[rdnzl-devel] New versions 0.8.0/0.5.0 (was: bug in delegate adapter release mechanism)

[Edi Weitz]

Hi Dominic!

On Fri, 13 Jan 2006 00:29:08 +0000, "lisp" <lisp at spikeisland.com> wrote:

> I've tracked down what looks to be a bug in the mechanism for
> releasing delegate adapters.
>
> The foreign callable ReleaseDelegateAdapter is declared with a
> return type of ffi-void-pointer but tries to return the result of
> remhash - a boolean. On LWW (at least) this results in:
>
> Condition: T cannot be converted to foreign type :POINTER. Call to 
> SYSTEM::FOREIGN-CALLABLE-ENTRY-POINT-NEW-PROCESS-AUX (offset 21)  
>   SYSTEM::FUNC : RDNZL::%FOREIGN-CALLABLE/RELEASEDELEGATEADAPTER
>
> I would suggest changing it (and the corresponding initialisation
> and DLL code) to have a void return type:
>
> (ffi-define-callable (ReleaseDelegateAdapter ffi-void) 
>  ((index ffi-integer)) ;; remove entry from hash table if CLR is done with it
>  (remhash index *callback-hash*))
>
> Also, in DelegateAdapter.cpp you have a comment on the destructor
> that it doesn't appear to be working:
>
> // the destructor notifies Lisp that this instance is no longer used -
> // at least in theory, this doesn't seem to work right now
> DelegateAdapter::~DelegateAdapter() {  release(indexIntoLisp); }
>
> This may have beeen the caused by the callback/threading issues
> discussed recently.  At least it has certainly worked for me here
> (hence this bug report) when using a DLL based LWW image (many
> thanks for your recent example of this).  Perhaps the .NET GC is
> running in a different thread, so the callback was failing in a
> normal .EXE image?

Makes perfect sense to me.  I've updated both the Lisp and the C++
code according to your recommendations - see ChangeLogs below.

However, I'm a bit in a hurry and I couldn't figure out an easy
example which shows that ReleaseDelegateAdapter is actually called -
at least not from a DLL-based LWW image.  Could you please check if it
works and report back to the list if possible?

Thanks a lot,
Edi.



  Lisp code:
  ----------

  Version 0.8.0
  2006-01-13
  Fix mechanism which releases delegate adapters (thanks to Dominic Robinson)
  Updated to DLL version 0.5.0

  <http://weitz.de/files/RDNZL.tar.gz>


  C++ code (optional):
  --------------------

  Version 0.5.0
  2006-01-13
  Fix mechanism which releases delegate adapters (thanks to Dominic Robinson)

  <http://weitz.de/files/RDNZL_cpp.tar.gz>