[OLE #94] Correctly marshal NULL ppUnk refptrs in NdrPointerMarshall

[Mike Hearn]

On Mon, 2005-06-06 at 10:26 -0500, Robert Shearman wrote:
> >   switch (type) {
> >-  case RPC_FC_RP: /* ref pointer (always non-null) */
> >-#if 0 /* this causes problems for InstallShield so is disabled - we
> need more tests */
> >-    if (!Pointer)
> >-      RpcRaiseException(RPC_X_NULL_REF_POINTER);
> >-#endif
> >+  case RPC_FC_RP: /* ref pointer (always non-null but may point to
> null) */
> >     break;
> >   case RPC_FC_UP: /* unique pointer */
> >   case RPC_FC_OP: /* object pointer - same as unique here */
> >
> >  
> >
> 
> This looks wrong. A ref pointer shouldn't be treated as a unique
> pointer in any circumstances AFAIK. I'll add this case to my mini test
> suite to confirm or deny this hypothesis.

This is wire-sizing, the full code is:

  switch (type) {
  case RPC_FC_RP:
  case RPC_FC_OP:
  case RPC_FC_UP:
    pStubMsg->BufferLength += 4;
    /* NULL pointer has no further representation */
    if (!Pointer)
        return;
    break;
  case RPC_FC_FP:
  default:
    FIXME("unhandled ptr type=%02x\n", type);
    RpcRaiseException(RPC_X_BAD_STUB_DATA);
  }

  m = NdrBufferSizer[*desc & NDR_TABLE_MASK];
  if (m) m(pStubMsg, Pointer, desc);
  else FIXME("no buffersizer for data type=%02x\n", *desc);

In this case, we need to reserve space for a refptr on the wire to be
able to tell the difference between NULL and non-NULL. So it reserves 4
bytes in the buffer.