mutex.h

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/***************************************************************************
 * include/stxxl/bits/common/mutex.h
 *
 * Part of the STXXL. See http://stxxl.sourceforge.net
 *
 * Copyright (C) 2002 Roman Dementiev <[email protected]>
 * Copyright (C) 2008 Andreas Beckmann <[email protected]>
 * Copyright (C) 2013 Timo Bingmann <[email protected]>
 *
 * 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)
 **************************************************************************/

#ifndef STXXL_COMMON_MUTEX_HEADER
#define STXXL_COMMON_MUTEX_HEADER

#include <stxxl/bits/config.h>
#include <stxxl/bits/namespace.h>

#if STXXL_STD_THREADS
 #include <mutex>
#elif STXXL_BOOST_THREADS
 #include <boost/thread/mutex.hpp>
#elif STXXL_POSIX_THREADS
 #include <pthread.h>

 #include <stxxl/bits/noncopyable.h>
 #include <stxxl/bits/common/error_handling.h>
#else
 #error "Thread implementation not detected."
#endif


STXXL_BEGIN_NAMESPACE

#if STXXL_STD_THREADS

typedef std::mutex mutex;

#elif STXXL_BOOST_THREADS

typedef boost::mutex mutex;

#elif STXXL_POSIX_THREADS

class mutex : private noncopyable
{
 //! mutex handle
 pthread_mutex_t m_mutex;

public:
 //! construct unlocked mutex
 mutex()
 {
 STXXL_CHECK_PTHREAD_CALL(pthread_mutex_init(&m_mutex, NULL));
 }
 //! destroy mutex handle
 ~mutex()
 {
 // try simple delete first
 int res = pthread_mutex_destroy(&m_mutex);
 if (res == 0) return;

 // try to lock and unlock mutex
 res = pthread_mutex_trylock(&m_mutex);

 if (res == 0 || res == EBUSY) {
 STXXL_CHECK_PTHREAD_CALL(pthread_mutex_unlock(&m_mutex));
 } else {
 STXXL_THROW_ERRNO2(resource_error, "pthread_mutex_trylock() failed", res);
 }

 STXXL_CHECK_PTHREAD_CALL(pthread_mutex_destroy(&m_mutex));
 }
 //! lock mutex, may block
 void lock()
 {
 STXXL_CHECK_PTHREAD_CALL(pthread_mutex_lock(&m_mutex));
 }
 //! unlock mutex
 void unlock()
 {
 STXXL_CHECK_PTHREAD_CALL(pthread_mutex_unlock(&m_mutex));
 }
 //! return platform specific handle
 pthread_mutex_t & native_handle()
 {
 return m_mutex;
 }
};

#endif

#if STXXL_STD_THREADS

typedef std::unique_lock<std::mutex> scoped_mutex_lock;

#elif STXXL_BOOST_THREADS

typedef boost::mutex::scoped_lock scoped_mutex_lock;

#else

//! Aquire a lock that's valid until the end of scope.
class scoped_mutex_lock
{
 //! mutex reference
 mutex& m_mutex;

 //! marker if already unlocked by this thread (needs no synchronization)
 bool is_locked;

public:
 //! lock mutex
 scoped_mutex_lock(mutex& m)
 : m_mutex(m), is_locked(true)
 {
 m_mutex.lock();
 }
 //! unlock mutex hold when object goes out of scope.
 ~scoped_mutex_lock()
 {
 unlock();
 }
 //! unlock mutex hold prematurely
 void unlock()
 {
 if (is_locked) {
 is_locked = false;
 m_mutex.unlock();
 }
 }
 //! return platform specific handle
 pthread_mutex_t & native_handle()
 {
 return m_mutex.native_handle();
 }
};

#endif

STXXL_END_NAMESPACE

#endif // !STXXL_COMMON_MUTEX_HEADER