tree: sync part httprouter codes and reduce if/else (#2163)

tree.go

@@ -62,6 +62,15 @@ func min(a, b int) int {
 	return b
 }
 
+func longestCommonPrefix(a, b string) int {
+	i := 0
+	max := min(len(a), len(b))
+	for i < max && a[i] == b[i] {
+		i++
+	}
+	return i
+}
+
 func countParams(path string) uint8 {
 	var n uint
 	for i := 0; i < len(path); i++ {
@@ -127,11 +136,16 @@ func (n *node) addRoute(path string, handlers HandlersChain) {
 	n.priority++
 	numParams := countParams(path)
 
+	// Empty tree
+	if len(n.path) == 0 && len(n.children) == 0 {
+		n.insertChild(numParams, path, fullPath, handlers)
+		n.nType = root
+		return
+	}
+
 	parentFullPathIndex := 0
 
-	// non-empty tree
+walk:
-	if len(n.path) > 0 || len(n.children) > 0 {
-	walk:
 	for {
 		// Update maxParams of the current node
 		if numParams > n.maxParams {
@@ -141,11 +155,7 @@ func (n *node) addRoute(path string, handlers HandlersChain) {
 		// Find the longest common prefix.
 		// This also implies that the common prefix contains no ':' or '*'
 		// since the existing key can't contain those chars.
-			i := 0
+		i := longestCommonPrefix(path, n.path)
-			max := min(len(path), len(n.path))
-			for i < max && path[i] == n.path[i] {
-				i++
-			}
 
 		// Split edge
 		if i < len(n.path) {
@@ -253,10 +263,6 @@ func (n *node) addRoute(path string, handlers HandlersChain) {
 		}
 		return
 	}
-	} else { // Empty tree
-		n.insertChild(numParams, path, fullPath, handlers)
-		n.nType = root
-	}
 }
 
 func (n *node) insertChild(numParams uint8, path string, fullPath string, handlers HandlersChain) {
@@ -542,7 +548,30 @@ func (n *node) findCaseInsensitivePath(path string, fixTrailingSlash bool) (ciPa
 		path = path[len(n.path):]
 		ciPath = append(ciPath, n.path...)
 
-		if len(path) > 0 {
+		if len(path) == 0 {
+			// We should have reached the node containing the handle.
+			// Check if this node has a handle registered.
+			if n.handlers != nil {
+				return ciPath, true
+			}
+
+			// No handle found.
+			// Try to fix the path by adding a trailing slash
+			if fixTrailingSlash {
+				for i := 0; i < len(n.indices); i++ {
+					if n.indices[i] == '/' {
+						n = n.children[i]
+						if (len(n.path) == 1 && n.handlers != nil) ||
+							(n.nType == catchAll && n.children[0].handlers != nil) {
+							return append(ciPath, '/'), true
+						}
+						return
+					}
+				}
+			}
+			return
+		}
+
 		// If this node does not have a wildcard (param or catchAll) child,
 		// we can just look up the next child node and continue to walk down
 		// the tree
@@ -610,29 +639,6 @@ func (n *node) findCaseInsensitivePath(path string, fixTrailingSlash bool) (ciPa
 		default:
 			panic("invalid node type")
 		}
-		} else {
-			// We should have reached the node containing the handle.
-			// Check if this node has a handle registered.
-			if n.handlers != nil {
-				return ciPath, true
-			}
-
-			// No handle found.
-			// Try to fix the path by adding a trailing slash
-			if fixTrailingSlash {
-				for i := 0; i < len(n.indices); i++ {
-					if n.indices[i] == '/' {
-						n = n.children[i]
-						if (len(n.path) == 1 && n.handlers != nil) ||
-							(n.nType == catchAll && n.children[0].handlers != nil) {
-							return append(ciPath, '/'), true
-						}
-						return
-					}
-				}
-			}
-			return
-		}
 	}
 
 	// Nothing found.