# 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:only-child' 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=\"#{escape_once(sourcepos)}\"" : '' highlighted = %(
#{code}
'.
# "```ruby:with:options```" -> ''.
#
# New ones:
# "```ruby with options```" -> ''.
# "```ruby:with:options```" -> ''.
language = node.attr('lang')
return unless language
language, language_params = language.split(LANG_PARAMS_DELIMITER, 2)
language_params = [node.attr('data-meta'), language_params].compact.join(' ')
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
# Replace the parent `pre` element with the entire highlighted block
def replace_parent_pre_element(node, highlighted)
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