gecko-dev/xpcom/glue/nsEnumeratorUtils.cpp

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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla 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/MPL/
*
* 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 the Initial Developer are Copyright (C) 1998
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Benjamin Smedberg <benjamin@smedbergs.us>
*
* Code moved from nsEmptyEnumerator.cpp:
* L. David Baron <dbaron@dbaron.org>
* Pierre Phaneuf <pp@ludusdesign.com>
*
* Alternatively, the contents of this file may be used under the terms of
* either of the GNU General Public License Version 2 or later (the "GPL"),
* or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
#include "nsEnumeratorUtils.h"
#include "nsISimpleEnumerator.h"
#include "nsIStringEnumerator.h"
#include "nsCOMPtr.h"
class EmptyEnumeratorImpl : public nsISimpleEnumerator,
public nsIUTF8StringEnumerator,
public nsIStringEnumerator
{
public:
// nsISupports interface
NS_DECL_ISUPPORTS_INHERITED // not really inherited, but no mRefCnt
// nsISimpleEnumerator
NS_DECL_NSISIMPLEENUMERATOR
NS_DECL_NSIUTF8STRINGENUMERATOR
// can't use NS_DECL_NSISTRINGENUMERATOR because they share the
// HasMore() signature
NS_IMETHOD GetNext(nsAString& aResult);
static EmptyEnumeratorImpl* GetInstance() {
return const_cast<EmptyEnumeratorImpl*>(&kInstance);
}
private:
static const EmptyEnumeratorImpl kInstance;
};
// nsISupports interface
NS_IMETHODIMP_(nsrefcnt) EmptyEnumeratorImpl::AddRef(void)
{
return 2;
}
NS_IMETHODIMP_(nsrefcnt) EmptyEnumeratorImpl::Release(void)
{
return 1;
}
NS_IMPL_QUERY_INTERFACE3(EmptyEnumeratorImpl, nsISimpleEnumerator,
nsIUTF8StringEnumerator, nsIStringEnumerator)
// nsISimpleEnumerator interface
NS_IMETHODIMP EmptyEnumeratorImpl::HasMoreElements(PRBool* aResult)
{
*aResult = PR_FALSE;
return NS_OK;
}
NS_IMETHODIMP EmptyEnumeratorImpl::HasMore(PRBool* aResult)
{
*aResult = PR_FALSE;
return NS_OK;
}
NS_IMETHODIMP EmptyEnumeratorImpl::GetNext(nsISupports** aResult)
{
return NS_ERROR_UNEXPECTED;
}
NS_IMETHODIMP EmptyEnumeratorImpl::GetNext(nsACString& aResult)
{
return NS_ERROR_UNEXPECTED;
}
NS_IMETHODIMP EmptyEnumeratorImpl::GetNext(nsAString& aResult)
{
return NS_ERROR_UNEXPECTED;
}
const EmptyEnumeratorImpl EmptyEnumeratorImpl::kInstance;
nsresult
NS_NewEmptyEnumerator(nsISimpleEnumerator** aResult)
{
*aResult = EmptyEnumeratorImpl::GetInstance();
return NS_OK;
}
////////////////////////////////////////////////////////////////////////////////
class nsSingletonEnumerator : public nsISimpleEnumerator
{
public:
NS_DECL_ISUPPORTS
// nsISimpleEnumerator methods
NS_IMETHOD HasMoreElements(PRBool* aResult);
NS_IMETHOD GetNext(nsISupports** aResult);
nsSingletonEnumerator(nsISupports* aValue);
private:
~nsSingletonEnumerator();
protected:
nsISupports* mValue;
PRBool mConsumed;
};
nsSingletonEnumerator::nsSingletonEnumerator(nsISupports* aValue)
: mValue(aValue)
{
NS_IF_ADDREF(mValue);
mConsumed = (mValue ? PR_FALSE : PR_TRUE);
}
nsSingletonEnumerator::~nsSingletonEnumerator()
{
NS_IF_RELEASE(mValue);
}
NS_IMPL_ISUPPORTS1(nsSingletonEnumerator, nsISimpleEnumerator)
NS_IMETHODIMP
nsSingletonEnumerator::HasMoreElements(PRBool* aResult)
{
NS_PRECONDITION(aResult != 0, "null ptr");
if (! aResult)
return NS_ERROR_NULL_POINTER;
*aResult = !mConsumed;
return NS_OK;
}
NS_IMETHODIMP
nsSingletonEnumerator::GetNext(nsISupports** aResult)
{
NS_PRECONDITION(aResult != 0, "null ptr");
if (! aResult)
return NS_ERROR_NULL_POINTER;
if (mConsumed)
return NS_ERROR_UNEXPECTED;
mConsumed = PR_TRUE;
*aResult = mValue;
NS_ADDREF(*aResult);
return NS_OK;
}
nsresult
NS_NewSingletonEnumerator(nsISimpleEnumerator* *result,
nsISupports* singleton)
{
nsSingletonEnumerator* enumer = new nsSingletonEnumerator(singleton);
if (enumer == nsnull)
return NS_ERROR_OUT_OF_MEMORY;
*result = enumer;
NS_ADDREF(*result);
return NS_OK;
}
////////////////////////////////////////////////////////////////////////////////
class nsUnionEnumerator : public nsISimpleEnumerator
{
public:
NS_DECL_ISUPPORTS
// nsISimpleEnumerator methods
NS_IMETHOD HasMoreElements(PRBool* aResult);
NS_IMETHOD GetNext(nsISupports** aResult);
nsUnionEnumerator(nsISimpleEnumerator* firstEnumerator,
nsISimpleEnumerator* secondEnumerator);
private:
~nsUnionEnumerator();
protected:
nsCOMPtr<nsISimpleEnumerator> mFirstEnumerator, mSecondEnumerator;
PRBool mConsumed;
PRBool mAtSecond;
};
nsUnionEnumerator::nsUnionEnumerator(nsISimpleEnumerator* firstEnumerator,
nsISimpleEnumerator* secondEnumerator)
: mFirstEnumerator(firstEnumerator),
mSecondEnumerator(secondEnumerator),
mConsumed(PR_FALSE), mAtSecond(PR_FALSE)
{
}
nsUnionEnumerator::~nsUnionEnumerator()
{
}
NS_IMPL_ISUPPORTS1(nsUnionEnumerator, nsISimpleEnumerator)
NS_IMETHODIMP
nsUnionEnumerator::HasMoreElements(PRBool* aResult)
{
NS_PRECONDITION(aResult != 0, "null ptr");
if (! aResult)
return NS_ERROR_NULL_POINTER;
nsresult rv;
if (mConsumed) {
*aResult = PR_FALSE;
return NS_OK;
}
if (! mAtSecond) {
rv = mFirstEnumerator->HasMoreElements(aResult);
if (NS_FAILED(rv)) return rv;
if (*aResult)
return NS_OK;
mAtSecond = PR_TRUE;
}
rv = mSecondEnumerator->HasMoreElements(aResult);
if (NS_FAILED(rv)) return rv;
if (*aResult)
return NS_OK;
*aResult = PR_FALSE;
mConsumed = PR_TRUE;
return NS_OK;
}
NS_IMETHODIMP
nsUnionEnumerator::GetNext(nsISupports** aResult)
{
NS_PRECONDITION(aResult != 0, "null ptr");
if (! aResult)
return NS_ERROR_NULL_POINTER;
if (mConsumed)
return NS_ERROR_UNEXPECTED;
if (! mAtSecond)
return mFirstEnumerator->GetNext(aResult);
return mSecondEnumerator->GetNext(aResult);
}
nsresult
NS_NewUnionEnumerator(nsISimpleEnumerator* *result,
nsISimpleEnumerator* firstEnumerator,
nsISimpleEnumerator* secondEnumerator)
{
*result = nsnull;
if (! firstEnumerator) {
*result = secondEnumerator;
} else if (! secondEnumerator) {
*result = firstEnumerator;
} else {
nsUnionEnumerator* enumer = new nsUnionEnumerator(firstEnumerator, secondEnumerator);
if (enumer == nsnull)
return NS_ERROR_OUT_OF_MEMORY;
*result = enumer;
}
NS_ADDREF(*result);
return NS_OK;
}