Nested postgres transactions in datamapper?

nested-postgres-transactions-in-datamapper

#untested - does this work?

module DataMapper
  class Transaction
    module DataObjectsAdapter
      def nested_transaction_primitive
        DataObjects::SavePoint.create_for_uri(normalized_uri, current_connection)
      end
    end

    # Override to use savepoints for nested transactions
    def connect_adapter(adapter)
      if @transaction_primitives.key?(adapter)
        raise "Already a primitive for adapter #{adapter}"
      end

      primitive = if adapter.current_transaction
        self.state = :none
        adapter.nested_transaction_primitive
      else
        adapter.transaction_primitive
      end

      @transaction_primitives[adapter] = validate_primitive(primitive)
    end
  end
end