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|
# frozen_string_literal: true
require 'rouge/plugins/common_mark'
require "asciidoctor/extensions/asciidoctor_kroki/extension"
# Generated HTML is transformed back to GFM by app/assets/javascripts/behaviors/markdown/nodes/code_block.js
module Banzai
module Filter
# HTML Filter to highlight fenced code blocks
#
class SyntaxHighlightFilter < HTML::Pipeline::Filter
include OutputSafety
LANG_PARAMS_DELIMITER = ':'
LANG_PARAMS_ATTR = 'data-lang-params'
CSS = 'pre:not([data-math-style]):not([data-mermaid-style]):not([data-kroki-style]) > code'
XPATH = Gitlab::Utils::Nokogiri.css_to_xpath(CSS).freeze
def call
doc.xpath(XPATH).each do |node|
highlight_node(node)
end
doc
end
def highlight_node(node)
css_classes = +'code highlight js-syntax-highlight'
lang, lang_params = parse_lang_params(node)
sourcepos = node.parent.attr('data-sourcepos')
retried = false
if use_rouge?(lang)
lexer = lexer_for(lang)
language = lexer.tag
else
lexer = Rouge::Lexers::PlainText.new
language = lang
end
begin
code = Rouge::Formatters::HTMLGitlab.format(lex(lexer, node.text), tag: language)
css_classes << " language-#{language}" if language
rescue StandardError
# Gracefully handle syntax highlighter bugs/errors to ensure users can
# still access an issue/comment/etc. First, retry with the plain text
# filter. If that fails, then just skip this entirely, but that would
# be a pretty bad upstream bug.
return if retried
language = nil
lexer = Rouge::Lexers::PlainText.new
retried = true
retry
end
sourcepos_attr = sourcepos ? "data-sourcepos=\"#{sourcepos}\"" : ''
highlighted = %(<div class="gl-relative markdown-code-block js-markdown-code"><pre #{sourcepos_attr} class="#{css_classes}"
lang="#{language}"
#{lang_params}
v-pre="true"><code>#{code}</code></pre><copy-code></copy-code></div>)
# Extracted to a method to measure it
replace_parent_pre_element(node, highlighted)
end
private
def parse_lang_params(node)
node = node.parent if Feature.enabled?(:use_cmark_renderer, default_enabled: :yaml)
# Commonmarker's FULL_INFO_STRING render option works with the space delimiter.
# But the current behavior of GitLab's markdown renderer is different - it grabs everything as the single
# line, including language and its options. To keep backward compatability, we have to parse the old format and
# merge with the new one.
#
# Behaviors before separating language and its parameters:
# Old ones:
# "```ruby with options```" -> '<pre><code lang="ruby with options">'.
# "```ruby:with:options```" -> '<pre><code lang="ruby:with:options">'.
#
# New ones:
# "```ruby with options```" -> '<pre><code lang="ruby" data-meta="with options">'.
# "```ruby:with:options```" -> '<pre><code lang="ruby:with:options">'.
language = node.attr('lang')
return unless language
language, language_params = language.split(LANG_PARAMS_DELIMITER, 2)
if Feature.enabled?(:use_cmark_renderer, default_enabled: :yaml)
language_params = [node.attr('data-meta'), language_params].compact.join(' ')
end
formatted_language_params = format_language_params(language_params)
[language, formatted_language_params]
end
# Separate method so it can be instrumented.
def lex(lexer, code)
lexer.lex(code)
end
def lexer_for(language)
(Rouge::Lexer.find(language) || Rouge::Lexers::PlainText).new
end
def replace_parent_pre_element(node, highlighted)
# Replace the parent `pre` element with the entire highlighted block
node.parent.replace(highlighted)
end
def use_rouge?(language)
(%w(math suggestion) + ::AsciidoctorExtensions::Kroki::SUPPORTED_DIAGRAM_NAMES).exclude?(language)
end
def format_language_params(language_params)
return if language_params.blank?
%(#{LANG_PARAMS_ATTR}="#{escape_once(language_params)}")
end
end
end
end
|
