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 */ sink(bool cross_thread)51 explicit sink(bool cross_thread) : m_cross_thread(cross_thread) 52 { 53 } 54 55 /*! 56 * Virtual destructor 57 */ ~sink()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 */ try_consume(record_view const & rec)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 */ is_cross_thread() const101 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_ 116