hugo/markup/highlight/highlight.go
2023-05-18 21:25:27 +02:00

370 lines
8.6 KiB
Go

// 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 highlight
import (
"context"
"fmt"
gohtml "html"
"html/template"
"io"
"strings"
"github.com/alecthomas/chroma/v2"
"github.com/alecthomas/chroma/v2/formatters/html"
"github.com/alecthomas/chroma/v2/lexers"
"github.com/alecthomas/chroma/v2/styles"
"github.com/gohugoio/hugo/common/hugio"
"github.com/gohugoio/hugo/common/text"
"github.com/gohugoio/hugo/identity"
"github.com/gohugoio/hugo/markup/converter/hooks"
"github.com/gohugoio/hugo/markup/highlight/chromalexers"
"github.com/gohugoio/hugo/markup/internal/attributes"
)
// Markdown attributes used by the Chroma hightlighter.
var chromaHightlightProcessingAttributes = map[string]bool{
"anchorLineNos": true,
"guessSyntax": true,
"hl_Lines": true,
"lineAnchors": true,
"lineNos": true,
"lineNoStart": true,
"lineNumbersInTable": true,
"noClasses": true,
"style": true,
"tabWidth": true,
}
func init() {
for k, v := range chromaHightlightProcessingAttributes {
chromaHightlightProcessingAttributes[strings.ToLower(k)] = v
}
}
func New(cfg Config) Highlighter {
return chromaHighlighter{
cfg: cfg,
}
}
type Highlighter interface {
Highlight(code, lang string, opts any) (string, error)
HighlightCodeBlock(ctx hooks.CodeblockContext, opts any) (HightlightResult, error)
hooks.CodeBlockRenderer
hooks.IsDefaultCodeBlockRendererProvider
}
type chromaHighlighter struct {
cfg Config
}
func (h chromaHighlighter) Highlight(code, lang string, opts any) (string, error) {
cfg := h.cfg
if err := applyOptions(opts, &cfg); err != nil {
return "", err
}
var b strings.Builder
if _, _, err := highlight(&b, code, lang, nil, cfg); err != nil {
return "", err
}
return b.String(), nil
}
func (h chromaHighlighter) HighlightCodeBlock(ctx hooks.CodeblockContext, opts any) (HightlightResult, error) {
cfg := h.cfg
var b strings.Builder
attributes := ctx.(hooks.AttributesOptionsSliceProvider).AttributesSlice()
options := ctx.Options()
if err := applyOptionsFromMap(options, &cfg); err != nil {
return HightlightResult{}, err
}
// Apply these last so the user can override them.
if err := applyOptions(opts, &cfg); err != nil {
return HightlightResult{}, err
}
if err := applyOptionsFromCodeBlockContext(ctx, &cfg); err != nil {
return HightlightResult{}, err
}
low, high, err := highlight(&b, ctx.Inner(), ctx.Type(), attributes, cfg)
if err != nil {
return HightlightResult{}, err
}
highlighted := b.String()
if high == 0 {
high = len(highlighted)
}
return HightlightResult{
highlighted: template.HTML(highlighted),
innerLow: low,
innerHigh: high,
}, nil
}
func (h chromaHighlighter) RenderCodeblock(cctx context.Context, w hugio.FlexiWriter, ctx hooks.CodeblockContext) error {
cfg := h.cfg
attributes := ctx.(hooks.AttributesOptionsSliceProvider).AttributesSlice()
if err := applyOptionsFromMap(ctx.Options(), &cfg); err != nil {
return err
}
if err := applyOptionsFromCodeBlockContext(ctx, &cfg); err != nil {
return err
}
code := text.Puts(ctx.Inner())
_, _, err := highlight(w, code, ctx.Type(), attributes, cfg)
return err
}
func (h chromaHighlighter) IsDefaultCodeBlockRenderer() bool {
return true
}
var id = identity.NewPathIdentity("chroma", "highlight")
// GetIdentity is for internal use.
func (h chromaHighlighter) GetIdentity() identity.Identity {
return id
}
// HightlightResult holds the result of an highlighting operation.
type HightlightResult struct {
innerLow int
innerHigh int
highlighted template.HTML
}
// Wrapped returns the highlighted code wrapped in a <div>, <pre> and <code> tag.
func (h HightlightResult) Wrapped() template.HTML {
return h.highlighted
}
// Inner returns the highlighted code without the wrapping <div>, <pre> and <code> tag, suitable for inline use.
func (h HightlightResult) Inner() template.HTML {
return h.highlighted[h.innerLow:h.innerHigh]
}
func highlight(fw hugio.FlexiWriter, code, lang string, attributes []attributes.Attribute, cfg Config) (int, int, error) {
var lexer chroma.Lexer
if lang != "" {
lexer = chromalexers.Get(lang)
}
if lexer == nil && (cfg.GuessSyntax && !cfg.NoHl) {
lexer = lexers.Analyse(code)
if lexer == nil {
lexer = lexers.Fallback
}
lang = strings.ToLower(lexer.Config().Name)
}
w := &byteCountFlexiWriter{delegate: fw}
if lexer == nil {
if cfg.Hl_inline {
fmt.Fprint(w, fmt.Sprintf("<code%s>%s</code>", inlineCodeAttrs(lang), gohtml.EscapeString(code)))
} else {
preWrapper := getPreWrapper(lang, w)
fmt.Fprint(w, preWrapper.Start(true, ""))
fmt.Fprint(w, gohtml.EscapeString(code))
fmt.Fprint(w, preWrapper.End(true))
}
return 0, 0, nil
}
style := styles.Get(cfg.Style)
if style == nil {
style = styles.Fallback
}
lexer = chroma.Coalesce(lexer)
iterator, err := lexer.Tokenise(nil, code)
if err != nil {
return 0, 0, err
}
if !cfg.Hl_inline {
writeDivStart(w, attributes)
}
options := cfg.toHTMLOptions()
var wrapper html.PreWrapper
if cfg.Hl_inline {
wrapper = startEnd{
start: func(code bool, styleAttr string) string {
if code {
return fmt.Sprintf(`<code%s>`, inlineCodeAttrs(lang))
}
return ``
},
end: func(code bool) string {
if code {
return `</code>`
}
return ``
},
}
} else {
wrapper = getPreWrapper(lang, w)
}
options = append(options, html.WithPreWrapper(wrapper))
formatter := html.New(options...)
if err := formatter.Format(w, style, iterator); err != nil {
return 0, 0, err
}
if !cfg.Hl_inline {
writeDivEnd(w)
}
if p, ok := wrapper.(*preWrapper); ok {
return p.low, p.high, nil
}
return 0, 0, nil
}
func getPreWrapper(language string, writeCounter *byteCountFlexiWriter) *preWrapper {
return &preWrapper{language: language, writeCounter: writeCounter}
}
type preWrapper struct {
low int
high int
writeCounter *byteCountFlexiWriter
language string
}
func (p *preWrapper) Start(code bool, styleAttr string) string {
var language string
if code {
language = p.language
}
w := &strings.Builder{}
WritePreStart(w, language, styleAttr)
p.low = p.writeCounter.counter + w.Len()
return w.String()
}
func inlineCodeAttrs(lang string) string {
if lang == "" {
}
return fmt.Sprintf(` class="code-inline language-%s"`, lang)
}
func WritePreStart(w io.Writer, language, styleAttr string) {
fmt.Fprintf(w, `<pre tabindex="0"%s>`, styleAttr)
fmt.Fprint(w, "<code")
if language != "" {
fmt.Fprint(w, ` class="language-`+language+`"`)
fmt.Fprint(w, ` data-lang="`+language+`"`)
}
fmt.Fprint(w, ">")
}
const preEnd = "</code></pre>"
func (p *preWrapper) End(code bool) string {
p.high = p.writeCounter.counter
return preEnd
}
type startEnd struct {
start func(code bool, styleAttr string) string
end func(code bool) string
}
func (s startEnd) Start(code bool, styleAttr string) string {
return s.start(code, styleAttr)
}
func (s startEnd) End(code bool) string {
return s.end(code)
}
func WritePreEnd(w io.Writer) {
fmt.Fprint(w, preEnd)
}
func writeDivStart(w hugio.FlexiWriter, attrs []attributes.Attribute) {
w.WriteString(`<div class="highlight`)
if attrs != nil {
for _, attr := range attrs {
if attr.Name == "class" {
w.WriteString(" " + attr.ValueString())
break
}
}
_, _ = w.WriteString("\"")
attributes.RenderAttributes(w, true, attrs...)
} else {
_, _ = w.WriteString("\"")
}
w.WriteString(">")
}
func writeDivEnd(w hugio.FlexiWriter) {
w.WriteString("</div>")
}
type byteCountFlexiWriter struct {
delegate hugio.FlexiWriter
counter int
}
func (w *byteCountFlexiWriter) Write(p []byte) (int, error) {
n, err := w.delegate.Write(p)
w.counter += n
return n, err
}
func (w *byteCountFlexiWriter) WriteByte(c byte) error {
w.counter++
return w.delegate.WriteByte(c)
}
func (w *byteCountFlexiWriter) WriteString(s string) (int, error) {
n, err := w.delegate.WriteString(s)
w.counter += n
return n, err
}
func (w *byteCountFlexiWriter) WriteRune(r rune) (int, error) {
n, err := w.delegate.WriteRune(r)
w.counter += n
return n, err
}