Should answer 1.

2. QI does addref

1. You plan to use return value instead of outparam to fetch QI result. Will the result still be addref’ed?

2. Smart pointers like nsCOMPtr are facilitating RAII design pattern. One assigns all acquired resources to such pointers, uses the resources as long as it makes sense, and forgets about the resources as they lose value. Smart pointers do the rest of the job – releasing.

I assume that if QI is not addref’ing, then if I use a smart pointer once, the reference I hold becomes owning. If I pass it further, it will always be addref’ed thereafter.

If the above paragraph is correct, maybe it makes sense to introduce a third method to deal with reference counting like ‘Unref()’ which will reduce refcount, but won’t cause destruction. And nsReturnPtr smart pointer which will call Unref() instead of Release(), thus bringing the return value resource to pristine ‘unsmarted’ state and allowing to pass it further as a raw pointer.