libstdc++
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00001 // <condition_variable> -*- C++ -*- 00002 00003 // Copyright (C) 2008-2018 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 <ext/concurrence.h> 00041 #include <bits/alloc_traits.h> 00042 #include <bits/allocator.h> 00043 #include <bits/unique_ptr.h> 00044 #include <bits/shared_ptr.h> 00045 #include <bits/cxxabi_forced.h> 00046 00047 #if defined(_GLIBCXX_HAS_GTHREADS) && defined(_GLIBCXX_USE_C99_STDINT_TR1) 00048 00049 namespace std _GLIBCXX_VISIBILITY(default) 00050 { 00051 _GLIBCXX_BEGIN_NAMESPACE_VERSION 00052 00053 /** 00054 * @defgroup condition_variables Condition Variables 00055 * @ingroup concurrency 00056 * 00057 * Classes for condition_variable support. 00058 * @{ 00059 */ 00060 00061 /// cv_status 00062 enum class cv_status { no_timeout, timeout }; 00063 00064 /// condition_variable 00065 class condition_variable 00066 { 00067 typedef chrono::system_clock __clock_t; 00068 typedef __gthread_cond_t __native_type; 00069 00070 #ifdef __GTHREAD_COND_INIT 00071 __native_type _M_cond = __GTHREAD_COND_INIT; 00072 #else 00073 __native_type _M_cond; 00074 #endif 00075 00076 public: 00077 typedef __native_type* native_handle_type; 00078 00079 condition_variable() noexcept; 00080 ~condition_variable() noexcept; 00081 00082 condition_variable(const condition_variable&) = delete; 00083 condition_variable& operator=(const condition_variable&) = delete; 00084 00085 void 00086 notify_one() noexcept; 00087 00088 void 00089 notify_all() noexcept; 00090 00091 void 00092 wait(unique_lock<mutex>& __lock) noexcept; 00093 00094 template<typename _Predicate> 00095 void 00096 wait(unique_lock<mutex>& __lock, _Predicate __p) 00097 { 00098 while (!__p()) 00099 wait(__lock); 00100 } 00101 00102 template<typename _Duration> 00103 cv_status 00104 wait_until(unique_lock<mutex>& __lock, 00105 const chrono::time_point<__clock_t, _Duration>& __atime) 00106 { return __wait_until_impl(__lock, __atime); } 00107 00108 template<typename _Clock, typename _Duration> 00109 cv_status 00110 wait_until(unique_lock<mutex>& __lock, 00111 const chrono::time_point<_Clock, _Duration>& __atime) 00112 { 00113 // DR 887 - Sync unknown clock to known clock. 00114 const typename _Clock::time_point __c_entry = _Clock::now(); 00115 const __clock_t::time_point __s_entry = __clock_t::now(); 00116 const auto __delta = __atime - __c_entry; 00117 const auto __s_atime = __s_entry + __delta; 00118 00119 return __wait_until_impl(__lock, __s_atime); 00120 } 00121 00122 template<typename _Clock, typename _Duration, typename _Predicate> 00123 bool 00124 wait_until(unique_lock<mutex>& __lock, 00125 const chrono::time_point<_Clock, _Duration>& __atime, 00126 _Predicate __p) 00127 { 00128 while (!__p()) 00129 if (wait_until(__lock, __atime) == cv_status::timeout) 00130 return __p(); 00131 return true; 00132 } 00133 00134 template<typename _Rep, typename _Period> 00135 cv_status 00136 wait_for(unique_lock<mutex>& __lock, 00137 const chrono::duration<_Rep, _Period>& __rtime) 00138 { 00139 using __dur = typename __clock_t::duration; 00140 auto __reltime = chrono::duration_cast<__dur>(__rtime); 00141 if (__reltime < __rtime) 00142 ++__reltime; 00143 return wait_until(__lock, __clock_t::now() + __reltime); 00144 } 00145 00146 template<typename _Rep, typename _Period, typename _Predicate> 00147 bool 00148 wait_for(unique_lock<mutex>& __lock, 00149 const chrono::duration<_Rep, _Period>& __rtime, 00150 _Predicate __p) 00151 { 00152 using __dur = typename __clock_t::duration; 00153 auto __reltime = chrono::duration_cast<__dur>(__rtime); 00154 if (__reltime < __rtime) 00155 ++__reltime; 00156 return wait_until(__lock, __clock_t::now() + __reltime, std::move(__p)); 00157 } 00158 00159 native_handle_type 00160 native_handle() 00161 { return &_M_cond; } 00162 00163 private: 00164 template<typename _Dur> 00165 cv_status 00166 __wait_until_impl(unique_lock<mutex>& __lock, 00167 const chrono::time_point<__clock_t, _Dur>& __atime) 00168 { 00169 auto __s = chrono::time_point_cast<chrono::seconds>(__atime); 00170 auto __ns = chrono::duration_cast<chrono::nanoseconds>(__atime - __s); 00171 00172 __gthread_time_t __ts = 00173 { 00174 static_cast<std::time_t>(__s.time_since_epoch().count()), 00175 static_cast<long>(__ns.count()) 00176 }; 00177 00178 __gthread_cond_timedwait(&_M_cond, __lock.mutex()->native_handle(), 00179 &__ts); 00180 00181 return (__clock_t::now() < __atime 00182 ? cv_status::no_timeout : cv_status::timeout); 00183 } 00184 }; 00185 00186 void 00187 notify_all_at_thread_exit(condition_variable&, unique_lock<mutex>); 00188 00189 struct __at_thread_exit_elt 00190 { 00191 __at_thread_exit_elt* _M_next; 00192 void (*_M_cb)(void*); 00193 }; 00194 00195 inline namespace _V2 { 00196 00197 /// condition_variable_any 00198 // Like above, but mutex is not required to have try_lock. 00199 class condition_variable_any 00200 { 00201 typedef chrono::system_clock __clock_t; 00202 condition_variable _M_cond; 00203 shared_ptr<mutex> _M_mutex; 00204 00205 // scoped unlock - unlocks in ctor, re-locks in dtor 00206 template<typename _Lock> 00207 struct _Unlock 00208 { 00209 explicit _Unlock(_Lock& __lk) : _M_lock(__lk) { __lk.unlock(); } 00210 00211 ~_Unlock() noexcept(false) 00212 { 00213 if (uncaught_exception()) 00214 { 00215 __try 00216 { _M_lock.lock(); } 00217 __catch(const __cxxabiv1::__forced_unwind&) 00218 { __throw_exception_again; } 00219 __catch(...) 00220 { } 00221 } 00222 else 00223 _M_lock.lock(); 00224 } 00225 00226 _Unlock(const _Unlock&) = delete; 00227 _Unlock& operator=(const _Unlock&) = delete; 00228 00229 _Lock& _M_lock; 00230 }; 00231 00232 public: 00233 condition_variable_any() : _M_mutex(std::make_shared<mutex>()) { } 00234 ~condition_variable_any() = default; 00235 00236 condition_variable_any(const condition_variable_any&) = delete; 00237 condition_variable_any& operator=(const condition_variable_any&) = delete; 00238 00239 void 00240 notify_one() noexcept 00241 { 00242 lock_guard<mutex> __lock(*_M_mutex); 00243 _M_cond.notify_one(); 00244 } 00245 00246 void 00247 notify_all() noexcept 00248 { 00249 lock_guard<mutex> __lock(*_M_mutex); 00250 _M_cond.notify_all(); 00251 } 00252 00253 template<typename _Lock> 00254 void 00255 wait(_Lock& __lock) 00256 { 00257 shared_ptr<mutex> __mutex = _M_mutex; 00258 unique_lock<mutex> __my_lock(*__mutex); 00259 _Unlock<_Lock> __unlock(__lock); 00260 // *__mutex must be unlocked before re-locking __lock so move 00261 // ownership of *__mutex lock to an object with shorter lifetime. 00262 unique_lock<mutex> __my_lock2(std::move(__my_lock)); 00263 _M_cond.wait(__my_lock2); 00264 } 00265 00266 00267 template<typename _Lock, typename _Predicate> 00268 void 00269 wait(_Lock& __lock, _Predicate __p) 00270 { 00271 while (!__p()) 00272 wait(__lock); 00273 } 00274 00275 template<typename _Lock, typename _Clock, typename _Duration> 00276 cv_status 00277 wait_until(_Lock& __lock, 00278 const chrono::time_point<_Clock, _Duration>& __atime) 00279 { 00280 shared_ptr<mutex> __mutex = _M_mutex; 00281 unique_lock<mutex> __my_lock(*__mutex); 00282 _Unlock<_Lock> __unlock(__lock); 00283 // *__mutex must be unlocked before re-locking __lock so move 00284 // ownership of *__mutex lock to an object with shorter lifetime. 00285 unique_lock<mutex> __my_lock2(std::move(__my_lock)); 00286 return _M_cond.wait_until(__my_lock2, __atime); 00287 } 00288 00289 template<typename _Lock, typename _Clock, 00290 typename _Duration, typename _Predicate> 00291 bool 00292 wait_until(_Lock& __lock, 00293 const chrono::time_point<_Clock, _Duration>& __atime, 00294 _Predicate __p) 00295 { 00296 while (!__p()) 00297 if (wait_until(__lock, __atime) == cv_status::timeout) 00298 return __p(); 00299 return true; 00300 } 00301 00302 template<typename _Lock, typename _Rep, typename _Period> 00303 cv_status 00304 wait_for(_Lock& __lock, const chrono::duration<_Rep, _Period>& __rtime) 00305 { return wait_until(__lock, __clock_t::now() + __rtime); } 00306 00307 template<typename _Lock, typename _Rep, 00308 typename _Period, typename _Predicate> 00309 bool 00310 wait_for(_Lock& __lock, 00311 const chrono::duration<_Rep, _Period>& __rtime, _Predicate __p) 00312 { return wait_until(__lock, __clock_t::now() + __rtime, std::move(__p)); } 00313 }; 00314 00315 } // end inline namespace 00316 00317 // @} group condition_variables 00318 _GLIBCXX_END_NAMESPACE_VERSION 00319 } // namespace 00320 00321 #endif // _GLIBCXX_HAS_GTHREADS && _GLIBCXX_USE_C99_STDINT_TR1 00322 00323 #endif // C++11 00324 00325 #endif // _GLIBCXX_CONDITION_VARIABLE