gecko-dev/xpcom/glue/nsIInterfaceRequestorUtils.h

50 lines
1.4 KiB
C++

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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 MOZ_STACK_CLASS nsGetInterface final : public nsCOMPtr_helper
{
public:
nsGetInterface(nsISupports* aSource, nsresult* aError)
: mSource(aSource)
, mErrorPtr(aError)
{
}
virtual nsresult NS_FASTCALL operator()(const nsIID&, void**) const
override;
private:
nsISupports* MOZ_NON_OWNING_REF mSource;
nsresult* mErrorPtr;
};
inline const nsGetInterface
do_GetInterface(nsISupports* aSource, nsresult* aError = 0)
{
return nsGetInterface(aSource, aError);
}
#endif // __nsInterfaceRequestorUtils_h