mirror of
https://github.com/genuinetools/reg.git
synced 2024-09-11 22:01:02 -04:00
146 lines
3.7 KiB
Go
146 lines
3.7 KiB
Go
// Copyright 2010 The Go Authors. All rights reserved.
|
|
// Use of this source code is governed by a BSD-style
|
|
// license that can be found in the LICENSE file.
|
|
|
|
package html
|
|
|
|
import (
|
|
"fmt"
|
|
)
|
|
|
|
// checkTreeConsistency checks that a node and its descendants are all
|
|
// consistent in their parent/child/sibling relationships.
|
|
func checkTreeConsistency(n *Node) error {
|
|
return checkTreeConsistency1(n, 0)
|
|
}
|
|
|
|
func checkTreeConsistency1(n *Node, depth int) error {
|
|
if depth == 1e4 {
|
|
return fmt.Errorf("html: tree looks like it contains a cycle")
|
|
}
|
|
if err := checkNodeConsistency(n); err != nil {
|
|
return err
|
|
}
|
|
for c := n.FirstChild; c != nil; c = c.NextSibling {
|
|
if err := checkTreeConsistency1(c, depth+1); err != nil {
|
|
return err
|
|
}
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// checkNodeConsistency checks that a node's parent/child/sibling relationships
|
|
// are consistent.
|
|
func checkNodeConsistency(n *Node) error {
|
|
if n == nil {
|
|
return nil
|
|
}
|
|
|
|
nParent := 0
|
|
for p := n.Parent; p != nil; p = p.Parent {
|
|
nParent++
|
|
if nParent == 1e4 {
|
|
return fmt.Errorf("html: parent list looks like an infinite loop")
|
|
}
|
|
}
|
|
|
|
nForward := 0
|
|
for c := n.FirstChild; c != nil; c = c.NextSibling {
|
|
nForward++
|
|
if nForward == 1e6 {
|
|
return fmt.Errorf("html: forward list of children looks like an infinite loop")
|
|
}
|
|
if c.Parent != n {
|
|
return fmt.Errorf("html: inconsistent child/parent relationship")
|
|
}
|
|
}
|
|
|
|
nBackward := 0
|
|
for c := n.LastChild; c != nil; c = c.PrevSibling {
|
|
nBackward++
|
|
if nBackward == 1e6 {
|
|
return fmt.Errorf("html: backward list of children looks like an infinite loop")
|
|
}
|
|
if c.Parent != n {
|
|
return fmt.Errorf("html: inconsistent child/parent relationship")
|
|
}
|
|
}
|
|
|
|
if n.Parent != nil {
|
|
if n.Parent == n {
|
|
return fmt.Errorf("html: inconsistent parent relationship")
|
|
}
|
|
if n.Parent == n.FirstChild {
|
|
return fmt.Errorf("html: inconsistent parent/first relationship")
|
|
}
|
|
if n.Parent == n.LastChild {
|
|
return fmt.Errorf("html: inconsistent parent/last relationship")
|
|
}
|
|
if n.Parent == n.PrevSibling {
|
|
return fmt.Errorf("html: inconsistent parent/prev relationship")
|
|
}
|
|
if n.Parent == n.NextSibling {
|
|
return fmt.Errorf("html: inconsistent parent/next relationship")
|
|
}
|
|
|
|
parentHasNAsAChild := false
|
|
for c := n.Parent.FirstChild; c != nil; c = c.NextSibling {
|
|
if c == n {
|
|
parentHasNAsAChild = true
|
|
break
|
|
}
|
|
}
|
|
if !parentHasNAsAChild {
|
|
return fmt.Errorf("html: inconsistent parent/child relationship")
|
|
}
|
|
}
|
|
|
|
if n.PrevSibling != nil && n.PrevSibling.NextSibling != n {
|
|
return fmt.Errorf("html: inconsistent prev/next relationship")
|
|
}
|
|
if n.NextSibling != nil && n.NextSibling.PrevSibling != n {
|
|
return fmt.Errorf("html: inconsistent next/prev relationship")
|
|
}
|
|
|
|
if (n.FirstChild == nil) != (n.LastChild == nil) {
|
|
return fmt.Errorf("html: inconsistent first/last relationship")
|
|
}
|
|
if n.FirstChild != nil && n.FirstChild == n.LastChild {
|
|
// We have a sole child.
|
|
if n.FirstChild.PrevSibling != nil || n.FirstChild.NextSibling != nil {
|
|
return fmt.Errorf("html: inconsistent sole child's sibling relationship")
|
|
}
|
|
}
|
|
|
|
seen := map[*Node]bool{}
|
|
|
|
var last *Node
|
|
for c := n.FirstChild; c != nil; c = c.NextSibling {
|
|
if seen[c] {
|
|
return fmt.Errorf("html: inconsistent repeated child")
|
|
}
|
|
seen[c] = true
|
|
last = c
|
|
}
|
|
if last != n.LastChild {
|
|
return fmt.Errorf("html: inconsistent last relationship")
|
|
}
|
|
|
|
var first *Node
|
|
for c := n.LastChild; c != nil; c = c.PrevSibling {
|
|
if !seen[c] {
|
|
return fmt.Errorf("html: inconsistent missing child")
|
|
}
|
|
delete(seen, c)
|
|
first = c
|
|
}
|
|
if first != n.FirstChild {
|
|
return fmt.Errorf("html: inconsistent first relationship")
|
|
}
|
|
|
|
if len(seen) != 0 {
|
|
return fmt.Errorf("html: inconsistent forwards/backwards child list")
|
|
}
|
|
|
|
return nil
|
|
}
|