class RuboCop::Cop::Lint::ScriptPermission

def executable?(processed_source)
  # Returns true if stat is executable or if the operating system
  # doesn't distinguish executable files from nonexecutable files.
  # See at: https://github.com/ruby/ruby/blob/ruby_2_4/file.c#L5362
  File.stat(processed_source.buffer.name).executable?
end

def format_message_from(processed_source)
  basename = File.basename(processed_source.buffer.name)
  format(MSG, basename)
end

def investigate(processed_source)
  return if Platform.windows?
  return unless start_with_shebang?(processed_source)
  return if executable?(processed_source)
  comment = processed_source.comments[0]
  message = format_message_from(processed_source)
  add_offense(comment, :expression, message)
end

def start_with_shebang?(processed_source)
  return false if processed_source[0].nil?
  processed_source[0].start_with?(SHEBANG)
end