ref: 30748decf10526d4df5bbf16059cdf9bf76250f9
dir: /publisher/htmlElementsCollector.go/
// Copyright 2020 The Hugo Authors. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package publisher
import (
"github.com/gohugoio/hugo/helpers"
"golang.org/x/net/html"
yaml "gopkg.in/yaml.v2"
"bytes"
"sort"
"strings"
"sync"
)
func newHTMLElementsCollector() *htmlElementsCollector {
return &htmlElementsCollector{
elementSet: make(map[string]bool),
}
}
func newHTMLElementsCollectorWriter(collector *htmlElementsCollector) *cssClassCollectorWriter {
return &cssClassCollectorWriter{
collector: collector,
}
}
// HTMLElements holds lists of tags and attribute values for classes and id.
type HTMLElements struct {
Tags []string `json:"tags"`
Classes []string `json:"classes"`
IDs []string `json:"ids"`
}
func (h *HTMLElements) Merge(other HTMLElements) {
h.Tags = append(h.Tags, other.Tags...)
h.Classes = append(h.Classes, other.Classes...)
h.IDs = append(h.IDs, other.IDs...)
h.Tags = helpers.UniqueStringsReuse(h.Tags)
h.Classes = helpers.UniqueStringsReuse(h.Classes)
h.IDs = helpers.UniqueStringsReuse(h.IDs)
}
func (h *HTMLElements) Sort() {
sort.Strings(h.Tags)
sort.Strings(h.Classes)
sort.Strings(h.IDs)
}
type cssClassCollectorWriter struct {
collector *htmlElementsCollector
buff bytes.Buffer
isCollecting bool
dropValue bool
inQuote bool
}
func (w *cssClassCollectorWriter) Write(p []byte) (n int, err error) {
n = len(p)
i := 0
for i < len(p) {
if !w.isCollecting {
for ; i < len(p); i++ {
b := p[i]
if b == '<' {
w.startCollecting()
break
}
}
}
if w.isCollecting {
for ; i < len(p); i++ {
b := p[i]
if !w.inQuote && b == '/' {
// End element, we don't care about those.
w.endCollecting(true)
break
}
w.toggleIfQuote(b)
if !w.inQuote && b == '>' {
w.endCollecting(false)
break
}
w.buff.WriteByte(b)
}
if !w.isCollecting {
if w.dropValue {
w.buff.Reset()
} else {
// First check if we have processed this element before.
w.collector.mu.RLock()
// See https://github.com/dominikh/go-tools/issues/723
//lint:ignore S1030 This construct avoids memory allocation for the string.
seen := w.collector.elementSet[string(w.buff.Bytes())]
w.collector.mu.RUnlock()
if seen {
w.buff.Reset()
continue
}
s := w.buff.String()
w.buff.Reset()
el := parseHTMLElement(s)
w.collector.mu.Lock()
w.collector.elementSet[s] = true
if el.Tag != "" {
w.collector.elements = append(w.collector.elements, el)
}
w.collector.mu.Unlock()
}
}
}
}
return
}
func (c *cssClassCollectorWriter) endCollecting(drop bool) {
c.isCollecting = false
c.inQuote = false
c.dropValue = drop
}
func (c *cssClassCollectorWriter) startCollecting() {
c.isCollecting = true
c.dropValue = false
}
func (c *cssClassCollectorWriter) toggleIfQuote(b byte) {
if isQuote(b) {
c.inQuote = !c.inQuote
}
}
type htmlElement struct {
Tag string
Classes []string
IDs []string
}
type htmlElementsCollector struct {
// Contains the raw HTML string. We will get the same element
// several times, and want to avoid costly reparsing when this
// is used for aggregated data only.
elementSet map[string]bool
elements []htmlElement
mu sync.RWMutex
}
func (c *htmlElementsCollector) getHTMLElements() HTMLElements {
var (
classes []string
ids []string
tags []string
)
for _, el := range c.elements {
classes = append(classes, el.Classes...)
ids = append(ids, el.IDs...)
tags = append(tags, el.Tag)
}
classes = helpers.UniqueStringsSorted(classes)
ids = helpers.UniqueStringsSorted(ids)
tags = helpers.UniqueStringsSorted(tags)
els := HTMLElements{
Classes: classes,
IDs: ids,
Tags: tags,
}
return els
}
func isQuote(b byte) bool {
return b == '"' || b == '\''
}
var htmlJsonFixer = strings.NewReplacer(", ", "\n")
func parseHTMLElement(elStr string) (el htmlElement) {
elStr = strings.TrimSpace(elStr)
if !strings.HasSuffix(elStr, ">") {
elStr += ">"
}
n, err := html.Parse(strings.NewReader(elStr))
if err != nil {
return
}
var walk func(*html.Node)
walk = func(n *html.Node) {
if n.Type == html.ElementNode && strings.Contains(elStr, n.Data) {
el.Tag = n.Data
for _, a := range n.Attr {
switch {
case strings.EqualFold(a.Key, "id"):
// There should be only one, but one never knows...
el.IDs = append(el.IDs, a.Val)
default:
if strings.EqualFold(a.Key, "class") {
el.Classes = append(el.Classes, strings.Fields(a.Val)...)
} else {
key := strings.ToLower(a.Key)
val := strings.TrimSpace(a.Val)
if strings.Contains(key, "class") && strings.HasPrefix(val, "{") {
// This looks like a Vue or AlpineJS class binding.
// Try to unmarshal it as YAML and pull the keys.
// This may look odd, as the source is (probably) JS (JSON), but the YAML
// parser is much more lenient with simple JS input, it seems.
m := make(map[string]interface{})
val = htmlJsonFixer.Replace(strings.Trim(val, "{}"))
// Remove leading space to make it look like YAML.
lines := strings.Split(val, "\n")
for i, l := range lines {
lines[i] = strings.TrimSpace(l)
}
val = strings.Join(lines, "\n")
err := yaml.Unmarshal([]byte(val), &m)
if err == nil {
for k := range m {
el.Classes = append(el.Classes, strings.Fields(k)...)
}
} else {
// Just insert the raw values. This is used for CSS class pruning
// so, it's important not to leave out values that may be a CSS class.
el.Classes = append(el.Classes, strings.Fields(val)...)
}
}
}
}
}
}
for c := n.FirstChild; c != nil; c = c.NextSibling {
walk(c)
}
}
walk(n)
return
}