81 lines
2.8 KiB
Ruby
81 lines
2.8 KiB
Ruby
# frozen_string_literal: true
|
|
|
|
# Generated HTML is transformed back to GFM by:
|
|
# - app/assets/javascripts/behaviors/markdown/marks/math.js
|
|
# - app/assets/javascripts/behaviors/markdown/nodes/code_block.js
|
|
module Banzai
|
|
module Filter
|
|
# HTML filter that implements our dollar math syntax, one of three filters:
|
|
# DollarMathPreFilter, DollarMathPostFilter, and MathFilter
|
|
#
|
|
class DollarMathPostFilter < HTML::Pipeline::Filter
|
|
# Based on the Pandoc heuristics,
|
|
# https://pandoc.org/MANUAL.html#extension-tex_math_dollars
|
|
#
|
|
# Handle the $...$ and $$...$$ inline syntax in this filter, after markdown processing
|
|
# but before post-handling of escaped characters. Any escaped $ will have been specially
|
|
# encoded and will therefore not interfere with the detection of the dollar syntax.
|
|
|
|
# Corresponds to the "$...$" syntax
|
|
DOLLAR_INLINE_UNTRUSTED =
|
|
'(?P<matched>\$(?P<math>(?:\S[^$\n]*?\S|[^$\s]))\$)(?:[^\d]|$)'
|
|
DOLLAR_INLINE_UNTRUSTED_REGEX =
|
|
Gitlab::UntrustedRegexp.new(DOLLAR_INLINE_UNTRUSTED, multiline: false)
|
|
|
|
# Corresponds to the "$$...$$" syntax
|
|
DOLLAR_DISPLAY_INLINE_UNTRUSTED =
|
|
'(?P<matched>\$\$\ *(?P<math>[^$\n]+?)\ *\$\$)'
|
|
DOLLAR_DISPLAY_INLINE_UNTRUSTED_REGEX =
|
|
Gitlab::UntrustedRegexp.new(DOLLAR_DISPLAY_INLINE_UNTRUSTED, multiline: false)
|
|
|
|
# Order dependent. Handle the `$$` syntax before the `$` syntax
|
|
DOLLAR_MATH_PIPELINE = [
|
|
{ pattern: DOLLAR_DISPLAY_INLINE_UNTRUSTED_REGEX, style: :display },
|
|
{ pattern: DOLLAR_INLINE_UNTRUSTED_REGEX, style: :inline }
|
|
].freeze
|
|
|
|
# Do not recognize math inside these tags
|
|
IGNORED_ANCESTOR_TAGS = %w[pre code tt].to_set
|
|
|
|
def call
|
|
process_dollar_pipeline
|
|
|
|
doc
|
|
end
|
|
|
|
def process_dollar_pipeline
|
|
doc.xpath('descendant-or-self::text()').each do |node|
|
|
next if has_ancestor?(node, IGNORED_ANCESTOR_TAGS)
|
|
|
|
node_html = node.to_html
|
|
next unless DOLLAR_INLINE_UNTRUSTED_REGEX.match?(node_html) ||
|
|
DOLLAR_DISPLAY_INLINE_UNTRUSTED_REGEX.match?(node_html)
|
|
|
|
temp_doc = Nokogiri::HTML.fragment(node_html)
|
|
|
|
DOLLAR_MATH_PIPELINE.each do |pipeline|
|
|
temp_doc.xpath('child::text()').each do |temp_node|
|
|
html = temp_node.to_html
|
|
|
|
pipeline[:pattern].scan(temp_node.content).each do |match|
|
|
math = pipeline[:pattern].extract_named_group(:math, match)
|
|
html.sub!(match.first, math_html(math: math, style: pipeline[:style]))
|
|
end
|
|
|
|
temp_node.replace(html)
|
|
end
|
|
end
|
|
|
|
node.replace(temp_doc)
|
|
end
|
|
end
|
|
|
|
private
|
|
|
|
def math_html(math:, style:)
|
|
"<code data-math-style=\"#{style}\">#{math}</code>"
|
|
end
|
|
end
|
|
end
|
|
end
|