88c2e24360
This PR adds mathematical rendering with KaTeX. The first step is to add a Goldmark extension that detects the latex (and tex) mathematics delimiters. The second step to make this extension only run if math support is enabled. The second step is to then add KaTeX CSS and JS to the head which will load after the dom is rendered. Fix #3445 Signed-off-by: Andrew Thornton <art27@cantab.net> Signed-off-by: Andrew Thornton <art27@cantab.net> Co-authored-by: silverwind <me@silverwind.io> Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
106 lines
2.3 KiB
Go
106 lines
2.3 KiB
Go
// Copyright 2020 The Gitea Authors. All rights reserved.
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// Use of this source code is governed by a MIT-style
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// license that can be found in the LICENSE file.
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package markdown
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import (
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"bytes"
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"errors"
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"unicode"
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"unicode/utf8"
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"code.gitea.io/gitea/modules/log"
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"gopkg.in/yaml.v3"
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)
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func isYAMLSeparator(line []byte) bool {
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idx := 0
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for ; idx < len(line); idx++ {
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if line[idx] >= utf8.RuneSelf {
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r, sz := utf8.DecodeRune(line[idx:])
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if !unicode.IsSpace(r) {
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return false
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}
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idx += sz
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continue
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}
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if line[idx] != ' ' {
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break
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}
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}
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dashCount := 0
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for ; idx < len(line); idx++ {
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if line[idx] != '-' {
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break
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}
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dashCount++
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}
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if dashCount < 3 {
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return false
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}
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for ; idx < len(line); idx++ {
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if line[idx] >= utf8.RuneSelf {
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r, sz := utf8.DecodeRune(line[idx:])
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if !unicode.IsSpace(r) {
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return false
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}
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idx += sz
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continue
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}
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if line[idx] != ' ' {
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return false
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}
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}
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return true
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}
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// ExtractMetadata consumes a markdown file, parses YAML frontmatter,
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// and returns the frontmatter metadata separated from the markdown content
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func ExtractMetadata(contents string, out interface{}) (string, error) {
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body, err := ExtractMetadataBytes([]byte(contents), out)
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return string(body), err
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}
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// ExtractMetadata consumes a markdown file, parses YAML frontmatter,
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// and returns the frontmatter metadata separated from the markdown content
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func ExtractMetadataBytes(contents []byte, out interface{}) ([]byte, error) {
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var front, body []byte
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start, end := 0, len(contents)
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idx := bytes.IndexByte(contents[start:], '\n')
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if idx >= 0 {
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end = start + idx
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}
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line := contents[start:end]
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if !isYAMLSeparator(line) {
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return contents, errors.New("frontmatter must start with a separator line")
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}
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frontMatterStart := end + 1
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for start = frontMatterStart; start < len(contents); start = end + 1 {
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end = len(contents)
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idx := bytes.IndexByte(contents[start:], '\n')
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if idx >= 0 {
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end = start + idx
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}
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line := contents[start:end]
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if isYAMLSeparator(line) {
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front = contents[frontMatterStart:start]
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body = contents[end+1:]
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break
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}
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}
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if len(front) == 0 {
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return contents, errors.New("could not determine metadata")
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}
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log.Info("%s", string(front))
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if err := yaml.Unmarshal(front, out); err != nil {
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return contents, err
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}
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return body, nil
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}
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