1 files changed, 72 insertions, 0 deletions
diff --git a/app/models/concerns/loaded_in_group_list.rb b/app/models/concerns/loaded_in_group_list.rb
new file mode 100644
index 00000000000..dcb3b2b5ff3
--- /dev/null
+++ b/app/models/concerns/loaded_in_group_list.rb
@@ -0,0 +1,72 @@
+module LoadedInGroupList
+  extend ActiveSupport::Concern
+
+  module ClassMethods
+    def with_counts(archived:)
+      selects_including_counts = [
+        'namespaces.*',
+        "(#{project_count_sql(archived).to_sql}) AS preloaded_project_count",
+        "(#{member_count_sql.to_sql}) AS preloaded_member_count",
+        "(#{subgroup_count_sql.to_sql}) AS preloaded_subgroup_count"
+      ]
+
+      select(selects_including_counts)
+    end
+
+    def with_selects_for_list(archived: nil)
+      with_route.with_counts(archived: archived)
+    end
+
+    private
+
+    def project_count_sql(archived = nil)
+      projects = Project.arel_table
+      namespaces = Namespace.arel_table
+
+      base_count = projects.project(Arel.star.count.as('preloaded_project_count'))
+                     .where(projects[:namespace_id].eq(namespaces[:id]))
+      if archived == 'only'
+        base_count.where(projects[:archived].eq(true))
+      elsif Gitlab::Utils.to_boolean(archived)
+        base_count
+      else
+        base_count.where(projects[:archived].not_eq(true))
+      end
+    end
+
+    def subgroup_count_sql
+      namespaces = Namespace.arel_table
+      children = namespaces.alias('children')
+
+      namespaces.project(Arel.star.count.as('preloaded_subgroup_count'))
+        .from(children)
+        .where(children[:parent_id].eq(namespaces[:id]))
+    end
+
+    def member_count_sql
+      members = Member.arel_table
+      namespaces = Namespace.arel_table
+
+      members.project(Arel.star.count.as('preloaded_member_count'))
+        .where(members[:source_type].eq(Namespace.name))
+        .where(members[:source_id].eq(namespaces[:id]))
+        .where(members[:requested_at].eq(nil))
+    end
+  end
+
+  def children_count
+    @children_count ||= project_count + subgroup_count
+  end
+
+  def project_count
+    @project_count ||= try(:preloaded_project_count) || projects.non_archived.count
+  end
+
+  def subgroup_count
+    @subgroup_count ||= try(:preloaded_subgroup_count) || children.count
+  end
+
+  def member_count
+    @member_count ||= try(:preloaded_member_count) || users.count
+  end
+end