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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 :
49 : namespace 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 2563 : wait(unique_lock<mutex>& __lock, _Predicate __p)
97 : {
98 2563 : while (!__p())
99 1730 : wait(__lock);
100 833 : }
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
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