xref: /freebsd/contrib/llvm-project/libcxx/src/condition_variable.cpp (revision 770cf0a5f02dc8983a89c6568d741fbc25baa999)
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 <limits>
11 #include <ratio>
12 #include <thread>
13 #include <__chrono/duration.h>
14 #include <__chrono/system_clock.h>
15 #include <__chrono/time_point.h>
16 #include <__system_error/throw_system_error.h>
17 
18 #if defined(__ELF__) && defined(_LIBCPP_LINK_PTHREAD_LIB)
19 #  pragma comment(lib, "pthread")
20 #endif
21 
22 _LIBCPP_PUSH_MACROS
23 #include <__undef_macros>
24 
25 _LIBCPP_BEGIN_NAMESPACE_STD
26 
27 // ~condition_variable is defined elsewhere.
28 
29 void condition_variable::notify_one() noexcept { __libcpp_condvar_signal(&__cv_); }
30 
31 void condition_variable::notify_all() noexcept { __libcpp_condvar_broadcast(&__cv_); }
32 
33 void condition_variable::wait(unique_lock<mutex>& lk) noexcept {
34   if (!lk.owns_lock())
35     std::__throw_system_error(EPERM, "condition_variable::wait: mutex not locked");
36   int ec = __libcpp_condvar_wait(&__cv_, lk.mutex()->native_handle());
37   if (ec)
38     std::__throw_system_error(ec, "condition_variable wait failed");
39 }
40 
41 void condition_variable::__do_timed_wait(unique_lock<mutex>& lk,
42                                          chrono::time_point<chrono::system_clock, chrono::nanoseconds> tp) noexcept {
43   using namespace chrono;
44   if (!lk.owns_lock())
45     std::__throw_system_error(EPERM, "condition_variable::timed wait: mutex not locked");
46   nanoseconds d = tp.time_since_epoch();
47   if (d > nanoseconds(0x59682F000000E941))
48     d = nanoseconds(0x59682F000000E941);
49   __libcpp_timespec_t ts;
50   seconds s = duration_cast<seconds>(d);
51   typedef decltype(ts.tv_sec) ts_sec;
52   constexpr ts_sec ts_sec_max = numeric_limits<ts_sec>::max();
53   if (s.count() < ts_sec_max) {
54     ts.tv_sec  = static_cast<ts_sec>(s.count());
55     ts.tv_nsec = static_cast<decltype(ts.tv_nsec)>((d - s).count());
56   } else {
57     ts.tv_sec  = ts_sec_max;
58     ts.tv_nsec = giga::num - 1;
59   }
60   int ec = __libcpp_condvar_timedwait(&__cv_, lk.mutex()->native_handle(), &ts);
61   if (ec != 0 && ec != ETIMEDOUT)
62     std::__throw_system_error(ec, "condition_variable timed_wait failed");
63 }
64 
65 void notify_all_at_thread_exit(condition_variable& cond, unique_lock<mutex> lk) {
66   auto& tl_ptr = __thread_local_data();
67   // If this thread was not created using std::thread then it will not have
68   // previously allocated.
69   if (tl_ptr.get() == nullptr) {
70     tl_ptr.set_pointer(new __thread_struct);
71   }
72   __thread_local_data()->notify_all_at_thread_exit(&cond, lk.release());
73 }
74 
75 _LIBCPP_END_NAMESPACE_STD
76 
77 _LIBCPP_POP_MACROS
78