From fb628e9c62d2576aff3643d4ff30610a0a92c76f Mon Sep 17 00:00:00 2001
From: Dreamacro <305009791@qq.com>
Date: Sun, 7 Jun 2020 17:25:51 +0800
Subject: [PATCH] Feature: add default hosts `localhost`

---
 component/trie/domain.go      | 6 +++++-
 component/trie/domain_test.go | 3 +++
 config/config.go              | 6 ++++++
 3 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/component/trie/domain.go b/component/trie/domain.go
index 5dc60553..e8dcf213 100644
--- a/component/trie/domain.go
+++ b/component/trie/domain.go
@@ -30,7 +30,11 @@ func validAndSplitDomain(domain string) ([]string, bool) {
 
 	parts := strings.Split(domain, domainStep)
 	if len(parts) == 1 {
-		return nil, false
+		if parts[0] == "" {
+			return nil, false
+		}
+
+		return parts, true
 	}
 
 	for _, part := range parts[1:] {
diff --git a/component/trie/domain_test.go b/component/trie/domain_test.go
index ded5282b..38b347e1 100644
--- a/component/trie/domain_test.go
+++ b/component/trie/domain_test.go
@@ -14,6 +14,7 @@ func TestTrie_Basic(t *testing.T) {
 	domains := []string{
 		"example.com",
 		"google.com",
+		"localhost",
 	}
 
 	for _, domain := range domains {
@@ -24,6 +25,8 @@ func TestTrie_Basic(t *testing.T) {
 	assert.NotNil(t, node)
 	assert.True(t, node.Data.(net.IP).Equal(localIP))
 	assert.NotNil(t, tree.Insert("", localIP))
+	assert.Nil(t, tree.Search(""))
+	assert.NotNil(t, tree.Search("localhost"))
 }
 
 func TestTrie_Wildcard(t *testing.T) {
diff --git a/config/config.go b/config/config.go
index f1562bc2..f18d0369 100644
--- a/config/config.go
+++ b/config/config.go
@@ -418,6 +418,12 @@ func parseRules(cfg *RawConfig, proxies map[string]C.Proxy) ([]C.Rule, error) {
 
 func parseHosts(cfg *RawConfig) (*trie.DomainTrie, error) {
 	tree := trie.New()
+
+	// add default hosts
+	if err := tree.Insert("localhost", net.IP{127, 0, 0, 1}); err != nil {
+		println(err.Error())
+	}
+
 	if len(cfg.Hosts) != 0 {
 		for domain, ipStr := range cfg.Hosts {
 			ip := net.ParseIP(ipStr)