gecko-dev/xpcom/glue/nsIInterfaceRequestorUtils.h
2012-05-21 12:12:37 +01:00

52 lines
1.5 KiB
C++

/* -*- Mode: IDL; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#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_TEMPLATE_IID(DestinationType),
reinterpret_cast<void**>(aDestination));
}
class NS_COM_GLUE nsGetInterface : public nsCOMPtr_helper
{
public:
nsGetInterface( nsISupports* aSource, nsresult* error )
: mSource(aSource),
mErrorPtr(error)
{
// nothing else to do here
}
virtual nsresult NS_FASTCALL operator()( const nsIID&, void** ) const;
private:
nsISupports* mSource;
nsresult* mErrorPtr;
};
inline
const nsGetInterface
do_GetInterface( nsISupports* aSource, nsresult* error = 0 )
{
return nsGetInterface(aSource, error);
}
#endif // __nsInterfaceRequestorUtils_h