markup: Add blockquote render hooks

Closes gohugoio#12590

hugolib/page__per_output.go

@@ -481,6 +481,8 @@ func (pco *pageContentOutput) initRenderHooks() error {
 				if id != nil {
 					layoutDescriptor.KindVariants = id.(string)
 				}
+			case hooks.BlockquoteRendererType:
+				layoutDescriptor.Kind = "render-blockquote"
 			case hooks.CodeBlockRendererType:
 				layoutDescriptor.Kind = "render-codeblock"
 				if id != nil {

hugolib/site.go

@@ -919,6 +919,10 @@ func (hr hookRendererTemplate) RenderPassthrough(cctx context.Context, w io.Writ
 	return hr.templateHandler.ExecuteWithContext(cctx, hr.templ, w, ctx)
 }
 
+func (hr hookRendererTemplate) RenderBlockquote(cctx context.Context, w hugio.FlexiWriter, ctx hooks.BlockquoteContext) error {
+	return hr.templateHandler.ExecuteWithContext(cctx, hr.templ, w, ctx)
+}
+
 func (hr hookRendererTemplate) ResolvePosition(ctx any) text.Position {
 	return hr.resolvePosition(ctx)
 }

markup/converter/hooks/hooks.go

@@ -78,6 +78,34 @@ type CodeblockContext interface {
 	Ordinal() int
 }
 
+// BlockquoteContext is the context passed to a blockquote render hook.
+type BlockquoteContext interface {
+	AttributesProvider
+	text.Positioner
+	PageProvider
+
+	// Zero-based ordinal for all code blocks in the current document.
+	Ordinal() int
+
+	// The blockquote text.
+	Text() hstring.RenderedString
+
+	// The blockquote text as plain text.
+	PlainText() string
+
+	///  Returns true if the blockquote has an GitHub alert designator.
+	IsAlert() bool
+
+	// The GitHub alert type converted to lowercase, e.g. "note".
+	AlertType() string
+
+	// The blockquote text, excluding the GitHub alert designator.
+	AlertText() hstring.RenderedString
+
+	// The blockquote text, excluding the GitHub alert designator, as plain text.
+	AlertPlainText() string
+}
+
 // PassThroughContext is the context passed to a passthrough render hook.
 type PassthroughContext interface {
 	AttributesProvider
@@ -104,6 +132,10 @@ type CodeBlockRenderer interface {
 	RenderCodeblock(cctx context.Context, w hugio.FlexiWriter, ctx CodeblockContext) error
 }
 
+type BlockquoteRenderer interface {
+	RenderBlockquote(cctx context.Context, w hugio.FlexiWriter, ctx BlockquoteContext) error
+}
+
 type PassthroughRenderer interface {
 	RenderPassthrough(cctx context.Context, w io.Writer, ctx PassthroughContext) error
 }
@@ -161,6 +193,7 @@ const (
 	HeadingRendererType
 	CodeBlockRendererType
 	PassthroughRendererType
+	BlockquoteRendererType
 )
 
 type GetRendererFunc func(t RendererType, id any) any

markup/goldmark/blockquotes/blockquotes.go

@@ -0,0 +1,233 @@
+// Copyright 2024 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 blockquotes
+
+import (
+	"fmt"
+	"regexp"
+	"strings"
+	"sync"
+
+	bp "github.com/gohugoio/hugo/bufferpool"
+
+	"github.com/gohugoio/hugo/common/herrors"
+	htext "github.com/gohugoio/hugo/common/text"
+	"github.com/gohugoio/hugo/common/types/hstring"
+	"github.com/gohugoio/hugo/markup/converter/hooks"
+	"github.com/gohugoio/hugo/markup/goldmark/internal/render"
+	"github.com/gohugoio/hugo/markup/internal/attributes"
+	"github.com/yuin/goldmark"
+	"github.com/yuin/goldmark/ast"
+	"github.com/yuin/goldmark/renderer"
+	"github.com/yuin/goldmark/renderer/html"
+	"github.com/yuin/goldmark/util"
+)
+
+type (
+	blockquotesExtension struct{}
+	htmlRenderer         struct{}
+)
+
+func New() goldmark.Extender {
+	return &blockquotesExtension{}
+}
+
+func (e *blockquotesExtension) Extend(m goldmark.Markdown) {
+	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(ast.KindBlockquote, r.renderBlockquote)
+}
+
+func (r *htmlRenderer) renderBlockquote(w util.BufWriter, src []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	ctx := w.(*render.Context)
+
+	n := node.(*ast.Blockquote)
+
+	renderer := ctx.RenderContext().GetRenderer(hooks.BlockquoteRendererType, nil)
+	if renderer == nil {
+		return r.renderBlockquoteDefault(w, src, n, entering)
+	}
+
+	if entering {
+		first := n.FirstChild()
+		fmt.Println(fmt.Println("===>", string(first.Text(src))))
+		// Store the current pos so we can capture the rendered text.
+		ctx.PushPos(ctx.Buffer.Len())
+		return ast.WalkContinue, nil
+	}
+
+	pos := ctx.PopPos()
+	text := ctx.Buffer.Bytes()[pos:]
+	ctx.Buffer.Truncate(pos)
+
+	ordinal := ctx.GetAndIncrementOrdinal(ast.KindBlockquote)
+
+	plainText := r.blockQuoteToPlainText(n, src)
+
+	bqctx := &blockquoteBlockContext{
+		page:             ctx.DocumentContext().Document,
+		pageInner:        r.getPageInner(ctx),
+		text:             hstring.RenderedString(text),
+		plainText:        plainText,
+		ordinal:          ordinal,
+		AttributesHolder: attributes.New(n.Attributes(), attributes.AttributesOwnerGeneral),
+	}
+
+	bqctx.createPos = func() htext.Position {
+		if resolver, ok := renderer.(hooks.ElementPositionResolver); ok {
+			return resolver.ResolvePosition(bqctx)
+		}
+		return htext.Position{
+			Filename:     ctx.DocumentContext().Filename,
+			LineNumber:   1,
+			ColumnNumber: 1,
+		}
+	}
+
+	cr := renderer.(hooks.BlockquoteRenderer)
+
+	err := cr.RenderBlockquote(
+		ctx.RenderContext().Ctx,
+		w,
+		bqctx,
+	)
+	if err != nil {
+		return ast.WalkContinue, herrors.NewFileErrorFromPos(err, bqctx.createPos())
+	}
+
+	return ast.WalkContinue, nil
+}
+
+func (r *htmlRenderer) getPageInner(rctx *render.Context) any {
+	pid := rctx.PeekPid()
+	if pid > 0 {
+		if lookup := rctx.DocumentContext().DocumentLookup; lookup != nil {
+			if v := rctx.DocumentContext().DocumentLookup(pid); v != nil {
+				return v
+			}
+		}
+	}
+	return rctx.DocumentContext().Document
+}
+
+// Code borrowed from goldmark's html renderer.
+func (r *htmlRenderer) renderBlockquoteDefault(
+	w util.BufWriter, source []byte, n ast.Node, entering bool,
+) (ast.WalkStatus, error) {
+	if entering {
+		if n.Attributes() != nil {
+			_, _ = w.WriteString("<blockquote")
+			html.RenderAttributes(w, n, html.BlockquoteAttributeFilter)
+			_ = w.WriteByte('>')
+		} else {
+			_, _ = w.WriteString("<blockquote>\n")
+		}
+	} else {
+		_, _ = w.WriteString("</blockquote>\n")
+	}
+	return ast.WalkContinue, nil
+}
+
+func (r *htmlRenderer) blockQuoteToPlainText(n *ast.Blockquote, source []byte) string {
+	buf := bp.GetBuffer()
+	defer bp.PutBuffer(buf)
+
+	for c := n.FirstChild(); c != nil; c = c.NextSibling() {
+		buf.Write(c.Text(source))
+	}
+	return buf.String()
+}
+
+type blockquoteBlockContext struct {
+	page      any
+	pageInner any
+	text      hstring.RenderedString
+	plainText string
+	ordinal   int
+
+	// This is only used in error situations and is expensive to create,
+	// so delay creation until needed.
+	pos       htext.Position
+	posInit   sync.Once
+	createPos func() htext.Position
+
+	*attributes.AttributesHolder
+}
+
+func (c *blockquoteBlockContext) Page() any {
+	return c.page
+}
+
+func (c *blockquoteBlockContext) PageInner() any {
+	return c.pageInner
+}
+
+func (c *blockquoteBlockContext) Text() hstring.RenderedString {
+	return c.text
+}
+
+func (c *blockquoteBlockContext) PlainText() string {
+	return c.plainText
+}
+
+func (c *blockquoteBlockContext) IsAlert() bool {
+	panic("not implemented TODO1")
+}
+
+func (c *blockquoteBlockContext) AlertPlainText() string {
+	panic("not implemented TODO1")
+}
+
+func (c *blockquoteBlockContext) AlertText() hstring.RenderedString {
+	panic("not implemented TODO1")
+}
+
+func (c *blockquoteBlockContext) AlertType() string {
+	panic("not implemented TODO1")
+}
+
+func (c *blockquoteBlockContext) Ordinal() int {
+	return c.ordinal
+}
+
+func (c *blockquoteBlockContext) Position() htext.Position {
+	c.posInit.Do(func() {
+		c.pos = c.createPos()
+	})
+	return c.pos
+}
+
+// https://docs.github.com/en/get-started/writing-on-github/getting-started-with-writing-and-formatting-on-github/basic-writing-and-formatting-syntax#alerts
+// Five types:
+// [!NOTE], [!TIP], [!WARNING], [!IMPORTANT], [!CAUTION]
+var gitHubAlertRe = regexp.MustCompile(`^\[!(NOTE|TIP|WARNING|IMPORTANT|CAUTION)\]`)
+
+// resolveGitHubAlert returns one of note, tip, warning, important or caution.
+// An empty string if no match.
+func resolveGitHubAlert(s string) string {
+	m := gitHubAlertRe.FindStringSubmatch(s)
+	if len(m) == 2 {
+		return strings.ToLower(m[1])
+	}
+	return ""
+}

markup/goldmark/blockquotes/blockquotes_integration_test.go

@@ -0,0 +1,46 @@
+// Copyright 2024 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 blockquotes_test
+
+import (
+	"testing"
+
+	"github.com/gohugoio/hugo/hugolib"
+)
+
+func TestBlockquoteHook(t *testing.T) {
+	t.Parallel()
+
+	files := `
+-- config.toml --
+-- layouts/_default/_markup/render-blockquote.html --
+Blockquote: {{ .Text | safeHTML }}|{{ .PlainText }}|
+-- layouts/_default/single.html --
+Content: {{ .Content }}
+-- content/p1.md --
+---
+title: "p1"
+---
+
+> [!NOTE]  
+> Das ist meine Notiz.
+
+`
+
+	b := hugolib.Test(t, files)
+
+	b.AssertFileContent("public/p1/index.html", `
+foo
+`)
+}