class DEBUGGER__::ThreadClient

def get_src(frame,
            max_lines:,
            start_line: nil,
            end_line: nil,
            dir: +1)
  if file_lines = frame.file_lines
    frame_line = frame.location.lineno - 1
    if CONFIG[:no_lineno]
      lines = file_lines
    else
      lines = file_lines.map.with_index do |e, i|
        cur = i == frame_line ? '=>' : '  '
        line = colorize_dim('%4d|' % (i+1))
        "#{cur}#{line} #{e}"
      end
    end
    unless start_line
      if frame.show_line
        if dir > 0
          start_line = frame.show_line
        else
          end_line = frame.show_line - max_lines
          start_line = [end_line - max_lines, 0].max
        end
      else
        start_line = [frame_line - max_lines/2, 0].max
      end
    end
    unless end_line
      end_line = [start_line + max_lines, lines.size].min
    end
    if start_line != end_line && max_lines
      [start_line, end_line, lines]
    end
  else # no file lines
    nil
  end
rescue Exception => e
  p e
  pp e.backtrace
  exit!
end