On 01/20/2016 11:49 AM, Markus Armbruster wrote:
> Eric Blake <ebl...@redhat.com> writes:
>
>> Similar to the previous patch, it's nice to have all functions
>> in the tree that involve a visitor and a name for conversion to
>> or from QAPI to consistently stick the 'name' parameter next
>> to the Visitor parameter.
>>
>> Done by manually changing include/qom/object.h and qom/object.c,
>> then running this Coccinelle script and touching up the fallout
>> (Coccinelle insisted on adding some trailing whitespace).
>>
>> @ rule1 @
>> identifier fn;
>> type Object, Visitor, Error;
>> identifier obj, v, opaque, name, errp;
>> @@
>> void fn
>> - (Object *obj, Visitor *v, void *opaque, const char *name,
>> + (Object *obj, Visitor *v, const char *name, void *opaque,
>> Error **errp) { ... }
>
> I think we want to match void functions with exactly these parameter
> types. The parameter names don't matter.
The parameter names shouldn't matter; the 'identifier obj' should have
been enough to make 'obj' a metavariable matching any actual parameter name.
>
> However, the actual match is looser! For instance, it also matches
>
> void foo(int *pi, unsigned *pu, void *vp, const char *cp, double **dpp)
> {
> }
Uggh. My intent was to match exactly 'Object *' and 'Visitor *' as the
first two types, where 'int *' and 'unsigned *' are NOT matches. But I
don't know Coccinelle well enough to make that blatantly obvious (is my
declaration of 'type Object' not correct?).
>
> This could mess up unrelated function. I could double-check it doesn't,
> but I'd rather have a narrower match instead. Can't give one offhand,
> though. Ideas?
Is 'typedef' better than 'type' for constraining the type of the first
two arguments? Or does Coccinelle do literal matches on anything you
don't pre-declare, as in:
@ rule1 @
identifier fn;
identifier obj, v, opaque, name, errp;
@@
void fn
- (Object *obj, Visitor *v, void *opaque, const char *name,
+ (Object *obj, Visitor *v, const char *name, void *opaque,
Error **errp) { ... }
Fortunately, a manual inspection of the results (which I had to do
anyways due to spacing issues) didn't spot any incorrect swaps.
At this point, I don't know that re-writing Coccinelle will be worth the
hassle (nothing else needs to be rewritten).
>
>>
>> @@
>> identifier rule1.fn;
>> expression obj, v, opaque, name, errp;
>> @@
>> fn(obj, v,
>> - opaque, name,
>> + name, opaque,
>> errp)
>
> The rule1.fn restricts the match to functions changed by the previous
> rule. Good.
>
>>
>> Signed-off-by: Eric Blake <ebl...@redhat.com>
>> Reviewed-by: Marc-André Lureau <marcandre.lur...@redhat.com>
>
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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