From 48e82f9ab5c337f9579737d6408047485100a53d Mon Sep 17 00:00:00 2001
From: Ainar Garipov <a.garipov@adguard.com>
Date: Mon, 29 Mar 2021 19:35:35 +0300
Subject: [PATCH] Pull request: 2479 simpl

Updates #2479.

Squashed commit of the following:

commit 0fdb0d041d0bd0d9af64513cf82397456a30e2f2
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Mon Mar 29 19:22:56 2021 +0300

    dnsfilter: add a comment

commit d5d6538b8b5133d7c1e9b242a8ac802448d40893
Merge: 6a09acc2 e710ce11
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Mon Mar 29 19:19:39 2021 +0300

    Merge branch 'master' into 2479-simpl

commit 6a09acc2626900fc52873fb0bba3c5978ae319a0
Author: jvoisin <julien.voisin@dustri.org>
Date:   Tue Dec 22 16:43:47 2020 +0100

    Generalise a construct to simplify a function
---
 internal/dnsfilter/rewrites.go | 24 +++++++++++++++---------
 1 file changed, 15 insertions(+), 9 deletions(-)

diff --git a/internal/dnsfilter/rewrites.go b/internal/dnsfilter/rewrites.go
index 146be60a..5aae925a 100644
--- a/internal/dnsfilter/rewrites.go
+++ b/internal/dnsfilter/rewrites.go
@@ -122,21 +122,27 @@ func findRewrites(a []RewriteEntry, host string) []RewriteEntry {
 
 	sort.Sort(rr)
 
-	isWC := isWildcard(rr[0].Domain)
-	if !isWC {
-		for i, r := range rr {
-			if isWildcard(r.Domain) {
-				rr = rr[:i]
-				break
-			}
+	for i, r := range rr {
+		if isWildcard(r.Domain) {
+			// Don't use rr[:0], because we need to return at least
+			// one item here.
+			rr = rr[:max(1, i)]
+
+			break
 		}
-	} else {
-		rr = rr[:1]
 	}
 
 	return rr
 }
 
+func max(a, b int) int {
+	if a > b {
+		return a
+	}
+
+	return b
+}
+
 func rewriteArrayDup(a []RewriteEntry) []RewriteEntry {
 	a2 := make([]RewriteEntry, len(a))
 	copy(a2, a)