class MonoLogger::LocklessLogDevice

def add_log_header(file)
  file.write(
    "# Logfile created on %s by %s\n" % [Time.now.to_s, Logger::ProgName]
  )
end

def close
  @dev.close rescue nil
end

def create_logfile(filename)
  logdev = open(filename, (File::WRONLY | File::APPEND | File::CREAT))
  logdev.sync = true
  add_log_header(logdev)
  logdev
end

def initialize(log = nil)
  @dev = @filename = @shift_age = @shift_size = nil
  if log.respond_to?(:write) and log.respond_to?(:close)
    @dev = log
  else
    @dev = open_logfile(log)
    @dev.sync = true
    @filename = log
  end
end

def open_logfile(filename)
  if (FileTest.exist?(filename))
    open(filename, (File::WRONLY | File::APPEND))
  else
    create_logfile(filename)
  end
end

def write(message)
  @dev.write(message)
rescue Exception => ignored
  warn("log writing failed. #{ignored}")
end