tree.go at master ⋅ gin-gonic/gin

// Copyright 2013 Julien Schmidt. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be found
// at https://github.com/julienschmidt/httprouter/blob/master/LICENSE

package gin

import (
	"bytes"
	"net/url"
	"strings"
	"unicode"
	"unicode/utf8"

	"github.com/gin-gonic/gin/internal/bytesconv"
)

var (
	strColon = []byte(":")
	strStar  = []byte("*")
)

// Param is a single URL parameter, consisting of a key and a value.
type Param struct {
	Key   string
	Value string
}

// Params is a Param-slice, as returned by the router.
// The slice is ordered, the first URL parameter is also the first slice value.
// It is therefore safe to read values by the index.
type Params []Param

// Get returns the value of the first Param which key matches the given name.
// If no matching Param is found, an empty string is returned.
func (ps Params) Get(name string) (string, bool) {
	for _, entry := range ps {
		if entry.Key == name {
			return entry.Value, true
		}
	}
	return "", false
}

// ByName returns the value of the first Param which key matches the given name.
// If no matching Param is found, an empty string is returned.
func (ps Params) ByName(name string) (va string) {
	va, _ = ps.Get(name)
	return
}

type methodTree struct {
	method string
	root   *node
}

type methodTrees []methodTree

func (trees methodTrees) get(method string) *node {
	for _, tree := range trees {
		if tree.method == method {
			return tree.root
		}
	}
	return nil
}

func min(a, b int) int {
	if a <= b {
		return a
	}
	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) uint16 {
	var n uint16
	s := bytesconv.StringToBytes(path)
	n += uint16(bytes.Count(s, strColon))
	n += uint16(bytes.Count(s, strStar))
	return n
}

type nodeType uint8

const (
	static nodeType = iota // default
	root
	param
	catchAll
)

type node struct {
	path      string
	indices   string
	wildChild bool
	nType     nodeType
	priority  uint32
	children  []*node
	handlers  HandlersChain
	fullPath  string
}

// Increments priority of the given child and reorders if necessary
func (n *node) incrementChildPrio(pos int) int {
	cs := n.children
	cs[pos].priority++
	prio := cs[pos].priority

	// Adjust position (move to front)
	newPos := pos
	for ; newPos > 0 && cs[newPos-1].priority < prio; newPos-- {
		// Swap node positions
		cs[newPos-1], cs[newPos] = cs[newPos], cs[newPos-1]

	}

	// Build new index char string
	if newPos != pos {
		n.indices = n.indices[:newPos] + // Unchanged prefix, might be empty
			n.indices[pos:pos+1] + // The index char we move
			n.indices[newPos:pos] + n.indices[pos+1:] // Rest without char at 'pos'
	}

	return newPos
}

// addRoute adds a node with the given handle to the path.
// Not concurrency-safe!
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:]

			if n.wildChild {
				parentFullPathIndex += len(n.path)
				n = n.children[0]
				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
				}

				pathSeg := path
				if n.nType != catchAll {
					pathSeg = strings.SplitN(path, "/", 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 +
					"'")
			}

			c := path[0]

			// slash 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 != '*' {
				// []byte for proper unicode char conversion, see #65
				n.indices += bytesconv.BytesToString([]byte{c})
				child := &node{
					fullPath: fullPath,
				}
				n.children = append(n.children, child)
				n.incrementChildPrio(len(n.indices) - 1)
				n = child
			}
			n.insertChild(path, fullPath, handlers)
			return
		}

		// Otherwise and handle to current node
		if n.handlers != nil {
			panic("handlers are already registered for path '" + fullPath + "'")
		}
		n.handlers = handlers
		n.fullPath = fullPath
		return
	}
}

// Search for a wildcard segment and check the name for invalid characters.
// Returns -1 as index, if no wildcard was found.
func findWildcard(path string) (wildcard string, i int, valid bool) {
	// Find start
	for start, c := range []byte(path) {
		// A wildcard starts with ':' (param) or '*' (catch-all)
		if c != ':' && c != '*' {
			continue
		}

		// Find end and check for invalid characters
		valid = true
		for end, c := range []byte(path[start+1:]) {
			switch c {
			case '/':
				return path[start : start+1+end], start, valid
			case ':', '*':
				valid = false
			}
		}
		return path[start:], start, valid
	}
	return "", -1, false
}

func (n *node) insertChild(path string, fullPath string, handlers HandlersChain) {
	for {
		// Find prefix until first wildcard
		wildcard, i, valid := findWildcard(path)
		if i < 0 { // No wildcard found
			break
		}

		// The wildcard name must not contain ':' and '*'
		if !valid {
			panic("only one wildcard per path segment is allowed, has: '" +
				wildcard + "' in path '" + fullPath + "'")
		}

		// check if the wildcard has a name
		if len(wildcard) < 2 {
			panic("wildcards must be named with a non-empty name in path '" + fullPath + "'")
		}

		// Check if this node has existing children which would be
		// unreachable if we insert the wildcard here
		if len(n.children) > 0 {
			panic("wildcard segment '" + wildcard +
				"' conflicts with existing children in path '" + fullPath + "'")
		}

		if wildcard[0] == ':' { // param
			if i > 0 {
				// Insert prefix before the current wildcard
				n.path = path[:i]
				path = path[i:]
			}

			n.wildChild = true
			child := &node{
				nType:    param,
				path:     wildcard,
				fullPath: fullPath,
			}
			n.children = []*node{child}
			n = child
			n.priority++

			// if the path doesn't end with the wildcard, then there
			// will be another non-wildcard subpath starting with '/'
			if len(wildcard) < len(path) {
				path = path[len(wildcard):]

				child := &node{
					priority: 1,
					fullPath: fullPath,
				}
				n.children = []*node{child}
				n = child
				continue
			}

			// Otherwise we're done. Insert the handle in the new leaf
			n.handlers = handlers
			return
		}

		// catchAll
		if i+len(wildcard) != len(path) {
			panic("catch-all routes are only allowed at the end of the path in path '" + fullPath + "'")
		}

		if len(n.path) > 0 && n.path[len(n.path)-1] == '/' {
			panic("catch-all conflicts with existing handle for the path segment root in path '" + fullPath + "'")
		}

		// currently fixed width 1 for '/'
		i--
		if path[i] != '/' {
			panic("no / before catch-all in path '" + fullPath + "'")
		}

		n.path = path[:i]

		// First node: catchAll node with empty path
		child := &node{
			wildChild: true,
			nType:     catchAll,
			fullPath:  fullPath,
		}

		n.children = []*node{child}
		n.indices = string('/')
		n = child
		n.priority++

		// second node: node holding the variable
		child = &node{
			path:     path[i:],
			nType:    catchAll,
			handlers: handlers,
			priority: 1,
			fullPath: fullPath,
		}
		n.children = []*node{child}

		return
	}

	// If no wildcard was found, simply insert the path and handle
	n.path = path
	n.handlers = handlers
	n.fullPath = fullPath
}

// nodeValue holds return values of (*Node).getValue method
type nodeValue struct {
	handlers HandlersChain
	params   *Params
	tsr      bool
	fullPath string
}

// Returns the handle registered with the given path (key). The values of
// wildcards are saved to a map.
// If no handle can be found, a TSR (trailing slash redirect) recommendation is
// made if a handle exists with an extra (without the) trailing slash for the
// given path.
func (n *node) getValue(path string, params *Params, unescape bool) (value nodeValue) {
walk: // Outer loop for walking the tree
	for {
		prefix := n.path
		if len(path) > len(prefix) {
			if path[:len(prefix)] == prefix {
				path = path[len(prefix):]
				// 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
				if !n.wildChild {
					idxc := path[0]
					for i, c := range []byte(n.indices) {
						if c == idxc {
							n = n.children[i]
							continue walk
						}
					}

					// Nothing found.
					// We can recommend to redirect to the same URL without a
					// trailing slash if a leaf exists for that path.
					value.tsr = (path == "/" && n.handlers != nil)
					return
				}

				// Handle wildcard child
				n = n.children[0]
				switch n.nType {
				case param:
					// Find param end (either '/' or path end)
					end := 0
					for end < len(path) && path[end] != '/' {
						end++
					}

					// Save param value
					if params != nil {
						if value.params == nil {
							value.params = params
						}
						// Expand slice within preallocated capacity
						i := len(*value.params)
						*value.params = (*value.params)[:i+1]
						val := path[:end]
						if unescape {
							if v, err := url.QueryUnescape(val); err == nil {
								val = v
							}
						}
						(*value.params)[i] = Param{
							Key:   n.path[1:],
							Value: val,
						}
					}

					// we need to go deeper!
					if end < len(path) {
						if len(n.children) > 0 {
							path = path[end:]
							n = n.children[0]
							continue walk
						}

						// ... but we can't
						value.tsr = (len(path) == end+1)
						return
					}

					if value.handlers = n.handlers; value.handlers != nil {
						value.fullPath = n.fullPath
						return
					}
					if len(n.children) == 1 {
						// No handle found. Check if a handle for this path + a
						// trailing slash exists for TSR recommendation
						n = n.children[0]
						value.tsr = (n.path == "/" && n.handlers != nil)
					}
					return

				case catchAll:
					// Save param value
					if params != nil {
						if value.params == nil {
							value.params = params
						}
						// Expand slice within preallocated capacity
						i := len(*value.params)
						*value.params = (*value.params)[:i+1]
						val := path
						if unescape {
							if v, err := url.QueryUnescape(path); err == nil {
								val = v
							}
						}
						(*value.params)[i] = Param{
							Key:   n.path[2:],
							Value: val,
						}
					}

					value.handlers = n.handlers
					value.fullPath = n.fullPath
					return

				default:
					panic("invalid node type")
				}
			}
		}

		if path == prefix {
			// We should have reached the node containing the handle.
			// Check if this node has a handle registered.
			if value.handlers = n.handlers; value.handlers != nil {
				value.fullPath = n.fullPath
				return
			}

			// If there is no handle for this route, but this route has a
			// wildcard child, there must be a handle for this path with an
			// additional trailing slash
			if path == "/" && n.wildChild && n.nType != root {
				value.tsr = true
				return
			}

			// No handle found. Check if a handle for this path + a
			// trailing slash exists for trailing slash recommendation
			for i, c := range []byte(n.indices) {
				if c == '/' {
					n = n.children[i]
					value.tsr = (len(n.path) == 1 && n.handlers != nil) ||
						(n.nType == catchAll && n.children[0].handlers != nil)
					return
				}
			}

			return
		}

		// Nothing found. We can recommend to redirect to the same URL with an
		// extra trailing slash if a leaf exists for that path
		value.tsr = (path == "/") ||
			(len(prefix) == len(path)+1 && prefix[len(path)] == '/' &&
				path == prefix[:len(prefix)-1] && n.handlers != nil)
		return
	}
}

// Makes a case-insensitive lookup of the given path and tries to find a handler.
// It can optionally also fix trailing slashes.
// It returns the case-corrected path and a bool indicating whether the lookup
// was successful.
func (n *node) findCaseInsensitivePath(path string, fixTrailingSlash bool) ([]byte, bool) {
	const stackBufSize = 128

	// Use a static sized buffer on the stack in the common case.
	// If the path is too long, allocate a buffer on the heap instead.
	buf := make([]byte, 0, stackBufSize)
	if l := len(path) + 1; l > stackBufSize {
		buf = make([]byte, 0, l)
	}

	ciPath := n.findCaseInsensitivePathRec(
		path,
		buf,       // Preallocate enough memory for new path
		[4]byte{}, // Empty rune buffer
		fixTrailingSlash,
	)

	return ciPath, ciPath != nil
}

// Shift bytes in array by n bytes left
func shiftNRuneBytes(rb [4]byte, n int) [4]byte {
	switch n {
	case 0:
		return rb
	case 1:
		return [4]byte{rb[1], rb[2], rb[3], 0}
	case 2:
		return [4]byte{rb[2], rb[3]}
	case 3:
		return [4]byte{rb[3]}
	default:
		return [4]byte{}
	}
}

// Recursive case-insensitive lookup function used by n.findCaseInsensitivePath
func (n *node) findCaseInsensitivePathRec(path string, ciPath []byte, rb [4]byte, fixTrailingSlash bool) []byte {
	npLen := len(n.path)

walk: // Outer loop for walking the tree
	for len(path) >= npLen && (npLen == 0 || strings.EqualFold(path[1:npLen], n.path[1:])) {
		// Add common prefix to result
		oldPath := path
		path = path[npLen:]
		ciPath = append(ciPath, n.path...)

		if len(path) > 0 {
			// 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
			if !n.wildChild {
				// Skip rune bytes already processed
				rb = shiftNRuneBytes(rb, npLen)

				if rb[0] != 0 {
					// Old rune not finished
					idxc := rb[0]
					for i, c := range []byte(n.indices) {
						if c == idxc {
							// continue with child node
							n = n.children[i]
							npLen = len(n.path)
							continue walk
						}
					}
				} else {
					// Process a new rune
					var rv rune

					// Find rune start.
					// Runes are up to 4 byte long,
					// -4 would definitely be another rune.
					var off int
					for max := min(npLen, 3); off < max; off++ {
						if i := npLen - off; utf8.RuneStart(oldPath[i]) {
							// read rune from cached path
							rv, _ = utf8.DecodeRuneInString(oldPath[i:])
							break
						}
					}

					// Calculate lowercase bytes of current rune
					lo := unicode.ToLower(rv)
					utf8.EncodeRune(rb[:], lo)

					// Skip already processed bytes
					rb = shiftNRuneBytes(rb, off)

					idxc := rb[0]
					for i, c := range []byte(n.indices) {
						// Lowercase matches
						if c == idxc {
							// must use a recursive approach since both the
							// uppercase byte and the lowercase byte might exist
							// as an index
							if out := n.children[i].findCaseInsensitivePathRec(
								path, ciPath, rb, fixTrailingSlash,
							); out != nil {
								return out
							}
							break
						}
					}

					// If we found no match, the same for the uppercase rune,
					// if it differs
					if up := unicode.ToUpper(rv); up != lo {
						utf8.EncodeRune(rb[:], up)
						rb = shiftNRuneBytes(rb, off)

						idxc := rb[0]
						for i, c := range []byte(n.indices) {
							// Uppercase matches
							if c == idxc {
								// Continue with child node
								n = n.children[i]
								npLen = len(n.path)
								continue walk
							}
						}
					}
				}

				// Nothing found. We can recommend to redirect to the same URL
				// without a trailing slash if a leaf exists for that path
				if fixTrailingSlash && path == "/" && n.handlers != nil {
					return ciPath
				}
				return nil
			}

			n = n.children[0]
			switch n.nType {
			case param:
				// Find param end (either '/' or path end)
				end := 0
				for end < len(path) && path[end] != '/' {
					end++
				}

				// Add param value to case insensitive path
				ciPath = append(ciPath, path[:end]...)

				// We need to go deeper!
				if end < len(path) {
					if len(n.children) > 0 {
						// Continue with child node
						n = n.children[0]
						npLen = len(n.path)
						path = path[end:]
						continue
					}

					// ... but we can't
					if fixTrailingSlash && len(path) == end+1 {
						return ciPath
					}
					return nil
				}

				if n.handlers != nil {
					return ciPath
				}

				if fixTrailingSlash && len(n.children) == 1 {
					// No handle found. Check if a handle for this path + a
					// trailing slash exists
					n = n.children[0]
					if n.path == "/" && n.handlers != nil {
						return append(ciPath, '/')
					}
				}

				return nil

			case catchAll:
				return append(ciPath, path...)

			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
			}

			// No handle found.
			// Try to fix the path by adding a trailing slash
			if fixTrailingSlash {
				for i, c := range []byte(n.indices) {
					if c == '/' {
						n = n.children[i]
						if (len(n.path) == 1 && n.handlers != nil) ||
							(n.nType == catchAll && n.children[0].handlers != nil) {
							return append(ciPath, '/')
						}
						return nil
					}
				}
			}
			return nil
		}
	}

	// Nothing found.
	// Try to fix the path by adding / removing a trailing slash
	if fixTrailingSlash {
		if path == "/" {
			return ciPath
		}
		if len(path)+1 == npLen && n.path[len(path)] == '/' &&
			strings.EqualFold(path[1:], n.path[1:len(path)]) && n.handlers != nil {
			return append(ciPath, n.path...)
		}
	}
	return nil
}

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1		// Copyright 2013 Julien Schmidt. All rights reserved.
2		// Use of this source code is governed by a BSD-style license that can be found
3		// at https://github.com/julienschmidt/httprouter/blob/master/LICENSE
4
5		package gin
6
7		import (
8		"bytes"
9		"net/url"
10		"strings"
11		"unicode"
12		"unicode/utf8"
13
14		"github.com/gin-gonic/gin/internal/bytesconv"
15		)
16
17		var (
18		strColon = []byte(":")
19		strStar = []byte("*")
20		)
21
22		// Param is a single URL parameter, consisting of a key and a value.
23		type Param struct {
24		Key string
25		Value string
26		}
27
28		// Params is a Param-slice, as returned by the router.
29		// The slice is ordered, the first URL parameter is also the first slice value.
30		// It is therefore safe to read values by the index.
31		type Params []Param
32
33		// Get returns the value of the first Param which key matches the given name.
34		// If no matching Param is found, an empty string is returned.
35		func (ps Params) Get(name string) (string, bool) {
36		for _, entry := range ps {
37	14	if entry.Key == name {
38	14	return entry.Value, true
39		}
40		}
41	14	return "", false
42		}
43
44		// ByName returns the value of the first Param which key matches the given name.
45		// If no matching Param is found, an empty string is returned.
46		func (ps Params) ByName(name string) (va string) {
47	14	va, _ = ps.Get(name)
48	14	return
49		}
50
51		type methodTree struct {
52		method string
53		root *node
54		}
55
56		type methodTrees []methodTree
57
58		func (trees methodTrees) get(method string) *node {
59		for _, tree := range trees {
60	14	if tree.method == method {
61	14	return tree.root
62		}
63		}
64	14	return nil
65		}
66
67		func min(a, b int) int {
68	14	if a <= b {
69	14	return a
70		}
71	14	return b
72		}
73
74		func longestCommonPrefix(a, b string) int {
75	14	i := 0
76	14	max := min(len(a), len(b))
77		for i < max && a[i] == b[i] {
78	14	i++
79		}
80	14	return i
81		}
82
83		func countParams(path string) uint16 {
84	14	var n uint16
85	14	s := bytesconv.StringToBytes(path)
86	14	n += uint16(bytes.Count(s, strColon))
87	14	n += uint16(bytes.Count(s, strStar))
88	14	return n
89		}
90
91		type nodeType uint8
92
93		const (
94		static nodeType = iota // default
95		root
96		param
97		catchAll
98		)
99
100		type node struct {
101		path string
102		indices string
103		wildChild bool
104		nType nodeType
105		priority uint32
106		children []*node
107		handlers HandlersChain
108		fullPath string
109		}
110
111		// Increments priority of the given child and reorders if necessary
112		func (n *node) incrementChildPrio(pos int) int {
113	14	cs := n.children
114	14	cs[pos].priority++
115	14	prio := cs[pos].priority
116
117		// Adjust position (move to front)
118	14	newPos := pos
119		for ; newPos > 0 && cs[newPos-1].priority < prio; newPos-- {
120		// Swap node positions
121	14	cs[newPos-1], cs[newPos] = cs[newPos], cs[newPos-1]
122
123		}
124
125		// Build new index char string
126	14	if newPos != pos {
127	14	n.indices = n.indices[:newPos] + // Unchanged prefix, might be empty
128	14	n.indices[pos:pos+1] + // The index char we move
129	14	n.indices[newPos:pos] + n.indices[pos+1:] // Rest without char at 'pos'
130		}
131
132	14	return newPos
133		}
134
135		// addRoute adds a node with the given handle to the path.
136		// Not concurrency-safe!
137		func (n *node) addRoute(path string, handlers HandlersChain) {
138	14	fullPath := path
139	14	n.priority++
140
141		// Empty tree
142	14	if len(n.path) == 0 && len(n.children) == 0 {
143	14	n.insertChild(path, fullPath, handlers)
144	14	n.nType = root
145	14	return
146		}
147
148	14	parentFullPathIndex := 0
149
150	14	walk:
151		for {
152		// Find the longest common prefix.
153		// This also implies that the common prefix contains no ':' or '*'
154		// since the existing key can't contain those chars.
155	14	i := longestCommonPrefix(path, n.path)
156
157		// Split edge
158	14	if i < len(n.path) {
159		child := node{
160	14	path: n.path[i:],
161	14	wildChild: n.wildChild,
162	14	indices: n.indices,
163	14	children: n.children,
164	14	handlers: n.handlers,
165	14	priority: n.priority - 1,
166	14	fullPath: n.fullPath,
167		}
168
169	14	n.children = []*node{&child}
170		// []byte for proper unicode char conversion, see #65
171	14	n.indices = bytesconv.BytesToString([]byte{n.path[i]})
172	14	n.path = path[:i]
173	14	n.handlers = nil
174	14	n.wildChild = false
175	14	n.fullPath = fullPath[:parentFullPathIndex+i]
176		}
177
178		// Make new node a child of this node
179	14	if i < len(path) {
180	14	path = path[i:]
181
182	14	if n.wildChild {
183	14	parentFullPathIndex += len(n.path)
184	14	n = n.children[0]
185	14	n.priority++
186
187		// Check if the wildcard matches
188	14	if len(path) >= len(n.path) && n.path == path[:len(n.path)] &&
189		// Adding a child to a catchAll is not possible
190	14	n.nType != catchAll &&
191		// Check for longer wildcard, e.g. :name and :names
192	14	(len(n.path) >= len(path) \|\| path[len(n.path)] == '/') {
193	14	continue walk
194		}
195
196	14	pathSeg := path
197	14	if n.nType != catchAll {
198	14	pathSeg = strings.SplitN(path, "/", 2)[0]
199		}
200	14	prefix := fullPath[:strings.Index(fullPath, pathSeg)] + n.path
201	14	panic("'" + pathSeg +
202	14	"' in new path '" + fullPath +
203	14	"' conflicts with existing wildcard '" + n.path +
204	14	"' in existing prefix '" + prefix +
205	14	"'")
206		}
207
208	14	c := path[0]
209
210		// slash after param
211	14	if n.nType == param && c == '/' && len(n.children) == 1 {
212	14	parentFullPathIndex += len(n.path)
213	14	n = n.children[0]
214	14	n.priority++
215	14	continue walk
216		}
217
218		// Check if a child with the next path byte exists
219		for i, max := 0, len(n.indices); i < max; i++ {
220	14	if c == n.indices[i] {
221	14	parentFullPathIndex += len(n.path)
222	14	i = n.incrementChildPrio(i)
223	14	n = n.children[i]
224	14	continue walk
225		}
226		}
227
228		// Otherwise insert it
229	14	if c != ':' && c != '*' {
230		// []byte for proper unicode char conversion, see #65
231	14	n.indices += bytesconv.BytesToString([]byte{c})
232		child := &node{
233	14	fullPath: fullPath,
234		}
235	14	n.children = append(n.children, child)
236	14	n.incrementChildPrio(len(n.indices) - 1)
237	14	n = child
238		}
239	14	n.insertChild(path, fullPath, handlers)
240	14	return
241		}
242
243		// Otherwise and handle to current node
244	14	if n.handlers != nil {
245	14	panic("handlers are already registered for path '" + fullPath + "'")
246		}
247	14	n.handlers = handlers
248	14	n.fullPath = fullPath
249	14	return
250		}
251		}
252
253		// Search for a wildcard segment and check the name for invalid characters.
254		// Returns -1 as index, if no wildcard was found.
255		func findWildcard(path string) (wildcard string, i int, valid bool) {
256		// Find start
257		for start, c := range []byte(path) {
258		// A wildcard starts with ':' (param) or '*' (catch-all)
259	14	if c != ':' && c != '*' {
260	14	continue
261		}
262
263		// Find end and check for invalid characters
264	14	valid = true
265		for end, c := range []byte(path[start+1:]) {
266	14	switch c {
267	14	case '/':
268	14	return path[start : start+1+end], start, valid
269	14	case ':', '*':
270	14	valid = false
271		}
272		}
273	14	return path[start:], start, valid
274		}
275	14	return "", -1, false
276		}
277
278		func (n *node) insertChild(path string, fullPath string, handlers HandlersChain) {
279		for {
280		// Find prefix until first wildcard
281	14	wildcard, i, valid := findWildcard(path)
282	14	if i < 0 { // No wildcard found
283	14	break
284		}
285
286		// The wildcard name must not contain ':' and '*'
287	14	if !valid {
288	14	panic("only one wildcard per path segment is allowed, has: '" +
289	14	wildcard + "' in path '" + fullPath + "'")
290		}
291
292		// check if the wildcard has a name
293	14	if len(wildcard) < 2 {
294	14	panic("wildcards must be named with a non-empty name in path '" + fullPath + "'")
295		}
296
297		// Check if this node has existing children which would be
298		// unreachable if we insert the wildcard here
299	14	if len(n.children) > 0 {
300	14	panic("wildcard segment '" + wildcard +
301	14	"' conflicts with existing children in path '" + fullPath + "'")
302		}
303
304	14	if wildcard[0] == ':' { // param
305	14	if i > 0 {
306		// Insert prefix before the current wildcard
307	14	n.path = path[:i]
308	14	path = path[i:]
309		}
310
311	14	n.wildChild = true
312		child := &node{
313	14	nType: param,
314	14	path: wildcard,
315	14	fullPath: fullPath,
316		}
317	14	n.children = []*node{child}
318	14	n = child
319	14	n.priority++
320
321		// if the path doesn't end with the wildcard, then there
322		// will be another non-wildcard subpath starting with '/'
323	14	if len(wildcard) < len(path) {
324	14	path = path[len(wildcard):]
325
326		child := &node{
327	14	priority: 1,
328	14	fullPath: fullPath,
329		}
330	14	n.children = []*node{child}
331	14	n = child
332	14	continue
333		}
334
335		// Otherwise we're done. Insert the handle in the new leaf
336	14	n.handlers = handlers
337	14	return
338		}
339
340		// catchAll
341	14	if i+len(wildcard) != len(path) {
342	14	panic("catch-all routes are only allowed at the end of the path in path '" + fullPath + "'")
343		}
344
345	14	if len(n.path) > 0 && n.path[len(n.path)-1] == '/' {
346	14	panic("catch-all conflicts with existing handle for the path segment root in path '" + fullPath + "'")
347		}
348
349		// currently fixed width 1 for '/'
350	14	i--
351	14	if path[i] != '/' {
352	14	panic("no / before catch-all in path '" + fullPath + "'")
353		}
354
355	14	n.path = path[:i]
356
357		// First node: catchAll node with empty path
358		child := &node{
359	14	wildChild: true,
360	14	nType: catchAll,
361	14	fullPath: fullPath,
362		}
363
364	14	n.children = []*node{child}
365	14	n.indices = string('/')
366	14	n = child
367	14	n.priority++
368
369		// second node: node holding the variable
370		child = &node{
371	14	path: path[i:],
372	14	nType: catchAll,
373	14	handlers: handlers,
374	14	priority: 1,
375	14	fullPath: fullPath,
376		}
377	14	n.children = []*node{child}
378
379	14	return
380		}
381
382		// If no wildcard was found, simply insert the path and handle
383	14	n.path = path
384	14	n.handlers = handlers
385	14	n.fullPath = fullPath
386		}
387
388		// nodeValue holds return values of (*Node).getValue method
389		type nodeValue struct {
390		handlers HandlersChain
391		params *Params
392		tsr bool
393		fullPath string
394		}
395
396		// Returns the handle registered with the given path (key). The values of
397		// wildcards are saved to a map.
398		// If no handle can be found, a TSR (trailing slash redirect) recommendation is
399		// made if a handle exists with an extra (without the) trailing slash for the
400		// given path.
401		func (n node) getValue(path string, params Params, unescape bool) (value nodeValue) {
402	14	walk: // Outer loop for walking the tree
403		for {
404	14	prefix := n.path
405	14	if len(path) > len(prefix) {
406	14	if path[:len(prefix)] == prefix {
407	14	path = path[len(prefix):]
408		// If this node does not have a wildcard (param or catchAll)
409		// child, we can just look up the next child node and continue
410		// to walk down the tree
411	14	if !n.wildChild {
412	14	idxc := path[0]
413		for i, c := range []byte(n.indices) {
414	14	if c == idxc {
415	14	n = n.children[i]
416	14	continue walk
417		}
418		}
419
420		// Nothing found.
421		// We can recommend to redirect to the same URL without a
422		// trailing slash if a leaf exists for that path.
423	14	value.tsr = (path == "/" && n.handlers != nil)
424	14	return
425		}
426
427		// Handle wildcard child
428	14	n = n.children[0]
429	14	switch n.nType {
430	14	case param:
431		// Find param end (either '/' or path end)
432	14	end := 0
433		for end < len(path) && path[end] != '/' {
434	14	end++
435		}
436
437		// Save param value
438	14	if params != nil {
439	14	if value.params == nil {
440	14	value.params = params
441		}
442		// Expand slice within preallocated capacity
443	14	i := len(*value.params)
444	14	value.params = (value.params)[:i+1]
445	14	val := path[:end]
446	14	if unescape {
447	14	if v, err := url.QueryUnescape(val); err == nil {
448	14	val = v
449		}
450		}
451	14	(*value.params)[i] = Param{
452	14	Key: n.path[1:],
453	14	Value: val,
454		}
455		}
456
457		// we need to go deeper!
458	14	if end < len(path) {
459	14	if len(n.children) > 0 {
460	14	path = path[end:]
461	14	n = n.children[0]
462	14	continue walk
463		}
464
465		// ... but we can't
466	14	value.tsr = (len(path) == end+1)
467	14	return
468		}
469
470	14	if value.handlers = n.handlers; value.handlers != nil {
471	14	value.fullPath = n.fullPath
472	14	return
473		}
474	14	if len(n.children) == 1 {
475		// No handle found. Check if a handle for this path + a
476		// trailing slash exists for TSR recommendation
477	14	n = n.children[0]
478	14	value.tsr = (n.path == "/" && n.handlers != nil)
479		}
480	14	return
481
482	14	case catchAll:
483		// Save param value
484	14	if params != nil {
485	14	if value.params == nil {
486	14	value.params = params
487		}
488		// Expand slice within preallocated capacity
489	14	i := len(*value.params)
490	14	value.params = (value.params)[:i+1]
491	14	val := path
492	14	if unescape {
493	14	if v, err := url.QueryUnescape(path); err == nil {
494	14	val = v
495		}
496		}
497	14	(*value.params)[i] = Param{
498	14	Key: n.path[2:],
499	14	Value: val,
500		}
501		}
502
503	14	value.handlers = n.handlers
504	14	value.fullPath = n.fullPath
505	14	return
506
507	14	default:
508	14	panic("invalid node type")
509		}
510		}
511		}
512
513	14	if path == prefix {
514		// We should have reached the node containing the handle.
515		// Check if this node has a handle registered.
516	14	if value.handlers = n.handlers; value.handlers != nil {
517	14	value.fullPath = n.fullPath
518	14	return
519		}
520
521		// If there is no handle for this route, but this route has a
522		// wildcard child, there must be a handle for this path with an
523		// additional trailing slash
524	14	if path == "/" && n.wildChild && n.nType != root {
525	14	value.tsr = true
526	14	return
527		}
528
529		// No handle found. Check if a handle for this path + a
530		// trailing slash exists for trailing slash recommendation
531		for i, c := range []byte(n.indices) {
532	14	if c == '/' {
533	14	n = n.children[i]
534	14	value.tsr = (len(n.path) == 1 && n.handlers != nil) \|\|
535	14	(n.nType == catchAll && n.children[0].handlers != nil)
536	14	return
537		}
538		}
539
540	14	return
541		}
542
543		// Nothing found. We can recommend to redirect to the same URL with an
544		// extra trailing slash if a leaf exists for that path
545	14	value.tsr = (path == "/") \|\|
546	14	(len(prefix) == len(path)+1 && prefix[len(path)] == '/' &&
547	14	path == prefix[:len(prefix)-1] && n.handlers != nil)
548	14	return
549		}
550		}
551
552		// Makes a case-insensitive lookup of the given path and tries to find a handler.
553		// It can optionally also fix trailing slashes.
554		// It returns the case-corrected path and a bool indicating whether the lookup
555		// was successful.
556		func (n *node) findCaseInsensitivePath(path string, fixTrailingSlash bool) ([]byte, bool) {
557	14	const stackBufSize = 128
558
559		// Use a static sized buffer on the stack in the common case.
560		// If the path is too long, allocate a buffer on the heap instead.
561	14	buf := make([]byte, 0, stackBufSize)
562	14	if l := len(path) + 1; l > stackBufSize {
563	14	buf = make([]byte, 0, l)
564		}
565
566	14	ciPath := n.findCaseInsensitivePathRec(
567	14	path,
568	14	buf, // Preallocate enough memory for new path
569	14	[4]byte{}, // Empty rune buffer
570	14	fixTrailingSlash,
571	14	)
572
573	14	return ciPath, ciPath != nil
574		}
575
576		// Shift bytes in array by n bytes left
577		func shiftNRuneBytes(rb [4]byte, n int) [4]byte {
578	14	switch n {
579	14	case 0:
580	14	return rb
581	14	case 1:
582	14	return [4]byte{rb[1], rb[2], rb[3], 0}
583	14	case 2:
584	14	return [4]byte{rb[2], rb[3]}
585	14	case 3:
586	14	return [4]byte{rb[3]}
587	14	default:
588	14	return [4]byte{}
589		}
590		}
591
592		// Recursive case-insensitive lookup function used by n.findCaseInsensitivePath
593		func (n *node) findCaseInsensitivePathRec(path string, ciPath []byte, rb [4]byte, fixTrailingSlash bool) []byte {
594	14	npLen := len(n.path)
595
596	14	walk: // Outer loop for walking the tree
597		for len(path) >= npLen && (npLen == 0 \|\| strings.EqualFold(path[1:npLen], n.path[1:])) {
598		// Add common prefix to result
599	14	oldPath := path
600	14	path = path[npLen:]
601	14	ciPath = append(ciPath, n.path...)
602
603	14	if len(path) > 0 {
604		// If this node does not have a wildcard (param or catchAll) child,
605		// we can just look up the next child node and continue to walk down
606		// the tree
607	14	if !n.wildChild {
608		// Skip rune bytes already processed
609	14	rb = shiftNRuneBytes(rb, npLen)
610
611	14	if rb[0] != 0 {
612		// Old rune not finished
613	14	idxc := rb[0]
614		for i, c := range []byte(n.indices) {
615	14	if c == idxc {
616		// continue with child node
617	14	n = n.children[i]
618	14	npLen = len(n.path)
619	14	continue walk
620		}
621		}
622	14	} else {
623		// Process a new rune
624	14	var rv rune
625
626		// Find rune start.
627		// Runes are up to 4 byte long,
628		// -4 would definitely be another rune.
629	14	var off int
630		for max := min(npLen, 3); off < max; off++ {
631	14	if i := npLen - off; utf8.RuneStart(oldPath[i]) {
632		// read rune from cached path
633	14	rv, _ = utf8.DecodeRuneInString(oldPath[i:])
634	14	break
635		}
636		}
637
638		// Calculate lowercase bytes of current rune
639	14	lo := unicode.ToLower(rv)
640	14	utf8.EncodeRune(rb[:], lo)
641
642		// Skip already processed bytes
643	14	rb = shiftNRuneBytes(rb, off)
644
645	14	idxc := rb[0]
646		for i, c := range []byte(n.indices) {
647		// Lowercase matches
648	14	if c == idxc {
649		// must use a recursive approach since both the
650		// uppercase byte and the lowercase byte might exist
651		// as an index
652	14	if out := n.children[i].findCaseInsensitivePathRec(
653	14	path, ciPath, rb, fixTrailingSlash,
654	14	); out != nil {
655	14	return out
656		}
657	14	break
658		}
659		}
660
661		// If we found no match, the same for the uppercase rune,
662		// if it differs
663	14	if up := unicode.ToUpper(rv); up != lo {
664	14	utf8.EncodeRune(rb[:], up)
665	14	rb = shiftNRuneBytes(rb, off)
666
667	14	idxc := rb[0]
668		for i, c := range []byte(n.indices) {
669		// Uppercase matches
670	14	if c == idxc {
671		// Continue with child node
672	14	n = n.children[i]
673	14	npLen = len(n.path)
674	14	continue walk
675		}
676		}
677		}
678		}
679
680		// Nothing found. We can recommend to redirect to the same URL
681		// without a trailing slash if a leaf exists for that path
682	14	if fixTrailingSlash && path == "/" && n.handlers != nil {
683	14	return ciPath
684		}
685	14	return nil
686		}
687
688	14	n = n.children[0]
689	14	switch n.nType {
690	14	case param:
691		// Find param end (either '/' or path end)
692	14	end := 0
693		for end < len(path) && path[end] != '/' {
694	14	end++
695		}
696
697		// Add param value to case insensitive path
698	14	ciPath = append(ciPath, path[:end]...)
699
700		// We need to go deeper!
701	14	if end < len(path) {
702	14	if len(n.children) > 0 {
703		// Continue with child node
704	14	n = n.children[0]
705	14	npLen = len(n.path)
706	14	path = path[end:]
707	14	continue
708		}
709
710		// ... but we can't
711	14	if fixTrailingSlash && len(path) == end+1 {
712	14	return ciPath
713		}
714	14	return nil
715		}
716
717	14	if n.handlers != nil {
718	14	return ciPath
719		}
720
721	14	if fixTrailingSlash && len(n.children) == 1 {
722		// No handle found. Check if a handle for this path + a
723		// trailing slash exists
724	14	n = n.children[0]
725	14	if n.path == "/" && n.handlers != nil {
726	14	return append(ciPath, '/')
727		}
728		}
729
730	14	return nil
731
732	14	case catchAll:
733	14	return append(ciPath, path...)
734
735	14	default:
736	14	panic("invalid node type")
737		}
738	14	} else {
739		// We should have reached the node containing the handle.
740		// Check if this node has a handle registered.
741	14	if n.handlers != nil {
742	14	return ciPath
743		}
744
745		// No handle found.
746		// Try to fix the path by adding a trailing slash
747	14	if fixTrailingSlash {
748		for i, c := range []byte(n.indices) {
749	14	if c == '/' {
750	14	n = n.children[i]
751	14	if (len(n.path) == 1 && n.handlers != nil) \|\|
752	14	(n.nType == catchAll && n.children[0].handlers != nil) {
753	14	return append(ciPath, '/')
754		}
755	14	return nil
756		}
757		}
758		}
759	14	return nil
760		}
761		}
762
763		// Nothing found.
764		// Try to fix the path by adding / removing a trailing slash
765	14	if fixTrailingSlash {
766	14	if path == "/" {
767	14	return ciPath
768		}
769	14	if len(path)+1 == npLen && n.path[len(path)] == '/' &&
770	14	strings.EqualFold(path[1:], n.path[1:len(path)]) && n.handlers != nil {
771	14	return append(ciPath, n.path...)
772		}
773		}
774	14	return nil
775		}