Gin 路由添加流程

func (engine *Engine) addRoute(method, path string, handlers HandlersChain) {	assert1(path[0] == '/', "path must begin with '/'")	assert1(method != "", "HTTP method can not be empty")	assert1(len(handlers) > 0, "there must be at least one handler")
	debugPrintRoute(method, path, handlers)
	root := engine.trees.get(method)//是否有HTTP方法的路由树	if root == nil {//没有 构建根节点		root = new(node)		root.fullPath = "/"		engine.trees = append(engine.trees, methodTree{method: method, root: root})	}	root.addRoute(path, handlers)
	// Update maxParams	if paramsCount := countParams(path); paramsCount > engine.maxParams {		engine.maxParams = paramsCount	}
	if sectionsCount := countSections(path); sectionsCount > engine.maxSections {		engine.maxSections = sectionsCount	}}

func (n *node) addRoute(path string, handlers HandlersChain) {	fullPath := path	n.priority++
	// Empty tree	if len(n.path) == 0 && len(n.children) == 0 {		n.insertChild(path, fullPath, handlers)		n.nType = root		return	}
	parentFullPathIndex := 0
walk:	for {		// 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 := longestCommonPrefix(path, n.path)
		// Split edge		if i < len(n.path) {			child := node{				path:      n.path[i:],				wildChild: n.wildChild,				indices:   n.indices,				children:  n.children,				handlers:  n.handlers,				priority:  n.priority - 1,				fullPath:  n.fullPath,			}
			n.children = []*node{&child}			// []byte for proper unicode char conversion, see #65			n.indices = bytesconv.BytesToString([]byte{n.path[i]})			n.path = path[:i]			n.handlers = nil			n.wildChild = false			n.fullPath = fullPath[:parentFullPathIndex+i]		}
		// Make new node a child of this node		if i < len(path) {			path = path[i:]			c := path[0]
			// '/' after param			if n.nType == param && c == '/' && len(n.children) == 1 {				parentFullPathIndex += len(n.path)				n = n.children[0]				n.priority++				continue walk			}
			// Check if a child with the next path byte exists			for i, max := 0, len(n.indices); i < max; i++ {				if c == n.indices[i] {					parentFullPathIndex += len(n.path)					i = n.incrementChildPrio(i)					n = n.children[i]					continue walk				}			}
			// Otherwise insert it			if c != ':' && c != '*' && n.nType != catchAll {				// []byte for proper unicode char conversion, see #65				n.indices += bytesconv.BytesToString([]byte{c})				child := &node{					fullPath: fullPath,				}				n.addChild(child)				n.incrementChildPrio(len(n.indices) - 1)				n = child			} else if n.wildChild {				// inserting a wildcard node, need to check if it conflicts with the existing wildcard				n = n.children[len(n.children)-1]				n.priority++
				// Check if the wildcard matches				if len(path) >= len(n.path) && n.path == path[:len(n.path)] &&					// Adding a child to a catchAll is not possible					n.nType != catchAll &&					// Check for longer wildcard, e.g. :name and :names					(len(n.path) >= len(path) || path[len(n.path)] == '/') {					continue walk				}
				// Wildcard conflict				pathSeg := path				if n.nType != catchAll {					pathSeg = strings.SplitN(pathSeg, "/", 2)[0]				}				prefix := fullPath[:strings.Index(fullPath, pathSeg)] + n.path				panic("'" + pathSeg +					"' in new path '" + fullPath +					"' conflicts with existing wildcard '" + n.path +					"' in existing prefix '" + prefix +					"'")			}
			n.insertChild(path, fullPath, handlers)			return		}
		// Otherwise add handle to current node		if n.handlers != nil {			panic("handlers are already registered for path '" + fullPath + "'")		}		n.handlers = handlers		n.fullPath = fullPath		return	}}