reversing part of the changes made on 2000/05/17. Doing an explicit
zone shutdown on destruction of the zone table caused the zone to
be shut down prematurely on server reload when the zone table was
destroyed but the zone had already been attached to a new zone table.
An external reference count is needed to correctly handle this situation.
involved extensive restructuring of the reference counting of
zones and related objects.
Zones now attach to their views. To avoid a circular dependency that
would keep views from ever shutting down, this is done using the new
functions dns_view_weakattach() / dns_view_weakdetach() which
guarantee that the view will not be freed but still allow it
to be shut down.
The zones themselves now only have a single reference count, with
similar "weak" semantics. Managed zones must now be shut down
explicitly by calling dns_zone_shutdown(). To shut down all
zones in a zone table, call dns_zt_shutdown().
The zone manager is now reference counted, weakly. To shut down the
zone manager, you must explicitly call dns_zonemgr_shutdown().
Cleanup of redundant/useless header file inclusion.
ISC style lint, primarily for function declarations and standalone
comments -- ie, those that appear on a line without any code, which
should be written as follows:
/*
* This is a comment.
*/
