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