From bug #30296 comment 21:
"I can't help feeling that gabble_parse_xmpp_uri() should validate the node,
domain and resource individually - at the moment it does a *lot* of JID ->
tuple -> JID -> tuple round-trips - but to do that properly, we'd need Wocky to
expose wocky_validate_jid_node(), wocky_validate_jid_domain(), and a new
wocky_validate_jid_domain() (at the moment the first two are static and the
third is just "is a non-empty string")."