forgejo/vendor/github.com/yuin/goldmark/extension/footnote.go
zeripath 27757714d0 Change markdown rendering from blackfriday to goldmark (#9533)
* Move to goldmark

Markdown rendering moved from blackfriday to the goldmark.

Multiple subtle changes required to the goldmark extensions to keep
current rendering and defaults.

Can go further with goldmark linkify and have this work within markdown
rendering making the link processor unnecessary.

Need to think about how to go about allowing extensions - at present it
seems that these would be hard to do without recompilation.

* linter fixes

Co-authored-by: Lauris BH <lauris@nix.lv>
2019-12-31 03:53:28 +02:00

337 lines
9 KiB
Go

package extension
import (
"bytes"
"github.com/yuin/goldmark"
gast "github.com/yuin/goldmark/ast"
"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"
"strconv"
)
var footnoteListKey = parser.NewContextKey()
type footnoteBlockParser struct {
}
var defaultFootnoteBlockParser = &footnoteBlockParser{}
// NewFootnoteBlockParser returns a new parser.BlockParser that can parse
// footnotes of the Markdown(PHP Markdown Extra) text.
func NewFootnoteBlockParser() parser.BlockParser {
return defaultFootnoteBlockParser
}
func (b *footnoteBlockParser) Trigger() []byte {
return []byte{'['}
}
func (b *footnoteBlockParser) Open(parent gast.Node, reader text.Reader, pc parser.Context) (gast.Node, parser.State) {
line, segment := reader.PeekLine()
pos := pc.BlockOffset()
if pos < 0 || line[pos] != '[' {
return nil, parser.NoChildren
}
pos++
if pos > len(line)-1 || line[pos] != '^' {
return nil, parser.NoChildren
}
open := pos + 1
closes := 0
closure := util.FindClosure(line[pos+1:], '[', ']', false, false)
closes = pos + 1 + closure
next := closes + 1
if closure > -1 {
if next >= len(line) || line[next] != ':' {
return nil, parser.NoChildren
}
} else {
return nil, parser.NoChildren
}
padding := segment.Padding
label := reader.Value(text.NewSegment(segment.Start+open-padding, segment.Start+closes-padding))
if util.IsBlank(label) {
return nil, parser.NoChildren
}
item := ast.NewFootnote(label)
pos = next + 1 - padding
if pos >= len(line) {
reader.Advance(pos)
return item, parser.NoChildren
}
reader.AdvanceAndSetPadding(pos, padding)
return item, parser.HasChildren
}
func (b *footnoteBlockParser) Continue(node gast.Node, reader text.Reader, pc parser.Context) parser.State {
line, _ := reader.PeekLine()
if util.IsBlank(line) {
return parser.Continue | parser.HasChildren
}
childpos, padding := util.IndentPosition(line, reader.LineOffset(), 4)
if childpos < 0 {
return parser.Close
}
reader.AdvanceAndSetPadding(childpos, padding)
return parser.Continue | parser.HasChildren
}
func (b *footnoteBlockParser) Close(node gast.Node, reader text.Reader, pc parser.Context) {
var list *ast.FootnoteList
if tlist := pc.Get(footnoteListKey); tlist != nil {
list = tlist.(*ast.FootnoteList)
} else {
list = ast.NewFootnoteList()
pc.Set(footnoteListKey, list)
node.Parent().InsertBefore(node.Parent(), node, list)
}
node.Parent().RemoveChild(node.Parent(), node)
list.AppendChild(list, node)
}
func (b *footnoteBlockParser) CanInterruptParagraph() bool {
return true
}
func (b *footnoteBlockParser) CanAcceptIndentedLine() bool {
return false
}
type footnoteParser struct {
}
var defaultFootnoteParser = &footnoteParser{}
// NewFootnoteParser returns a new parser.InlineParser that can parse
// footnote links of the Markdown(PHP Markdown Extra) text.
func NewFootnoteParser() parser.InlineParser {
return defaultFootnoteParser
}
func (s *footnoteParser) Trigger() []byte {
// footnote syntax probably conflict with the image syntax.
// So we need trigger this parser with '!'.
return []byte{'!', '['}
}
func (s *footnoteParser) Parse(parent gast.Node, block text.Reader, pc parser.Context) gast.Node {
line, segment := block.PeekLine()
pos := 1
if len(line) > 0 && line[0] == '!' {
pos++
}
if pos >= len(line) || line[pos] != '^' {
return nil
}
pos++
if pos >= len(line) {
return nil
}
open := pos
closure := util.FindClosure(line[pos:], '[', ']', false, false)
if closure < 0 {
return nil
}
closes := pos + closure
value := block.Value(text.NewSegment(segment.Start+open, segment.Start+closes))
block.Advance(closes + 1)
var list *ast.FootnoteList
if tlist := pc.Get(footnoteListKey); tlist != nil {
list = tlist.(*ast.FootnoteList)
}
if list == nil {
return nil
}
index := 0
for def := list.FirstChild(); def != nil; def = def.NextSibling() {
d := def.(*ast.Footnote)
if bytes.Equal(d.Ref, value) {
if d.Index < 0 {
list.Count += 1
d.Index = list.Count
}
index = d.Index
break
}
}
if index == 0 {
return nil
}
return ast.NewFootnoteLink(index)
}
type footnoteASTTransformer struct {
}
var defaultFootnoteASTTransformer = &footnoteASTTransformer{}
// NewFootnoteASTTransformer returns a new parser.ASTTransformer that
// insert a footnote list to the last of the document.
func NewFootnoteASTTransformer() parser.ASTTransformer {
return defaultFootnoteASTTransformer
}
func (a *footnoteASTTransformer) Transform(node *gast.Document, reader text.Reader, pc parser.Context) {
var list *ast.FootnoteList
if tlist := pc.Get(footnoteListKey); tlist != nil {
list = tlist.(*ast.FootnoteList)
} else {
return
}
pc.Set(footnoteListKey, nil)
for footnote := list.FirstChild(); footnote != nil; {
var container gast.Node = footnote
next := footnote.NextSibling()
if fc := container.LastChild(); fc != nil && gast.IsParagraph(fc) {
container = fc
}
index := footnote.(*ast.Footnote).Index
if index < 0 {
list.RemoveChild(list, footnote)
} else {
container.AppendChild(container, ast.NewFootnoteBackLink(index))
}
footnote = next
}
list.SortChildren(func(n1, n2 gast.Node) int {
if n1.(*ast.Footnote).Index < n2.(*ast.Footnote).Index {
return -1
}
return 1
})
if list.Count <= 0 {
list.Parent().RemoveChild(list.Parent(), list)
return
}
node.AppendChild(node, list)
}
// FootnoteHTMLRenderer is a renderer.NodeRenderer implementation that
// renders FootnoteLink nodes.
type FootnoteHTMLRenderer struct {
html.Config
}
// NewFootnoteHTMLRenderer returns a new FootnoteHTMLRenderer.
func NewFootnoteHTMLRenderer(opts ...html.Option) renderer.NodeRenderer {
r := &FootnoteHTMLRenderer{
Config: html.NewConfig(),
}
for _, opt := range opts {
opt.SetHTMLOption(&r.Config)
}
return r
}
// RegisterFuncs implements renderer.NodeRenderer.RegisterFuncs.
func (r *FootnoteHTMLRenderer) RegisterFuncs(reg renderer.NodeRendererFuncRegisterer) {
reg.Register(ast.KindFootnoteLink, r.renderFootnoteLink)
reg.Register(ast.KindFootnoteBackLink, r.renderFootnoteBackLink)
reg.Register(ast.KindFootnote, r.renderFootnote)
reg.Register(ast.KindFootnoteList, r.renderFootnoteList)
}
func (r *FootnoteHTMLRenderer) renderFootnoteLink(w util.BufWriter, source []byte, node gast.Node, entering bool) (gast.WalkStatus, error) {
if entering {
n := node.(*ast.FootnoteLink)
is := strconv.Itoa(n.Index)
_, _ = w.WriteString(`<sup id="fnref:`)
_, _ = w.WriteString(is)
_, _ = w.WriteString(`"><a href="#fn:`)
_, _ = w.WriteString(is)
_, _ = w.WriteString(`" class="footnote-ref" role="doc-noteref">`)
_, _ = w.WriteString(is)
_, _ = w.WriteString(`</a></sup>`)
}
return gast.WalkContinue, nil
}
func (r *FootnoteHTMLRenderer) renderFootnoteBackLink(w util.BufWriter, source []byte, node gast.Node, entering bool) (gast.WalkStatus, error) {
if entering {
n := node.(*ast.FootnoteBackLink)
is := strconv.Itoa(n.Index)
_, _ = w.WriteString(` <a href="#fnref:`)
_, _ = w.WriteString(is)
_, _ = w.WriteString(`" class="footnote-backref" role="doc-backlink">`)
_, _ = w.WriteString("&#x21a9;&#xfe0e;")
_, _ = w.WriteString(`</a>`)
}
return gast.WalkContinue, nil
}
func (r *FootnoteHTMLRenderer) renderFootnote(w util.BufWriter, source []byte, node gast.Node, entering bool) (gast.WalkStatus, error) {
n := node.(*ast.Footnote)
is := strconv.Itoa(n.Index)
if entering {
_, _ = w.WriteString(`<li id="fn:`)
_, _ = w.WriteString(is)
_, _ = w.WriteString(`" role="doc-endnote"`)
if node.Attributes() != nil {
html.RenderAttributes(w, node, html.ListItemAttributeFilter)
}
_, _ = w.WriteString(">\n")
} else {
_, _ = w.WriteString("</li>\n")
}
return gast.WalkContinue, nil
}
func (r *FootnoteHTMLRenderer) renderFootnoteList(w util.BufWriter, source []byte, node gast.Node, entering bool) (gast.WalkStatus, error) {
tag := "section"
if r.Config.XHTML {
tag = "div"
}
if entering {
_, _ = w.WriteString("<")
_, _ = w.WriteString(tag)
_, _ = w.WriteString(` class="footnotes" role="doc-endnotes"`)
if node.Attributes() != nil {
html.RenderAttributes(w, node, html.GlobalAttributeFilter)
}
_ = w.WriteByte('>')
if r.Config.XHTML {
_, _ = w.WriteString("\n<hr />\n")
} else {
_, _ = w.WriteString("\n<hr>\n")
}
_, _ = w.WriteString("<ol>\n")
} else {
_, _ = w.WriteString("</ol>\n")
_, _ = w.WriteString("</")
_, _ = w.WriteString(tag)
_, _ = w.WriteString(">\n")
}
return gast.WalkContinue, nil
}
type footnote struct {
}
// Footnote is an extension that allow you to use PHP Markdown Extra Footnotes.
var Footnote = &footnote{}
func (e *footnote) Extend(m goldmark.Markdown) {
m.Parser().AddOptions(
parser.WithBlockParsers(
util.Prioritized(NewFootnoteBlockParser(), 999),
),
parser.WithInlineParsers(
util.Prioritized(NewFootnoteParser(), 101),
),
parser.WithASTTransformers(
util.Prioritized(NewFootnoteASTTransformer(), 999),
),
)
m.Renderer().AddOptions(renderer.WithNodeRenderers(
util.Prioritized(NewFootnoteHTMLRenderer(), 500),
))
}