Issues in typelib.c with installshield 7

[Andrew de Quincey]

Hi, today I've been trying to get an Installshield 7 installer going. I think 
I've seen reports from other people about having problems as well.

The problems I've been having stem from the implementation of 
ITypeLib/ITypeInfo/etc in oleaut32. The first problem is as follows:

Installshield has a TLB which contains a type hiererachy as follows:
IDispatch
: ISomething
: : ISomething2

An instance of ISomething2 is created. Installshield attempts to look up a 
method which is only defined in ISomething. The lookup fails. This is because 
ISomething and ISomething2 inherit from IDispatch, and are marked as 
TKIND_DISPATCH in the typelib. However in the code, an upwards traversal of 
the type hierarchy is only done for the TKIND_INTERFACE.

I've experimented with modifying the code so that it also does an upward 
traversal for TKIND_DISPATCH as well (as they are still interfaces which can 
inherit). It now finds the methods/values properly. (It still doesn't work as 
there are then reference count problems, but I'm looking into that.)

However, can anyone confirm if my experimental modification is the correct 
behaviour?

e.g. in ITypeInfo_fnGetIDsOfNames, I have changed it to
    if(This->TypeAttr.cImplTypes &&
       (This->TypeAttr.typekind==TKIND_INTERFACE || 
This->TypeAttr.typekind==TKIND_DISPATCH)) {

[Marcus Meissner]

On Sun, Dec 07, 2003 at 03:37:17PM +0000, Andrew de Quincey wrote:
> Hi, today I've been trying to get an Installshield 7 installer going. I think 
> I've seen reports from other people about having problems as well.
>
> The problems I've been having stem from the implementation of 
> ITypeLib/ITypeInfo/etc in oleaut32. The first problem is as follows:
>
> Installshield has a TLB which contains a type hiererachy as follows:
> IDispatch
> : ISomething
> : : ISomething2
>
> An instance of ISomething2 is created. Installshield attempts to look up a 
> method which is only defined in ISomething. The lookup fails. This is because 
> ISomething and ISomething2 inherit from IDispatch, and are marked as 
> TKIND_DISPATCH in the typelib. However in the code, an upwards traversal of 
> the type hierarchy is only done for the TKIND_INTERFACE.
>
> I've experimented with modifying the code so that it also does an upward 
> traversal for TKIND_DISPATCH as well (as they are still interfaces which can 
> inherit). It now finds the methods/values properly. (It still doesn't work as 
> there are then reference count problems, but I'm looking into that.)
>
> However, can anyone confirm if my experimental modification is the correct 
> behaviour?
>
> e.g. in ITypeInfo_fnGetIDsOfNames, I have changed it to
>     if(This->TypeAttr.cImplTypes &&
>        (This->TypeAttr.typekind==TKIND_INTERFACE || 
> This->TypeAttr.typekind==TKIND_DISPATCH)) {

Do you have a sample installer for download?

Ciao, Marcus

[Andrew de Quincey]

> > e.g. in ITypeInfo_fnGetIDsOfNames, I have changed it to
> >     if(This->TypeAttr.cImplTypes &&
> >        (This->TypeAttr.typekind==TKIND_INTERFACE ||
> > This->TypeAttr.typekind==TKIND_DISPATCH)) {
>
> Do you have a sample installer for download?

Bah, I can't find one thats (a) available easily (b) free, and (c) has the 
same problem.

However, I AM writing you a sample winelib program which demonstrates the 
problem using the installshield typelib... I'll send it to you in a moment.

[Marcus Meissner]

On Mon, Dec 08, 2003 at 10:39:54AM +0000, Andrew de Quincey wrote:
> > > e.g. in ITypeInfo_fnGetIDsOfNames, I have changed it to
> > >     if(This->TypeAttr.cImplTypes &&
> > >        (This->TypeAttr.typekind==TKIND_INTERFACE ||
> > > This->TypeAttr.typekind==TKIND_DISPATCH)) {
> >
> > Do you have a sample installer for download?
>
> Bah, I can't find one thats (a) available easily (b) free, and (c) has the 
> same problem.
>
> However, I AM writing you a sample winelib program which demonstrates the 
> problem using the installshield typelib... I'll send it to you in a moment.

I think the change is good. Please submit. :)

Ciao, Marcus

[Andrew de Quincey]

On Monday 08 December 2003 21:22, Marcus Meissner wrote:
> On Mon, Dec 08, 2003 at 10:39:54AM +0000, Andrew de Quincey wrote:
> > > > e.g. in ITypeInfo_fnGetIDsOfNames, I have changed it to
> > > >     if(This->TypeAttr.cImplTypes &&
> > > >        (This->TypeAttr.typekind==TKIND_INTERFACE ||
> > > > This->TypeAttr.typekind==TKIND_DISPATCH)) {
> > >
> > > Do you have a sample installer for download?
> >
> > Bah, I can't find one thats (a) available easily (b) free, and (c) has
> > the same problem.
> >
> > However, I AM writing you a sample winelib program which demonstrates the
> > problem using the installshield typelib... I'll send it to you in a
> > moment.
>
> I think the change is good. Please submit. :)

Cool, glad you agree :)

Next up is some reference count problem; the ITypeLib interface seems to get 
destroyed too early.

[Mike Hearn]

On Tue, 09 Dec 2003 18:22:04 +0000, Andrew de Quincey wrote:
> Next up is some reference count problem; the ITypeLib interface seems to get 
> destroyed too early.

Hmmm. I seem to recall posting a patch that fixed a similar issue (but in
the wrong way) a few months ago. I think TypeInfo was not reffing its
containing TypeLib or something like that. I don't remember if it was
fixed by somebody else or not.... sorry I can't be more help, but that
might be somewhere to start looking.

[Andrew de Quincey]

On Tuesday 09 December 2003 20:02, Mike Hearn wrote:
> On Tue, 09 Dec 2003 18:22:04 +0000, Andrew de Quincey wrote:
> > Next up is some reference count problem; the ITypeLib interface seems to
> > get destroyed too early.
>
> Hmmm. I seem to recall posting a patch that fixed a similar issue (but in
> the wrong way) a few months ago. I think TypeInfo was not reffing its
> containing TypeLib or something like that. I don't remember if it was
> fixed by somebody else or not.... sorry I can't be more help, but that
> might be somewhere to start looking.

Yeah, I've played with it under windows... an ITypeInfo is supposed to 
AddRef() the ITypeLib ONCE when its retrieved using things like 
ITypeLib.FindName(). (when you release it, you do it just once as well, when 
the original refcount at which it was AddRef()ed is reached). This ain't 
happening. Yet.

I've also found a number of other bugs in that file; specifically theres a lot 
of confusion between BSTR and OLESTR going on, which really really knackers 
things. Easy to do though: they've just confused the hell out of me!! So a 
BSTR is the same type as an OLESTR to the C compiler, EXCEPT it has a fancy 
hidden DWORD before the actual buffer giving the number of bytes used! Thats 
not at all confusing is it?

[Mike Hearn]

On Wed, 2003-12-10 at 00:12, Andrew de Quincey wrote:
> Yeah, I've played with it under windows... an ITypeInfo is supposed to 
> AddRef() the ITypeLib ONCE when its retrieved using things like 
> ITypeLib.FindName(). (when you release it, you do it just once as well, when 
> the original refcount at which it was AddRef()ed is reached). This ain't 
> happening. Yet.

I don't remember exactly what I did, but I remember it being classed as
"wrong" somehow... I expect it was reffing things too many times.
> I've also found a number of other bugs in that file; specifically theres a lot 
> of confusion between BSTR and OLESTR going on, which really really knackers 
> things. Easy to do though: they've just confused the hell out of me!! So a 
> BSTR is the same type as an OLESTR to the C compiler, EXCEPT it has a fancy 
> hidden DWORD before the actual buffer giving the number of bytes used! Thats 
> not at all confusing is it?

Indeed. BSTR is quite possibly the most moronic string type I've ever
seen.

For the interested lurkers amongst us, here is a useful guide to BSTR
semantics I stumbled across some time ago. They use it internally in
Redmond:

http://blogs.gotdotnet.com/ericli/PermaLink.aspx/853ae05f-7610-4531-ab1b-070...

It's good to have another person who understands OLE on board! I spent
months getting to grips with the darn thing, and now I don't have any
spare time to work on it :(