logger.hpp

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/* Copyright (c) 2023 Otto Link. Distributed under the terms of the GNU General
   Public License. The full license is in the file LICENSE, distributed with
   this software. */
 
#pragma once
 
#include <iostream>
#include <string>
#include <string_view>
 
#include <concepts>
#include <format>
#include <source_location>
 
#ifndef HIGHMAP_ENABLE_LOGS
#define HIGHMAP_ENABLE_LOGS 1
#endif
 
#ifndef HIGHMAP_LOG_LEVEL_WIDTH
#define HIGHMAP_LOG_LEVEL_WIDTH 5
#endif
 
#ifndef HIGHMAP_LOG_FILE_WIDTH
#define HIGHMAP_LOG_FILE_WIDTH 24
#endif
 
namespace hmap::log
{
 
#if !HIGHMAP_ENABLE_LOGS
 
template <typename... Args> inline void trace([[maybe_unused]] Args &&...args)
{
}
 
template <typename... Args> inline void info([[maybe_unused]] Args &&...args)
{
}
 
template <typename... Args> inline void warn([[maybe_unused]] Args &&...args)
{
}
 
template <typename... Args> inline void error([[maybe_unused]] Args &&...args)
{
}
 
#else
 
template <typename... Args> struct format_string_with_loc
{
  std::format_string<Args...> fmt;
  std::source_location        loc;
 
  template <typename S>
    requires std::constructible_from<std::format_string<Args...>, const S &>
  consteval format_string_with_loc(
      const S                    &s,
      const std::source_location &l = std::source_location::current())
      : fmt(s), loc(l)
  {
  }
};
 
namespace detail
{
 
enum class Level
{
  Trace,
  Info,
  Warn,
  Error
};
 
inline const char *level_to_string(Level level)
{
  switch (level)
  {
  case Level::Trace: return "trace";
  case Level::Info: return "info";
  case Level::Warn: return "warn";
  case Level::Error: return "error";
  }
  return "info";
}
 
constexpr std::string_view get_filename(std::string_view path)
{
  const size_t pos = path.find_last_of("/\\");
  return (pos == std::string_view::npos) ? path : path.substr(pos + 1);
}
 
inline std::string format_fixed_width(std::string_view str, size_t width)
{
  if (width == 0) return std::string(str);
  if (str.length() > width)
  {
    if (width <= 3) return std::string(str.substr(0, width));
    return std::string(str.substr(0, width - 3)) + "...";
  }
  std::string res(str);
  res.append(width - str.length(), ' ');
  return res;
}
 
inline void log_impl(Level                       level,
                     std::string_view            msg,
                     const std::source_location &loc)
{
  std::ostream &out = (level == Level::Warn || level == Level::Error)
                          ? std::cerr
                          : std::cout;
  out << "hmap " << "["
      << format_fixed_width(level_to_string(level), HIGHMAP_LOG_LEVEL_WIDTH)
      << "] ["
      << format_fixed_width(get_filename(loc.file_name()),
                            HIGHMAP_LOG_FILE_WIDTH)
      << ":" << loc.line() << "] " << msg << std::endl;
}
 
} // namespace detail
 
// -----------------------------------------------------------------------------
// trace
// -----------------------------------------------------------------------------
 
template <typename... Args>
inline void trace(format_string_with_loc<std::type_identity_t<Args>...> fl,
                  Args &&...args)
{
  std::string msg = std::vformat(fl.fmt.get(), std::make_format_args(args...));
  detail::log_impl(detail::Level::Trace, msg, fl.loc);
}
 
inline void trace(
    std::string_view            message,
    const std::source_location &loc = std::source_location::current())
{
  detail::log_impl(detail::Level::Trace, message, loc);
}
 
template <typename... Args>
inline void trace(const std::source_location &loc,
                  std::format_string<Args...> fmt,
                  Args &&...args)
{
  std::string msg = std::vformat(fmt.get(), std::make_format_args(args...));
  detail::log_impl(detail::Level::Trace, msg, loc);
}
 
inline void trace(const std::source_location &loc, std::string_view message)
{
  detail::log_impl(detail::Level::Trace, message, loc);
}
 
// -----------------------------------------------------------------------------
// info
// -----------------------------------------------------------------------------
 
template <typename... Args>
inline void info(format_string_with_loc<std::type_identity_t<Args>...> fl,
                 Args &&...args)
{
  std::string msg = std::vformat(fl.fmt.get(), std::make_format_args(args...));
  detail::log_impl(detail::Level::Info, msg, fl.loc);
}
 
inline void info(
    std::string_view            message,
    const std::source_location &loc = std::source_location::current())
{
  detail::log_impl(detail::Level::Info, message, loc);
}
 
template <typename... Args>
inline void info(const std::source_location &loc,
                 std::format_string<Args...> fmt,
                 Args &&...args)
{
  std::string msg = std::vformat(fmt.get(), std::make_format_args(args...));
  detail::log_impl(detail::Level::Info, msg, loc);
}
 
inline void info(const std::source_location &loc, std::string_view message)
{
  detail::log_impl(detail::Level::Info, message, loc);
}
 
// -----------------------------------------------------------------------------
// warn
// -----------------------------------------------------------------------------
 
template <typename... Args>
inline void warn(format_string_with_loc<std::type_identity_t<Args>...> fl,
                 Args &&...args)
{
  std::string msg = std::vformat(fl.fmt.get(), std::make_format_args(args...));
  detail::log_impl(detail::Level::Warn, msg, fl.loc);
}
 
inline void warn(
    std::string_view            message,
    const std::source_location &loc = std::source_location::current())
{
  detail::log_impl(detail::Level::Warn, message, loc);
}
 
template <typename... Args>
inline void warn(const std::source_location &loc,
                 std::format_string<Args...> fmt,
                 Args &&...args)
{
  std::string msg = std::vformat(fmt.get(), std::make_format_args(args...));
  detail::log_impl(detail::Level::Warn, msg, loc);
}
 
inline void warn(const std::source_location &loc, std::string_view message)
{
  detail::log_impl(detail::Level::Warn, message, loc);
}
 
// -----------------------------------------------------------------------------
// error
// -----------------------------------------------------------------------------
 
template <typename... Args>
inline void error(format_string_with_loc<std::type_identity_t<Args>...> fl,
                  Args &&...args)
{
  std::string msg = std::vformat(fl.fmt.get(), std::make_format_args(args...));
  detail::log_impl(detail::Level::Error, msg, fl.loc);
}
 
inline void error(
    std::string_view            message,
    const std::source_location &loc = std::source_location::current())
{
  detail::log_impl(detail::Level::Error, message, loc);
}
 
template <typename... Args>
inline void error(const std::source_location &loc,
                  std::format_string<Args...> fmt,
                  Args &&...args)
{
  std::string msg = std::vformat(fmt.get(), std::make_format_args(args...));
  detail::log_impl(detail::Level::Error, msg, loc);
}
 
inline void error(const std::source_location &loc, std::string_view message)
{
  detail::log_impl(detail::Level::Error, message, loc);
}
 
#endif
 
} // namespace hmap::log