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event.cpp
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277 lines (230 loc) · 6.86 KB
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/*
* Copyright Andrey Semashev 2007 - 2015.
* Distributed under the Boost Software License, Version 1.0.
* (See accompanying file LICENSE_1_0.txt or copy at
* http://www.boost.org/LICENSE_1_0.txt)
*/
/*!
* \file event.cpp
* \author Andrey Semashev
* \date 24.07.2011
*
* \brief This header is the Boost.Log library implementation, see the library documentation
* at http://www.boost.org/doc/libs/release/libs/log/doc/html/index.html.
*/
#include <boost/log/detail/config.hpp>
#ifndef BOOST_LOG_NO_THREADS
#include <boost/assert.hpp>
#include <boost/cstdint.hpp>
#include <boost/throw_exception.hpp>
#include <boost/log/detail/event.hpp>
#include <boost/log/exceptions.hpp>
#if defined(BOOST_LOG_EVENT_USE_FUTEX)
#include <stddef.h>
#include <errno.h>
#include <sys/syscall.h>
#include <linux/futex.h>
#include <boost/memory_order.hpp>
// Some Android NDKs (Google NDK and older Crystax.NET NDK versions) don't define SYS_futex
#if defined(SYS_futex)
#define BOOST_LOG_SYS_FUTEX SYS_futex
#else
#define BOOST_LOG_SYS_FUTEX __NR_futex
#endif
#if defined(FUTEX_WAIT_PRIVATE)
#define BOOST_LOG_FUTEX_WAIT FUTEX_WAIT_PRIVATE
#else
#define BOOST_LOG_FUTEX_WAIT FUTEX_WAIT
#endif
#if defined(FUTEX_WAKE_PRIVATE)
#define BOOST_LOG_FUTEX_WAKE FUTEX_WAKE_PRIVATE
#else
#define BOOST_LOG_FUTEX_WAKE FUTEX_WAKE
#endif
#elif defined(BOOST_LOG_EVENT_USE_POSIX_SEMAPHORE)
#include <errno.h>
#include <semaphore.h>
#include <boost/memory_order.hpp>
#include <boost/atomic/fences.hpp>
#elif defined(BOOST_LOG_EVENT_USE_WINAPI)
#include <windows.h>
#include <boost/detail/interlocked.hpp>
#else
#include <boost/thread/locks.hpp>
#endif
#include <boost/log/detail/header.hpp>
namespace boost {
BOOST_LOG_OPEN_NAMESPACE
namespace aux {
#if defined(BOOST_LOG_EVENT_USE_FUTEX)
//! Default constructor
BOOST_LOG_API futex_based_event::futex_based_event() : m_state(0)
{
}
//! Destructor
BOOST_LOG_API futex_based_event::~futex_based_event()
{
}
//! Waits for the object to become signalled
BOOST_LOG_API void futex_based_event::wait()
{
if (m_state.exchange(0, boost::memory_order_acq_rel) == 0)
{
while (true)
{
if (::syscall(BOOST_LOG_SYS_FUTEX, &m_state.storage(), BOOST_LOG_FUTEX_WAIT, 0, NULL, NULL, 0) == 0)
{
// Another thread has set the event while sleeping
break;
}
const int err = errno;
if (err == EWOULDBLOCK)
{
// Another thread has set the event before sleeping
break;
}
else if (BOOST_UNLIKELY(err != EINTR))
{
BOOST_LOG_THROW_DESCR_PARAMS(system_error, "Failed to block on the futex", (err));
}
}
m_state.store(0, boost::memory_order_relaxed);
}
}
//! Sets the object to a signalled state
BOOST_LOG_API void futex_based_event::set_signalled()
{
if (m_state.exchange(1, boost::memory_order_release) == 0)
{
if (BOOST_UNLIKELY(::syscall(BOOST_LOG_SYS_FUTEX, &m_state.storage(), BOOST_LOG_FUTEX_WAKE, 1, NULL, NULL, 0) < 0))
{
const int err = errno;
BOOST_LOG_THROW_DESCR_PARAMS(system_error, "Failed to wake threads blocked on the futex", (err));
}
}
}
#elif defined(BOOST_LOG_EVENT_USE_POSIX_SEMAPHORE)
//! Default constructor
BOOST_LOG_API sem_based_event::sem_based_event() : m_state()
{
if (BOOST_UNLIKELY(sem_init(&m_semaphore, 0, 0) != 0))
{
const int err = errno;
BOOST_LOG_THROW_DESCR_PARAMS(system_error, "Failed to initialize semaphore", (err));
}
}
//! Destructor
BOOST_LOG_API sem_based_event::~sem_based_event()
{
BOOST_VERIFY(sem_destroy(&m_semaphore) == 0);
}
//! Waits for the object to become signalled
BOOST_LOG_API void sem_based_event::wait()
{
boost::atomic_thread_fence(boost::memory_order_acq_rel);
while (true)
{
if (sem_wait(&m_semaphore) != 0)
{
const int err = errno;
if (BOOST_UNLIKELY(err != EINTR))
{
BOOST_LOG_THROW_DESCR_PARAMS(system_error, "Failed to block on the semaphore", (err));
}
}
else
break;
}
m_state.clear(boost::memory_order_relaxed);
}
//! Sets the object to a signalled state
BOOST_LOG_API void sem_based_event::set_signalled()
{
if (!m_state.test_and_set(boost::memory_order_release))
{
if (BOOST_UNLIKELY(sem_post(&m_semaphore) != 0))
{
const int err = errno;
BOOST_LOG_THROW_DESCR_PARAMS(system_error, "Failed to wake the blocked thread", (err));
}
}
}
#elif defined(BOOST_LOG_EVENT_USE_WINAPI)
//! Default constructor
BOOST_LOG_API winapi_based_event::winapi_based_event() :
m_state(0),
m_event(CreateEventA(NULL, false, false, NULL))
{
if (BOOST_UNLIKELY(!m_event))
{
const DWORD err = GetLastError();
BOOST_LOG_THROW_DESCR_PARAMS(system_error, "Failed to create Windows event", (err));
}
}
//! Destructor
BOOST_LOG_API winapi_based_event::~winapi_based_event()
{
BOOST_VERIFY(CloseHandle(m_event) != 0);
}
//! Waits for the object to become signalled
BOOST_LOG_API void winapi_based_event::wait()
{
// On Windows we assume that memory view is always actual (Intel x86 and x86_64 arch)
if (const_cast< volatile boost::uint32_t& >(m_state) == 0)
{
if (BOOST_UNLIKELY(WaitForSingleObject(m_event, INFINITE) != 0))
{
const DWORD err = GetLastError();
BOOST_LOG_THROW_DESCR_PARAMS(system_error, "Failed to block on Windows event", (err));
}
}
const_cast< volatile boost::uint32_t& >(m_state) = 0;
}
//! Sets the object to a signalled state
BOOST_LOG_API void winapi_based_event::set_signalled()
{
if (BOOST_INTERLOCKED_COMPARE_EXCHANGE(reinterpret_cast< long* >(&m_state), 1, 0) == 0)
{
if (BOOST_UNLIKELY(SetEvent(m_event) == 0))
{
const DWORD err = GetLastError();
const_cast< volatile boost::uint32_t& >(m_state) = 0;
BOOST_LOG_THROW_DESCR_PARAMS(system_error, "Failed to wake the blocked thread", (err));
}
}
}
#else
//! Default constructor
BOOST_LOG_API generic_event::generic_event() : m_state(false)
{
}
//! Destructor
BOOST_LOG_API generic_event::~generic_event()
{
}
//! Waits for the object to become signalled
BOOST_LOG_API void generic_event::wait()
{
boost::unique_lock< boost::mutex > lock(m_mutex);
while (!m_state)
{
m_cond.wait(lock);
}
m_state = false;
}
//! Sets the object to a signalled state
BOOST_LOG_API void generic_event::set_signalled()
{
boost::lock_guard< boost::mutex > lock(m_mutex);
if (!m_state)
{
m_state = true;
m_cond.notify_one();
}
}
#endif
} // namespace aux
BOOST_LOG_CLOSE_NAMESPACE // namespace log
} // namespace boost
#include <boost/log/detail/footer.hpp>
#endif // BOOST_LOG_NO_THREADS