1// <condition_variable> -*- C++ -*-
2
3// Copyright (C) 2008-2018 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#if __cplusplus < 201103L
35# include <bits/c++0x_warning.h>
36#else
37
38#include <chrono>
39#include <bits/std_mutex.h>
40#include <ext/concurrence.h>
41#include <bits/alloc_traits.h>
42#include <bits/allocator.h>
43#include <bits/unique_ptr.h>
44#include <bits/shared_ptr.h>
45#include <bits/cxxabi_forced.h>
46
47#if defined(_GLIBCXX_HAS_GTHREADS) && defined(_GLIBCXX_USE_C99_STDINT_TR1)
48
49namespace std _GLIBCXX_VISIBILITY(default)
50{
51_GLIBCXX_BEGIN_NAMESPACE_VERSION
52
53  /**
54   * @defgroup condition_variables Condition Variables
55   * @ingroup concurrency
56   *
57   * Classes for condition_variable support.
58   * @{
59   */
60
61  /// cv_status
62  enum class cv_status { no_timeout, timeout };
63
64  /// condition_variable
65  class condition_variable
66  {
67    typedef chrono::system_clock	__clock_t;
68    typedef __gthread_cond_t		__native_type;
69
70#ifdef __GTHREAD_COND_INIT
71    __native_type			_M_cond = __GTHREAD_COND_INIT;
72#else
73    __native_type			_M_cond;
74#endif
75
76  public:
77    typedef __native_type* 		native_handle_type;
78
79    condition_variable() noexcept;
80    ~condition_variable() noexcept;
81
82    condition_variable(const condition_variable&) = delete;
83    condition_variable& operator=(const condition_variable&) = delete;
84
85    void
86    notify_one() noexcept;
87
88    void
89    notify_all() noexcept;
90
91    void
92    wait(unique_lock<mutex>& __lock) noexcept;
93
94    template<typename _Predicate>
95      void
96      wait(unique_lock<mutex>& __lock, _Predicate __p)
97      {
98	while (!__p())
99	  wait(__lock);
100      }
101
102    template<typename _Duration>
103      cv_status
104      wait_until(unique_lock<mutex>& __lock,
105		 const chrono::time_point<__clock_t, _Duration>& __atime)
106      { return __wait_until_impl(__lock, __atime); }
107
108    template<typename _Clock, typename _Duration>
109      cv_status
110      wait_until(unique_lock<mutex>& __lock,
111		 const chrono::time_point<_Clock, _Duration>& __atime)
112      {
113	// DR 887 - Sync unknown clock to known clock.
114	const typename _Clock::time_point __c_entry = _Clock::now();
115	const __clock_t::time_point __s_entry = __clock_t::now();
116	const auto __delta = __atime - __c_entry;
117	const auto __s_atime = __s_entry + __delta;
118
119	return __wait_until_impl(__lock, __s_atime);
120      }
121
122    template<typename _Clock, typename _Duration, typename _Predicate>
123      bool
124      wait_until(unique_lock<mutex>& __lock,
125		 const chrono::time_point<_Clock, _Duration>& __atime,
126		 _Predicate __p)
127      {
128	while (!__p())
129	  if (wait_until(__lock, __atime) == cv_status::timeout)
130	    return __p();
131	return true;
132      }
133
134    template<typename _Rep, typename _Period>
135      cv_status
136      wait_for(unique_lock<mutex>& __lock,
137	       const chrono::duration<_Rep, _Period>& __rtime)
138      {
139	using __dur = typename __clock_t::duration;
140	auto __reltime = chrono::duration_cast<__dur>(__rtime);
141	if (__reltime < __rtime)
142	  ++__reltime;
143	return wait_until(__lock, __clock_t::now() + __reltime);
144      }
145
146    template<typename _Rep, typename _Period, typename _Predicate>
147      bool
148      wait_for(unique_lock<mutex>& __lock,
149	       const chrono::duration<_Rep, _Period>& __rtime,
150	       _Predicate __p)
151      {
152	using __dur = typename __clock_t::duration;
153	auto __reltime = chrono::duration_cast<__dur>(__rtime);
154	if (__reltime < __rtime)
155	  ++__reltime;
156	return wait_until(__lock, __clock_t::now() + __reltime, std::move(__p));
157      }
158
159    native_handle_type
160    native_handle()
161    { return &_M_cond; }
162
163  private:
164    template<typename _Dur>
165      cv_status
166      __wait_until_impl(unique_lock<mutex>& __lock,
167			const chrono::time_point<__clock_t, _Dur>& __atime)
168      {
169	auto __s = chrono::time_point_cast<chrono::seconds>(__atime);
170	auto __ns = chrono::duration_cast<chrono::nanoseconds>(__atime - __s);
171
172	__gthread_time_t __ts =
173	  {
174	    static_cast<std::time_t>(__s.time_since_epoch().count()),
175	    static_cast<long>(__ns.count())
176	  };
177
178	__gthread_cond_timedwait(&_M_cond, __lock.mutex()->native_handle(),
179				 &__ts);
180
181	return (__clock_t::now() < __atime
182		? cv_status::no_timeout : cv_status::timeout);
183      }
184  };
185
186  void
187  notify_all_at_thread_exit(condition_variable&, unique_lock<mutex>);
188
189  struct __at_thread_exit_elt
190  {
191    __at_thread_exit_elt* _M_next;
192    void (*_M_cb)(void*);
193  };
194
195  inline namespace _V2 {
196
197  /// condition_variable_any
198  // Like above, but mutex is not required to have try_lock.
199  class condition_variable_any
200  {
201    typedef chrono::system_clock	__clock_t;
202    condition_variable			_M_cond;
203    shared_ptr<mutex>			_M_mutex;
204
205    // scoped unlock - unlocks in ctor, re-locks in dtor
206    template<typename _Lock>
207      struct _Unlock
208      {
209	explicit _Unlock(_Lock& __lk) : _M_lock(__lk) { __lk.unlock(); }
210
211	~_Unlock() noexcept(false)
212	{
213	  if (uncaught_exception())
214	    {
215	      __try
216	      { _M_lock.lock(); }
217	      __catch(const __cxxabiv1::__forced_unwind&)
218	      { __throw_exception_again; }
219	      __catch(...)
220	      { }
221	    }
222	  else
223	    _M_lock.lock();
224	}
225
226	_Unlock(const _Unlock&) = delete;
227	_Unlock& operator=(const _Unlock&) = delete;
228
229	_Lock& _M_lock;
230      };
231
232  public:
233    condition_variable_any() : _M_mutex(std::make_shared<mutex>()) { }
234    ~condition_variable_any() = default;
235
236    condition_variable_any(const condition_variable_any&) = delete;
237    condition_variable_any& operator=(const condition_variable_any&) = delete;
238
239    void
240    notify_one() noexcept
241    {
242      lock_guard<mutex> __lock(*_M_mutex);
243      _M_cond.notify_one();
244    }
245
246    void
247    notify_all() noexcept
248    {
249      lock_guard<mutex> __lock(*_M_mutex);
250      _M_cond.notify_all();
251    }
252
253    template<typename _Lock>
254      void
255      wait(_Lock& __lock)
256      {
257	shared_ptr<mutex> __mutex = _M_mutex;
258	unique_lock<mutex> __my_lock(*__mutex);
259	_Unlock<_Lock> __unlock(__lock);
260	// *__mutex must be unlocked before re-locking __lock so move
261	// ownership of *__mutex lock to an object with shorter lifetime.
262	unique_lock<mutex> __my_lock2(std::move(__my_lock));
263	_M_cond.wait(__my_lock2);
264      }
265
266
267    template<typename _Lock, typename _Predicate>
268      void
269      wait(_Lock& __lock, _Predicate __p)
270      {
271	while (!__p())
272	  wait(__lock);
273      }
274
275    template<typename _Lock, typename _Clock, typename _Duration>
276      cv_status
277      wait_until(_Lock& __lock,
278		 const chrono::time_point<_Clock, _Duration>& __atime)
279      {
280	shared_ptr<mutex> __mutex = _M_mutex;
281	unique_lock<mutex> __my_lock(*__mutex);
282	_Unlock<_Lock> __unlock(__lock);
283	// *__mutex must be unlocked before re-locking __lock so move
284	// ownership of *__mutex lock to an object with shorter lifetime.
285	unique_lock<mutex> __my_lock2(std::move(__my_lock));
286	return _M_cond.wait_until(__my_lock2, __atime);
287      }
288
289    template<typename _Lock, typename _Clock,
290	     typename _Duration, typename _Predicate>
291      bool
292      wait_until(_Lock& __lock,
293		 const chrono::time_point<_Clock, _Duration>& __atime,
294		 _Predicate __p)
295      {
296	while (!__p())
297	  if (wait_until(__lock, __atime) == cv_status::timeout)
298	    return __p();
299	return true;
300      }
301
302    template<typename _Lock, typename _Rep, typename _Period>
303      cv_status
304      wait_for(_Lock& __lock, const chrono::duration<_Rep, _Period>& __rtime)
305      { return wait_until(__lock, __clock_t::now() + __rtime); }
306
307    template<typename _Lock, typename _Rep,
308	     typename _Period, typename _Predicate>
309      bool
310      wait_for(_Lock& __lock,
311	       const chrono::duration<_Rep, _Period>& __rtime, _Predicate __p)
312      { return wait_until(__lock, __clock_t::now() + __rtime, std::move(__p)); }
313  };
314
315  } // end inline namespace
316
317  // @} group condition_variables
318_GLIBCXX_END_NAMESPACE_VERSION
319} // namespace
320
321#endif // _GLIBCXX_HAS_GTHREADS && _GLIBCXX_USE_C99_STDINT_TR1
322
323#endif // C++11
324
325#endif // _GLIBCXX_CONDITION_VARIABLE
326