michael@0: /* -*- Mode: IDL; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
michael@0:  *
michael@0:  * This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #ifndef __nsInterfaceRequestorUtils_h
michael@0: #define __nsInterfaceRequestorUtils_h
michael@0: 
michael@0: #include "nsCOMPtr.h"
michael@0: 
michael@0: // a type-safe shortcut for calling the |GetInterface()| member function
michael@0: // T must inherit from nsIInterfaceRequestor, but the cast may be ambiguous.
michael@0: template <class T, class DestinationType>
michael@0: inline
michael@0: nsresult
michael@0: CallGetInterface( T* aSource, DestinationType** aDestination )
michael@0:   {
michael@0:     NS_PRECONDITION(aSource, "null parameter");
michael@0:     NS_PRECONDITION(aDestination, "null parameter");
michael@0: 
michael@0:     return aSource->GetInterface(NS_GET_TEMPLATE_IID(DestinationType),
michael@0:                                  reinterpret_cast<void**>(aDestination));
michael@0:   }
michael@0: 
michael@0: class NS_COM_GLUE nsGetInterface : public nsCOMPtr_helper
michael@0:   {
michael@0:     public:
michael@0:       nsGetInterface( nsISupports* aSource, nsresult* error )
michael@0:           : mSource(aSource),
michael@0:             mErrorPtr(error)
michael@0:         {
michael@0:           // nothing else to do here
michael@0:         }
michael@0: 
michael@0:       virtual nsresult NS_FASTCALL operator()( const nsIID&, void** ) const;
michael@0: 
michael@0:     private:
michael@0:       nsISupports*          mSource;
michael@0:       nsresult*             mErrorPtr;
michael@0:   };
michael@0: 
michael@0: inline
michael@0: const nsGetInterface
michael@0: do_GetInterface( nsISupports* aSource, nsresult* error = 0 )
michael@0:   {
michael@0:     return nsGetInterface(aSource, error);
michael@0:   }
michael@0: 
michael@0: #endif // __nsInterfaceRequestorUtils_h
michael@0: