markup/goldmark: Support auto links in render hook

Fixes #8755

markup/goldmark/render_hooks.go

@@ -15,6 +15,7 @@ package goldmark
 
 import (
 	"bytes"
+	"strings"
 	"sync"
 
 	"github.com/spf13/cast"
@@ -134,6 +135,7 @@ func (r *hookedRenderer) SetOption(name renderer.OptionName, value interface{})
 // RegisterFuncs implements NodeRenderer.RegisterFuncs.
 func (r *hookedRenderer) RegisterFuncs(reg renderer.NodeRendererFuncRegisterer) {
 	reg.Register(ast.KindLink, r.renderLink)
+	reg.Register(ast.KindAutoLink, r.renderAutoLink)
 	reg.Register(ast.KindImage, r.renderImage)
 	reg.Register(ast.KindHeading, r.renderHeading)
 }
@@ -307,6 +309,74 @@ func (r *hookedRenderer) renderLink(w util.BufWriter, source []byte, node ast.No
 	return ast.WalkContinue, err
 }
 
+func (r *hookedRenderer) renderAutoLink(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	if !entering {
+		return ast.WalkContinue, nil
+	}
+
+	n := node.(*ast.AutoLink)
+	var h hooks.Renderers
+
+	ctx, ok := w.(*renderContext)
+	if ok {
+		h = ctx.RenderContext().RenderHooks
+		ok = h.LinkRenderer != nil
+	}
+
+	if !ok {
+		return r.renderDefaultAutoLink(w, source, node, entering)
+	}
+
+	url := string(n.URL(source))
+	label := string(n.Label(source))
+	if n.AutoLinkType == ast.AutoLinkEmail && !strings.HasPrefix(strings.ToLower(url), "mailto:") {
+		url = "mailto:" + url
+	}
+
+	err := h.LinkRenderer.RenderLink(
+		w,
+		linkContext{
+			page:        ctx.DocumentContext().Document,
+			destination: url,
+			text:        label,
+			plainText:   label,
+		},
+	)
+
+	// TODO(bep) I have a working branch that fixes these rather confusing identity types,
+	// but for now it's important that it's not .GetIdentity() that's added here,
+	// to make sure we search the entire chain on changes.
+	ctx.AddIdentity(h.LinkRenderer)
+
+	return ast.WalkContinue, err
+}
+
+// Fall back to the default Goldmark render funcs. Method below borrowed from:
+// https://github.com/yuin/goldmark/blob/5588d92a56fe1642791cf4aa8e9eae8227cfeecd/renderer/html/html.go#L439
+func (r *hookedRenderer) renderDefaultAutoLink(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	n := node.(*ast.AutoLink)
+	if !entering {
+		return ast.WalkContinue, nil
+	}
+	_, _ = w.WriteString(`<a href="`)
+	url := n.URL(source)
+	label := n.Label(source)
+	if n.AutoLinkType == ast.AutoLinkEmail && !bytes.HasPrefix(bytes.ToLower(url), []byte("mailto:")) {
+		_, _ = w.WriteString("mailto:")
+	}
+	_, _ = w.Write(util.EscapeHTML(util.URLEscape(url, false)))
+	if n.Attributes() != nil {
+		_ = w.WriteByte('"')
+		html.RenderAttributes(w, n, html.LinkAttributeFilter)
+		_ = w.WriteByte('>')
+	} else {
+		_, _ = w.WriteString(`">`)
+	}
+	_, _ = w.Write(util.EscapeHTML(label))
+	_, _ = w.WriteString(`</a>`)
+	return ast.WalkContinue, nil
+}
+
 func (r *hookedRenderer) renderDefaultHeading(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
 	n := node.(*ast.Heading)
 	if entering {