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 #include <system_error>
  16
  17 #if defined(__ELF__) && defined(_LIBCPP_LINK_PTHREAD_LIB)
  18 #  pragma comment(lib, "pthread")
  19 #endif
  20
  21 _LIBCPP_PUSH_MACROS
  22 #include <__undef_macros>
  23
  24 _LIBCPP_BEGIN_NAMESPACE_STD
  25
  26 // ~condition_variable is defined elsewhere.
  27
  28 void
  29 condition_variable::notify_one() noexcept
  30 {
  31     __libcpp_condvar_signal(&__cv_);
  32 }
  33
  34 void
  35 condition_variable::notify_all() noexcept
  36 {
  37     __libcpp_condvar_broadcast(&__cv_);
  38 }
  39
  40 void
  41 condition_variable::wait(unique_lock<mutex>& lk) noexcept
  42 {
  43     if (!lk.owns_lock())
  44         __throw_system_error(EPERM,
  45                                   "condition_variable::wait: mutex not locked");
  46     int ec = __libcpp_condvar_wait(&__cv_, lk.mutex()->native_handle());
  47     if (ec)
  48         __throw_system_error(ec, "condition_variable wait failed");
  49 }
  50
  51 void
  52 condition_variable::__do_timed_wait(unique_lock<mutex>& lk,
  53      chrono::time_point<chrono::system_clock, chrono::nanoseconds> tp) noexcept
  54 {
  55     using namespace chrono;
  56     if (!lk.owns_lock())
  57         __throw_system_error(EPERM,
  58                             "condition_variable::timed wait: mutex not locked");
  59     nanoseconds d = tp.time_since_epoch();
  60     if (d > nanoseconds(0x59682F000000E941))
  61         d = nanoseconds(0x59682F000000E941);
  62     __libcpp_timespec_t ts;
  63     seconds s = duration_cast<seconds>(d);
  64     typedef decltype(ts.tv_sec) ts_sec;
  65     _LIBCPP_CONSTEXPR ts_sec ts_sec_max = numeric_limits<ts_sec>::max();
  66     if (s.count() < ts_sec_max)
  67     {
  68         ts.tv_sec = static_cast<ts_sec>(s.count());
  69         ts.tv_nsec = static_cast<decltype(ts.tv_nsec)>((d - s).count());
  70     }
  71     else
  72     {
  73         ts.tv_sec = ts_sec_max;
  74         ts.tv_nsec = giga::num - 1;
  75     }
  76     int ec = __libcpp_condvar_timedwait(&__cv_, lk.mutex()->native_handle(), &ts);
  77     if (ec != 0 && ec != ETIMEDOUT)
  78         __throw_system_error(ec, "condition_variable timed_wait failed");
  79 }
  80
  81 void
  82 notify_all_at_thread_exit(condition_variable& cond, unique_lock<mutex> lk)
  83 {
  84     auto& tl_ptr = __thread_local_data();
  85     // If this thread was not created using std::thread then it will not have
  86     // previously allocated.
  87     if (tl_ptr.get() == nullptr) {
  88         tl_ptr.set_pointer(new __thread_struct);
  89     }
  90     __thread_local_data()->notify_all_at_thread_exit(&cond, lk.release());
  91 }
  92
  93 _LIBCPP_END_NAMESPACE_STD
  94
  95 _LIBCPP_POP_MACROS
  96
  97 #endif // !_LIBCPP_HAS_NO_THREADS