From 6290e4ad9a3f4c1101b49c90736d7f7e617ea1bf Mon Sep 17 00:00:00 2001
From: djcb <djcb@djcbsoftware.nl>
Date: Fri, 18 May 2018 15:55:40 +0300
Subject: [PATCH] query-parser: special-case wildcards

We were transforming wild-card searches into regular-expression
searches; while that works, it's also significantly slower.

So, instead, special-case wildcards, and use the Xapian machinery for
wildcard queries.
---
 lib/parser/parser.cc |  9 ++-------
 lib/parser/xapian.cc | 16 ++++++++++++++--
 2 files changed, 16 insertions(+), 9 deletions(-)

diff --git a/lib/parser/parser.cc b/lib/parser/parser.cc
index 253825f6..72ae6524 100644
--- a/lib/parser/parser.cc
+++ b/lib/parser/parser.cc
@@ -167,14 +167,9 @@ data (Mux::Tokens& tokens, ProcPtr proc, WarningVec& warnings)
 	}
 
 	// does it look like a regexp?
-	if (val.length()>=2) {
-		if (val[0]=='/' && val[val.length()-1] == '/')
+	if (val.length() >=2 )
+		if (val[0] == '/' && val[val.length()-1] == '/')
 			return regex (fields, val, token.pos, proc, warnings);
-		else if (val[val.length()-1] == '*')
-			return regex (fields, // transfrom wildcard into regexp
-				      "/" + val.substr(0, val.length()-1) + ".*/",
-				      token.pos, proc, warnings);
-	}
 
 	// does it look like a range?
 	const auto dotdot = val.find("..");
diff --git a/lib/parser/xapian.cc b/lib/parser/xapian.cc
index b95ff569..08bdebe7 100644
--- a/lib/parser/xapian.cc
+++ b/lib/parser/xapian.cc
@@ -48,18 +48,30 @@ xapian_query_op (const Mux::Tree& tree)
 	return Xapian::Query(op, childvec.begin(), childvec.end());
 }
 
+
+static Xapian::Query
+maybe_wildcard (const Value* val, const std::string& str)
+{
+	const auto vlen = str.length();
+	if (vlen <= 1 || str[vlen-1] != '*')
+		return Xapian::Query(val->prefix + str);
+	else
+		return Xapian::Query(Xapian::Query::OP_WILDCARD,
+				     val->prefix + str.substr(0, vlen-1));
+}
+
 static Xapian::Query
 xapian_query_value (const Mux::Tree& tree)
 {
 	const auto v = dynamic_cast<Value*> (tree.node.data.get());
 	if (!v->phrase)
-		return Xapian::Query(v->prefix + v->value);
+		return maybe_wildcard(v, v->value);
 
 	const auto parts = split (v->value, " ");
 
 	std::vector<Xapian::Query> phvec;
 	for (const auto p: parts)
-		phvec.push_back(Xapian::Query(v->prefix + p));
+		phvec.emplace_back(maybe_wildcard(v, p));
 
 	if (parts.empty())
 		return Xapian::Query::MatchNothing; // shouldn't happen