Upgrade chi to v5 (#17298)

vendor/github.com/go-chi/chi/v5/tree.go

@@ -0,0 +1,866 @@
+package chi
+
+// Radix tree implementation below is a based on the original work by
+// Armon Dadgar in https://github.com/armon/go-radix/blob/master/radix.go
+// (MIT licensed). It's been heavily modified for use as a HTTP routing tree.
+
+import (
+	"fmt"
+	"net/http"
+	"regexp"
+	"sort"
+	"strconv"
+	"strings"
+)
+
+type methodTyp uint
+
+const (
+	mSTUB methodTyp = 1 << iota
+	mCONNECT
+	mDELETE
+	mGET
+	mHEAD
+	mOPTIONS
+	mPATCH
+	mPOST
+	mPUT
+	mTRACE
+)
+
+var mALL = mCONNECT | mDELETE | mGET | mHEAD |
+	mOPTIONS | mPATCH | mPOST | mPUT | mTRACE
+
+var methodMap = map[string]methodTyp{
+	http.MethodConnect: mCONNECT,
+	http.MethodDelete:  mDELETE,
+	http.MethodGet:     mGET,
+	http.MethodHead:    mHEAD,
+	http.MethodOptions: mOPTIONS,
+	http.MethodPatch:   mPATCH,
+	http.MethodPost:    mPOST,
+	http.MethodPut:     mPUT,
+	http.MethodTrace:   mTRACE,
+}
+
+// RegisterMethod adds support for custom HTTP method handlers, available
+// via Router#Method and Router#MethodFunc
+func RegisterMethod(method string) {
+	if method == "" {
+		return
+	}
+	method = strings.ToUpper(method)
+	if _, ok := methodMap[method]; ok {
+		return
+	}
+	n := len(methodMap)
+	if n > strconv.IntSize-2 {
+		panic(fmt.Sprintf("chi: max number of methods reached (%d)", strconv.IntSize))
+	}
+	mt := methodTyp(2 << n)
+	methodMap[method] = mt
+	mALL |= mt
+}
+
+type nodeTyp uint8
+
+const (
+	ntStatic   nodeTyp = iota // /home
+	ntRegexp                  // /{id:[0-9]+}
+	ntParam                   // /{user}
+	ntCatchAll                // /api/v1/*
+)
+
+type node struct {
+	// subroutes on the leaf node
+	subroutes Routes
+
+	// regexp matcher for regexp nodes
+	rex *regexp.Regexp
+
+	// HTTP handler endpoints on the leaf node
+	endpoints endpoints
+
+	// prefix is the common prefix we ignore
+	prefix string
+
+	// child nodes should be stored in-order for iteration,
+	// in groups of the node type.
+	children [ntCatchAll + 1]nodes
+
+	// first byte of the child prefix
+	tail byte
+
+	// node type: static, regexp, param, catchAll
+	typ nodeTyp
+
+	// first byte of the prefix
+	label byte
+}
+
+// endpoints is a mapping of http method constants to handlers
+// for a given route.
+type endpoints map[methodTyp]*endpoint
+
+type endpoint struct {
+	// endpoint handler
+	handler http.Handler
+
+	// pattern is the routing pattern for handler nodes
+	pattern string
+
+	// parameter keys recorded on handler nodes
+	paramKeys []string
+}
+
+func (s endpoints) Value(method methodTyp) *endpoint {
+	mh, ok := s[method]
+	if !ok {
+		mh = &endpoint{}
+		s[method] = mh
+	}
+	return mh
+}
+
+func (n *node) InsertRoute(method methodTyp, pattern string, handler http.Handler) *node {
+	var parent *node
+	search := pattern
+
+	for {
+		// Handle key exhaustion
+		if len(search) == 0 {
+			// Insert or update the node's leaf handler
+			n.setEndpoint(method, handler, pattern)
+			return n
+		}
+
+		// We're going to be searching for a wild node next,
+		// in this case, we need to get the tail
+		var label = search[0]
+		var segTail byte
+		var segEndIdx int
+		var segTyp nodeTyp
+		var segRexpat string
+		if label == '{' || label == '*' {
+			segTyp, _, segRexpat, segTail, _, segEndIdx = patNextSegment(search)
+		}
+
+		var prefix string
+		if segTyp == ntRegexp {
+			prefix = segRexpat
+		}
+
+		// Look for the edge to attach to
+		parent = n
+		n = n.getEdge(segTyp, label, segTail, prefix)
+
+		// No edge, create one
+		if n == nil {
+			child := &node{label: label, tail: segTail, prefix: search}
+			hn := parent.addChild(child, search)
+			hn.setEndpoint(method, handler, pattern)
+
+			return hn
+		}
+
+		// Found an edge to match the pattern
+
+		if n.typ > ntStatic {
+			// We found a param node, trim the param from the search path and continue.
+			// This param/wild pattern segment would already be on the tree from a previous
+			// call to addChild when creating a new node.
+			search = search[segEndIdx:]
+			continue
+		}
+
+		// Static nodes fall below here.
+		// Determine longest prefix of the search key on match.
+		commonPrefix := longestPrefix(search, n.prefix)
+		if commonPrefix == len(n.prefix) {
+			// the common prefix is as long as the current node's prefix we're attempting to insert.
+			// keep the search going.
+			search = search[commonPrefix:]
+			continue
+		}
+
+		// Split the node
+		child := &node{
+			typ:    ntStatic,
+			prefix: search[:commonPrefix],
+		}
+		parent.replaceChild(search[0], segTail, child)
+
+		// Restore the existing node
+		n.label = n.prefix[commonPrefix]
+		n.prefix = n.prefix[commonPrefix:]
+		child.addChild(n, n.prefix)
+
+		// If the new key is a subset, set the method/handler on this node and finish.
+		search = search[commonPrefix:]
+		if len(search) == 0 {
+			child.setEndpoint(method, handler, pattern)
+			return child
+		}
+
+		// Create a new edge for the node
+		subchild := &node{
+			typ:    ntStatic,
+			label:  search[0],
+			prefix: search,
+		}
+		hn := child.addChild(subchild, search)
+		hn.setEndpoint(method, handler, pattern)
+		return hn
+	}
+}
+
+// addChild appends the new `child` node to the tree using the `pattern` as the trie key.
+// For a URL router like chi's, we split the static, param, regexp and wildcard segments
+// into different nodes. In addition, addChild will recursively call itself until every
+// pattern segment is added to the url pattern tree as individual nodes, depending on type.
+func (n *node) addChild(child *node, prefix string) *node {
+	search := prefix
+
+	// handler leaf node added to the tree is the child.
+	// this may be overridden later down the flow
+	hn := child
+
+	// Parse next segment
+	segTyp, _, segRexpat, segTail, segStartIdx, segEndIdx := patNextSegment(search)
+
+	// Add child depending on next up segment
+	switch segTyp {
+
+	case ntStatic:
+		// Search prefix is all static (that is, has no params in path)
+		// noop
+
+	default:
+		// Search prefix contains a param, regexp or wildcard
+
+		if segTyp == ntRegexp {
+			rex, err := regexp.Compile(segRexpat)
+			if err != nil {
+				panic(fmt.Sprintf("chi: invalid regexp pattern '%s' in route param", segRexpat))
+			}
+			child.prefix = segRexpat
+			child.rex = rex
+		}
+
+		if segStartIdx == 0 {
+			// Route starts with a param
+			child.typ = segTyp
+
+			if segTyp == ntCatchAll {
+				segStartIdx = -1
+			} else {
+				segStartIdx = segEndIdx
+			}
+			if segStartIdx < 0 {
+				segStartIdx = len(search)
+			}
+			child.tail = segTail // for params, we set the tail
+
+			if segStartIdx != len(search) {
+				// add static edge for the remaining part, split the end.
+				// its not possible to have adjacent param nodes, so its certainly
+				// going to be a static node next.
+
+				search = search[segStartIdx:] // advance search position
+
+				nn := &node{
+					typ:    ntStatic,
+					label:  search[0],
+					prefix: search,
+				}
+				hn = child.addChild(nn, search)
+			}
+
+		} else if segStartIdx > 0 {
+			// Route has some param
+
+			// starts with a static segment
+			child.typ = ntStatic
+			child.prefix = search[:segStartIdx]
+			child.rex = nil
+
+			// add the param edge node
+			search = search[segStartIdx:]
+
+			nn := &node{
+				typ:   segTyp,
+				label: search[0],
+				tail:  segTail,
+			}
+			hn = child.addChild(nn, search)
+
+		}
+	}
+
+	n.children[child.typ] = append(n.children[child.typ], child)
+	n.children[child.typ].Sort()
+	return hn
+}
+
+func (n *node) replaceChild(label, tail byte, child *node) {
+	for i := 0; i < len(n.children[child.typ]); i++ {
+		if n.children[child.typ][i].label == label && n.children[child.typ][i].tail == tail {
+			n.children[child.typ][i] = child
+			n.children[child.typ][i].label = label
+			n.children[child.typ][i].tail = tail
+			return
+		}
+	}
+	panic("chi: replacing missing child")
+}
+
+func (n *node) getEdge(ntyp nodeTyp, label, tail byte, prefix string) *node {
+	nds := n.children[ntyp]
+	for i := 0; i < len(nds); i++ {
+		if nds[i].label == label && nds[i].tail == tail {
+			if ntyp == ntRegexp && nds[i].prefix != prefix {
+				continue
+			}
+			return nds[i]
+		}
+	}
+	return nil
+}
+
+func (n *node) setEndpoint(method methodTyp, handler http.Handler, pattern string) {
+	// Set the handler for the method type on the node
+	if n.endpoints == nil {
+		n.endpoints = make(endpoints)
+	}
+
+	paramKeys := patParamKeys(pattern)
+
+	if method&mSTUB == mSTUB {
+		n.endpoints.Value(mSTUB).handler = handler
+	}
+	if method&mALL == mALL {
+		h := n.endpoints.Value(mALL)
+		h.handler = handler
+		h.pattern = pattern
+		h.paramKeys = paramKeys
+		for _, m := range methodMap {
+			h := n.endpoints.Value(m)
+			h.handler = handler
+			h.pattern = pattern
+			h.paramKeys = paramKeys
+		}
+	} else {
+		h := n.endpoints.Value(method)
+		h.handler = handler
+		h.pattern = pattern
+		h.paramKeys = paramKeys
+	}
+}
+
+func (n *node) FindRoute(rctx *Context, method methodTyp, path string) (*node, endpoints, http.Handler) {
+	// Reset the context routing pattern and params
+	rctx.routePattern = ""
+	rctx.routeParams.Keys = rctx.routeParams.Keys[:0]
+	rctx.routeParams.Values = rctx.routeParams.Values[:0]
+
+	// Find the routing handlers for the path
+	rn := n.findRoute(rctx, method, path)
+	if rn == nil {
+		return nil, nil, nil
+	}
+
+	// Record the routing params in the request lifecycle
+	rctx.URLParams.Keys = append(rctx.URLParams.Keys, rctx.routeParams.Keys...)
+	rctx.URLParams.Values = append(rctx.URLParams.Values, rctx.routeParams.Values...)
+
+	// Record the routing pattern in the request lifecycle
+	if rn.endpoints[method].pattern != "" {
+		rctx.routePattern = rn.endpoints[method].pattern
+		rctx.RoutePatterns = append(rctx.RoutePatterns, rctx.routePattern)
+	}
+
+	return rn, rn.endpoints, rn.endpoints[method].handler
+}
+
+// Recursive edge traversal by checking all nodeTyp groups along the way.
+// It's like searching through a multi-dimensional radix trie.
+func (n *node) findRoute(rctx *Context, method methodTyp, path string) *node {
+	nn := n
+	search := path
+
+	for t, nds := range nn.children {
+		ntyp := nodeTyp(t)
+		if len(nds) == 0 {
+			continue
+		}
+
+		var xn *node
+		xsearch := search
+
+		var label byte
+		if search != "" {
+			label = search[0]
+		}
+
+		switch ntyp {
+		case ntStatic:
+			xn = nds.findEdge(label)
+			if xn == nil || !strings.HasPrefix(xsearch, xn.prefix) {
+				continue
+			}
+			xsearch = xsearch[len(xn.prefix):]
+
+		case ntParam, ntRegexp:
+			// short-circuit and return no matching route for empty param values
+			if xsearch == "" {
+				continue
+			}
+
+			// serially loop through each node grouped by the tail delimiter
+			for idx := 0; idx < len(nds); idx++ {
+				xn = nds[idx]
+
+				// label for param nodes is the delimiter byte
+				p := strings.IndexByte(xsearch, xn.tail)
+
+				if p < 0 {
+					if xn.tail == '/' {
+						p = len(xsearch)
+					} else {
+						continue
+					}
+				} else if ntyp == ntRegexp && p == 0 {
+					continue
+				}
+
+				if ntyp == ntRegexp && xn.rex != nil {
+					if !xn.rex.MatchString(xsearch[:p]) {
+						continue
+					}
+				} else if strings.IndexByte(xsearch[:p], '/') != -1 {
+					// avoid a match across path segments
+					continue
+				}
+
+				prevlen := len(rctx.routeParams.Values)
+				rctx.routeParams.Values = append(rctx.routeParams.Values, xsearch[:p])
+				xsearch = xsearch[p:]
+
+				if len(xsearch) == 0 {
+					if xn.isLeaf() {
+						h := xn.endpoints[method]
+						if h != nil && h.handler != nil {
+							rctx.routeParams.Keys = append(rctx.routeParams.Keys, h.paramKeys...)
+							return xn
+						}
+
+						// flag that the routing context found a route, but not a corresponding
+						// supported method
+						rctx.methodNotAllowed = true
+					}
+				}
+
+				// recursively find the next node on this branch
+				fin := xn.findRoute(rctx, method, xsearch)
+				if fin != nil {
+					return fin
+				}
+
+				// not found on this branch, reset vars
+				rctx.routeParams.Values = rctx.routeParams.Values[:prevlen]
+				xsearch = search
+			}
+
+			rctx.routeParams.Values = append(rctx.routeParams.Values, "")
+
+		default:
+			// catch-all nodes
+			rctx.routeParams.Values = append(rctx.routeParams.Values, search)
+			xn = nds[0]
+			xsearch = ""
+		}
+
+		if xn == nil {
+			continue
+		}
+
+		// did we find it yet?
+		if len(xsearch) == 0 {
+			if xn.isLeaf() {
+				h := xn.endpoints[method]
+				if h != nil && h.handler != nil {
+					rctx.routeParams.Keys = append(rctx.routeParams.Keys, h.paramKeys...)
+					return xn
+				}
+
+				// flag that the routing context found a route, but not a corresponding
+				// supported method
+				rctx.methodNotAllowed = true
+			}
+		}
+
+		// recursively find the next node..
+		fin := xn.findRoute(rctx, method, xsearch)
+		if fin != nil {
+			return fin
+		}
+
+		// Did not find final handler, let's remove the param here if it was set
+		if xn.typ > ntStatic {
+			if len(rctx.routeParams.Values) > 0 {
+				rctx.routeParams.Values = rctx.routeParams.Values[:len(rctx.routeParams.Values)-1]
+			}
+		}
+
+	}
+
+	return nil
+}
+
+func (n *node) findEdge(ntyp nodeTyp, label byte) *node {
+	nds := n.children[ntyp]
+	num := len(nds)
+	idx := 0
+
+	switch ntyp {
+	case ntStatic, ntParam, ntRegexp:
+		i, j := 0, num-1
+		for i <= j {
+			idx = i + (j-i)/2
+			if label > nds[idx].label {
+				i = idx + 1
+			} else if label < nds[idx].label {
+				j = idx - 1
+			} else {
+				i = num // breaks cond
+			}
+		}
+		if nds[idx].label != label {
+			return nil
+		}
+		return nds[idx]
+
+	default: // catch all
+		return nds[idx]
+	}
+}
+
+func (n *node) isLeaf() bool {
+	return n.endpoints != nil
+}
+
+func (n *node) findPattern(pattern string) bool {
+	nn := n
+	for _, nds := range nn.children {
+		if len(nds) == 0 {
+			continue
+		}
+
+		n = nn.findEdge(nds[0].typ, pattern[0])
+		if n == nil {
+			continue
+		}
+
+		var idx int
+		var xpattern string
+
+		switch n.typ {
+		case ntStatic:
+			idx = longestPrefix(pattern, n.prefix)
+			if idx < len(n.prefix) {
+				continue
+			}
+
+		case ntParam, ntRegexp:
+			idx = strings.IndexByte(pattern, '}') + 1
+
+		case ntCatchAll:
+			idx = longestPrefix(pattern, "*")
+
+		default:
+			panic("chi: unknown node type")
+		}
+
+		xpattern = pattern[idx:]
+		if len(xpattern) == 0 {
+			return true
+		}
+
+		return n.findPattern(xpattern)
+	}
+	return false
+}
+
+func (n *node) routes() []Route {
+	rts := []Route{}
+
+	n.walk(func(eps endpoints, subroutes Routes) bool {
+		if eps[mSTUB] != nil && eps[mSTUB].handler != nil && subroutes == nil {
+			return false
+		}
+
+		// Group methodHandlers by unique patterns
+		pats := make(map[string]endpoints)
+
+		for mt, h := range eps {
+			if h.pattern == "" {
+				continue
+			}
+			p, ok := pats[h.pattern]
+			if !ok {
+				p = endpoints{}
+				pats[h.pattern] = p
+			}
+			p[mt] = h
+		}
+
+		for p, mh := range pats {
+			hs := make(map[string]http.Handler)
+			if mh[mALL] != nil && mh[mALL].handler != nil {
+				hs["*"] = mh[mALL].handler
+			}
+
+			for mt, h := range mh {
+				if h.handler == nil {
+					continue
+				}
+				m := methodTypString(mt)
+				if m == "" {
+					continue
+				}
+				hs[m] = h.handler
+			}
+
+			rt := Route{subroutes, hs, p}
+			rts = append(rts, rt)
+		}
+
+		return false
+	})
+
+	return rts
+}
+
+func (n *node) walk(fn func(eps endpoints, subroutes Routes) bool) bool {
+	// Visit the leaf values if any
+	if (n.endpoints != nil || n.subroutes != nil) && fn(n.endpoints, n.subroutes) {
+		return true
+	}
+
+	// Recurse on the children
+	for _, ns := range n.children {
+		for _, cn := range ns {
+			if cn.walk(fn) {
+				return true
+			}
+		}
+	}
+	return false
+}
+
+// patNextSegment returns the next segment details from a pattern:
+// node type, param key, regexp string, param tail byte, param starting index, param ending index
+func patNextSegment(pattern string) (nodeTyp, string, string, byte, int, int) {
+	ps := strings.Index(pattern, "{")
+	ws := strings.Index(pattern, "*")
+
+	if ps < 0 && ws < 0 {
+		return ntStatic, "", "", 0, 0, len(pattern) // we return the entire thing
+	}
+
+	// Sanity check
+	if ps >= 0 && ws >= 0 && ws < ps {
+		panic("chi: wildcard '*' must be the last pattern in a route, otherwise use a '{param}'")
+	}
+
+	var tail byte = '/' // Default endpoint tail to / byte
+
+	if ps >= 0 {
+		// Param/Regexp pattern is next
+		nt := ntParam
+
+		// Read to closing } taking into account opens and closes in curl count (cc)
+		cc := 0
+		pe := ps
+		for i, c := range pattern[ps:] {
+			if c == '{' {
+				cc++
+			} else if c == '}' {
+				cc--
+				if cc == 0 {
+					pe = ps + i
+					break
+				}
+			}
+		}
+		if pe == ps {
+			panic("chi: route param closing delimiter '}' is missing")
+		}
+
+		key := pattern[ps+1 : pe]
+		pe++ // set end to next position
+
+		if pe < len(pattern) {
+			tail = pattern[pe]
+		}
+
+		var rexpat string
+		if idx := strings.Index(key, ":"); idx >= 0 {
+			nt = ntRegexp
+			rexpat = key[idx+1:]
+			key = key[:idx]
+		}
+
+		if len(rexpat) > 0 {
+			if rexpat[0] != '^' {
+				rexpat = "^" + rexpat
+			}
+			if rexpat[len(rexpat)-1] != '$' {
+				rexpat += "$"
+			}
+		}
+
+		return nt, key, rexpat, tail, ps, pe
+	}
+
+	// Wildcard pattern as finale
+	if ws < len(pattern)-1 {
+		panic("chi: wildcard '*' must be the last value in a route. trim trailing text or use a '{param}' instead")
+	}
+	return ntCatchAll, "*", "", 0, ws, len(pattern)
+}
+
+func patParamKeys(pattern string) []string {
+	pat := pattern
+	paramKeys := []string{}
+	for {
+		ptyp, paramKey, _, _, _, e := patNextSegment(pat)
+		if ptyp == ntStatic {
+			return paramKeys
+		}
+		for i := 0; i < len(paramKeys); i++ {
+			if paramKeys[i] == paramKey {
+				panic(fmt.Sprintf("chi: routing pattern '%s' contains duplicate param key, '%s'", pattern, paramKey))
+			}
+		}
+		paramKeys = append(paramKeys, paramKey)
+		pat = pat[e:]
+	}
+}
+
+// longestPrefix finds the length of the shared prefix
+// of two strings
+func longestPrefix(k1, k2 string) int {
+	max := len(k1)
+	if l := len(k2); l < max {
+		max = l
+	}
+	var i int
+	for i = 0; i < max; i++ {
+		if k1[i] != k2[i] {
+			break
+		}
+	}
+	return i
+}
+
+func methodTypString(method methodTyp) string {
+	for s, t := range methodMap {
+		if method == t {
+			return s
+		}
+	}
+	return ""
+}
+
+type nodes []*node
+
+// Sort the list of nodes by label
+func (ns nodes) Sort()              { sort.Sort(ns); ns.tailSort() }
+func (ns nodes) Len() int           { return len(ns) }
+func (ns nodes) Swap(i, j int)      { ns[i], ns[j] = ns[j], ns[i] }
+func (ns nodes) Less(i, j int) bool { return ns[i].label < ns[j].label }
+
+// tailSort pushes nodes with '/' as the tail to the end of the list for param nodes.
+// The list order determines the traversal order.
+func (ns nodes) tailSort() {
+	for i := len(ns) - 1; i >= 0; i-- {
+		if ns[i].typ > ntStatic && ns[i].tail == '/' {
+			ns.Swap(i, len(ns)-1)
+			return
+		}
+	}
+}
+
+func (ns nodes) findEdge(label byte) *node {
+	num := len(ns)
+	idx := 0
+	i, j := 0, num-1
+	for i <= j {
+		idx = i + (j-i)/2
+		if label > ns[idx].label {
+			i = idx + 1
+		} else if label < ns[idx].label {
+			j = idx - 1
+		} else {
+			i = num // breaks cond
+		}
+	}
+	if ns[idx].label != label {
+		return nil
+	}
+	return ns[idx]
+}
+
+// Route describes the details of a routing handler.
+// Handlers map key is an HTTP method
+type Route struct {
+	SubRoutes Routes
+	Handlers  map[string]http.Handler
+	Pattern   string
+}
+
+// WalkFunc is the type of the function called for each method and route visited by Walk.
+type WalkFunc func(method string, route string, handler http.Handler, middlewares ...func(http.Handler) http.Handler) error
+
+// Walk walks any router tree that implements Routes interface.
+func Walk(r Routes, walkFn WalkFunc) error {
+	return walk(r, walkFn, "")
+}
+
+func walk(r Routes, walkFn WalkFunc, parentRoute string, parentMw ...func(http.Handler) http.Handler) error {
+	for _, route := range r.Routes() {
+		mws := make([]func(http.Handler) http.Handler, len(parentMw))
+		copy(mws, parentMw)
+		mws = append(mws, r.Middlewares()...)
+
+		if route.SubRoutes != nil {
+			if err := walk(route.SubRoutes, walkFn, parentRoute+route.Pattern, mws...); err != nil {
+				return err
+			}
+			continue
+		}
+
+		for method, handler := range route.Handlers {
+			if method == "*" {
+				// Ignore a "catchAll" method, since we pass down all the specific methods for each route.
+				continue
+			}
+
+			fullRoute := parentRoute + route.Pattern
+			fullRoute = strings.Replace(fullRoute, "/*/", "/", -1)
+
+			if chain, ok := handler.(*ChainHandler); ok {
+				if err := walkFn(method, fullRoute, chain.Endpoint, append(mws, chain.Middlewares...)...); err != nil {
+					return err
+				}
+			} else {
+				if err := walkFn(method, fullRoute, handler, mws...); err != nil {
+					return err
+				}
+			}
+		}
+	}
+
+	return nil
+}