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   locks.hpp
Chris@16:  * \author Andrey Semashev
Chris@16:  * \date   30.05.2010
Chris@16:  *
Chris@16:  * \brief  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_LOCKS_HPP_INCLUDED_
Chris@16: #define BOOST_LOG_DETAIL_LOCKS_HPP_INCLUDED_
Chris@16: 
Chris@16: #include <boost/log/detail/config.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: #ifndef BOOST_LOG_NO_THREADS
Chris@16: 
Chris@16: // Forward declaration of Boost.Thread locks. Specified here to avoid including Boost.Thread,
Chris@16: // which would bring in many dependent headers, including a great deal of Boost.DateTime.
Chris@16: template< typename >
Chris@16: class lock_guard;
Chris@16: template< typename >
Chris@16: class shared_lock;
Chris@16: template< typename >
Chris@16: class upgrade_lock;
Chris@16: template< typename >
Chris@16: class unique_lock;
Chris@16: 
Chris@16: template< typename >
Chris@16: struct is_mutex_type;
Chris@16: 
Chris@16: #endif // BOOST_LOG_NO_THREADS
Chris@16: 
Chris@16: BOOST_LOG_OPEN_NAMESPACE
Chris@16: 
Chris@16: //! An auxiliary pseudo-lock to express no locking requirements in logger features
Chris@16: template< typename MutexT >
Chris@16: class no_lock
Chris@16: {
Chris@16: public:
Chris@16:     /*!
Chris@16:      * Constructs the pseudo-lock. The mutex is not affected during the construction.
Chris@16:      */
Chris@16:     explicit no_lock(MutexT&) {}
Chris@16: 
Chris@16: private:
Chris@16:     no_lock(no_lock const&);
Chris@16:     no_lock& operator= (no_lock const&);
Chris@16: };
Chris@16: 
Chris@16: namespace aux {
Chris@16: 
Chris@16: #ifndef BOOST_LOG_NO_THREADS
Chris@16: 
Chris@16: //! A trait to detect if the mutex supports exclusive locking
Chris@16: template< typename MutexT >
Chris@16: struct is_exclusively_lockable
Chris@16: {
Chris@16:     typedef char true_type;
Chris@16:     struct false_type { char t[2]; };
Chris@16: 
Chris@16:     template< typename T >
Chris@16:     static true_type check_lockable(T*, void (T::*)() = &T::lock, void (T::*)() = &T::unlock);
Chris@16:     static false_type check_lockable(void*);
Chris@16: 
Chris@16:     enum value_t { value = sizeof(check_lockable((MutexT*)NULL)) == sizeof(true_type) };
Chris@16: };
Chris@16: 
Chris@16: //! A trait to detect if the mutex supports shared locking
Chris@16: template< typename MutexT >
Chris@16: struct is_shared_lockable
Chris@16: {
Chris@16:     typedef char true_type;
Chris@16:     struct false_type { char t[2]; };
Chris@16: 
Chris@16:     template< typename T >
Chris@16:     static true_type check_shared_lockable(T*, void (T::*)() = &T::lock_shared, void (T::*)() = &T::unlock_shared);
Chris@16:     static false_type check_shared_lockable(void*);
Chris@16: 
Chris@16:     enum value_t { value = sizeof(check_shared_lockable((MutexT*)NULL)) == sizeof(true_type) };
Chris@16: };
Chris@16: 
Chris@16: //! An analogue to the minimalistic \c lock_guard template. Defined here to avoid including Boost.Thread.
Chris@16: template< typename MutexT >
Chris@16: struct exclusive_lock_guard
Chris@16: {
Chris@16:     explicit exclusive_lock_guard(MutexT& m) : m_Mutex(m)
Chris@16:     {
Chris@16:         m.lock();
Chris@16:     }
Chris@16:     ~exclusive_lock_guard()
Chris@16:     {
Chris@16:         m_Mutex.unlock();
Chris@16:     }
Chris@16: 
Chris@16: private:
Chris@16:     exclusive_lock_guard(exclusive_lock_guard const&);
Chris@16:     exclusive_lock_guard& operator= (exclusive_lock_guard const&);
Chris@16: 
Chris@16: private:
Chris@16:     MutexT& m_Mutex;
Chris@16: };
Chris@16: 
Chris@16: //! An analogue to the minimalistic \c lock_guard template that locks \c shared_mutex with shared ownership.
Chris@16: template< typename MutexT >
Chris@16: struct shared_lock_guard
Chris@16: {
Chris@16:     explicit shared_lock_guard(MutexT& m) : m_Mutex(m)
Chris@16:     {
Chris@16:         m.lock_shared();
Chris@16:     }
Chris@16:     ~shared_lock_guard()
Chris@16:     {
Chris@16:         m_Mutex.unlock_shared();
Chris@16:     }
Chris@16: 
Chris@16: private:
Chris@16:     shared_lock_guard(shared_lock_guard const&);
Chris@16:     shared_lock_guard& operator= (shared_lock_guard const&);
Chris@16: 
Chris@16: private:
Chris@16:     MutexT& m_Mutex;
Chris@16: };
Chris@16: 
Chris@16: //! A deadlock-safe lock type that exclusively locks two mutexes
Chris@16: template< typename MutexT1, typename MutexT2 >
Chris@16: class multiple_unique_lock2
Chris@16: {
Chris@16: public:
Chris@16:     multiple_unique_lock2(MutexT1& m1, MutexT2& m2) :
Chris@16:         m_p1(&m1),
Chris@16:         m_p2(&m2)
Chris@16:     {
Chris@16:         // Yes, it's not conforming, but it works
Chris@16:         // and it doesn't require to #include <functional>
Chris@16:         if (static_cast< void* >(m_p1) < static_cast< void* >(m_p2))
Chris@16:         {
Chris@16:             m_p1->lock();
Chris@16:             m_p2->lock();
Chris@16:         }
Chris@16:         else
Chris@16:         {
Chris@16:             m_p2->lock();
Chris@16:             m_p1->lock();
Chris@16:         }
Chris@16:     }
Chris@16:     ~multiple_unique_lock2()
Chris@16:     {
Chris@16:         m_p2->unlock();
Chris@16:         m_p1->unlock();
Chris@16:     }
Chris@16: 
Chris@16: private:
Chris@16:     MutexT1* m_p1;
Chris@16:     MutexT2* m_p2;
Chris@16: };
Chris@16: 
Chris@16: #endif // BOOST_LOG_NO_THREADS
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_LOCKS_HPP_INCLUDED_