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- // Copyright 2011 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 (
- "golang.org/x/net/html/atom"
- )
- // A NodeType is the type of a Node.
- type NodeType uint32
- const (
- ErrorNode NodeType = iota
- TextNode
- DocumentNode
- ElementNode
- CommentNode
- DoctypeNode
- scopeMarkerNode
- )
- // Section 12.2.3.3 says "scope markers are inserted when entering applet
- // elements, buttons, object elements, marquees, table cells, and table
- // captions, and are used to prevent formatting from 'leaking'".
- var scopeMarker = Node{Type: scopeMarkerNode}
- // A Node consists of a NodeType and some Data (tag name for element nodes,
- // content for text) and are part of a tree of Nodes. Element nodes may also
- // have a Namespace and contain a slice of Attributes. Data is unescaped, so
- // that it looks like "a<b" rather than "a<b". For element nodes, DataAtom
- // is the atom for Data, or zero if Data is not a known tag name.
- //
- // An empty Namespace implies a "http://www.w3.org/1999/xhtml" namespace.
- // Similarly, "math" is short for "http://www.w3.org/1998/Math/MathML", and
- // "svg" is short for "http://www.w3.org/2000/svg".
- type Node struct {
- Parent, FirstChild, LastChild, PrevSibling, NextSibling *Node
- Type NodeType
- DataAtom atom.Atom
- Data string
- Namespace string
- Attr []Attribute
- }
- // InsertBefore inserts newChild as a child of n, immediately before oldChild
- // in the sequence of n's children. oldChild may be nil, in which case newChild
- // is appended to the end of n's children.
- //
- // It will panic if newChild already has a parent or siblings.
- func (n *Node) InsertBefore(newChild, oldChild *Node) {
- if newChild.Parent != nil || newChild.PrevSibling != nil || newChild.NextSibling != nil {
- panic("html: InsertBefore called for an attached child Node")
- }
- var prev, next *Node
- if oldChild != nil {
- prev, next = oldChild.PrevSibling, oldChild
- } else {
- prev = n.LastChild
- }
- if prev != nil {
- prev.NextSibling = newChild
- } else {
- n.FirstChild = newChild
- }
- if next != nil {
- next.PrevSibling = newChild
- } else {
- n.LastChild = newChild
- }
- newChild.Parent = n
- newChild.PrevSibling = prev
- newChild.NextSibling = next
- }
- // AppendChild adds a node c as a child of n.
- //
- // It will panic if c already has a parent or siblings.
- func (n *Node) AppendChild(c *Node) {
- if c.Parent != nil || c.PrevSibling != nil || c.NextSibling != nil {
- panic("html: AppendChild called for an attached child Node")
- }
- last := n.LastChild
- if last != nil {
- last.NextSibling = c
- } else {
- n.FirstChild = c
- }
- n.LastChild = c
- c.Parent = n
- c.PrevSibling = last
- }
- // RemoveChild removes a node c that is a child of n. Afterwards, c will have
- // no parent and no siblings.
- //
- // It will panic if c's parent is not n.
- func (n *Node) RemoveChild(c *Node) {
- if c.Parent != n {
- panic("html: RemoveChild called for a non-child Node")
- }
- if n.FirstChild == c {
- n.FirstChild = c.NextSibling
- }
- if c.NextSibling != nil {
- c.NextSibling.PrevSibling = c.PrevSibling
- }
- if n.LastChild == c {
- n.LastChild = c.PrevSibling
- }
- if c.PrevSibling != nil {
- c.PrevSibling.NextSibling = c.NextSibling
- }
- c.Parent = nil
- c.PrevSibling = nil
- c.NextSibling = nil
- }
- // reparentChildren reparents all of src's child nodes to dst.
- func reparentChildren(dst, src *Node) {
- for {
- child := src.FirstChild
- if child == nil {
- break
- }
- src.RemoveChild(child)
- dst.AppendChild(child)
- }
- }
- // clone returns a new node with the same type, data and attributes.
- // The clone has no parent, no siblings and no children.
- func (n *Node) clone() *Node {
- m := &Node{
- Type: n.Type,
- DataAtom: n.DataAtom,
- Data: n.Data,
- Attr: make([]Attribute, len(n.Attr)),
- }
- copy(m.Attr, n.Attr)
- return m
- }
- // nodeStack is a stack of nodes.
- type nodeStack []*Node
- // pop pops the stack. It will panic if s is empty.
- func (s *nodeStack) pop() *Node {
- i := len(*s)
- n := (*s)[i-1]
- *s = (*s)[:i-1]
- return n
- }
- // top returns the most recently pushed node, or nil if s is empty.
- func (s *nodeStack) top() *Node {
- if i := len(*s); i > 0 {
- return (*s)[i-1]
- }
- return nil
- }
- // index returns the index of the top-most occurrence of n in the stack, or -1
- // if n is not present.
- func (s *nodeStack) index(n *Node) int {
- for i := len(*s) - 1; i >= 0; i-- {
- if (*s)[i] == n {
- return i
- }
- }
- return -1
- }
- // insert inserts a node at the given index.
- func (s *nodeStack) insert(i int, n *Node) {
- (*s) = append(*s, nil)
- copy((*s)[i+1:], (*s)[i:])
- (*s)[i] = n
- }
- // remove removes a node from the stack. It is a no-op if n is not present.
- func (s *nodeStack) remove(n *Node) {
- i := s.index(n)
- if i == -1 {
- return
- }
- copy((*s)[i:], (*s)[i+1:])
- j := len(*s) - 1
- (*s)[j] = nil
- *s = (*s)[:j]
- }
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