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