1// <condition_variable> -*- C++ -*-
2
3// Copyright (C) 2008, 2009, 2010, 2011, 2012 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
43namespace 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 auto __delta = __atime - __c_entry;
111	const auto __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    // scoped unlock - unlocks in ctor, re-locks in dtor
180    template<typename _Lock>
181      struct _Unlock
182      {
183	explicit _Unlock(_Lock& __lk) : _M_lock(__lk) { __lk.unlock(); }
184
185	~_Unlock() noexcept(false)
186	{
187	  if (uncaught_exception())
188	    __try { _M_lock.lock(); } __catch(...) { }
189	  else
190	    _M_lock.lock();
191	}
192
193	_Unlock(const _Unlock&) = delete;
194	_Unlock& operator=(const _Unlock&) = delete;
195
196	_Lock& _M_lock;
197      };
198
199  public:
200
201    condition_variable_any() noexcept;
202    ~condition_variable_any() noexcept;
203
204    condition_variable_any(const condition_variable_any&) = delete;
205    condition_variable_any& operator=(const condition_variable_any&) = delete;
206
207    void
208    notify_one() noexcept
209    {
210      lock_guard<mutex> __lock(_M_mutex);
211      _M_cond.notify_one();
212    }
213
214    void
215    notify_all() noexcept
216    {
217      lock_guard<mutex> __lock(_M_mutex);
218      _M_cond.notify_all();
219    }
220
221    template<typename _Lock>
222      void
223      wait(_Lock& __lock)
224      {
225	unique_lock<mutex> __my_lock(_M_mutex);
226	_Unlock<_Lock> __unlock(__lock);
227	// _M_mutex must be unlocked before re-locking __lock so move
228	// ownership of _M_mutex lock to an object with shorter lifetime.
229	unique_lock<mutex> __my_lock2(std::move(__my_lock));
230	_M_cond.wait(__my_lock2);
231      }
232
233
234    template<typename _Lock, typename _Predicate>
235      void
236      wait(_Lock& __lock, _Predicate __p)
237      {
238	while (!__p())
239	  wait(__lock);
240      }
241
242    template<typename _Lock, typename _Clock, typename _Duration>
243      cv_status
244      wait_until(_Lock& __lock,
245		 const chrono::time_point<_Clock, _Duration>& __atime)
246      {
247	unique_lock<mutex> __my_lock(_M_mutex);
248	_Unlock<_Lock> __unlock(__lock);
249	// _M_mutex must be unlocked before re-locking __lock so move
250	// ownership of _M_mutex lock to an object with shorter lifetime.
251	unique_lock<mutex> __my_lock2(std::move(__my_lock));
252	return _M_cond.wait_until(__my_lock2, __atime);
253      }
254
255    template<typename _Lock, typename _Clock,
256	     typename _Duration, typename _Predicate>
257      bool
258      wait_until(_Lock& __lock,
259		 const chrono::time_point<_Clock, _Duration>& __atime,
260		 _Predicate __p)
261      {
262	while (!__p())
263	  if (wait_until(__lock, __atime) == cv_status::timeout)
264	    return __p();
265	return true;
266      }
267
268    template<typename _Lock, typename _Rep, typename _Period>
269      cv_status
270      wait_for(_Lock& __lock, const chrono::duration<_Rep, _Period>& __rtime)
271      { return wait_until(__lock, __clock_t::now() + __rtime); }
272
273    template<typename _Lock, typename _Rep,
274	     typename _Period, typename _Predicate>
275      bool
276      wait_for(_Lock& __lock,
277	       const chrono::duration<_Rep, _Period>& __rtime, _Predicate __p)
278      { return wait_until(__lock, __clock_t::now() + __rtime, std::move(__p)); }
279  };
280
281  // @} group condition_variables
282_GLIBCXX_END_NAMESPACE_VERSION
283} // namespace
284
285#endif // _GLIBCXX_HAS_GTHREADS && _GLIBCXX_USE_C99_STDINT_TR1
286
287#endif // __GXX_EXPERIMENTAL_CXX0X__
288
289#endif // _GLIBCXX_CONDITION_VARIABLE
290