text: // Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
  // Distributed under the MIT License (http://opensource.org/licenses/MIT)
  
  #pragma once
  
  // Thread safe logger (except for set_error_handler())
  // Has name, log level, vector of std::shared sink pointers and formatter
  // Upon each log write the logger:
  // 1. Checks if its log level is enough to log the message and if yes:
  // 2. Call the underlying sinks to do the job.
  // 3. Each sink use its own private copy of a formatter to format the message
  // and send to its destination.
  //
  // The use of private formatter per sink provides the opportunity to cache some
  // formatted data, and support for different format per sink.
  
  #include <spdlog/common.h>
  #include <spdlog/details/log_msg.h>
  #include <spdlog/details/backtracer.h>
  
  #ifdef SPDLOG_WCHAR_TO_UTF8_SUPPORT
  #    ifndef _WIN32
  #        error SPDLOG_WCHAR_TO_UTF8_SUPPORT only supported on windows
  #    endif
  #    include <spdlog/details/os.h>
  #endif
  
  #include <vector>
  
  #ifndef SPDLOG_NO_EXCEPTIONS
  #    define SPDLOG_LOGGER_CATCH()                                                                                                          \
          catch (const std::exception &ex)                                                                                                   \
          {                                                                                                                                  \
              err_handler_(ex.what());                                                                                                       \
          }                                                                                                                                  \
          catch (...)                                                                                                                        \
          {                                                                                                                                  \
              err_handler_("Rethrowing unknown exception in logger");                                                                        \
              throw;                                                                                                                         \
          }
  #else
  #    define SPDLOG_LOGGER_CATCH()
  #endif
  
  namespace spdlog {
  
  class SPDLOG_API logger
  {
  public:
      // Empty logger
      explicit logger(std::string name)
          : name_(std::move(name))
          , sinks_()
      {}
  
      // Logger with range on sinks
      template<typename It>
      logger(std::string name, It begin, It end)
          : name_(std::move(name))
          , sinks_(begin, end)
      {}
  
      // Logger with single sink
      logger(std::string name, sink_ptr single_sink)
          : logger(std::move(name), {std::move(single_sink)})
      {}
  
      // Logger with sinks init list
      logger(std::string name, sinks_init_list sinks)
          : logger(std::move(name), sinks.begin(), sinks.end())
      {}
  
      virtual ~logger() = default;
  
      logger(const logger &other);
      logger(logger &&other) SPDLOG_NOEXCEPT;
      logger &operator=(logger other) SPDLOG_NOEXCEPT;
      void swap(spdlog::logger &other) SPDLOG_NOEXCEPT;
  
      template<typename FormatString, typename... Args>
      void log(source_loc loc, level::level_enum lvl, const FormatString &fmt, Args &&...args)
      {
          log_(loc, lvl, fmt, std::forward<Args>(args)...);
      }
  
      template<typename FormatString, typename... Args>
      void log(level::level_enum lvl, const FormatString &fmt, Args &&...args)
      {
          log(source_loc{}, lvl, fmt, std::forward<Args>(args)...);
      }
  
      template<typename T>
      void log(level::level_enum lvl, const T &msg)
      {
          log(source_loc{}, lvl, msg);
      }
  
      // T can be statically converted to string_view
      template<class T, typename std::enable_if<std::is_convertible<const T &, spdlog::string_view_t>::value, int>::type = 0>
      void log(source_loc loc, level::level_enum lvl, const T &msg)
      {
          log(loc, lvl, string_view_t{msg});
      }
  
      void log(log_clock::time_point log_time, source_loc loc, level::level_enum lvl, string_view_t msg)
      {
          bool log_enabled = should_log(lvl);
          bool traceback_enabled = tracer_.enabled();
          if (!log_enabled && !traceback_enabled)
          {
              return;
          }
  
          details::log_msg log_msg(log_time, loc, name_, lvl, msg);
          log_it_(log_msg, log_enabled, traceback_enabled);
      }
  
      void log(source_loc loc, level::level_enum lvl, string_view_t msg)
      {
          bool log_enabled = should_log(lvl);
          bool traceback_enabled = tracer_.enabled();
          if (!log_enabled && !traceback_enabled)
          {
              return;
          }
  
          details::log_msg log_msg(loc, name_, lvl, msg);
          log_it_(log_msg, log_enabled, traceback_enabled);
      }
  
      void log(level::level_enum lvl, string_view_t msg)
      {
          log(source_loc{}, lvl, msg);
      }
  
      // T cannot be statically converted to string_view or wstring_view
      template<class T, typename std::enable_if<!std::is_convertible<const T &, spdlog::string_view_t>::value &&
                                                    !is_convertible_to_wstring_view<const T &>::value,
                            int>::type = 0>
      void log(source_loc loc, level::level_enum lvl, const T &msg)
      {
          log(loc, lvl, "{}", msg);
      }
  
      template<typename FormatString, typename... Args>
      void trace(const FormatString &fmt, Args &&...args)
      {
          log(level::trace, fmt, std::forward<Args>(args)...);
      }
  
      template<typename FormatString, typename... Args>
      void debug(const FormatString &fmt, Args &&...args)
      {
          log(level::debug, fmt, std::forward<Args>(args)...);
      }
  
      template<typename FormatString, typename... Args>
      void info(const FormatString &fmt, Args &&...args)
      {
          log(level::info, fmt, std::forward<Args>(args)...);
      }
  
      template<typename FormatString, typename... Args>
      void warn(const FormatString &fmt, Args &&...args)
      {
          log(level::warn, fmt, std::forward<Args>(args)...);
      }
  
      template<typename FormatString, typename... Args>
      void error(const FormatString &fmt, Args &&...args)
      {
          log(level::err, fmt, std::forward<Args>(args)...);
      }
  
      template<typename FormatString, typename... Args>
      void critical(const FormatString &fmt, Args &&...args)
      {
          log(level::critical, fmt, std::forward<Args>(args)...);
      }
  
      template<typename T>
      void trace(const T &msg)
      {
          log(level::trace, msg);
      }
  
      template<typename T>
      void debug(const T &msg)
      {
          log(level::debug, msg);
      }
  
      template<typename T>
      void info(const T &msg)
      {
          log(level::info, msg);
      }
  
      template<typename T>
      void warn(const T &msg)
      {
          log(level::warn, msg);
      }
  
      template<typename T>
      void error(const T &msg)
      {
          log(level::err, msg);
      }
  
      template<typename T>
      void critical(const T &msg)
      {
          log(level::critical, msg);
      }
  
      // return true logging is enabled for the given level.
      bool should_log(level::level_enum msg_level) const
      {
          return msg_level >= level_.load(std::memory_order_relaxed);
      }
  
      // return true if backtrace logging is enabled.
      bool should_backtrace() const
      {
          return tracer_.enabled();
      }
  
      void set_level(level::level_enum log_level);
  
      level::level_enum level() const;
  
      const std::string &name() const;
  
      // set formatting for the sinks in this logger.
      // each sink will get a separate instance of the formatter object.
      void set_formatter(std::unique_ptr<formatter> f);
  
      void set_pattern(std::string pattern, pattern_time_type time_type = pattern_time_type::local);
  
      // backtrace support.
      // efficiently store all debug/trace messages in a circular buffer until needed for debugging.
      void enable_backtrace(size_t n_messages);
      void disable_backtrace();
      void dump_backtrace();
  
      // flush functions
      void flush();
      void flush_on(level::level_enum log_level);
      level::level_enum flush_level() const;
  
      // sinks
      const std::vector<sink_ptr> &sinks() const;
  
      std::vector<sink_ptr> &sinks();
  
      // error handler
      void set_error_handler(err_handler);
  
      // create new logger with same sinks and configuration.
      virtual std::shared_ptr<logger> clone(std::string logger_name);
  
  protected:
      std::string name_;
      std::vector<sink_ptr> sinks_;
      spdlog::level_t level_{level::info};
      spdlog::level_t flush_level_{level::off};
      err_handler custom_err_handler_{nullptr};
      details::backtracer tracer_;
  
      // common implementation for after templated public api has been resolved
      template<typename FormatString, typename... Args, typename Char = fmt::char_t<FormatString>,
          typename std::enable_if<!std::is_same<Char, wchar_t>::value, Char>::type * = nullptr>
      void log_(source_loc loc, level::level_enum lvl, const FormatString &fmt, Args &&...args)
      {
          bool log_enabled = should_log(lvl);
          bool traceback_enabled = tracer_.enabled();
          if (!log_enabled && !traceback_enabled)
          {
              return;
          }
          SPDLOG_TRY
          {
              memory_buf_t buf;
              fmt::detail::vformat_to(buf, fmt::to_string_view(fmt), fmt::make_format_args(args...));
              details::log_msg log_msg(loc, name_, lvl, string_view_t(buf.data(), buf.size()));
              log_it_(log_msg, log_enabled, traceback_enabled);
          }
          SPDLOG_LOGGER_CATCH()
      }
  
  #ifdef SPDLOG_WCHAR_TO_UTF8_SUPPORT
      template<typename... Args>
      void log_(source_loc loc, level::level_enum lvl, const wstring_view_t &fmt, Args &&...args)
      {
          bool log_enabled = should_log(lvl);
          bool traceback_enabled = tracer_.enabled();
          if (!log_enabled && !traceback_enabled)
          {
              return;
          }
          SPDLOG_TRY
          {
              // format to wmemory_buffer and convert to utf8
              fmt::wmemory_buffer wbuf;
              fmt::format_to(std::back_inserter(wbuf), fmt, std::forward<Args>(args)...);
              memory_buf_t buf;
              details::os::wstr_to_utf8buf(wstring_view_t(wbuf.data(), wbuf.size()), buf);
              details::log_msg log_msg(loc, name_, lvl, string_view_t(buf.data(), buf.size()));
              log_it_(log_msg, log_enabled, traceback_enabled);
          }
          SPDLOG_LOGGER_CATCH()
      }
  
      // T can be statically converted to wstring_view, and no formatting needed.
      template<class T, typename std::enable_if<std::is_convertible<const T &, spdlog::wstring_view_t>::value, int>::type = 0>
      void log_(source_loc loc, level::level_enum lvl, const T &msg)
      {
          bool log_enabled = should_log(lvl);
          bool traceback_enabled = tracer_.enabled();
          if (!log_enabled && !traceback_enabled)
          {
              return;
          }
          SPDLOG_TRY
          {
              memory_buf_t buf;
              details::os::wstr_to_utf8buf(msg, buf);
              details::log_msg log_msg(loc, name_, lvl, string_view_t(buf.data(), buf.size()));
              log_it_(log_msg, log_enabled, traceback_enabled);
          }
          SPDLOG_LOGGER_CATCH()
      }
  
  #endif // SPDLOG_WCHAR_TO_UTF8_SUPPORT
  
      // log the given message (if the given log level is high enough),
      // and save backtrace (if backtrace is enabled).
      void log_it_(const details::log_msg &log_msg, bool log_enabled, bool traceback_enabled);
      virtual void sink_it_(const details::log_msg &msg);
      virtual void flush_();
      void dump_backtrace_();
      bool should_flush_(const details::log_msg &msg);
  
      // handle errors during logging.
      // default handler prints the error to stderr at max rate of 1 message/sec.
      void err_handler_(const std::string &msg);
  };
  
  void swap(logger &a, logger &b);
  
  } // namespace spdlog
  
  #ifdef SPDLOG_HEADER_ONLY
  #    include "logger-inl.h"
  #endif
  