libstdc++
condition_variable
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00001 // <condition_variable> -*- C++ -*-
00002 
00003 // Copyright (C) 2008, 2009, 2010 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 #ifndef __GXX_EXPERIMENTAL_CXX0X__
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     __native_type           _M_cond;
00064 
00065   public:
00066     typedef __native_type*      native_handle_type;
00067 
00068     condition_variable() throw ();
00069     ~condition_variable() throw ();
00070 
00071     condition_variable(const condition_variable&) = delete;
00072     condition_variable& operator=(const condition_variable&) = delete;
00073 
00074     void
00075     notify_one();
00076 
00077     void
00078     notify_all();
00079 
00080     void
00081     wait(unique_lock<mutex>& __lock);
00082 
00083     template<typename _Predicate>
00084       void
00085       wait(unique_lock<mutex>& __lock, _Predicate __p)
00086       {
00087     while (!__p())
00088       wait(__lock);
00089       }
00090 
00091     template<typename _Duration>
00092       cv_status
00093       wait_until(unique_lock<mutex>& __lock,
00094          const chrono::time_point<__clock_t, _Duration>& __atime)
00095       { return __wait_until_impl(__lock, __atime); }
00096 
00097     template<typename _Clock, typename _Duration>
00098       cv_status
00099       wait_until(unique_lock<mutex>& __lock,
00100          const chrono::time_point<_Clock, _Duration>& __atime)
00101       {
00102     // DR 887 - Sync unknown clock to known clock.
00103     const typename _Clock::time_point __c_entry = _Clock::now();
00104     const __clock_t::time_point __s_entry = __clock_t::now();
00105     const chrono::nanoseconds __delta = __atime - __c_entry;
00106     const __clock_t::time_point __s_atime = __s_entry + __delta;
00107 
00108     return __wait_until_impl(__lock, __s_atime);
00109       }
00110 
00111     template<typename _Clock, typename _Duration, typename _Predicate>
00112       bool
00113       wait_until(unique_lock<mutex>& __lock,
00114          const chrono::time_point<_Clock, _Duration>& __atime,
00115          _Predicate __p)
00116       {
00117     while (!__p())
00118       if (wait_until(__lock, __atime) == cv_status::timeout)
00119         return __p();
00120     return true;
00121       }
00122 
00123     template<typename _Rep, typename _Period>
00124       cv_status
00125       wait_for(unique_lock<mutex>& __lock,
00126            const chrono::duration<_Rep, _Period>& __rtime)
00127       { return wait_until(__lock, __clock_t::now() + __rtime); }
00128 
00129     template<typename _Rep, typename _Period, typename _Predicate>
00130       bool
00131       wait_for(unique_lock<mutex>& __lock,
00132            const chrono::duration<_Rep, _Period>& __rtime,
00133            _Predicate __p)
00134       { return wait_until(__lock, __clock_t::now() + __rtime, std::move(__p)); }
00135 
00136     native_handle_type
00137     native_handle()
00138     { return &_M_cond; }
00139 
00140   private:
00141     template<typename _Clock, typename _Duration>
00142       cv_status
00143       __wait_until_impl(unique_lock<mutex>& __lock,
00144             const chrono::time_point<_Clock, _Duration>& __atime)
00145       {
00146     chrono::time_point<__clock_t, chrono::seconds> __s =
00147       chrono::time_point_cast<chrono::seconds>(__atime);
00148 
00149     chrono::nanoseconds __ns =
00150       chrono::duration_cast<chrono::nanoseconds>(__atime - __s);
00151 
00152     __gthread_time_t __ts =
00153       {
00154         static_cast<std::time_t>(__s.time_since_epoch().count()),
00155         static_cast<long>(__ns.count())
00156       };
00157 
00158     __gthread_cond_timedwait(&_M_cond, __lock.mutex()->native_handle(),
00159                  &__ts);
00160 
00161     return (_Clock::now() < __atime
00162         ? cv_status::no_timeout : cv_status::timeout);
00163       }
00164   };
00165 
00166   /// condition_variable_any
00167   // Like above, but mutex is not required to have try_lock.
00168   class condition_variable_any
00169   {
00170     typedef chrono::system_clock    __clock_t;
00171     condition_variable          _M_cond;
00172     mutex               _M_mutex;
00173 
00174   public:
00175     typedef condition_variable::native_handle_type  native_handle_type;
00176 
00177     condition_variable_any() throw ();
00178     ~condition_variable_any() throw ();
00179 
00180     condition_variable_any(const condition_variable_any&) = delete;
00181     condition_variable_any& operator=(const condition_variable_any&) = delete;
00182 
00183     void
00184     notify_one()
00185     {
00186       lock_guard<mutex> __lock(_M_mutex);
00187       _M_cond.notify_one();
00188     }
00189 
00190     void
00191     notify_all()
00192     {
00193       lock_guard<mutex> __lock(_M_mutex);
00194       _M_cond.notify_all();
00195     }
00196 
00197     template<typename _Lock>
00198       void
00199       wait(_Lock& __lock)
00200       {
00201         unique_lock<mutex> __my_lock(_M_mutex);
00202         __lock.unlock();
00203         _M_cond.wait(__my_lock);
00204         __lock.lock();
00205       }
00206       
00207 
00208     template<typename _Lock, typename _Predicate>
00209       void
00210       wait(_Lock& __lock, _Predicate __p)
00211       {
00212     while (!__p())
00213       wait(__lock);
00214       }
00215 
00216     template<typename _Lock, typename _Clock, typename _Duration>
00217       cv_status
00218       wait_until(_Lock& __lock,
00219          const chrono::time_point<_Clock, _Duration>& __atime)
00220       {
00221         unique_lock<mutex> __my_lock(_M_mutex);
00222         __lock.unlock();
00223         cv_status __status = _M_cond.wait_until(__my_lock, __atime);
00224         __lock.lock();
00225         return __status;
00226       }
00227 
00228     template<typename _Lock, typename _Clock,
00229          typename _Duration, typename _Predicate>
00230       bool
00231       wait_until(_Lock& __lock,
00232          const chrono::time_point<_Clock, _Duration>& __atime,
00233          _Predicate __p)
00234       {
00235     while (!__p())
00236       if (wait_until(__lock, __atime) == cv_status::timeout)
00237         return __p();
00238     return true;
00239       }
00240 
00241     template<typename _Lock, typename _Rep, typename _Period>
00242       cv_status
00243       wait_for(_Lock& __lock, const chrono::duration<_Rep, _Period>& __rtime)
00244       { return wait_until(__lock, __clock_t::now() + __rtime); }
00245 
00246     template<typename _Lock, typename _Rep,
00247          typename _Period, typename _Predicate>
00248       bool
00249       wait_for(_Lock& __lock,
00250            const chrono::duration<_Rep, _Period>& __rtime, _Predicate __p)
00251       { return wait_until(__lock, __clock_t::now() + __rtime, std::move(__p)); }
00252 
00253     native_handle_type
00254     native_handle()
00255     { return _M_cond.native_handle(); }
00256   };
00257 
00258   // @} group condition_variables
00259 _GLIBCXX_END_NAMESPACE_VERSION
00260 } // namespace
00261 
00262 #endif // _GLIBCXX_HAS_GTHREADS && _GLIBCXX_USE_C99_STDINT_TR1
00263 
00264 #endif // __GXX_EXPERIMENTAL_CXX0X__
00265 
00266 #endif // _GLIBCXX_CONDITION_VARIABLE