chore: decrease DomainTrie's memory use

component/trie/domain.go

@@ -73,11 +73,7 @@ func (t *DomainTrie[T]) insert(parts []string, data T) {
 	// reverse storage domain part to save space
 	for i := len(parts) - 1; i >= 0; i-- {
 		part := parts[i]
-		if !node.hasChild(part) {
-			node.addChild(part, newNode[T]())
-		}
-
-		node = node.getChild(part)
+		node = node.getOrNewChild(part)
 	}
 
 	node.setData(data)
@@ -123,6 +119,10 @@ func (t *DomainTrie[T]) search(node *Node[T], parts []string) *Node[T] {
 	return node.getChild(dotWildcard)
 }
 
+func (t *DomainTrie[T]) FinishInsert() {
+	t.root.finishAdd()
+}
+
 // New returns a new, empty Trie.
 func New[T any]() *DomainTrie[T] {
 	return &DomainTrie[T]{root: newNode[T]()}

component/trie/node.go

@@ -1,5 +1,7 @@
 package trie
 
+import "strings"
+
 // Node is the trie's node
 type Node[T any] struct {
 	children map[string]*Node[T]
@@ -8,6 +10,9 @@ type Node[T any] struct {
 }
 
 func (n *Node[T]) getChild(s string) *Node[T] {
+	if n.children == nil {
+		return nil
+	}
 	return n.children[s]
 }
 
@@ -16,9 +21,48 @@ 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]{}
+	}
 	n.children[s] = child
 }
 
+func (n *Node[T]) getOrNewChild(s string) *Node[T] {
+	node := n.getChild(s)
+	if node == nil {
+		node = newNode[T]()
+		n.addChild(s, node)
+	}
+	return node
+}
+
+func (n *Node[T]) finishAdd() {
+	if n.children == nil {
+		return
+	}
+	if len(n.children) == 0 {
+		n.children = nil
+	}
+	children := make(map[string]*Node[T], len(n.children)) // avoid map reallocate memory
+	for key := range n.children {
+		child := n.children[key]
+		if child == nil {
+			continue
+		}
+		switch key { // try to save string's memory
+		case wildcard:
+			key = wildcard
+		case dotWildcard:
+			key = dotWildcard
+		default:
+			key = strings.Clone(key)
+		}
+		children[key] = child
+		child.finishAdd()
+	}
+	n.children = children
+}
+
 func (n *Node[T]) isEmpty() bool {
 	if n == nil || n.inited == false {
 		return true
@@ -37,13 +81,7 @@ func (n *Node[T]) Data() T {
 
 func newNode[T any]() *Node[T] {
 	return &Node[T]{
-		children: map[string]*Node[T]{},
+		children: nil,
 		inited:   false,
-		data:     getZero[T](),
 	}
 }
-
-func getZero[T any]() T {
-	var result T
-	return result
-}