1 files changed, 85 insertions, 0 deletions
diff --git a/markup/blackfriday/renderer.go b/markup/blackfriday/renderer.go
new file mode 100644
index 000000000..9f4d44e02
--- /dev/null
+++ b/markup/blackfriday/renderer.go
@@ -0,0 +1,85 @@
+// Copyright 2019 The Hugo Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package blackfriday
+
+import (
+	"bytes"
+	"strings"
+
+	"github.com/russross/blackfriday"
+)
+
+// hugoHTMLRenderer wraps a blackfriday.Renderer, typically a blackfriday.Html
+// adding some custom behaviour.
+type hugoHTMLRenderer struct {
+	c *blackfridayConverter
+	blackfriday.Renderer
+}
+
+// BlockCode renders a given text as a block of code.
+// Pygments is used if it is setup to handle code fences.
+func (r *hugoHTMLRenderer) BlockCode(out *bytes.Buffer, text []byte, lang string) {
+	if r.c.pygmentsCodeFences && (lang != "" || r.c.pygmentsCodeFencesGuessSyntax) {
+		opts := r.c.pygmentsOptions
+		str := strings.Trim(string(text), "\n\r")
+		highlighted, _ := r.c.cfg.Highlight(str, lang, opts)
+		out.WriteString(highlighted)
+	} else {
+		r.Renderer.BlockCode(out, text, lang)
+	}
+}
+
+// ListItem adds task list support to the Blackfriday renderer.
+func (r *hugoHTMLRenderer) ListItem(out *bytes.Buffer, text []byte, flags int) {
+	if !r.c.bf.TaskLists {
+		r.Renderer.ListItem(out, text, flags)
+		return
+	}
+
+	switch {
+	case bytes.HasPrefix(text, []byte("[ ] ")):
+		text = append([]byte(`<label><input type="checkbox" disabled class="task-list-item">`), text[3:]...)
+		text = append(text, []byte(`</label>`)...)
+
+	case bytes.HasPrefix(text, []byte("[x] ")) || bytes.HasPrefix(text, []byte("[X] ")):
+		text = append([]byte(`<label><input type="checkbox" checked disabled class="task-list-item">`), text[3:]...)
+		text = append(text, []byte(`</label>`)...)
+	}
+
+	r.Renderer.ListItem(out, text, flags)
+}
+
+// List adds task list support to the Blackfriday renderer.
+func (r *hugoHTMLRenderer) List(out *bytes.Buffer, text func() bool, flags int) {
+	if !r.c.bf.TaskLists {
+		r.Renderer.List(out, text, flags)
+		return
+	}
+	marker := out.Len()
+	r.Renderer.List(out, text, flags)
+	if out.Len() > marker {
+		list := out.Bytes()[marker:]
+		if bytes.Contains(list, []byte("task-list-item")) {
+			// Find the index of the first >, it might be 3 or 4 depending on whether
+			// there is a new line at the start, but this is safer than just hardcoding it.
+			closingBracketIndex := bytes.Index(list, []byte(">"))
+			// Rewrite the buffer from the marker
+			out.Truncate(marker)
+			// Safely assuming closingBracketIndex won't be -1 since there is a list
+			// May be either dl, ul or ol
+			list := append(list[:closingBracketIndex], append([]byte(` class="task-list"`), list[closingBracketIndex:]...)...)
+			out.Write(list)
+		}
+	}
+}