forgejo/modules/markup/markdown/goldmark.go

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// Copyright 2019 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT
package markdown
import (
"bytes"
"fmt"
"regexp"
"strings"
"code.gitea.io/gitea/modules/container"
"code.gitea.io/gitea/modules/markup"
"code.gitea.io/gitea/modules/markup/common"
"code.gitea.io/gitea/modules/setting"
"code.gitea.io/gitea/modules/svg"
giteautil "code.gitea.io/gitea/modules/util"
"github.com/microcosm-cc/bluemonday/css"
"github.com/yuin/goldmark/ast"
east "github.com/yuin/goldmark/extension/ast"
"github.com/yuin/goldmark/parser"
"github.com/yuin/goldmark/renderer"
"github.com/yuin/goldmark/renderer/html"
"github.com/yuin/goldmark/text"
"github.com/yuin/goldmark/util"
)
var byteMailto = []byte("mailto:")
// ASTTransformer is a default transformer of the goldmark tree.
type ASTTransformer struct{}
// Transform transforms the given AST tree.
func (g *ASTTransformer) Transform(node *ast.Document, reader text.Reader, pc parser.Context) {
firstChild := node.FirstChild()
tocMode := ""
ctx := pc.Get(renderContextKey).(*markup.RenderContext)
rc := pc.Get(renderConfigKey).(*RenderConfig)
tocList := make([]markup.Header, 0, 20)
if rc.yamlNode != nil {
metaNode := rc.toMetaNode()
if metaNode != nil {
node.InsertBefore(node, firstChild, metaNode)
}
tocMode = rc.TOC
}
applyElementDir := func(n ast.Node) {
if markup.DefaultProcessorHelper.ElementDir != "" {
n.SetAttributeString("dir", []byte(markup.DefaultProcessorHelper.ElementDir))
}
}
_ = 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:
for _, attr := range v.Attributes() {
if _, ok := attr.Value.([]byte); !ok {
v.SetAttribute(attr.Name, []byte(fmt.Sprintf("%v", attr.Value)))
}
}
txt := n.Text(reader.Source())
header := markup.Header{
Text: util.BytesToReadOnlyString(txt),
Level: v.Level,
}
if id, found := v.AttributeString("id"); found {
header.ID = util.BytesToReadOnlyString(id.([]byte))
}
tocList = append(tocList, header)
applyElementDir(v)
case *ast.Paragraph:
applyElementDir(v)
case *ast.Image:
// Images need two things:
//
// 1. Their src needs to munged to be a real value
// 2. If they're not wrapped with a link they need a link wrapper
// Check if the destination is a real link
if len(v.Destination) > 0 && !markup.IsLink(v.Destination) {
v.Destination = []byte(giteautil.URLJoin(
ctx.Links.ResolveMediaLink(ctx.IsWiki),
strings.TrimLeft(string(v.Destination), "/"),
))
}
parent := n.Parent()
// Create a link around image only if parent is not already a link
if _, ok := parent.(*ast.Link); !ok && parent != nil {
next := n.NextSibling()
// Create a link wrapper
wrap := ast.NewLink()
wrap.Destination = v.Destination
wrap.Title = v.Title
wrap.SetAttributeString("target", []byte("_blank"))
// Duplicate the current image node
image := ast.NewImage(ast.NewLink())
image.Destination = v.Destination
image.Title = v.Title
for _, attr := range v.Attributes() {
image.SetAttribute(attr.Name, attr.Value)
}
for child := v.FirstChild(); child != nil; {
next := child.NextSibling()
image.AppendChild(image, child)
child = next
}
// Append our duplicate image to the wrapper link
wrap.AppendChild(wrap, image)
// Wire in the next sibling
wrap.SetNextSibling(next)
// Replace the current node with the wrapper link
parent.ReplaceChild(parent, n, wrap)
// But most importantly ensure the next sibling is still on the old image too
v.SetNextSibling(next)
}
case *ast.Link:
// Links need their href to munged to be a real value
link := v.Destination
if len(link) > 0 && !markup.IsLink(link) &&
link[0] != '#' && !bytes.HasPrefix(link, byteMailto) {
// special case: this is not a link, a hash link or a mailto:, so it's a
// relative URL
var base string
if ctx.IsWiki {
base = ctx.Links.WikiLink()
} else if ctx.Links.HasBranchInfo() {
base = ctx.Links.SrcLink()
} else {
base = ctx.Links.Base
}
link = []byte(giteautil.URLJoin(base, string(link)))
}
if len(link) > 0 && link[0] == '#' {
link = []byte("#user-content-" + string(link)[1:])
}
v.Destination = link
case *ast.List:
if v.HasChildren() {
children := make([]ast.Node, 0, v.ChildCount())
child := v.FirstChild()
for child != nil {
children = append(children, child)
child = child.NextSibling()
}
v.RemoveChildren(v)
for _, child := range children {
listItem := child.(*ast.ListItem)
if !child.HasChildren() || !child.FirstChild().HasChildren() {
v.AppendChild(v, child)
continue
}
taskCheckBox, ok := child.FirstChild().FirstChild().(*east.TaskCheckBox)
if !ok {
v.AppendChild(v, child)
continue
}
newChild := NewTaskCheckBoxListItem(listItem)
newChild.IsChecked = taskCheckBox.IsChecked
newChild.SetAttributeString("class", []byte("task-list-item"))
segments := newChild.FirstChild().Lines()
if segments.Len() > 0 {
segment := segments.At(0)
newChild.SourcePosition = rc.metaLength + segment.Start
}
v.AppendChild(v, newChild)
}
}
applyElementDir(v)
case *ast.Text:
if v.SoftLineBreak() && !v.HardLineBreak() {
if ctx.Metas["mode"] != "document" {
v.SetHardLineBreak(setting.Markdown.EnableHardLineBreakInComments)
} else {
v.SetHardLineBreak(setting.Markdown.EnableHardLineBreakInDocuments)
}
}
case *ast.CodeSpan:
colorContent := n.Text(reader.Source())
if css.ColorHandler(strings.ToLower(string(colorContent))) {
v.AppendChild(v, NewColorPreview(colorContent))
}
case *ast.Blockquote:
// We only want attention blockquotes when the AST looks like:
// Text: "["
// Text: "!TYPE"
// Text(SoftLineBreak): "]"
// grab these nodes and make sure we adhere to the attention blockquote structure
firstParagraph := v.FirstChild()
if firstParagraph.ChildCount() < 3 {
return ast.WalkContinue, nil
}
firstTextNode, ok := firstParagraph.FirstChild().(*ast.Text)
if !ok || string(firstTextNode.Segment.Value(reader.Source())) != "[" {
return ast.WalkContinue, nil
}
secondTextNode, ok := firstTextNode.NextSibling().(*ast.Text)
if !ok || !attentionTypeRE.MatchString(string(secondTextNode.Segment.Value(reader.Source()))) {
return ast.WalkContinue, nil
}
thirdTextNode, ok := secondTextNode.NextSibling().(*ast.Text)
if !ok || string(thirdTextNode.Segment.Value(reader.Source())) != "]" {
return ast.WalkContinue, nil
}
// grab attention type from markdown source
attentionType := strings.ToLower(strings.TrimPrefix(string(secondTextNode.Segment.Value(reader.Source())), "!"))
// color the blockquote
v.SetAttributeString("class", []byte("gt-py-3 attention attention-"+attentionType))
// create an emphasis to make it bold
emphasis := ast.NewEmphasis(2)
emphasis.SetAttributeString("class", []byte("attention-"+attentionType))
firstParagraph.InsertBefore(firstParagraph, firstTextNode, emphasis)
// capitalize first letter
attentionText := ast.NewString([]byte(strings.ToUpper(string(attentionType[0])) + attentionType[1:]))
// replace the ![TYPE] with icon+Type
emphasis.AppendChild(emphasis, attentionText)
for i := 0; i < 2; i++ {
lineBreak := ast.NewText()
lineBreak.SetSoftLineBreak(true)
firstParagraph.InsertAfter(firstParagraph, emphasis, lineBreak)
}
firstParagraph.InsertBefore(firstParagraph, emphasis, NewAttention(attentionType))
firstParagraph.RemoveChild(firstParagraph, firstTextNode)
firstParagraph.RemoveChild(firstParagraph, secondTextNode)
firstParagraph.RemoveChild(firstParagraph, thirdTextNode)
}
return ast.WalkContinue, nil
})
showTocInMain := tocMode == "true" /* old behavior, in main view */ || tocMode == "main"
showTocInSidebar := !showTocInMain && tocMode != "false" // not hidden, not main, then show it in sidebar
if len(tocList) > 0 && (showTocInMain || showTocInSidebar) {
if showTocInMain {
tocNode := createTOCNode(tocList, rc.Lang, nil)
node.InsertBefore(node, firstChild, tocNode)
} else {
tocNode := createTOCNode(tocList, rc.Lang, map[string]string{"open": "open"})
ctx.SidebarTocNode = tocNode
}
}
if len(rc.Lang) > 0 {
node.SetAttributeString("lang", []byte(rc.Lang))
}
}
type prefixedIDs struct {
values container.Set[string]
}
// Generate generates a new element id.
func (p *prefixedIDs) Generate(value []byte, kind ast.NodeKind) []byte {
dft := []byte("id")
if kind == ast.KindHeading {
dft = []byte("heading")
}
return p.GenerateWithDefault(value, dft)
}
// Generate generates a new element id.
func (p *prefixedIDs) GenerateWithDefault(value, dft []byte) []byte {
result := common.CleanValue(value)
if len(result) == 0 {
result = dft
}
if !bytes.HasPrefix(result, []byte("user-content-")) {
result = append([]byte("user-content-"), result...)
}
if p.values.Add(util.BytesToReadOnlyString(result)) {
return result
}
for i := 1; ; i++ {
newResult := fmt.Sprintf("%s-%d", result, i)
if p.values.Add(newResult) {
return []byte(newResult)
}
}
}
// Put puts a given element id to the used ids table.
func (p *prefixedIDs) Put(value []byte) {
p.values.Add(util.BytesToReadOnlyString(value))
}
func newPrefixedIDs() *prefixedIDs {
return &prefixedIDs{
values: make(container.Set[string]),
}
}
// NewHTMLRenderer creates a HTMLRenderer to render
// in the gitea form.
func NewHTMLRenderer(opts ...html.Option) renderer.NodeRenderer {
r := &HTMLRenderer{
Config: html.NewConfig(),
}
for _, opt := range opts {
opt.SetHTMLOption(&r.Config)
}
return r
}
// HTMLRenderer is a renderer.NodeRenderer implementation that
// renders gitea specific features.
type HTMLRenderer struct {
html.Config
}
// RegisterFuncs implements renderer.NodeRenderer.RegisterFuncs.
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(ast.KindCodeSpan, r.renderCodeSpan)
reg.Register(KindAttention, r.renderAttention)
reg.Register(KindTaskCheckBoxListItem, r.renderTaskCheckBoxListItem)
reg.Register(east.KindTaskCheckBox, r.renderTaskCheckBox)
}
// renderCodeSpan renders CodeSpan elements (like goldmark upstream does) but also renders ColorPreview elements.
// See #21474 for reference
func (r *HTMLRenderer) renderCodeSpan(w util.BufWriter, source []byte, n ast.Node, entering bool) (ast.WalkStatus, error) {
if entering {
if n.Attributes() != nil {
_, _ = w.WriteString("<code")
html.RenderAttributes(w, n, html.CodeAttributeFilter)
_ = w.WriteByte('>')
} else {
_, _ = w.WriteString("<code>")
}
for c := n.FirstChild(); c != nil; c = c.NextSibling() {
switch v := c.(type) {
case *ast.Text:
segment := v.Segment
value := segment.Value(source)
if bytes.HasSuffix(value, []byte("\n")) {
r.Writer.RawWrite(w, value[:len(value)-1])
r.Writer.RawWrite(w, []byte(" "))
} else {
r.Writer.RawWrite(w, value)
}
case *ColorPreview:
_, _ = w.WriteString(fmt.Sprintf(`<span class="color-preview" style="background-color: %v"></span>`, string(v.Color)))
}
}
return ast.WalkSkipChildren, nil
}
_, _ = w.WriteString("</code>")
return ast.WalkContinue, nil
}
// renderAttention renders a quote marked with i.e. "> **Note**" or "> **Warning**" with a corresponding svg
func (r *HTMLRenderer) renderAttention(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
if entering {
_, _ = w.WriteString(`<span class="gt-mr-2 gt-vm attention-`)
n := node.(*Attention)
_, _ = w.WriteString(strings.ToLower(n.AttentionType))
_, _ = w.WriteString(`">`)
var octiconType string
switch n.AttentionType {
case "note":
octiconType = "info"
case "tip":
octiconType = "light-bulb"
case "important":
octiconType = "report"
case "warning":
octiconType = "alert"
case "caution":
octiconType = "stop"
}
_, _ = w.WriteString(string(svg.RenderHTML("octicon-" + octiconType)))
} else {
_, _ = w.WriteString("</span>\n")
}
return ast.WalkContinue, nil
}
func (r *HTMLRenderer) renderDocument(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
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 {
if _, err = w.WriteString("<details"); err != nil {
return ast.WalkStop, err
}
html.RenderAttributes(w, node, nil)
_, err = w.WriteString(">")
} 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 ]+$")
attentionTypeRE = regexp.MustCompile("^!(NOTE|TIP|IMPORTANT|WARNING|CAUTION)$")
)
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) renderTaskCheckBoxListItem(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
n := node.(*TaskCheckBoxListItem)
if entering {
if n.Attributes() != nil {
_, _ = w.WriteString("<li")
html.RenderAttributes(w, n, html.ListItemAttributeFilter)
_ = w.WriteByte('>')
} else {
_, _ = w.WriteString("<li>")
}
fmt.Fprintf(w, `<input type="checkbox" disabled="" data-source-position="%d"`, n.SourcePosition)
if n.IsChecked {
_, _ = w.WriteString(` checked=""`)
}
if r.XHTML {
_, _ = w.WriteString(` />`)
} else {
_ = w.WriteByte('>')
}
fc := n.FirstChild()
if fc != nil {
if _, ok := fc.(*ast.TextBlock); !ok {
_ = w.WriteByte('\n')
}
}
} else {
_, _ = w.WriteString("</li>\n")
}
return ast.WalkContinue, nil
}
func (r *HTMLRenderer) renderTaskCheckBox(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
return ast.WalkContinue, nil
}