// 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 ( "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/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(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") func (h chromaHighlighter) GetIdentity() identity.Identity { return id } type HightlightResult struct { innerLow int innerHigh int highlighted template.HTML } func (h HightlightResult) Wrapped() template.HTML { return h.highlighted } 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 = lexers.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("%s", 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(``, inlineCodeAttrs(lang)) } return `` }, end: func(code bool) string { if code { return `` } 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, `
`, styleAttr)
	fmt.Fprint(w, "")
}

const preEnd = "
" 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(`
") } func writeDivEnd(w hugio.FlexiWriter) { w.WriteString("
") } 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 }