improve performance of domain matcher

common/strmatcher/domain_matcher.go

@@ -0,0 +1,52 @@
+package strmatcher
+
+import "strings"
+
+func breakDomain(domain string) []string {
+	return strings.Split(domain, ".")
+}
+
+type node struct {
+	value uint32
+	sub   map[string]*node
+}
+
+type DomainMatcherGroup struct {
+	root *node
+}
+
+func (g *DomainMatcherGroup) Add(domain string, value uint32) {
+	if g.root == nil {
+		g.root = &node{
+			sub: make(map[string]*node),
+		}
+	}
+
+	current := g.root
+	parts := breakDomain(domain)
+	for i := len(parts) - 1; i >= 0; i-- {
+		part := parts[i]
+		next := current.sub[part]
+		if next == nil {
+			next = &node{sub: make(map[string]*node)}
+			current.sub[part] = next
+		}
+		current = next
+	}
+
+	current.value = value
+}
+
+func (g *DomainMatcherGroup) Match(domain string) uint32 {
+	current := g.root
+	parts := breakDomain(domain)
+	for i := len(parts) - 1; i >= 0; i-- {
+		part := parts[i]
+		next := current.sub[part]
+		if next == nil {
+			break
+		}
+		current = next
+	}
+	return current.value
+}