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

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

@@ -0,0 +1,119 @@
+package parser
+
+import (
+	"bytes"
+
+	"github.com/gomarkdown/markdown/ast"
+)
+
+// sFigureLine checks if there's a figure line (e.g., !--- ) at the beginning of data,
+// and returns the end index if so, or 0 otherwise.
+func sFigureLine(data []byte, oldmarker string) (end int, marker string) {
+	i, size := 0, 0
+
+	n := len(data)
+	// skip up to three spaces
+	for i < n && i < 3 && data[i] == ' ' {
+		i++
+	}
+
+	// check for the marker characters: !
+	if i+1 >= n {
+		return 0, ""
+	}
+	if data[i] != '!' || data[i+1] != '-' {
+		return 0, ""
+	}
+	i++
+
+	c := data[i] // i.e. the -
+
+	// the whole line must be the same char or whitespace
+	for i < n && data[i] == c {
+		size++
+		i++
+	}
+
+	// the marker char must occur at least 3 times
+	if size < 3 {
+		return 0, ""
+	}
+	marker = string(data[i-size : i])
+
+	// if this is the end marker, it must match the beginning marker
+	if oldmarker != "" && marker != oldmarker {
+		return 0, ""
+	}
+
+	// there is no syntax modifier although it might be an idea to re-use this space for something?
+
+	i = skipChar(data, i, ' ')
+	if i >= n || data[i] != '\n' {
+		if i == n {
+			return i, marker
+		}
+		return 0, ""
+	}
+	return i + 1, marker // Take newline into account.
+}
+
+// figureBlock returns the end index if data contains a figure block at the beginning,
+// or 0 otherwise. It writes to out if doRender is true, otherwise it has no side effects.
+// If doRender is true, a final newline is mandatory to recognize the figure block.
+func (p *Parser) figureBlock(data []byte, doRender bool) int {
+	beg, marker := sFigureLine(data, "")
+	if beg == 0 || beg >= len(data) {
+		return 0
+	}
+
+	var raw bytes.Buffer
+
+	for {
+		// safe to assume beg < len(data)
+
+		// check for the end of the code block
+		figEnd, _ := sFigureLine(data[beg:], marker)
+		if figEnd != 0 {
+			beg += figEnd
+			break
+		}
+
+		// copy the current line
+		end := skipUntilChar(data, beg, '\n') + 1
+
+		// did we reach the end of the buffer without a closing marker?
+		if end >= len(data) {
+			return 0
+		}
+
+		// verbatim copy to the working buffer
+		if doRender {
+			raw.Write(data[beg:end])
+		}
+		beg = end
+	}
+
+	if !doRender {
+		return beg
+	}
+
+	figure := &ast.CaptionFigure{}
+	p.addBlock(figure)
+	p.block(raw.Bytes())
+
+	defer p.finalize(figure)
+
+	if captionContent, id, consumed := p.caption(data[beg:], []byte("Figure: ")); consumed > 0 {
+		caption := &ast.Caption{}
+		p.Inline(caption, captionContent)
+
+		figure.HeadingID = id
+
+		p.addChild(caption)
+
+		beg += consumed
+	}
+
+	p.finalize(figure)
+	return beg
+}