pjs/xpcom/ds/nsIEnumerator.idl

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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
*
* The contents of this file are subject to the Netscape 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/NPL/
*
* 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 mozilla.org code.
*
* The Initial Developer of the Original Code is Netscape
* Communications Corporation. Portions created by Netscape are
* Copyright (C) 1998 Netscape Communications Corporation. All
* Rights Reserved.
*
* Contributor(s):
*/
#include "nsISupports.idl"
%{C++
#define NS_ENUMERATOR_FALSE 1
%}
/**
* Used to enumerate over elements defined by its implementor.
* Although hasMoreElements() can be called independently of getNext(),
* getNext() must be pre-ceeded by a call to hasMoreElements(). There is
* no way to "reset" an enumerator, once you obtain one.
*
* @status FROZEN
* @version 1.0
*/
[scriptable, uuid(D1899240-F9D2-11D2-BDD6-000064657374)]
interface nsISimpleEnumerator : nsISupports {
/**
* Called to determine whether or not the enumerator has
* any elements that can be returned via getNext(). This method
* is generally used to determine whether or not to initiate or
* continue iteration over the enumerator, though it can be
* called without subsequent getNext() calls. Does not affect
* internal state of enumerator.
*
* @see getNext()
* @return PR_TRUE if there are remaining elements in the enumerator.
* PR_FALSE if there are no more elements in the enumerator.
*/
boolean hasMoreElements();
/**
* Called to retrieve the next element in the enumerator. The "next"
* element is the first element upon the first call. Must be
* pre-ceeded by a call to hasMoreElements() which returns PR_TRUE.
* This method is generally called within a loop to iterate over
* the elements in the enumerator.
*
* @see hasMoreElements()
* @return NS_OK if the call succeeded in returning a non-null
* value through the out parameter.
* NS_ERROR_FAILURE if there are no more elements
* to enumerate.
* @return the next element in the enumeration.
*/
nsISupports getNext();
};
/*
* DO NOT USE THIS INTERFACE. IT IS HORRIBLY BROKEN, USES NS_COMFALSE
* AND IS BASICALLY IMPOSSIBLE TO USE CORRECTLY THROUGH PROXIES OR
* XPCONNECT. IF YOU SEE NEW USES OF THIS INTERFACE IN CODE YOU ARE
* REVIEWING, YOU SHOULD INSIST ON nsISimpleEnumerator.
*
* DON'T MAKE ME COME OVER THERE.
*/
[scriptable, uuid(ad385286-cbc4-11d2-8cca-0060b0fc14a3)]
interface nsIEnumerator : nsISupports {
/** First will reset the list. will return NS_FAILED if no items
*/
void first();
/** Next will advance the list. will return failed if already at end
*/
void next();
/** CurrentItem will return the CurrentItem item it will fail if the
* list is empty
*/
nsISupports currentItem();
/** 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
*/
void isDone();
};
[uuid(75f158a0-cadd-11d2-8cca-0060b0fc14a3)]
interface nsIBidirectionalEnumerator : nsIEnumerator {
/** Last will reset the list to the end. will return NS_FAILED if no items
*/
void last();
/** Prev will decrement the list. will return failed if already at beginning
*/
void prev();
};
%{C++
extern "C" NS_COM nsresult
NS_NewEmptyEnumerator(nsISimpleEnumerator** aResult);
// 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);
%}