xref: /freebsd/contrib/llvm-project/libcxx/src/condition_variable.cpp (revision 0fca6ea1d4eea4c934cfff25ac9ee8ad6fe95583)
1 //===----------------------------------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include <condition_variable>
10 #include <thread>
11 
12 #if defined(__ELF__) && defined(_LIBCPP_LINK_PTHREAD_LIB)
13 #  pragma comment(lib, "pthread")
14 #endif
15 
16 _LIBCPP_PUSH_MACROS
17 #include <__undef_macros>
18 
19 _LIBCPP_BEGIN_NAMESPACE_STD
20 
21 // ~condition_variable is defined elsewhere.
22 
23 void condition_variable::notify_one() noexcept { __libcpp_condvar_signal(&__cv_); }
24 
25 void condition_variable::notify_all() noexcept { __libcpp_condvar_broadcast(&__cv_); }
26 
27 void condition_variable::wait(unique_lock<mutex>& lk) noexcept {
28   if (!lk.owns_lock())
29     __throw_system_error(EPERM, "condition_variable::wait: mutex not locked");
30   int ec = __libcpp_condvar_wait(&__cv_, lk.mutex()->native_handle());
31   if (ec)
32     __throw_system_error(ec, "condition_variable wait failed");
33 }
34 
35 void condition_variable::__do_timed_wait(unique_lock<mutex>& lk,
36                                          chrono::time_point<chrono::system_clock, chrono::nanoseconds> tp) noexcept {
37   using namespace chrono;
38   if (!lk.owns_lock())
39     __throw_system_error(EPERM, "condition_variable::timed wait: mutex not locked");
40   nanoseconds d = tp.time_since_epoch();
41   if (d > nanoseconds(0x59682F000000E941))
42     d = nanoseconds(0x59682F000000E941);
43   __libcpp_timespec_t ts;
44   seconds s = duration_cast<seconds>(d);
45   typedef decltype(ts.tv_sec) ts_sec;
46   constexpr ts_sec ts_sec_max = numeric_limits<ts_sec>::max();
47   if (s.count() < ts_sec_max) {
48     ts.tv_sec  = static_cast<ts_sec>(s.count());
49     ts.tv_nsec = static_cast<decltype(ts.tv_nsec)>((d - s).count());
50   } else {
51     ts.tv_sec  = ts_sec_max;
52     ts.tv_nsec = giga::num - 1;
53   }
54   int ec = __libcpp_condvar_timedwait(&__cv_, lk.mutex()->native_handle(), &ts);
55   if (ec != 0 && ec != ETIMEDOUT)
56     __throw_system_error(ec, "condition_variable timed_wait failed");
57 }
58 
59 void notify_all_at_thread_exit(condition_variable& cond, unique_lock<mutex> lk) {
60   auto& tl_ptr = __thread_local_data();
61   // If this thread was not created using std::thread then it will not have
62   // previously allocated.
63   if (tl_ptr.get() == nullptr) {
64     tl_ptr.set_pointer(new __thread_struct);
65   }
66   __thread_local_data()->notify_all_at_thread_exit(&cond, lk.release());
67 }
68 
69 _LIBCPP_END_NAMESPACE_STD
70 
71 _LIBCPP_POP_MACROS
72