Move Markdown/reference logic from Gitlab::Markdown to Banzai

1 files changed, 69 insertions, 0 deletions

diff --git a/lib/banzai/filter/external_issue_reference_filter.rb b/lib/banzai/filter/external_issue_reference_filter.rb
new file mode 100644
index 00000000000..f5737a7ac19
--- /dev/null
+++ b/lib/banzai/filter/external_issue_reference_filter.rb
@@ -0,0 +1,69 @@
+require 'banzai'
+
+module Banzai
+  module Filter
+    # HTML filter that replaces external issue tracker references with links.
+    # References are ignored if the project doesn't use an external issue
+    # tracker.
+    class ExternalIssueReferenceFilter < ReferenceFilter
+      # Public: Find `JIRA-123` issue references in text
+      #
+      #   ExternalIssueReferenceFilter.references_in(text) do |match, issue|
+      #     "<a href=...>##{issue}</a>"
+      #   end
+      #
+      # text - String text to search.
+      #
+      # Yields the String match and the String issue reference.
+      #
+      # Returns a String replaced with the return of the block.
+      def self.references_in(text)
+        text.gsub(ExternalIssue.reference_pattern) do |match|
+          yield match, $~[:issue]
+        end
+      end
+
+      def call
+        # Early return if the project isn't using an external tracker
+        return doc if project.nil? || project.default_issues_tracker?
+
+        replace_text_nodes_matching(ExternalIssue.reference_pattern) do |content|
+          issue_link_filter(content)
+        end
+
+        replace_link_nodes_with_href(ExternalIssue.reference_pattern) do |link, text|
+          issue_link_filter(link, link_text: text)
+        end
+      end
+
+      # Replace `JIRA-123` issue references in text with links to the referenced
+      # issue's details page.
+      #
+      # text - String text to replace references in.
+      #
+      # Returns a String with `JIRA-123` references replaced with links. All
+      # links have `gfm` and `gfm-issue` class names attached for styling.
+      def issue_link_filter(text, link_text: nil)
+        project = context[:project]
+
+        self.class.references_in(text) do |match, issue|
+          url = url_for_issue(issue, project, only_path: context[:only_path])
+
+          title = escape_once("Issue in #{project.external_issue_tracker.title}")
+          klass = reference_class(:issue)
+          data  = data_attribute(project: project.id)
+
+          text = link_text || match
+
+          %(<a href="#{url}" #{data}
+               title="#{title}"
+               class="#{klass}">#{text}</a>)
+        end
+      end
+
+      def url_for_issue(*args)
+        IssuesHelper.url_for_issue(*args)
+      end
+    end
+  end
+end