libcxx/src/condition_variable.cpp

   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
  24 condition_variable::notify_one() noexcept
  25 {
  26     __libcpp_condvar_signal(&__cv_);
  27 }
  28
  29 void
  30 condition_variable::notify_all() noexcept
  31 {
  32     __libcpp_condvar_broadcast(&__cv_);
  33 }
  34
  35 void
  36 condition_variable::wait(unique_lock<mutex>& lk) noexcept
  37 {
  38     if (!lk.owns_lock())
  39         __throw_system_error(EPERM,
  40                                   "condition_variable::wait: mutex not locked");
  41     int ec = __libcpp_condvar_wait(&__cv_, lk.mutex()->native_handle());
  42     if (ec)
  43         __throw_system_error(ec, "condition_variable wait failed");
  44 }
  45
  46 void
  47 condition_variable::__do_timed_wait(unique_lock<mutex>& lk,
  48      chrono::time_point<chrono::system_clock, chrono::nanoseconds> tp) noexcept
  49 {
  50     using namespace chrono;
  51     if (!lk.owns_lock())
  52         __throw_system_error(EPERM,
  53                             "condition_variable::timed wait: mutex not locked");
  54     nanoseconds d = tp.time_since_epoch();
  55     if (d > nanoseconds(0x59682F000000E941))
  56         d = nanoseconds(0x59682F000000E941);
  57     __libcpp_timespec_t ts;
  58     seconds s = duration_cast<seconds>(d);
  59     typedef decltype(ts.tv_sec) ts_sec;
  60     constexpr ts_sec ts_sec_max = numeric_limits<ts_sec>::max();
  61     if (s.count() < ts_sec_max)
  62     {
  63         ts.tv_sec = static_cast<ts_sec>(s.count());
  64         ts.tv_nsec = static_cast<decltype(ts.tv_nsec)>((d - s).count());
  65     }
  66     else
  67     {
  68         ts.tv_sec = ts_sec_max;
  69         ts.tv_nsec = giga::num - 1;
  70     }
  71     int ec = __libcpp_condvar_timedwait(&__cv_, lk.mutex()->native_handle(), &ts);
  72     if (ec != 0 && ec != ETIMEDOUT)
  73         __throw_system_error(ec, "condition_variable timed_wait failed");
  74 }
  75
  76 void
  77 notify_all_at_thread_exit(condition_variable& cond, unique_lock<mutex> lk)
  78 {
  79     auto& tl_ptr = __thread_local_data();
  80     // If this thread was not created using std::thread then it will not have
  81     // previously allocated.
  82     if (tl_ptr.get() == nullptr) {
  83         tl_ptr.set_pointer(new __thread_struct);
  84     }
  85     __thread_local_data()->notify_all_at_thread_exit(&cond, lk.release());
  86 }
  87
  88 _LIBCPP_END_NAMESPACE_STD
  89
  90 _LIBCPP_POP_MACROS