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Diffstat (limited to 'boost/log/sinks/block_on_overflow.hpp')
-rw-r--r-- | boost/log/sinks/block_on_overflow.hpp | 147 |
1 files changed, 147 insertions, 0 deletions
diff --git a/boost/log/sinks/block_on_overflow.hpp b/boost/log/sinks/block_on_overflow.hpp new file mode 100644 index 0000000000..a23b5ff875 --- /dev/null +++ b/boost/log/sinks/block_on_overflow.hpp @@ -0,0 +1,147 @@ +/* + * Copyright Andrey Semashev 2007 - 2014. + * 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 block_on_overflow.hpp + * \author Andrey Semashev + * \date 04.01.2012 + * + * The header contains implementation of \c block_on_overflow strategy for handling + * queue overflows in bounded queues for the asynchronous sink frontend. + */ + +#ifndef BOOST_LOG_SINKS_BLOCK_ON_OVERFLOW_HPP_INCLUDED_ +#define BOOST_LOG_SINKS_BLOCK_ON_OVERFLOW_HPP_INCLUDED_ + +#include <boost/log/detail/config.hpp> + +#ifdef BOOST_HAS_PRAGMA_ONCE +#pragma once +#endif + +#if defined(BOOST_LOG_NO_THREADS) +#error Boost.Log: This header content is only supported in multithreaded environment +#endif + +#include <boost/intrusive/options.hpp> +#include <boost/intrusive/list.hpp> +#include <boost/intrusive/list_hook.hpp> +#include <boost/thread/condition_variable.hpp> +#include <boost/log/core/record_view.hpp> +#include <boost/log/detail/header.hpp> + +namespace boost { + +BOOST_LOG_OPEN_NAMESPACE + +namespace sinks { + +/*! + * \brief Blocking strategy for handling log record queue overflows + * + * This strategy will cause enqueueing threads to block when the + * log record queue overflows. The blocked threads will be woken as + * soon as there appears free space in the queue, in the same order + * they attempted to enqueue records. + */ +class block_on_overflow +{ +#ifndef BOOST_LOG_DOXYGEN_PASS +private: + typedef intrusive::list_base_hook< + intrusive::link_mode< intrusive::auto_unlink > + > thread_context_hook_t; + + struct thread_context : + public thread_context_hook_t + { + condition_variable cond; + bool result; + + thread_context() : result(true) {} + }; + + typedef intrusive::list< + thread_context, + intrusive::base_hook< thread_context_hook_t >, + intrusive::constant_time_size< false > + > thread_contexts; + +private: + //! Blocked threads + thread_contexts m_thread_contexts; + +public: + /*! + * Default constructor. + */ + BOOST_DEFAULTED_FUNCTION(block_on_overflow(), {}) + + /*! + * This method is called by the queue when overflow is detected. + * + * \param lock An internal lock that protects the queue + * + * \retval true Attempt to enqueue the record again. + * \retval false Discard the record. + */ + template< typename LockT > + bool on_overflow(record_view const&, LockT& lock) + { + thread_context context; + m_thread_contexts.push_back(context); + do + { + context.cond.wait(lock); + } + while (context.is_linked()); + + return context.result; + } + + /*! + * This method is called by the queue when there appears a free space. + * The internal lock protecting the queue is locked when calling this method. + */ + void on_queue_space_available() + { + if (!m_thread_contexts.empty()) + { + m_thread_contexts.front().cond.notify_one(); + m_thread_contexts.pop_front(); + } + } + + /*! + * This method is called by the queue to interrupt any possible waits in \c on_overflow. + * The internal lock protecting the queue is locked when calling this method. + */ + void interrupt() + { + while (!m_thread_contexts.empty()) + { + thread_context& context = m_thread_contexts.front(); + context.result = false; + context.cond.notify_one(); + m_thread_contexts.pop_front(); + } + } + + // Copying prohibited + BOOST_DELETED_FUNCTION(block_on_overflow(block_on_overflow const&)) + BOOST_DELETED_FUNCTION(block_on_overflow& operator= (block_on_overflow const&)) +#endif // BOOST_LOG_DOXYGEN_PASS +}; + +} // namespace sinks + +BOOST_LOG_CLOSE_NAMESPACE // namespace log + +} // namespace boost + +#include <boost/log/detail/footer.hpp> + +#endif // BOOST_LOG_SINKS_BLOCK_ON_OVERFLOW_HPP_INCLUDED_ |