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   utility/strictest_lock.hpp
Chris@16:  * \author Andrey Semashev
Chris@16:  * \date   30.05.2010
Chris@16:  *
Chris@16:  * The header contains definition of the \c strictest_lock metafunction that
Chris@16:  * allows to select a lock with the strictest access requirements.
Chris@16:  */
Chris@16: 
Chris@16: #ifndef BOOST_LOG_UTILITY_STRICTEST_LOCK_HPP_INCLUDED_
Chris@16: #define BOOST_LOG_UTILITY_STRICTEST_LOCK_HPP_INCLUDED_
Chris@16: 
Chris@16: #include <boost/mpl/integral_c.hpp>
Chris@16: #include <boost/log/detail/config.hpp>
Chris@16: #include <boost/log/detail/locks.hpp>
Chris@16: #if defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
Chris@16: #include <boost/preprocessor/cat.hpp>
Chris@16: #include <boost/preprocessor/arithmetic/sub.hpp>
Chris@16: #include <boost/preprocessor/arithmetic/inc.hpp>
Chris@16: #include <boost/preprocessor/arithmetic/dec.hpp>
Chris@16: #include <boost/preprocessor/repetition/enum_trailing.hpp>
Chris@16: #include <boost/preprocessor/repetition/enum_params_with_a_default.hpp>
Chris@16: #include <boost/log/detail/pp_identity.hpp>
Chris@16: #endif
Chris@16: #if defined(BOOST_LOG_BROKEN_CONSTANT_EXPRESSIONS)
Chris@16: #include <boost/mpl/less.hpp>
Chris@16: #endif
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: #if defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
Chris@16: #if !defined(BOOST_LOG_STRICTEST_LOCK_LIMIT)
Chris@16: /*!
Chris@16:  * The macro defines the maximum number of template arguments that the \c strictest_lock
Chris@16:  * metafunction accepts. Should not be less than 2.
Chris@16:  */
Chris@16: #define BOOST_LOG_STRICTEST_LOCK_LIMIT 10
Chris@16: #endif // BOOST_LOG_STRICTEST_LOCK_LIMIT
Chris@16: #if BOOST_LOG_STRICTEST_LOCK_LIMIT < 2
Chris@16: #error The BOOST_LOG_STRICTEST_LOCK_LIMIT macro should not be less than 2
Chris@16: #endif
Chris@16: #endif // defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
Chris@16: 
Chris@16: namespace boost {
Chris@16: 
Chris@16: BOOST_LOG_OPEN_NAMESPACE
Chris@16: 
Chris@16: //! Access modes for different types of locks
Chris@16: enum lock_access_mode
Chris@16: {
Chris@16:     unlocked_access,    //!< A thread that owns this kind of lock doesn't restrict other threads in any way
Chris@16:     shared_access,      //!< A thread that owns this kind of lock requires that no other thread modify the locked data
Chris@16:     exclusive_access    //!< A thread that owns this kind of lock requires that no other thread has access to the locked data
Chris@16: };
Chris@16: 
Chris@16: //! The trait allows to select an access mode by the lock type
Chris@16: template< typename LockT >
Chris@16: struct thread_access_mode_of;
Chris@16: 
Chris@16: template< typename MutexT >
Chris@16: struct thread_access_mode_of< no_lock< MutexT > > : mpl::integral_c< lock_access_mode, unlocked_access >
Chris@16: {
Chris@16: };
Chris@16: 
Chris@16: #if !defined(BOOST_LOG_NO_THREADS)
Chris@16: 
Chris@16: template< typename MutexT >
Chris@16: struct thread_access_mode_of< lock_guard< MutexT > > : mpl::integral_c< lock_access_mode, exclusive_access >
Chris@16: {
Chris@16: };
Chris@16: 
Chris@16: template< typename MutexT >
Chris@16: struct thread_access_mode_of< unique_lock< MutexT > > : mpl::integral_c< lock_access_mode, exclusive_access >
Chris@16: {
Chris@16: };
Chris@16: 
Chris@16: template< typename MutexT >
Chris@16: struct thread_access_mode_of< shared_lock< MutexT > > : mpl::integral_c< lock_access_mode, shared_access >
Chris@16: {
Chris@16: };
Chris@16: 
Chris@16: template< typename MutexT >
Chris@16: struct thread_access_mode_of< upgrade_lock< MutexT > > : mpl::integral_c< lock_access_mode, shared_access >
Chris@16: {
Chris@16: };
Chris@16: 
Chris@16: template< typename MutexT >
Chris@16: struct thread_access_mode_of< boost::log::aux::exclusive_lock_guard< MutexT > > : mpl::integral_c< lock_access_mode, exclusive_access >
Chris@16: {
Chris@16: };
Chris@16: 
Chris@16: template< typename MutexT >
Chris@16: struct thread_access_mode_of< boost::log::aux::shared_lock_guard< MutexT > > : mpl::integral_c< lock_access_mode, shared_access >
Chris@16: {
Chris@16: };
Chris@16: 
Chris@16: #endif // !defined(BOOST_LOG_NO_THREADS)
Chris@16: 
Chris@16: namespace aux {
Chris@16: 
Chris@16: //! The metafunction selects the most strict lock type of the two
Chris@16: template<
Chris@16:     typename LeftLockT,
Chris@16:     typename RightLockT,
Chris@16: #if !defined(BOOST_LOG_BROKEN_CONSTANT_EXPRESSIONS)
Chris@16:     bool CondV = (thread_access_mode_of< LeftLockT >::value < thread_access_mode_of< RightLockT >::value)
Chris@16: #else
Chris@16:     bool CondV = mpl::less< thread_access_mode_of< LeftLockT >, thread_access_mode_of< RightLockT > >::value
Chris@16: #endif
Chris@16: >
Chris@16: struct strictest_lock_impl
Chris@16: {
Chris@16:     typedef RightLockT type;
Chris@16: };
Chris@16: template< typename LeftLockT, typename RightLockT >
Chris@16: struct strictest_lock_impl< LeftLockT, RightLockT, false >
Chris@16: {
Chris@16:     typedef LeftLockT type;
Chris@16: };
Chris@16: 
Chris@16: } // namespace aux
Chris@16: 
Chris@16: #if defined(BOOST_LOG_DOXYGEN_PASS)
Chris@16: 
Chris@16: /*!
Chris@16:  * \brief The metafunction selects the most strict lock type of the specified.
Chris@16:  *
Chris@16:  * The template supports all lock types provided by the Boost.Thread
Chris@16:  * library (except for \c upgrade_to_unique_lock), plus additional
Chris@16:  * pseudo-lock \c no_lock that indicates no locking at all.
Chris@16:  * Exclusive locks are considered the strictest, shared locks are weaker,
Chris@16:  * and \c no_lock is the weakest.
Chris@16:  */
Chris@16: template< typename... LocksT >
Chris@16: struct strictest_lock
Chris@16: {
Chris@16:     typedef implementation_defined type;
Chris@16: };
Chris@16: 
Chris@16: #else // defined(BOOST_LOG_DOXYGEN_PASS)
Chris@16: 
Chris@16: #if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
Chris@16: 
Chris@16: template< typename LockT, typename... LocksT >
Chris@16: struct strictest_lock;
Chris@16: 
Chris@16: template< typename LockT >
Chris@16: struct strictest_lock< LockT >
Chris@16: {
Chris@16:     typedef LockT type;
Chris@16: };
Chris@16: 
Chris@16: template< typename LeftLockT, typename RightLockT >
Chris@16: struct strictest_lock< LeftLockT, RightLockT >
Chris@16: {
Chris@16:     typedef typename aux::strictest_lock_impl< LeftLockT, RightLockT >::type type;
Chris@16: };
Chris@16: 
Chris@16: template< typename LeftLockT, typename RightLockT, typename... LocksT >
Chris@16: struct strictest_lock< LeftLockT, RightLockT, LocksT... >
Chris@16: {
Chris@16:     typedef typename strictest_lock<
Chris@16:         typename aux::strictest_lock_impl< LeftLockT, RightLockT >::type,
Chris@16:         LocksT...
Chris@16:     >::type type;
Chris@16: };
Chris@16: 
Chris@16: #else // !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
Chris@16: 
Chris@16: #   define BOOST_LOG_TYPE_INTERNAL(z, i, data) BOOST_PP_CAT(T, BOOST_PP_INC(i))
Chris@16: 
Chris@16: template<
Chris@16:     typename T,
Chris@16:     BOOST_PP_ENUM_PARAMS_WITH_A_DEFAULT(BOOST_PP_DEC(BOOST_LOG_STRICTEST_LOCK_LIMIT), typename T, void)
Chris@16: >
Chris@16: struct strictest_lock
Chris@16: {
Chris@16:     typedef typename strictest_lock<
Chris@16:         typename boost::log::aux::strictest_lock_impl< T, T0 >::type
Chris@16:         BOOST_PP_ENUM_TRAILING(BOOST_PP_SUB(BOOST_LOG_STRICTEST_LOCK_LIMIT, 2), BOOST_LOG_TYPE_INTERNAL, ~)
Chris@16:     >::type type;
Chris@16: };
Chris@16: 
Chris@16: template< typename T >
Chris@16: struct strictest_lock<
Chris@16:     T
Chris@16:     BOOST_PP_ENUM_TRAILING(BOOST_PP_DEC(BOOST_LOG_STRICTEST_LOCK_LIMIT), BOOST_LOG_PP_IDENTITY, void)
Chris@16: >
Chris@16: {
Chris@16:     typedef T type;
Chris@16: };
Chris@16: 
Chris@16: #   undef BOOST_LOG_TYPE_INTERNAL
Chris@16: 
Chris@16: #endif // !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
Chris@16: 
Chris@16: #endif // defined(BOOST_LOG_DOXYGEN_PASS)
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_UTILITY_STRICTEST_LOCK_HPP_INCLUDED_