Source: node.go in package golang.org/x/net/html


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

RawNode nodes are not returned by the parser, but can be part of the Node tree passed to func Render to insert raw HTML (without escaping). If so, this package makes no guarantee that the rendered HTML is secure (from e.g. Cross Site Scripting attacks) or well-formed.

	RawNode
	scopeMarkerNode
)

Section 12.2.4.3 says "The markers are inserted when entering applet, object, marquee, template, td, th, and caption elements, and are used to prevent formatting from "leaking" into applet, object, marquee, template, td, th, and caption elements".

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
}

contains returns whether a is within s.

func (s *nodeStack) contains(a atom.Atom) bool {
	for _, n := range *s {
		if n.DataAtom == a && n.Namespace == "" {
			return true
		}
	}
	return false
}

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]
}

type insertionModeStack []insertionMode

func (s *insertionModeStack) pop() (im insertionMode) {
	i := len(*s)
	im = (*s)[i-1]
	*s = (*s)[:i-1]
	return im
}

func (s *insertionModeStack) top() insertionMode {
	if i := len(*s); i > 0 {
		return (*s)[i-1]
	}
	return nil