gecko-dev/xpcom/base/nsIInterfaceRequestorUtils.h

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/* -*- Mode: IDL; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
*
* 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 the Mozilla browser.
*
* The Initial Developer of the Original Code is Netscape
* Communications, Inc. Portions created by Netscape are
* Copyright (C) 1999, Mozilla. All Rights Reserved.
*
* Contributor(s):
*/
#ifndef __nsInterfaceRequestorUtils_h
#define __nsInterfaceRequestorUtils_h
#include "nsCOMPtr.h"
// a type-safe shortcut for calling the |GetInterface()| member function
// T must inherit from nsIInterfaceRequestor, but the cast may be ambiguous.
template <class T, class DestinationType>
inline
nsresult
CallGetInterface( T* aSource, DestinationType** aDestination )
{
NS_PRECONDITION(aSource, "null parameter");
NS_PRECONDITION(aDestination, "null parameter");
return aSource->GetInterface(NS_GET_IID(DestinationType),
NS_REINTERPRET_CAST(void**, aDestination));
}
class NS_EXPORT nsGetInterface : public nsCOMPtr_helper
{
public:
nsGetInterface( nsISupports* aSource, nsresult* error )
: mSource(aSource),
mErrorPtr(error)
{
// nothing else to do here
}
virtual nsresult operator()( const nsIID&, void** ) const;
virtual ~nsGetInterface() {};
private:
nsCOMPtr<nsISupports> mSource;
nsresult* mErrorPtr;
};
inline
const nsGetInterface
do_GetInterface( nsISupports* aSource, nsresult* error = 0 )
{
return nsGetInterface(aSource, error);
}
#endif // __nsInterfaceRequestorUtils_h