lib: improve xapianizer / xapian_term

lib/message/mu-fields.cc

@@ -79,17 +79,15 @@ Mu::field_is_combi(const std::string& name)
 std::string
 Field::xapian_term(const std::string& s) const
 {
-	const auto start{std::string(1U, xapian_prefix())};
+	auto res{std::string(1U, xapian_prefix())};
-	if (const auto& size = s.size(); size == 0)
+	if (s.empty())
-		return start;
+		return res;
 
-	std::string res{start};
 	res.reserve(s.size() + 10);
-
 	/* slightly optimized common pure-ascii. */
 	if (G_LIKELY(g_str_is_ascii(s.c_str()))) {
 		res += s;
-		for (auto i = 1; res[i]; ++i)
+		for (auto i = 1U; i != res.length(); ++i)
 			res[i] = g_ascii_tolower(res[i]);
 	} else
 		res += utf8_flatten(s);

lib/mu-query-xapianizer.cc

@@ -109,17 +109,18 @@ phrase(const Field& field, Sexp&& s)
 static Result<Xapian::Query>
 regex(const Store& store, const Field& field, const std::string& rx_str)
 {
-	auto&& str{utf8_flatten(rx_str)};
+	const auto str{utf8_flatten(rx_str)};
-	auto&& rx{Regex::make(str, G_REGEX_OPTIMIZE)};
+	const auto rx{Regex::make(str, G_REGEX_OPTIMIZE)};
 	if (!rx) {
 		mu_warning("invalid regexp: '{}': {}", str, rx.error().what());
 		return Xapian::Query::MatchNothing;
 	}
 
 	std::vector<Xapian::Query> rxvec;
-	store.for_each_term(field.id, [&](auto&& str) {
+	store.for_each_term(field.id, [&](const auto& term) {
-		if (auto&& val{str.data() + 1}; rx->matches(val))
+		std::string val{term.data() + 1};
-			rxvec.emplace_back(field.xapian_term(std::string_view{val}));
+		if (rx->matches(val))
+			rxvec.emplace_back(field.xapian_term(val));
 		return true;
 	});