Re: [PATCH v2 1/2] oleacc: Implement AccessibleObjectFromEvent.

[Piotr Caban]

Hi Connor,

On 8/27/21 5:21 PM, Connor McAdams wrote:
> +HRESULT WINAPI AccessibleObjectFromEvent( HWND hwnd, DWORD object_id, DWORD child_id,
> -
>                         IAccessible **acc_out, VARIANT *child_id_out )
>
> +{
> - VARIANT child_id_variant;
> - IAccessible *acc = NULL;
> - IDispatch *child = NULL;
> - HRESULT hr;
> -
> - TRACE("%p %d %d %p %p\n", hwnd, object_id, child_id, acc_out, child_id_out);
> -
> - if (!acc_out)
> -
>    return E_INVALIDARG;
> - *acc_out = NULL;

child_id_out should be also zeroed at this point.
> -
> - hr = AccessibleObjectFromWindow(hwnd, object_id, &IID_IAccessible, (void **)&acc);
> - if (FAILED(hr))
> -
>    return hr;
> -
> - variant_init_i4(&child_id_variant, child_id);
> - hr = IAccessible_get_accChild(acc, child_id_variant, &child);
> - if (FAILED(hr))
> -
>    TRACE("get_accChild failed with %#x!\n", hr);
> -
> - if (child)

A bad behaving IAccessible implementation may set child and return 
error. Please change it to something like:
if (SUCCEEDED(hr) && child)
> - {
> -
>    IAccessible_Release(acc);
> -
> -
>    IDispatch_QueryInterface(child, &IID_IAccessible, (void **)&acc);

Please handle QueryInterface failure here.

Thanks,
Piotr