; 202 condition_variable_any& operator=(const condition_variable_any&) = delete; 203 204 void 205 notify_one() noexcept 206 { 207 lock_guard<mutex> __lock(_M_mutex); 208 _M_cond.notify_one(); 209 } 210 211 void 212 notify_all() noexcept 213 { 214 lock_guard<mutex> __lock(_M_mutex); 215 _M_cond.notify_all(); 216 } 217 218 template<typename _Lock> 219 void 220 wait(_Lock& __lock) 221 { 222 unique_lock<mutex> __my_lock(_M_mutex); 223 _Unlock<_Lock> __unlock(__lock); 224 // _M_mutex must be unlocked before re-locking __lock so move 225 // ownership of _M_mutex lock to an object with shorter lifetime. 226 unique_lock<mutex> __my_lock2(std::move(__my_lock)); 227 _M_cond.wait(__my_lock2); 228 } 229 230 231 template<typename _Lock, typename _Predicate> 232 void 233 wait(_Lock& __lock, _Predicate __p) 234 { 235 while (!__p()) 236 wait(__lock); 237 } 238 239 template<typename _Lock, typename _Clock, typename _Duration> 240 cv_status 241 wait_until(_Lock& __lock, 242 const chrono::time_point<_Clock, _Duration>& __atime) 243 { 244 unique_lock<mutex> __my_lock(_M_mutex); 245 _Unlock<_Lock> __unlock(__lock); 246 // _M_mutex must be unlocked before re-locking __lock so move 247 // ownership of _M_mutex lock to an object with shorter lifetime. 248 unique_lock<mutex> __my_lock2(std::move(__my_lock)); 249 return _M_cond.wait_until(__my_lock2, __atime); 250 } 251 252 template<typename _Lock, typename _Clock, 253 typename _Duration, typename _Predicate> 254 bool 255 wait_until(_Lock& __lock, 256 const chrono::time_point<_Clock, _Duration>& __atime, 257 _Predicate __p) 258 { 259 while (!__p()) 260 if (wait_until(__lock, __atime) == cv_status::timeout) 261 return __p(); 262 return true; 263 } 264 265 template<typename _Lock, typename _Rep, typename _Period> 266 cv_status 267 wait_for(_Lock& __lock, const chrono::duration<_Rep, _Period>& __rtime) 268 { return wait_until(__lock, __clock_t::now() + __rtime); } 269 270 template<typename _Lock, typename _Rep, 271 typename _Period, typename _Predicate> 272 bool 273 wait_for(_Lock& __lock, 274 const chrono::duration<_Rep, _Period>& __rtime, _Predicate __p) 275 { return wait_until(__lock, __clock_t::now() + __rtime, std::move(__p)); } 276 }; 277 278 // @} group condition_variables 279 _GLIBCXX_END_NAMESPACE_VERSION 280 } // namespace 281 282 #endif // _GLIBCXX_HAS_GTHREADS && _GLIBCXX_USE_C99_STDINT_TR1 283 284 #endif // C++11 285 286 #endif // _GLIBCXX_CONDITION_VARIABLE 287
