Update markdown parsing library to github.com/gomarkdown/markdown (#944)

vendor/github.com/gomarkdown/markdown/parser/aside.go

@@ -0,0 +1,73 @@
+package parser
+
+import (
+	"bytes"
+
+	"github.com/gomarkdown/markdown/ast"
+)
+
+// returns aisde prefix length
+func (p *Parser) asidePrefix(data []byte) int {
+	i := 0
+	n := len(data)
+	for i < 3 && i < n && data[i] == ' ' {
+		i++
+	}
+	if i+1 < n && data[i] == 'A' && data[i+1] == '>' {
+		if i+2 < n && data[i+2] == ' ' {
+			return i + 3
+		}
+		return i + 2
+	}
+	return 0
+}
+
+// aside ends with at least one blank line
+// followed by something without a aside prefix
+func (p *Parser) terminateAside(data []byte, beg, end int) bool {
+	if p.isEmpty(data[beg:]) <= 0 {
+		return false
+	}
+	if end >= len(data) {
+		return true
+	}
+	return p.asidePrefix(data[end:]) == 0 && p.isEmpty(data[end:]) == 0
+}
+
+// parse a aside fragment
+func (p *Parser) aside(data []byte) int {
+	var raw bytes.Buffer
+	beg, end := 0, 0
+	// identical to quote
+	for beg < len(data) {
+		end = beg
+		// Step over whole lines, collecting them. While doing that, check for
+		// fenced code and if one's found, incorporate it altogether,
+		// irregardless of any contents inside it
+		for end < len(data) && data[end] != '\n' {
+			if p.extensions&FencedCode != 0 {
+				if i := p.fencedCodeBlock(data[end:], false); i > 0 {
+					// -1 to compensate for the extra end++ after the loop:
+					end += i - 1
+					break
+				}
+			}
+			end++
+		}
+		end = skipCharN(data, end, '\n', 1)
+		if pre := p.asidePrefix(data[beg:]); pre > 0 {
+			// skip the prefix
+			beg += pre
+		} else if p.terminateAside(data, beg, end) {
+			break
+		}
+		// this line is part of the aside
+		raw.Write(data[beg:end])
+		beg = end
+	}
+
+	block := p.addBlock(&ast.Aside{})
+	p.block(raw.Bytes())
+	p.finalize(block)
+	return end
+}