// even though it only considers text until the first non-comment
// for +build lines.
//
// getFileInfo will return errNonSource if the file is not a source or object
// file and shouldn't even be added to IgnoredFiles.
func getFileInfo(dir, name string, fset *token.FileSet) (*fileInfo, error) {
	if strings.HasPrefix(name, "_") ||
		strings.HasPrefix(name, ".") {
		return nil, nil
	}

	i := strings.LastIndex(name, ".")