condition_variable

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00001 // <condition_variable> -*- C++ -*-
00002 
00003 // Copyright (C) 2008, 2009 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 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 #ifndef __GXX_EXPERIMENTAL_CXX0X__
00035 # include <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
00044 {
00045   /**
00046    * @defgroup condition_variables Condition Variables
00047    * @ingroup concurrency
00048    *
00049    * Classes for condition_variable support.
00050    * @{
00051    */
00052 
00053   /// condition_variable
00054   class condition_variable
00055   {
00056     typedef chrono::system_clock    __clock_t;
00057     typedef __gthread_cond_t        __native_type;
00058     __native_type           _M_cond;
00059 
00060   public:
00061     typedef __native_type*      native_handle_type;
00062 
00063     condition_variable();
00064     ~condition_variable();
00065 
00066     condition_variable(const condition_variable&) = delete;
00067     condition_variable& operator=(const condition_variable&) = delete;
00068 
00069     void
00070     notify_one();
00071 
00072     void
00073     notify_all();
00074 
00075     void
00076     wait(unique_lock<mutex>& __lock);
00077 
00078     template<typename _Predicate>
00079       void
00080       wait(unique_lock<mutex>& __lock, _Predicate __p)
00081       {
00082     while (!__p())
00083       wait(__lock);
00084       }
00085 
00086     template<typename _Duration>
00087       bool
00088       wait_until(unique_lock<mutex>& __lock,
00089          const chrono::time_point<__clock_t, _Duration>& __atime)
00090       { return __wait_until_impl(__lock, __atime); }
00091 
00092     template<typename _Clock, typename _Duration>
00093       bool
00094       wait_until(unique_lock<mutex>& __lock,
00095          const chrono::time_point<_Clock, _Duration>& __atime)
00096       {
00097     // DR 887 - Sync unknown clock to known clock.
00098     typename _Clock::time_point __c_entry = _Clock::now();
00099     __clock_t::time_point __s_entry = __clock_t::now();
00100     chrono::nanoseconds __delta = __atime - __c_entry;
00101     __clock_t::time_point __s_atime = __s_entry + __delta;
00102 
00103     return __wait_until_impl(__lock, __s_atime);
00104       }
00105 
00106     template<typename _Clock, typename _Duration, typename _Predicate>
00107       bool
00108       wait_until(unique_lock<mutex>& __lock,
00109          const chrono::time_point<_Clock, _Duration>& __atime,
00110          _Predicate __p)
00111       {
00112     while (!__p())
00113       if (!wait_until(__lock, __atime))
00114         return __p();
00115 
00116     return true;
00117       }
00118 
00119     template<typename _Rep, typename _Period>
00120       bool
00121       wait_for(unique_lock<mutex>& __lock,
00122            const chrono::duration<_Rep, _Period>& __rtime)
00123       { return wait_until(__lock, __clock_t::now() + __rtime); }
00124 
00125     template<typename _Rep, typename _Period, typename _Predicate>
00126       bool
00127       wait_for(unique_lock<mutex>& __lock,
00128            const chrono::duration<_Rep, _Period>& __rtime,
00129            _Predicate __p)
00130       { return wait_until(__lock, __clock_t::now() + __rtime, std::move(__p)); }
00131 
00132     native_handle_type
00133     native_handle()
00134     { return &_M_cond; }
00135 
00136   private:
00137     template<typename _Clock, typename _Duration>
00138       bool
00139       __wait_until_impl(unique_lock<mutex>& __lock,
00140             const chrono::time_point<_Clock, _Duration>& __atime)
00141       {
00142     chrono::time_point<__clock_t, chrono::seconds> __s =
00143       chrono::time_point_cast<chrono::seconds>(__atime);
00144 
00145     chrono::nanoseconds __ns =
00146       chrono::duration_cast<chrono::nanoseconds>(__atime - __s);
00147 
00148     __gthread_time_t __ts =
00149       {
00150         static_cast<std::time_t>(__s.time_since_epoch().count()),
00151         static_cast<long>(__ns.count())
00152       };
00153 
00154     __gthread_cond_timedwait(&_M_cond, __lock.mutex()->native_handle(),
00155                  &__ts);
00156 
00157     return _Clock::now() < __atime;
00158       }
00159   };
00160 
00161   /// condition_variable_any
00162   // Like above, only mutex may not have try_lock.
00163   class condition_variable_any
00164   {
00165     typedef __gthread_cond_t        __native_type;
00166     __native_type           _M_cond;
00167 
00168   public:
00169     typedef __native_type*      native_handle_type;
00170 
00171     condition_variable_any();
00172     ~condition_variable_any();
00173 
00174     condition_variable_any(const condition_variable_any&) = delete;
00175     condition_variable_any& operator=(const condition_variable_any&) = delete;
00176 
00177     void
00178     notify_one();
00179 
00180     void
00181     notify_all();
00182 
00183     template<typename _Lock>
00184       void
00185       wait(_Lock& __lock);
00186 
00187     template<typename _Lock, typename _Predicate>
00188       void
00189       wait(_Lock& __lock, _Predicate __p);
00190 
00191     template<typename _Lock, typename _Clock, typename _Duration>
00192       bool
00193       wait_until(_Lock& __lock,
00194          const chrono::time_point<_Clock, _Duration>& __atime);
00195 
00196     template<typename _Lock, typename _Clock,
00197          typename _Duration, typename _Predicate>
00198       bool
00199       wait_until(_Lock& __lock,
00200          const chrono::time_point<_Clock, _Duration>& __atime,
00201          _Predicate __p);
00202 
00203     template<typename _Lock, typename _Rep, typename _Period>
00204       bool
00205       wait_for(_Lock& __lock, const chrono::duration<_Rep, _Period>& __rtime);
00206 
00207     template<typename _Lock, typename _Rep,
00208          typename _Period, typename _Predicate>
00209       bool
00210       wait_for(_Lock& __lock,
00211            const chrono::duration<_Rep, _Period>& __rtime, _Predicate __p);
00212 
00213     native_handle_type
00214     native_handle()
00215     { return &_M_cond; }
00216   };
00217 
00218   // @} group condition_variables
00219 }
00220 
00221 #endif // _GLIBCXX_HAS_GTHREADS && _GLIBCXX_USE_C99_STDINT_TR1
00222 
00223 #endif // __GXX_EXPERIMENTAL_CXX0X__
00224 
00225 #endif // _GLIBCXX_CONDITION_VARIABLE

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