qemu/include/qapi
Eric Blake 55e1819c50 qobject: Simplify QObject
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: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1449033659-25497-2-git-send-email-eblake@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
2015-12-17 08:21:28 +01:00
..
qmp qobject: Simplify QObject 2015-12-17 08:21:28 +01:00
dealloc-visitor.h qapi: move include files to include/qobject/ 2012-12-19 08:31:31 +01:00
error.h qapi: Change munging of CamelCase enum values 2015-12-17 08:21:28 +01:00
opts-visitor.h OptsVisitor: don't try to flatten overlong integer ranges 2013-08-20 11:52:00 -04:00
qmp-event.h qapi: add event helper functions 2014-06-23 11:01:25 -04:00
qmp-input-visitor.h qapi: move include files to include/qobject/ 2012-12-19 08:31:31 +01:00
qmp-output-visitor.h qapi: move include files to include/qobject/ 2012-12-19 08:31:31 +01:00
string-input-visitor.h qapi: move include files to include/qobject/ 2012-12-19 08:31:31 +01:00
string-output-visitor.h qapi: Add human mode to StringOutputVisitor 2014-02-14 21:12:03 +01:00
util.h qom: Make enum string tables const-correct 2015-06-19 18:42:18 +02:00
visitor-impl.h qapi: Introduce a first class 'any' type 2015-09-21 09:56:49 +02:00
visitor.h qapi: Remove dead visitor code 2015-12-17 08:21:27 +01:00