[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [PATCH 1/2] qapi: introduce forwarding visitor
From: |
Eric Blake |
Subject: |
Re: [PATCH 1/2] qapi: introduce forwarding visitor |
Date: |
Mon, 19 Jul 2021 19:54:33 -0500 |
User-agent: |
NeoMutt/20210205 |
On Mon, Jul 19, 2021 at 12:40:32PM +0200, Paolo Bonzini wrote:
> This new adaptor visitor takes a single field of the adaptee, and exposes it
> with a different name.
>
> This will be used for QOM alias properties. Alias targets can of course
> have a different name than the alias property itself (e.g. a machine's
> pflash0 might be an alias of a property named 'drive'). When the target's
> getter or setter invokes the visitor, it will use a different name than
> what the caller expects, and the visitor will not be able to find it
> (or will consume erroneously).
How does this differ from Kevin's attempt to add QMP aliasing,
https://lists.gnu.org/archive/html/qemu-devel/2021-02/msg04097.html
>
> The solution is for alias getters and setters to wrap the incoming
> visitor, and forward the sole field that the target is expecting while
> renaming it appropriately.
>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
> diff --git a/include/qapi/forward-visitor.h b/include/qapi/forward-visitor.h
> new file mode 100644
> index 0000000000..c7002d53e6
> --- /dev/null
> +++ b/include/qapi/forward-visitor.h
> +
> +typedef struct ForwardFieldVisitor ForwardFieldVisitor;
> +
> +/*
> + * The forwarding visitor only expects a single name, @from, to be passed for
> + * toplevel fields. It is converted to @to and forward to the @target
> visitor.
and forwarded
> + * Calls within a struct are forwarded without changing the name.
> + */
> +Visitor *visitor_forward_field(Visitor *target, const char *from, const char
> *to);
> +
> +#endif
> +++ b/qapi/qapi-forward-visitor.c
> @@ -0,0 +1,307 @@
> +/*
> + * Forward Visitor
> + *
> + * Copyright (C) 2021 Red Hat, Inc.
> + *
> + * This work is licensed under the terms of the GNU LGPL, version 2.1 or
> later.
> + * See the COPYING.LIB file in the top-level directory.
> + *
> + */
> +
> +#include "qemu/osdep.h"
> +#include <math.h>
Did you really use math.h?
> +
> +static void forward_field_complete(Visitor *v, void *opaque)
> +{
> + /*
> + * Do nothing, the complete method will be called at due time
s/at/in/
> + * on the target visitor.
> + */
> +}
> +
> +++ b/tests/unit/test-forward-visitor.c
> @@ -0,0 +1,165 @@
> +/*
> + * QAPI Forwarding Visitor unit-tests.
Otherwise it looks like it does what it advertises. I don't know if
Markus will have any opinions, but I'm comfortable with:
Reviewed-by: Eric Blake <eblake@redhat.com>
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3266
Virtualization: qemu.org | libvirt.org
[PATCH 2/2] qom: use correct field name when getting/setting alias properties, Paolo Bonzini, 2021/07/19
Re: [PATCH 0/2] qapi/qom: use correct field name when getting/setting alias properties, Markus Armbruster, 2021/07/20