ceph/src/boost/libs/log/example/doc/extension_filter_parser.cpp

   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 #include <string>
   9 #include <iostream>
  10 #include <stdexcept>
  11 #include <boost/smart_ptr/shared_ptr.hpp>
  12 #include <boost/smart_ptr/make_shared_object.hpp>
  13 #include <boost/lexical_cast.hpp>
  14 #include <boost/phoenix.hpp>
  15 #include <boost/log/core.hpp>
  16 #include <boost/log/expressions.hpp>
  17 #include <boost/log/attributes/attribute_name.hpp>
  18 #include <boost/log/attributes/scoped_attribute.hpp>
  19 #include <boost/log/sources/logger.hpp>
  20 #include <boost/log/sources/record_ostream.hpp>
  21 #include <boost/log/utility/value_ref.hpp>
  22 #include <boost/log/utility/formatting_ostream.hpp>
  23 #include <boost/log/utility/manipulators/add_value.hpp>
  24 #include <boost/log/utility/setup/filter_parser.hpp>
  25 #include <boost/log/utility/setup/common_attributes.hpp>
  26 #include <boost/log/utility/setup/console.hpp>
  27
  28 namespace logging = boost::log;
  29 namespace attrs = boost::log::attributes;
  30 namespace src = boost::log::sources;
  31 namespace expr = boost::log::expressions;
  32 namespace sinks = boost::log::sinks;
  33 namespace keywords = boost::log::keywords;
  34
  35 //[ example_extension_filter_parser_point_definition
  36 struct point
  37 {
  38     float m_x, m_y;
  39
  40     point() : m_x(0.0f), m_y(0.0f) {}
  41     point(float x, float y) : m_x(x), m_y(y) {}
  42 };
  43
  44 bool operator== (point const& left, point const& right);
  45 bool operator!= (point const& left, point const& right);
  46
  47 template< typename CharT, typename TraitsT >
  48 std::basic_ostream< CharT, TraitsT >& operator<< (std::basic_ostream< CharT, TraitsT >& strm, point const& p);
  49 template< typename CharT, typename TraitsT >
  50 std::basic_istream< CharT, TraitsT >& operator>> (std::basic_istream< CharT, TraitsT >& strm, point& p);
  51 //]
  52
  53 const float epsilon = 0.0001f;
  54
  55 bool operator== (point const& left, point const& right)
  56 {
  57     return (left.m_x - epsilon <= right.m_x && left.m_x + epsilon >= right.m_x) &&
  58            (left.m_y - epsilon <= right.m_y && left.m_y + epsilon >= right.m_y);
  59 }
  60
  61 bool operator!= (point const& left, point const& right)
  62 {
  63     return !(left == right);
  64 }
  65
  66 template< typename CharT, typename TraitsT >
  67 std::basic_ostream< CharT, TraitsT >& operator<< (std::basic_ostream< CharT, TraitsT >& strm, point const& p)
  68 {
  69     if (strm.good())
  70         strm << "(" << p.m_x << ", " << p.m_y << ")";
  71     return strm;
  72 }
  73
  74 template< typename CharT, typename TraitsT >
  75 std::basic_istream< CharT, TraitsT >& operator>> (std::basic_istream< CharT, TraitsT >& strm, point& p)
  76 {
  77     if (strm.good())
  78     {
  79         CharT left_brace = static_cast< CharT >(0), comma = static_cast< CharT >(0), right_brace = static_cast< CharT >(0);
  80         strm.setf(std::ios_base::skipws);
  81         strm >> left_brace >> p.m_x >> comma >> p.m_y >> right_brace;
  82         if (left_brace != '(' || comma != ',' || right_brace != ')')
  83             strm.setstate(std::ios_base::failbit);
  84     }
  85     return strm;
  86 }
  87
  88 #if 0
  89 //[ example_extension_simple_filter_factory
  90 void init_factories()
  91 {
  92     //<-
  93     logging::register_simple_formatter_factory< point, char >("Coordinates");
  94     //->
  95     logging::register_simple_filter_factory< point, char >("Coordinates");
  96 }
  97 //]
  98 #endif
  99
 100 //[ example_extension_custom_filter_factory
 101 // Custom point filter factory
 102 class point_filter_factory :
 103     public logging::filter_factory< char >
 104 {
 105 public:
 106     logging::filter on_exists_test(logging::attribute_name const& name)
 107     {
 108         return expr::has_attr< point >(name);
 109     }
 110
 111     logging::filter on_equality_relation(logging::attribute_name const& name, string_type const& arg)
 112     {
 113         return expr::attr< point >(name) == boost::lexical_cast< point >(arg);
 114     }
 115
 116     logging::filter on_inequality_relation(logging::attribute_name const& name, string_type const& arg)
 117     {
 118         return expr::attr< point >(name) != boost::lexical_cast< point >(arg);
 119     }
 120 };
 121
 122 void init_factories()
 123 {
 124     //<-
 125     logging::register_simple_formatter_factory< point, char >("Coordinates");
 126     //->
 127     logging::register_filter_factory("Coordinates", boost::make_shared< point_filter_factory >());
 128 }
 129 //]
 130
 131 void init_logging()
 132 {
 133     init_factories();
 134
 135     logging::add_console_log
 136     (
 137         std::clog,
 138         keywords::filter = "%Coordinates% = \"(10, 10)\"",
 139         keywords::format = "%TimeStamp% %Coordinates% %Message%"
 140     );
 141
 142     logging::add_common_attributes();
 143 }
 144
 145 int main(int, char*[])
 146 {
 147     init_logging();
 148
 149     src::logger lg;
 150
 151     // We have to use scoped attributes in order coordinates to be passed to filters
 152     {
 153         BOOST_LOG_SCOPED_LOGGER_TAG(lg, "Coordinates", point(10, 10));
 154         BOOST_LOG(lg) << "Hello, world with coordinates (10, 10)!";
 155     }
 156     {
 157         BOOST_LOG_SCOPED_LOGGER_TAG(lg, "Coordinates", point(20, 20));
 158         BOOST_LOG(lg) << "Hello, world with coordinates (20, 20)!"; // this message will be suppressed by filter
 159     }
 160
 161     return 0;
 162 }