github.com/kovansky/hugo@v0.92.3-0.20220224232819-63076e4ff19f/markup/blackfriday/renderer.go (about)

     1  // Copyright 2019 The Hugo Authors. All rights reserved.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  // http://www.apache.org/licenses/LICENSE-2.0
     7  //
     8  // Unless required by applicable law or agreed to in writing, software
     9  // distributed under the License is distributed on an "AS IS" BASIS,
    10  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    11  // See the License for the specific language governing permissions and
    12  // limitations under the License.
    13  
    14  package blackfriday
    15  
    16  import (
    17  	"bytes"
    18  	"strings"
    19  
    20  	"github.com/russross/blackfriday"
    21  )
    22  
    23  // hugoHTMLRenderer wraps a blackfriday.Renderer, typically a blackfriday.Html
    24  // adding some custom behaviour.
    25  type hugoHTMLRenderer struct {
    26  	c *blackfridayConverter
    27  	blackfriday.Renderer
    28  }
    29  
    30  // BlockCode renders a given text as a block of code.
    31  // Chroma is used if it is setup to handle code fences.
    32  func (r *hugoHTMLRenderer) BlockCode(out *bytes.Buffer, text []byte, lang string) {
    33  	if r.c.cfg.MarkupConfig.Highlight.CodeFences {
    34  		str := strings.Trim(string(text), "\n\r")
    35  		highlighted, _ := r.c.cfg.Highlight(str, lang, "")
    36  		out.WriteString(highlighted)
    37  	} else {
    38  		r.Renderer.BlockCode(out, text, lang)
    39  	}
    40  }
    41  
    42  // ListItem adds task list support to the Blackfriday renderer.
    43  func (r *hugoHTMLRenderer) ListItem(out *bytes.Buffer, text []byte, flags int) {
    44  	if !r.c.bf.TaskLists {
    45  		r.Renderer.ListItem(out, text, flags)
    46  		return
    47  	}
    48  
    49  	switch {
    50  	case bytes.HasPrefix(text, []byte("[ ] ")):
    51  		text = append([]byte(`<label><input type="checkbox" disabled class="task-list-item">`), text[3:]...)
    52  		text = append(text, []byte(`</label>`)...)
    53  
    54  	case bytes.HasPrefix(text, []byte("[x] ")) || bytes.HasPrefix(text, []byte("[X] ")):
    55  		text = append([]byte(`<label><input type="checkbox" checked disabled class="task-list-item">`), text[3:]...)
    56  		text = append(text, []byte(`</label>`)...)
    57  	}
    58  
    59  	r.Renderer.ListItem(out, text, flags)
    60  }
    61  
    62  // List adds task list support to the Blackfriday renderer.
    63  func (r *hugoHTMLRenderer) List(out *bytes.Buffer, text func() bool, flags int) {
    64  	if !r.c.bf.TaskLists {
    65  		r.Renderer.List(out, text, flags)
    66  		return
    67  	}
    68  	marker := out.Len()
    69  	r.Renderer.List(out, text, flags)
    70  	if out.Len() > marker {
    71  		list := out.Bytes()[marker:]
    72  		if bytes.Contains(list, []byte("task-list-item")) {
    73  			// Find the index of the first >, it might be 3 or 4 depending on whether
    74  			// there is a new line at the start, but this is safer than just hardcoding it.
    75  			closingBracketIndex := bytes.Index(list, []byte(">"))
    76  			// Rewrite the buffer from the marker
    77  			out.Truncate(marker)
    78  			// Safely assuming closingBracketIndex won't be -1 since there is a list
    79  			// May be either dl, ul or ol
    80  			list := append(list[:closingBracketIndex], append([]byte(` class="task-list"`), list[closingBracketIndex:]...)...)
    81  			out.Write(list)
    82  		}
    83  	}
    84  }