Logger.h

/*
 * Copyright (c) 2019, Automatak LLC
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification, are permitted provided that the
 * following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following
 * disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following
 * disclaimer in the documentation and/or other materials provided with the distribution.
 *
 * 3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote
 * products derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
 * USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
#ifndef LOG4CPP_LOGGER_H
#define LOG4CPP_LOGGER_H

#include "log4cpp/ILogHandler.h"
#include "log4cpp/Strings.h"

#include <memory>
#include <string>

namespace log4cpp
{

const uint32_t max_log_entry_size = 120;

/**
 * A copyable facade over a LogRoot class
 */
class Logger
{
public:
        struct Settings
        {
                Settings(ModuleId module, const std::string& id, LogLevels levels) : module(module), id(id), levels(levels)
                {}

                ModuleId module;
                std::string id;
                LogLevels levels;
        };

        Logger(const std::shared_ptr<ILogHandler>& backend, ModuleId moduleid, const std::string& id, LogLevels levels) :
                backend(backend),
                settings(std::make_shared<Settings>(moduleid, id, levels))
        {}

        static Logger empty()
        {
                return Logger(nullptr, ModuleId(0), "", LogLevels(0));
        }

        void log(const LogLevel& level, const char* location, const char* message)
        {
                if (backend)
                {
                        backend->log(   
                                        this->settings->module,
                                        this->settings->id.c_str(),
                                        level,
                                        location,
                                        message                                 
                        );
                }
        }

        Logger detach(const std::string& id) const
        {
                return Logger(this->backend, std::make_shared<Settings>(this->settings->module, id, this->settings->levels));
        }

        template <typename... Args>
        Logger detach_and_append(Args... args) const
        {                       
                return detach(Strings::concatenate(this->settings->id, args...));
        }

        Logger detach(const std::string& id, LogLevels levels) const
        {
                return Logger(this->backend, std::make_shared<Settings>(this->settings->module, id, levels));
        }

        Logger detach(LogLevels levels) const
        {
                return Logger(this->backend, std::make_shared<Settings>(this->settings->module, this->settings->id, levels));
        }

        bool is_enabled(const LogLevel& level) const
        {
                return backend && settings->levels.is_set(level);
        }

        LogLevels get_levels() const
        {
                return this->settings->levels;
        }

        void set_levels(const LogLevels& filters)
        {
                this->settings->levels = filters;
        }

        void rename(const std::string& id)
        {
                this->settings->id = id;
        }

private:
        Logger(const std::shared_ptr<ILogHandler>& backend, const std::shared_ptr<Settings>& settings) :
                backend(backend),
                settings(settings)
        {}

        Logger() = delete;
        Logger& operator=(const Logger&) = delete;

        const std::shared_ptr<ILogHandler> backend;
        const std::shared_ptr<Settings> settings;
};

} //namespace log4cpp

#endif //LOG4CPP_LOGGER_H