# 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 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
    00044 {
    00045   /**
    00046    * @defgroup condition_variables Condition Variables
    00047    * @ingroup concurrency
    00048    *
    00049    * Classes for condition_variable support.
    00050    * @{
    00051    */
    00052
    00053   /// cv_status
    00054   enum class cv_status { no_timeout, timeout };
    00055
    00056   /// condition_variable
    00057   class condition_variable
    00058   {
    00059     typedef chrono::system_clock    __clock_t;
    00060     typedef __gthread_cond_t        __native_type;
    00061     __native_type           _M_cond;
    00062
    00063   public:
    00064     typedef __native_type*      native_handle_type;
    00065
    00066     condition_variable() throw ();
    00067     ~condition_variable() throw ();
    00068
    00069     condition_variable(const condition_variable&) = delete;
    00070     condition_variable& operator=(const condition_variable&) = delete;
    00071
    00072     void
    00073     notify_one();
    00074
    00075     void
    00076     notify_all();
    00077
    00078     void
    00079     wait(unique_lock<mutex>& __lock);
    00080
    00081     template<typename _Predicate>
    00082       void
    00083       wait(unique_lock<mutex>& __lock, _Predicate __p)
    00084       {
    00085     while (!__p())
    00086       wait(__lock);
    00087       }
    00088
    00089     template<typename _Duration>
    00090       cv_status
    00091       wait_until(unique_lock<mutex>& __lock,
    00092          const chrono::time_point<__clock_t, _Duration>& __atime)
    00093       { return __wait_until_impl(__lock, __atime); }
    00094
    00095     template<typename _Clock, typename _Duration>
    00096       cv_status
    00097       wait_until(unique_lock<mutex>& __lock,
    00098          const chrono::time_point<_Clock, _Duration>& __atime)
    00099       {
    00100     // DR 887 - Sync unknown clock to known clock.
    00101     const typename _Clock::time_point __c_entry = _Clock::now();
    00102     const __clock_t::time_point __s_entry = __clock_t::now();
    00103     const chrono::nanoseconds __delta = __atime - __c_entry;
    00104     const __clock_t::time_point __s_atime = __s_entry + __delta;
    00105
    00106     return __wait_until_impl(__lock, __s_atime);
    00107       }
    00108
    00109     template<typename _Clock, typename _Duration, typename _Predicate>
    00110       bool
    00111       wait_until(unique_lock<mutex>& __lock,
    00112          const chrono::time_point<_Clock, _Duration>& __atime,
    00113          _Predicate __p)
    00114       {
    00115     while (!__p())
    00116       if (wait_until(__lock, __atime) == cv_status::timeout)
    00117         return __p();
    00118     return true;
    00119       }
    00120
    00121     template<typename _Rep, typename _Period>
    00122       cv_status
    00123       wait_for(unique_lock<mutex>& __lock,
    00124            const chrono::duration<_Rep, _Period>& __rtime)
    00125       { return wait_until(__lock, __clock_t::now() + __rtime); }
    00126
    00127     template<typename _Rep, typename _Period, typename _Predicate>
    00128       bool
    00129       wait_for(unique_lock<mutex>& __lock,
    00130            const chrono::duration<_Rep, _Period>& __rtime,
    00131            _Predicate __p)
    00132       { return wait_until(__lock, __clock_t::now() + __rtime, std::move(__p)); }
    00133
    00134     native_handle_type
    00135     native_handle()
    00136     { return &_M_cond; }
    00137
    00138   private:
    00139     template<typename _Clock, typename _Duration>
    00140       cv_status
    00141       __wait_until_impl(unique_lock<mutex>& __lock,
    00142             const chrono::time_point<_Clock, _Duration>& __atime)
    00143       {
    00144     chrono::time_point<__clock_t, chrono::seconds> __s =
    00145       chrono::time_point_cast<chrono::seconds>(__atime);
    00146
    00147     chrono::nanoseconds __ns =
    00148       chrono::duration_cast<chrono::nanoseconds>(__atime - __s);
    00149
    00150     __gthread_time_t __ts =
    00151       {
    00152         static_cast<std::time_t>(__s.time_since_epoch().count()),
    00153         static_cast<long>(__ns.count())
    00154       };
    00155
    00156     __gthread_cond_timedwait(&_M_cond, __lock.mutex()->native_handle(),
    00157                  &__ts);
    00158
    00159     return (_Clock::now() < __atime
    00160         ? cv_status::no_timeout : cv_status::timeout);
    00161       }
    00162   };
    00163
    00164   /// condition_variable_any
    00165   // Like above, but mutex is not required to have try_lock.
    00166   class condition_variable_any
    00167   {
    00168     typedef chrono::system_clock    __clock_t;
    00169     condition_variable          _M_cond;
    00170     mutex               _M_mutex;
    00171
    00172   public:
    00173     typedef condition_variable::native_handle_type  native_handle_type;
    00174
    00175     condition_variable_any() throw ();
    00176     ~condition_variable_any() throw ();
    00177
    00178     condition_variable_any(const condition_variable_any&) = delete;
    00179     condition_variable_any& operator=(const condition_variable_any&) = delete;
    00180
    00181     void
    00182     notify_one()
    00183     {
    00184       lock_guard<mutex> __lock(_M_mutex);
    00185       _M_cond.notify_one();
    00186     }
    00187
    00188     void
    00189     notify_all()
    00190     {
    00191       lock_guard<mutex> __lock(_M_mutex);
    00192       _M_cond.notify_all();
    00193     }
    00194
    00195     template<typename _Lock>
    00196       void
    00197       wait(_Lock& __lock)
    00198       {
    00199         unique_lock<mutex> __my_lock(_M_mutex);
    00200         __lock.unlock();
    00201         _M_cond.wait(__my_lock);
    00202         __lock.lock();
    00203       }
    00204
    00205
    00206     template<typename _Lock, typename _Predicate>
    00207       void
    00208       wait(_Lock& __lock, _Predicate __p)
    00209       {
    00210     while (!__p())
    00211       wait(__lock);
    00212       }
    00213
    00214     template<typename _Lock, typename _Clock, typename _Duration>
    00215       cv_status
    00216       wait_until(_Lock& __lock,
    00217          const chrono::time_point<_Clock, _Duration>& __atime)
    00218       {
    00219         unique_lock<mutex> __my_lock(_M_mutex);
    00220         __lock.unlock();
    00221         cv_status __status = _M_cond.wait_until(__my_lock, __atime);
    00222         __lock.lock();
    00223         return __status;
    00224       }
    00225
    00226     template<typename _Lock, typename _Clock,
    00227          typename _Duration, typename _Predicate>
    00228       bool
    00229       wait_until(_Lock& __lock,
    00230          const chrono::time_point<_Clock, _Duration>& __atime,
    00231          _Predicate __p)
    00232       {
    00233     while (!__p())
    00234       if (wait_until(__lock, __atime) == cv_status::timeout)
    00235         return __p();
    00236     return true;
    00237       }
    00238
    00239     template<typename _Lock, typename _Rep, typename _Period>
    00240       cv_status
    00241       wait_for(_Lock& __lock, const chrono::duration<_Rep, _Period>& __rtime)
    00242       { return wait_until(__lock, __clock_t::now() + __rtime); }
    00243
    00244     template<typename _Lock, typename _Rep,
    00245          typename _Period, typename _Predicate>
    00246       bool
    00247       wait_for(_Lock& __lock,
    00248            const chrono::duration<_Rep, _Period>& __rtime, _Predicate __p)
    00249       { return wait_until(__lock, __clock_t::now() + __rtime, std::move(__p)); }
    00250
    00251     native_handle_type
    00252     native_handle()
    00253     { return _M_cond.native_handle(); }
    00254   };
    00255
    00256   // @} group condition_variables
    00257 }
    00258
    00259 #endif // _GLIBCXX_HAS_GTHREADS && _GLIBCXX_USE_C99_STDINT_TR1
    00260
    00261 #endif // __GXX_EXPERIMENTAL_CXX0X__
    00262
    00263 #endif // _GLIBCXX_CONDITION_VARIABLE