woodpecker/vendor/github.com/dimfeld/httptreemux/tree.go

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2017-07-31 19:15:05 +00:00
package httptreemux
import (
"fmt"
"net/url"
"strings"
)
type node struct {
path string
priority int
// The list of static children to check.
staticIndices []byte
staticChild []*node
// If none of the above match, check the wildcard children
wildcardChild *node
// If none of the above match, then we use the catch-all, if applicable.
catchAllChild *node
// Data for the node is below.
addSlash bool
isCatchAll bool
// If true, the head handler was set implicitly, so let it also be set explicitly.
implicitHead bool
// If this node is the end of the URL, then call the handler, if applicable.
leafHandler map[string]HandlerFunc
// The names of the parameters to apply.
leafWildcardNames []string
}
func (n *node) sortStaticChild(i int) {
for i > 0 && n.staticChild[i].priority > n.staticChild[i-1].priority {
n.staticChild[i], n.staticChild[i-1] = n.staticChild[i-1], n.staticChild[i]
n.staticIndices[i], n.staticIndices[i-1] = n.staticIndices[i-1], n.staticIndices[i]
i -= 1
}
}
func (n *node) setHandler(verb string, handler HandlerFunc, implicitHead bool) {
if n.leafHandler == nil {
n.leafHandler = make(map[string]HandlerFunc)
}
_, ok := n.leafHandler[verb]
if ok && (verb != "HEAD" || !n.implicitHead) {
panic(fmt.Sprintf("%s already handles %s", n.path, verb))
}
n.leafHandler[verb] = handler
if verb == "HEAD" {
n.implicitHead = implicitHead
}
}
func (n *node) addPath(path string, wildcards []string, inStaticToken bool) *node {
leaf := len(path) == 0
if leaf {
if wildcards != nil {
// Make sure the current wildcards are the same as the old ones.
// If not then we have an ambiguous path.
if n.leafWildcardNames != nil {
if len(n.leafWildcardNames) != len(wildcards) {
// This should never happen.
panic("Reached leaf node with differing wildcard array length. Please report this as a bug.")
}
for i := 0; i < len(wildcards); i++ {
if n.leafWildcardNames[i] != wildcards[i] {
panic(fmt.Sprintf("Wildcards %v are ambiguous with wildcards %v",
n.leafWildcardNames, wildcards))
}
}
} else {
// No wildcards yet, so just add the existing set.
n.leafWildcardNames = wildcards
}
}
return n
}
c := path[0]
nextSlash := strings.Index(path, "/")
var thisToken string
var tokenEnd int
if c == '/' {
// Done processing the previous token, so reset inStaticToken to false.
thisToken = "/"
tokenEnd = 1
} else if nextSlash == -1 {
thisToken = path
tokenEnd = len(path)
} else {
thisToken = path[0:nextSlash]
tokenEnd = nextSlash
}
remainingPath := path[tokenEnd:]
if c == '*' && !inStaticToken {
// Token starts with a *, so it's a catch-all
thisToken = thisToken[1:]
if n.catchAllChild == nil {
n.catchAllChild = &node{path: thisToken, isCatchAll: true}
}
if path[1:] != n.catchAllChild.path {
panic(fmt.Sprintf("Catch-all name in %s doesn't match %s. You probably tried to define overlapping catchalls",
path, n.catchAllChild.path))
}
if nextSlash != -1 {
panic("/ after catch-all found in " + path)
}
if wildcards == nil {
wildcards = []string{thisToken}
} else {
wildcards = append(wildcards, thisToken)
}
n.catchAllChild.leafWildcardNames = wildcards
return n.catchAllChild
} else if c == ':' && !inStaticToken {
// Token starts with a :
thisToken = thisToken[1:]
if wildcards == nil {
wildcards = []string{thisToken}
} else {
wildcards = append(wildcards, thisToken)
}
if n.wildcardChild == nil {
n.wildcardChild = &node{path: "wildcard"}
}
return n.wildcardChild.addPath(remainingPath, wildcards, false)
} else {
// if strings.ContainsAny(thisToken, ":*") {
// panic("* or : in middle of path component " + path)
// }
unescaped := false
if len(thisToken) >= 2 && !inStaticToken {
if thisToken[0] == '\\' && (thisToken[1] == '*' || thisToken[1] == ':' || thisToken[1] == '\\') {
// The token starts with a character escaped by a backslash. Drop the backslash.
c = thisToken[1]
thisToken = thisToken[1:]
unescaped = true
}
}
// Set inStaticToken to ensure that the rest of this token is not mistaken
// for a wildcard if a prefix split occurs at a '*' or ':'.
inStaticToken = (c != '/')
// Do we have an existing node that starts with the same letter?
for i, index := range n.staticIndices {
if c == index {
// Yes. Split it based on the common prefix of the existing
// node and the new one.
child, prefixSplit := n.splitCommonPrefix(i, thisToken)
child.priority++
n.sortStaticChild(i)
if unescaped {
// Account for the removed backslash.
prefixSplit++
}
return child.addPath(path[prefixSplit:], wildcards, inStaticToken)
}
}
// No existing node starting with this letter, so create it.
child := &node{path: thisToken}
if n.staticIndices == nil {
n.staticIndices = []byte{c}
n.staticChild = []*node{child}
} else {
n.staticIndices = append(n.staticIndices, c)
n.staticChild = append(n.staticChild, child)
}
return child.addPath(remainingPath, wildcards, inStaticToken)
}
}
func (n *node) splitCommonPrefix(existingNodeIndex int, path string) (*node, int) {
childNode := n.staticChild[existingNodeIndex]
if strings.HasPrefix(path, childNode.path) {
// No split needs to be done. Rather, the new path shares the entire
// prefix with the existing node, so the new node is just a child of
// the existing one. Or the new path is the same as the existing path,
// which means that we just move on to the next token. Either way,
// this return accomplishes that
return childNode, len(childNode.path)
}
var i int
// Find the length of the common prefix of the child node and the new path.
for i = range childNode.path {
if i == len(path) {
break
}
if path[i] != childNode.path[i] {
break
}
}
commonPrefix := path[0:i]
childNode.path = childNode.path[i:]
// Create a new intermediary node in the place of the existing node, with
// the existing node as a child.
newNode := &node{
path: commonPrefix,
priority: childNode.priority,
// Index is the first letter of the non-common part of the path.
staticIndices: []byte{childNode.path[0]},
staticChild: []*node{childNode},
}
n.staticChild[existingNodeIndex] = newNode
return newNode, i
}
func (n *node) search(method, path string) (found *node, handler HandlerFunc, params []string) {
// if test != nil {
// test.Logf("Searching for %s in %s", path, n.dumpTree("", ""))
// }
pathLen := len(path)
if pathLen == 0 {
if len(n.leafHandler) == 0 {
return nil, nil, nil
} else {
return n, n.leafHandler[method], nil
}
}
// First see if this matches a static token.
firstChar := path[0]
for i, staticIndex := range n.staticIndices {
if staticIndex == firstChar {
child := n.staticChild[i]
childPathLen := len(child.path)
if pathLen >= childPathLen && child.path == path[:childPathLen] {
nextPath := path[childPathLen:]
found, handler, params = child.search(method, nextPath)
}
break
}
}
// If we found a node and it had a valid handler, then return here. Otherwise
// let's remember that we found this one, but look for a better match.
if handler != nil {
return
}
if n.wildcardChild != nil {
// Didn't find a static token, so check for a wildcard.
nextSlash := strings.IndexByte(path, '/')
if nextSlash < 0 {
nextSlash = pathLen
}
thisToken := path[0:nextSlash]
nextToken := path[nextSlash:]
if len(thisToken) > 0 { // Don't match on empty tokens.
wcNode, wcHandler, wcParams := n.wildcardChild.search(method, nextToken)
if wcHandler != nil || (found == nil && wcNode != nil) {
unescaped, err := url.QueryUnescape(thisToken)
if err != nil {
unescaped = thisToken
}
if wcParams == nil {
wcParams = []string{unescaped}
} else {
wcParams = append(wcParams, unescaped)
}
if wcHandler != nil {
return wcNode, wcHandler, wcParams
}
// Didn't actually find a handler here, so remember that we
// found a node but also see if we can fall through to the
// catchall.
found = wcNode
handler = wcHandler
params = wcParams
}
}
}
catchAllChild := n.catchAllChild
if catchAllChild != nil {
// Hit the catchall, so just assign the whole remaining path if it
// has a matching handler.
handler = catchAllChild.leafHandler[method]
// Found a handler, or we found a catchall node without a handler.
// Either way, return it since there's nothing left to check after this.
if handler != nil || found == nil {
unescaped, err := url.QueryUnescape(path)
if err != nil {
unescaped = path
}
return catchAllChild, handler, []string{unescaped}
}
}
return found, handler, params
}
func (n *node) dumpTree(prefix, nodeType string) string {
line := fmt.Sprintf("%s %02d %s%s [%d] %v wildcards %v\n", prefix, n.priority, nodeType, n.path,
len(n.staticChild), n.leafHandler, n.leafWildcardNames)
prefix += " "
for _, node := range n.staticChild {
line += node.dumpTree(prefix, "")
}
if n.wildcardChild != nil {
line += n.wildcardChild.dumpTree(prefix, ":")
}
if n.catchAllChild != nil {
line += n.catchAllChild.dumpTree(prefix, "*")
}
return line
}