libs/log/example/doc/extension_formatter_parser.cpp

   1 /*
   2  *          Copyright Andrey Semashev 2007 - 2014.
   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/format.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/sources/logger.hpp>
  19 #include <boost/log/sources/record_ostream.hpp>
  20 #include <boost/log/utility/value_ref.hpp>
  21 #include <boost/log/utility/formatting_ostream.hpp>
  22 #include <boost/log/utility/manipulators/add_value.hpp>
  23 #include <boost/log/utility/setup/formatter_parser.hpp>
  24 #include <boost/log/utility/setup/common_attributes.hpp>
  25 #include <boost/log/utility/setup/console.hpp>
  26
  27 namespace logging = boost::log;
  28 namespace attrs = boost::log::attributes;
  29 namespace src = boost::log::sources;
  30 namespace expr = boost::log::expressions;
  31 namespace sinks = boost::log::sinks;
  32 namespace keywords = boost::log::keywords;
  33
  34 //[ example_extension_formatter_parser_point_definition
  35 struct point
  36 {
  37     float m_x, m_y;
  38
  39     point() : m_x(0.0f), m_y(0.0f) {}
  40     point(float x, float y) : m_x(x), m_y(y) {}
  41 };
  42
  43 template< typename CharT, typename TraitsT >
  44 std::basic_ostream< CharT, TraitsT >& operator<< (std::basic_ostream< CharT, TraitsT >& strm, point const& p)
  45 {
  46     strm << "(" << p.m_x << ", " << p.m_y << ")";
  47     return strm;
  48 }
  49 //]
  50
  51 #if 0
  52 //[ example_extension_simple_formatter_factory
  53 void init_factories()
  54 {
  55     logging::register_simple_formatter_factory< point, char >("Coordinates");
  56 }
  57 //]
  58 #endif
  59
  60 //[ example_extension_custom_formatter_factory
  61 // Custom point formatter
  62 class point_formatter
  63 {
  64 public:
  65     typedef void result_type;
  66
  67 public:
  68     explicit point_formatter(std::string const& fmt) : m_format(fmt)
  69     {
  70     }
  71
  72     void operator() (logging::formatting_ostream& strm, logging::value_ref< point > const& value) const
  73     {
  74         if (value)
  75         {
  76             point const& p = value.get();
  77             m_format % p.m_x % p.m_y;
  78             strm << m_format;
  79             m_format.clear();
  80         }
  81     }
  82
  83 private:
  84     mutable boost::format m_format;
  85 };
  86
  87 // Custom point formatter factory
  88 class point_formatter_factory :
  89     public logging::basic_formatter_factory< char, point >
  90 {
  91 public:
  92     formatter_type create_formatter(logging::attribute_name const& name, args_map const& args)
  93     {
  94         args_map::const_iterator it = args.find("format");
  95         if (it != args.end())
  96             return boost::phoenix::bind(point_formatter(it->second), expr::stream, expr::attr< point >(name));
  97         else
  98             return expr::stream << expr::attr< point >(name);
  99     }
 100 };
 101
 102 void init_factories()
 103 {
 104     logging::register_formatter_factory("Coordinates", boost::make_shared< point_formatter_factory >());
 105 }
 106 //]
 107
 108 void init_logging()
 109 {
 110     init_factories();
 111
 112     logging::add_console_log(std::clog, keywords::format = "%TimeStamp% %Coordinates(format=\"{%0.3f; %0.3f}\")% %Message%");
 113
 114     logging::add_common_attributes();
 115 }
 116
 117 int main(int, char*[])
 118 {
 119     init_logging();
 120
 121     src::logger lg;
 122     BOOST_LOG(lg) << logging::add_value("Coordinates", point(10.5f, 20.2f)) << "Hello, world with coordinates!";
 123
 124     return 0;
 125 }