mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-10-25 18:00:51 +00:00
103 lines
2.5 KiB
C++
103 lines
2.5 KiB
C++
/*! \file
|
|
* \brief The locking_ptr is smart pointer with a scoped locking mechanism.
|
|
*
|
|
* The class is a wrapper for a volatile pointer. It enables synchronized access to the
|
|
* internal pointer by locking the passed mutex.
|
|
* locking_ptr is based on Andrei Alexandrescu's LockingPtr. For more information
|
|
* see article "volatile - Multithreaded Programmer's Best Friend" by A. Alexandrescu.
|
|
*
|
|
*
|
|
* Copyright (c) 2005-2007 Philipp Henkel
|
|
*
|
|
* Use, modification, and distribution are subject to 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)
|
|
*
|
|
* http://threadpool.sourceforge.net
|
|
*
|
|
*/
|
|
|
|
|
|
#ifndef THREADPOOL_DETAIL_LOCKING_PTR_HPP_INCLUDED
|
|
#define THREADPOOL_DETAIL_LOCKING_PTR_HPP_INCLUDED
|
|
|
|
#include <boost/utility.hpp>
|
|
|
|
// Support for old boost::thread
|
|
//**********************************************
|
|
#include <boost/thread/mutex.hpp>
|
|
#ifndef BOOST_THREAD_MUTEX_HPP
|
|
#include <boost/thread/detail/lock.hpp>
|
|
#endif
|
|
//**********************************************
|
|
|
|
namespace boost { namespace threadpool { namespace detail
|
|
{
|
|
|
|
/*! \brief Smart pointer with a scoped locking mechanism.
|
|
*
|
|
* This class is a wrapper for a volatile pointer. It enables synchronized access to the
|
|
* internal pointer by locking the passed mutex.
|
|
*/
|
|
template <typename T, typename Mutex>
|
|
class locking_ptr
|
|
: private noncopyable
|
|
{
|
|
T* m_obj; //!< The instance pointer.
|
|
Mutex & m_mutex; //!< Mutex is used for scoped locking.
|
|
|
|
public:
|
|
/// Constructor.
|
|
locking_ptr(volatile T& obj, const volatile Mutex& mtx)
|
|
: m_obj(const_cast<T*>(&obj))
|
|
, m_mutex(*const_cast<Mutex*>(&mtx))
|
|
{
|
|
// Lock mutex
|
|
|
|
#ifndef BOOST_THREAD_MUTEX_HPP
|
|
// Support for old boost::thread
|
|
boost::detail::thread::lock_ops<Mutex>::lock(m_mutex);
|
|
#else
|
|
m_mutex.lock();
|
|
#endif
|
|
}
|
|
|
|
|
|
/// Destructor.
|
|
~locking_ptr()
|
|
{
|
|
// Unlock mutex
|
|
#ifndef BOOST_THREAD_MUTEX_HPP
|
|
// Support for old boost::thread
|
|
boost::detail::thread::lock_ops<Mutex>::unlock(m_mutex);
|
|
#else
|
|
m_mutex.unlock();
|
|
#endif
|
|
}
|
|
|
|
|
|
/*! Returns a reference to the stored instance.
|
|
* \return The instance's reference.
|
|
*/
|
|
T& operator*() const
|
|
{
|
|
return *m_obj;
|
|
}
|
|
|
|
|
|
/*! Returns a pointer to the stored instance.
|
|
* \return The instance's pointer.
|
|
*/
|
|
T* operator->() const
|
|
{
|
|
return m_obj;
|
|
}
|
|
};
|
|
|
|
|
|
} } } // namespace boost::threadpool::detail
|
|
|
|
|
|
#endif // THREADPOOL_DETAIL_LOCKING_PTR_HPP_INCLUDED
|
|
|