Pull request: querylog: more opt

Updates 1273.

Squashed commit of the following:

commit 167c0b5acaab8a2676de2cea556c861dc0efbc72
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Mon Apr 12 18:12:43 2021 +0300

    querylog: imp naming

commit 5010ad113e46335011a721cbcc9fc9b1fc623722
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Mon Apr 12 17:53:41 2021 +0300

    querylog: more opt

internal/querylog/search.go

@@ -171,6 +171,7 @@ func (l *queryLog) searchFiles(
 	for total < params.maxFileScanEntries || params.maxFileScanEntries <= 0 {
 		var e *logEntry
 		var ts int64
+
 		e, ts, err = l.readNextEntry(r, params, cache)
 		if err != nil {
 			if err == io.EOF {
@@ -198,6 +199,29 @@ func (l *queryLog) searchFiles(
 	return entries, oldest, total
 }
 
+// quickMatchClientFinder is a wrapper around the usual client finding function
+// to make it easier to use with quick matches.
+type quickMatchClientFinder struct {
+	client func(clientID, ip string, cache clientCache) (c *Client, err error)
+	cache  clientCache
+}
+
+// findClient is a method that can be used as a quickMatchClientFinder.
+func (f quickMatchClientFinder) findClient(clientID, ip string) (c *Client) {
+	var err error
+	c, err = f.client(clientID, ip, f.cache)
+	if err != nil {
+		log.Error("querylog: enriching file record for quick search:"+
+			" for client %q (client id %q): %s",
+			ip,
+			clientID,
+			err,
+		)
+	}
+
+	return c
+}
+
 // readNextEntry reads the next log entry and checks if it matches the search
 // criteria.  It optionally uses the client cache, if provided.  e is nil if the
 // entry doesn't match the search criteria.  ts is the timestamp of the
@@ -213,6 +237,17 @@ func (l *queryLog) readNextEntry(
 		return nil, 0, err
 	}
 
+	clientFinder := quickMatchClientFinder{
+		client: l.client,
+		cache:  cache,
+	}
+
+	if !params.quickMatch(line, clientFinder.findClient) {
+		ts = readQLogTimestamp(line)
+
+		return nil, ts, nil
+	}
+
 	e = &logEntry{}
 	decodeLogEntry(e, line)