RE: "any within struct" ORBit decoding problem

["Pete Kingswell" <pete anvil co uk>]

Hi,
building on Philip et al's discovery about the ordering of the struct's
contents, a colleague of mine delved into src/orb/orbit_typecode.c and found
that, in his words, "the bug was to do with alignment of the read pointer to
a 4 byte boundary
before reading the typecode information."

With the fix in place, our patched orbit orb was able to demarshal complex
nested structs with anys in that it had previously bombed out on.  The
commented line in the code extract below identifies the fix in
src/orb/orbit_typecode.c:


void ORBit_decode_CORBA_TypeCode(CORBA_TypeCode* t, GIOPRecvBuffer* buf)
{
        CDR_Codec codec_d;
	CDR_Codec* codec = &codec_d;
	TCDecodeContext ctx;
	GSList* l;

	CDR_codec_init_static(codec);

	/* Need to realign to 4 byte boundary before attempting to decode the
typecode */
 	buf->cur = ALIGN_ADDRESS(buf->cur, 4);

	codec->buffer=buf->cur;
	codec->release_buffer=CORBA_FALSE;
	codec->readonly=CORBA_TRUE;


This was tested on a setup that has ACE/TAO servers with perl clients.  I'm
using ORBit 0.5.7, perl 5.005_03, CORBA::ORBit 0.4.3 and TAO 1.1.10 on
RedHat Linux 2.2.14-6.1.1smp.

Thanks,
peter.

Pete Kingswell
Developer
Anvil Software
+44 207 7497943


-----Original Message-----
From: orbit-list-admin@gnome.org [mailto:orbit-list-admin@gnome.org]On
Behalf Of Philip Lijnzaad
Sent: 12 June 2001 17:54
To: lijnzaad@ebi.ac.uk
Cc: orbit-list@gnome.org; senger@ebi.ac.uk
Subject: Re: "any within struct" ORBit decoding problem



On Tue, 12 Jun 2001 11:35:07 +0100,
"me" == Philip Lijnzaad <lijnzaad@ebi.ac.uk> wrote:

me> This has been a while ago, so I include the whole mail. The question is,
has
me> anything changed in the mean time? We have a very similar setup, and are
me> trying to send a

me>     struct Property {
me> 	string property_name;
me> 	any property_value;
me>     };

me> to a Java server (using ORBacus 4.0.5). Plain anys (i.e. not as part of
a
me> struct) appear to work fine, both as clients/servers and
sending/receiving.
me> However anys as part of a struct just don't get marshalled (although we
don't
me> get a failed assertion).

me> I haven't seen a follow-up to this mail; has this (IMHO serious) problem
been
me> solved in the mean time? Should I get the latest ORBit snapshot from CVS
?

me> 'any' help appreciated !-)
me>
Philip

OK, some more info. It turns out that it's more an interoperability problem.
To quote from a mail by my colleague Martin Senger, who investigated this in
some detail:

  1) All examples work fine when both server and client are orbit-perl. That
  means we have here an interoperability problem.

  2) Standalone Anys work also fine. For example, method:
     any get_any (in any my_any)

  3) The problems are when an Any is a member of a struct. Such Any is not
  passed throught the wire at all (in any combinantion of perl-orbit and
  java servers/clients). Or it is lost during un/marshalling - I do not know
  where.
     Interesting - especially for the orbit-perl developers - is that the
  Any in struct works if it is the first member of the struct. So, passing
  this:

    struct MyStructure {
      any    value;
      string name;
    };

  works, but passing this:

    struct MyStructure {
      string name;
      any    value;
    };

  does not work.

  4) When I am passing an array of Anys:
     - again it works for orbit-perl on both sides,
     - surprisingly itworks for the combinantion client-in-orbit-perl and
  server in java-orbacus (which gives me some chnaces to continue with the
  'novella' project, at least until the bug is fixed)
      - and it does not work for client-in-java and server-in-orbit-perl
  (actually it works only for the first element of the array but not for the
  rest - sic!).

  5) Sending/receiving array of structs with an Any as a member also does
  not work (and again it works for the first struct but not for the others).
  Just to be sure, I also checked sending/receiving array of structs without
  any Any as members - and it works fine. So the problem is with Anys not
  with sending arrays of structs.

I have tried to see if a plain C orbit-client could pass structs with
any-members to and from an ORBacus server, but I have failed so far (which
due to the scarcity of documentation on anys in C; see also my mail to
news:comp.object.corba).

The complete examples are available from

  ftp://ftp.ebi.ac.uk/pub/lijnzaad/novella-tests.tar.gz

PS: following plea still stands :-)

me> PS: I have so failed to find any examples on how to work with anys in
ORBit;
me>     any pointers (sorry about the pun again) would be very welcome.


--
If you have a procedure with 10 parameters, you probably missed some.
(Kraulis)
----------------------------------------------------------------------------
-
Philip Lijnzaad, lijnzaad@ebi.ac.uk \ European Bioinformatics Institute,rm
A2-08
+44 (0)1223 49 4639                 / Wellcome Trust Genome Campus, Hinxton
+44 (0)1223 49 4468 (fax)           \ Cambridgeshire CB10 1SD,  GREAT
BRITAIN


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