libstdc++
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00001 // <condition_variable> -*- C++ -*- 00002 00003 // Copyright (C) 2008-2014 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 inline namespace _V2 { 00174 00175 /// condition_variable_any 00176 // Like above, but mutex is not required to have try_lock. 00177 class condition_variable_any 00178 { 00179 typedef chrono::system_clock __clock_t; 00180 condition_variable _M_cond; 00181 shared_ptr<mutex> _M_mutex; 00182 00183 // scoped unlock - unlocks in ctor, re-locks in dtor 00184 template<typename _Lock> 00185 struct _Unlock 00186 { 00187 explicit _Unlock(_Lock& __lk) : _M_lock(__lk) { __lk.unlock(); } 00188 00189 ~_Unlock() noexcept(false) 00190 { 00191 if (uncaught_exception()) 00192 { 00193 __try 00194 { _M_lock.lock(); } 00195 __catch(const __cxxabiv1::__forced_unwind&) 00196 { __throw_exception_again; } 00197 __catch(...) 00198 { } 00199 } 00200 else 00201 _M_lock.lock(); 00202 } 00203 00204 _Unlock(const _Unlock&) = delete; 00205 _Unlock& operator=(const _Unlock&) = delete; 00206 00207 _Lock& _M_lock; 00208 }; 00209 00210 public: 00211 condition_variable_any() : _M_mutex(std::make_shared<mutex>()) { } 00212 ~condition_variable_any() = default; 00213 00214 condition_variable_any(const condition_variable_any&) = delete; 00215 condition_variable_any& operator=(const condition_variable_any&) = delete; 00216 00217 void 00218 notify_one() noexcept 00219 { 00220 lock_guard<mutex> __lock(*_M_mutex); 00221 _M_cond.notify_one(); 00222 } 00223 00224 void 00225 notify_all() noexcept 00226 { 00227 lock_guard<mutex> __lock(*_M_mutex); 00228 _M_cond.notify_all(); 00229 } 00230 00231 template<typename _Lock> 00232 void 00233 wait(_Lock& __lock) 00234 { 00235 shared_ptr<mutex> __mutex = _M_mutex; 00236 unique_lock<mutex> __my_lock(*__mutex); 00237 _Unlock<_Lock> __unlock(__lock); 00238 // *__mutex must be unlocked before re-locking __lock so move 00239 // ownership of *__mutex lock to an object with shorter lifetime. 00240 unique_lock<mutex> __my_lock2(std::move(__my_lock)); 00241 _M_cond.wait(__my_lock2); 00242 } 00243 00244 00245 template<typename _Lock, typename _Predicate> 00246 void 00247 wait(_Lock& __lock, _Predicate __p) 00248 { 00249 while (!__p()) 00250 wait(__lock); 00251 } 00252 00253 template<typename _Lock, typename _Clock, typename _Duration> 00254 cv_status 00255 wait_until(_Lock& __lock, 00256 const chrono::time_point<_Clock, _Duration>& __atime) 00257 { 00258 shared_ptr<mutex> __mutex = _M_mutex; 00259 unique_lock<mutex> __my_lock(*__mutex); 00260 _Unlock<_Lock> __unlock(__lock); 00261 // *__mutex must be unlocked before re-locking __lock so move 00262 // ownership of *__mutex lock to an object with shorter lifetime. 00263 unique_lock<mutex> __my_lock2(std::move(__my_lock)); 00264 return _M_cond.wait_until(__my_lock2, __atime); 00265 } 00266 00267 template<typename _Lock, typename _Clock, 00268 typename _Duration, typename _Predicate> 00269 bool 00270 wait_until(_Lock& __lock, 00271 const chrono::time_point<_Clock, _Duration>& __atime, 00272 _Predicate __p) 00273 { 00274 while (!__p()) 00275 if (wait_until(__lock, __atime) == cv_status::timeout) 00276 return __p(); 00277 return true; 00278 } 00279 00280 template<typename _Lock, typename _Rep, typename _Period> 00281 cv_status 00282 wait_for(_Lock& __lock, const chrono::duration<_Rep, _Period>& __rtime) 00283 { return wait_until(__lock, __clock_t::now() + __rtime); } 00284 00285 template<typename _Lock, typename _Rep, 00286 typename _Period, typename _Predicate> 00287 bool 00288 wait_for(_Lock& __lock, 00289 const chrono::duration<_Rep, _Period>& __rtime, _Predicate __p) 00290 { return wait_until(__lock, __clock_t::now() + __rtime, std::move(__p)); } 00291 }; 00292 00293 } // end inline namespace 00294 00295 // @} group condition_variables 00296 _GLIBCXX_END_NAMESPACE_VERSION 00297 } // namespace 00298 00299 #endif // _GLIBCXX_HAS_GTHREADS && _GLIBCXX_USE_C99_STDINT_TR1 00300 00301 #endif // C++11 00302 00303 #endif // _GLIBCXX_CONDITION_VARIABLE