CORBA3 — TypeCodes for custom marshaled valuetypes

It is underspecified what value member information for custom
marshaled valuetypes an ORB must provide.

Users of custom marshaled valuetypes must provide their own marshaling
code, and the ORB has no way of knowing what it does before executing
it.

This comes into play for custom marshaled valuetypes inside of Anys,
as well as the ValueMemberSeq in the FullValueDescription of a custom
marshaled valuetype.

In both cases, one can query whether or not the valuetype is custom
marshaled. With Anys, the TypeCode has a ValueModifier type_modifier
which is set to VM_CUSTOM. The FullValueDescription includes a
boolean is_custom.

I can see two possible solutions:

1. TypeCodes for custom marshaled valuetypes will encode no value
member information, so the member_count will be 0. The
FullValueDescription will have a zero length sequence for the
ValueMemberSeq members.

or

2. Value member information for the TypeCode or FullValueDescription
for a custom marshaled valuetype is the state defined in the
valuetype's IDL in the same way as if it were not custom marshaled.

I propose #1 as the solution. This member information is only useful
for finding out what is encoded, and solution #2 doesn't provide
that. Plus, it can be very expensive to create and transmit if many
repository IDs are involved.

see above