libstdc++
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00001 // <condition_variable> -*- C++ -*- 00002 00003 // Copyright (C) 2008-2013 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> // unique_lock 00040 00041 #if defined(_GLIBCXX_HAS_GTHREADS) && defined(_GLIBCXX_USE_C99_STDINT_TR1) 00042 00043 namespace std _GLIBCXX_VISIBILITY(default) 00044 { 00045 _GLIBCXX_BEGIN_NAMESPACE_VERSION 00046 00047 /** 00048 * @defgroup condition_variables Condition Variables 00049 * @ingroup concurrency 00050 * 00051 * Classes for condition_variable support. 00052 * @{ 00053 */ 00054 00055 /// cv_status 00056 enum class cv_status { no_timeout, timeout }; 00057 00058 /// condition_variable 00059 class condition_variable 00060 { 00061 typedef chrono::system_clock __clock_t; 00062 typedef __gthread_cond_t __native_type; 00063 00064 #ifdef __GTHREAD_COND_INIT 00065 __native_type _M_cond = __GTHREAD_COND_INIT; 00066 #else 00067 __native_type _M_cond; 00068 #endif 00069 00070 public: 00071 typedef __native_type* native_handle_type; 00072 00073 condition_variable() noexcept; 00074 ~condition_variable() noexcept; 00075 00076 condition_variable(const condition_variable&) = delete; 00077 condition_variable& operator=(const condition_variable&) = delete; 00078 00079 void 00080 notify_one() noexcept; 00081 00082 void 00083 notify_all() noexcept; 00084 00085 void 00086 wait(unique_lock<mutex>& __lock); 00087 00088 template<typename _Predicate> 00089 void 00090 wait(unique_lock<mutex>& __lock, _Predicate __p) 00091 { 00092 while (!__p()) 00093 wait(__lock); 00094 } 00095 00096 template<typename _Duration> 00097 cv_status 00098 wait_until(unique_lock<mutex>& __lock, 00099 const chrono::time_point<__clock_t, _Duration>& __atime) 00100 { return __wait_until_impl(__lock, __atime); } 00101 00102 template<typename _Clock, typename _Duration> 00103 cv_status 00104 wait_until(unique_lock<mutex>& __lock, 00105 const chrono::time_point<_Clock, _Duration>& __atime) 00106 { 00107 // DR 887 - Sync unknown clock to known clock. 00108 const typename _Clock::time_point __c_entry = _Clock::now(); 00109 const __clock_t::time_point __s_entry = __clock_t::now(); 00110 const auto __delta = __atime - __c_entry; 00111 const auto __s_atime = __s_entry + __delta; 00112 00113 return __wait_until_impl(__lock, __s_atime); 00114 } 00115 00116 template<typename _Clock, typename _Duration, typename _Predicate> 00117 bool 00118 wait_until(unique_lock<mutex>& __lock, 00119 const chrono::time_point<_Clock, _Duration>& __atime, 00120 _Predicate __p) 00121 { 00122 while (!__p()) 00123 if (wait_until(__lock, __atime) == cv_status::timeout) 00124 return __p(); 00125 return true; 00126 } 00127 00128 template<typename _Rep, typename _Period> 00129 cv_status 00130 wait_for(unique_lock<mutex>& __lock, 00131 const chrono::duration<_Rep, _Period>& __rtime) 00132 { return wait_until(__lock, __clock_t::now() + __rtime); } 00133 00134 template<typename _Rep, typename _Period, typename _Predicate> 00135 bool 00136 wait_for(unique_lock<mutex>& __lock, 00137 const chrono::duration<_Rep, _Period>& __rtime, 00138 _Predicate __p) 00139 { return wait_until(__lock, __clock_t::now() + __rtime, std::move(__p)); } 00140 00141 native_handle_type 00142 native_handle() 00143 { return &_M_cond; } 00144 00145 private: 00146 template<typename _Dur> 00147 cv_status 00148 __wait_until_impl(unique_lock<mutex>& __lock, 00149 const chrono::time_point<__clock_t, _Dur>& __atime) 00150 { 00151 auto __s = chrono::time_point_cast<chrono::seconds>(__atime); 00152 auto __ns = chrono::duration_cast<chrono::nanoseconds>(__atime - __s); 00153 00154 __gthread_time_t __ts = 00155 { 00156 static_cast<std::time_t>(__s.time_since_epoch().count()), 00157 static_cast<long>(__ns.count()) 00158 }; 00159 00160 __gthread_cond_timedwait(&_M_cond, __lock.mutex()->native_handle(), 00161 &__ts); 00162 00163 return (__clock_t::now() < __atime 00164 ? cv_status::no_timeout : cv_status::timeout); 00165 } 00166 }; 00167 00168 /// condition_variable_any 00169 // Like above, but mutex is not required to have try_lock. 00170 class condition_variable_any 00171 { 00172 typedef chrono::system_clock __clock_t; 00173 condition_variable _M_cond; 00174 mutex _M_mutex; 00175 00176 // scoped unlock - unlocks in ctor, re-locks in dtor 00177 template<typename _Lock> 00178 struct _Unlock 00179 { 00180 explicit _Unlock(_Lock& __lk) : _M_lock(__lk) { __lk.unlock(); } 00181 00182 ~_Unlock() noexcept(false) 00183 { 00184 if (uncaught_exception()) 00185 __try { _M_lock.lock(); } __catch(...) { } 00186 else 00187 _M_lock.lock(); 00188 } 00189 00190 _Unlock(const _Unlock&) = delete; 00191 _Unlock& operator=(const _Unlock&) = delete; 00192 00193 _Lock& _M_lock; 00194 }; 00195 00196 public: 00197 00198 condition_variable_any() noexcept; 00199 ~condition_variable_any() noexcept; 00200 00201 condition_variable_any(const condition_variable_any&) = delete; 00202 condition_variable_any& operator=(const condition_variable_any&) = delete; 00203 00204 void 00205 notify_one() noexcept 00206 { 00207 lock_guard<mutex> __lock(_M_mutex); 00208 _M_cond.notify_one(); 00209 } 00210 00211 void 00212 notify_all() noexcept 00213 { 00214 lock_guard<mutex> __lock(_M_mutex); 00215 _M_cond.notify_all(); 00216 } 00217 00218 template<typename _Lock> 00219 void 00220 wait(_Lock& __lock) 00221 { 00222 unique_lock<mutex> __my_lock(_M_mutex); 00223 _Unlock<_Lock> __unlock(__lock); 00224 // _M_mutex must be unlocked before re-locking __lock so move 00225 // ownership of _M_mutex lock to an object with shorter lifetime. 00226 unique_lock<mutex> __my_lock2(std::move(__my_lock)); 00227 _M_cond.wait(__my_lock2); 00228 } 00229 00230 00231 template<typename _Lock, typename _Predicate> 00232 void 00233 wait(_Lock& __lock, _Predicate __p) 00234 { 00235 while (!__p()) 00236 wait(__lock); 00237 } 00238 00239 template<typename _Lock, typename _Clock, typename _Duration> 00240 cv_status 00241 wait_until(_Lock& __lock, 00242 const chrono::time_point<_Clock, _Duration>& __atime) 00243 { 00244 unique_lock<mutex> __my_lock(_M_mutex); 00245 _Unlock<_Lock> __unlock(__lock); 00246 // _M_mutex must be unlocked before re-locking __lock so move 00247 // ownership of _M_mutex lock to an object with shorter lifetime. 00248 unique_lock<mutex> __my_lock2(std::move(__my_lock)); 00249 return _M_cond.wait_until(__my_lock2, __atime); 00250 } 00251 00252 template<typename _Lock, typename _Clock, 00253 typename _Duration, typename _Predicate> 00254 bool 00255 wait_until(_Lock& __lock, 00256 const chrono::time_point<_Clock, _Duration>& __atime, 00257 _Predicate __p) 00258 { 00259 while (!__p()) 00260 if (wait_until(__lock, __atime) == cv_status::timeout) 00261 return __p(); 00262 return true; 00263 } 00264 00265 template<typename _Lock, typename _Rep, typename _Period> 00266 cv_status 00267 wait_for(_Lock& __lock, const chrono::duration<_Rep, _Period>& __rtime) 00268 { return wait_until(__lock, __clock_t::now() + __rtime); } 00269 00270 template<typename _Lock, typename _Rep, 00271 typename _Period, typename _Predicate> 00272 bool 00273 wait_for(_Lock& __lock, 00274 const chrono::duration<_Rep, _Period>& __rtime, _Predicate __p) 00275 { return wait_until(__lock, __clock_t::now() + __rtime, std::move(__p)); } 00276 }; 00277 00278 // @} group condition_variables 00279 _GLIBCXX_END_NAMESPACE_VERSION 00280 } // namespace 00281 00282 #endif // _GLIBCXX_HAS_GTHREADS && _GLIBCXX_USE_C99_STDINT_TR1 00283 00284 #endif // C++11 00285 00286 #endif // _GLIBCXX_CONDITION_VARIABLE