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// Copyright 2019 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 helpers implements general utility functions that work with
// and on content. The helper functions defined here lay down the
// foundation of how Hugo works with files and filepaths, and perform
// string operations on content.
package helpers
import (
"bytes"
"html/template"
"strings"
"unicode"
"unicode/utf8"
"github.com/gohugoio/hugo/common/loggers"
"github.com/spf13/afero"
"github.com/gohugoio/hugo/markup/converter"
"github.com/gohugoio/hugo/markup"
bp "github.com/gohugoio/hugo/bufferpool"
"github.com/gohugoio/hugo/config"
)
// SummaryDivider denotes where content summarization should end. The default is "<!--more-->".
var SummaryDivider = []byte("<!--more-->")
var (
openingPTag = []byte("<p>")
closingPTag = []byte("</p>")
paragraphIndicator = []byte("<p")
closingIndicator = []byte("</")
)
// ContentSpec provides functionality to render markdown content.
type ContentSpec struct {
Converters markup.ConverterProvider
MardownConverter converter.Converter // Markdown converter with no document context
anchorNameSanitizer converter.AnchorNameSanitizer
// SummaryLength is the length of the summary that Hugo extracts from a content.
summaryLength int
BuildFuture bool
BuildExpired bool
BuildDrafts bool
Cfg config.Provider
}
// NewContentSpec returns a ContentSpec initialized
// with the appropriate fields from the given config.Provider.
func NewContentSpec(cfg config.Provider, logger loggers.Logger, contentFs afero.Fs) (*ContentSpec, error) {
spec := &ContentSpec{
summaryLength: cfg.GetInt("summaryLength"),
BuildFuture: cfg.GetBool("buildFuture"),
BuildExpired: cfg.GetBool("buildExpired"),
BuildDrafts: cfg.GetBool("buildDrafts"),
Cfg: cfg,
}
converterProvider, err := markup.NewConverterProvider(converter.ProviderConfig{
Cfg: cfg,
ContentFs: contentFs,
Logger: logger,
})
if err != nil {
return nil, err
}
spec.Converters = converterProvider
p := converterProvider.Get("markdown")
conv, err := p.New(converter.DocumentContext{})
if err != nil {
return nil, err
}
spec.MardownConverter = conv
if as, ok := conv.(converter.AnchorNameSanitizer); ok {
spec.anchorNameSanitizer = as
} else {
// Use Goldmark's sanitizer
p := converterProvider.Get("goldmark")
conv, err := p.New(converter.DocumentContext{})
if err != nil {
return nil, err
}
spec.anchorNameSanitizer = conv.(converter.AnchorNameSanitizer)
}
return spec, nil
}
var stripHTMLReplacer = strings.NewReplacer("\n", " ", "</p>", "\n", "<br>", "\n", "<br />", "\n")
// StripHTML accepts a string, strips out all HTML tags and returns it.
func StripHTML(s string) string {
// Shortcut strings with no tags in them
if !strings.ContainsAny(s, "<>") {
return s
}
s = stripHTMLReplacer.Replace(s)
// Walk through the string removing all tags
b := bp.GetBuffer()
defer bp.PutBuffer(b)
var inTag, isSpace, wasSpace bool
for _, r := range s {
if !inTag {
isSpace = false
}
switch {
case r == '<':
inTag = true
case r == '>':
inTag = false
case unicode.IsSpace(r):
isSpace = true
fallthrough
default:
if !inTag && (!isSpace || (isSpace && !wasSpace)) {
b.WriteRune(r)
}
}
wasSpace = isSpace
}
return b.String()
}
// stripEmptyNav strips out empty <nav> tags from content.
func stripEmptyNav(in []byte) []byte {
return bytes.Replace(in, []byte("<nav>\n</nav>\n\n"), []byte(``), -1)
}
// BytesToHTML converts bytes to type template.HTML.
func BytesToHTML(b []byte) template.HTML {
return template.HTML(string(b))
}
// ExtractTOC extracts Table of Contents from content.
func ExtractTOC(content []byte) (newcontent []byte, toc []byte) {
if !bytes.Contains(content, []byte("<nav>")) {
return content, nil
}
origContent := make([]byte, len(content))
copy(origContent, content)
first := []byte(`<nav>
<ul>`)
last := []byte(`</ul>
</nav>`)
replacement := []byte(`<nav id="TableOfContents">
<ul>`)
startOfTOC := bytes.Index(content, first)
peekEnd := len(content)
if peekEnd > 70+startOfTOC {
peekEnd = 70 + startOfTOC
}
if startOfTOC < 0 {
return stripEmptyNav(content), toc
}
// Need to peek ahead to see if this nav element is actually the right one.
correctNav := bytes.Index(content[startOfTOC:peekEnd], []byte(`<li><a href="#`))
if correctNav < 0 { // no match found
return content, toc
}
lengthOfTOC := bytes.Index(content[startOfTOC:], last) + len(last)
endOfTOC := startOfTOC + lengthOfTOC
newcontent = append(content[:startOfTOC], content[endOfTOC:]...)
toc = append(replacement, origContent[startOfTOC+len(first):endOfTOC]...)
return
}
func (c *ContentSpec) RenderMarkdown(src []byte) ([]byte, error) {
b, err := c.MardownConverter.Convert(converter.RenderContext{Src: src})
if err != nil {
return nil, err
}
return b.Bytes(), nil
}
func (c *ContentSpec) SanitizeAnchorName(s string) string {
return c.anchorNameSanitizer.SanitizeAnchorName(s)
}
func (c *ContentSpec) ResolveMarkup(in string) string {
in = strings.ToLower(in)
switch in {
case "md", "markdown", "mdown":
return "markdown"
case "html", "htm":
return "html"
default:
if in == "mmark" {
Deprecated("Markup type mmark", "See https://gohugo.io//content-management/formats/#list-of-content-formats", false)
}
if conv := c.Converters.Get(in); conv != nil {
return conv.Name()
}
}
return ""
}
// TotalWords counts instance of one or more consecutive white space
// characters, as defined by unicode.IsSpace, in s.
// This is a cheaper way of word counting than the obvious len(strings.Fields(s)).
func TotalWords(s string) int {
n := 0
inWord := false
for _, r := range s {
wasInWord := inWord
inWord = !unicode.IsSpace(r)
if inWord && !wasInWord {
n++
}
}
return n
}
// TruncateWordsByRune truncates words by runes.
func (c *ContentSpec) TruncateWordsByRune(in []string) (string, bool) {
words := make([]string, len(in))
copy(words, in)
count := 0
for index, word := range words {
if count >= c.summaryLength {
return strings.Join(words[:index], " "), true
}
runeCount := utf8.RuneCountInString(word)
if len(word) == runeCount {
count++
} else if count+runeCount < c.summaryLength {
count += runeCount
} else {
for ri := range word {
if count >= c.summaryLength {
truncatedWords := append(words[:index], word[:ri])
return strings.Join(truncatedWords, " "), true
}
count++
}
}
}
return strings.Join(words, " "), false
}
// TruncateWordsToWholeSentence takes content and truncates to whole sentence
// limited by max number of words. It also returns whether it is truncated.
func (c *ContentSpec) TruncateWordsToWholeSentence(s string) (string, bool) {
var (
wordCount = 0
lastWordIndex = -1
)
for i, r := range s {
if unicode.IsSpace(r) {
wordCount++
lastWordIndex = i
if wordCount >= c.summaryLength {
break
}
}
}
if lastWordIndex == -1 {
return s, false
}
endIndex := -1
for j, r := range s[lastWordIndex:] {
if isEndOfSentence(r) {
endIndex = j + lastWordIndex + utf8.RuneLen(r)
break
}
}
if endIndex == -1 {
return s, false
}
return strings.TrimSpace(s[:endIndex]), endIndex < len(s)
}
// TrimShortHTML removes the <p>/</p> tags from HTML input in the situation
// where said tags are the only <p> tags in the input and enclose the content
// of the input (whitespace excluded).
func (c *ContentSpec) TrimShortHTML(input []byte) []byte {
firstOpeningP := bytes.Index(input, paragraphIndicator)
lastOpeningP := bytes.LastIndex(input, paragraphIndicator)
lastClosingP := bytes.LastIndex(input, closingPTag)
lastClosing := bytes.LastIndex(input, closingIndicator)
if firstOpeningP == lastOpeningP && lastClosingP == lastClosing {
input = bytes.TrimSpace(input)
input = bytes.TrimPrefix(input, openingPTag)
input = bytes.TrimSuffix(input, closingPTag)
input = bytes.TrimSpace(input)
}
return input
}
func isEndOfSentence(r rune) bool {
return r == '.' || r == '?' || r == '!' || r == '"' || r == '\n'
}
// Kept only for benchmark.
func (c *ContentSpec) truncateWordsToWholeSentenceOld(content string) (string, bool) {
words := strings.Fields(content)
if c.summaryLength >= len(words) {
return strings.Join(words, " "), false
}
for counter, word := range words[c.summaryLength:] {
if strings.HasSuffix(word, ".") ||
strings.HasSuffix(word, "?") ||
strings.HasSuffix(word, ".\"") ||
strings.HasSuffix(word, "!") {
upper := c.summaryLength + counter + 1
return strings.Join(words[:upper], " "), (upper < len(words))
}
}
return strings.Join(words[:c.summaryLength], " "), true
}