653 lines
16 KiB
Go
653 lines
16 KiB
Go
|
package router
|
||
|
|
||
|
import (
|
||
|
"strings"
|
||
|
"unicode"
|
||
|
"unicode/utf8"
|
||
|
)
|
||
|
|
||
|
func min(a, b int) int {
|
||
|
if a <= b {
|
||
|
return a
|
||
|
}
|
||
|
return b
|
||
|
}
|
||
|
|
||
|
func countParams(path string) uint8 {
|
||
|
var n uint
|
||
|
for i := 0; i < len(path); i++ {
|
||
|
if path[i] != ':' && path[i] != '*' {
|
||
|
continue
|
||
|
}
|
||
|
n++
|
||
|
}
|
||
|
if n >= 255 {
|
||
|
return 255
|
||
|
}
|
||
|
return uint8(n)
|
||
|
}
|
||
|
|
||
|
type nodeType uint8
|
||
|
|
||
|
const (
|
||
|
static nodeType = iota // default
|
||
|
root
|
||
|
param
|
||
|
catchAll
|
||
|
)
|
||
|
|
||
|
type node struct {
|
||
|
path string
|
||
|
wildChild bool
|
||
|
nType nodeType
|
||
|
maxParams uint8
|
||
|
indices string
|
||
|
children []*node
|
||
|
handle Handle
|
||
|
priority uint32
|
||
|
}
|
||
|
|
||
|
// increments priority of the given child and reorders if necessary
|
||
|
func (n *node) incrementChildPrio(pos int) int {
|
||
|
n.children[pos].priority++
|
||
|
prio := n.children[pos].priority
|
||
|
|
||
|
// adjust position (move to front)
|
||
|
newPos := pos
|
||
|
for newPos > 0 && n.children[newPos-1].priority < prio {
|
||
|
// swap node positions
|
||
|
n.children[newPos-1], n.children[newPos] = n.children[newPos], n.children[newPos-1]
|
||
|
|
||
|
newPos--
|
||
|
}
|
||
|
|
||
|
// 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, handle Handle) {
|
||
|
fullPath := path
|
||
|
n.priority++
|
||
|
numParams := countParams(path)
|
||
|
|
||
|
// non-empty tree
|
||
|
if len(n.path) > 0 || len(n.children) > 0 {
|
||
|
walk:
|
||
|
for {
|
||
|
// Update maxParams of the current node
|
||
|
if numParams > n.maxParams {
|
||
|
n.maxParams = numParams
|
||
|
}
|
||
|
|
||
|
// 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 := 0
|
||
|
max := min(len(path), len(n.path))
|
||
|
for i < max && path[i] == n.path[i] {
|
||
|
i++
|
||
|
}
|
||
|
|
||
|
// Split edge
|
||
|
if i < len(n.path) {
|
||
|
child := node{
|
||
|
path: n.path[i:],
|
||
|
wildChild: n.wildChild,
|
||
|
nType: static,
|
||
|
indices: n.indices,
|
||
|
children: n.children,
|
||
|
handle: n.handle,
|
||
|
priority: n.priority - 1,
|
||
|
}
|
||
|
|
||
|
// Update maxParams (max of all children)
|
||
|
for i := range child.children {
|
||
|
if child.children[i].maxParams > child.maxParams {
|
||
|
child.maxParams = child.children[i].maxParams
|
||
|
}
|
||
|
}
|
||
|
|
||
|
n.children = []*node{&child}
|
||
|
// []byte for proper unicode char conversion, see #65
|
||
|
n.indices = string([]byte{n.path[i]})
|
||
|
n.path = path[:i]
|
||
|
n.handle = nil
|
||
|
n.wildChild = false
|
||
|
}
|
||
|
|
||
|
// Make new node a child of this node
|
||
|
if i < len(path) {
|
||
|
path = path[i:]
|
||
|
|
||
|
if n.wildChild {
|
||
|
n = n.children[0]
|
||
|
n.priority++
|
||
|
|
||
|
// Update maxParams of the child node
|
||
|
if numParams > n.maxParams {
|
||
|
n.maxParams = numParams
|
||
|
}
|
||
|
numParams--
|
||
|
|
||
|
// Check if the wildcard matches
|
||
|
if len(path) >= len(n.path) && n.path == path[:len(n.path)] &&
|
||
|
// Check for longer wildcard, e.g. :name and :names
|
||
|
(len(n.path) >= len(path) || path[len(n.path)] == '/') {
|
||
|
continue walk
|
||
|
} else {
|
||
|
// Wildcard conflict
|
||
|
var pathSeg string
|
||
|
if n.nType == catchAll {
|
||
|
pathSeg = path
|
||
|
} else {
|
||
|
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 {
|
||
|
n = n.children[0]
|
||
|
n.priority++
|
||
|
continue walk
|
||
|
}
|
||
|
|
||
|
// Check if a child with the next path byte exists
|
||
|
for i := 0; i < len(n.indices); i++ {
|
||
|
if c == n.indices[i] {
|
||
|
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 += string([]byte{c})
|
||
|
child := &node{
|
||
|
maxParams: numParams,
|
||
|
}
|
||
|
n.children = append(n.children, child)
|
||
|
n.incrementChildPrio(len(n.indices) - 1)
|
||
|
n = child
|
||
|
}
|
||
|
n.insertChild(numParams, path, fullPath, handle)
|
||
|
return
|
||
|
|
||
|
} else if i == len(path) { // Make node a (in-path) leaf
|
||
|
if n.handle != nil {
|
||
|
panic("a handle is already registered for path '" + fullPath + "'")
|
||
|
}
|
||
|
n.handle = handle
|
||
|
}
|
||
|
return
|
||
|
}
|
||
|
} else { // Empty tree
|
||
|
n.insertChild(numParams, path, fullPath, handle)
|
||
|
n.nType = root
|
||
|
}
|
||
|
}
|
||
|
|
||
|
func (n *node) insertChild(numParams uint8, path, fullPath string, handle Handle) {
|
||
|
var offset int // already handled bytes of the path
|
||
|
|
||
|
// find prefix until first wildcard (beginning with ':'' or '*'')
|
||
|
for i, max := 0, len(path); numParams > 0; i++ {
|
||
|
c := path[i]
|
||
|
if c != ':' && c != '*' {
|
||
|
continue
|
||
|
}
|
||
|
|
||
|
// find wildcard end (either '/' or path end)
|
||
|
end := i + 1
|
||
|
for end < max && path[end] != '/' {
|
||
|
switch path[end] {
|
||
|
// the wildcard name must not contain ':' and '*'
|
||
|
case ':', '*':
|
||
|
panic("only one wildcard per path segment is allowed, has: '" +
|
||
|
path[i:] + "' in path '" + fullPath + "'")
|
||
|
default:
|
||
|
end++
|
||
|
}
|
||
|
}
|
||
|
|
||
|
// check if this Node existing children which would be
|
||
|
// unreachable if we insert the wildcard here
|
||
|
if len(n.children) > 0 {
|
||
|
panic("wildcard route '" + path[i:end] +
|
||
|
"' conflicts with existing children in path '" + fullPath + "'")
|
||
|
}
|
||
|
|
||
|
// check if the wildcard has a name
|
||
|
if end-i < 2 {
|
||
|
panic("wildcards must be named with a non-empty name in path '" + fullPath + "'")
|
||
|
}
|
||
|
|
||
|
if c == ':' { // param
|
||
|
// split path at the beginning of the wildcard
|
||
|
if i > 0 {
|
||
|
n.path = path[offset:i]
|
||
|
offset = i
|
||
|
}
|
||
|
|
||
|
child := &node{
|
||
|
nType: param,
|
||
|
maxParams: numParams,
|
||
|
}
|
||
|
n.children = []*node{child}
|
||
|
n.wildChild = true
|
||
|
n = child
|
||
|
n.priority++
|
||
|
numParams--
|
||
|
|
||
|
// if the path doesn't end with the wildcard, then there
|
||
|
// will be another non-wildcard subpath starting with '/'
|
||
|
if end < max {
|
||
|
n.path = path[offset:end]
|
||
|
offset = end
|
||
|
|
||
|
child := &node{
|
||
|
maxParams: numParams,
|
||
|
priority: 1,
|
||
|
}
|
||
|
n.children = []*node{child}
|
||
|
n = child
|
||
|
}
|
||
|
|
||
|
} else { // catchAll
|
||
|
if end != max || numParams > 1 {
|
||
|
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[offset:i]
|
||
|
|
||
|
// first node: catchAll node with empty path
|
||
|
child := &node{
|
||
|
wildChild: true,
|
||
|
nType: catchAll,
|
||
|
maxParams: 1,
|
||
|
}
|
||
|
n.children = []*node{child}
|
||
|
n.indices = string(path[i])
|
||
|
n = child
|
||
|
n.priority++
|
||
|
|
||
|
// second node: node holding the variable
|
||
|
child = &node{
|
||
|
path: path[i:],
|
||
|
nType: catchAll,
|
||
|
maxParams: 1,
|
||
|
handle: handle,
|
||
|
priority: 1,
|
||
|
}
|
||
|
n.children = []*node{child}
|
||
|
|
||
|
return
|
||
|
}
|
||
|
}
|
||
|
|
||
|
// insert remaining path part and handle to the leaf
|
||
|
n.path = path[offset:]
|
||
|
n.handle = handle
|
||
|
}
|
||
|
|
||
|
// 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) (handle Handle, p Params, tsr bool) {
|
||
|
walk: // outer loop for walking the tree
|
||
|
for {
|
||
|
if len(path) > len(n.path) {
|
||
|
if path[:len(n.path)] == n.path {
|
||
|
path = path[len(n.path):]
|
||
|
// 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 {
|
||
|
c := path[0]
|
||
|
for i := 0; i < len(n.indices); i++ {
|
||
|
if c == n.indices[i] {
|
||
|
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.
|
||
|
tsr = (path == "/" && n.handle != 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 p == nil {
|
||
|
// lazy allocation
|
||
|
p = make(Params, 0, n.maxParams)
|
||
|
}
|
||
|
i := len(p)
|
||
|
p = p[:i+1] // expand slice within preallocated capacity
|
||
|
p[i].Key = n.path[1:]
|
||
|
p[i].Value = path[:end]
|
||
|
|
||
|
// 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
|
||
|
tsr = (len(path) == end+1)
|
||
|
return
|
||
|
}
|
||
|
|
||
|
if handle = n.handle; handle != nil {
|
||
|
return
|
||
|
} else 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]
|
||
|
tsr = (n.path == "/" && n.handle != nil)
|
||
|
}
|
||
|
|
||
|
return
|
||
|
|
||
|
case catchAll:
|
||
|
// save param value
|
||
|
if p == nil {
|
||
|
// lazy allocation
|
||
|
p = make(Params, 0, n.maxParams)
|
||
|
}
|
||
|
i := len(p)
|
||
|
p = p[:i+1] // expand slice within preallocated capacity
|
||
|
p[i].Key = n.path[2:]
|
||
|
p[i].Value = path
|
||
|
|
||
|
handle = n.handle
|
||
|
return
|
||
|
|
||
|
default:
|
||
|
panic("invalid node type")
|
||
|
}
|
||
|
}
|
||
|
} else if path == n.path {
|
||
|
// We should have reached the node containing the handle.
|
||
|
// Check if this node has a handle registered.
|
||
|
if handle = n.handle; handle != nil {
|
||
|
return
|
||
|
}
|
||
|
|
||
|
if path == "/" && n.wildChild && n.nType != root {
|
||
|
tsr = true
|
||
|
return
|
||
|
}
|
||
|
|
||
|
// No handle found. Check if a handle for this path + a
|
||
|
// trailing slash exists for trailing slash recommendation
|
||
|
for i := 0; i < len(n.indices); i++ {
|
||
|
if n.indices[i] == '/' {
|
||
|
n = n.children[i]
|
||
|
tsr = (len(n.path) == 1 && n.handle != nil) ||
|
||
|
(n.nType == catchAll && n.children[0].handle != 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
|
||
|
tsr = (path == "/") ||
|
||
|
(len(n.path) == len(path)+1 && n.path[len(path)] == '/' &&
|
||
|
path == n.path[:len(n.path)-1] && n.handle != 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) (ciPath []byte, found bool) {
|
||
|
return n.findCaseInsensitivePathRec(
|
||
|
path,
|
||
|
strings.ToLower(path),
|
||
|
make([]byte, 0, len(path)+1), // preallocate enough memory for new path
|
||
|
[4]byte{}, // empty rune buffer
|
||
|
fixTrailingSlash,
|
||
|
)
|
||
|
}
|
||
|
|
||
|
// 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, loPath string, ciPath []byte, rb [4]byte, fixTrailingSlash bool) ([]byte, bool) {
|
||
|
loNPath := strings.ToLower(n.path)
|
||
|
|
||
|
walk: // outer loop for walking the tree
|
||
|
for len(loPath) >= len(loNPath) && (len(loNPath) == 0 || loPath[1:len(loNPath)] == loNPath[1:]) {
|
||
|
// add common path to result
|
||
|
ciPath = append(ciPath, n.path...)
|
||
|
|
||
|
if path = path[len(n.path):]; len(path) > 0 {
|
||
|
loOld := loPath
|
||
|
loPath = loPath[len(loNPath):]
|
||
|
|
||
|
// 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, len(loNPath))
|
||
|
|
||
|
if rb[0] != 0 {
|
||
|
// old rune not finished
|
||
|
for i := 0; i < len(n.indices); i++ {
|
||
|
if n.indices[i] == rb[0] {
|
||
|
// continue with child node
|
||
|
n = n.children[i]
|
||
|
loNPath = strings.ToLower(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(len(loNPath), 3); off < max; off++ {
|
||
|
if i := len(loNPath) - off; utf8.RuneStart(loOld[i]) {
|
||
|
// read rune from cached lowercase path
|
||
|
rv, _ = utf8.DecodeRuneInString(loOld[i:])
|
||
|
break
|
||
|
}
|
||
|
}
|
||
|
|
||
|
// calculate lowercase bytes of current rune
|
||
|
utf8.EncodeRune(rb[:], rv)
|
||
|
// skipp already processed bytes
|
||
|
rb = shiftNRuneBytes(rb, off)
|
||
|
|
||
|
for i := 0; i < len(n.indices); i++ {
|
||
|
// lowercase matches
|
||
|
if n.indices[i] == rb[0] {
|
||
|
// must use a recursive approach since both the
|
||
|
// uppercase byte and the lowercase byte might exist
|
||
|
// as an index
|
||
|
if out, found := n.children[i].findCaseInsensitivePathRec(
|
||
|
path, loPath, ciPath, rb, fixTrailingSlash,
|
||
|
); found {
|
||
|
return out, true
|
||
|
}
|
||
|
break
|
||
|
}
|
||
|
}
|
||
|
|
||
|
// same for uppercase rune, if it differs
|
||
|
if up := unicode.ToUpper(rv); up != rv {
|
||
|
utf8.EncodeRune(rb[:], up)
|
||
|
rb = shiftNRuneBytes(rb, off)
|
||
|
|
||
|
for i := 0; i < len(n.indices); i++ {
|
||
|
// uppercase matches
|
||
|
if n.indices[i] == rb[0] {
|
||
|
// continue with child node
|
||
|
n = n.children[i]
|
||
|
loNPath = strings.ToLower(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
|
||
|
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
|
||
|
}
|