chore: optimize DomainTrie for only one child

component/trie/domain.go

@@ -119,8 +119,8 @@ func (t *DomainTrie[T]) search(node *Node[T], parts []string) *Node[T] {
 	return node.getChild(dotWildcard)
 }
 
-func (t *DomainTrie[T]) FinishInsert() {
-	t.root.finishAdd()
+func (t *DomainTrie[T]) Optimize() {
+	t.root.optimize()
 }
 
 // New returns a new, empty Trie.

component/trie/node.go

@@ -4,6 +4,8 @@ import "strings"
 
 // Node is the trie's node
 type Node[T any] struct {
+	childNode *Node[T] // optimize for only one child
+	childStr  string
 	children  map[string]*Node[T]
 	inited    bool
 	data      T
@@ -11,6 +13,9 @@ type Node[T any] struct {
 
 func (n *Node[T]) getChild(s string) *Node[T] {
 	if n.children == nil {
+		if n.childNode != nil && n.childStr == s {
+			return n.childNode
+		}
 		return nil
 	}
 	return n.children[s]
@@ -22,8 +27,19 @@ func (n *Node[T]) hasChild(s string) bool {
 
 func (n *Node[T]) addChild(s string, child *Node[T]) {
 	if n.children == nil {
-		n.children = map[string]*Node[T]{}
+		if n.childNode == nil {
+			n.childStr = s
+			n.childNode = child
+			return
 		}
+		n.children = map[string]*Node[T]{}
+		if n.childNode != nil {
+			n.children[n.childStr] = n.childNode
+		}
+		n.childStr = ""
+		n.childNode = nil
+	}
+
 	n.children[s] = child
 }
 
@@ -36,12 +52,28 @@ func (n *Node[T]) getOrNewChild(s string) *Node[T] {
 	return node
 }
 
-func (n *Node[T]) finishAdd() {
+func (n *Node[T]) optimize() {
+	if len(n.childStr) > 0 {
+		n.childStr = strings.Clone(n.childStr)
+	}
+	if n.childNode != nil {
+		n.childNode.optimize()
+	}
 	if n.children == nil {
 		return
 	}
-	if len(n.children) == 0 {
+	switch len(n.children) {
+	case 0:
 		n.children = nil
+		return
+	case 1:
+		for key := range n.children {
+			n.childStr = key
+			n.childNode = n.children[key]
+		}
+		n.children = nil
+		n.optimize()
+		return
 	}
 	children := make(map[string]*Node[T], len(n.children)) // avoid map reallocate memory
 	for key := range n.children {
@@ -58,7 +90,7 @@ func (n *Node[T]) finishAdd() {
 			key = strings.Clone(key)
 		}
 		children[key] = child
-		child.finishAdd()
+		child.optimize()
 	}
 	n.children = children
 }
@@ -80,8 +112,5 @@ func (n *Node[T]) Data() T {
 }
 
 func newNode[T any]() *Node[T] {
-	return &Node[T]{
-		children: nil,
-		inited:   false,
-	}
+	return &Node[T]{}
 }

config/config.go

@@ -972,7 +972,7 @@ func parseHosts(cfg *RawConfig) (*trie.DomainTrie[netip.Addr], error) {
 			_ = tree.Insert(domain, ip)
 		}
 	}
-	tree.FinishInsert()
+	tree.Optimize()
 
 	return tree, nil
 }
@@ -1207,7 +1207,7 @@ func parseDNS(rawCfg *RawConfig, hosts *trie.DomainTrie[netip.Addr], rules []C.R
 			for _, domain := range cfg.FakeIPFilter {
 				_ = host.Insert(domain, struct{}{})
 			}
-			host.FinishInsert()
+			host.Optimize()
 		}
 
 		if len(dnsCfg.Fallback) != 0 {
@@ -1220,7 +1220,7 @@ func parseDNS(rawCfg *RawConfig, hosts *trie.DomainTrie[netip.Addr], rules []C.R
 				}
 				_ = host.Insert(fb.Addr, struct{}{})
 			}
-			host.FinishInsert()
+			host.Optimize()
 		}
 
 		pool, err := fakeip.New(fakeip.Options{
@@ -1396,7 +1396,7 @@ func parseSniffer(snifferRaw RawSniffer) (*Sniffer, error) {
 			return nil, fmt.Errorf("error domian[%s] in force-domain, error:%v", domain, err)
 		}
 	}
-	sniffer.ForceDomain.FinishInsert()
+	sniffer.ForceDomain.Optimize()
 
 	sniffer.SkipDomain = trie.New[struct{}]()
 	for _, domain := range snifferRaw.SkipDomain {
@@ -1405,7 +1405,7 @@ func parseSniffer(snifferRaw RawSniffer) (*Sniffer, error) {
 			return nil, fmt.Errorf("error domian[%s] in force-domain, error:%v", domain, err)
 		}
 	}
-	sniffer.SkipDomain.FinishInsert()
+	sniffer.SkipDomain.Optimize()
 
 	return sniffer, nil
 }

dns/filters.go

@@ -79,7 +79,7 @@ func NewDomainFilter(domains []string) *domainFilter {
 	for _, domain := range domains {
 		_ = df.tree.Insert(domain, struct{}{})
 	}
-	df.tree.FinishInsert()
+	df.tree.Optimize()
 	return &df
 }
 

dns/resolver.go

@@ -435,7 +435,7 @@ func NewResolver(config Config) *Resolver {
 		for domain, nameserver := range config.Policy {
 			_ = r.policy.Insert(domain, NewPolicy(transform([]NameServer{nameserver}, defaultResolver)))
 		}
-		r.policy.FinishInsert()
+		r.policy.Optimize()
 	}
 
 	fallbackIPFilters := []fallbackIPFilter{}

rules/provider/domain_strategy.go

@@ -36,7 +36,7 @@ func (d *domainStrategy) OnUpdate(rules []string) {
 			count++
 		}
 	}
-	domainTrie.FinishInsert()
+	domainTrie.Optimize()
 
 	d.domainRules = domainTrie
 	d.count = count