[ruby] Logger: Use filepath if progname was omitted.

ext_logger.rb

# encoding: utf-8

require 'pathname'

# Set filename if progname was omitted.
class Logger
  alias_method :org_add, :add
  def add(severity, message = nil, progname = nil, &block)
    if message.nil? && !block_given?
      message = progname
      path = Pathname.new(caller(2).first[/^(.+):\d+:in /, 1])
      if path.absolute?
        path = path.relative_path_from(Pathname.getwd.expand_path)
      end
      progname = path.to_s
    end
    org_add(severity, message, progname, &block)
  end
end