michael@0: /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #include "nsISupports.idl"
michael@0: 
michael@0: interface mozIStorageConnection;
michael@0: interface mozIStorageValueArray;
michael@0: interface nsIArray;
michael@0: interface nsIVariant;
michael@0: 
michael@0: /**
michael@0:  * mozIStorageAggregateFunction represents aggregate SQL function.
michael@0:  * Common examples of aggregate functions are SUM() and COUNT().
michael@0:  *
michael@0:  * An aggregate function calculates one result for a given set of data, where
michael@0:  * a set of data is a group of tuples. There can be one group
michael@0:  * per request or many of them, if GROUP BY clause is used or not.
michael@0:  */
michael@0: [scriptable, uuid(763217b7-3123-11da-918d-000347412e16)]
michael@0: interface mozIStorageAggregateFunction : nsISupports {
michael@0:   /**
michael@0:    * onStep is called when next value should be passed to
michael@0:    * a custom function.
michael@0:    * 
michael@0:    * @param aFunctionArguments    The arguments passed in to the function
michael@0:    */
michael@0:   void onStep(in mozIStorageValueArray aFunctionArguments);
michael@0: 
michael@0:   /**
michael@0:    * Called when all tuples in a group have been processed and the engine
michael@0:    * needs the aggregate function's value.
michael@0:    *
michael@0:    * @returns aggregate result as Variant.
michael@0:    */
michael@0:   nsIVariant onFinal();
michael@0: };