cpp-logger/include/logger/logger.h

//
//  logger.hpp
//  logger
//
//  Created by Sam Jaffe on 9/3/16.
//

#pragma once

//
//  Logger.hpp
//  DanmakuRPG
//
//  Created by Sam Jaffe on 7/18/15.
//  Copyright (c) 2015 Sam Jaffe. All rights reserved.
//

#pragma once

#include <cstdarg>
#include <cstdlib>
#include <cstring>
#include <memory>
#include <string>

#include "message.h"

#define log_message(logger, lvl, ...)                                          \
  logger.log(level::lvl, log_here, __VA_ARGS__)

namespace logging {
  enum class level : int;
  struct location_info;
  class logger_impl;
  struct logpacket;

  /*
   * The main top-level class that should be used when performing logging.
   * Provides various overrides of the function log() that handle various use
   * cases. In comparison with the C-Style logger, this one uses a Python style
   * of string formatting.
   * Currently, it is only able to support "{}", and cannot use positional,
   * named, or reflection-based interpolations. Under the hood, the loggers are
   * configured in a similar fashion to those in Log4J, such as PatternLayout
   * and FileAppender.
   * One of the useful features of this logger is the log_here macro. Log here
   * uses the compiler to generate all of the necessary information for file
   * name, class/namespace path, method name, and line number. It is not
   * supported for the logger to learn that information on its own through
   * creating a backtrace.
   */
  class logger {
  private:
    friend class manager;
    std::string const logger_name_;
    std::shared_ptr<logger_impl> impl_;

  public:
    ~logger();

    void log(level ll, char const * str) { log(ll, message(str)); }
    void log(level ll, std::string const & str) { log(ll, message(str)); }

    template <typename... Args>
    void log(level ll, std::string const & interp, Args &&... args) {
      log(ll, message(interp, std::forward<Args>(args)...));
    }

    template <typename... Args>
    void log(level ll, location_info const & info, std::string const & interp,
             Args &&... args) {
      log(ll, info, message(interp, std::forward<Args>(args)...));
    }

    void flush();

  protected:
    logger(std::string const & name, std::shared_ptr<logger_impl> impl);

  private:
    void log(level ll, message const &);
    void log(level ll, location_info const & info, message const &);
  };
}