boost/log/sinks/sink.hpp
/*
* 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 sink.hpp
* \author Andrey Semashev
* \date 22.04.2007
*
* The header contains an interface declaration for all sinks. This interface is used by the
* logging core to feed log records to sinks.
*/
#ifndef BOOST_LOG_SINKS_SINK_HPP_INCLUDED_
#define BOOST_LOG_SINKS_SINK_HPP_INCLUDED_
#include <string>
#include <boost/log/detail/config.hpp>
#include <boost/log/detail/light_function.hpp>
#include <boost/log/core/record_view.hpp>
#include <boost/log/attributes/attribute_value_set.hpp>
#include <boost/log/detail/header.hpp>
#ifdef BOOST_HAS_PRAGMA_ONCE
#pragma once
#endif
namespace boost {
BOOST_LOG_OPEN_NAMESPACE
namespace sinks {
//! A base class for a logging sink frontend
class BOOST_LOG_NO_VTABLE sink
{
public:
//! An exception handler type
typedef boost::log::aux::light_function< void () > exception_handler_type;
private:
//! The flag indicates that the sink passes log records across thread boundaries
const bool m_cross_thread;
public:
/*!
* Default constructor
*/
explicit sink(bool cross_thread) : m_cross_thread(cross_thread)
{
}
/*!
* Virtual destructor
*/
virtual ~sink() {}
/*!
* The method returns \c true if no filter is set or the attribute values pass the filter
*
* \param attributes A set of attribute values of a logging record
*/
virtual bool will_consume(attribute_value_set const& attributes) = 0;
/*!
* The method puts logging record to the sink
*
* \param rec Logging record to consume
*/
virtual void consume(record_view const& rec) = 0;
/*!
* The method attempts to put logging record to the sink. The method may be used by the
* core in order to determine the most efficient order of sinks to feed records to in
* case of heavy contention. Sink implementations may implement try/backoff logic in
* order to improve overall logging throughput.
*
* \param rec Logging record to consume
* \return \c true, if the record was consumed, \c false, if not.
*/
virtual bool try_consume(record_view const& rec)
{
consume(rec);
return true;
}
/*!
* The method performs flushing of any internal buffers that may hold log records. The method
* may take considerable time to complete and may block both the calling thread and threads
* attempting to put new records into the sink while this call is in progress.
*/
virtual void flush() = 0;
/*!
* The method indicates that the sink passes log records between different threads. This information is
* needed by the logging core to detach log records from all thread-specific resources before passing it
* to the sink.
*/
bool is_cross_thread() const BOOST_NOEXCEPT { return m_cross_thread; }
BOOST_DELETED_FUNCTION(sink(sink const&))
BOOST_DELETED_FUNCTION(sink& operator= (sink const&))
};
} // namespace sinks
BOOST_LOG_CLOSE_NAMESPACE // namespace log
} // namespace boost
#include <boost/log/detail/footer.hpp>
#endif // BOOST_LOG_SINKS_SINK_HPP_INCLUDED_