Function CheckPattern

validator/regex_validator.cc:34–69

namespace {

bool CheckPattern(ValidationContext& context, const NavigableAstNode& node,
                  int arg_index) {
  ABSL_DCHECK(node.expr()->has_call_expr());
  const auto& call_expr = node.expr()->call_expr();

  const Expr* pattern_expr = nullptr;

  if (call_expr.has_target()) {
    if (arg_index == 0) {
      pattern_expr = &call_expr.target();
    } else if (call_expr.args().size() > arg_index - 1) {
      pattern_expr = &call_expr.args()[arg_index - 1];
    }
  } else if (call_expr.args().size() > arg_index) {
    pattern_expr = &call_expr.args()[arg_index];
  }

  if (pattern_expr == nullptr || !pattern_expr->has_const_expr()) {
    return true;
  }

  const auto& const_expr = pattern_expr->const_expr();
  if (!const_expr.has_string_value()) {
    return true;
  }

  absl::string_view pattern_string = const_expr.string_value();
  RE2 re(pattern_string, internal::MakeRE2Options());
  if (!re.ok()) {
    context.ReportErrorAt(
        pattern_expr->id(),
        absl::StrCat("invalid regular expression: ", re.error()));
    return false;
  }
  return true;
}

}  // namespace