HPSS: Client-side objects

[Andrew Bennetts]

Robert Collins wrote:
> On Wed, 2007-04-18 at 09:01 -0400, Aaron Bentley wrote:
[...]
> > > 
> > > NULL_REVISION is never stored to disk.
> > 
> > Yes it is.  It is used in the branch 6 format to represent the NULL
> > revision.  When you initialize a branch6 branch, it sets the
> > last-revision to "0 null:\n" 
> 
> Ah, I didn't realise - there used to be a comment saying that
> NULL_REVISION's value is internal only, not to be serialised, and so on.

Although grepping around I see some places use an explicit "null:" rather than
NULL_REVISION.  That isn't really important (it just makes me wonder if there's
some unwritten rules about when the constant should be used rather than the
literal, or just an accident).

Anyway, I've updated the HPSS branch to use "null:" instead of "" to mean
NULL_REVISION on the wire.

-Andrew.