hugo/markup/goldmark/codeblocks/render.go

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// Copyright 2022 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 codeblocks
import (
"bytes"
"fmt"
"strings"
"sync"
"github.com/gohugoio/hugo/common/herrors"
htext "github.com/gohugoio/hugo/common/text"
"github.com/gohugoio/hugo/markup/converter/hooks"
"github.com/gohugoio/hugo/markup/goldmark/internal/render"
"github.com/gohugoio/hugo/markup/highlight/chromalexers"
"github.com/gohugoio/hugo/markup/internal/attributes"
"github.com/yuin/goldmark"
"github.com/yuin/goldmark/ast"
"github.com/yuin/goldmark/parser"
"github.com/yuin/goldmark/renderer"
"github.com/yuin/goldmark/text"
"github.com/yuin/goldmark/util"
)
type (
codeBlocksExtension struct{}
htmlRenderer struct{}
)
func New() goldmark.Extender {
return &codeBlocksExtension{}
}
func (e *codeBlocksExtension) Extend(m goldmark.Markdown) {
m.Parser().AddOptions(
parser.WithASTTransformers(
util.Prioritized(&Transformer{}, 100),
),
)
m.Renderer().AddOptions(renderer.WithNodeRenderers(
util.Prioritized(newHTMLRenderer(), 100),
))
}
func newHTMLRenderer() renderer.NodeRenderer {
r := &htmlRenderer{}
return r
}
func (r *htmlRenderer) RegisterFuncs(reg renderer.NodeRendererFuncRegisterer) {
reg.Register(KindCodeBlock, r.renderCodeBlock)
}
func (r *htmlRenderer) renderCodeBlock(w util.BufWriter, src []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
ctx := w.(*render.Context)
if entering {
return ast.WalkContinue, nil
}
n := node.(*codeBlock)
lang := getLang(n.b, src)
renderer := ctx.RenderContext().GetRenderer(hooks.CodeBlockRendererType, lang)
if renderer == nil {
return ast.WalkStop, fmt.Errorf("no code renderer found for %q", lang)
}
ordinal := n.ordinal
var buff bytes.Buffer
l := n.b.Lines().Len()
for i := 0; i < l; i++ {
line := n.b.Lines().At(i)
buff.Write(line.Value(src))
}
s := htext.Chomp(buff.String())
var info []byte
if n.b.Info != nil {
info = n.b.Info.Segment.Value(src)
}
attrtp := attributes.AttributesOwnerCodeBlockCustom
if isd, ok := renderer.(hooks.IsDefaultCodeBlockRendererProvider); (ok && isd.IsDefaultCodeBlockRenderer()) || chromalexers.Get(lang) != nil {
// We say that this is a Chroma code block if it's the default code block renderer
// or if the language is supported by Chroma.
attrtp = attributes.AttributesOwnerCodeBlockChroma
}
// IsDefaultCodeBlockRendererProvider
attrs := getAttributes(n.b, info)
cbctx := &codeBlockContext{
page: ctx.DocumentContext().Document,
lang: lang,
code: s,
ordinal: ordinal,
AttributesHolder: attributes.New(attrs, attrtp),
}
cbctx.createPos = func() htext.Position {
if resolver, ok := renderer.(hooks.ElementPositionResolver); ok {
return resolver.ResolvePosition(cbctx)
}
return htext.Position{
Filename: ctx.DocumentContext().Filename,
LineNumber: 1,
ColumnNumber: 1,
}
}
cr := renderer.(hooks.CodeBlockRenderer)
err := cr.RenderCodeblock(
w,
cbctx,
)
ctx.AddIdentity(cr)
if err != nil {
return ast.WalkContinue, herrors.NewFileErrorFromPos(err, cbctx.createPos())
}
return ast.WalkContinue, nil
}
type codeBlockContext struct {
page any
lang string
code string
ordinal int
// This is only used in error situations and is expensive to create,
// to deleay creation until needed.
pos htext.Position
posInit sync.Once
createPos func() htext.Position
*attributes.AttributesHolder
}
func (c *codeBlockContext) Page() any {
return c.page
}
func (c *codeBlockContext) Type() string {
return c.lang
}
func (c *codeBlockContext) Inner() string {
return c.code
}
func (c *codeBlockContext) Ordinal() int {
return c.ordinal
}
func (c *codeBlockContext) Position() htext.Position {
c.posInit.Do(func() {
c.pos = c.createPos()
})
return c.pos
}
func getLang(node *ast.FencedCodeBlock, src []byte) string {
langWithAttributes := string(node.Language(src))
lang, _, _ := strings.Cut(langWithAttributes, "{")
return lang
}
func getAttributes(node *ast.FencedCodeBlock, infostr []byte) []ast.Attribute {
if node.Attributes() != nil {
return node.Attributes()
}
if infostr != nil {
attrStartIdx := -1
for idx, char := range infostr {
if char == '{' {
attrStartIdx = idx
break
}
}
if attrStartIdx != -1 {
n := ast.NewTextBlock() // dummy node for storing attributes
attrStr := infostr[attrStartIdx:]
if attrs, hasAttr := parser.ParseAttributes(text.NewReader(attrStr)); hasAttr {
for _, attr := range attrs {
n.SetAttribute(attr.Name, attr.Value)
}
return n.Attributes()
}
}
}
return nil
}