248017 - Cannot get to ISimpleDOM* interfaces on Windows XP

Status: RESOLVED FIXED

(Core :: Disability Access APIs, defect)

Description

[Aaron Leventhal]

On Windows XP, QueryInterface is not allowed from IAccessible to a custom
interface. The docs on MSDN even say that IServiceProvider::QueryService() must
be used, but don't say why.

Unfortunately we don't currently make it possible to use all of the ISimpleDOM*
interfaces from QueryService.

Comment 1

[Aaron Leventhal]

Attachment: Support any of our interfaces via QueryInterface or IServiceProvider::QueryService.() We ignore the refguid argument.

I tested this using the code written up in the comments.

Comment 2

[Darin Fisher]

Comment on attachment 151404 [details] [diff] [review]
Support any of our interfaces via QueryInterface or IServiceProvider::QueryService.() We ignore the refguid argument.

>Index: accessible/src/msaa/nsAccessibleWrap.cpp

> nsAccessibleWrap::QueryService(REFGUID guidService, REFIID iid, void** ppv)
...
>+  *ppv = NULL;
>+  return QueryInterface(iid, ppv);
> }

The first thing QueryInterface seems to do is set *ppv to NULL, so perhaps
it is redundant here to also set *ppv to NULL.	Or, are you worried that
someone might subclass nsAccessibleWrap and reimplement QueryInterface such
that it doesn't set *ppv to NULL up front?

sr=darin either way

Comment 3

[Aaron Leventhal]

/cvsroot/mozilla/accessible/src/msaa/nsAccessibleWrap.cpp,v  <-- 
nsAccessibleWrap.cpp
new revision: 1.11; previous revision: 1.10
done

Comment 4

[Firefox Bug Husbandry Bot]

https://bugzilla.mozilla.org/show_bug.cgi?id=1527381