trout
2016-01-21
Parent:bf38b050b6c4
trout/trie.go
Add Router prefix. Make the Router use a prefix that will be stripped before matching URLs against Endpoints, so we can ignore the prefix that http.Handle is matching against, instead of duplicating it, which can lead to confusing 404s.
1 package trout
3 import (
4 "net/http"
5 "sort"
6 "sync"
7 )
9 type trie struct {
10 branch *branch
11 sync.RWMutex
12 }
14 func (t *trie) match(input []string) ([]int, bool) {
15 if t.branch == nil {
16 t.branch = &branch{}
17 }
18 b := t.branch
19 path := []int{}
20 offset := 0
21 num := len(input)
22 for i := 0; i < num; i++ {
23 // if we're on a nil branch, we're at the end of our line
24 if b == nil {
25 return path, false
26 }
27 offset = pickNextBranch(b, offset, input[i])
28 if offset == -1 {
29 if len(path) == 0 {
30 // can't find it, bail
31 return path, false
32 }
33 // no match, backup
34 path, offset = backup(path)
35 offset = offset + 1 // we want the next index from the previously matched one
36 b = b.parent // we need to be picking a branch from our parent, again
37 i = i - 2 // back up to the choice before the one that got us here
38 } else {
39 path = append(path, offset)
40 b = b.children[offset]
41 offset = 0
42 }
43 }
44 return path, true
45 }
47 type branch struct {
48 parent *branch
49 children []*branch
50 key string
51 isParam bool
52 methods map[string]http.Handler
53 }
55 func (b *branch) Less(i, j int) bool {
56 if b.children[i].key == b.children[j].key {
57 return b.children[j].isParam && !b.children[i].isParam
58 }
59 return b.children[i].key < b.children[j].key
60 }
62 func (b *branch) Len() int {
63 return len(b.children)
64 }
66 func (b *branch) Swap(i, j int) {
67 b.children[i], b.children[j] = b.children[j], b.children[i]
68 }
70 func (b *branch) addChild(key string, param bool) *branch {
71 child := &branch{key: key, parent: b, isParam: param}
72 if b.children == nil {
73 b.children = []*branch{child}
74 return child
75 }
76 b.children = append(b.children, child)
77 sort.Sort(b)
78 return child
79 }
81 func (b *branch) check(input string) bool {
82 if b.isParam && b.key != "" {
83 return true
84 }
85 if b.key == input {
86 return true
87 }
88 return false
89 }
91 func (b *branch) setHandler(method string, handler http.Handler) {
92 if b.methods == nil {
93 b.methods = map[string]http.Handler{}
94 }
95 b.methods[method] = handler
96 }
98 func pickNextBranch(b *branch, offset int, input string) int {
99 count := len(b.children)
100 for i := offset; i < count; i++ {
101 if b.children[i].check(input) {
102 return i
103 }
104 }
105 return -1
106 }
108 func backup(path []int) ([]int, int) {
109 last := len(path) - 1
110 pos := path[last]
111 path = path[:last]
112 return path, pos
113 }