1 files changed, 40 insertions, 0 deletions
diff --git a/lib/banzai/filter/markdown_post_escape_filter.rb b/lib/banzai/filter/markdown_post_escape_filter.rb
new file mode 100644
index 00000000000..ad32e9afbf5
--- /dev/null
+++ b/lib/banzai/filter/markdown_post_escape_filter.rb
@@ -0,0 +1,40 @@
+# frozen_string_literal: true
+
+module Banzai
+  module Filter
+    class MarkdownPostEscapeFilter < HTML::Pipeline::Filter
+      LITERAL_KEYWORD   = MarkdownPreEscapeFilter::LITERAL_KEYWORD
+      LITERAL_REGEX     = %r{#{LITERAL_KEYWORD}-(.*?)-#{LITERAL_KEYWORD}}.freeze
+      NOT_LITERAL_REGEX = %r{#{LITERAL_KEYWORD}-((%5C|\\).+?)-#{LITERAL_KEYWORD}}.freeze
+      SPAN_REGEX        = %r{<span>(.*?)</span>}.freeze
+
+      def call
+        return doc unless result[:escaped_literals]
+
+        # For any literals that actually didn't get escape processed
+        # (for example in code blocks), remove the special sequence.
+        html.gsub!(NOT_LITERAL_REGEX, '\1')
+
+        # Replace any left over literal sequences with `span` so that our
+        # reference processing is short-circuited
+        html.gsub!(LITERAL_REGEX, '<span>\1</span>')
+
+        # Since literals are converted in links, we need to remove any surrounding `span`.
+        # Note: this could have been done in the renderer,
+        # Banzai::Renderer::CommonMark::HTML.  However, we eventually want to use
+        # the built-in compiled renderer, rather than the ruby version, for speed.
+        # So let's do this work here.
+        doc.css('a').each do |node|
+          node.attributes['href'].value  = node.attributes['href'].value.gsub(SPAN_REGEX, '\1') if node.attributes['href']
+          node.attributes['title'].value = node.attributes['title'].value.gsub(SPAN_REGEX, '\1') if node.attributes['title']
+        end
+
+        doc.css('code').each do |node|
+          node.attributes['lang'].value  = node.attributes['lang'].value.gsub(SPAN_REGEX, '\1') if node.attributes['lang']
+        end
+
+        doc
+      end
+    end
+  end
+end