Use markdown frontmatter to provide Table of contents, language and f…

…rontmatter rendering (go-gitea#11047)

* Add control for the rendering of the frontmatter
* Add control to include a TOC
* Add control to set language - allows control of ToC header and CJK glyph choice.

Signed-off-by: Andrew Thornton [email protected]

go.mod

@@ -124,6 +124,7 @@ require (
  gopkg.in/ini.v1 v1.52.0
  gopkg.in/ldap.v3 v3.0.2
  gopkg.in/testfixtures.v2 v2.5.0
+ gopkg.in/yaml.v2 v2.2.8
  mvdan.cc/xurls/v2 v2.1.0
  strk.kbt.io/projects/go/libravatar v0.0.0-20191008002943-06d1c002b251
  xorm.io/builder v0.3.7

modules/markup/html.go

@@ -351,6 +351,27 @@ func (ctx *postProcessCtx) visitNode(node *html.Node, visitText bool) {
  visitText = false
  } else if node.Data == "code" || node.Data == "pre" {
  return
+ } else if node.Data == "i" {
+ for _, attr := range node.Attr {
+ if attr.Key != "class" {
+ continue
+ }
+ classes := strings.Split(attr.Val, " ")
+ for i, class := range classes {
+ if class == "icon" {
+ classes[0], classes[i] = classes[i], classes[0]
+ attr.Val = strings.Join(classes, " ")
+
+ // Remove all children of icons
+ child := node.FirstChild
+ for child != nil {
+ node.RemoveChild(child)
+ child = node.FirstChild
+ }
+ break
+ }
+ }
+ }
  }
  for n := node.FirstChild; n != nil; n = n.NextSibling {
  ctx.visitNode(n, visitText)

modules/markup/markdown/ast.go

@@ -0,0 +1,107 @@
+// Copyright 2020 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package markdown
+
+import "github.com/yuin/goldmark/ast"
+
+// Details is a block that contains Summary and details
+type Details struct {
+ ast.BaseBlock
+}
+
+// Dump implements Node.Dump .
+func (n *Details) Dump(source []byte, level int) {
+ ast.DumpHelper(n, source, level, nil, nil)
+}
+
+// KindDetails is the NodeKind for Details
+var KindDetails = ast.NewNodeKind("Details")
+
+// Kind implements Node.Kind.
+func (n *Details) Kind() ast.NodeKind {
+ return KindDetails
+}
+
+// NewDetails returns a new Paragraph node.
+func NewDetails() *Details {
+ return &Details{
+ BaseBlock: ast.BaseBlock{},
+ }
+}
+
+// IsDetails returns true if the given node implements the Details interface,
+// otherwise false.
+func IsDetails(node ast.Node) bool {
+ _, ok := node.(*Details)
+ return ok
+}
+
+// Summary is a block that contains the summary of details block
+type Summary struct {
+ ast.BaseBlock
+}
+
+// Dump implements Node.Dump .
+func (n *Summary) Dump(source []byte, level int) {
+ ast.DumpHelper(n, source, level, nil, nil)
+}
+
+// KindSummary is the NodeKind for Summary
+var KindSummary = ast.NewNodeKind("Summary")
+
+// Kind implements Node.Kind.
+func (n *Summary) Kind() ast.NodeKind {
+ return KindSummary
+}
+
+// NewSummary returns a new Summary node.
+func NewSummary() *Summary {
+ return &Summary{
+ BaseBlock: ast.BaseBlock{},
+ }
+}
+
+// IsSummary returns true if the given node implements the Summary interface,
+// otherwise false.
+func IsSummary(node ast.Node) bool {
+ _, ok := node.(*Summary)
+ return ok
+}
+
+// Icon is an inline for a fomantic icon
+type Icon struct {
+ ast.BaseInline
+ Name []byte
+}
+
+// Dump implements Node.Dump .
+func (n *Icon) Dump(source []byte, level int) {
+ m := map[string]string{}
+ m["Name"] = string(n.Name)
+ ast.DumpHelper(n, source, level, m, nil)
+}
+
+// KindIcon is the NodeKind for Icon
+var KindIcon = ast.NewNodeKind("Icon")
+
+// Kind implements Node.Kind.
+func (n *Icon) Kind() ast.NodeKind {
+ return KindIcon
+}
+
+// NewIcon returns a new Paragraph node.
+func NewIcon(name string) *Icon {
+ return &Icon{
+ BaseInline: ast.BaseInline{},
+ Name: []byte(name),
+ }
+}
+
+// IsIcon returns true if the given node implements the Icon interface,
+// otherwise false.
+func IsIcon(node ast.Node) bool {
+ _, ok := node.(*Icon)
+ return ok
+}

modules/markup/markdown/goldmark.go

@@ -7,12 +7,16 @@ package markdown
 import (
  "bytes"
  "fmt"
+ "regexp"
  "strings"
 
+ "code.gitea.io/gitea/modules/log"
  "code.gitea.io/gitea/modules/markup"
  "code.gitea.io/gitea/modules/markup/common"
+ "code.gitea.io/gitea/modules/setting"
  giteautil "code.gitea.io/gitea/modules/util"
 
+ meta "github.com/yuin/goldmark-meta"
  "github.com/yuin/goldmark/ast"
  east "github.com/yuin/goldmark/extension/ast"
  "github.com/yuin/goldmark/parser"
@@ -24,17 +28,56 @@ import (
 
 var byteMailto = []byte("mailto:")
 
-// GiteaASTTransformer is a default transformer of the goldmark tree.
-type GiteaASTTransformer struct{}
+// Header holds the data about a header.
+type Header struct {
+ Level int
+ Text string
+ ID string
+}
+
+// ASTTransformer is a default transformer of the goldmark tree.
+type ASTTransformer struct{}
 
 // Transform transforms the given AST tree.
-func (g *GiteaASTTransformer) Transform(node *ast.Document, reader text.Reader, pc parser.Context) {
+func (g *ASTTransformer) Transform(node *ast.Document, reader text.Reader, pc parser.Context) {
+ metaData := meta.GetItems(pc)
+ firstChild := node.FirstChild()
+ createTOC := false
+ var toc = []Header{}
+ rc := &RenderConfig{
+ Meta: "table",
+ Icon: "table",
+ Lang: "",
+ }
+ if metaData != nil {
+ rc.ToRenderConfig(metaData)
+
+ metaNode := rc.toMetaNode(metaData)
+ if metaNode != nil {
+ node.InsertBefore(node, firstChild, metaNode)
+ }
+ createTOC = rc.TOC
+ toc = make([]Header, 0, 100)
+ }
+
  _ = ast.Walk(node, func(n ast.Node, entering bool) (ast.WalkStatus, error) {
  if !entering {
  return ast.WalkContinue, nil
  }
 
  switch v := n.(type) {
+ case *ast.Heading:
+ if createTOC {
+ text := n.Text(reader.Source())
+ header := Header{
+ Text: util.BytesToReadOnlyString(text),
+ Level: v.Level,
+ }
+ if id, found := v.AttributeString("id"); found {
+ header.ID = util.BytesToReadOnlyString(id.([]byte))
+ }
+ toc = append(toc, header)
+ }
  case *ast.Image:
  // Images need two things:
  //
@@ -91,6 +134,21 @@ func (g *GiteaASTTransformer) Transform(node *ast.Document, reader text.Reader,
  }
  return ast.WalkContinue, nil
  })
+
+ if createTOC && len(toc) > 0 {
+ lang := rc.Lang
+ if len(lang) == 0 {
+ lang = setting.Langs[0]
+ }
+ tocNode := createTOCNode(toc, lang)
+ if tocNode != nil {
+ node.InsertBefore(node, firstChild, tocNode)
+ }
+ }
+
+ if len(rc.Lang) > 0 {
+ node.SetAttributeString("lang", []byte(rc.Lang))
+ }
 }
 
 type prefixedIDs struct {
@@ -139,10 +197,10 @@ func newPrefixedIDs() *prefixedIDs {
  }
 }
 
-// NewTaskCheckBoxHTMLRenderer creates a TaskCheckBoxHTMLRenderer to render tasklists
+// NewHTMLRenderer creates a HTMLRenderer to render
 // in the gitea form.
-func NewTaskCheckBoxHTMLRenderer(opts ...html.Option) renderer.NodeRenderer {
- r := &TaskCheckBoxHTMLRenderer{
+func NewHTMLRenderer(opts ...html.Option) renderer.NodeRenderer {
+ r := &HTMLRenderer{
  Config: html.NewConfig(),
  }
  for _, opt := range opts {
@@ -151,19 +209,109 @@ func NewTaskCheckBoxHTMLRenderer(opts ...html.Option) renderer.NodeRenderer {
  return r
 }
 
-// TaskCheckBoxHTMLRenderer is a renderer.NodeRenderer implementation that
-// renders checkboxes in list items.
-// Overrides the default goldmark one to present the gitea format
-type TaskCheckBoxHTMLRenderer struct {
+// HTMLRenderer is a renderer.NodeRenderer implementation that
+// renders gitea specific features.
+type HTMLRenderer struct {
  html.Config
 }
 
 // RegisterFuncs implements renderer.NodeRenderer.RegisterFuncs.
-func (r *TaskCheckBoxHTMLRenderer) RegisterFuncs(reg renderer.NodeRendererFuncRegisterer) {
+func (r *HTMLRenderer) RegisterFuncs(reg renderer.NodeRendererFuncRegisterer) {
+ reg.Register(ast.KindDocument, r.renderDocument)
+ reg.Register(KindDetails, r.renderDetails)
+ reg.Register(KindSummary, r.renderSummary)
+ reg.Register(KindIcon, r.renderIcon)
  reg.Register(east.KindTaskCheckBox, r.renderTaskCheckBox)
 }
 
-func (r *TaskCheckBoxHTMLRenderer) renderTaskCheckBox(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+func (r *HTMLRenderer) renderDocument(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+ log.Info("renderDocument %v", node)
+ n := node.(*ast.Document)
+
+ if val, has := n.AttributeString("lang"); has {
+ var err error
+ if entering {
+ _, err = w.WriteString("<div")
+ if err == nil {
+ _, err = w.WriteString(fmt.Sprintf(` lang=%q`, val))
+ }
+ if err == nil {
+ _, err = w.WriteRune('>')
+ }
+ } else {
+ _, err = w.WriteString("</div>")
+ }
+
+ if err != nil {
+ return ast.WalkStop, err
+ }
+ }
+
+ return ast.WalkContinue, nil
+}
+
+func (r *HTMLRenderer) renderDetails(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+ var err error
+ if entering {
+ _, err = w.WriteString("<details>")
+ } else {
+ _, err = w.WriteString("</details>")
+ }
+
+ if err != nil {
+ return ast.WalkStop, err
+ }
+
+ return ast.WalkContinue, nil
+}
+
+func (r *HTMLRenderer) renderSummary(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+ var err error
+ if entering {
+ _, err = w.WriteString("<summary>")
+ } else {
+ _, err = w.WriteString("</summary>")
+ }
+
+ if err != nil {
+ return ast.WalkStop, err
+ }
+
+ return ast.WalkContinue, nil
+}
+
+var validNameRE = regexp.MustCompile("^[a-z ]+$")
+
+func (r *HTMLRenderer) renderIcon(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+ if !entering {
+ return ast.WalkContinue, nil
+ }
+
+ n := node.(*Icon)
+
+ name := strings.TrimSpace(strings.ToLower(string(n.Name)))
+
+ if len(name) == 0 {
+ // skip this
+ return ast.WalkContinue, nil
+ }
+
+ if !validNameRE.MatchString(name) {
+ // skip this
+ return ast.WalkContinue, nil
+ }
+
+ var err error
+ _, err = w.WriteString(fmt.Sprintf(`<i class="icon %s"></i>`, name))
+
+ if err != nil {
+ return ast.WalkStop, err
+ }
+
+ return ast.WalkContinue, nil
+}
+
+func (r *HTMLRenderer) renderTaskCheckBox(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
  if !entering {
  return ast.WalkContinue, nil
  }