libcxx/src/condition_variable.cpp

//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#include <condition_variable>
#include <limits>
#include <ratio>
#include <thread>
#include <__chrono/duration.h>
#include <__chrono/system_clock.h>
#include <__chrono/time_point.h>
#include <__system_error/throw_system_error.h>

#if defined(__ELF__) && defined(_LIBCPP_LINK_PTHREAD_LIB)
#  pragma comment(lib, "pthread")
#endif

_LIBCPP_PUSH_MACROS
#include <__undef_macros>

_LIBCPP_BEGIN_NAMESPACE_STD

// ~condition_variable is defined elsewhere.

void condition_variable::notify_one() noexcept { __libcpp_condvar_signal(&__cv_); }

void condition_variable::notify_all() noexcept { __libcpp_condvar_broadcast(&__cv_); }

void condition_variable::wait(unique_lock<mutex>& lk) noexcept {
  if (!lk.owns_lock())
    std::__throw_system_error(EPERM, "condition_variable::wait: mutex not locked");
  int ec = __libcpp_condvar_wait(&__cv_, lk.mutex()->native_handle());
  if (ec)
    std::__throw_system_error(ec, "condition_variable wait failed");
}

void condition_variable::__do_timed_wait(unique_lock<mutex>& lk,
                                         chrono::time_point<chrono::system_clock, chrono::nanoseconds> tp) noexcept {
  using namespace chrono;
  if (!lk.owns_lock())
    std::__throw_system_error(EPERM, "condition_variable::timed wait: mutex not locked");
  nanoseconds d = tp.time_since_epoch();
  if (d > nanoseconds(0x59682F000000E941))
    d = nanoseconds(0x59682F000000E941);
  __libcpp_timespec_t ts;
  seconds s = duration_cast<seconds>(d);
  typedef decltype(ts.tv_sec) ts_sec;
  constexpr ts_sec ts_sec_max = numeric_limits<ts_sec>::max();
  if (s.count() < ts_sec_max) {
    ts.tv_sec  = static_cast<ts_sec>(s.count());
    ts.tv_nsec = static_cast<decltype(ts.tv_nsec)>((d - s).count());
  } else {
    ts.tv_sec  = ts_sec_max;
    ts.tv_nsec = giga::num - 1;
  }
  int ec = __libcpp_condvar_timedwait(&__cv_, lk.mutex()->native_handle(), &ts);
  if (ec != 0 && ec != ETIMEDOUT)
    std::__throw_system_error(ec, "condition_variable timed_wait failed");
}

void notify_all_at_thread_exit(condition_variable& cond, unique_lock<mutex> lk) {
  auto& tl_ptr = __thread_local_data();
  // If this thread was not created using std::thread then it will not have
  // previously allocated.
  if (tl_ptr.get() == nullptr) {
    tl_ptr.set_pointer(new __thread_struct);
  }
  __thread_local_data()->notify_all_at_thread_exit(&cond, lk.release());
}

_LIBCPP_END_NAMESPACE_STD

_LIBCPP_POP_MACROS