xref: /freebsd/contrib/llvm-project/libcxx/src/condition_variable.cpp (revision 7ef62cebc2f965b0f640263e179276928885e33d)
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 
17 #if defined(__ELF__) && defined(_LIBCPP_LINK_PTHREAD_LIB)
18 #  pragma comment(lib, "pthread")
19 #endif
20 
21 _LIBCPP_PUSH_MACROS
22 #include <__undef_macros>
23 
24 _LIBCPP_BEGIN_NAMESPACE_STD
25 
26 // ~condition_variable is defined elsewhere.
27 
28 void
29 condition_variable::notify_one() noexcept
30 {
31     __libcpp_condvar_signal(&__cv_);
32 }
33 
34 void
35 condition_variable::notify_all() noexcept
36 {
37     __libcpp_condvar_broadcast(&__cv_);
38 }
39 
40 void
41 condition_variable::wait(unique_lock<mutex>& lk) noexcept
42 {
43     if (!lk.owns_lock())
44         __throw_system_error(EPERM,
45                                   "condition_variable::wait: mutex not locked");
46     int ec = __libcpp_condvar_wait(&__cv_, lk.mutex()->native_handle());
47     if (ec)
48         __throw_system_error(ec, "condition_variable wait failed");
49 }
50 
51 void
52 condition_variable::__do_timed_wait(unique_lock<mutex>& lk,
53      chrono::time_point<chrono::system_clock, chrono::nanoseconds> tp) noexcept
54 {
55     using namespace chrono;
56     if (!lk.owns_lock())
57         __throw_system_error(EPERM,
58                             "condition_variable::timed wait: mutex not locked");
59     nanoseconds d = tp.time_since_epoch();
60     if (d > nanoseconds(0x59682F000000E941))
61         d = nanoseconds(0x59682F000000E941);
62     __libcpp_timespec_t ts;
63     seconds s = duration_cast<seconds>(d);
64     typedef decltype(ts.tv_sec) ts_sec;
65     _LIBCPP_CONSTEXPR ts_sec ts_sec_max = numeric_limits<ts_sec>::max();
66     if (s.count() < ts_sec_max)
67     {
68         ts.tv_sec = static_cast<ts_sec>(s.count());
69         ts.tv_nsec = static_cast<decltype(ts.tv_nsec)>((d - s).count());
70     }
71     else
72     {
73         ts.tv_sec = ts_sec_max;
74         ts.tv_nsec = giga::num - 1;
75     }
76     int ec = __libcpp_condvar_timedwait(&__cv_, lk.mutex()->native_handle(), &ts);
77     if (ec != 0 && ec != ETIMEDOUT)
78         __throw_system_error(ec, "condition_variable timed_wait failed");
79 }
80 
81 void
82 notify_all_at_thread_exit(condition_variable& cond, unique_lock<mutex> lk)
83 {
84     auto& tl_ptr = __thread_local_data();
85     // If this thread was not created using std::thread then it will not have
86     // previously allocated.
87     if (tl_ptr.get() == nullptr) {
88         tl_ptr.set_pointer(new __thread_struct);
89     }
90     __thread_local_data()->notify_all_at_thread_exit(&cond, lk.release());
91 }
92 
93 _LIBCPP_END_NAMESPACE_STD
94 
95 _LIBCPP_POP_MACROS
96 
97 #endif // !_LIBCPP_HAS_NO_THREADS
98