valuebase.cpp

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// ValueBase.cpp,v 1.7 2003/12/28 16:33:05 bala Exp

#include "ValueBase.h"
#include "ValueFactory.h"

#include "tao/ORB.h"
#include "tao/ORB_Core.h"
#include "tao/debug.h"
#include "tao/Typecode.h"

#if !defined (__ACE_INLINE__)
# include "ValueBase.inl"
#endif /* ! __ACE_INLINE__ */

ACE_RCSID (tao,
           ValueBase,
           "ValueBase.cpp,v 1.7 2003/12/28 16:33:05 bala Exp")




// Static operations in namespace CORBA.

void
CORBA::add_ref (CORBA::ValueBase *val)
{
  if (val)
    {
      val->_add_ref ();
    }
}

void
CORBA::remove_ref (CORBA::ValueBase *val)
{
  if (val)
    {
      val->_remove_ref ();
    }
}

// ***********************************************************************

CORBA::ValueBase::ValueBase (void)
{
}

CORBA::ValueBase::ValueBase (const ValueBase&)
{
}

CORBA::ValueBase::~ValueBase (void)
{
}

CORBA::ValueBase*
CORBA::ValueBase::_downcast (CORBA::ValueBase *vt)
{
  // Every vt is a CORBA::ValueBase :-).
  return vt;
}

void
CORBA::ValueBase::_tao_any_destructor (void *x)
{
  CORBA::ValueBase *tmp = ACE_static_cast (CORBA::ValueBase *, x);
  CORBA::remove_ref (tmp);
}

// OBV marshaling in principle:
// _tao_marshal () is called from the CDR operator<< ()
// to marshal a valuetype. To marshal the state
// it calls (virtual) _tao_marshal_v () (IDL generated) on itself
// which 'jumps' to the most derived valuetype class. This function
// further calls (inline) _tao_marshal_state, which is generated from
// IDL too and does the marshaling of state members and base classes
// (before, if any) actually.
// Fragmentation (chunking) needs some cooperation with the CDR stream.
// It needs to keep track of the state we're in:
// (outside chunk, beginning of chunk - no data, inside chunk and
// the nesting level of valuetypes. (The chunks itself are not nested.))

// (see CORBA 2.3 GIOP 15.3.4)

CORBA::Boolean
CORBA::ValueBase::_tao_marshal (TAO_OutputCDR &strm,
                                CORBA::ValueBase *this_,
                                ptrdiff_t /* formal_type_id */)
{
  CORBA::Boolean retval = 1;
  // %! yet much to do ... look for +++ !

  // 1. Is 'this' yet marshalled ? (->1a)
  //    If not then mark 'this' as marshalled. (->2) +++
  //    Or is it null ? (write null_ref and return ok)
  // 1a. Put indirection and return successfull.

  if (this_ == 0)
    {
      retval = strm.write_ulong (0);
      // write TAO_OBV_GIOP_Flags::Null_ref
      return retval;
    }

  // 2. if (chunking) and we are in a chunk (look in strm),
  //    end the chunk by writing its length at its start.
  //    This is the responsibility of the CDR stream. +++
  //    But if nothing is writtern in this chunk yet,
  //    we want to overwrite the place of the dummy blocksize-tag
  //    with our <value-tag>.
  //    Increase the nesting level of valuetypes.

  // 3. Build <value-tag>, which states if chunking is used
  //    and if type information ((list of) repository id(s))
  //    is provided. The latter is necessary if the formal_type_id
  //    is unequal the 'true derived' type of this object. +++

  CORBA::ULong value_tag = TAO_OBV_GIOP_Flags::Value_tag_base
                           | TAO_OBV_GIOP_Flags::Type_info_single;

  retval = strm.write_ulong (value_tag);

  if (! retval)
    {
      return retval;
    }

  // 4. Marshal type information.

  retval = strm.write_string (this_->_tao_obv_repository_id ());

  if (! retval)
    {
      return retval;
    }

  // 5. if (chunking) let room for a blocksize-tag. (i.e. write ULong)

  // 6. Now marshal state members. (%! Problem when state is empty
  //    and chunked encoding is used.)

  retval = this_->_tao_marshal_v (strm);

  // 7. if (chunking) let strm overwrite the last blocksize tag
  //    with its concrete value.                                 +++
  // 8. if (chunking) write an end tag, or (optimization) let the CDR
  //    care for collecting all end tags of nested values (e.g. linked
  //    list), so that only one end tag at all must be written.  +++

  return retval;
}


CORBA::Boolean
CORBA::ValueBase::_tao_unmarshal (TAO_InputCDR &strm,
                                  CORBA::ValueBase *&new_object)
{
  // This is for the special case only that one unmarshals in order
  // to assign the newly created object directly to a ValueBase pointer.
  // Implementation is like a specialized one (in TC.cpp, if T.idl is source).
  // basically do:
  //  ValueBase::_tao_unmarshal_pre ()
  //    (Gets factory or possible a null or an existing object.
  //     Then the job is done. On an existing (backreferenced) object
  //     do a cast and a type check)
  //  new_object = factory->create_for_unmarshal ()
  //     (with apropriate cast)
  //  new_object->_tao_unmarshal_v ()
  //  new_object->_tao_unmarshal_post ()

//  CORBA::ValueBase *base = 0;
  CORBA::ValueFactory_var factory;
  CORBA::Boolean retval =
    CORBA::ValueBase::_tao_unmarshal_pre (strm,
                                          factory.out (),
                                          new_object,
                                          0);

  if (retval == 0)
    {
      return 0;
    }

  if (factory.in () != 0)
    {
      new_object = factory->create_for_unmarshal ();

      if (new_object == 0)
        {
          return 0;  // %! except.?
        }

      retval = new_object->_tao_unmarshal_v (strm);

      if (retval == 0)
        {
          return 0;
        }
    }

  // Now base must be null or point to the unmarshaled object.
  // Align the pointer to the right subobject.
//  new_object = CORBA::ValueBase::_downcast (base);
  return retval;
}


CORBA::Boolean
CORBA::ValueBase::_tao_unmarshal_pre (TAO_InputCDR &strm,
                                      CORBA::ValueFactory &factory,
                                      CORBA::ValueBase *&valuetype,
                                      const char * const repo_id)
{ // %! dont leak on error case !
  // %! postconditions
  CORBA::Boolean retval = 1;
  factory = 0;
  // %! yet much to do ... look for +++ !

  // 1. Get the <value-tag> (else it may be <indirection-tag> or <null-ref>).
  //    Is object yet unmarshalled (<indirection-tag> is set) ? (->1a)
  //    Is <null-ref> given ? Set 0 and return ok.
  // 1a. Lookup the real address in memory, which should be aligned +++
  //     to CORBA::ValueBase. Its possible at this point that worse
  //     type mismatch gets by undetected, if the CDR stream fakes.
  //     So the type should be checked ... +++

  CORBA::ULong value_tag;

  if (!strm.read_ulong (value_tag))
    {
      return 0;
    }

  if (TAO_OBV_GIOP_Flags::is_null_ref (value_tag))
    {
      valuetype = 0;
      return 1;
      // ok, null reference unmarshaled
    }
  // 2. Now at this point it must be a <value-tag> (error else).
  //    if (chunking) check that any last chunk ends with matching
  //    size. If not raise marshal exception.
  //    Increase the nesting level of valuetypes.

  if (!TAO_OBV_GIOP_Flags::is_value_tag (value_tag))
    {
      ACE_DEBUG ((LM_DEBUG,
                  ACE_TEXT ("!CORBA::ValueBase::_tao_unmarshal_pre ")
                  ACE_TEXT ("not value_tag\n")));
      return 0;
    }

  // 3. if (chunking) read and record the blocksize-tag.

  // 4. Unmarshal type information and lookup factory.
  //    If no type information is given in the CDR encoding, as told
  //    from the <value-tag>, then use the repository id parameter
  //    (it _must_ be right).

  TAO_ORB_Core *orb_core = strm.orb_core ();

  if (orb_core == 0)
    {
      orb_core = TAO_ORB_Core_instance ();

      if (TAO_debug_level > 0)
        {
          ACE_DEBUG ((LM_WARNING,
                      "TAO (%P|%t) WARNING: extracting valuetype using "
                      "default ORB_Core\n"));
        }
    }

  if (TAO_OBV_GIOP_Flags::has_no_type_info (value_tag))
  {
     factory = orb_core->orb ()->lookup_value_factory (repo_id);