cpp-logger/include/logger/c_logger.h

//
//  c_logger.hpp
//  logging
//
//  Created by Sam Jaffe on 4/1/19.
//

#pragma once

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

#include "level.h"

#define VA_LOGN(level, size)                                                   \
  do {                                                                         \
    va_list vargs;                                                             \
    va_start(vargs, fmt);                                                      \
    vlognf(level, size, fmt, vargs);                                           \
    va_end(vargs);                                                             \
  } while (0)

#define VA_LOG(level) VA_LOGN(level, c_logger::LOGF_MAX_SIZE)

#define MAKE_LOGGER_FMT(lvl)                                                   \
  inline void lvl##f(char const * fmt, ...) { VA_LOG(level::lvl); }            \
  inline void lvl##nf(size_t n, char const * fmt, ...) {                       \
    VA_LOGN(level::lvl, n);                                                    \
  }                                                                            \
  inline void lvl(char const * msg) { log(level::lvl, msg); }                  \
  inline void lvl(std::string const & msg) { log(level::lvl, msg); }

namespace logging {
  enum class level : int;
  class logger_impl;

  /**
   * A simple logger interface that is used for performing C-Style logging a la
   * printf()/nprintf().
   * TODO: Add the option to provide location_info with the log_here macro
   * Unlink the logging::logger class, this class only provides access to its
   * logging methods through functions like warn(), error(), fatal(), etc.
   * Each of these functions corresponds to a logging::level enum, and
   * constructs its message by calling vsnprintf() under the hood.
   * Overrides for no formatting, std::string inputs, and explicitly sizing the
   * storage buffer are made available with the following function names e.g.:
   * error("This is a string")              -> logs "This is a string"
   * error(std::string("This is a string")) -> logs "This is a string"
   * errorf("This is a %s", "string")       -> logs "This is a string"
   * errornf(14, "This is a %s", "string")  -> logs "This is a str"
   */
  class c_logger {
  private:
    friend class manager;
    std::string logger_name_;
    std::shared_ptr<logger_impl> impl_;

  public:
    static const size_t LOGF_MAX_SIZE = 2048;

  public:
    MAKE_LOGGER_FMT(trace)
    MAKE_LOGGER_FMT(debug)
    MAKE_LOGGER_FMT(info)
    MAKE_LOGGER_FMT(warn)
    MAKE_LOGGER_FMT(error)
    MAKE_LOGGER_FMT(critical)
    MAKE_LOGGER_FMT(fatal)

    void flush();

    ~c_logger();

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

  private:
    void vlognf(level, size_t, char const *, va_list);
    void log(level, std::string const &);
  };
}
#undef VA_LOG
#undef LA_LOGN