416212 - Elsa: parse nsDragService.ii

Status: RESOLVED FIXED

(Developer Infrastructure :: Source Code Analysis, defect)

Description

[David Mandelin [:dmandelin]]

This file can't be parsed. It's not clear what the problem is, but it looks like Elsa is too restrictive in checking some usage of nsCOMPtr. This problem actually existed even with gcc 3.4 headers.

Comment 1

[David Mandelin [:dmandelin]]

The problem is that at nsDragService.cpp:204, where mSelection (which is an nsCOMPtr<ISelection>) is used in a context requiring a boolean, Elsa seems to have chosen to add a conversion to nsDerivedSafe<ISelection> to allow the comparison. nsDerivedSafe<ISelection> inherits ISelection, which is incomplete in this file, so it is an error. Now I need to find out what it should really be converting to according to C++ and make Elsa do that.

Comment 2

[David Mandelin [:dmandelin]]

Fixed. In detail, the problem was that the correct C++ conversion gets a value of type 'nsDerivedSafe<ISelection>*' for use in the boolean. ISelection isn't defined here, but that's fine because this is a pointer type.

Elsa just went ahead and tried to instantiate the type nsDerivedSafe<ISelection>, because in some situations, you can get a needed conversion only by instantiating the type. (Specifically, if you were trying to pass to an ISelection*.)

I changed Elsa so that it still tries to instantiate, in case it helps, but if instantiation fails, it doesn't complain about it.