gecko-dev/xpcom/public/nsIEnumerator.h
1999-03-11 10:47:54 +00:00

105 lines
3.8 KiB
C++

/* -*- 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"
#define NS_IENUMERATOR_IID \
{ /* ad385286-cbc4-11d2-8cca-0060b0fc14a3 */ \
0xad385286, \
0xcbc4, \
0x11d2, \
{0x8c, 0xca, 0x00, 0x60, 0xb0, 0xfc, 0x14, 0xa3} \
}
class nsIEnumerator : public nsISupports {
public:
static const nsIID& GetIID(void) { static nsIID iid = NS_IENUMERATOR_IID; return iid; }
/** First will reset the list. will return NS_FAILED if no items
*/
NS_IMETHOD First(void) = 0;
/** Next will advance the list. will return failed if already at end
*/
NS_IMETHOD Next(void) = 0;
/** CurrentItem will return the CurrentItem item it will fail if the list is empty
* @param aItem return value
*/
NS_IMETHOD 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
*/
NS_IMETHOD IsDone(void) = 0;
};
#define NS_IBIDIRECTIONALENUMERATOR_IID \
{ /* 75f158a0-cadd-11d2-8cca-0060b0fc14a3 */ \
0x75f158a0, \
0xcadd, \
0x11d2, \
{0x8c, 0xca, 0x00, 0x60, 0xb0, 0xfc, 0x14, 0xa3} \
}
class nsIBidirectionalEnumerator : public nsIEnumerator {
public:
static const nsIID& GetIID(void) { static nsIID iid = NS_IBIDIRECTIONALENUMERATOR_IID; return iid; }
/** Last will reset the list to the end. will return NS_FAILED if no items
*/
NS_IMETHOD Last(void) = 0;
/** Prev will decrement the list. will return failed if already at beginning
*/
NS_IMETHOD Prev(void) = 0;
};
// Construct and return an implementation of a "conjoining enumerator." This
// enumerator lets you string together two other enumerators into one sequence.
// The result is an nsIBidirectionalEnumerator, but if either input is not
// also bidirectional, the Last and Prev operations will fail.
extern "C" NS_COM nsresult
NS_NewConjoiningEnumerator(nsIEnumerator* first, nsIEnumerator* second,
nsIBidirectionalEnumerator* *aInstancePtrResult);
// Construct and return an implementation of a "union enumerator." This
// enumerator will only return elements that are found in both constituent
// enumerators.
extern "C" NS_COM nsresult
NS_NewUnionEnumerator(nsIEnumerator* first, nsIEnumerator* second,
nsIEnumerator* *aInstancePtrResult);
// Construct and return an implementation of an "intersection enumerator." This
// enumerator will return elements that are found in either constituent
// enumerators, eliminating duplicates.
extern "C" NS_COM nsresult
NS_NewIntersectionEnumerator(nsIEnumerator* first, nsIEnumerator* second,
nsIEnumerator* *aInstancePtrResult);
#endif // __nsIEnumerator_h