cxx/src/condition_variable.cpp
Howard Hinnant cf115d2cc6 Change sleep_for, sleep_until, and the condition_variable timed wait
functions to protect against duration and time_point overflow.  Since
we're about to wait anyway, we can afford to spend a few more cycles on
this checking.  I purposefully did not treat the timed try_locks with
overflow checking.  This fixes
http://llvm.org/bugs/show_bug.cgi?id=13721 .  I'm unsure if the standard
needs clarification in this area, or if this is simply QOI.  The
<chrono> facilities were never intended to overflow check, but just to
not overflow if durations stayed within +/- 292 years.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@162925 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-30 19:14:33 +00:00

82 lines
2.3 KiB
C++

//===-------------------- condition_variable.cpp --------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "condition_variable"
#include "thread"
#include "system_error"
#include "cassert"
_LIBCPP_BEGIN_NAMESPACE_STD
condition_variable::~condition_variable()
{
pthread_cond_destroy(&__cv_);
}
void
condition_variable::notify_one() _NOEXCEPT
{
pthread_cond_signal(&__cv_);
}
void
condition_variable::notify_all() _NOEXCEPT
{
pthread_cond_broadcast(&__cv_);
}
void
condition_variable::wait(unique_lock<mutex>& lk)
{
if (!lk.owns_lock())
__throw_system_error(EPERM,
"condition_variable::wait: mutex not locked");
int ec = pthread_cond_wait(&__cv_, lk.mutex()->native_handle());
if (ec)
__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)
{
using namespace chrono;
if (!lk.owns_lock())
__throw_system_error(EPERM,
"condition_variable::timed wait: mutex not locked");
nanoseconds d = tp.time_since_epoch();
if (d > nanoseconds(0x59682F000000E941))
d = nanoseconds(0x59682F000000E941);
timespec ts;
seconds s = duration_cast<seconds>(d);
typedef decltype(ts.tv_sec) ts_sec;
_LIBCPP_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 = pthread_cond_timedwait(&__cv_, lk.mutex()->native_handle(), &ts);
if (ec != 0 && ec != ETIMEDOUT)
__throw_system_error(ec, "condition_variable timed_wait failed");
}
void
notify_all_at_thread_exit(condition_variable& cond, unique_lock<mutex> lk)
{
__thread_local_data()->notify_all_at_thread_exit(&cond, lk.release());
}
_LIBCPP_END_NAMESPACE_STD