1 // condition_variable -*- C++ -*-
2 
3 // Copyright (C) 2008-2017 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 #include <condition_variable>
26 #include <cstdlib>
27 
28 #if defined(_GLIBCXX_HAS_GTHREADS) && defined(_GLIBCXX_USE_C99_STDINT_TR1)
29 
30 namespace std _GLIBCXX_VISIBILITY(default)
31 {
32 _GLIBCXX_BEGIN_NAMESPACE_VERSION
33 
34 #ifdef __GTHREAD_COND_INIT
35   condition_variable::condition_variable() noexcept = default;
36 #else
37   condition_variable::condition_variable() noexcept
38   {
39     __GTHREAD_COND_INIT_FUNCTION(&_M_cond);
40   }
41 #endif
42 
~condition_variable()43   condition_variable::~condition_variable() noexcept
44   {
45     // XXX no thread blocked
46     /* int __e = */ __gthread_cond_destroy(&_M_cond);
47     // if __e == EBUSY then blocked
48   }
49 
50   void
wait(unique_lock<mutex> & __lock)51   condition_variable::wait(unique_lock<mutex>& __lock) noexcept
52   {
53     int __e = __gthread_cond_wait(&_M_cond, __lock.mutex()->native_handle());
54 
55     if (__e)
56       std::terminate();
57   }
58 
59   void
notify_one()60   condition_variable::notify_one() noexcept
61   {
62     int __e = __gthread_cond_signal(&_M_cond);
63 
64     // XXX not in spec
65     // EINVAL
66     if (__e)
67       __throw_system_error(__e);
68   }
69 
70   void
notify_all()71   condition_variable::notify_all() noexcept
72   {
73     int __e = __gthread_cond_broadcast(&_M_cond);
74 
75     // XXX not in spec
76     // EINVAL
77     if (__e)
78       __throw_system_error(__e);
79   }
80 
81   extern void
82   __at_thread_exit(__at_thread_exit_elt*);
83 
84   namespace
85   {
86     __gthread_key_t key;
87 
run(void * p)88     void run(void* p)
89     {
90       auto elt = (__at_thread_exit_elt*)p;
91       while (elt)
92 	{
93 	  auto next = elt->_M_next;
94 	  elt->_M_cb(elt);
95 	  elt = next;
96 	}
97     }
98 
run()99     void run()
100     {
101       auto elt = (__at_thread_exit_elt*)__gthread_getspecific(key);
102       __gthread_setspecific(key, nullptr);
103       run(elt);
104     }
105 
106     struct notifier final : __at_thread_exit_elt
107     {
notifierstd::__anon2aa1de100111::notifier108       notifier(condition_variable& cv, unique_lock<mutex>& l)
109       : cv(&cv), mx(l.release())
110       {
111 	_M_cb = &notifier::run;
112 	__at_thread_exit(this);
113       }
114 
~notifierstd::__anon2aa1de100111::notifier115       ~notifier()
116       {
117 	mx->unlock();
118 	cv->notify_all();
119       }
120 
121       condition_variable* cv;
122       mutex* mx;
123 
runstd::__anon2aa1de100111::notifier124       static void run(void* p) { delete static_cast<notifier*>(p); }
125     };
126 
127 
key_init()128     void key_init() {
129       struct key_s {
130 	key_s() { __gthread_key_create (&key, run); }
131 	~key_s() { __gthread_key_delete (key); }
132       };
133       static key_s ks;
134       // Also make sure the callbacks are run by std::exit.
135       std::atexit (run);
136     }
137   }
138 
139   void
__at_thread_exit(__at_thread_exit_elt * elt)140   __at_thread_exit(__at_thread_exit_elt* elt)
141   {
142     static __gthread_once_t once = __GTHREAD_ONCE_INIT;
143     __gthread_once (&once, key_init);
144 
145     elt->_M_next = (__at_thread_exit_elt*)__gthread_getspecific(key);
146     __gthread_setspecific(key, elt);
147   }
148 
149   void
notify_all_at_thread_exit(condition_variable & cv,unique_lock<mutex> l)150   notify_all_at_thread_exit(condition_variable& cv, unique_lock<mutex> l)
151   {
152     (void) new notifier{cv, l};
153   }
154 
155 _GLIBCXX_END_NAMESPACE_VERSION
156 } // namespace
157 
158 #endif // _GLIBCXX_HAS_GTHREADS && _GLIBCXX_USE_C99_STDINT_TR1
159