xref: /freebsd/contrib/llvm-project/libcxx/src/condition_variable.cpp (revision 18054d0220cfc8df9c9568c437bd6fbb59d53c3c)
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 "__config"
10 
11 #ifndef _LIBCPP_HAS_NO_THREADS
12 
13 #include "condition_variable"
14 #include "thread"
15 #include "system_error"
16 #include "__undef_macros"
17 
18 #if defined(__ELF__) && defined(_LIBCPP_LINK_PTHREAD_LIB)
19 #pragma comment(lib, "pthread")
20 #endif
21 
22 _LIBCPP_BEGIN_NAMESPACE_STD
23 
24 // ~condition_variable is defined elsewhere.
25 
26 void
27 condition_variable::notify_one() noexcept
28 {
29     __libcpp_condvar_signal(&__cv_);
30 }
31 
32 void
33 condition_variable::notify_all() noexcept
34 {
35     __libcpp_condvar_broadcast(&__cv_);
36 }
37 
38 void
39 condition_variable::wait(unique_lock<mutex>& lk) noexcept
40 {
41     if (!lk.owns_lock())
42         __throw_system_error(EPERM,
43                                   "condition_variable::wait: mutex not locked");
44     int ec = __libcpp_condvar_wait(&__cv_, lk.mutex()->native_handle());
45     if (ec)
46         __throw_system_error(ec, "condition_variable wait failed");
47 }
48 
49 void
50 condition_variable::__do_timed_wait(unique_lock<mutex>& lk,
51      chrono::time_point<chrono::system_clock, chrono::nanoseconds> tp) noexcept
52 {
53     using namespace chrono;
54     if (!lk.owns_lock())
55         __throw_system_error(EPERM,
56                             "condition_variable::timed wait: mutex not locked");
57     nanoseconds d = tp.time_since_epoch();
58     if (d > nanoseconds(0x59682F000000E941))
59         d = nanoseconds(0x59682F000000E941);
60     __libcpp_timespec_t ts;
61     seconds s = duration_cast<seconds>(d);
62     typedef decltype(ts.tv_sec) ts_sec;
63     _LIBCPP_CONSTEXPR ts_sec ts_sec_max = numeric_limits<ts_sec>::max();
64     if (s.count() < ts_sec_max)
65     {
66         ts.tv_sec = static_cast<ts_sec>(s.count());
67         ts.tv_nsec = static_cast<decltype(ts.tv_nsec)>((d - s).count());
68     }
69     else
70     {
71         ts.tv_sec = ts_sec_max;
72         ts.tv_nsec = giga::num - 1;
73     }
74     int ec = __libcpp_condvar_timedwait(&__cv_, lk.mutex()->native_handle(), &ts);
75     if (ec != 0 && ec != ETIMEDOUT)
76         __throw_system_error(ec, "condition_variable timed_wait failed");
77 }
78 
79 void
80 notify_all_at_thread_exit(condition_variable& cond, unique_lock<mutex> lk)
81 {
82     auto& tl_ptr = __thread_local_data();
83     // If this thread was not created using std::thread then it will not have
84     // previously allocated.
85     if (tl_ptr.get() == nullptr) {
86         tl_ptr.set_pointer(new __thread_struct);
87     }
88     __thread_local_data()->notify_all_at_thread_exit(&cond, lk.release());
89 }
90 
91 _LIBCPP_END_NAMESPACE_STD
92 
93 #endif // !_LIBCPP_HAS_NO_THREADS
94