657 lines
16 KiB
Go
657 lines
16 KiB
Go
// Copyright 2013 Julien Schmidt. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be found
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// in the LICENSE file.
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package httprouter
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import (
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"strings"
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"unicode"
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"unicode/utf8"
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)
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func min(a, b int) int {
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if a <= b {
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return a
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}
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return b
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}
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func countParams(path string) uint8 {
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var n uint
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for i := 0; i < len(path); i++ {
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if path[i] != ':' && path[i] != '*' {
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continue
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}
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n++
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}
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if n >= 255 {
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return 255
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}
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return uint8(n)
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}
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type nodeType uint8
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const (
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static nodeType = iota // default
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root
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param
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catchAll
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)
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type node struct {
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path string
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wildChild bool
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nType nodeType
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maxParams uint8
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indices string
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children []*node
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handle Handle
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priority uint32
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}
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// increments priority of the given child and reorders if necessary
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func (n *node) incrementChildPrio(pos int) int {
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n.children[pos].priority++
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prio := n.children[pos].priority
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// adjust position (move to front)
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newPos := pos
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for newPos > 0 && n.children[newPos-1].priority < prio {
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// swap node positions
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n.children[newPos-1], n.children[newPos] = n.children[newPos], n.children[newPos-1]
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newPos--
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}
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// build new index char string
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if newPos != pos {
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n.indices = n.indices[:newPos] + // unchanged prefix, might be empty
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n.indices[pos:pos+1] + // the index char we move
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n.indices[newPos:pos] + n.indices[pos+1:] // rest without char at 'pos'
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}
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return newPos
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}
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// addRoute adds a node with the given handle to the path.
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// Not concurrency-safe!
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func (n *node) addRoute(path string, handle Handle) {
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fullPath := path
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n.priority++
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numParams := countParams(path)
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// non-empty tree
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if len(n.path) > 0 || len(n.children) > 0 {
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walk:
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for {
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// Update maxParams of the current node
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if numParams > n.maxParams {
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n.maxParams = numParams
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}
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// Find the longest common prefix.
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// This also implies that the common prefix contains no ':' or '*'
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// since the existing key can't contain those chars.
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i := 0
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max := min(len(path), len(n.path))
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for i < max && path[i] == n.path[i] {
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i++
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}
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// Split edge
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if i < len(n.path) {
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child := node{
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path: n.path[i:],
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wildChild: n.wildChild,
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nType: static,
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indices: n.indices,
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children: n.children,
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handle: n.handle,
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priority: n.priority - 1,
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}
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// Update maxParams (max of all children)
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for i := range child.children {
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if child.children[i].maxParams > child.maxParams {
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child.maxParams = child.children[i].maxParams
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}
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}
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n.children = []*node{&child}
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// []byte for proper unicode char conversion, see #65
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n.indices = string([]byte{n.path[i]})
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n.path = path[:i]
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n.handle = nil
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n.wildChild = false
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}
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// Make new node a child of this node
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if i < len(path) {
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path = path[i:]
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if n.wildChild {
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n = n.children[0]
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n.priority++
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// Update maxParams of the child node
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if numParams > n.maxParams {
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n.maxParams = numParams
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}
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numParams--
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// Check if the wildcard matches
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if len(path) >= len(n.path) && n.path == path[:len(n.path)] &&
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// Check for longer wildcard, e.g. :name and :names
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(len(n.path) >= len(path) || path[len(n.path)] == '/') {
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continue walk
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} else {
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// Wildcard conflict
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var pathSeg string
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if n.nType == catchAll {
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pathSeg = path
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} else {
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pathSeg = strings.SplitN(path, "/", 2)[0]
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}
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prefix := fullPath[:strings.Index(fullPath, pathSeg)] + n.path
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panic("'" + pathSeg +
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"' in new path '" + fullPath +
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"' conflicts with existing wildcard '" + n.path +
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"' in existing prefix '" + prefix +
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"'")
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}
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}
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c := path[0]
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// slash after param
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if n.nType == param && c == '/' && len(n.children) == 1 {
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n = n.children[0]
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n.priority++
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continue walk
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}
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// Check if a child with the next path byte exists
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for i := 0; i < len(n.indices); i++ {
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if c == n.indices[i] {
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i = n.incrementChildPrio(i)
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n = n.children[i]
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continue walk
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}
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}
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// Otherwise insert it
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if c != ':' && c != '*' {
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// []byte for proper unicode char conversion, see #65
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n.indices += string([]byte{c})
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child := &node{
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maxParams: numParams,
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}
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n.children = append(n.children, child)
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n.incrementChildPrio(len(n.indices) - 1)
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n = child
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}
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n.insertChild(numParams, path, fullPath, handle)
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return
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} else if i == len(path) { // Make node a (in-path) leaf
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if n.handle != nil {
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panic("a handle is already registered for path '" + fullPath + "'")
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}
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n.handle = handle
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}
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return
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}
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} else { // Empty tree
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n.insertChild(numParams, path, fullPath, handle)
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n.nType = root
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}
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}
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func (n *node) insertChild(numParams uint8, path, fullPath string, handle Handle) {
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var offset int // already handled bytes of the path
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// find prefix until first wildcard (beginning with ':'' or '*'')
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for i, max := 0, len(path); numParams > 0; i++ {
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c := path[i]
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if c != ':' && c != '*' {
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continue
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}
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// find wildcard end (either '/' or path end)
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end := i + 1
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for end < max && path[end] != '/' {
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switch path[end] {
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// the wildcard name must not contain ':' and '*'
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case ':', '*':
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panic("only one wildcard per path segment is allowed, has: '" +
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path[i:] + "' in path '" + fullPath + "'")
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default:
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end++
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}
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}
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// check if this Node existing children which would be
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// unreachable if we insert the wildcard here
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if len(n.children) > 0 {
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panic("wildcard route '" + path[i:end] +
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"' conflicts with existing children in path '" + fullPath + "'")
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}
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// check if the wildcard has a name
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if end-i < 2 {
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panic("wildcards must be named with a non-empty name in path '" + fullPath + "'")
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}
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if c == ':' { // param
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// split path at the beginning of the wildcard
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if i > 0 {
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n.path = path[offset:i]
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offset = i
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}
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child := &node{
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nType: param,
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maxParams: numParams,
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}
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n.children = []*node{child}
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n.wildChild = true
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n = child
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n.priority++
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numParams--
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// if the path doesn't end with the wildcard, then there
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// will be another non-wildcard subpath starting with '/'
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if end < max {
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n.path = path[offset:end]
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offset = end
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child := &node{
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maxParams: numParams,
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priority: 1,
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}
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n.children = []*node{child}
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n = child
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}
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} else { // catchAll
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if end != max || numParams > 1 {
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panic("catch-all routes are only allowed at the end of the path in path '" + fullPath + "'")
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}
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if len(n.path) > 0 && n.path[len(n.path)-1] == '/' {
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panic("catch-all conflicts with existing handle for the path segment root in path '" + fullPath + "'")
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}
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// currently fixed width 1 for '/'
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i--
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if path[i] != '/' {
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panic("no / before catch-all in path '" + fullPath + "'")
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}
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n.path = path[offset:i]
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// first node: catchAll node with empty path
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child := &node{
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wildChild: true,
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nType: catchAll,
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maxParams: 1,
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}
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n.children = []*node{child}
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n.indices = string(path[i])
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n = child
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n.priority++
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// second node: node holding the variable
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child = &node{
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path: path[i:],
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nType: catchAll,
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maxParams: 1,
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handle: handle,
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priority: 1,
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}
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n.children = []*node{child}
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return
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}
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}
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// insert remaining path part and handle to the leaf
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n.path = path[offset:]
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n.handle = handle
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}
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// Returns the handle registered with the given path (key). The values of
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// wildcards are saved to a map.
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// If no handle can be found, a TSR (trailing slash redirect) recommendation is
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// made if a handle exists with an extra (without the) trailing slash for the
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// given path.
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func (n *node) getValue(path string) (handle Handle, p Params, tsr bool) {
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walk: // outer loop for walking the tree
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for {
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if len(path) > len(n.path) {
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if path[:len(n.path)] == n.path {
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path = path[len(n.path):]
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// If this node does not have a wildcard (param or catchAll)
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// child, we can just look up the next child node and continue
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// to walk down the tree
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if !n.wildChild {
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c := path[0]
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for i := 0; i < len(n.indices); i++ {
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if c == n.indices[i] {
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n = n.children[i]
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continue walk
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}
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}
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// Nothing found.
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// We can recommend to redirect to the same URL without a
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// trailing slash if a leaf exists for that path.
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tsr = (path == "/" && n.handle != nil)
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return
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}
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// handle wildcard child
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n = n.children[0]
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switch n.nType {
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case param:
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// find param end (either '/' or path end)
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end := 0
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for end < len(path) && path[end] != '/' {
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end++
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}
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// save param value
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if p == nil {
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// lazy allocation
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p = make(Params, 0, n.maxParams)
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}
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i := len(p)
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p = p[:i+1] // expand slice within preallocated capacity
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p[i].Key = n.path[1:]
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p[i].Value = path[:end]
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// we need to go deeper!
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if end < len(path) {
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if len(n.children) > 0 {
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path = path[end:]
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n = n.children[0]
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continue walk
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}
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// ... but we can't
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tsr = (len(path) == end+1)
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return
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}
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if handle = n.handle; handle != nil {
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return
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} else if len(n.children) == 1 {
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// No handle found. Check if a handle for this path + a
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// trailing slash exists for TSR recommendation
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n = n.children[0]
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tsr = (n.path == "/" && n.handle != nil)
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}
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return
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case catchAll:
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// save param value
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if p == nil {
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// lazy allocation
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p = make(Params, 0, n.maxParams)
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}
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i := len(p)
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p = p[:i+1] // expand slice within preallocated capacity
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p[i].Key = n.path[2:]
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p[i].Value = path
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handle = n.handle
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return
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default:
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panic("invalid node type")
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}
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}
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} else if path == n.path {
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// We should have reached the node containing the handle.
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// Check if this node has a handle registered.
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if handle = n.handle; handle != nil {
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return
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}
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if path == "/" && n.wildChild && n.nType != root {
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tsr = true
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return
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}
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// No handle found. Check if a handle for this path + a
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// trailing slash exists for trailing slash recommendation
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for i := 0; i < len(n.indices); i++ {
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if n.indices[i] == '/' {
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n = n.children[i]
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tsr = (len(n.path) == 1 && n.handle != nil) ||
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(n.nType == catchAll && n.children[0].handle != nil)
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return
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}
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}
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return
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}
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// Nothing found. We can recommend to redirect to the same URL with an
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// extra trailing slash if a leaf exists for that path
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tsr = (path == "/") ||
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(len(n.path) == len(path)+1 && n.path[len(path)] == '/' &&
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path == n.path[:len(n.path)-1] && n.handle != nil)
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return
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}
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}
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// Makes a case-insensitive lookup of the given path and tries to find a handler.
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// It can optionally also fix trailing slashes.
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// It returns the case-corrected path and a bool indicating whether the lookup
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// was successful.
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func (n *node) findCaseInsensitivePath(path string, fixTrailingSlash bool) (ciPath []byte, found bool) {
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return n.findCaseInsensitivePathRec(
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path,
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strings.ToLower(path),
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make([]byte, 0, len(path)+1), // preallocate enough memory for new path
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[4]byte{}, // empty rune buffer
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fixTrailingSlash,
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)
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}
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// shift bytes in array by n bytes left
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func shiftNRuneBytes(rb [4]byte, n int) [4]byte {
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switch n {
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case 0:
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return rb
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case 1:
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return [4]byte{rb[1], rb[2], rb[3], 0}
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case 2:
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return [4]byte{rb[2], rb[3]}
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case 3:
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return [4]byte{rb[3]}
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default:
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return [4]byte{}
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}
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}
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// recursive case-insensitive lookup function used by n.findCaseInsensitivePath
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func (n *node) findCaseInsensitivePathRec(path, loPath string, ciPath []byte, rb [4]byte, fixTrailingSlash bool) ([]byte, bool) {
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loNPath := strings.ToLower(n.path)
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walk: // outer loop for walking the tree
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for len(loPath) >= len(loNPath) && (len(loNPath) == 0 || loPath[1:len(loNPath)] == loNPath[1:]) {
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// add common path to result
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ciPath = append(ciPath, n.path...)
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if path = path[len(n.path):]; len(path) > 0 {
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loOld := loPath
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loPath = loPath[len(loNPath):]
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// If this node does not have a wildcard (param or catchAll) child,
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// we can just look up the next child node and continue to walk down
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// the tree
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if !n.wildChild {
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// skip rune bytes already processed
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rb = shiftNRuneBytes(rb, len(loNPath))
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if rb[0] != 0 {
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// old rune not finished
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for i := 0; i < len(n.indices); i++ {
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if n.indices[i] == rb[0] {
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// continue with child node
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n = n.children[i]
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loNPath = strings.ToLower(n.path)
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continue walk
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}
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}
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} else {
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// process a new rune
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var rv rune
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// find rune start
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// runes are up to 4 byte long,
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// -4 would definitely be another rune
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var off int
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for max := min(len(loNPath), 3); off < max; off++ {
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if i := len(loNPath) - off; utf8.RuneStart(loOld[i]) {
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// read rune from cached lowercase path
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rv, _ = utf8.DecodeRuneInString(loOld[i:])
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break
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}
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}
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// calculate lowercase bytes of current rune
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utf8.EncodeRune(rb[:], rv)
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// skipp already processed bytes
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rb = shiftNRuneBytes(rb, off)
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for i := 0; i < len(n.indices); i++ {
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// lowercase matches
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if n.indices[i] == rb[0] {
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// must use a recursive approach since both the
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// uppercase byte and the lowercase byte might exist
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// as an index
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if out, found := n.children[i].findCaseInsensitivePathRec(
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path, loPath, ciPath, rb, fixTrailingSlash,
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); found {
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return out, true
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}
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break
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}
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}
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// same for uppercase rune, if it differs
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if up := unicode.ToUpper(rv); up != rv {
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utf8.EncodeRune(rb[:], up)
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rb = shiftNRuneBytes(rb, off)
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for i := 0; i < len(n.indices); i++ {
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// uppercase matches
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if n.indices[i] == rb[0] {
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// continue with child node
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n = n.children[i]
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loNPath = strings.ToLower(n.path)
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continue walk
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}
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}
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}
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}
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|
// Nothing found. We can recommend to redirect to the same URL
|
|
// without a trailing slash if a leaf exists for that path
|
|
return ciPath, (fixTrailingSlash && path == "/" && n.handle != nil)
|
|
}
|
|
|
|
n = n.children[0]
|
|
switch n.nType {
|
|
case param:
|
|
// find param end (either '/' or path end)
|
|
k := 0
|
|
for k < len(path) && path[k] != '/' {
|
|
k++
|
|
}
|
|
|
|
// add param value to case insensitive path
|
|
ciPath = append(ciPath, path[:k]...)
|
|
|
|
// we need to go deeper!
|
|
if k < len(path) {
|
|
if len(n.children) > 0 {
|
|
// continue with child node
|
|
n = n.children[0]
|
|
loNPath = strings.ToLower(n.path)
|
|
loPath = loPath[k:]
|
|
path = path[k:]
|
|
continue
|
|
}
|
|
|
|
// ... but we can't
|
|
if fixTrailingSlash && len(path) == k+1 {
|
|
return ciPath, true
|
|
}
|
|
return ciPath, false
|
|
}
|
|
|
|
if n.handle != nil {
|
|
return ciPath, true
|
|
} else 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.handle != nil {
|
|
return append(ciPath, '/'), true
|
|
}
|
|
}
|
|
return ciPath, false
|
|
|
|
case catchAll:
|
|
return append(ciPath, path...), true
|
|
|
|
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.handle != 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.handle != nil) ||
|
|
(n.nType == catchAll && n.children[0].handle != nil) {
|
|
return append(ciPath, '/'), true
|
|
}
|
|
return ciPath, false
|
|
}
|
|
}
|
|
}
|
|
return ciPath, false
|
|
}
|
|
}
|
|
|
|
// Nothing found.
|
|
// Try to fix the path by adding / removing a trailing slash
|
|
if fixTrailingSlash {
|
|
if path == "/" {
|
|
return ciPath, true
|
|
}
|
|
if len(loPath)+1 == len(loNPath) && loNPath[len(loPath)] == '/' &&
|
|
loPath[1:] == loNPath[1:len(loPath)] && n.handle != nil {
|
|
return append(ciPath, n.path...), true
|
|
}
|
|
}
|
|
return ciPath, false
|
|
}
|