Add Markdown render hooks for tables

Fixes #9316
Fixes #12811

markup/goldmark/tables/tables.go

@@ -0,0 +1,175 @@
+// 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 tables
+
+import (
+	"github.com/gohugoio/hugo/common/herrors"
+	"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"
+	gast "github.com/yuin/goldmark/extension/ast"
+	"github.com/yuin/goldmark/renderer"
+	"github.com/yuin/goldmark/util"
+)
+
+type (
+	ext          struct{}
+	htmlRenderer struct{}
+)
+
+func New() goldmark.Extender {
+	return &ext{}
+}
+
+func (e *ext) 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(gast.KindTable, r.renderTable)
+	reg.Register(gast.KindTableHeader, r.renderHeaderOrRow)
+	reg.Register(gast.KindTableRow, r.renderHeaderOrRow)
+	reg.Register(gast.KindTableCell, r.renderCell)
+}
+
+func (r *htmlRenderer) renderTable(w util.BufWriter, source []byte, n ast.Node, entering bool) (ast.WalkStatus, error) {
+	ctx := w.(*render.Context)
+	if entering {
+		// This will be modified below.
+		table := &hooks.Table{}
+		ctx.PushValue(gast.KindTable, table)
+		return ast.WalkContinue, nil
+	}
+
+	v := ctx.PopValue(gast.KindTable)
+	if v == nil {
+		panic("table not found")
+	}
+
+	table := v.(*hooks.Table)
+
+	renderer := ctx.RenderContext().GetRenderer(hooks.TableRendererType, nil)
+	if renderer == nil {
+		panic("table hook renderer not found")
+	}
+
+	ordinal := ctx.GetAndIncrementOrdinal(gast.KindTable)
+
+	tctx := &tableContext{
+		BaseContext:      render.NewBaseContext(ctx, renderer, n, source, nil, ordinal),
+		AttributesHolder: attributes.New(n.Attributes(), attributes.AttributesOwnerGeneral),
+		tHead:            table.THead,
+		tBody:            table.TBody,
+	}
+
+	cr := renderer.(hooks.TableRenderer)
+
+	err := cr.RenderTable(
+		ctx.RenderContext().Ctx,
+		w,
+		tctx,
+	)
+	if err != nil {
+		return ast.WalkContinue, herrors.NewFileErrorFromPos(err, tctx.Position())
+	}
+
+	return ast.WalkContinue, nil
+}
+
+func (r *htmlRenderer) peekTable(ctx *render.Context) *hooks.Table {
+	v := ctx.PeekValue(gast.KindTable)
+	if v == nil {
+		panic("table not found")
+	}
+	return v.(*hooks.Table)
+}
+
+func (r *htmlRenderer) renderCell(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	ctx := w.(*render.Context)
+
+	if entering {
+		// Store the current pos so we can capture the rendered text.
+		ctx.PushPos(ctx.Buffer.Len())
+		return ast.WalkContinue, nil
+	}
+
+	n := node.(*gast.TableCell)
+
+	text := ctx.PopRenderedString()
+
+	table := r.peekTable(ctx)
+
+	var alignment string
+	switch n.Alignment {
+	case gast.AlignLeft:
+		alignment = "left"
+	case gast.AlignRight:
+		alignment = "right"
+	case gast.AlignCenter:
+		alignment = "center"
+	default:
+		alignment = "left"
+	}
+
+	cell := hooks.TableCell{Text: hstring.RenderedString(text), Alignment: alignment}
+
+	if node.Parent().Kind() == gast.KindTableHeader {
+		table.THead[len(table.THead)-1] = append(table.THead[len(table.THead)-1], cell)
+	} else {
+		table.TBody[len(table.TBody)-1] = append(table.TBody[len(table.TBody)-1], cell)
+	}
+
+	return ast.WalkContinue, nil
+}
+
+func (r *htmlRenderer) renderHeaderOrRow(w util.BufWriter, source []byte, n ast.Node, entering bool) (ast.WalkStatus, error) {
+	ctx := w.(*render.Context)
+	table := r.peekTable(ctx)
+	if entering {
+		if n.Kind() == gast.KindTableHeader {
+			table.THead = append(table.THead, hooks.TableRow{})
+		} else {
+			table.TBody = append(table.TBody, hooks.TableRow{})
+		}
+		return ast.WalkContinue, nil
+	}
+
+	return ast.WalkContinue, nil
+}
+
+type tableContext struct {
+	hooks.BaseContext
+	*attributes.AttributesHolder
+
+	tHead []hooks.TableRow
+	tBody []hooks.TableRow
+}
+
+func (c *tableContext) THead() []hooks.TableRow {
+	return c.tHead
+}
+
+func (c *tableContext) TBody() []hooks.TableRow {
+	return c.tBody
+}