Re: auth handshake and rendevouz objects

[Niels Möller]

Marcus Brinkmann <address@hidden> writes:

> Well, one question is surely resource allocation.  I think A should provide
> the resource to S that contains the note that B should get a reference to
> the handle.

Hmm. Sounds a little hairy. I think one would really want the
following protocol:

1. A->B:    I'd like to give you the handle (S,x).
2.  B->S:   Gimme handle x. A said I could have it.
3.   S->A:  Do you really want to give x to B?
4.   A->S:  Sure.
5.  S->B:   Ok, here's the handle.
6. B->A:    Thanks, I've got it now.

Except that there's one S->A message, 3, and you say you'd like to
avoid that. I'd be a little surprised if one can come up with an
alternative that avoids both the callback from S to A, and state in S.

You could do S->A by having a separate thread in A that's responsible
for handle transfers, and spends most of it's time in a blocking
receive operation waiting for message 3 (which can arrive from any
server it's talking to). The nice thing about that is that it's A's
responsibility to keep track of transfers that are in progress.

One interesting detail here is that most tasks would need special
bookkeping threads (A for receiving 3, and S for receiving 2), so
these thread id:s must be passed around to all parties that need them.

/Niels