Rewrite markdown rendering to blackfriday v2 and rewrite orgmode rendering to go-org (#8560)

* Rewrite markdown rendering to blackfriday v2.0

* Fix style

* Fix go mod with golang 1.13

* Fix blackfriday v2 import

* Inital orgmode renderer migration to go-org

* Vendor go-org dependency

* Ignore errors :/

* Update go-org to latest version

* Update test

* Fix go-org test

* Remove unneeded code

* Fix comments

* Fix markdown test

* Fix blackfriday regression rendering HTML block

vendor/github.com/niklasfasching/go-org/org/drawer.go

@@ -0,0 +1,97 @@
+package org
+
+import (
+	"regexp"
+	"strings"
+)
+
+type Drawer struct {
+	Name     string
+	Children []Node
+}
+
+type PropertyDrawer struct {
+	Properties [][]string
+}
+
+var beginDrawerRegexp = regexp.MustCompile(`^(\s*):(\S+):\s*$`)
+var endDrawerRegexp = regexp.MustCompile(`^(\s*):END:\s*$`)
+var propertyRegexp = regexp.MustCompile(`^(\s*):(\S+):(\s+(.*)$|$)`)
+
+func lexDrawer(line string) (token, bool) {
+	if m := endDrawerRegexp.FindStringSubmatch(line); m != nil {
+		return token{"endDrawer", len(m[1]), "", m}, true
+	} else if m := beginDrawerRegexp.FindStringSubmatch(line); m != nil {
+		return token{"beginDrawer", len(m[1]), strings.ToUpper(m[2]), m}, true
+	}
+	return nilToken, false
+}
+
+func (d *Document) parseDrawer(i int, parentStop stopFn) (int, Node) {
+	name := strings.ToUpper(d.tokens[i].content)
+	if name == "PROPERTIES" {
+		return d.parsePropertyDrawer(i, parentStop)
+	}
+	drawer, start := Drawer{Name: name}, i
+	i++
+	stop := func(d *Document, i int) bool {
+		if parentStop(d, i) {
+			return true
+		}
+		kind := d.tokens[i].kind
+		return kind == "beginDrawer" || kind == "endDrawer" || kind == "headline"
+	}
+	for {
+		consumed, nodes := d.parseMany(i, stop)
+		i += consumed
+		drawer.Children = append(drawer.Children, nodes...)
+		if i < len(d.tokens) && d.tokens[i].kind == "beginDrawer" {
+			p := Paragraph{[]Node{Text{":" + d.tokens[i].content + ":", false}}}
+			drawer.Children = append(drawer.Children, p)
+			i++
+		} else {
+			break
+		}
+	}
+	if i < len(d.tokens) && d.tokens[i].kind == "endDrawer" {
+		i++
+	}
+	return i - start, drawer
+}
+
+func (d *Document) parsePropertyDrawer(i int, parentStop stopFn) (int, Node) {
+	drawer, start := PropertyDrawer{}, i
+	i++
+	stop := func(d *Document, i int) bool {
+		return parentStop(d, i) || (d.tokens[i].kind != "text" && d.tokens[i].kind != "beginDrawer")
+	}
+	for ; !stop(d, i); i++ {
+		m := propertyRegexp.FindStringSubmatch(d.tokens[i].matches[0])
+		if m == nil {
+			return 0, nil
+		}
+		k, v := strings.ToUpper(m[2]), strings.TrimSpace(m[4])
+		drawer.Properties = append(drawer.Properties, []string{k, v})
+	}
+	if i < len(d.tokens) && d.tokens[i].kind == "endDrawer" {
+		i++
+	} else {
+		return 0, nil
+	}
+	return i - start, drawer
+}
+
+func (d *PropertyDrawer) Get(key string) (string, bool) {
+	if d == nil {
+		return "", false
+	}
+	for _, kvPair := range d.Properties {
+		if kvPair[0] == key {
+			return kvPair[1], true
+		}
+	}
+	return "", false
+}
+
+func (n Drawer) String() string         { return orgWriter.nodesAsString(n) }
+func (n PropertyDrawer) String() string { return orgWriter.nodesAsString(n) }