Logger.hpp

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/*
 * Logger.hpp
 *
 * Copyright (C) 2012 Evidence Srl - www.evidence.eu.com
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
 */

#ifndef LOGGER_HPP_
#define LOGGER_HPP_

#include <fstream>
#include <ostream>
#include <string>
#include <sstream>
#include <sys/time.h>

/// Comment this line if you don't need multithread support
#define LOG_MULTITHREAD

/// Log levels:
#define LOG_NOLOG       0 ///< No logging
#define LOG_ERRORS      1 ///< Log only error messages
#define LOG_WARNINGS    2 ///< Log warnings and error messages
#define LOG_ALL         3 ///< Log all

/// Log level for console messages:
#ifndef LOG_LEVEL_CONSOLE
#define LOG_LEVEL_CONSOLE       LOG_WARNINGS
#endif

/// Log level for file:
#ifndef LOG_LEVEL_FILE
#define LOG_LEVEL_FILE          LOG_ALL
#endif



#ifdef LOG_MULTITHREAD
#include "PosixMutex.hpp"
#endif

/**
 * \brief Macro to set the file used for logging.
 *
 * @param Base name of the file used for logging (e.g. "/tmp/myproject")
 *
 * Example of configuration of the Logger: *
 * \code
 *      LOG_FILE("/tmp/myproject);
 * \endcode
 */
#define LOG_FILE(outputFile) { \
        onposix::Logger::getInstance().setFile(outputFile); \
        }



/**
 * \brief Macro to print error messages.
 *
 * Example of usage:
 * \code
 *      ERROR("hello " << "world");
 * \endcode
 */
#if (defined NDEBUG) || (LOG_LEVEL_CONSOLE < LOG_ERRORS && LOG_LEVEL_FILE < LOG_ERRORS)
        #define ERROR(...)
#elif (LOG_LEVEL_CONSOLE < LOG_ERRORS)
        #define ERROR(msg) { \
                std::ostringstream logger_dbg_stream__; \
                logger_dbg_stream__ << "[ERROR]\t"; \
                logger_dbg_stream__ << msg; \
                onposix::Logger::getInstance().printOnFile(__FILE__, __LINE__, \
                                logger_dbg_stream__.str()); \
                }
#elif (LOG_LEVEL_FILE < LOG_ERRORS)
        #define ERROR(msg) { \
                std::ostringstream logger_dbg_stream__; \
                logger_dbg_stream__ << "[ERROR]\t"; \
                logger_dbg_stream__ << msg; \
                onposix::Logger::getInstance().printOnConsole(__FILE__, __LINE__, \
                                logger_dbg_stream__.str()); \
                }
#else
        #define ERROR(msg) { \
                std::ostringstream logger_dbg_stream__; \
                logger_dbg_stream__ << "[ERROR]\t"; \
                logger_dbg_stream__ << msg; \
                onposix::Logger::getInstance().printOnConsole(__FILE__, __LINE__, \
                                logger_dbg_stream__.str()); \
                onposix::Logger::getInstance().printOnFile(__FILE__, __LINE__, \
                                logger_dbg_stream__.str()); \
                }
#endif
        

/**
 * \brief Macro to print warning messages.
 *
 * Example of usage:
 * \code
 *      WARNING("hello " << "world");
 * \endcode
 */
#if (defined NDEBUG) || (LOG_LEVEL_CONSOLE < LOG_WARNINGS && LOG_LEVEL_FILE < LOG_WARNINGS)
        #define WARNING(...)
#elif (LOG_LEVEL_CONSOLE < LOG_WARNINGS)
        #define WARNING(msg) { \
                std::ostringstream logger_dbg_stream__; \
                logger_dbg_stream__ << "[WARNING]\t"; \
                logger_dbg_stream__ << msg; \
                onposix::Logger::getInstance().printOnFile(__FILE__, __LINE__, \
                                logger_dbg_stream__.str()); \
                }
#elif (LOG_LEVEL_FILE < LOG_WARNINGS)
        #define WARNING(msg) { \
                std::ostringstream logger_dbg_stream__; \
                logger_dbg_stream__ << "[WARNING]\t"; \
                logger_dbg_stream__ << msg; \
                onposix::Logger::getInstance().printOnConsole(__FILE__, __LINE__, \
                                logger_dbg_stream__.str()); \
                }
#else
        #define WARNING(msg) { \
                std::ostringstream logger_dbg_stream__; \
                logger_dbg_stream__ << "[WARNING]\t"; \
                logger_dbg_stream__ << msg; \
                onposix::Logger::getInstance().printOnConsole(__FILE__, __LINE__, \
                                logger_dbg_stream__.str()); \
                onposix::Logger::getInstance().printOnFile(__FILE__, __LINE__, \
                                logger_dbg_stream__.str()); \
                }
#endif



/**
 * \brief Macro to print debug messages.
 *
 * Example of usage:
 * \code
 *      DEBUG("hello " << "world");
 * \endcode
 */
#if (defined NDEBUG) || (LOG_LEVEL_CONSOLE < LOG_ALL && LOG_LEVEL_FILE < LOG_ALL)
        #define DEBUG(...)
#elif (LOG_LEVEL_CONSOLE < LOG_ALL)
        #define DEBUG(msg) { \
                std::ostringstream logger_dbg_stream__; \
                logger_dbg_stream__ << "[DEBUG]\t"; \
                logger_dbg_stream__ << msg; \
                onposix::Logger::getInstance().printOnFile(__FILE__, __LINE__, \
                                logger_dbg_stream__.str()); \
                }
#elif (LOG_LEVEL_FILE < LOG_ALL)
        #define DEBUG(msg) { \
                std::ostringstream logger_dbg_stream__; \
                logger_dbg_stream__ << "[DEBUG]\t"; \
                logger_dbg_stream__ << msg; \
                onposix::Logger::getInstance().printOnConsole(__FILE__, __LINE__, \
                                logger_dbg_stream__.str()); \
                }
#else
        #define DEBUG(msg) { \
                std::ostringstream logger_dbg_stream__; \
                logger_dbg_stream__ << "[DEBUG]\t"; \
                logger_dbg_stream__ << msg; \
                onposix::Logger::getInstance().printOnConsole(__FILE__, __LINE__, \
                                logger_dbg_stream__.str()); \
                onposix::Logger::getInstance().printOnFile(__FILE__, __LINE__, \
                                logger_dbg_stream__.str()); \
                }
#endif


namespace onposix {

/**
 * \brief Simple logger to log messages on file and console.
 *
 * This is the implementation of a simple logger in C++. It is implemented 
 * as a Singleton, so it can be easily called through the DEBUG, WARNING
 * and ERROR macros.
 * It is Pthread-safe.
 * It allows to log on both file and console.
 *
 * Example of configuration of the Logger: *
 * \code
 *      LOG_FILE("/tmp/myproject);
 * \endcode
 *
 * Example of usage of the Logger:
 * \code
 *      DEBUG("hello " << "world");
 * \endcode
 */
class Logger
{
public:
        static Logger& getInstance();

        void printOnFile(       const std::string&      sourceFile,
                                const int               codeLine,
                                const std::string&      message);
        void printOnConsole(    const std::string&      sourceFile,
                                const int               codeLine,
                                const std::string&      message);

        void setFile (const std::string&        outputFile);

        /**
         * \brief Method to know if the latest message has been printed on file
         *
         * @return true if it has been printed; false otherwise
         */
        inline bool latestMsgPrintedOnFile() const {
                return latestMsgPrintedOnFile_;
        }

        /**
         * \brief Method to know if the latest message has been printed on file
         *
         * @return true if it has been printed; false otherwise
         */
        inline bool latestMsgPrintedOnConsole() const {
                return latestMsgPrintedOnConsole_;
        }

private:
        Logger();
        ~Logger();

#ifdef LOG_MULTITHREAD
        /**
         * \brief Lock for mutual exclusion between different threads
         */
        static PosixMutex lock_;
#endif

        /**
         * \brief Pointer to the unique Logger (i.e., Singleton)
         */
        static Logger* m_;

        /**
         * \brief Initial part of the name of the file used for Logging.
         *
         * Date and time are automatically appended.
         */
        std::string logFile_;

        /**
         * \brief Stream used when logging on a file
         */
        std::ofstream out_;

        /**
         * \brief Initial time (used to print relative times)
         */
        struct timeval initialTime_;

        /**
         * \brief Debug: to know if the latest message has been printed
         * on file.
         */
        bool latestMsgPrintedOnFile_;

        /**
         * \brief Debug: to know if the latest message has been printed 
         * on console.
         */
        bool latestMsgPrintedOnConsole_;

        /**
         * \brief Method to lock in case of multithreading
         */
        inline static void lock();

        /**
         * \brief Method to unlock in case of multithreading
         */
        inline static void unlock();
};

} /* onposix */

#endif /* LOGGER_HPP_ */