blackfriday/html.go
Nathan Galt 412ca19665 Use ↩ as default params.FootnoteReturnLinkContents
This changes the default `params.FootnoteReturnLinkContents` from `<sup>[return]</sup>` to `↩\ufe0e`.

It’s very common to use `↩` in footnote links. However, some platforms like iOS and iPadOS choose to use emoji presentation for this particular character. This leads to lots of blogs, by default, looking silly on portable Apple gizmos, as described in <https://github.com/jgm/pandoc/issues/5469>. By switching to a return arrow with a disable-emojification variation selector, we get blackfriday to do the right thing by default.

Additionally, ↩ is more language-agnostic than “return” is, so blackfriday will work better out of the box for more people.
2019-06-10 16:05:36 -07:00

953 lines
24 KiB
Go

//
// Blackfriday Markdown Processor
// Available at http://github.com/russross/blackfriday
//
// Copyright © 2011 Russ Ross <russ@russross.com>.
// Distributed under the Simplified BSD License.
// See README.md for details.
//
//
//
// HTML rendering backend
//
//
package blackfriday
import (
"bytes"
"fmt"
"io"
"regexp"
"strings"
)
// HTMLFlags control optional behavior of HTML renderer.
type HTMLFlags int
// HTML renderer configuration options.
const (
HTMLFlagsNone HTMLFlags = 0
SkipHTML HTMLFlags = 1 << iota // Skip preformatted HTML blocks
SkipImages // Skip embedded images
SkipLinks // Skip all links
Safelink // Only link to trusted protocols
NofollowLinks // Only link with rel="nofollow"
NoreferrerLinks // Only link with rel="noreferrer"
NoopenerLinks // Only link with rel="noopener"
HrefTargetBlank // Add a blank target
CompletePage // Generate a complete HTML page
UseXHTML // Generate XHTML output instead of HTML
FootnoteReturnLinks // Generate a link at the end of a footnote to return to the source
Smartypants // Enable smart punctuation substitutions
SmartypantsFractions // Enable smart fractions (with Smartypants)
SmartypantsDashes // Enable smart dashes (with Smartypants)
SmartypantsLatexDashes // Enable LaTeX-style dashes (with Smartypants)
SmartypantsAngledQuotes // Enable angled double quotes (with Smartypants) for double quotes rendering
SmartypantsQuotesNBSP // Enable « French guillemets » (with Smartypants)
TOC // Generate a table of contents
)
var (
htmlTagRe = regexp.MustCompile("(?i)^" + htmlTag)
)
const (
htmlTag = "(?:" + openTag + "|" + closeTag + "|" + htmlComment + "|" +
processingInstruction + "|" + declaration + "|" + cdata + ")"
closeTag = "</" + tagName + "\\s*[>]"
openTag = "<" + tagName + attribute + "*" + "\\s*/?>"
attribute = "(?:" + "\\s+" + attributeName + attributeValueSpec + "?)"
attributeValue = "(?:" + unquotedValue + "|" + singleQuotedValue + "|" + doubleQuotedValue + ")"
attributeValueSpec = "(?:" + "\\s*=" + "\\s*" + attributeValue + ")"
attributeName = "[a-zA-Z_:][a-zA-Z0-9:._-]*"
cdata = "<!\\[CDATA\\[[\\s\\S]*?\\]\\]>"
declaration = "<![A-Z]+" + "\\s+[^>]*>"
doubleQuotedValue = "\"[^\"]*\""
htmlComment = "<!---->|<!--(?:-?[^>-])(?:-?[^-])*-->"
processingInstruction = "[<][?].*?[?][>]"
singleQuotedValue = "'[^']*'"
tagName = "[A-Za-z][A-Za-z0-9-]*"
unquotedValue = "[^\"'=<>`\\x00-\\x20]+"
)
// HTMLRendererParameters is a collection of supplementary parameters tweaking
// the behavior of various parts of HTML renderer.
type HTMLRendererParameters struct {
// Prepend this text to each relative URL.
AbsolutePrefix string
// Add this text to each footnote anchor, to ensure uniqueness.
FootnoteAnchorPrefix string
// Show this text inside the <a> tag for a footnote return link, if the
// HTML_FOOTNOTE_RETURN_LINKS flag is enabled. If blank, the string
// <sup>[return]</sup> is used.
FootnoteReturnLinkContents string
// If set, add this text to the front of each Heading ID, to ensure
// uniqueness.
HeadingIDPrefix string
// If set, add this text to the back of each Heading ID, to ensure uniqueness.
HeadingIDSuffix string
// Increase heading levels: if the offset is 1, <h1> becomes <h2> etc.
// Negative offset is also valid.
// Resulting levels are clipped between 1 and 6.
HeadingLevelOffset int
Title string // Document title (used if CompletePage is set)
CSS string // Optional CSS file URL (used if CompletePage is set)
Icon string // Optional icon file URL (used if CompletePage is set)
Flags HTMLFlags // Flags allow customizing this renderer's behavior
}
// HTMLRenderer is a type that implements the Renderer interface for HTML output.
//
// Do not create this directly, instead use the NewHTMLRenderer function.
type HTMLRenderer struct {
HTMLRendererParameters
closeTag string // how to end singleton tags: either " />" or ">"
// Track heading IDs to prevent ID collision in a single generation.
headingIDs map[string]int
lastOutputLen int
disableTags int
sr *SPRenderer
}
const (
xhtmlClose = " />"
htmlClose = ">"
)
// NewHTMLRenderer creates and configures an HTMLRenderer object, which
// satisfies the Renderer interface.
func NewHTMLRenderer(params HTMLRendererParameters) *HTMLRenderer {
// configure the rendering engine
closeTag := htmlClose
if params.Flags&UseXHTML != 0 {
closeTag = xhtmlClose
}
if params.FootnoteReturnLinkContents == "" {
// U+FE0E is VARIATION SELECTOR-15.
// It suppresses automatic emoji presentation of the preceding
// U+21A9 LEFTWARDS ARROW WITH HOOK on iOS and iPadOS.
params.FootnoteReturnLinkContents = "<span aria-label='Return'>↩\ufe0e</span>"
}
return &HTMLRenderer{
HTMLRendererParameters: params,
closeTag: closeTag,
headingIDs: make(map[string]int),
sr: NewSmartypantsRenderer(params.Flags),
}
}
func isHTMLTag(tag []byte, tagname string) bool {
found, _ := findHTMLTagPos(tag, tagname)
return found
}
// Look for a character, but ignore it when it's in any kind of quotes, it
// might be JavaScript
func skipUntilCharIgnoreQuotes(html []byte, start int, char byte) int {
inSingleQuote := false
inDoubleQuote := false
inGraveQuote := false
i := start
for i < len(html) {
switch {
case html[i] == char && !inSingleQuote && !inDoubleQuote && !inGraveQuote:
return i
case html[i] == '\'':
inSingleQuote = !inSingleQuote
case html[i] == '"':
inDoubleQuote = !inDoubleQuote
case html[i] == '`':
inGraveQuote = !inGraveQuote
}
i++
}
return start
}
func findHTMLTagPos(tag []byte, tagname string) (bool, int) {
i := 0
if i < len(tag) && tag[0] != '<' {
return false, -1
}
i++
i = skipSpace(tag, i)
if i < len(tag) && tag[i] == '/' {
i++
}
i = skipSpace(tag, i)
j := 0
for ; i < len(tag); i, j = i+1, j+1 {
if j >= len(tagname) {
break
}
if strings.ToLower(string(tag[i]))[0] != tagname[j] {
return false, -1
}
}
if i == len(tag) {
return false, -1
}
rightAngle := skipUntilCharIgnoreQuotes(tag, i, '>')
if rightAngle >= i {
return true, rightAngle
}
return false, -1
}
func skipSpace(tag []byte, i int) int {
for i < len(tag) && isspace(tag[i]) {
i++
}
return i
}
func isRelativeLink(link []byte) (yes bool) {
// a tag begin with '#'
if link[0] == '#' {
return true
}
// link begin with '/' but not '//', the second maybe a protocol relative link
if len(link) >= 2 && link[0] == '/' && link[1] != '/' {
return true
}
// only the root '/'
if len(link) == 1 && link[0] == '/' {
return true
}
// current directory : begin with "./"
if bytes.HasPrefix(link, []byte("./")) {
return true
}
// parent directory : begin with "../"
if bytes.HasPrefix(link, []byte("../")) {
return true
}
return false
}
func (r *HTMLRenderer) ensureUniqueHeadingID(id string) string {
for count, found := r.headingIDs[id]; found; count, found = r.headingIDs[id] {
tmp := fmt.Sprintf("%s-%d", id, count+1)
if _, tmpFound := r.headingIDs[tmp]; !tmpFound {
r.headingIDs[id] = count + 1
id = tmp
} else {
id = id + "-1"
}
}
if _, found := r.headingIDs[id]; !found {
r.headingIDs[id] = 0
}
return id
}
func (r *HTMLRenderer) addAbsPrefix(link []byte) []byte {
if r.AbsolutePrefix != "" && isRelativeLink(link) && link[0] != '.' {
newDest := r.AbsolutePrefix
if link[0] != '/' {
newDest += "/"
}
newDest += string(link)
return []byte(newDest)
}
return link
}
func appendLinkAttrs(attrs []string, flags HTMLFlags, link []byte) []string {
if isRelativeLink(link) {
return attrs
}
val := []string{}
if flags&NofollowLinks != 0 {
val = append(val, "nofollow")
}
if flags&NoreferrerLinks != 0 {
val = append(val, "noreferrer")
}
if flags&NoopenerLinks != 0 {
val = append(val, "noopener")
}
if flags&HrefTargetBlank != 0 {
attrs = append(attrs, "target=\"_blank\"")
}
if len(val) == 0 {
return attrs
}
attr := fmt.Sprintf("rel=%q", strings.Join(val, " "))
return append(attrs, attr)
}
func isMailto(link []byte) bool {
return bytes.HasPrefix(link, []byte("mailto:"))
}
func needSkipLink(flags HTMLFlags, dest []byte) bool {
if flags&SkipLinks != 0 {
return true
}
return flags&Safelink != 0 && !isSafeLink(dest) && !isMailto(dest)
}
func isSmartypantable(node *Node) bool {
pt := node.Parent.Type
return pt != Link && pt != CodeBlock && pt != Code
}
func appendLanguageAttr(attrs []string, info []byte) []string {
if len(info) == 0 {
return attrs
}
endOfLang := bytes.IndexAny(info, "\t ")
if endOfLang < 0 {
endOfLang = len(info)
}
return append(attrs, fmt.Sprintf("class=\"language-%s\"", info[:endOfLang]))
}
func (r *HTMLRenderer) tag(w io.Writer, name []byte, attrs []string) {
w.Write(name)
if len(attrs) > 0 {
w.Write(spaceBytes)
w.Write([]byte(strings.Join(attrs, " ")))
}
w.Write(gtBytes)
r.lastOutputLen = 1
}
func footnoteRef(prefix string, node *Node) []byte {
urlFrag := prefix + string(slugify(node.Destination))
anchor := fmt.Sprintf(`<a href="#fn:%s">%d</a>`, urlFrag, node.NoteID)
return []byte(fmt.Sprintf(`<sup class="footnote-ref" id="fnref:%s">%s</sup>`, urlFrag, anchor))
}
func footnoteItem(prefix string, slug []byte) []byte {
return []byte(fmt.Sprintf(`<li id="fn:%s%s">`, prefix, slug))
}
func footnoteReturnLink(prefix, returnLink string, slug []byte) []byte {
const format = ` <a class="footnote-return" href="#fnref:%s%s">%s</a>`
return []byte(fmt.Sprintf(format, prefix, slug, returnLink))
}
func itemOpenCR(node *Node) bool {
if node.Prev == nil {
return false
}
ld := node.Parent.ListData
return !ld.Tight && ld.ListFlags&ListTypeDefinition == 0
}
func skipParagraphTags(node *Node) bool {
grandparent := node.Parent.Parent
if grandparent == nil || grandparent.Type != List {
return false
}
tightOrTerm := grandparent.Tight || node.Parent.ListFlags&ListTypeTerm != 0
return grandparent.Type == List && tightOrTerm
}
func cellAlignment(align CellAlignFlags) string {
switch align {
case TableAlignmentLeft:
return "left"
case TableAlignmentRight:
return "right"
case TableAlignmentCenter:
return "center"
default:
return ""
}
}
func (r *HTMLRenderer) out(w io.Writer, text []byte) {
if r.disableTags > 0 {
w.Write(htmlTagRe.ReplaceAll(text, []byte{}))
} else {
w.Write(text)
}
r.lastOutputLen = len(text)
}
func (r *HTMLRenderer) cr(w io.Writer) {
if r.lastOutputLen > 0 {
r.out(w, nlBytes)
}
}
var (
nlBytes = []byte{'\n'}
gtBytes = []byte{'>'}
spaceBytes = []byte{' '}
)
var (
brTag = []byte("<br>")
brXHTMLTag = []byte("<br />")
emTag = []byte("<em>")
emCloseTag = []byte("</em>")
strongTag = []byte("<strong>")
strongCloseTag = []byte("</strong>")
delTag = []byte("<del>")
delCloseTag = []byte("</del>")
ttTag = []byte("<tt>")
ttCloseTag = []byte("</tt>")
aTag = []byte("<a")
aCloseTag = []byte("</a>")
preTag = []byte("<pre>")
preCloseTag = []byte("</pre>")
codeTag = []byte("<code>")
codeCloseTag = []byte("</code>")
pTag = []byte("<p>")
pCloseTag = []byte("</p>")
blockquoteTag = []byte("<blockquote>")
blockquoteCloseTag = []byte("</blockquote>")
hrTag = []byte("<hr>")
hrXHTMLTag = []byte("<hr />")
ulTag = []byte("<ul>")
ulCloseTag = []byte("</ul>")
olTag = []byte("<ol>")
olCloseTag = []byte("</ol>")
dlTag = []byte("<dl>")
dlCloseTag = []byte("</dl>")
liTag = []byte("<li>")
liCloseTag = []byte("</li>")
ddTag = []byte("<dd>")
ddCloseTag = []byte("</dd>")
dtTag = []byte("<dt>")
dtCloseTag = []byte("</dt>")
tableTag = []byte("<table>")
tableCloseTag = []byte("</table>")
tdTag = []byte("<td")
tdCloseTag = []byte("</td>")
thTag = []byte("<th")
thCloseTag = []byte("</th>")
theadTag = []byte("<thead>")
theadCloseTag = []byte("</thead>")
tbodyTag = []byte("<tbody>")
tbodyCloseTag = []byte("</tbody>")
trTag = []byte("<tr>")
trCloseTag = []byte("</tr>")
h1Tag = []byte("<h1")
h1CloseTag = []byte("</h1>")
h2Tag = []byte("<h2")
h2CloseTag = []byte("</h2>")
h3Tag = []byte("<h3")
h3CloseTag = []byte("</h3>")
h4Tag = []byte("<h4")
h4CloseTag = []byte("</h4>")
h5Tag = []byte("<h5")
h5CloseTag = []byte("</h5>")
h6Tag = []byte("<h6")
h6CloseTag = []byte("</h6>")
footnotesDivBytes = []byte("\n<div class=\"footnotes\">\n\n")
footnotesCloseDivBytes = []byte("\n</div>\n")
)
func headingTagsFromLevel(level int) ([]byte, []byte) {
if level <= 1 {
return h1Tag, h1CloseTag
}
switch level {
case 2:
return h2Tag, h2CloseTag
case 3:
return h3Tag, h3CloseTag
case 4:
return h4Tag, h4CloseTag
case 5:
return h5Tag, h5CloseTag
}
return h6Tag, h6CloseTag
}
func (r *HTMLRenderer) outHRTag(w io.Writer) {
if r.Flags&UseXHTML == 0 {
r.out(w, hrTag)
} else {
r.out(w, hrXHTMLTag)
}
}
// RenderNode is a default renderer of a single node of a syntax tree. For
// block nodes it will be called twice: first time with entering=true, second
// time with entering=false, so that it could know when it's working on an open
// tag and when on close. It writes the result to w.
//
// The return value is a way to tell the calling walker to adjust its walk
// pattern: e.g. it can terminate the traversal by returning Terminate. Or it
// can ask the walker to skip a subtree of this node by returning SkipChildren.
// The typical behavior is to return GoToNext, which asks for the usual
// traversal to the next node.
func (r *HTMLRenderer) RenderNode(w io.Writer, node *Node, entering bool) WalkStatus {
attrs := []string{}
switch node.Type {
case Text:
if r.Flags&Smartypants != 0 {
var tmp bytes.Buffer
escapeHTML(&tmp, node.Literal)
r.sr.Process(w, tmp.Bytes())
} else {
if node.Parent.Type == Link {
escLink(w, node.Literal)
} else {
escapeHTML(w, node.Literal)
}
}
case Softbreak:
r.cr(w)
// TODO: make it configurable via out(renderer.softbreak)
case Hardbreak:
if r.Flags&UseXHTML == 0 {
r.out(w, brTag)
} else {
r.out(w, brXHTMLTag)
}
r.cr(w)
case Emph:
if entering {
r.out(w, emTag)
} else {
r.out(w, emCloseTag)
}
case Strong:
if entering {
r.out(w, strongTag)
} else {
r.out(w, strongCloseTag)
}
case Del:
if entering {
r.out(w, delTag)
} else {
r.out(w, delCloseTag)
}
case HTMLSpan:
if r.Flags&SkipHTML != 0 {
break
}
r.out(w, node.Literal)
case Link:
// mark it but don't link it if it is not a safe link: no smartypants
dest := node.LinkData.Destination
if needSkipLink(r.Flags, dest) {
if entering {
r.out(w, ttTag)
} else {
r.out(w, ttCloseTag)
}
} else {
if entering {
dest = r.addAbsPrefix(dest)
var hrefBuf bytes.Buffer
hrefBuf.WriteString("href=\"")
escLink(&hrefBuf, dest)
hrefBuf.WriteByte('"')
attrs = append(attrs, hrefBuf.String())
if node.NoteID != 0 {
r.out(w, footnoteRef(r.FootnoteAnchorPrefix, node))
break
}
attrs = appendLinkAttrs(attrs, r.Flags, dest)
if len(node.LinkData.Title) > 0 {
var titleBuff bytes.Buffer
titleBuff.WriteString("title=\"")
escapeHTML(&titleBuff, node.LinkData.Title)
titleBuff.WriteByte('"')
attrs = append(attrs, titleBuff.String())
}
r.tag(w, aTag, attrs)
} else {
if node.NoteID != 0 {
break
}
r.out(w, aCloseTag)
}
}
case Image:
if r.Flags&SkipImages != 0 {
return SkipChildren
}
if entering {
dest := node.LinkData.Destination
dest = r.addAbsPrefix(dest)
if r.disableTags == 0 {
//if options.safe && potentiallyUnsafe(dest) {
//out(w, `<img src="" alt="`)
//} else {
r.out(w, []byte(`<img src="`))
escLink(w, dest)
r.out(w, []byte(`" alt="`))
//}
}
r.disableTags++
} else {
r.disableTags--
if r.disableTags == 0 {
if node.LinkData.Title != nil {
r.out(w, []byte(`" title="`))
escapeHTML(w, node.LinkData.Title)
}
r.out(w, []byte(`" />`))
}
}
case Code:
r.out(w, codeTag)
escapeHTML(w, node.Literal)
r.out(w, codeCloseTag)
case Document:
break
case Paragraph:
if skipParagraphTags(node) {
break
}
if entering {
// TODO: untangle this clusterfuck about when the newlines need
// to be added and when not.
if node.Prev != nil {
switch node.Prev.Type {
case HTMLBlock, List, Paragraph, Heading, CodeBlock, BlockQuote, HorizontalRule:
r.cr(w)
}
}
if node.Parent.Type == BlockQuote && node.Prev == nil {
r.cr(w)
}
r.out(w, pTag)
} else {
r.out(w, pCloseTag)
if !(node.Parent.Type == Item && node.Next == nil) {
r.cr(w)
}
}
case BlockQuote:
if entering {
r.cr(w)
r.out(w, blockquoteTag)
} else {
r.out(w, blockquoteCloseTag)
r.cr(w)
}
case HTMLBlock:
if r.Flags&SkipHTML != 0 {
break
}
r.cr(w)
r.out(w, node.Literal)
r.cr(w)
case Heading:
headingLevel := r.HTMLRendererParameters.HeadingLevelOffset + node.Level
openTag, closeTag := headingTagsFromLevel(headingLevel)
if entering {
if node.IsTitleblock {
attrs = append(attrs, `class="title"`)
}
if node.HeadingID != "" {
id := r.ensureUniqueHeadingID(node.HeadingID)
if r.HeadingIDPrefix != "" {
id = r.HeadingIDPrefix + id
}
if r.HeadingIDSuffix != "" {
id = id + r.HeadingIDSuffix
}
attrs = append(attrs, fmt.Sprintf(`id="%s"`, id))
}
r.cr(w)
r.tag(w, openTag, attrs)
} else {
r.out(w, closeTag)
if !(node.Parent.Type == Item && node.Next == nil) {
r.cr(w)
}
}
case HorizontalRule:
r.cr(w)
r.outHRTag(w)
r.cr(w)
case List:
openTag := ulTag
closeTag := ulCloseTag
if node.ListFlags&ListTypeOrdered != 0 {
openTag = olTag
closeTag = olCloseTag
}
if node.ListFlags&ListTypeDefinition != 0 {
openTag = dlTag
closeTag = dlCloseTag
}
if entering {
if node.IsFootnotesList {
r.out(w, footnotesDivBytes)
r.outHRTag(w)
r.cr(w)
}
r.cr(w)
if node.Parent.Type == Item && node.Parent.Parent.Tight {
r.cr(w)
}
r.tag(w, openTag[:len(openTag)-1], attrs)
r.cr(w)
} else {
r.out(w, closeTag)
//cr(w)
//if node.parent.Type != Item {
// cr(w)
//}
if node.Parent.Type == Item && node.Next != nil {
r.cr(w)
}
if node.Parent.Type == Document || node.Parent.Type == BlockQuote {
r.cr(w)
}
if node.IsFootnotesList {
r.out(w, footnotesCloseDivBytes)
}
}
case Item:
openTag := liTag
closeTag := liCloseTag
if node.ListFlags&ListTypeDefinition != 0 {
openTag = ddTag
closeTag = ddCloseTag
}
if node.ListFlags&ListTypeTerm != 0 {
openTag = dtTag
closeTag = dtCloseTag
}
if entering {
if itemOpenCR(node) {
r.cr(w)
}
if node.ListData.RefLink != nil {
slug := slugify(node.ListData.RefLink)
r.out(w, footnoteItem(r.FootnoteAnchorPrefix, slug))
break
}
r.out(w, openTag)
} else {
if node.ListData.RefLink != nil {
slug := slugify(node.ListData.RefLink)
if r.Flags&FootnoteReturnLinks != 0 {
r.out(w, footnoteReturnLink(r.FootnoteAnchorPrefix, r.FootnoteReturnLinkContents, slug))
}
}
r.out(w, closeTag)
r.cr(w)
}
case CodeBlock:
attrs = appendLanguageAttr(attrs, node.Info)
r.cr(w)
r.out(w, preTag)
r.tag(w, codeTag[:len(codeTag)-1], attrs)
escapeHTML(w, node.Literal)
r.out(w, codeCloseTag)
r.out(w, preCloseTag)
if node.Parent.Type != Item {
r.cr(w)
}
case Table:
if entering {
r.cr(w)
r.out(w, tableTag)
} else {
r.out(w, tableCloseTag)
r.cr(w)
}
case TableCell:
openTag := tdTag
closeTag := tdCloseTag
if node.IsHeader {
openTag = thTag
closeTag = thCloseTag
}
if entering {
align := cellAlignment(node.Align)
if align != "" {
attrs = append(attrs, fmt.Sprintf(`align="%s"`, align))
}
if node.Prev == nil {
r.cr(w)
}
r.tag(w, openTag, attrs)
} else {
r.out(w, closeTag)
r.cr(w)
}
case TableHead:
if entering {
r.cr(w)
r.out(w, theadTag)
} else {
r.out(w, theadCloseTag)
r.cr(w)
}
case TableBody:
if entering {
r.cr(w)
r.out(w, tbodyTag)
// XXX: this is to adhere to a rather silly test. Should fix test.
if node.FirstChild == nil {
r.cr(w)
}
} else {
r.out(w, tbodyCloseTag)
r.cr(w)
}
case TableRow:
if entering {
r.cr(w)
r.out(w, trTag)
} else {
r.out(w, trCloseTag)
r.cr(w)
}
default:
panic("Unknown node type " + node.Type.String())
}
return GoToNext
}
// RenderHeader writes HTML document preamble and TOC if requested.
func (r *HTMLRenderer) RenderHeader(w io.Writer, ast *Node) {
r.writeDocumentHeader(w)
if r.Flags&TOC != 0 {
r.writeTOC(w, ast)
}
}
// RenderFooter writes HTML document footer.
func (r *HTMLRenderer) RenderFooter(w io.Writer, ast *Node) {
if r.Flags&CompletePage == 0 {
return
}
io.WriteString(w, "\n</body>\n</html>\n")
}
func (r *HTMLRenderer) writeDocumentHeader(w io.Writer) {
if r.Flags&CompletePage == 0 {
return
}
ending := ""
if r.Flags&UseXHTML != 0 {
io.WriteString(w, "<!DOCTYPE html PUBLIC \"-//W3C//DTD XHTML 1.0 Transitional//EN\" ")
io.WriteString(w, "\"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd\">\n")
io.WriteString(w, "<html xmlns=\"http://www.w3.org/1999/xhtml\">\n")
ending = " /"
} else {
io.WriteString(w, "<!DOCTYPE html>\n")
io.WriteString(w, "<html>\n")
}
io.WriteString(w, "<head>\n")
io.WriteString(w, " <title>")
if r.Flags&Smartypants != 0 {
r.sr.Process(w, []byte(r.Title))
} else {
escapeHTML(w, []byte(r.Title))
}
io.WriteString(w, "</title>\n")
io.WriteString(w, " <meta name=\"GENERATOR\" content=\"Blackfriday Markdown Processor v")
io.WriteString(w, Version)
io.WriteString(w, "\"")
io.WriteString(w, ending)
io.WriteString(w, ">\n")
io.WriteString(w, " <meta charset=\"utf-8\"")
io.WriteString(w, ending)
io.WriteString(w, ">\n")
if r.CSS != "" {
io.WriteString(w, " <link rel=\"stylesheet\" type=\"text/css\" href=\"")
escapeHTML(w, []byte(r.CSS))
io.WriteString(w, "\"")
io.WriteString(w, ending)
io.WriteString(w, ">\n")
}
if r.Icon != "" {
io.WriteString(w, " <link rel=\"icon\" type=\"image/x-icon\" href=\"")
escapeHTML(w, []byte(r.Icon))
io.WriteString(w, "\"")
io.WriteString(w, ending)
io.WriteString(w, ">\n")
}
io.WriteString(w, "</head>\n")
io.WriteString(w, "<body>\n\n")
}
func (r *HTMLRenderer) writeTOC(w io.Writer, ast *Node) {
buf := bytes.Buffer{}
inHeading := false
tocLevel := 0
headingCount := 0
ast.Walk(func(node *Node, entering bool) WalkStatus {
if node.Type == Heading && !node.HeadingData.IsTitleblock {
inHeading = entering
if entering {
node.HeadingID = fmt.Sprintf("toc_%d", headingCount)
if node.Level == tocLevel {
buf.WriteString("</li>\n\n<li>")
} else if node.Level < tocLevel {
for node.Level < tocLevel {
tocLevel--
buf.WriteString("</li>\n</ul>")
}
buf.WriteString("</li>\n\n<li>")
} else {
for node.Level > tocLevel {
tocLevel++
buf.WriteString("\n<ul>\n<li>")
}
}
fmt.Fprintf(&buf, `<a href="#toc_%d">`, headingCount)
headingCount++
} else {
buf.WriteString("</a>")
}
return GoToNext
}
if inHeading {
return r.RenderNode(&buf, node, entering)
}
return GoToNext
})
for ; tocLevel > 0; tocLevel-- {
buf.WriteString("</li>\n</ul>")
}
if buf.Len() > 0 {
io.WriteString(w, "<nav>\n")
w.Write(buf.Bytes())
io.WriteString(w, "\n\n</nav>\n")
}
r.lastOutputLen = buf.Len()
}