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1 // <condition_variable> -*- C++ -*-
2
3 // Copyright (C) 2008, 2009, 2010 Free Software Foundation, Inc.
4 //
5 // This file is part of the GNU ISO C++ Library.  This library is free
6 // software; you can redistribute it and/or modify it under the
7 // terms of the GNU General Public License as published by the
8 // Free Software Foundation; either version 3, or (at your option)
9 // any later version.
10
11 // This library is distributed in the hope that it will be useful,
12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14 // GNU General Public License for more details.
15
16 // Under Section 7 of GPL version 3, you are granted additional
17 // permissions described in the GCC Runtime Library Exception, version
18 // 3.1, as published by the Free Software Foundation.
19
20 // You should have received a copy of the GNU General Public License and
21 // a copy of the GCC Runtime Library Exception along with this program;
22 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
23 // <http://www.gnu.org/licenses/>.
24
25 /** @file include/condition_variable
26  *  This is a Standard C++ Library header.
27  */
28
29 #ifndef _GLIBCXX_CONDITION_VARIABLE
30 #define _GLIBCXX_CONDITION_VARIABLE 1
31
32 #pragma GCC system_header
33
34 #ifndef __GXX_EXPERIMENTAL_CXX0X__
35 # include <bits/c++0x_warning.h>
36 #else
37
38 #include <chrono>
39 #include <mutex> // unique_lock
40
41 #if defined(_GLIBCXX_HAS_GTHREADS) && defined(_GLIBCXX_USE_C99_STDINT_TR1)
42
43 namespace std _GLIBCXX_VISIBILITY(default)
44 {
45 _GLIBCXX_BEGIN_NAMESPACE_VERSION
46
47   /**
48    * @defgroup condition_variables Condition Variables
49    * @ingroup concurrency
50    *
51    * Classes for condition_variable support.
52    * @{
53    */
54
55   /// cv_status
56   enum class cv_status { no_timeout, timeout };
57   
58   /// condition_variable
59   class condition_variable
60   {
61     typedef chrono::system_clock        __clock_t;
62     typedef __gthread_cond_t            __native_type;
63
64 #ifdef __GTHREAD_COND_INIT
65     __native_type                       _M_cond = __GTHREAD_COND_INIT;
66 #else
67     __native_type                       _M_cond;
68 #endif
69
70   public:
71     typedef __native_type*              native_handle_type;
72
73     condition_variable() noexcept;
74     ~condition_variable() noexcept;
75
76     condition_variable(const condition_variable&) = delete;
77     condition_variable& operator=(const condition_variable&) = delete;
78
79     void
80     notify_one() noexcept;
81
82     void
83     notify_all() noexcept;
84
85     void
86     wait(unique_lock<mutex>& __lock);
87
88     template<typename _Predicate>
89       void
90       wait(unique_lock<mutex>& __lock, _Predicate __p)
91       {
92         while (!__p())
93           wait(__lock);
94       }
95
96     template<typename _Duration>
97       cv_status
98       wait_until(unique_lock<mutex>& __lock,
99                  const chrono::time_point<__clock_t, _Duration>& __atime)
100       { return __wait_until_impl(__lock, __atime); }
101
102     template<typename _Clock, typename _Duration>
103       cv_status
104       wait_until(unique_lock<mutex>& __lock,
105                  const chrono::time_point<_Clock, _Duration>& __atime)
106       {
107         // DR 887 - Sync unknown clock to known clock.
108         const typename _Clock::time_point __c_entry = _Clock::now();
109         const __clock_t::time_point __s_entry = __clock_t::now();
110         const chrono::nanoseconds __delta = __atime - __c_entry;
111         const __clock_t::time_point __s_atime = __s_entry + __delta;
112
113         return __wait_until_impl(__lock, __s_atime);
114       }
115
116     template<typename _Clock, typename _Duration, typename _Predicate>
117       bool
118       wait_until(unique_lock<mutex>& __lock,
119                  const chrono::time_point<_Clock, _Duration>& __atime,
120                  _Predicate __p)
121       {
122         while (!__p())
123           if (wait_until(__lock, __atime) == cv_status::timeout)
124             return __p();
125         return true;
126       }
127
128     template<typename _Rep, typename _Period>
129       cv_status
130       wait_for(unique_lock<mutex>& __lock,
131                const chrono::duration<_Rep, _Period>& __rtime)
132       { return wait_until(__lock, __clock_t::now() + __rtime); }
133
134     template<typename _Rep, typename _Period, typename _Predicate>
135       bool
136       wait_for(unique_lock<mutex>& __lock,
137                const chrono::duration<_Rep, _Period>& __rtime,
138                _Predicate __p)
139       { return wait_until(__lock, __clock_t::now() + __rtime, std::move(__p)); }
140
141     native_handle_type
142     native_handle()
143     { return &_M_cond; }
144
145   private:
146     template<typename _Clock, typename _Duration>
147       cv_status
148       __wait_until_impl(unique_lock<mutex>& __lock,
149                         const chrono::time_point<_Clock, _Duration>& __atime)
150       {
151         chrono::time_point<__clock_t, chrono::seconds> __s =
152           chrono::time_point_cast<chrono::seconds>(__atime);
153
154         chrono::nanoseconds __ns =
155           chrono::duration_cast<chrono::nanoseconds>(__atime - __s);
156
157         __gthread_time_t __ts =
158           {
159             static_cast<std::time_t>(__s.time_since_epoch().count()),
160             static_cast<long>(__ns.count())
161           };
162
163         __gthread_cond_timedwait(&_M_cond, __lock.mutex()->native_handle(),
164                                  &__ts);
165
166         return (_Clock::now() < __atime
167                 ? cv_status::no_timeout : cv_status::timeout);
168       }
169   };
170
171   /// condition_variable_any
172   // Like above, but mutex is not required to have try_lock.
173   class condition_variable_any
174   {
175     typedef chrono::system_clock        __clock_t;
176     condition_variable                  _M_cond;
177     mutex                               _M_mutex;
178
179   public:
180     typedef condition_variable::native_handle_type      native_handle_type;
181
182     condition_variable_any() noexcept;
183     ~condition_variable_any() noexcept;
184
185     condition_variable_any(const condition_variable_any&) = delete;
186     condition_variable_any& operator=(const condition_variable_any&) = delete;
187
188     void
189     notify_one() noexcept
190     {
191       lock_guard<mutex> __lock(_M_mutex);
192       _M_cond.notify_one();
193     }
194
195     void
196     notify_all() noexcept
197     {
198       lock_guard<mutex> __lock(_M_mutex);
199       _M_cond.notify_all();
200     }
201
202     template<typename _Lock>
203       void
204       wait(_Lock& __lock)
205       {
206         unique_lock<mutex> __my_lock(_M_mutex);
207         __lock.unlock();
208         _M_cond.wait(__my_lock);
209         __lock.lock();
210       }
211       
212
213     template<typename _Lock, typename _Predicate>
214       void
215       wait(_Lock& __lock, _Predicate __p)
216       {
217         while (!__p())
218           wait(__lock);
219       }
220
221     template<typename _Lock, typename _Clock, typename _Duration>
222       cv_status
223       wait_until(_Lock& __lock,
224                  const chrono::time_point<_Clock, _Duration>& __atime)
225       {
226         unique_lock<mutex> __my_lock(_M_mutex);
227         __lock.unlock();
228         cv_status __status = _M_cond.wait_until(__my_lock, __atime);
229         __lock.lock();
230         return __status;
231       }
232
233     template<typename _Lock, typename _Clock,
234              typename _Duration, typename _Predicate>
235       bool
236       wait_until(_Lock& __lock,
237                  const chrono::time_point<_Clock, _Duration>& __atime,
238                  _Predicate __p)
239       {
240         while (!__p())
241           if (wait_until(__lock, __atime) == cv_status::timeout)
242             return __p();
243         return true;
244       }
245
246     template<typename _Lock, typename _Rep, typename _Period>
247       cv_status
248       wait_for(_Lock& __lock, const chrono::duration<_Rep, _Period>& __rtime)
249       { return wait_until(__lock, __clock_t::now() + __rtime); }
250
251     template<typename _Lock, typename _Rep,
252              typename _Period, typename _Predicate>
253       bool
254       wait_for(_Lock& __lock,
255                const chrono::duration<_Rep, _Period>& __rtime, _Predicate __p)
256       { return wait_until(__lock, __clock_t::now() + __rtime, std::move(__p)); }
257
258     native_handle_type
259     native_handle()
260     { return _M_cond.native_handle(); }
261   };
262
263   // @} group condition_variables
264 _GLIBCXX_END_NAMESPACE_VERSION
265 } // namespace
266
267 #endif // _GLIBCXX_HAS_GTHREADS && _GLIBCXX_USE_C99_STDINT_TR1
268
269 #endif // __GXX_EXPERIMENTAL_CXX0X__
270
271 #endif // _GLIBCXX_CONDITION_VARIABLE