Add support for markdown to HTML conversion (matrix). Closes #663 (#670)

This uses our own gomatrix lib with the SendHTML function which
adds HTML to formatted_body in matrix.
golang-commonmark is used to convert markdown into valid HTML.

1 files changed, 222 insertions, 0 deletions

diff --git a/vendor/gitlab.com/golang-commonmark/markdown/html_block.go b/vendor/gitlab.com/golang-commonmark/markdown/html_block.go
new file mode 100644
index 00000000..98a89499
--- /dev/null
+++ b/vendor/gitlab.com/golang-commonmark/markdown/html_block.go
@@ -0,0 +1,222 @@
+// Copyright 2015 The Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package markdown
+
+import (
+	"regexp"
+	"strings"
+)
+
+var (
+	htmlBlocks = []string{
+		"address",
+		"article",
+		"aside",
+		"base",
+		"basefont",
+		"blockquote",
+		"body",
+		"caption",
+		"center",
+		"col",
+		"colgroup",
+		"dd",
+		"details",
+		"dialog",
+		"dir",
+		"div",
+		"dl",
+		"dt",
+		"fieldset",
+		"figcaption",
+		"figure",
+		"footer",
+		"form",
+		"frame",
+		"frameset",
+		"h1",
+		"h2",
+		"h3",
+		"h4",
+		"h5",
+		"h6",
+		"head",
+		"header",
+		"hr",
+		"html",
+		"iframe",
+		"legend",
+		"li",
+		"link",
+		"main",
+		"menu",
+		"menuitem",
+		"meta",
+		"nav",
+		"noframes",
+		"ol",
+		"optgroup",
+		"option",
+		"p",
+		"param",
+		"section",
+		"source",
+		"summary",
+		"table",
+		"tbody",
+		"td",
+		"tfoot",
+		"th",
+		"thead",
+		"title",
+		"tr",
+		"track",
+		"ul",
+	}
+
+	htmlBlocksSet = make(map[string]bool)
+
+	rStartCond1 = regexp.MustCompile(`(?i)^(pre|script|style)([\n\t >]|$)`)
+	rEndCond1   = regexp.MustCompile(`(?i)</(pre|script|style)>`)
+	rStartCond6 = regexp.MustCompile(`(?i)^/?(` + strings.Join(htmlBlocks, "|") + `)(\s|$|>|/>)`)
+	rStartCond7 = regexp.MustCompile(`(?i)^(/[a-z][a-z0-9-]*|[a-z][a-z0-9-]*(\s+[a-z_:][a-z0-9_.:-]*\s*=\s*("[^"]*"|'[^']*'|[ "'=<>\x60]))*\s*/?)>\s*$`)
+)
+
+func init() {
+	for _, tag := range htmlBlocks {
+		htmlBlocksSet[tag] = true
+	}
+}
+
+func min(a, b int) int {
+	if a < b {
+		return a
+	}
+	return b
+}
+
+func matchTagName(s string) string {
+	if len(s) < 2 {
+		return ""
+	}
+
+	i := 0
+	if s[0] == '/' {
+		i++
+	}
+	start := i
+	max := min(15+i, len(s))
+	for i < max && isLetter(s[i]) {
+		i++
+	}
+	if i >= len(s) {
+		return ""
+	}
+
+	switch s[i] {
+	case ' ', '\n', '/', '>':
+		return strings.ToLower(s[start:i])
+	default:
+		return ""
+	}
+}
+
+func ruleHTMLBlock(s *StateBlock, startLine, endLine int, silent bool) bool {
+	if !s.Md.HTML {
+		return false
+	}
+
+	pos := s.BMarks[startLine] + s.TShift[startLine]
+	max := s.EMarks[startLine]
+
+	if pos+1 >= max {
+		return false
+	}
+
+	src := s.Src
+
+	if src[pos] != '<' {
+		return false
+	}
+
+	pos++
+	b := src[pos]
+	if !htmlSecond(b) {
+		return false
+	}
+
+	nextLine := startLine + 1
+
+	var endCond func(string) bool
+
+	if pos+2 < max && isLetter(b) && rStartCond1.MatchString(src[pos:]) {
+		endCond = func(s string) bool {
+			return rEndCond1.MatchString(s)
+		}
+	} else if strings.HasPrefix(src[pos:], "!--") {
+		endCond = func(s string) bool {
+			return strings.Contains(s, "-->")
+		}
+	} else if b == '?' {
+		endCond = func(s string) bool {
+			return strings.Contains(s, "?>")
+		}
+	} else if b == '!' && pos+1 < max && isUppercaseLetter(src[pos+1]) {
+		endCond = func(s string) bool {
+			return strings.Contains(s, ">")
+		}
+	} else if strings.HasPrefix(src[pos:], "![CDATA[") {
+		endCond = func(s string) bool {
+			return strings.Contains(s, "]]>")
+		}
+	} else if pos+2 < max && (isLetter(b) || b == '/' && isLetter(src[pos+1])) {
+		terminator := true
+		if rStartCond6.MatchString(src[pos:max]) {
+		} else if rStartCond7.MatchString(src[pos:max]) {
+			terminator = false
+		} else {
+			return false
+		}
+		if silent {
+			return terminator
+		}
+		endCond = func(s string) bool {
+			return s == ""
+		}
+	} else {
+		return false
+	}
+
+	if silent {
+		return true
+	}
+
+	if !endCond(src[pos:max]) {
+		for nextLine < endLine {
+			if s.SCount[nextLine] < s.BlkIndent {
+				break
+			}
+
+			pos := s.BMarks[nextLine] + s.TShift[nextLine]
+			max := s.EMarks[nextLine]
+			lineText := src[pos:max]
+			if endCond(lineText) {
+				if pos != max {
+					nextLine++
+				}
+				break
+			}
+			nextLine++
+		}
+	}
+
+	s.Line = nextLine
+	s.PushToken(&HTMLBlock{
+		Content: s.Lines(startLine, nextLine, s.BlkIndent, true),
+		Map:     [2]int{startLine, nextLine},
+	})
+
+	return true
+}