[chore/bugfix] Switch markdown from blackfriday to goldmark (#1267)

Co-authored-by: Autumn! <autumnull@posteo.net>

vendor/github.com/yuin/goldmark/parser/raw_html.go

@@ -0,0 +1,163 @@
+package parser
+
+import (
+	"bytes"
+	"regexp"
+
+	"github.com/yuin/goldmark/ast"
+	"github.com/yuin/goldmark/text"
+	"github.com/yuin/goldmark/util"
+)
+
+type rawHTMLParser struct {
+}
+
+var defaultRawHTMLParser = &rawHTMLParser{}
+
+// NewRawHTMLParser return a new InlineParser that can parse
+// inline htmls
+func NewRawHTMLParser() InlineParser {
+	return defaultRawHTMLParser
+}
+
+func (s *rawHTMLParser) Trigger() []byte {
+	return []byte{'<'}
+}
+
+func (s *rawHTMLParser) Parse(parent ast.Node, block text.Reader, pc Context) ast.Node {
+	line, _ := block.PeekLine()
+	if len(line) > 1 && util.IsAlphaNumeric(line[1]) {
+		return s.parseMultiLineRegexp(openTagRegexp, block, pc)
+	}
+	if len(line) > 2 && line[1] == '/' && util.IsAlphaNumeric(line[2]) {
+		return s.parseMultiLineRegexp(closeTagRegexp, block, pc)
+	}
+	if bytes.HasPrefix(line, openComment) {
+		return s.parseComment(block, pc)
+	}
+	if bytes.HasPrefix(line, openProcessingInstruction) {
+		return s.parseUntil(block, closeProcessingInstruction, pc)
+	}
+	if len(line) > 2 && line[1] == '!' && line[2] >= 'A' && line[2] <= 'Z' {
+		return s.parseUntil(block, closeDecl, pc)
+	}
+	if bytes.HasPrefix(line, openCDATA) {
+		return s.parseUntil(block, closeCDATA, pc)
+	}
+	return nil
+}
+
+var tagnamePattern = `([A-Za-z][A-Za-z0-9-]*)`
+
+var attributePattern = `(?:[\r\n \t]+[a-zA-Z_:][a-zA-Z0-9:._-]*(?:[\r\n \t]*=[\r\n \t]*(?:[^\"'=<>` + "`" + `\x00-\x20]+|'[^']*'|"[^"]*"))?)`
+var openTagRegexp = regexp.MustCompile("^<" + tagnamePattern + attributePattern + `*[ \t]*/?>`)
+var closeTagRegexp = regexp.MustCompile("^</" + tagnamePattern + `\s*>`)
+
+var openProcessingInstruction = []byte("<?")
+var closeProcessingInstruction = []byte("?>")
+var openCDATA = []byte("<![CDATA[")
+var closeCDATA = []byte("]]>")
+var closeDecl = []byte(">")
+var emptyComment = []byte("<!---->")
+var invalidComment1 = []byte("<!-->")
+var invalidComment2 = []byte("<!--->")
+var openComment = []byte("<!--")
+var closeComment = []byte("-->")
+var doubleHyphen = []byte("--")
+
+func (s *rawHTMLParser) parseComment(block text.Reader, pc Context) ast.Node {
+	savedLine, savedSegment := block.Position()
+	node := ast.NewRawHTML()
+	line, segment := block.PeekLine()
+	if bytes.HasPrefix(line, emptyComment) {
+		node.Segments.Append(segment.WithStop(segment.Start + len(emptyComment)))
+		block.Advance(len(emptyComment))
+		return node
+	}
+	if bytes.HasPrefix(line, invalidComment1) || bytes.HasPrefix(line, invalidComment2) {
+		return nil
+	}
+	offset := len(openComment)
+	line = line[offset:]
+	for {
+		hindex := bytes.Index(line, doubleHyphen)
+		if hindex > -1 {
+			hindex += offset
+		}
+		index := bytes.Index(line, closeComment) + offset
+		if index > -1 && hindex == index {
+			if index == 0 || len(line) < 2 || line[index-offset-1] != '-' {
+				node.Segments.Append(segment.WithStop(segment.Start + index + len(closeComment)))
+				block.Advance(index + len(closeComment))
+				return node
+			}
+		}
+		if hindex > 0 {
+			break
+		}
+		node.Segments.Append(segment)
+		block.AdvanceLine()
+		line, segment = block.PeekLine()
+		offset = 0
+		if line == nil {
+			break
+		}
+	}
+	block.SetPosition(savedLine, savedSegment)
+	return nil
+}
+
+func (s *rawHTMLParser) parseUntil(block text.Reader, closer []byte, pc Context) ast.Node {
+	savedLine, savedSegment := block.Position()
+	node := ast.NewRawHTML()
+	for {
+		line, segment := block.PeekLine()
+		if line == nil {
+			break
+		}
+		index := bytes.Index(line, closer)
+		if index > -1 {
+			node.Segments.Append(segment.WithStop(segment.Start + index + len(closer)))
+			block.Advance(index + len(closer))
+			return node
+		}
+		node.Segments.Append(segment)
+		block.AdvanceLine()
+	}
+	block.SetPosition(savedLine, savedSegment)
+	return nil
+}
+
+func (s *rawHTMLParser) parseMultiLineRegexp(reg *regexp.Regexp, block text.Reader, pc Context) ast.Node {
+	sline, ssegment := block.Position()
+	if block.Match(reg) {
+		node := ast.NewRawHTML()
+		eline, esegment := block.Position()
+		block.SetPosition(sline, ssegment)
+		for {
+			line, segment := block.PeekLine()
+			if line == nil {
+				break
+			}
+			l, _ := block.Position()
+			start := segment.Start
+			if l == sline {
+				start = ssegment.Start
+			}
+			end := segment.Stop
+			if l == eline {
+				end = esegment.Start
+			}
+
+			node.Segments.Append(text.NewSegment(start, end))
+			if l == eline {
+				block.Advance(end - start)
+				break
+			} else {
+				block.AdvanceLine()
+			}
+		}
+		return node
+	}
+	return nil
+}