[Libguestfs] [PATCH nbdkit v2] PROPOSED: server: Implement list_exports.

[Richard W.M. Jones]

Updated proposal, taking into account the default export.  Instead of
adding a second call, I made a couple of changes to list_exports:

(1) If the plugin has a concept of a default export, it should add it
    as the first element in the exports list.

(2) There is a new default_only flag which tells the plugin that the
    client is trying to request the name of the default export, so the
    plugin may return only a single element.  However it's fine for
    plugins to ignore this flag.

What about plugins that don't have any concept of a default export?
This makes the default export be whatever happens to be first in the
list.  Not sure if this is a bad thing or not.

Rich.