gecko-dev/storage/public/mozIStorageAggregateFunctio...

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is Storage Code.
*
* The Initial Developer of the Original Code is
* Lev Serebryakov <lev@serebryakov.spb.ru>
* Portions created by the Initial Developer are Copyright (C) 2007
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU General Public License Version 2 or later (the "GPL"), or
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
#include "nsISupports.idl"
interface mozIStorageConnection;
interface mozIStorageValueArray;
interface nsIArray;
interface nsIVariant;
/**
* mozIStorageAggregateFunction represents aggregate SQL function.
* Common examples of aggregate functions are SUM() and COUNT().
*
* An aggregate function calculates one result for a given set of data, where
* a set of data is a group of tuples. There can be one group
* per request or many of them, if GROUP BY clause is used or not.
*/
[scriptable, uuid(763217b7-3123-11da-918d-000347412e16)]
interface mozIStorageAggregateFunction : nsISupports {
/**
* onStep is called when next value should be passed to
* a custom function.
*
* @param aFunctionArguments The arguments passed in to the function
*/
void onStep(in mozIStorageValueArray aFunctionArguments);
/**
* Called when all tuples in a group have been processed and the engine
* needs the aggregate function's value.
*
* @returns aggregate result as Variant.
*/
nsIVariant onFinal();
};