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 <__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     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