Chris@16: /*
Chris@101:  *          Copyright Andrey Semashev 2007 - 2015.
Chris@16:  * Distributed under the Boost Software License, Version 1.0.
Chris@16:  *    (See accompanying file LICENSE_1_0.txt or copy at
Chris@16:  *          http://www.boost.org/LICENSE_1_0.txt)
Chris@16:  */
Chris@16: /*!
Chris@16:  * \file   locking_ptr.hpp
Chris@16:  * \author Andrey Semashev
Chris@16:  * \date   15.07.2009
Chris@16:  *
Chris@16:  * This header is the Boost.Log library implementation, see the library documentation
Chris@16:  * at http://www.boost.org/doc/libs/release/libs/log/doc/html/index.html.
Chris@16:  */
Chris@16: 
Chris@16: #ifndef BOOST_LOG_DETAIL_LOCKING_PTR_HPP_INCLUDED_
Chris@16: #define BOOST_LOG_DETAIL_LOCKING_PTR_HPP_INCLUDED_
Chris@16: 
Chris@101: #include <cstddef>
Chris@101: #include <boost/move/core.hpp>
Chris@16: #include <boost/smart_ptr/shared_ptr.hpp>
Chris@101: #include <boost/thread/lock_options.hpp>
Chris@16: #include <boost/log/detail/config.hpp>
Chris@16: #include <boost/utility/explicit_operator_bool.hpp>
Chris@16: #include <boost/log/detail/header.hpp>
Chris@16: 
Chris@16: #ifdef BOOST_HAS_PRAGMA_ONCE
Chris@16: #pragma once
Chris@16: #endif
Chris@16: 
Chris@16: namespace boost {
Chris@16: 
Chris@16: BOOST_LOG_OPEN_NAMESPACE
Chris@16: 
Chris@16: namespace aux {
Chris@16: 
Chris@16: //! A pointer type that locks the backend until it's destroyed
Chris@101: template< typename T, typename LockableT >
Chris@16: class locking_ptr
Chris@16: {
Chris@101:     typedef locking_ptr this_type;
Chris@101:     BOOST_COPYABLE_AND_MOVABLE_ALT(this_type)
Chris@101: 
Chris@16: public:
Chris@16:     //! Pointed type
Chris@16:     typedef T element_type;
Chris@16: 
Chris@16: private:
Chris@101:     //! Lockable type
Chris@101:     typedef LockableT lockable_type;
Chris@101: 
Chris@101: private:
Chris@16:     //! The pointer to the backend
Chris@16:     shared_ptr< element_type > m_pElement;
Chris@16:     //! Reference to the shared lock control object
Chris@101:     lockable_type* m_pLock;
Chris@16: 
Chris@16: public:
Chris@101:     //! Default constructor
Chris@101:     locking_ptr() BOOST_NOEXCEPT : m_pLock(NULL)
Chris@16:     {
Chris@16:     }
Chris@16:     //! Constructor
Chris@101:     locking_ptr(shared_ptr< element_type > const& p, lockable_type& l) : m_pElement(p), m_pLock(&l)
Chris@16:     {
Chris@101:         m_pLock->lock();
Chris@101:     }
Chris@101:     //! Constructor
Chris@101:     locking_ptr(shared_ptr< element_type > const& p, lockable_type& l, try_to_lock_t const&) : m_pElement(p), m_pLock(&l)
Chris@101:     {
Chris@101:         if (!m_pLock->try_lock())
Chris@16:         {
Chris@16:             m_pElement.reset();
Chris@16:             m_pLock = NULL;
Chris@16:         }
Chris@16:     }
Chris@16:     //! Copy constructor
Chris@16:     locking_ptr(locking_ptr const& that) : m_pElement(that.m_pElement), m_pLock(that.m_pLock)
Chris@16:     {
Chris@16:         if (m_pLock)
Chris@101:             m_pLock->lock();
Chris@16:     }
Chris@101:     //! Move constructor
Chris@101:     locking_ptr(BOOST_RV_REF(this_type) that) BOOST_NOEXCEPT : m_pLock(that.m_pLock)
Chris@101:     {
Chris@101:         m_pElement.swap(that.m_pElement);
Chris@101:         that.m_pLock = NULL;
Chris@101:     }
Chris@101: 
Chris@16:     //! Destructor
Chris@16:     ~locking_ptr()
Chris@16:     {
Chris@101:         if (m_pLock)
Chris@16:             m_pLock->unlock();
Chris@16:     }
Chris@16: 
Chris@16:     //! Assignment
Chris@101:     locking_ptr& operator= (locking_ptr that) BOOST_NOEXCEPT
Chris@16:     {
Chris@16:         this->swap(that);
Chris@16:         return *this;
Chris@16:     }
Chris@16: 
Chris@16:     //! Indirection
Chris@101:     element_type* operator-> () const BOOST_NOEXCEPT { return m_pElement.get(); }
Chris@16:     //! Dereferencing
Chris@101:     element_type& operator* () const BOOST_NOEXCEPT { return *m_pElement; }
Chris@16: 
Chris@16:     //! Accessor to the raw pointer
Chris@101:     element_type* get() const BOOST_NOEXCEPT { return m_pElement.get(); }
Chris@16: 
Chris@16:     //! Checks for null pointer
Chris@101:     BOOST_EXPLICIT_OPERATOR_BOOL_NOEXCEPT()
Chris@16:     //! Checks for null pointer
Chris@101:     bool operator! () const BOOST_NOEXCEPT { return !m_pElement; }
Chris@16: 
Chris@16:     //! Swaps two pointers
Chris@101:     void swap(locking_ptr& that) BOOST_NOEXCEPT
Chris@16:     {
Chris@16:         m_pElement.swap(that.m_pElement);
Chris@101:         lockable_type* p = m_pLock;
Chris@16:         m_pLock = that.m_pLock;
Chris@16:         that.m_pLock = p;
Chris@16:     }
Chris@16: };
Chris@16: 
Chris@16: //! Free raw pointer getter to assist generic programming
Chris@101: template< typename T, typename LockableT >
Chris@101: inline T* get_pointer(locking_ptr< T, LockableT > const& p) BOOST_NOEXCEPT
Chris@16: {
Chris@16:     return p.get();
Chris@16: }
Chris@16: //! Free swap operation
Chris@101: template< typename T, typename LockableT >
Chris@101: inline void swap(locking_ptr< T, LockableT >& left, locking_ptr< T, LockableT >& right) BOOST_NOEXCEPT
Chris@16: {
Chris@16:     left.swap(right);
Chris@16: }
Chris@16: 
Chris@16: } // namespace aux
Chris@16: 
Chris@16: BOOST_LOG_CLOSE_NAMESPACE // namespace log
Chris@16: 
Chris@16: } // namespace boost
Chris@16: 
Chris@16: #include <boost/log/detail/footer.hpp>
Chris@16: 
Chris@16: #endif // BOOST_LOG_DETAIL_LOCKING_PTR_HPP_INCLUDED_