gotosocial/vendor/github.com/yuin/goldmark/extension/footnote.go

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package extension
import (
"bytes"
"fmt"
"strconv"
"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"
)
var footnoteListKey = parser.NewContextKey()
var footnoteLinkListKey = 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
}
fnlink := ast.NewFootnoteLink(index)
var fnlist []*ast.FootnoteLink
if tmp := pc.Get(footnoteLinkListKey); tmp != nil {
fnlist = tmp.([]*ast.FootnoteLink)
} else {
fnlist = []*ast.FootnoteLink{}
pc.Set(footnoteLinkListKey, fnlist)
}
pc.Set(footnoteLinkListKey, append(fnlist, fnlink))
if line[0] == '!' {
parent.AppendChild(parent, gast.NewTextSegment(text.NewSegment(segment.Start, segment.Start+1)))
}
return fnlink
}
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
var fnlist []*ast.FootnoteLink
if tmp := pc.Get(footnoteListKey); tmp != nil {
list = tmp.(*ast.FootnoteList)
}
if tmp := pc.Get(footnoteLinkListKey); tmp != nil {
fnlist = tmp.([]*ast.FootnoteLink)
}
pc.Set(footnoteListKey, nil)
pc.Set(footnoteLinkListKey, nil)
if list == nil {
return
}
counter := map[int]int{}
if fnlist != nil {
for _, fnlink := range fnlist {
if fnlink.Index >= 0 {
counter[fnlink.Index]++
}
}
refCounter := map[int]int{}
for _, fnlink := range fnlist {
fnlink.RefCount = counter[fnlink.Index]
if _, ok := refCounter[fnlink.Index]; !ok {
refCounter[fnlink.Index] = 0
}
fnlink.RefIndex = refCounter[fnlink.Index]
refCounter[fnlink.Index]++
}
}
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
}
fn := footnote.(*ast.Footnote)
index := fn.Index
if index < 0 {
list.RemoveChild(list, footnote)
} else {
refCount := counter[index]
backLink := ast.NewFootnoteBacklink(index)
backLink.RefCount = refCount
backLink.RefIndex = 0
container.AppendChild(container, backLink)
if refCount > 1 {
for i := 1; i < refCount; i++ {
backLink := ast.NewFootnoteBacklink(index)
backLink.RefCount = refCount
backLink.RefIndex = i
container.AppendChild(container, backLink)
}
}
}
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)
}
// FootnoteConfig holds configuration values for the footnote extension.
//
// Link* and Backlink* configurations have some variables:
// Occurrances of “^^” in the string will be replaced by the
// corresponding footnote number in the HTML output.
// Occurrances of “%%” will be replaced by a number for the
// reference (footnotes can have multiple references).
type FootnoteConfig struct {
html.Config
// IDPrefix is a prefix for the id attributes generated by footnotes.
IDPrefix []byte
// IDPrefix is a function that determines the id attribute for given Node.
IDPrefixFunction func(gast.Node) []byte
// LinkTitle is an optional title attribute for footnote links.
LinkTitle []byte
// BacklinkTitle is an optional title attribute for footnote backlinks.
BacklinkTitle []byte
// LinkClass is a class for footnote links.
LinkClass []byte
// BacklinkClass is a class for footnote backlinks.
BacklinkClass []byte
// BacklinkHTML is an HTML content for footnote backlinks.
BacklinkHTML []byte
}
// FootnoteOption interface is a functional option interface for the extension.
type FootnoteOption interface {
renderer.Option
// SetFootnoteOption sets given option to the extension.
SetFootnoteOption(*FootnoteConfig)
}
// NewFootnoteConfig returns a new Config with defaults.
func NewFootnoteConfig() FootnoteConfig {
return FootnoteConfig{
Config: html.NewConfig(),
LinkTitle: []byte(""),
BacklinkTitle: []byte(""),
LinkClass: []byte("footnote-ref"),
BacklinkClass: []byte("footnote-backref"),
BacklinkHTML: []byte("&#x21a9;&#xfe0e;"),
}
}
// SetOption implements renderer.SetOptioner.
func (c *FootnoteConfig) SetOption(name renderer.OptionName, value interface{}) {
switch name {
case optFootnoteIDPrefixFunction:
c.IDPrefixFunction = value.(func(gast.Node) []byte)
case optFootnoteIDPrefix:
c.IDPrefix = value.([]byte)
case optFootnoteLinkTitle:
c.LinkTitle = value.([]byte)
case optFootnoteBacklinkTitle:
c.BacklinkTitle = value.([]byte)
case optFootnoteLinkClass:
c.LinkClass = value.([]byte)
case optFootnoteBacklinkClass:
c.BacklinkClass = value.([]byte)
case optFootnoteBacklinkHTML:
c.BacklinkHTML = value.([]byte)
default:
c.Config.SetOption(name, value)
}
}
type withFootnoteHTMLOptions struct {
value []html.Option
}
func (o *withFootnoteHTMLOptions) SetConfig(c *renderer.Config) {
if o.value != nil {
for _, v := range o.value {
v.(renderer.Option).SetConfig(c)
}
}
}
func (o *withFootnoteHTMLOptions) SetFootnoteOption(c *FootnoteConfig) {
if o.value != nil {
for _, v := range o.value {
v.SetHTMLOption(&c.Config)
}
}
}
// WithFootnoteHTMLOptions is functional option that wraps goldmark HTMLRenderer options.
func WithFootnoteHTMLOptions(opts ...html.Option) FootnoteOption {
return &withFootnoteHTMLOptions{opts}
}
const optFootnoteIDPrefix renderer.OptionName = "FootnoteIDPrefix"
type withFootnoteIDPrefix struct {
value []byte
}
func (o *withFootnoteIDPrefix) SetConfig(c *renderer.Config) {
c.Options[optFootnoteIDPrefix] = o.value
}
func (o *withFootnoteIDPrefix) SetFootnoteOption(c *FootnoteConfig) {
c.IDPrefix = o.value
}
// WithFootnoteIDPrefix is a functional option that is a prefix for the id attributes generated by footnotes.
func WithFootnoteIDPrefix(a []byte) FootnoteOption {
return &withFootnoteIDPrefix{a}
}
const optFootnoteIDPrefixFunction renderer.OptionName = "FootnoteIDPrefixFunction"
type withFootnoteIDPrefixFunction struct {
value func(gast.Node) []byte
}
func (o *withFootnoteIDPrefixFunction) SetConfig(c *renderer.Config) {
c.Options[optFootnoteIDPrefixFunction] = o.value
}
func (o *withFootnoteIDPrefixFunction) SetFootnoteOption(c *FootnoteConfig) {
c.IDPrefixFunction = o.value
}
// WithFootnoteIDPrefixFunction is a functional option that is a prefix for the id attributes generated by footnotes.
func WithFootnoteIDPrefixFunction(a func(gast.Node) []byte) FootnoteOption {
return &withFootnoteIDPrefixFunction{a}
}
const optFootnoteLinkTitle renderer.OptionName = "FootnoteLinkTitle"
type withFootnoteLinkTitle struct {
value []byte
}
func (o *withFootnoteLinkTitle) SetConfig(c *renderer.Config) {
c.Options[optFootnoteLinkTitle] = o.value
}
func (o *withFootnoteLinkTitle) SetFootnoteOption(c *FootnoteConfig) {
c.LinkTitle = o.value
}
// WithFootnoteLinkTitle is a functional option that is an optional title attribute for footnote links.
func WithFootnoteLinkTitle(a []byte) FootnoteOption {
return &withFootnoteLinkTitle{a}
}
const optFootnoteBacklinkTitle renderer.OptionName = "FootnoteBacklinkTitle"
type withFootnoteBacklinkTitle struct {
value []byte
}
func (o *withFootnoteBacklinkTitle) SetConfig(c *renderer.Config) {
c.Options[optFootnoteBacklinkTitle] = o.value
}
func (o *withFootnoteBacklinkTitle) SetFootnoteOption(c *FootnoteConfig) {
c.BacklinkTitle = o.value
}
// WithFootnoteBacklinkTitle is a functional option that is an optional title attribute for footnote backlinks.
func WithFootnoteBacklinkTitle(a []byte) FootnoteOption {
return &withFootnoteBacklinkTitle{a}
}
const optFootnoteLinkClass renderer.OptionName = "FootnoteLinkClass"
type withFootnoteLinkClass struct {
value []byte
}
func (o *withFootnoteLinkClass) SetConfig(c *renderer.Config) {
c.Options[optFootnoteLinkClass] = o.value
}
func (o *withFootnoteLinkClass) SetFootnoteOption(c *FootnoteConfig) {
c.LinkClass = o.value
}
// WithFootnoteLinkClass is a functional option that is a class for footnote links.
func WithFootnoteLinkClass(a []byte) FootnoteOption {
return &withFootnoteLinkClass{a}
}
const optFootnoteBacklinkClass renderer.OptionName = "FootnoteBacklinkClass"
type withFootnoteBacklinkClass struct {
value []byte
}
func (o *withFootnoteBacklinkClass) SetConfig(c *renderer.Config) {
c.Options[optFootnoteBacklinkClass] = o.value
}
func (o *withFootnoteBacklinkClass) SetFootnoteOption(c *FootnoteConfig) {
c.BacklinkClass = o.value
}
// WithFootnoteBacklinkClass is a functional option that is a class for footnote backlinks.
func WithFootnoteBacklinkClass(a []byte) FootnoteOption {
return &withFootnoteBacklinkClass{a}
}
const optFootnoteBacklinkHTML renderer.OptionName = "FootnoteBacklinkHTML"
type withFootnoteBacklinkHTML struct {
value []byte
}
func (o *withFootnoteBacklinkHTML) SetConfig(c *renderer.Config) {
c.Options[optFootnoteBacklinkHTML] = o.value
}
func (o *withFootnoteBacklinkHTML) SetFootnoteOption(c *FootnoteConfig) {
c.BacklinkHTML = o.value
}
// WithFootnoteBacklinkHTML is an HTML content for footnote backlinks.
func WithFootnoteBacklinkHTML(a []byte) FootnoteOption {
return &withFootnoteBacklinkHTML{a}
}
// FootnoteHTMLRenderer is a renderer.NodeRenderer implementation that
// renders FootnoteLink nodes.
type FootnoteHTMLRenderer struct {
FootnoteConfig
}
// NewFootnoteHTMLRenderer returns a new FootnoteHTMLRenderer.
func NewFootnoteHTMLRenderer(opts ...FootnoteOption) renderer.NodeRenderer {
r := &FootnoteHTMLRenderer{
FootnoteConfig: NewFootnoteConfig(),
}
for _, opt := range opts {
opt.SetFootnoteOption(&r.FootnoteConfig)
}
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="`)
_, _ = w.Write(r.idPrefix(node))
_, _ = w.WriteString(`fnref`)
if n.RefIndex > 0 {
_, _ = w.WriteString(fmt.Sprintf("%v", n.RefIndex))
}
_ = w.WriteByte(':')
_, _ = w.WriteString(is)
_, _ = w.WriteString(`"><a href="#`)
_, _ = w.Write(r.idPrefix(node))
_, _ = w.WriteString(`fn:`)
_, _ = w.WriteString(is)
_, _ = w.WriteString(`" class="`)
_, _ = w.Write(applyFootnoteTemplate(r.FootnoteConfig.LinkClass,
n.Index, n.RefCount))
if len(r.FootnoteConfig.LinkTitle) > 0 {
_, _ = w.WriteString(`" title="`)
_, _ = w.Write(util.EscapeHTML(applyFootnoteTemplate(r.FootnoteConfig.LinkTitle, n.Index, n.RefCount)))
}
_, _ = w.WriteString(`" 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(`&#160;<a href="#`)
_, _ = w.Write(r.idPrefix(node))
_, _ = w.WriteString(`fnref`)
if n.RefIndex > 0 {
_, _ = w.WriteString(fmt.Sprintf("%v", n.RefIndex))
}
_ = w.WriteByte(':')
_, _ = w.WriteString(is)
_, _ = w.WriteString(`" class="`)
_, _ = w.Write(applyFootnoteTemplate(r.FootnoteConfig.BacklinkClass, n.Index, n.RefCount))
if len(r.FootnoteConfig.BacklinkTitle) > 0 {
_, _ = w.WriteString(`" title="`)
_, _ = w.Write(util.EscapeHTML(applyFootnoteTemplate(r.FootnoteConfig.BacklinkTitle, n.Index, n.RefCount)))
}
_, _ = w.WriteString(`" role="doc-backlink">`)
_, _ = w.Write(applyFootnoteTemplate(r.FootnoteConfig.BacklinkHTML, n.Index, n.RefCount))
_, _ = 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="`)
_, _ = w.Write(r.idPrefix(node))
_, _ = w.WriteString(`fn:`)
_, _ = w.WriteString(is)
_, _ = w.WriteString(`"`)
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) {
if entering {
_, _ = w.WriteString(`<div 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("</div>\n")
}
return gast.WalkContinue, nil
}
func (r *FootnoteHTMLRenderer) idPrefix(node gast.Node) []byte {
if r.FootnoteConfig.IDPrefix != nil {
return r.FootnoteConfig.IDPrefix
}
if r.FootnoteConfig.IDPrefixFunction != nil {
return r.FootnoteConfig.IDPrefixFunction(node)
}
return []byte("")
}
func applyFootnoteTemplate(b []byte, index, refCount int) []byte {
fast := true
for i, c := range b {
if i != 0 {
if b[i-1] == '^' && c == '^' {
fast = false
break
}
if b[i-1] == '%' && c == '%' {
fast = false
break
}
}
}
if fast {
return b
}
is := []byte(strconv.Itoa(index))
rs := []byte(strconv.Itoa(refCount))
ret := bytes.Replace(b, []byte("^^"), is, -1)
return bytes.Replace(ret, []byte("%%"), rs, -1)
}
type footnote struct {
options []FootnoteOption
}
// Footnote is an extension that allow you to use PHP Markdown Extra Footnotes.
var Footnote = &footnote{
options: []FootnoteOption{},
}
// NewFootnote returns a new extension with given options.
func NewFootnote(opts ...FootnoteOption) goldmark.Extender {
return &footnote{
options: opts,
}
}
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(e.options...), 500),
))
}