Re: [Qemu-devel] [PATCH RFC v2 38/47] qapi-commands: De-duplicate output marshaling functions

[Eric Blake]

On 07/01/2015 02:22 PM, Markus Armbruster wrote:
> gen_marshal_output() uses its parameter name only for name of the
> generated function.  Name it after the type being marshaled instead of
> its caller, and drop duplicates.
> 
> Saves 7 copies of qmp_marshal_output_int() in qemu-ga, and one copy of
> qmp_marshal_output_str() in qemu-system-*.

 qga/qapi-generated/qga-qmp-marshal.c |  227
+++++------------------------------
 qmp-marshal.c                        |  225
+++++++++++++++-------------------
 2 files changed, 134 insertions(+), 318 deletions(-)

Most changes look like:

-static void qmp_marshal_output_add_fd(AddfdInfo *ret_in, QObject
**ret_out, Error **errp)
+static void qmp_marshal_output_AddfdInfo(AddfdInfo *ret_in, QObject
**ret_out, Error **errp)
 {
     Error *local_err = NULL;
     QmpOutputVisitor *mo = qmp_output_visitor_new();
@@ -88,7 +88,7 @@ void qmp_marshal_add_fd(QDict *args, QOb
         goto out;
     }

-    qmp_marshal_output_add_fd(retval, ret, &local_err);
+    qmp_marshal_output_AddfdInfo(retval, ret, &local_err);

coupled with wholesale deletions of functions that previously had
identical bodies.  Nice.

[I suspect there might be ways to trim a LOT more code size, by
rewriting a generic marshaller helper that is passed a varargs or
array-of-struct list of operations to perform in order to visit an
arbitrary object, then having each command's marshaller generated with
the appropriate list of arguments for the generic helpers rather than
the current approach of calling out to one marshaller helper per type -
but exploring ideas like that is work for another series]

> 
> Signed-off-by: Markus Armbruster <address@hidden>
> ---
>  scripts/qapi-commands.py | 16 +++++++++-------
>  1 file changed, 9 insertions(+), 7 deletions(-)

Reviewed-by: Eric Blake <address@hidden>

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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