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/*
* Copyright Andrey Semashev 2007 - 2015.
* Distributed under 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)
*/
/*!
* \file utility/strictest_lock.hpp
* \author Andrey Semashev
* \date 30.05.2010
*
* The header contains definition of the \c strictest_lock metafunction that
* allows to select a lock with the strictest access requirements.
*/
#ifndef BOOST_LOG_UTILITY_STRICTEST_LOCK_HPP_INCLUDED_
#define BOOST_LOG_UTILITY_STRICTEST_LOCK_HPP_INCLUDED_
#include <boost/mpl/integral_c.hpp>
#include <boost/log/detail/config.hpp>
#include <boost/log/detail/locks.hpp>
#if defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
#include <boost/preprocessor/cat.hpp>
#include <boost/preprocessor/arithmetic/sub.hpp>
#include <boost/preprocessor/arithmetic/inc.hpp>
#include <boost/preprocessor/arithmetic/dec.hpp>
#include <boost/preprocessor/repetition/enum_trailing.hpp>
#include <boost/preprocessor/repetition/enum_params_with_a_default.hpp>
#include <boost/log/detail/pp_identity.hpp>
#endif
#if defined(BOOST_LOG_BROKEN_CONSTANT_EXPRESSIONS)
#include <boost/mpl/less.hpp>
#endif
#include <boost/log/detail/header.hpp>
#ifdef BOOST_HAS_PRAGMA_ONCE
#pragma once
#endif
#if defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
#if !defined(BOOST_LOG_STRICTEST_LOCK_LIMIT)
/*!
* The macro defines the maximum number of template arguments that the \c strictest_lock
* metafunction accepts. Should not be less than 2.
*/
#define BOOST_LOG_STRICTEST_LOCK_LIMIT 10
#endif // BOOST_LOG_STRICTEST_LOCK_LIMIT
#if BOOST_LOG_STRICTEST_LOCK_LIMIT < 2
#error The BOOST_LOG_STRICTEST_LOCK_LIMIT macro should not be less than 2
#endif
#endif // defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
namespace boost {
BOOST_LOG_OPEN_NAMESPACE
//! Access modes for different types of locks
enum lock_access_mode
{
unlocked_access, //!< A thread that owns this kind of lock doesn't restrict other threads in any way
shared_access, //!< A thread that owns this kind of lock requires that no other thread modify the locked data
exclusive_access //!< A thread that owns this kind of lock requires that no other thread has access to the locked data
};
//! The trait allows to select an access mode by the lock type
template< typename LockT >
struct thread_access_mode_of;
template< typename MutexT >
struct thread_access_mode_of< no_lock< MutexT > > : mpl::integral_c< lock_access_mode, unlocked_access >
{
};
#if !defined(BOOST_LOG_NO_THREADS)
template< typename MutexT >
struct thread_access_mode_of< lock_guard< MutexT > > : mpl::integral_c< lock_access_mode, exclusive_access >
{
};
template< typename MutexT >
struct thread_access_mode_of< shared_lock_guard< MutexT > > : mpl::integral_c< lock_access_mode, shared_access >
{
};
template< typename MutexT >
struct thread_access_mode_of< unique_lock< MutexT > > : mpl::integral_c< lock_access_mode, exclusive_access >
{
};
template< typename MutexT >
struct thread_access_mode_of< shared_lock< MutexT > > : mpl::integral_c< lock_access_mode, shared_access >
{
};
template< typename MutexT >
struct thread_access_mode_of< upgrade_lock< MutexT > > : mpl::integral_c< lock_access_mode, shared_access >
{
};
template< typename MutexT >
struct thread_access_mode_of< boost::log::aux::exclusive_lock_guard< MutexT > > : mpl::integral_c< lock_access_mode, exclusive_access >
{
};
template< typename MutexT >
struct thread_access_mode_of< boost::log::aux::shared_lock_guard< MutexT > > : mpl::integral_c< lock_access_mode, shared_access >
{
};
#endif // !defined(BOOST_LOG_NO_THREADS)
namespace aux {
//! The metafunction selects the most strict lock type of the two
template<
typename LeftLockT,
typename RightLockT,
#if !defined(BOOST_LOG_BROKEN_CONSTANT_EXPRESSIONS)
bool CondV = (thread_access_mode_of< LeftLockT >::value < thread_access_mode_of< RightLockT >::value)
#else
bool CondV = mpl::less< thread_access_mode_of< LeftLockT >, thread_access_mode_of< RightLockT > >::value
#endif
>
struct strictest_lock_impl
{
typedef RightLockT type;
};
template< typename LeftLockT, typename RightLockT >
struct strictest_lock_impl< LeftLockT, RightLockT, false >
{
typedef LeftLockT type;
};
} // namespace aux
#if defined(BOOST_LOG_DOXYGEN_PASS)
/*!
* \brief The metafunction selects the most strict lock type of the specified.
*
* The template supports all lock types provided by the Boost.Thread
* library (except for \c upgrade_to_unique_lock), plus additional
* pseudo-lock \c no_lock that indicates no locking at all.
* Exclusive locks are considered the strictest, shared locks are weaker,
* and \c no_lock is the weakest.
*/
template< typename... LocksT >
struct strictest_lock
{
typedef implementation_defined type;
};
#else // defined(BOOST_LOG_DOXYGEN_PASS)
#if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
template< typename LockT, typename... LocksT >
struct strictest_lock;
template< typename LockT >
struct strictest_lock< LockT >
{
typedef LockT type;
};
template< typename LeftLockT, typename RightLockT >
struct strictest_lock< LeftLockT, RightLockT >
{
typedef typename aux::strictest_lock_impl< LeftLockT, RightLockT >::type type;
};
template< typename LeftLockT, typename RightLockT, typename... LocksT >
struct strictest_lock< LeftLockT, RightLockT, LocksT... >
{
typedef typename strictest_lock<
typename aux::strictest_lock_impl< LeftLockT, RightLockT >::type,
LocksT...
>::type type;
};
#else // !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
# define BOOST_LOG_TYPE_INTERNAL(z, i, data) BOOST_PP_CAT(T, BOOST_PP_INC(i))
template<
typename T,
BOOST_PP_ENUM_PARAMS_WITH_A_DEFAULT(BOOST_PP_DEC(BOOST_LOG_STRICTEST_LOCK_LIMIT), typename T, void)
>
struct strictest_lock
{
typedef typename strictest_lock<
typename boost::log::aux::strictest_lock_impl< T, T0 >::type
BOOST_PP_ENUM_TRAILING(BOOST_PP_SUB(BOOST_LOG_STRICTEST_LOCK_LIMIT, 2), BOOST_LOG_TYPE_INTERNAL, ~)
>::type type;
};
template< typename T >
struct strictest_lock<
T
BOOST_PP_ENUM_TRAILING(BOOST_PP_DEC(BOOST_LOG_STRICTEST_LOCK_LIMIT), BOOST_LOG_PP_IDENTITY, void)
>
{
typedef T type;
};
# undef BOOST_LOG_TYPE_INTERNAL
#endif // !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
#endif // defined(BOOST_LOG_DOXYGEN_PASS)
BOOST_LOG_CLOSE_NAMESPACE // namespace log
} // namespace boost
#include <boost/log/detail/footer.hpp>
#endif // BOOST_LOG_UTILITY_STRICTEST_LOCK_HPP_INCLUDED_
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