1 files changed, 61 insertions, 0 deletions
diff --git a/app/models/namespaces/traversal/recursive.rb b/app/models/namespaces/traversal/recursive.rb
new file mode 100644
index 00000000000..c46cc521735
--- /dev/null
+++ b/app/models/namespaces/traversal/recursive.rb
@@ -0,0 +1,61 @@
+# frozen_string_literal: true
+
+module Namespaces
+  module Traversal
+    module Recursive
+      extend ActiveSupport::Concern
+
+      def root_ancestor
+        return self if persisted? && parent_id.nil?
+
+        strong_memoize(:root_ancestor) do
+          self_and_ancestors.reorder(nil).find_by(parent_id: nil)
+        end
+      end
+
+      # Returns all ancestors, self, and descendants of the current namespace.
+      def self_and_hierarchy
+        Gitlab::ObjectHierarchy
+          .new(self.class.where(id: id))
+          .all_objects
+      end
+
+      # Returns all the ancestors of the current namespaces.
+      def ancestors
+        return self.class.none unless parent_id
+
+        Gitlab::ObjectHierarchy
+          .new(self.class.where(id: parent_id))
+          .base_and_ancestors
+      end
+
+      # returns all ancestors upto but excluding the given namespace
+      # when no namespace is given, all ancestors upto the top are returned
+      def ancestors_upto(top = nil, hierarchy_order: nil)
+        Gitlab::ObjectHierarchy.new(self.class.where(id: id))
+          .ancestors(upto: top, hierarchy_order: hierarchy_order)
+      end
+
+      def self_and_ancestors(hierarchy_order: nil)
+        return self.class.where(id: id) unless parent_id
+
+        Gitlab::ObjectHierarchy
+          .new(self.class.where(id: id))
+          .base_and_ancestors(hierarchy_order: hierarchy_order)
+      end
+
+      # Returns all the descendants of the current namespace.
+      def descendants
+        Gitlab::ObjectHierarchy
+          .new(self.class.where(parent_id: id))
+          .base_and_descendants
+      end
+
+      def self_and_descendants
+        Gitlab::ObjectHierarchy
+          .new(self.class.where(id: id))
+          .base_and_descendants
+      end
+    end
+  end
+end