gecko-dev/xpcom/ds/nsEmptyEnumerator.cpp

81 lines
2.1 KiB
C++

/* -*- 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):
* Pierre Phaneuf <pp@ludusdesign.com>
*/
/*
An empty enumerator.
*/
#include "nsIEnumerator.h"
////////////////////////////////////////////////////////////////////////
class EmptyEnumeratorImpl : public nsISimpleEnumerator
{
public:
EmptyEnumeratorImpl(void) {};
virtual ~EmptyEnumeratorImpl(void) {};
// nsISupports interface
NS_IMETHOD_(nsrefcnt) AddRef(void) {
return 2;
}
NS_IMETHOD_(nsrefcnt) Release(void) {
return 1;
}
NS_IMETHOD QueryInterface(REFNSIID iid, void** result) {
if (! result)
return NS_ERROR_NULL_POINTER;
if (iid.Equals(NS_GET_IID(nsISimpleEnumerator)) ||
iid.Equals(NS_GET_IID(nsISupports))) {
*result = (nsISimpleEnumerator*) this;
NS_ADDREF(this);
return NS_OK;
}
return NS_NOINTERFACE;
}
// nsISimpleEnumerator
NS_IMETHOD HasMoreElements(PRBool* aResult) {
*aResult = PR_FALSE;
return NS_OK;
}
NS_IMETHOD GetNext(nsISupports** aResult) {
return NS_ERROR_UNEXPECTED;
}
};
extern "C" NS_COM nsresult
NS_NewEmptyEnumerator(nsISimpleEnumerator** aResult)
{
static EmptyEnumeratorImpl gEmptyEnumerator;
*aResult = &gEmptyEnumerator;
return NS_OK;
}