gecko-dev/xpcom/ds/nsIEnumerator.h

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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/*
* The contents of this file are subject to the Netscape Public License
* Version 1.0 (the "NPL"); you may not use this file except in
* compliance with the NPL. You may obtain a copy of the NPL at
* http://www.mozilla.org/NPL/
*
* Software distributed under the NPL is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the NPL
* for the specific language governing rights and limitations under the
* NPL.
*
* The Initial Developer of this code under the NPL is Netscape
* Communications Corporation. Portions created by Netscape are
* Copyright (C) 1998 Netscape Communications Corporation. All Rights
* Reserved.
*/
#ifndef nsIEnumerator_h___
#define nsIEnumerator_h___
#include "nsISupports.h"
// {646F4FB0-B1F2-11d1-AA29-000000000000}
#define NS_IENUMERATOR_IID \
{0x646f4fb0, 0xb1f2, 0x11d1, \
{ 0xaa, 0x29, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0 } }
class nsIEnumerator : public nsISupports {
public:
static const nsIID& IID() { static nsIID iid = NS_IENUMERATOR_IID; return iid; }
/** First will reset the list. will return NS_FAILED if no items
*/
virtual nsresult First()=0;
/** Last will reset the list to the end. will return NS_FAILED if no items
*/
virtual nsresult Last()=0;
/** Next will advance the list. will return failed if allready at end
*/
virtual nsresult Next()=0;
/** Prev will decrement the list. will return failed if allready at beginning
*/
virtual nsresult Prev()=0;
/** CurrentItem will return the CurrentItem item it will fail if the list is empty
* @param aItem return value
*/
virtual nsresult CurrentItem(nsISupports **aItem)=0;
/** return if the collection is at the end. that is the beginning following a call to Prev
* and it is the end of the list following a call to next
* @param aItem return value
*/
virtual nsresult IsDone()=0;
};
#endif // __nsIEnumerator_h