mirror of
https://github.com/go-gitea/gitea
synced 2024-12-24 17:44:27 +00:00
1229 lines
25 KiB
Go
Vendored
1229 lines
25 KiB
Go
Vendored
//
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// Blackfriday Markdown Processor
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// Available at http://github.com/russross/blackfriday
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//
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// Copyright © 2011 Russ Ross <russ@russross.com>.
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// Distributed under the Simplified BSD License.
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// See README.md for details.
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//
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//
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// Functions to parse inline elements.
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//
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package blackfriday
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import (
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"bytes"
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"regexp"
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"strconv"
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)
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var (
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urlRe = `((https?|ftp):\/\/|\/)[-A-Za-z0-9+&@#\/%?=~_|!:,.;\(\)]+`
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anchorRe = regexp.MustCompile(`^(<a\shref="` + urlRe + `"(\stitle="[^"<>]+")?\s?>` + urlRe + `<\/a>)`)
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// https://www.w3.org/TR/html5/syntax.html#character-references
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// highest unicode code point in 17 planes (2^20): 1,114,112d =
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// 7 dec digits or 6 hex digits
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// named entity references can be 2-31 characters with stuff like <
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// at one end and ∳ at the other. There
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// are also sometimes numbers at the end, although this isn't inherent
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// in the specification; there are never numbers anywhere else in
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// current character references, though; see ¾ and ▒, etc.
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// https://www.w3.org/TR/html5/syntax.html#named-character-references
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//
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// entity := "&" (named group | number ref) ";"
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// named group := [a-zA-Z]{2,31}[0-9]{0,2}
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// number ref := "#" (dec ref | hex ref)
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// dec ref := [0-9]{1,7}
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// hex ref := ("x" | "X") [0-9a-fA-F]{1,6}
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htmlEntityRe = regexp.MustCompile(`&([a-zA-Z]{2,31}[0-9]{0,2}|#([0-9]{1,7}|[xX][0-9a-fA-F]{1,6}));`)
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)
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// Functions to parse text within a block
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// Each function returns the number of chars taken care of
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// data is the complete block being rendered
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// offset is the number of valid chars before the current cursor
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func (p *Markdown) inline(currBlock *Node, data []byte) {
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// handlers might call us recursively: enforce a maximum depth
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if p.nesting >= p.maxNesting || len(data) == 0 {
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return
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}
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p.nesting++
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beg, end := 0, 0
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for end < len(data) {
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handler := p.inlineCallback[data[end]]
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if handler != nil {
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if consumed, node := handler(p, data, end); consumed == 0 {
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// No action from the callback.
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end++
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} else {
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// Copy inactive chars into the output.
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currBlock.AppendChild(text(data[beg:end]))
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if node != nil {
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currBlock.AppendChild(node)
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}
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// Skip past whatever the callback used.
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beg = end + consumed
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end = beg
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}
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} else {
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end++
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}
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}
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if beg < len(data) {
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if data[end-1] == '\n' {
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end--
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}
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currBlock.AppendChild(text(data[beg:end]))
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}
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p.nesting--
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}
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// single and double emphasis parsing
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func emphasis(p *Markdown, data []byte, offset int) (int, *Node) {
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data = data[offset:]
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c := data[0]
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if len(data) > 2 && data[1] != c {
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// whitespace cannot follow an opening emphasis;
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// strikethrough only takes two characters '~~'
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if c == '~' || isspace(data[1]) {
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return 0, nil
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}
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ret, node := helperEmphasis(p, data[1:], c)
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if ret == 0 {
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return 0, nil
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}
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return ret + 1, node
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}
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if len(data) > 3 && data[1] == c && data[2] != c {
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if isspace(data[2]) {
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return 0, nil
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}
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ret, node := helperDoubleEmphasis(p, data[2:], c)
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if ret == 0 {
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return 0, nil
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}
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return ret + 2, node
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}
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if len(data) > 4 && data[1] == c && data[2] == c && data[3] != c {
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if c == '~' || isspace(data[3]) {
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return 0, nil
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}
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ret, node := helperTripleEmphasis(p, data, 3, c)
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if ret == 0 {
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return 0, nil
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}
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return ret + 3, node
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}
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return 0, nil
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}
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func codeSpan(p *Markdown, data []byte, offset int) (int, *Node) {
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data = data[offset:]
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nb := 0
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// count the number of backticks in the delimiter
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for nb < len(data) && data[nb] == '`' {
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nb++
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}
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// find the next delimiter
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i, end := 0, 0
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for end = nb; end < len(data) && i < nb; end++ {
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if data[end] == '`' {
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i++
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} else {
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i = 0
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}
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}
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// no matching delimiter?
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if i < nb && end >= len(data) {
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return 0, nil
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}
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// trim outside whitespace
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fBegin := nb
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for fBegin < end && data[fBegin] == ' ' {
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fBegin++
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}
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fEnd := end - nb
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for fEnd > fBegin && data[fEnd-1] == ' ' {
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fEnd--
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}
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// render the code span
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if fBegin != fEnd {
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code := NewNode(Code)
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code.Literal = data[fBegin:fEnd]
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return end, code
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}
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return end, nil
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}
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// newline preceded by two spaces becomes <br>
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func maybeLineBreak(p *Markdown, data []byte, offset int) (int, *Node) {
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origOffset := offset
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for offset < len(data) && data[offset] == ' ' {
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offset++
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}
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if offset < len(data) && data[offset] == '\n' {
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if offset-origOffset >= 2 {
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return offset - origOffset + 1, NewNode(Hardbreak)
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}
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return offset - origOffset, nil
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}
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return 0, nil
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}
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// newline without two spaces works when HardLineBreak is enabled
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func lineBreak(p *Markdown, data []byte, offset int) (int, *Node) {
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if p.extensions&HardLineBreak != 0 {
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return 1, NewNode(Hardbreak)
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}
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return 0, nil
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}
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type linkType int
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const (
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linkNormal linkType = iota
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linkImg
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linkDeferredFootnote
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linkInlineFootnote
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)
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func isReferenceStyleLink(data []byte, pos int, t linkType) bool {
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if t == linkDeferredFootnote {
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return false
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}
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return pos < len(data)-1 && data[pos] == '[' && data[pos+1] != '^'
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}
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func maybeImage(p *Markdown, data []byte, offset int) (int, *Node) {
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if offset < len(data)-1 && data[offset+1] == '[' {
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return link(p, data, offset)
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}
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return 0, nil
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}
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func maybeInlineFootnote(p *Markdown, data []byte, offset int) (int, *Node) {
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if offset < len(data)-1 && data[offset+1] == '[' {
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return link(p, data, offset)
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}
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return 0, nil
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}
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// '[': parse a link or an image or a footnote
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func link(p *Markdown, data []byte, offset int) (int, *Node) {
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// no links allowed inside regular links, footnote, and deferred footnotes
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if p.insideLink && (offset > 0 && data[offset-1] == '[' || len(data)-1 > offset && data[offset+1] == '^') {
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return 0, nil
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}
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var t linkType
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switch {
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// special case: ![^text] == deferred footnote (that follows something with
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// an exclamation point)
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case p.extensions&Footnotes != 0 && len(data)-1 > offset && data[offset+1] == '^':
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t = linkDeferredFootnote
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// ![alt] == image
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case offset >= 0 && data[offset] == '!':
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t = linkImg
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offset++
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// ^[text] == inline footnote
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// [^refId] == deferred footnote
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case p.extensions&Footnotes != 0:
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if offset >= 0 && data[offset] == '^' {
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t = linkInlineFootnote
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offset++
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} else if len(data)-1 > offset && data[offset+1] == '^' {
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t = linkDeferredFootnote
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}
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// [text] == regular link
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default:
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t = linkNormal
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}
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data = data[offset:]
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var (
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i = 1
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noteID int
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title, link, altContent []byte
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textHasNl = false
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)
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if t == linkDeferredFootnote {
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i++
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}
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// look for the matching closing bracket
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for level := 1; level > 0 && i < len(data); i++ {
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switch {
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case data[i] == '\n':
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textHasNl = true
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case isBackslashEscaped(data, i):
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continue
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case data[i] == '[':
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level++
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case data[i] == ']':
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level--
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if level <= 0 {
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i-- // compensate for extra i++ in for loop
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}
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}
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}
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if i >= len(data) {
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return 0, nil
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}
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txtE := i
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i++
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var footnoteNode *Node
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// skip any amount of whitespace or newline
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// (this is much more lax than original markdown syntax)
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for i < len(data) && isspace(data[i]) {
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i++
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}
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// inline style link
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switch {
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case i < len(data) && data[i] == '(':
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// skip initial whitespace
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i++
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for i < len(data) && isspace(data[i]) {
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i++
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}
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linkB := i
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// look for link end: ' " )
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findlinkend:
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for i < len(data) {
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switch {
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case data[i] == '\\':
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i += 2
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case data[i] == ')' || data[i] == '\'' || data[i] == '"':
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break findlinkend
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default:
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i++
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}
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}
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if i >= len(data) {
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return 0, nil
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}
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linkE := i
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// look for title end if present
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titleB, titleE := 0, 0
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if data[i] == '\'' || data[i] == '"' {
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i++
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titleB = i
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findtitleend:
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for i < len(data) {
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switch {
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case data[i] == '\\':
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i += 2
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case data[i] == ')':
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break findtitleend
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default:
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i++
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}
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}
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if i >= len(data) {
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return 0, nil
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}
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// skip whitespace after title
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titleE = i - 1
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for titleE > titleB && isspace(data[titleE]) {
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titleE--
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}
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// check for closing quote presence
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if data[titleE] != '\'' && data[titleE] != '"' {
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titleB, titleE = 0, 0
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linkE = i
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}
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}
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// remove whitespace at the end of the link
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for linkE > linkB && isspace(data[linkE-1]) {
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linkE--
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}
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// remove optional angle brackets around the link
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if data[linkB] == '<' {
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linkB++
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}
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if data[linkE-1] == '>' {
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linkE--
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}
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// build escaped link and title
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if linkE > linkB {
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link = data[linkB:linkE]
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}
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if titleE > titleB {
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title = data[titleB:titleE]
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}
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i++
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// reference style link
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case isReferenceStyleLink(data, i, t):
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var id []byte
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altContentConsidered := false
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// look for the id
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i++
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linkB := i
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for i < len(data) && data[i] != ']' {
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i++
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}
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if i >= len(data) {
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return 0, nil
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}
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linkE := i
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// find the reference
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if linkB == linkE {
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if textHasNl {
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var b bytes.Buffer
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for j := 1; j < txtE; j++ {
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switch {
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case data[j] != '\n':
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b.WriteByte(data[j])
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case data[j-1] != ' ':
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b.WriteByte(' ')
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}
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}
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id = b.Bytes()
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} else {
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id = data[1:txtE]
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altContentConsidered = true
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}
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} else {
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id = data[linkB:linkE]
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}
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// find the reference with matching id
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lr, ok := p.getRef(string(id))
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if !ok {
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return 0, nil
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}
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// keep link and title from reference
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link = lr.link
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title = lr.title
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if altContentConsidered {
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altContent = lr.text
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}
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i++
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// shortcut reference style link or reference or inline footnote
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default:
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var id []byte
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// craft the id
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if textHasNl {
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var b bytes.Buffer
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for j := 1; j < txtE; j++ {
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switch {
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case data[j] != '\n':
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b.WriteByte(data[j])
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case data[j-1] != ' ':
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b.WriteByte(' ')
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}
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}
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id = b.Bytes()
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} else {
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if t == linkDeferredFootnote {
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id = data[2:txtE] // get rid of the ^
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} else {
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id = data[1:txtE]
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}
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}
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footnoteNode = NewNode(Item)
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if t == linkInlineFootnote {
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// create a new reference
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noteID = len(p.notes) + 1
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var fragment []byte
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if len(id) > 0 {
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if len(id) < 16 {
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fragment = make([]byte, len(id))
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} else {
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fragment = make([]byte, 16)
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}
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copy(fragment, slugify(id))
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} else {
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fragment = append([]byte("footnote-"), []byte(strconv.Itoa(noteID))...)
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}
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ref := &reference{
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noteID: noteID,
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hasBlock: false,
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link: fragment,
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title: id,
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footnote: footnoteNode,
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}
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p.notes = append(p.notes, ref)
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link = ref.link
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title = ref.title
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} else {
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// find the reference with matching id
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lr, ok := p.getRef(string(id))
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if !ok {
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return 0, nil
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}
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|
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if t == linkDeferredFootnote {
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lr.noteID = len(p.notes) + 1
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lr.footnote = footnoteNode
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p.notes = append(p.notes, lr)
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}
|
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// keep link and title from reference
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link = lr.link
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// if inline footnote, title == footnote contents
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title = lr.title
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noteID = lr.noteID
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}
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// rewind the whitespace
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i = txtE + 1
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}
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var uLink []byte
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if t == linkNormal || t == linkImg {
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if len(link) > 0 {
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var uLinkBuf bytes.Buffer
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unescapeText(&uLinkBuf, link)
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uLink = uLinkBuf.Bytes()
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}
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// links need something to click on and somewhere to go
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if len(uLink) == 0 || (t == linkNormal && txtE <= 1) {
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return 0, nil
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}
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}
|
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|
|
// call the relevant rendering function
|
|
var linkNode *Node
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switch t {
|
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case linkNormal:
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linkNode = NewNode(Link)
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linkNode.Destination = normalizeURI(uLink)
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linkNode.Title = title
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if len(altContent) > 0 {
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linkNode.AppendChild(text(altContent))
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} else {
|
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// links cannot contain other links, so turn off link parsing
|
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// temporarily and recurse
|
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insideLink := p.insideLink
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p.insideLink = true
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p.inline(linkNode, data[1:txtE])
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p.insideLink = insideLink
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}
|
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|
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case linkImg:
|
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linkNode = NewNode(Image)
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linkNode.Destination = uLink
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linkNode.Title = title
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linkNode.AppendChild(text(data[1:txtE]))
|
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i++
|
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|
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case linkInlineFootnote, linkDeferredFootnote:
|
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linkNode = NewNode(Link)
|
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linkNode.Destination = link
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linkNode.Title = title
|
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linkNode.NoteID = noteID
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linkNode.Footnote = footnoteNode
|
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if t == linkInlineFootnote {
|
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i++
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}
|
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|
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default:
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return 0, nil
|
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}
|
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|
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return i, linkNode
|
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}
|
|
|
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func (p *Markdown) inlineHTMLComment(data []byte) int {
|
|
if len(data) < 5 {
|
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return 0
|
|
}
|
|
if data[0] != '<' || data[1] != '!' || data[2] != '-' || data[3] != '-' {
|
|
return 0
|
|
}
|
|
i := 5
|
|
// scan for an end-of-comment marker, across lines if necessary
|
|
for i < len(data) && !(data[i-2] == '-' && data[i-1] == '-' && data[i] == '>') {
|
|
i++
|
|
}
|
|
// no end-of-comment marker
|
|
if i >= len(data) {
|
|
return 0
|
|
}
|
|
return i + 1
|
|
}
|
|
|
|
func stripMailto(link []byte) []byte {
|
|
if bytes.HasPrefix(link, []byte("mailto://")) {
|
|
return link[9:]
|
|
} else if bytes.HasPrefix(link, []byte("mailto:")) {
|
|
return link[7:]
|
|
} else {
|
|
return link
|
|
}
|
|
}
|
|
|
|
// autolinkType specifies a kind of autolink that gets detected.
|
|
type autolinkType int
|
|
|
|
// These are the possible flag values for the autolink renderer.
|
|
const (
|
|
notAutolink autolinkType = iota
|
|
normalAutolink
|
|
emailAutolink
|
|
)
|
|
|
|
// '<' when tags or autolinks are allowed
|
|
func leftAngle(p *Markdown, data []byte, offset int) (int, *Node) {
|
|
data = data[offset:]
|
|
altype, end := tagLength(data)
|
|
if size := p.inlineHTMLComment(data); size > 0 {
|
|
end = size
|
|
}
|
|
if end > 2 {
|
|
if altype != notAutolink {
|
|
var uLink bytes.Buffer
|
|
unescapeText(&uLink, data[1:end+1-2])
|
|
if uLink.Len() > 0 {
|
|
link := uLink.Bytes()
|
|
node := NewNode(Link)
|
|
node.Destination = link
|
|
if altype == emailAutolink {
|
|
node.Destination = append([]byte("mailto:"), link...)
|
|
}
|
|
node.AppendChild(text(stripMailto(link)))
|
|
return end, node
|
|
}
|
|
} else {
|
|
htmlTag := NewNode(HTMLSpan)
|
|
htmlTag.Literal = data[:end]
|
|
return end, htmlTag
|
|
}
|
|
}
|
|
|
|
return end, nil
|
|
}
|
|
|
|
// '\\' backslash escape
|
|
var escapeChars = []byte("\\`*_{}[]()#+-.!:|&<>~")
|
|
|
|
func escape(p *Markdown, data []byte, offset int) (int, *Node) {
|
|
data = data[offset:]
|
|
|
|
if len(data) > 1 {
|
|
if p.extensions&BackslashLineBreak != 0 && data[1] == '\n' {
|
|
return 2, NewNode(Hardbreak)
|
|
}
|
|
if bytes.IndexByte(escapeChars, data[1]) < 0 {
|
|
return 0, nil
|
|
}
|
|
|
|
return 2, text(data[1:2])
|
|
}
|
|
|
|
return 2, nil
|
|
}
|
|
|
|
func unescapeText(ob *bytes.Buffer, src []byte) {
|
|
i := 0
|
|
for i < len(src) {
|
|
org := i
|
|
for i < len(src) && src[i] != '\\' {
|
|
i++
|
|
}
|
|
|
|
if i > org {
|
|
ob.Write(src[org:i])
|
|
}
|
|
|
|
if i+1 >= len(src) {
|
|
break
|
|
}
|
|
|
|
ob.WriteByte(src[i+1])
|
|
i += 2
|
|
}
|
|
}
|
|
|
|
// '&' escaped when it doesn't belong to an entity
|
|
// valid entities are assumed to be anything matching &#?[A-Za-z0-9]+;
|
|
func entity(p *Markdown, data []byte, offset int) (int, *Node) {
|
|
data = data[offset:]
|
|
|
|
end := 1
|
|
|
|
if end < len(data) && data[end] == '#' {
|
|
end++
|
|
}
|
|
|
|
for end < len(data) && isalnum(data[end]) {
|
|
end++
|
|
}
|
|
|
|
if end < len(data) && data[end] == ';' {
|
|
end++ // real entity
|
|
} else {
|
|
return 0, nil // lone '&'
|
|
}
|
|
|
|
ent := data[:end]
|
|
// undo & escaping or it will be converted to &amp; by another
|
|
// escaper in the renderer
|
|
if bytes.Equal(ent, []byte("&")) {
|
|
ent = []byte{'&'}
|
|
}
|
|
|
|
return end, text(ent)
|
|
}
|
|
|
|
func linkEndsWithEntity(data []byte, linkEnd int) bool {
|
|
entityRanges := htmlEntityRe.FindAllIndex(data[:linkEnd], -1)
|
|
return entityRanges != nil && entityRanges[len(entityRanges)-1][1] == linkEnd
|
|
}
|
|
|
|
// hasPrefixCaseInsensitive is a custom implementation of
|
|
// strings.HasPrefix(strings.ToLower(s), prefix)
|
|
// we rolled our own because ToLower pulls in a huge machinery of lowercasing
|
|
// anything from Unicode and that's very slow. Since this func will only be
|
|
// used on ASCII protocol prefixes, we can take shortcuts.
|
|
func hasPrefixCaseInsensitive(s, prefix []byte) bool {
|
|
if len(s) < len(prefix) {
|
|
return false
|
|
}
|
|
delta := byte('a' - 'A')
|
|
for i, b := range prefix {
|
|
if b != s[i] && b != s[i]+delta {
|
|
return false
|
|
}
|
|
}
|
|
return true
|
|
}
|
|
|
|
var protocolPrefixes = [][]byte{
|
|
[]byte("http://"),
|
|
[]byte("https://"),
|
|
[]byte("ftp://"),
|
|
[]byte("file://"),
|
|
[]byte("mailto:"),
|
|
}
|
|
|
|
const shortestPrefix = 6 // len("ftp://"), the shortest of the above
|
|
|
|
func maybeAutoLink(p *Markdown, data []byte, offset int) (int, *Node) {
|
|
// quick check to rule out most false hits
|
|
if p.insideLink || len(data) < offset+shortestPrefix {
|
|
return 0, nil
|
|
}
|
|
for _, prefix := range protocolPrefixes {
|
|
endOfHead := offset + 8 // 8 is the len() of the longest prefix
|
|
if endOfHead > len(data) {
|
|
endOfHead = len(data)
|
|
}
|
|
if hasPrefixCaseInsensitive(data[offset:endOfHead], prefix) {
|
|
return autoLink(p, data, offset)
|
|
}
|
|
}
|
|
return 0, nil
|
|
}
|
|
|
|
func autoLink(p *Markdown, data []byte, offset int) (int, *Node) {
|
|
// Now a more expensive check to see if we're not inside an anchor element
|
|
anchorStart := offset
|
|
offsetFromAnchor := 0
|
|
for anchorStart > 0 && data[anchorStart] != '<' {
|
|
anchorStart--
|
|
offsetFromAnchor++
|
|
}
|
|
|
|
anchorStr := anchorRe.Find(data[anchorStart:])
|
|
if anchorStr != nil {
|
|
anchorClose := NewNode(HTMLSpan)
|
|
anchorClose.Literal = anchorStr[offsetFromAnchor:]
|
|
return len(anchorStr) - offsetFromAnchor, anchorClose
|
|
}
|
|
|
|
// scan backward for a word boundary
|
|
rewind := 0
|
|
for offset-rewind > 0 && rewind <= 7 && isletter(data[offset-rewind-1]) {
|
|
rewind++
|
|
}
|
|
if rewind > 6 { // longest supported protocol is "mailto" which has 6 letters
|
|
return 0, nil
|
|
}
|
|
|
|
origData := data
|
|
data = data[offset-rewind:]
|
|
|
|
if !isSafeLink(data) {
|
|
return 0, nil
|
|
}
|
|
|
|
linkEnd := 0
|
|
for linkEnd < len(data) && !isEndOfLink(data[linkEnd]) {
|
|
linkEnd++
|
|
}
|
|
|
|
// Skip punctuation at the end of the link
|
|
if (data[linkEnd-1] == '.' || data[linkEnd-1] == ',') && data[linkEnd-2] != '\\' {
|
|
linkEnd--
|
|
}
|
|
|
|
// But don't skip semicolon if it's a part of escaped entity:
|
|
if data[linkEnd-1] == ';' && data[linkEnd-2] != '\\' && !linkEndsWithEntity(data, linkEnd) {
|
|
linkEnd--
|
|
}
|
|
|
|
// See if the link finishes with a punctuation sign that can be closed.
|
|
var copen byte
|
|
switch data[linkEnd-1] {
|
|
case '"':
|
|
copen = '"'
|
|
case '\'':
|
|
copen = '\''
|
|
case ')':
|
|
copen = '('
|
|
case ']':
|
|
copen = '['
|
|
case '}':
|
|
copen = '{'
|
|
default:
|
|
copen = 0
|
|
}
|
|
|
|
if copen != 0 {
|
|
bufEnd := offset - rewind + linkEnd - 2
|
|
|
|
openDelim := 1
|
|
|
|
/* Try to close the final punctuation sign in this same line;
|
|
* if we managed to close it outside of the URL, that means that it's
|
|
* not part of the URL. If it closes inside the URL, that means it
|
|
* is part of the URL.
|
|
*
|
|
* Examples:
|
|
*
|
|
* foo http://www.pokemon.com/Pikachu_(Electric) bar
|
|
* => http://www.pokemon.com/Pikachu_(Electric)
|
|
*
|
|
* foo (http://www.pokemon.com/Pikachu_(Electric)) bar
|
|
* => http://www.pokemon.com/Pikachu_(Electric)
|
|
*
|
|
* foo http://www.pokemon.com/Pikachu_(Electric)) bar
|
|
* => http://www.pokemon.com/Pikachu_(Electric))
|
|
*
|
|
* (foo http://www.pokemon.com/Pikachu_(Electric)) bar
|
|
* => foo http://www.pokemon.com/Pikachu_(Electric)
|
|
*/
|
|
|
|
for bufEnd >= 0 && origData[bufEnd] != '\n' && openDelim != 0 {
|
|
if origData[bufEnd] == data[linkEnd-1] {
|
|
openDelim++
|
|
}
|
|
|
|
if origData[bufEnd] == copen {
|
|
openDelim--
|
|
}
|
|
|
|
bufEnd--
|
|
}
|
|
|
|
if openDelim == 0 {
|
|
linkEnd--
|
|
}
|
|
}
|
|
|
|
var uLink bytes.Buffer
|
|
unescapeText(&uLink, data[:linkEnd])
|
|
|
|
if uLink.Len() > 0 {
|
|
node := NewNode(Link)
|
|
node.Destination = uLink.Bytes()
|
|
node.AppendChild(text(uLink.Bytes()))
|
|
return linkEnd, node
|
|
}
|
|
|
|
return linkEnd, nil
|
|
}
|
|
|
|
func isEndOfLink(char byte) bool {
|
|
return isspace(char) || char == '<'
|
|
}
|
|
|
|
var validUris = [][]byte{[]byte("http://"), []byte("https://"), []byte("ftp://"), []byte("mailto://")}
|
|
var validPaths = [][]byte{[]byte("/"), []byte("./"), []byte("../")}
|
|
|
|
func isSafeLink(link []byte) bool {
|
|
for _, path := range validPaths {
|
|
if len(link) >= len(path) && bytes.Equal(link[:len(path)], path) {
|
|
if len(link) == len(path) {
|
|
return true
|
|
} else if isalnum(link[len(path)]) {
|
|
return true
|
|
}
|
|
}
|
|
}
|
|
|
|
for _, prefix := range validUris {
|
|
// TODO: handle unicode here
|
|
// case-insensitive prefix test
|
|
if len(link) > len(prefix) && bytes.Equal(bytes.ToLower(link[:len(prefix)]), prefix) && isalnum(link[len(prefix)]) {
|
|
return true
|
|
}
|
|
}
|
|
|
|
return false
|
|
}
|
|
|
|
// return the length of the given tag, or 0 is it's not valid
|
|
func tagLength(data []byte) (autolink autolinkType, end int) {
|
|
var i, j int
|
|
|
|
// a valid tag can't be shorter than 3 chars
|
|
if len(data) < 3 {
|
|
return notAutolink, 0
|
|
}
|
|
|
|
// begins with a '<' optionally followed by '/', followed by letter or number
|
|
if data[0] != '<' {
|
|
return notAutolink, 0
|
|
}
|
|
if data[1] == '/' {
|
|
i = 2
|
|
} else {
|
|
i = 1
|
|
}
|
|
|
|
if !isalnum(data[i]) {
|
|
return notAutolink, 0
|
|
}
|
|
|
|
// scheme test
|
|
autolink = notAutolink
|
|
|
|
// try to find the beginning of an URI
|
|
for i < len(data) && (isalnum(data[i]) || data[i] == '.' || data[i] == '+' || data[i] == '-') {
|
|
i++
|
|
}
|
|
|
|
if i > 1 && i < len(data) && data[i] == '@' {
|
|
if j = isMailtoAutoLink(data[i:]); j != 0 {
|
|
return emailAutolink, i + j
|
|
}
|
|
}
|
|
|
|
if i > 2 && i < len(data) && data[i] == ':' {
|
|
autolink = normalAutolink
|
|
i++
|
|
}
|
|
|
|
// complete autolink test: no whitespace or ' or "
|
|
switch {
|
|
case i >= len(data):
|
|
autolink = notAutolink
|
|
case autolink != notAutolink:
|
|
j = i
|
|
|
|
for i < len(data) {
|
|
if data[i] == '\\' {
|
|
i += 2
|
|
} else if data[i] == '>' || data[i] == '\'' || data[i] == '"' || isspace(data[i]) {
|
|
break
|
|
} else {
|
|
i++
|
|
}
|
|
|
|
}
|
|
|
|
if i >= len(data) {
|
|
return autolink, 0
|
|
}
|
|
if i > j && data[i] == '>' {
|
|
return autolink, i + 1
|
|
}
|
|
|
|
// one of the forbidden chars has been found
|
|
autolink = notAutolink
|
|
}
|
|
i += bytes.IndexByte(data[i:], '>')
|
|
if i < 0 {
|
|
return autolink, 0
|
|
}
|
|
return autolink, i + 1
|
|
}
|
|
|
|
// look for the address part of a mail autolink and '>'
|
|
// this is less strict than the original markdown e-mail address matching
|
|
func isMailtoAutoLink(data []byte) int {
|
|
nb := 0
|
|
|
|
// address is assumed to be: [-@._a-zA-Z0-9]+ with exactly one '@'
|
|
for i := 0; i < len(data); i++ {
|
|
if isalnum(data[i]) {
|
|
continue
|
|
}
|
|
|
|
switch data[i] {
|
|
case '@':
|
|
nb++
|
|
|
|
case '-', '.', '_':
|
|
break
|
|
|
|
case '>':
|
|
if nb == 1 {
|
|
return i + 1
|
|
}
|
|
return 0
|
|
default:
|
|
return 0
|
|
}
|
|
}
|
|
|
|
return 0
|
|
}
|
|
|
|
// look for the next emph char, skipping other constructs
|
|
func helperFindEmphChar(data []byte, c byte) int {
|
|
i := 0
|
|
|
|
for i < len(data) {
|
|
for i < len(data) && data[i] != c && data[i] != '`' && data[i] != '[' {
|
|
i++
|
|
}
|
|
if i >= len(data) {
|
|
return 0
|
|
}
|
|
// do not count escaped chars
|
|
if i != 0 && data[i-1] == '\\' {
|
|
i++
|
|
continue
|
|
}
|
|
if data[i] == c {
|
|
return i
|
|
}
|
|
|
|
if data[i] == '`' {
|
|
// skip a code span
|
|
tmpI := 0
|
|
i++
|
|
for i < len(data) && data[i] != '`' {
|
|
if tmpI == 0 && data[i] == c {
|
|
tmpI = i
|
|
}
|
|
i++
|
|
}
|
|
if i >= len(data) {
|
|
return tmpI
|
|
}
|
|
i++
|
|
} else if data[i] == '[' {
|
|
// skip a link
|
|
tmpI := 0
|
|
i++
|
|
for i < len(data) && data[i] != ']' {
|
|
if tmpI == 0 && data[i] == c {
|
|
tmpI = i
|
|
}
|
|
i++
|
|
}
|
|
i++
|
|
for i < len(data) && (data[i] == ' ' || data[i] == '\n') {
|
|
i++
|
|
}
|
|
if i >= len(data) {
|
|
return tmpI
|
|
}
|
|
if data[i] != '[' && data[i] != '(' { // not a link
|
|
if tmpI > 0 {
|
|
return tmpI
|
|
}
|
|
continue
|
|
}
|
|
cc := data[i]
|
|
i++
|
|
for i < len(data) && data[i] != cc {
|
|
if tmpI == 0 && data[i] == c {
|
|
return i
|
|
}
|
|
i++
|
|
}
|
|
if i >= len(data) {
|
|
return tmpI
|
|
}
|
|
i++
|
|
}
|
|
}
|
|
return 0
|
|
}
|
|
|
|
func helperEmphasis(p *Markdown, data []byte, c byte) (int, *Node) {
|
|
i := 0
|
|
|
|
// skip one symbol if coming from emph3
|
|
if len(data) > 1 && data[0] == c && data[1] == c {
|
|
i = 1
|
|
}
|
|
|
|
for i < len(data) {
|
|
length := helperFindEmphChar(data[i:], c)
|
|
if length == 0 {
|
|
return 0, nil
|
|
}
|
|
i += length
|
|
if i >= len(data) {
|
|
return 0, nil
|
|
}
|
|
|
|
if i+1 < len(data) && data[i+1] == c {
|
|
i++
|
|
continue
|
|
}
|
|
|
|
if data[i] == c && !isspace(data[i-1]) {
|
|
|
|
if p.extensions&NoIntraEmphasis != 0 {
|
|
if !(i+1 == len(data) || isspace(data[i+1]) || ispunct(data[i+1])) {
|
|
continue
|
|
}
|
|
}
|
|
|
|
emph := NewNode(Emph)
|
|
p.inline(emph, data[:i])
|
|
return i + 1, emph
|
|
}
|
|
}
|
|
|
|
return 0, nil
|
|
}
|
|
|
|
func helperDoubleEmphasis(p *Markdown, data []byte, c byte) (int, *Node) {
|
|
i := 0
|
|
|
|
for i < len(data) {
|
|
length := helperFindEmphChar(data[i:], c)
|
|
if length == 0 {
|
|
return 0, nil
|
|
}
|
|
i += length
|
|
|
|
if i+1 < len(data) && data[i] == c && data[i+1] == c && i > 0 && !isspace(data[i-1]) {
|
|
nodeType := Strong
|
|
if c == '~' {
|
|
nodeType = Del
|
|
}
|
|
node := NewNode(nodeType)
|
|
p.inline(node, data[:i])
|
|
return i + 2, node
|
|
}
|
|
i++
|
|
}
|
|
return 0, nil
|
|
}
|
|
|
|
func helperTripleEmphasis(p *Markdown, data []byte, offset int, c byte) (int, *Node) {
|
|
i := 0
|
|
origData := data
|
|
data = data[offset:]
|
|
|
|
for i < len(data) {
|
|
length := helperFindEmphChar(data[i:], c)
|
|
if length == 0 {
|
|
return 0, nil
|
|
}
|
|
i += length
|
|
|
|
// skip whitespace preceded symbols
|
|
if data[i] != c || isspace(data[i-1]) {
|
|
continue
|
|
}
|
|
|
|
switch {
|
|
case i+2 < len(data) && data[i+1] == c && data[i+2] == c:
|
|
// triple symbol found
|
|
strong := NewNode(Strong)
|
|
em := NewNode(Emph)
|
|
strong.AppendChild(em)
|
|
p.inline(em, data[:i])
|
|
return i + 3, strong
|
|
case (i+1 < len(data) && data[i+1] == c):
|
|
// double symbol found, hand over to emph1
|
|
length, node := helperEmphasis(p, origData[offset-2:], c)
|
|
if length == 0 {
|
|
return 0, nil
|
|
}
|
|
return length - 2, node
|
|
default:
|
|
// single symbol found, hand over to emph2
|
|
length, node := helperDoubleEmphasis(p, origData[offset-1:], c)
|
|
if length == 0 {
|
|
return 0, nil
|
|
}
|
|
return length - 1, node
|
|
}
|
|
}
|
|
return 0, nil
|
|
}
|
|
|
|
func text(s []byte) *Node {
|
|
node := NewNode(Text)
|
|
node.Literal = s
|
|
return node
|
|
}
|
|
|
|
func normalizeURI(s []byte) []byte {
|
|
return s // TODO: implement
|
|
}
|