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103 lines
2.5 KiB
C++
103 lines
2.5 KiB
C++
/*! \file
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* \brief The locking_ptr is smart pointer with a scoped locking mechanism.
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*
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* The class is a wrapper for a volatile pointer. It enables synchronized access to the
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* internal pointer by locking the passed mutex.
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* locking_ptr is based on Andrei Alexandrescu's LockingPtr. For more information
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* see article "volatile - Multithreaded Programmer's Best Friend" by A. Alexandrescu.
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*
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*
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* Copyright (c) 2005-2007 Philipp Henkel
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*
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* Use, modification, and distribution are subject to the
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* Boost Software License, Version 1.0. (See accompanying file
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* LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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*
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* http://threadpool.sourceforge.net
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*
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*/
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#ifndef THREADPOOL_DETAIL_LOCKING_PTR_HPP_INCLUDED
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#define THREADPOOL_DETAIL_LOCKING_PTR_HPP_INCLUDED
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#include <boost/utility.hpp>
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// Support for old boost::thread
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//**********************************************
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#include <boost/thread/mutex.hpp>
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#ifndef BOOST_THREAD_MUTEX_HPP
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#include <boost/thread/detail/lock.hpp>
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#endif
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//**********************************************
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namespace boost { namespace threadpool { namespace detail
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{
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/*! \brief Smart pointer with a scoped locking mechanism.
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*
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* This class is a wrapper for a volatile pointer. It enables synchronized access to the
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* internal pointer by locking the passed mutex.
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*/
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template <typename T, typename Mutex>
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class locking_ptr
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: private noncopyable
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{
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T* m_obj; //!< The instance pointer.
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Mutex & m_mutex; //!< Mutex is used for scoped locking.
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public:
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/// Constructor.
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locking_ptr(volatile T& obj, const volatile Mutex& mtx)
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: m_obj(const_cast<T*>(&obj))
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, m_mutex(*const_cast<Mutex*>(&mtx))
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{
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// Lock mutex
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#ifndef BOOST_THREAD_MUTEX_HPP
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// Support for old boost::thread
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boost::detail::thread::lock_ops<Mutex>::lock(m_mutex);
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#else
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m_mutex.lock();
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#endif
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}
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/// Destructor.
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~locking_ptr()
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{
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// Unlock mutex
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#ifndef BOOST_THREAD_MUTEX_HPP
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// Support for old boost::thread
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boost::detail::thread::lock_ops<Mutex>::unlock(m_mutex);
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#else
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m_mutex.unlock();
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#endif
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}
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/*! Returns a reference to the stored instance.
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* \return The instance's reference.
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*/
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T& operator*() const
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{
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return *m_obj;
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}
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/*! Returns a pointer to the stored instance.
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* \return The instance's pointer.
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*/
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T* operator->() const
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{
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return m_obj;
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}
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};
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} } } // namespace boost::threadpool::detail
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#endif // THREADPOOL_DETAIL_LOCKING_PTR_HPP_INCLUDED
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