[rdnzl-devel] RDNZL - bug in delegate adapter release mechanism

[lisp]

Hi Edi

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?

The full traceback from the bug above seems to support this - it shows 
LWW creating a new process to handle the callback:

CL-USER 4 : 1 > :bb
#<PACKAGE COMMON-LISP-USER>

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

Catch frame: MP::PROCESS-TAG

Catch frame: (NIL)

Binding frame:
  MP:*CURRENT-PROCESS* : NIL

Binding frame:  WIN32::*DDE-THREAD-INSTANCE* : #<unbound>

Binding frame:
  MQ::*ACTIONS-AFTER-SLEEPING* : NIL

Binding frame:
  MR::*ACTIONS-BEFORE-SLEEPING* : NIL

Binding frame:  SYSTEM::*READER-STATE* : #<unbound>

Binding frame:  *PACKAGE* : #<PACKAGE COMMON-LISP-USER>

Binding frame:  EDITOR::*CURRENT-BUFFER* : NIL

Binding frame:  EDITOR::*CURRENT-WINDOW* : NIL

Binding frame:  EDITOR::*EDITOR-STATE* : NIL

Binding frame:  EDITOR::*EDITOR-INPUT-STYLE* : #S(EDITOR:EDITOR-INPUT-
STYLE :KEY-BINDINGS #<EDITOR::KEY-TABLE #<EQUALP Hash Table{332}
20BCA90C> 1 331> :DELETE-SELECTION-MODE NIL :LOGICAL-CHARACTERS
#<EQUALP Hash Table{21} 20C3D364> :EXECUTE-MODE #<EDITOR::MODE-OBJECT
"Execute" 20CE37FC> :ECHO-MODE #<EDITOR::MODE-OBJECT "Echo Area"
20CE34A4> :PLIST NIL :INTERRUPT-KEYS (#S(SYSTEM::GESTURE-SPEC :DATA 103
:MODIFIERS 2) #S(SYSTEM::GESTURE-SPEC :DATA 71 :MODIFIERS 2)) :STYLE
:EMACS :POINT-ALWAYS-VISIBLE T :USE-FACE-TO-FULL-WIDTH-P T)

Binding frame:  CAPI::*USE-ACCELERATORS* : T

Binding frame:  CAPI-WIN32-LIB::*ALT-IS-META-KEY* : T

Catch frame: #:CATCHER100675

Call to (SUBFUNCTION MP::PROCESS-SG-FUNCTION MP::INITIALIZE-PROCESS-
STACK) (offset 347)
  MS::IGNORED : :DONT-KNOW

Catch frame: SYSTEM::EXIT-FOREIGN-CALLABLE

 Call to SYSTEM::FOREIGN-CALLABLE-ENTRY-POINT-NEW-PROCESS (offset 133)
     SYSTEM::FUNC : RDNZL::%FOREIGN-CALLABLE/RELEASEDELEGATEADAPTER

Call to SYSTEM::%FUNCALL1-ON-LISP-STACK (offset 34)


SYSTEM::%FUNCALL1-ON-LISP-STACK T



- Dominic Robinson