[omniORB] CorbaScript on omniORB2

[David Riddoch]

Hi,

> I have started (once again :-() the port of CorbaScript on top of omniORB2.
> I have some comments:
> 
> * Have you plan to implement the Interface Repository?
>   Currently I use the IFR provided by ORBacus and this works.

No plans.  We also use other peoples interface repositories.


> * Why is it not possible to insert a nil object reference into a DynAny?
>   See the following patch:

Good question.  I have no idea why I did this ... so I'll accept your
patch!  Thanks.


>   void
>   DynAnyImpl::insert_reference(CORBA::Object_ptr value)
>   {
>     if ( !CORBA::Object::PR_is_valid(value) )
>       throw CORBA::BAD_PARAM(0,CORBA::COMPLETED_NO);
> 
>   // Merle Philippe
>   //  if( CORBA::is_nil(value) )  throw CORBA::DynAny::InvalidValue();
> 
>     Lock sync(this);
>     CORBA::Object::marshalObjRef(value, doWrite(CORBA::tk_objref));
>   }
> 
>   void
>   DynAnyConstrBase::insert_reference(CORBA::Object_ptr value)
>   {
>     if ( !CORBA::Object::PR_is_valid(value) )
>       throw CORBA::BAD_PARAM(0,CORBA::COMPLETED_NO);
>   
>   // Merle Philippe
>   //  if( CORBA::is_nil(value) )  throw CORBA::DynAny::InvalidValue();
> 
>     Lock sync(this);
>     CORBA::Object::marshalObjRef(value, writeCurrent(CORBA::tk_objref));
>   }
> 
>   void
>   DynUnionImpl::insert_reference(CORBA::Object_ptr value)
>   {
>     if ( !CORBA::Object::PR_is_valid(value) )
>       throw CORBA::BAD_PARAM(0,CORBA::COMPLETED_NO);
> 
>   // Merle Philippe
>   //  if( CORBA::is_nil(value) )  throw CORBA::DynAny::InvalidValue();
> 
>     Lock sync(this);
>     CORBA::Object::marshalObjRef(value, writeCurrent(CORBA::tk_objref));
>     discriminatorHasChanged();
>   }
> 
> 
> * Why is it not possible to create a DynAny with a IDL void type?
>   See the following patch:

Accepted.


>   static DynAnyImplBase*
>   create_dyn_any(TypeCode_base* tc, CORBA::Boolean is_root)
>   {
>     if ( !CORBA::TypeCode::PR_is_valid(tc) )
>       throw CORBA::BAD_PARAM(0,CORBA::COMPLETED_NO);
> 
>     if( CORBA::is_nil(tc) )
>       throw CORBA::BAD_TYPECODE(0, CORBA::COMPLETED_NO);
> 
>     DynAnyImplBase* da = 0;
> 
>     try {
>       switch( tc->NP_kind() ) {
> // ADD Merle Philippe
>       case CORBA::tk_void:
> // END
>       case CORBA::tk_short:
> 
>   CORBA::DynAny_ptr
>   CORBA::ORB::create_basic_dyn_any(TypeCode_ptr tc)
>   {
>     if (!CORBA::TypeCode::PR_is_valid(tc))
>       throw CORBA::BAD_PARAM(0,CORBA::COMPLETED_NO);
> 
>     TypeCode_base* aetc = TypeCode_base::aliasExpand(ToTcBase_Checked(tc));
> 
>     switch( aetc->kind() ) {
> // ADD Merle Philippe
>       case CORBA::tk_void:
> // END
>     case CORBA::tk_short:
> 
> 
> * Is it normal that a subclass of CORBA::BOA::DynamicImplementation
>   must handle "_is_a" CORBA calls into the implementation of the
>   invoke() method?

Our current implementation of the DSI is based loosely on CORBA 2.2, but
was written for a CORBA 2.0 ORB.  In CORBA 2.0 the DSI is not very clearly
specified.  In CORBA 2.2 I think you should handle _is_a() by overriding
ServantBase's version.  However as our version is not built on top of
ServantBase (because we don't yet have a POA) we can't do that.  Thus I
have given the application the opportunity to handle _is_a.  If you
don't want to handle it you are very welcome to throw BAD_OPERATION from
your invoke() routine -- in which case the default version will be used.
I'm not sure that this would be very useful though...

When we have a POA it will use the 'normal' semantics.


> * How can I narrow an object reference to a DynamicImplementation
>subclass instance?
>   I would like to write the following:
> 
>   class MyDSI : public CORBA::BOA::DynamicImplementation {
>   public:
>     ........
>     static MyDSI* _narrow(CORBA::Object_ptr o) { ???? }
>   };

You can't do this, and I personally think it would not be a good idea.
Object references are fundamentally opaque.


>   Why the DynamicImplementation doesn't directly inherit from omniObject and
>   CORBA::Object classes?
>   I have seen that you use a delegation pattern with the internal
>   DsiObject, isn't it?

My way encapsulates the implementation better.  Object implementations
and object references are not the same thing -- so there is no reason why
DynamicImplementation should inherit from CORBA::Object.


> * Here is a report bug:
> 
>   unix> cssh
>   CorbaScript 1.3.1 (Jul 20 1999) for omniORB2 for C++
>   Copyright 1996-99 LIFL, France
>   >>> TestCS.SeqShort
>   < OMG-IDL typedef sequence<short> TestCS::SeqShort; >
>   >>> TestCS.SeqShort(1,2,3,4,5,6)
>   Caught omniORB2 fatalException. This indicates a bug is caught within omniORB2.
>   Please send a bug report.
>   The exception was thrown in file: ../typecode.cc
>                               line: 949
>   The error message is: TypeCode_base::NP_aliasExpand() - should not
> have been called
>   unix>
> 
>   I have this report several times in my demonstration.

Could you try and get me a stack trace, or give me a minimal example?


> Even with these problems (and corrections), CorbaScript begins to work
> on top of omniORB2:-)

Excellent.  Let us know when it is ready for others to use, and I'll put a
link up on our site.


Cheers,
David