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5dccaa1 Aug 28, 2016
@mna @matrixik
162 lines (144 sloc) 4.62 KB
package goquery
import (
"bytes"
"golang.org/x/net/html"
)
// used to determine if a set (map[*html.Node]bool) should be used
// instead of iterating over a slice. The set uses more memory and
// is slower than slice iteration for small N.
const minNodesForSet = 1000
var nodeNames = []string{
html.ErrorNode: "#error",
html.TextNode: "#text",
html.DocumentNode: "#document",
html.CommentNode: "#comment",
}
// NodeName returns the node name of the first element in the selection.
// It tries to behave in a similar way as the DOM's nodeName property
// (https://developer.mozilla.org/en-US/docs/Web/API/Node/nodeName).
//
// Go's net/html package defines the following node types, listed with
// the corresponding returned value from this function:
//
// ErrorNode : #error
// TextNode : #text
// DocumentNode : #document
// ElementNode : the element's tag name
// CommentNode : #comment
// DoctypeNode : the name of the document type
//
func NodeName(s *Selection) string {
if s.Length() == 0 {
return ""
}
switch n := s.Get(0); n.Type {
case html.ElementNode, html.DoctypeNode:
return n.Data
default:
if n.Type >= 0 && int(n.Type) < len(nodeNames) {
return nodeNames[n.Type]
}
return ""
}
}
// OuterHtml returns the outer HTML rendering of the first item in
// the selection - that is, the HTML including the first element's
// tag and attributes.
//
// Unlike InnerHtml, this is a function and not a method on the Selection,
// because this is not a jQuery method (in javascript-land, this is
// a property provided by the DOM).
func OuterHtml(s *Selection) (string, error) {
var buf bytes.Buffer
if s.Length() == 0 {
return "", nil
}
n := s.Get(0)
if err := html.Render(&buf, n); err != nil {
return "", err
}
return buf.String(), nil
}
// Loop through all container nodes to search for the target node.
func sliceContains(container []*html.Node, contained *html.Node) bool {
for _, n := range container {
if nodeContains(n, contained) {
return true
}
}
return false
}
// Checks if the contained node is within the container node.
func nodeContains(container *html.Node, contained *html.Node) bool {
// Check if the parent of the contained node is the container node, traversing
// upward until the top is reached, or the container is found.
for contained = contained.Parent; contained != nil; contained = contained.Parent {
if container == contained {
return true
}
}
return false
}
// Checks if the target node is in the slice of nodes.
func isInSlice(slice []*html.Node, node *html.Node) bool {
return indexInSlice(slice, node) > -1
}
// Returns the index of the target node in the slice, or -1.
func indexInSlice(slice []*html.Node, node *html.Node) int {
if node != nil {
for i, n := range slice {
if n == node {
return i
}
}
}
return -1
}
// Appends the new nodes to the target slice, making sure no duplicate is added.
// There is no check to the original state of the target slice, so it may still
// contain duplicates. The target slice is returned because append() may create
// a new underlying array. If targetSet is nil, a local set is created with the
// target if len(target) + len(nodes) is greater than minNodesForSet.
func appendWithoutDuplicates(target []*html.Node, nodes []*html.Node, targetSet map[*html.Node]bool) []*html.Node {
// if there are not that many nodes, don't use the map, faster to just use nested loops
// (unless a non-nil targetSet is passed, in which case the caller knows better).
if targetSet == nil && len(target)+len(nodes) < minNodesForSet {
for _, n := range nodes {
if !isInSlice(target, n) {
target = append(target, n)
}
}
return target
}
// if a targetSet is passed, then assume it is reliable, otherwise create one
// and initialize it with the current target contents.
if targetSet == nil {
targetSet = make(map[*html.Node]bool, len(target))
for _, n := range target {
targetSet[n] = true
}
}
for _, n := range nodes {
if !targetSet[n] {
target = append(target, n)
targetSet[n] = true
}
}
return target
}
// Loop through a selection, returning only those nodes that pass the predicate
// function.
func grep(sel *Selection, predicate func(i int, s *Selection) bool) (result []*html.Node) {
for i, n := range sel.Nodes {
if predicate(i, newSingleSelection(n, sel.document)) {
result = append(result, n)
}
}
return result
}
// Creates a new Selection object based on the specified nodes, and keeps the
// source Selection object on the stack (linked list).
func pushStack(fromSel *Selection, nodes []*html.Node) *Selection {
result := &Selection{nodes, fromSel.document, fromSel}
return result
}