storage/public/mozIStorageAggregateFunction.idl

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* ***** BEGIN LICENSE BLOCK *****
   3  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
   4  *
   5  * The contents of this file are subject to the Mozilla Public License Version
   6  * 1.1 (the "License"); you may not use this file except in compliance with
   7  * the License. You may obtain a copy of the License at
   8  * http://www.mozilla.org/MPL/
   9  *
  10  * Software distributed under the License is distributed on an "AS IS" basis,
  11  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
  12  * for the specific language governing rights and limitations under the
  13  * License.
  14  *
  15  * The Original Code is Storage Code.
  16  *
  17  * The Initial Developer of the Original Code is
  18  *   Lev Serebryakov <lev@serebryakov.spb.ru>
  19  * Portions created by the Initial Developer are Copyright (C) 2007
  20  * the Initial Developer. All Rights Reserved.
  21  *
  22  * Contributor(s):
  23  *
  24  * Alternatively, the contents of this file may be used under the terms of
  25  * either the GNU General Public License Version 2 or later (the "GPL"), or
  26  * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
  27  * in which case the provisions of the GPL or the LGPL are applicable instead
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  33  * the provisions above, a recipient may use your version of this file under
  34  * the terms of any one of the MPL, the GPL or the LGPL.
  35  *
  36  * ***** END LICENSE BLOCK ***** */
  37
  38 #include "nsISupports.idl"
  39
  40 interface mozIStorageConnection;
  41 interface mozIStorageValueArray;
  42 interface nsIArray;
  43 interface nsIVariant;
  44
  45 /**
  46  * mozIStorageAggregateFunction represents aggregate SQL function.
  47  * Common examples of aggregate functions are SUM() and COUNT().
  48  *
  49  * An aggregate function calculates one result for a given set of data, where
  50  * a set of data is a group of tuples. There can be one group
  51  * per request or many of them, if GROUP BY clause is used or not.
  52  */
  53 [scriptable, uuid(763217b7-3123-11da-918d-000347412e16)]
  54 interface mozIStorageAggregateFunction : nsISupports {
  55   /**
  56    * onStep is called when next value should be passed to
  57    * a custom function.
  58    *
  59    * @param aFunctionArguments    The arguments passed in to the function
  60    */
  61   void onStep(in mozIStorageValueArray aFunctionArguments);
  62
  63   /**
  64    * Called when all tuples in a group have been processed and the engine
  65    * needs the aggregate function's value.
  66    *
  67    * @returns aggregate result as Variant.
  68    */
  69   nsIVariant onFinal();
  70 };