• Eric Blake's avatar
    qobject: Simplify QObject · 55e1819c
    Eric Blake authored
    The QObject hierarchy is small enough, and unlikely to grow further
    (since we only use it to map to JSON and already cover all JSON
    types), that we can simplify things by not tracking a separate
    vtable, but just inline the code element of the vtable QType
    directly into QObject (renamed to type), and track a separate array
    of destroy functions.  We can drop qnull_destroy_obj() in the
    process.
    
    The remaining QObject subclasses must export their destructor.
    
    This also has the nice benefit of moving the typename 'QType'
    out of the way, so that the next patch can repurpose it for a
    nicer name for 'qtype_code'.
    
    The various objects are still the same size (so no change in cache
    line pressure), but now have less indirection (although I didn't
    bother benchmarking to see if there is a noticeable speedup, as
    we don't have hard evidence that this was in a performance hotspot
    in the first place).
    
    A future patch could drop the refcnt size to 32 bits for a smaller
    struct on 64-bit architectures, if desired (we have limits on the
    largest JSON that we are willing to parse, and will probably never
    need to take full advantage of a 64-bit refcnt).
    Suggested-by: 's avatarMarkus Armbruster <armbru@redhat.com>
    Signed-off-by: 's avatarEric Blake <eblake@redhat.com>
    Message-Id: <1449033659-25497-2-git-send-email-eblake@redhat.com>
    Signed-off-by: 's avatarMarkus Armbruster <armbru@redhat.com>
    55e1819c
Makefile.objs 146 Bytes