gecko-dev/xpcom/ds/nsEmptyEnumerator.cpp

78 lines
2.0 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 1.0 (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.
*/
/*
An empty enumerator.
*/
#include "nsIEnumerator.h"
static NS_DEFINE_IID(kISupportsIID, NS_ISUPPORTS_IID);
////////////////////////////////////////////////////////////////////////
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(nsISimpleEnumerator::GetIID()) ||
iid.Equals(kISupportsIID)) {
*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;
}