libstdc++
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00001 // <condition_variable> -*- C++ -*- 00002 00003 // Copyright (C) 2008-2015 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 <mutex> 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 00046 #if defined(_GLIBCXX_HAS_GTHREADS) && defined(_GLIBCXX_USE_C99_STDINT_TR1) 00047 00048 namespace std _GLIBCXX_VISIBILITY(default) 00049 { 00050 _GLIBCXX_BEGIN_NAMESPACE_VERSION 00051 00052 /** 00053 * @defgroup condition_variables Condition Variables 00054 * @ingroup concurrency 00055 * 00056 * Classes for condition_variable support. 00057 * @{ 00058 */ 00059 00060 /// cv_status 00061 enum class cv_status { no_timeout, timeout }; 00062 00063 /// condition_variable 00064 class condition_variable 00065 { 00066 typedef chrono::system_clock __clock_t; 00067 typedef __gthread_cond_t __native_type; 00068 00069 #ifdef __GTHREAD_COND_INIT 00070 __native_type _M_cond = __GTHREAD_COND_INIT; 00071 #else 00072 __native_type _M_cond; 00073 #endif 00074 00075 public: 00076 typedef __native_type* native_handle_type; 00077 00078 condition_variable() noexcept; 00079 ~condition_variable() noexcept; 00080 00081 condition_variable(const condition_variable&) = delete; 00082 condition_variable& operator=(const condition_variable&) = delete; 00083 00084 void 00085 notify_one() noexcept; 00086 00087 void 00088 notify_all() noexcept; 00089 00090 void 00091 wait(unique_lock<mutex>& __lock); 00092 00093 template<typename _Predicate> 00094 void 00095 wait(unique_lock<mutex>& __lock, _Predicate __p) 00096 { 00097 while (!__p()) 00098 wait(__lock); 00099 } 00100 00101 template<typename _Duration> 00102 cv_status 00103 wait_until(unique_lock<mutex>& __lock, 00104 const chrono::time_point<__clock_t, _Duration>& __atime) 00105 { return __wait_until_impl(__lock, __atime); } 00106 00107 template<typename _Clock, typename _Duration> 00108 cv_status 00109 wait_until(unique_lock<mutex>& __lock, 00110 const chrono::time_point<_Clock, _Duration>& __atime) 00111 { 00112 // DR 887 - Sync unknown clock to known clock. 00113 const typename _Clock::time_point __c_entry = _Clock::now(); 00114 const __clock_t::time_point __s_entry = __clock_t::now(); 00115 const auto __delta = __atime - __c_entry; 00116 const auto __s_atime = __s_entry + __delta; 00117 00118 return __wait_until_impl(__lock, __s_atime); 00119 } 00120 00121 template<typename _Clock, typename _Duration, typename _Predicate> 00122 bool 00123 wait_until(unique_lock<mutex>& __lock, 00124 const chrono::time_point<_Clock, _Duration>& __atime, 00125 _Predicate __p) 00126 { 00127 while (!__p()) 00128 if (wait_until(__lock, __atime) == cv_status::timeout) 00129 return __p(); 00130 return true; 00131 } 00132 00133 template<typename _Rep, typename _Period> 00134 cv_status 00135 wait_for(unique_lock<mutex>& __lock, 00136 const chrono::duration<_Rep, _Period>& __rtime) 00137 { return wait_until(__lock, __clock_t::now() + __rtime); } 00138 00139 template<typename _Rep, typename _Period, typename _Predicate> 00140 bool 00141 wait_for(unique_lock<mutex>& __lock, 00142 const chrono::duration<_Rep, _Period>& __rtime, 00143 _Predicate __p) 00144 { return wait_until(__lock, __clock_t::now() + __rtime, std::move(__p)); } 00145 00146 native_handle_type 00147 native_handle() 00148 { return &_M_cond; } 00149 00150 private: 00151 template<typename _Dur> 00152 cv_status 00153 __wait_until_impl(unique_lock<mutex>& __lock, 00154 const chrono::time_point<__clock_t, _Dur>& __atime) 00155 { 00156 auto __s = chrono::time_point_cast<chrono::seconds>(__atime); 00157 auto __ns = chrono::duration_cast<chrono::nanoseconds>(__atime - __s); 00158 00159 __gthread_time_t __ts = 00160 { 00161 static_cast<std::time_t>(__s.time_since_epoch().count()), 00162 static_cast<long>(__ns.count()) 00163 }; 00164 00165 __gthread_cond_timedwait(&_M_cond, __lock.mutex()->native_handle(), 00166 &__ts); 00167 00168 return (__clock_t::now() < __atime 00169 ? cv_status::no_timeout : cv_status::timeout); 00170 } 00171 }; 00172 00173 void 00174 notify_all_at_thread_exit(condition_variable&, unique_lock<mutex>); 00175 00176 struct __at_thread_exit_elt 00177 { 00178 __at_thread_exit_elt* _M_next; 00179 void (*_M_cb)(void*); 00180 }; 00181 00182 inline namespace _V2 { 00183 00184 /// condition_variable_any 00185 // Like above, but mutex is not required to have try_lock. 00186 class condition_variable_any 00187 { 00188 typedef chrono::system_clock __clock_t; 00189 condition_variable _M_cond; 00190 shared_ptr<mutex> _M_mutex; 00191 00192 // scoped unlock - unlocks in ctor, re-locks in dtor 00193 template<typename _Lock> 00194 struct _Unlock 00195 { 00196 explicit _Unlock(_Lock& __lk) : _M_lock(__lk) { __lk.unlock(); } 00197 00198 ~_Unlock() noexcept(false) 00199 { 00200 if (uncaught_exception()) 00201 { 00202 __try 00203 { _M_lock.lock(); } 00204 __catch(const __cxxabiv1::__forced_unwind&) 00205 { __throw_exception_again; } 00206 __catch(...) 00207 { } 00208 } 00209 else 00210 _M_lock.lock(); 00211 } 00212 00213 _Unlock(const _Unlock&) = delete; 00214 _Unlock& operator=(const _Unlock&) = delete; 00215 00216 _Lock& _M_lock; 00217 }; 00218 00219 public: 00220 condition_variable_any() : _M_mutex(std::make_shared<mutex>()) { } 00221 ~condition_variable_any() = default; 00222 00223 condition_variable_any(const condition_variable_any&) = delete; 00224 condition_variable_any& operator=(const condition_variable_any&) = delete; 00225 00226 void 00227 notify_one() noexcept 00228 { 00229 lock_guard<mutex> __lock(*_M_mutex); 00230 _M_cond.notify_one(); 00231 } 00232 00233 void 00234 notify_all() noexcept 00235 { 00236 lock_guard<mutex> __lock(*_M_mutex); 00237 _M_cond.notify_all(); 00238 } 00239 00240 template<typename _Lock> 00241 void 00242 wait(_Lock& __lock) 00243 { 00244 shared_ptr<mutex> __mutex = _M_mutex; 00245 unique_lock<mutex> __my_lock(*__mutex); 00246 _Unlock<_Lock> __unlock(__lock); 00247 // *__mutex must be unlocked before re-locking __lock so move 00248 // ownership of *__mutex lock to an object with shorter lifetime. 00249 unique_lock<mutex> __my_lock2(std::move(__my_lock)); 00250 _M_cond.wait(__my_lock2); 00251 } 00252 00253 00254 template<typename _Lock, typename _Predicate> 00255 void 00256 wait(_Lock& __lock, _Predicate __p) 00257 { 00258 while (!__p()) 00259 wait(__lock); 00260 } 00261 00262 template<typename _Lock, typename _Clock, typename _Duration> 00263 cv_status 00264 wait_until(_Lock& __lock, 00265 const chrono::time_point<_Clock, _Duration>& __atime) 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 return _M_cond.wait_until(__my_lock2, __atime); 00274 } 00275 00276 template<typename _Lock, typename _Clock, 00277 typename _Duration, typename _Predicate> 00278 bool 00279 wait_until(_Lock& __lock, 00280 const chrono::time_point<_Clock, _Duration>& __atime, 00281 _Predicate __p) 00282 { 00283 while (!__p()) 00284 if (wait_until(__lock, __atime) == cv_status::timeout) 00285 return __p(); 00286 return true; 00287 } 00288 00289 template<typename _Lock, typename _Rep, typename _Period> 00290 cv_status 00291 wait_for(_Lock& __lock, const chrono::duration<_Rep, _Period>& __rtime) 00292 { return wait_until(__lock, __clock_t::now() + __rtime); } 00293 00294 template<typename _Lock, typename _Rep, 00295 typename _Period, typename _Predicate> 00296 bool 00297 wait_for(_Lock& __lock, 00298 const chrono::duration<_Rep, _Period>& __rtime, _Predicate __p) 00299 { return wait_until(__lock, __clock_t::now() + __rtime, std::move(__p)); } 00300 }; 00301 00302 } // end inline namespace 00303 00304 // @} group condition_variables 00305 _GLIBCXX_END_NAMESPACE_VERSION 00306 } // namespace 00307 00308 #endif // _GLIBCXX_HAS_GTHREADS && _GLIBCXX_USE_C99_STDINT_TR1 00309 00310 #endif // C++11 00311 00312 #endif // _GLIBCXX_CONDITION_VARIABLE