libstdc++
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00001 // <condition_variable> -*- C++ -*- 00002 00003 // Copyright (C) 2008-2019 Free Software Foundation, Inc. 00004 // 00005 // This file is part of the GNU ISO C++ Library. This library is free 00006 // software; you can redistribute it and/or modify it under the 00007 // terms of the GNU General Public License as published by the 00008 // Free Software Foundation; either version 3, or (at your option) 00009 // any later version. 00010 00011 // This library is distributed in the hope that it will be useful, 00012 // but WITHOUT ANY WARRANTY; without even the implied warranty of 00013 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 00014 // GNU General Public License for more details. 00015 00016 // Under Section 7 of GPL version 3, you are granted additional 00017 // permissions described in the GCC Runtime Library Exception, version 00018 // 3.1, as published by the Free Software Foundation. 00019 00020 // You should have received a copy of the GNU General Public License and 00021 // a copy of the GCC Runtime Library Exception along with this program; 00022 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 00023 // <http://www.gnu.org/licenses/>. 00024 00025 /** @file include/condition_variable 00026 * This is a Standard C++ Library header. 00027 */ 00028 00029 #ifndef _GLIBCXX_CONDITION_VARIABLE 00030 #define _GLIBCXX_CONDITION_VARIABLE 1 00031 00032 #pragma GCC system_header 00033 00034 #if __cplusplus < 201103L 00035 # include <bits/c++0x_warning.h> 00036 #else 00037 00038 #include <chrono> 00039 #include <bits/std_mutex.h> 00040 #include <bits/unique_lock.h> 00041 #include <ext/concurrence.h> 00042 #include <bits/alloc_traits.h> 00043 #include <bits/allocator.h> 00044 #include <bits/unique_ptr.h> 00045 #include <bits/shared_ptr.h> 00046 #include <bits/cxxabi_forced.h> 00047 00048 #if defined(_GLIBCXX_HAS_GTHREADS) 00049 00050 namespace std _GLIBCXX_VISIBILITY(default) 00051 { 00052 _GLIBCXX_BEGIN_NAMESPACE_VERSION 00053 00054 /** 00055 * @defgroup condition_variables Condition Variables 00056 * @ingroup concurrency 00057 * 00058 * Classes for condition_variable support. 00059 * @{ 00060 */ 00061 00062 /// cv_status 00063 enum class cv_status { no_timeout, timeout }; 00064 00065 /// condition_variable 00066 class condition_variable 00067 { 00068 typedef chrono::system_clock __clock_t; 00069 typedef chrono::steady_clock __steady_clock_t; 00070 typedef __gthread_cond_t __native_type; 00071 00072 #ifdef __GTHREAD_COND_INIT 00073 __native_type _M_cond = __GTHREAD_COND_INIT; 00074 #else 00075 __native_type _M_cond; 00076 #endif 00077 00078 public: 00079 typedef __native_type* native_handle_type; 00080 00081 condition_variable() noexcept; 00082 ~condition_variable() noexcept; 00083 00084 condition_variable(const condition_variable&) = delete; 00085 condition_variable& operator=(const condition_variable&) = delete; 00086 00087 void 00088 notify_one() noexcept; 00089 00090 void 00091 notify_all() noexcept; 00092 00093 void 00094 wait(unique_lock<mutex>& __lock) noexcept; 00095 00096 template<typename _Predicate> 00097 void 00098 wait(unique_lock<mutex>& __lock, _Predicate __p) 00099 { 00100 while (!__p()) 00101 wait(__lock); 00102 } 00103 00104 template<typename _Duration> 00105 cv_status 00106 wait_until(unique_lock<mutex>& __lock, 00107 const chrono::time_point<__clock_t, _Duration>& __atime) 00108 { return __wait_until_impl(__lock, __atime); } 00109 00110 template<typename _Clock, typename _Duration> 00111 cv_status 00112 wait_until(unique_lock<mutex>& __lock, 00113 const chrono::time_point<_Clock, _Duration>& __atime) 00114 { 00115 // DR 887 - Sync unknown clock to known clock. 00116 const typename _Clock::time_point __c_entry = _Clock::now(); 00117 const __clock_t::time_point __s_entry = __clock_t::now(); 00118 const auto __delta = __atime - __c_entry; 00119 const auto __s_atime = __s_entry + __delta; 00120 00121 if (__wait_until_impl(__lock, __s_atime) == cv_status::no_timeout) 00122 return cv_status::no_timeout; 00123 // We got a timeout when measured against __clock_t but 00124 // we need to check against the caller-supplied clock 00125 // to tell whether we should return a timeout. 00126 if (_Clock::now() < __atime) 00127 return cv_status::no_timeout; 00128 return cv_status::timeout; 00129 } 00130 00131 template<typename _Clock, typename _Duration, typename _Predicate> 00132 bool 00133 wait_until(unique_lock<mutex>& __lock, 00134 const chrono::time_point<_Clock, _Duration>& __atime, 00135 _Predicate __p) 00136 { 00137 while (!__p()) 00138 if (wait_until(__lock, __atime) == cv_status::timeout) 00139 return __p(); 00140 return true; 00141 } 00142 00143 template<typename _Rep, typename _Period> 00144 cv_status 00145 wait_for(unique_lock<mutex>& __lock, 00146 const chrono::duration<_Rep, _Period>& __rtime) 00147 { 00148 using __dur = typename __steady_clock_t::duration; 00149 auto __reltime = chrono::duration_cast<__dur>(__rtime); 00150 if (__reltime < __rtime) 00151 ++__reltime; 00152 return wait_until(__lock, __steady_clock_t::now() + __reltime); 00153 } 00154 00155 template<typename _Rep, typename _Period, typename _Predicate> 00156 bool 00157 wait_for(unique_lock<mutex>& __lock, 00158 const chrono::duration<_Rep, _Period>& __rtime, 00159 _Predicate __p) 00160 { 00161 using __dur = typename __steady_clock_t::duration; 00162 auto __reltime = chrono::duration_cast<__dur>(__rtime); 00163 if (__reltime < __rtime) 00164 ++__reltime; 00165 return wait_until(__lock, __steady_clock_t::now() + __reltime, 00166 std::move(__p)); 00167 } 00168 00169 native_handle_type 00170 native_handle() 00171 { return &_M_cond; } 00172 00173 private: 00174 template<typename _Dur> 00175 cv_status 00176 __wait_until_impl(unique_lock<mutex>& __lock, 00177 const chrono::time_point<__clock_t, _Dur>& __atime) 00178 { 00179 auto __s = chrono::time_point_cast<chrono::seconds>(__atime); 00180 auto __ns = chrono::duration_cast<chrono::nanoseconds>(__atime - __s); 00181 00182 __gthread_time_t __ts = 00183 { 00184 static_cast<std::time_t>(__s.time_since_epoch().count()), 00185 static_cast<long>(__ns.count()) 00186 }; 00187 00188 __gthread_cond_timedwait(&_M_cond, __lock.mutex()->native_handle(), 00189 &__ts); 00190 00191 return (__clock_t::now() < __atime 00192 ? cv_status::no_timeout : cv_status::timeout); 00193 } 00194 }; 00195 00196 void 00197 notify_all_at_thread_exit(condition_variable&, unique_lock<mutex>); 00198 00199 struct __at_thread_exit_elt 00200 { 00201 __at_thread_exit_elt* _M_next; 00202 void (*_M_cb)(void*); 00203 }; 00204 00205 inline namespace _V2 { 00206 00207 /// condition_variable_any 00208 // Like above, but mutex is not required to have try_lock. 00209 class condition_variable_any 00210 { 00211 typedef chrono::system_clock __clock_t; 00212 condition_variable _M_cond; 00213 shared_ptr<mutex> _M_mutex; 00214 00215 // scoped unlock - unlocks in ctor, re-locks in dtor 00216 template<typename _Lock> 00217 struct _Unlock 00218 { 00219 explicit _Unlock(_Lock& __lk) : _M_lock(__lk) { __lk.unlock(); } 00220 00221 ~_Unlock() noexcept(false) 00222 { 00223 if (uncaught_exception()) 00224 { 00225 __try 00226 { _M_lock.lock(); } 00227 __catch(const __cxxabiv1::__forced_unwind&) 00228 { __throw_exception_again; } 00229 __catch(...) 00230 { } 00231 } 00232 else 00233 _M_lock.lock(); 00234 } 00235 00236 _Unlock(const _Unlock&) = delete; 00237 _Unlock& operator=(const _Unlock&) = delete; 00238 00239 _Lock& _M_lock; 00240 }; 00241 00242 public: 00243 condition_variable_any() : _M_mutex(std::make_shared<mutex>()) { } 00244 ~condition_variable_any() = default; 00245 00246 condition_variable_any(const condition_variable_any&) = delete; 00247 condition_variable_any& operator=(const condition_variable_any&) = delete; 00248 00249 void 00250 notify_one() noexcept 00251 { 00252 lock_guard<mutex> __lock(*_M_mutex); 00253 _M_cond.notify_one(); 00254 } 00255 00256 void 00257 notify_all() noexcept 00258 { 00259 lock_guard<mutex> __lock(*_M_mutex); 00260 _M_cond.notify_all(); 00261 } 00262 00263 template<typename _Lock> 00264 void 00265 wait(_Lock& __lock) 00266 { 00267 shared_ptr<mutex> __mutex = _M_mutex; 00268 unique_lock<mutex> __my_lock(*__mutex); 00269 _Unlock<_Lock> __unlock(__lock); 00270 // *__mutex must be unlocked before re-locking __lock so move 00271 // ownership of *__mutex lock to an object with shorter lifetime. 00272 unique_lock<mutex> __my_lock2(std::move(__my_lock)); 00273 _M_cond.wait(__my_lock2); 00274 } 00275 00276 00277 template<typename _Lock, typename _Predicate> 00278 void 00279 wait(_Lock& __lock, _Predicate __p) 00280 { 00281 while (!__p()) 00282 wait(__lock); 00283 } 00284 00285 template<typename _Lock, typename _Clock, typename _Duration> 00286 cv_status 00287 wait_until(_Lock& __lock, 00288 const chrono::time_point<_Clock, _Duration>& __atime) 00289 { 00290 shared_ptr<mutex> __mutex = _M_mutex; 00291 unique_lock<mutex> __my_lock(*__mutex); 00292 _Unlock<_Lock> __unlock(__lock); 00293 // *__mutex must be unlocked before re-locking __lock so move 00294 // ownership of *__mutex lock to an object with shorter lifetime. 00295 unique_lock<mutex> __my_lock2(std::move(__my_lock)); 00296 return _M_cond.wait_until(__my_lock2, __atime); 00297 } 00298 00299 template<typename _Lock, typename _Clock, 00300 typename _Duration, typename _Predicate> 00301 bool 00302 wait_until(_Lock& __lock, 00303 const chrono::time_point<_Clock, _Duration>& __atime, 00304 _Predicate __p) 00305 { 00306 while (!__p()) 00307 if (wait_until(__lock, __atime) == cv_status::timeout) 00308 return __p(); 00309 return true; 00310 } 00311 00312 template<typename _Lock, typename _Rep, typename _Period> 00313 cv_status 00314 wait_for(_Lock& __lock, const chrono::duration<_Rep, _Period>& __rtime) 00315 { return wait_until(__lock, __clock_t::now() + __rtime); } 00316 00317 template<typename _Lock, typename _Rep, 00318 typename _Period, typename _Predicate> 00319 bool 00320 wait_for(_Lock& __lock, 00321 const chrono::duration<_Rep, _Period>& __rtime, _Predicate __p) 00322 { return wait_until(__lock, __clock_t::now() + __rtime, std::move(__p)); } 00323 }; 00324 00325 } // end inline namespace 00326 00327 // @} group condition_variables 00328 _GLIBCXX_END_NAMESPACE_VERSION 00329 } // namespace 00330 00331 #endif // _GLIBCXX_HAS_GTHREADS 00332 #endif // C++11 00333 #endif // _GLIBCXX_CONDITION_VARIABLE