234 lines
5.0 KiB
Go
234 lines
5.0 KiB
Go
|
package xmlpath
|
||
|
|
|
||
|
|
import (
|
||
|
|
"encoding/xml"
|
||
|
|
"io"
|
||
|
|
)
|
||
|
|
|
||
|
|
// Node is an item in an xml tree that was compiled to
|
||
|
|
// be processed via xml paths. A node may represent:
|
||
|
|
//
|
||
|
|
// - An element in the xml document (<body>)
|
||
|
|
// - An attribute of an element in the xml document (href="...")
|
||
|
|
// - A comment in the xml document (<!--...-->)
|
||
|
|
// - A processing instruction in the xml document (<?...?>)
|
||
|
|
// - Some text within the xml document
|
||
|
|
//
|
||
|
|
type Node struct {
|
||
|
|
kind nodeKind
|
||
|
|
name xml.Name
|
||
|
|
attr string
|
||
|
|
text []byte
|
||
|
|
|
||
|
|
nodes []Node
|
||
|
|
pos int
|
||
|
|
end int
|
||
|
|
|
||
|
|
up *Node
|
||
|
|
down []*Node
|
||
|
|
}
|
||
|
|
|
||
|
|
type nodeKind int
|
||
|
|
|
||
|
|
const (
|
||
|
|
anyNode nodeKind = iota
|
||
|
|
startNode
|
||
|
|
endNode
|
||
|
|
attrNode
|
||
|
|
textNode
|
||
|
|
commentNode
|
||
|
|
procInstNode
|
||
|
|
)
|
||
|
|
|
||
|
|
// String returns the string value of node.
|
||
|
|
//
|
||
|
|
// The string value of a node is:
|
||
|
|
//
|
||
|
|
// - For element nodes, the concatenation of all text nodes within the element.
|
||
|
|
// - For text nodes, the text itself.
|
||
|
|
// - For attribute nodes, the attribute value.
|
||
|
|
// - For comment nodes, the text within the comment delimiters.
|
||
|
|
// - For processing instruction nodes, the content of the instruction.
|
||
|
|
//
|
||
|
|
func (node *Node) String() string {
|
||
|
|
if node.kind == attrNode {
|
||
|
|
return node.attr
|
||
|
|
}
|
||
|
|
return string(node.Bytes())
|
||
|
|
}
|
||
|
|
|
||
|
|
// Bytes returns the string value of node as a byte slice.
|
||
|
|
// See Node.String for a description of what the string value of a node is.
|
||
|
|
func (node *Node) Bytes() []byte {
|
||
|
|
if node.kind == attrNode {
|
||
|
|
return []byte(node.attr)
|
||
|
|
}
|
||
|
|
if node.kind != startNode {
|
||
|
|
return node.text
|
||
|
|
}
|
||
|
|
var text []byte
|
||
|
|
for i := node.pos; i < node.end; i++ {
|
||
|
|
if node.nodes[i].kind == textNode {
|
||
|
|
text = append(text, node.nodes[i].text...)
|
||
|
|
}
|
||
|
|
}
|
||
|
|
return text
|
||
|
|
}
|
||
|
|
|
||
|
|
// equals returns whether the string value of node is equal to s,
|
||
|
|
// without allocating memory.
|
||
|
|
func (node *Node) equals(s string) bool {
|
||
|
|
if node.kind == attrNode {
|
||
|
|
return s == node.attr
|
||
|
|
}
|
||
|
|
if node.kind != startNode {
|
||
|
|
if len(s) != len(node.text) {
|
||
|
|
return false
|
||
|
|
}
|
||
|
|
for i := range s {
|
||
|
|
if s[i] != node.text[i] {
|
||
|
|
return false
|
||
|
|
}
|
||
|
|
}
|
||
|
|
return true
|
||
|
|
}
|
||
|
|
si := 0
|
||
|
|
for i := node.pos; i < node.end; i++ {
|
||
|
|
if node.nodes[i].kind == textNode {
|
||
|
|
for _, c := range node.nodes[i].text {
|
||
|
|
if si > len(s) {
|
||
|
|
return false
|
||
|
|
}
|
||
|
|
if s[si] != c {
|
||
|
|
return false
|
||
|
|
}
|
||
|
|
si++
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
return si == len(s)
|
||
|
|
}
|
||
|
|
|
||
|
|
// Parse reads an xml document from r, parses it, and returns its root node.
|
||
|
|
func Parse(r io.Reader) (*Node, error) {
|
||
|
|
return ParseDecoder(xml.NewDecoder(r))
|
||
|
|
}
|
||
|
|
|
||
|
|
// ParseHTML reads an HTML-like document from r, parses it, and returns
|
||
|
|
// its root node.
|
||
|
|
func ParseHTML(r io.Reader) (*Node, error) {
|
||
|
|
d := xml.NewDecoder(r)
|
||
|
|
d.Strict = false
|
||
|
|
d.AutoClose = xml.HTMLAutoClose
|
||
|
|
d.Entity = xml.HTMLEntity
|
||
|
|
return ParseDecoder(d)
|
||
|
|
}
|
||
|
|
|
||
|
|
// ParseDecoder parses the xml document being decoded by d and returns
|
||
|
|
// its root node.
|
||
|
|
func ParseDecoder(d *xml.Decoder) (*Node, error) {
|
||
|
|
var nodes []Node
|
||
|
|
var text []byte
|
||
|
|
|
||
|
|
// The root node.
|
||
|
|
nodes = append(nodes, Node{kind: startNode})
|
||
|
|
|
||
|
|
for {
|
||
|
|
t, err := d.Token()
|
||
|
|
if err == io.EOF {
|
||
|
|
break
|
||
|
|
}
|
||
|
|
if err != nil {
|
||
|
|
return nil, err
|
||
|
|
}
|
||
|
|
switch t := t.(type) {
|
||
|
|
case xml.EndElement:
|
||
|
|
nodes = append(nodes, Node{
|
||
|
|
kind: endNode,
|
||
|
|
})
|
||
|
|
case xml.StartElement:
|
||
|
|
nodes = append(nodes, Node{
|
||
|
|
kind: startNode,
|
||
|
|
name: t.Name,
|
||
|
|
})
|
||
|
|
for _, attr := range t.Attr {
|
||
|
|
nodes = append(nodes, Node{
|
||
|
|
kind: attrNode,
|
||
|
|
name: attr.Name,
|
||
|
|
attr: attr.Value,
|
||
|
|
})
|
||
|
|
}
|
||
|
|
case xml.CharData:
|
||
|
|
texti := len(text)
|
||
|
|
text = append(text, t...)
|
||
|
|
nodes = append(nodes, Node{
|
||
|
|
kind: textNode,
|
||
|
|
text: text[texti : texti+len(t)],
|
||
|
|
})
|
||
|
|
case xml.Comment:
|
||
|
|
texti := len(text)
|
||
|
|
text = append(text, t...)
|
||
|
|
nodes = append(nodes, Node{
|
||
|
|
kind: commentNode,
|
||
|
|
text: text[texti : texti+len(t)],
|
||
|
|
})
|
||
|
|
case xml.ProcInst:
|
||
|
|
texti := len(text)
|
||
|
|
text = append(text, t.Inst...)
|
||
|
|
nodes = append(nodes, Node{
|
||
|
|
kind: procInstNode,
|
||
|
|
name: xml.Name{Local: t.Target},
|
||
|
|
text: text[texti : texti+len(t.Inst)],
|
||
|
|
})
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// Close the root node.
|
||
|
|
nodes = append(nodes, Node{kind: endNode})
|
||
|
|
|
||
|
|
stack := make([]*Node, 0, len(nodes))
|
||
|
|
downs := make([]*Node, len(nodes))
|
||
|
|
downCount := 0
|
||
|
|
|
||
|
|
for pos := range nodes {
|
||
|
|
|
||
|
|
switch nodes[pos].kind {
|
||
|
|
|
||
|
|
case startNode, attrNode, textNode, commentNode, procInstNode:
|
||
|
|
node := &nodes[pos]
|
||
|
|
node.nodes = nodes
|
||
|
|
node.pos = pos
|
||
|
|
if len(stack) > 0 {
|
||
|
|
node.up = stack[len(stack)-1]
|
||
|
|
}
|
||
|
|
if node.kind == startNode {
|
||
|
|
stack = append(stack, node)
|
||
|
|
} else {
|
||
|
|
node.end = pos + 1
|
||
|
|
}
|
||
|
|
|
||
|
|
case endNode:
|
||
|
|
node := stack[len(stack)-1]
|
||
|
|
node.end = pos
|
||
|
|
stack = stack[:len(stack)-1]
|
||
|
|
|
||
|
|
// Compute downs. Doing that here is what enables the
|
||
|
|
// use of a slice of a contiguous pre-allocated block.
|
||
|
|
node.down = downs[downCount:downCount]
|
||
|
|
for i := node.pos + 1; i < node.end; i++ {
|
||
|
|
if nodes[i].up == node {
|
||
|
|
switch nodes[i].kind {
|
||
|
|
case startNode, textNode, commentNode, procInstNode:
|
||
|
|
node.down = append(node.down, &nodes[i])
|
||
|
|
downCount++
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
if len(stack) == 0 {
|
||
|
|
return node, nil
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
return nil, io.EOF
|
||
|
|
}
|