xref: /freebsd/contrib/llvm-project/libcxx/src/condition_variable.cpp (revision 5ca8e32633c4ffbbcd6762e5888b6a4ba0708c6c)
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 
16 #if defined(__ELF__) && defined(_LIBCPP_LINK_PTHREAD_LIB)
17 #  pragma comment(lib, "pthread")
18 #endif
19 
20 _LIBCPP_PUSH_MACROS
21 #include <__undef_macros>
22 
23 _LIBCPP_BEGIN_NAMESPACE_STD
24 
25 // ~condition_variable is defined elsewhere.
26 
27 void
28 condition_variable::notify_one() noexcept
29 {
30     __libcpp_condvar_signal(&__cv_);
31 }
32 
33 void
34 condition_variable::notify_all() noexcept
35 {
36     __libcpp_condvar_broadcast(&__cv_);
37 }
38 
39 void
40 condition_variable::wait(unique_lock<mutex>& lk) noexcept
41 {
42     if (!lk.owns_lock())
43         __throw_system_error(EPERM,
44                                   "condition_variable::wait: mutex not locked");
45     int ec = __libcpp_condvar_wait(&__cv_, lk.mutex()->native_handle());
46     if (ec)
47         __throw_system_error(ec, "condition_variable wait failed");
48 }
49 
50 void
51 condition_variable::__do_timed_wait(unique_lock<mutex>& lk,
52      chrono::time_point<chrono::system_clock, chrono::nanoseconds> tp) noexcept
53 {
54     using namespace chrono;
55     if (!lk.owns_lock())
56         __throw_system_error(EPERM,
57                             "condition_variable::timed wait: mutex not locked");
58     nanoseconds d = tp.time_since_epoch();
59     if (d > nanoseconds(0x59682F000000E941))
60         d = nanoseconds(0x59682F000000E941);
61     __libcpp_timespec_t ts;
62     seconds s = duration_cast<seconds>(d);
63     typedef decltype(ts.tv_sec) ts_sec;
64     _LIBCPP_CONSTEXPR ts_sec ts_sec_max = numeric_limits<ts_sec>::max();
65     if (s.count() < ts_sec_max)
66     {
67         ts.tv_sec = static_cast<ts_sec>(s.count());
68         ts.tv_nsec = static_cast<decltype(ts.tv_nsec)>((d - s).count());
69     }
70     else
71     {
72         ts.tv_sec = ts_sec_max;
73         ts.tv_nsec = giga::num - 1;
74     }
75     int ec = __libcpp_condvar_timedwait(&__cv_, lk.mutex()->native_handle(), &ts);
76     if (ec != 0 && ec != ETIMEDOUT)
77         __throw_system_error(ec, "condition_variable timed_wait failed");
78 }
79 
80 void
81 notify_all_at_thread_exit(condition_variable& cond, unique_lock<mutex> lk)
82 {
83     auto& tl_ptr = __thread_local_data();
84     // If this thread was not created using std::thread then it will not have
85     // previously allocated.
86     if (tl_ptr.get() == nullptr) {
87         tl_ptr.set_pointer(new __thread_struct);
88     }
89     __thread_local_data()->notify_all_at_thread_exit(&cond, lk.release());
90 }
91 
92 _LIBCPP_END_NAMESPACE_STD
93 
94 _LIBCPP_POP_MACROS
95 
96 #endif // !_LIBCPP_HAS_NO_THREADS
97