3 files changed, 42 insertions, 6 deletions
diff --git a/lib/banzai/filter/inline_diff_filter.rb b/lib/banzai/filter/inline_diff_filter.rb
index 9e75edd4d4c..beb21b19ab3 100644
--- a/lib/banzai/filter/inline_diff_filter.rb
+++ b/lib/banzai/filter/inline_diff_filter.rb
@@ -8,15 +8,19 @@ module Banzai
           next if has_ancestor?(node, IGNORED_ANCESTOR_TAGS)
 
           content = node.to_html
-          content = content.gsub(/(?:\[\-(.*?)\-\]|\{\-(.*?)\-\})/, '<span class="idiff left right deletion">\1\2</span>')
-          content = content.gsub(/(?:\[\+(.*?)\+\]|\{\+(.*?)\+\})/, '<span class="idiff left right addition">\1\2</span>')
+          html_content = inline_diff_filter(content)
 
-          next if html == content
+          next if content == html_content
 
-          node.replace(content)
+          node.replace(html_content)
         end
         doc
       end
+
+      def inline_diff_filter(text)
+        html_content = text.gsub(/(?:\[\-(.*?)\-\]|\{\-(.*?)\-\})/, '<span class="idiff left right deletion">\1\2</span>')
+        html_content.gsub(/(?:\[\+(.*?)\+\]|\{\+(.*?)\+\})/, '<span class="idiff left right addition">\1\2</span>')
+      end
     end
   end
 end
diff --git a/lib/banzai/filter/reference_filter.rb b/lib/banzai/filter/reference_filter.rb
index 41ae0e1f9cc..2d6f34c9cd8 100644
--- a/lib/banzai/filter/reference_filter.rb
+++ b/lib/banzai/filter/reference_filter.rb
@@ -68,6 +68,8 @@ module Banzai
       # by `ignore_ancestor_query`. Link tags are not processed if they have a
       # "gfm" class or the "href" attribute is empty.
       def each_node
+        return to_enum(__method__) unless block_given?
+
         query = %Q{descendant-or-self::text()[not(#{ignore_ancestor_query})]
         | descendant-or-self::a[
           not(contains(concat(" ", @class, " "), " gfm ")) and not(@href = "")
@@ -78,6 +80,11 @@ module Banzai
         end
       end
 
+      # Returns an Array containing all HTML nodes.
+      def nodes
+        @nodes ||= each_node.to_a
+      end
+
       # Yields the link's URL and text whenever the node is a valid <a> tag.
       def yield_valid_link(node)
         link = CGI.unescape(node.attr('href').to_s)
diff --git a/lib/banzai/filter/user_reference_filter.rb b/lib/banzai/filter/user_reference_filter.rb
index 331d8007257..5b0a6d8541b 100644
--- a/lib/banzai/filter/user_reference_filter.rb
+++ b/lib/banzai/filter/user_reference_filter.rb
@@ -29,7 +29,7 @@ module Banzai
         ref_pattern = User.reference_pattern
         ref_pattern_start = /\A#{ref_pattern}\z/
 
-        each_node do |node|
+        nodes.each do |node|
           if text_node?(node)
             replace_text_when_pattern_matches(node, ref_pattern) do |content|
               user_link_filter(content)
@@ -59,7 +59,7 @@ module Banzai
         self.class.references_in(text) do |match, username|
           if username == 'all'
             link_to_all(link_text: link_text)
-          elsif namespace = Namespace.find_by(path: username)
+          elsif namespace = namespaces[username]
             link_to_namespace(namespace, link_text: link_text) || match
           else
             match
@@ -67,6 +67,31 @@ module Banzai
         end
       end
 
+      # Returns a Hash containing all Namespace objects for the username
+      # references in the current document.
+      #
+      # The keys of this Hash are the namespace paths, the values the
+      # corresponding Namespace objects.
+      def namespaces
+        @namespaces ||=
+          Namespace.where(path: usernames).each_with_object({}) do |row, hash|
+            hash[row.path] = row
+          end
+      end
+
+      # Returns all usernames referenced in the current document.
+      def usernames
+        refs = Set.new
+
+        nodes.each do |node|
+          node.to_html.scan(User.reference_pattern) do
+            refs << $~[:user]
+          end
+        end
+
+        refs.to_a
+      end
+
       private
 
       def urls