ceph/src/boost/libs/log/include/boost/log/sinks/sink.hpp

   1 /*
   2  *          Copyright Andrey Semashev 2007 - 2015.
   3  * Distributed under the Boost Software License, Version 1.0.
   4  *    (See accompanying file LICENSE_1_0.txt or copy at
   5  *          http://www.boost.org/LICENSE_1_0.txt)
   6  */
   7 /*!
   8  * \file   sink.hpp
   9  * \author Andrey Semashev
  10  * \date   22.04.2007
  11  *
  12  * The header contains an interface declaration for all sinks. This interface is used by the
  13  * logging core to feed log records to sinks.
  14  */
  15
  16 #ifndef BOOST_LOG_SINKS_SINK_HPP_INCLUDED_
  17 #define BOOST_LOG_SINKS_SINK_HPP_INCLUDED_
  18
  19 #include <string>
  20 #include <boost/log/detail/config.hpp>
  21 #include <boost/log/detail/light_function.hpp>
  22 #include <boost/log/core/record_view.hpp>
  23 #include <boost/log/attributes/attribute_value_set.hpp>
  24 #include <boost/log/detail/header.hpp>
  25
  26 #ifdef BOOST_HAS_PRAGMA_ONCE
  27 #pragma once
  28 #endif
  29
  30 namespace boost {
  31
  32 BOOST_LOG_OPEN_NAMESPACE
  33
  34 namespace sinks {
  35
  36 //! A base class for a logging sink frontend
  37 class BOOST_LOG_NO_VTABLE sink
  38 {
  39 public:
  40     //! An exception handler type
  41     typedef boost::log::aux::light_function< void () > exception_handler_type;
  42
  43 private:
  44     //! The flag indicates that the sink passes log records across thread boundaries
  45     const bool m_cross_thread;
  46
  47 public:
  48     /*!
  49      * Default constructor
  50      */
  51     explicit sink(bool cross_thread) : m_cross_thread(cross_thread)
  52     {
  53     }
  54
  55     /*!
  56      * Virtual destructor
  57      */
  58     virtual ~sink() {}
  59
  60     /*!
  61      * The method returns \c true if no filter is set or the attribute values pass the filter
  62      *
  63      * \param attributes A set of attribute values of a logging record
  64      */
  65     virtual bool will_consume(attribute_value_set const& attributes) = 0;
  66
  67     /*!
  68      * The method puts logging record to the sink
  69      *
  70      * \param rec Logging record to consume
  71      */
  72     virtual void consume(record_view const& rec) = 0;
  73
  74     /*!
  75      * The method attempts to put logging record to the sink. The method may be used by the
  76      * core in order to determine the most efficient order of sinks to feed records to in
  77      * case of heavy contention. Sink implementations may implement try/backoff logic in
  78      * order to improve overall logging throughput.
  79      *
  80      * \param rec Logging record to consume
  81      * \return \c true, if the record was consumed, \c false, if not.
  82      */
  83     virtual bool try_consume(record_view const& rec)
  84     {
  85         consume(rec);
  86         return true;
  87     }
  88
  89     /*!
  90      * The method performs flushing of any internal buffers that may hold log records. The method
  91      * may take considerable time to complete and may block both the calling thread and threads
  92      * attempting to put new records into the sink while this call is in progress.
  93      */
  94     virtual void flush() = 0;
  95
  96     /*!
  97      * The method indicates that the sink passes log records between different threads. This information is
  98      * needed by the logging core to detach log records from all thread-specific resources before passing it
  99      * to the sink.
 100      */
 101     bool is_cross_thread() const BOOST_NOEXCEPT { return m_cross_thread; }
 102
 103     BOOST_DELETED_FUNCTION(sink(sink const&))
 104     BOOST_DELETED_FUNCTION(sink& operator= (sink const&))
 105 };
 106
 107 } // namespace sinks
 108
 109 BOOST_LOG_CLOSE_NAMESPACE // namespace log
 110
 111 } // namespace boost
 112
 113 #include <boost/log/detail/footer.hpp>
 114
 115 #endif // BOOST_LOG_SINKS_SINK_HPP_INCLUDED_