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lightning-sunbird  0.9+nobinonly
nsEmptyEnumerator.cpp
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00001 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
00002 /* ***** BEGIN LICENSE BLOCK *****
00003  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
00004  *
00005  * The contents of this file are subject to the Mozilla Public License Version
00006  * 1.1 (the "License"); you may not use this file except in compliance with
00007  * the License. You may obtain a copy of the License at
00008  * http://www.mozilla.org/MPL/
00009  *
00010  * Software distributed under the License is distributed on an "AS IS" basis,
00011  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
00012  * for the specific language governing rights and limitations under the
00013  * License.
00014  *
00015  * The Original Code is mozilla.org code.
00016  *
00017  * The Initial Developer of the Original Code is
00018  * Netscape Communications Corporation.
00019  * Portions created by the Initial Developer are Copyright (C) 1998
00020  * the Initial Developer. All Rights Reserved.
00021  *
00022  * Contributor(s):
00023  *   L. David Baron <dbaron@dbaron.org>
00024  *   Pierre Phaneuf <pp@ludusdesign.com>
00025  *
00026  * Alternatively, the contents of this file may be used under the terms of
00027  * either of the GNU General Public License Version 2 or later (the "GPL"),
00028  * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
00029  * in which case the provisions of the GPL or the LGPL are applicable instead
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00037  *
00038  * ***** END LICENSE BLOCK ***** */
00039 
00040 /*
00041 
00042   An empty enumerator.
00043 
00044  */
00045 
00046 #include "nsEmptyEnumerator.h"
00047 
00049 
00050 MOZ_DECL_CTOR_COUNTER(EmptyEnumeratorImpl)
00051 
00052 EmptyEnumeratorImpl::EmptyEnumeratorImpl(void)
00053 {
00054     MOZ_COUNT_CTOR(EmptyEnumeratorImpl);
00055 }
00056 
00057 EmptyEnumeratorImpl::~EmptyEnumeratorImpl(void)
00058 {
00059     MOZ_COUNT_DTOR(EmptyEnumeratorImpl);
00060 }
00061 
00062 // nsISupports interface
00063 NS_IMETHODIMP_(nsrefcnt) EmptyEnumeratorImpl::AddRef(void)
00064 {
00065     return 2;
00066 }
00067 
00068 NS_IMETHODIMP_(nsrefcnt) EmptyEnumeratorImpl::Release(void)
00069 {
00070     return 1;
00071 }
00072 
00073 NS_IMPL_QUERY_INTERFACE1(EmptyEnumeratorImpl, nsISimpleEnumerator)
00074 
00075 
00076 // nsISimpleEnumerator interface
00077 NS_IMETHODIMP EmptyEnumeratorImpl::HasMoreElements(PRBool* aResult)
00078 {
00079     *aResult = PR_FALSE;
00080     return NS_OK;
00081 }
00082 
00083 NS_IMETHODIMP EmptyEnumeratorImpl::HasMore(PRBool* aResult)
00084 {
00085     *aResult = PR_FALSE;
00086     return NS_OK;
00087 }
00088 
00089 NS_IMETHODIMP EmptyEnumeratorImpl::GetNext(nsISupports** aResult)
00090 {
00091     return NS_ERROR_UNEXPECTED;
00092 }
00093 
00094 NS_IMETHODIMP EmptyEnumeratorImpl::GetNext(nsACString& aResult)
00095 {
00096     return NS_ERROR_UNEXPECTED;
00097 }
00098 
00099 NS_IMETHODIMP EmptyEnumeratorImpl::GetNext(nsAString& aResult)
00100 {
00101     return NS_ERROR_UNEXPECTED;
00102 }
00103 
00104 static EmptyEnumeratorImpl* gEmptyEnumerator = nsnull;
00105 
00106 extern "C" NS_COM nsresult
00107 NS_NewEmptyEnumerator(nsISimpleEnumerator** aResult)
00108 {
00109     nsresult rv = NS_OK;
00110     if (!gEmptyEnumerator) {
00111         gEmptyEnumerator = new EmptyEnumeratorImpl();
00112         if (!gEmptyEnumerator)
00113             rv = NS_ERROR_OUT_OF_MEMORY;
00114     }
00115     *aResult = gEmptyEnumerator;
00116     return rv;
00117 }
00118 
00119 /* static */ void
00120 EmptyEnumeratorImpl::Shutdown()
00121 {
00122     delete gEmptyEnumerator;
00123     gEmptyEnumerator = nsnull;
00124 }