diff options
Diffstat (limited to 'lib/banzai/filter/markdown_pre_escape_filter.rb')
| -rw-r--r-- | lib/banzai/filter/markdown_pre_escape_filter.rb | 42 |
1 files changed, 38 insertions, 4 deletions
diff --git a/lib/banzai/filter/markdown_pre_escape_filter.rb b/lib/banzai/filter/markdown_pre_escape_filter.rb index 8d54d140877..8cc7b0defd6 100644 --- a/lib/banzai/filter/markdown_pre_escape_filter.rb +++ b/lib/banzai/filter/markdown_pre_escape_filter.rb @@ -10,6 +10,10 @@ module Banzai # This way CommonMark will properly handle the backslash escaped chars # but we will maintain knowledge (the sequence) that it was a literal. # + # This processing is also important for the handling of escaped characters + # in LaTeX math. These will need to be converted back into their escaped + # versions if they are detected in math blocks. + # # We need to surround the character, not just prefix it. It could # get converted into an entity by CommonMark and we wouldn't know how many # characters there are. The entire literal needs to be surrounded with @@ -24,9 +28,36 @@ module Banzai # This filter does the initial surrounding, and MarkdownPostEscapeFilter # does the conversion into span tags. class MarkdownPreEscapeFilter < HTML::Pipeline::TextFilter - # We just need to target those that are special GitLab references - REFERENCE_CHARACTERS = '@#!$&~%^' - ASCII_PUNCTUATION = %r{(\\[#{REFERENCE_CHARACTERS}])}.freeze + # Table of characters that need this special handling. It consists of the + # GitLab special reference characters and special LaTeX characters. + # + # The `token` is used when we do the initial replacement - for example converting + # `\$` into `cmliteral-\+a-cmliteral`. We don't simply replace `\$` with `$`, + # because this can cause difficulties in parsing math blocks that use `$` as a + # delimiter. We also include a character that _can_ be escaped, `\+`. By examining + # the text once it's been passed to markdown, we can determine that `cmliteral-\+a-cmliteral` + # was in a block that markdown did _not_ escape the character, for example an inline + # code block or some other element. In this case, we must convert back to the + # original escaped version, `\$`. However if we detect `cmliteral-+a-cmliteral`, + # then we know markdown considered it an escaped character, and we should replace it + # with the non-escaped version, `$`. + # See the MarkdownPostEscapeFilter for how this is done. + ESCAPABLE_CHARS = [ + { char: '$', escaped: '\$', token: '\+a', reference: true, latex: true }, + { char: '%', escaped: '\%', token: '\+b', reference: true, latex: true }, + { char: '#', escaped: '\#', token: '\+c', reference: true, latex: true }, + { char: '&', escaped: '\&', token: '\+d', reference: true, latex: true }, + { char: '{', escaped: '\{', token: '\+e', reference: false, latex: true }, + { char: '}', escaped: '\}', token: '\+f', reference: false, latex: true }, + { char: '_', escaped: '\_', token: '\+g', reference: false, latex: true }, + { char: '@', escaped: '\@', token: '\+h', reference: true, latex: false }, + { char: '!', escaped: '\!', token: '\+i', reference: true, latex: false }, + { char: '~', escaped: '\~', token: '\+j', reference: true, latex: false }, + { char: '^', escaped: '\^', token: '\+k', reference: true, latex: false } + ].freeze + + TARGET_CHARS = ESCAPABLE_CHARS.pluck(:char).join.freeze + ASCII_PUNCTUATION = %r{(\\[#{TARGET_CHARS}])}.freeze LITERAL_KEYWORD = 'cmliteral' def call @@ -35,7 +66,10 @@ module Banzai # are found, we can bypass the post filter result[:escaped_literals] = true - "#{LITERAL_KEYWORD}-#{match}-#{LITERAL_KEYWORD}" + escaped_item = ESCAPABLE_CHARS.find { |item| item[:escaped] == match } + token = escaped_item ? escaped_item[:token] : match + + "#{LITERAL_KEYWORD}-#{token}-#{LITERAL_KEYWORD}" end end end |