From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.0 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B33AAC07E95 for ; Tue, 20 Jul 2021 00:56:00 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 1D10F6108B for ; Tue, 20 Jul 2021 00:56:00 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1D10F6108B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:46612 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1m5e3D-0007nK-2n for qemu-devel@archiver.kernel.org; Mon, 19 Jul 2021 20:55:59 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:58322) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1m5e26-00076g-0h for qemu-devel@nongnu.org; Mon, 19 Jul 2021 20:54:50 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:26184) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1m5e20-0004iO-6c for qemu-devel@nongnu.org; Mon, 19 Jul 2021 20:54:48 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1626742482; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=jnP+BsQRPwGJ7H4Ux1uHrduoDF3MHnVG15kbrC/vqYo=; b=Wqzd+9rTnhVjc0wH1dQPPGHCopsSVxLgks7OzIGrR3amTycAJz1ycUcikXtck3yiFaTNTG 40GpfIHxeepkcU3GvgfQZ16Z+On/Zk8GZF0XMn+OsNrQT2CR5rxyuRI1GIZxrSPTypauVy E2ztDvrWjFjl2/68PBF1yERMRL5VIhY= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-312-bCN9DrzlOyq-ZKE2kD2rQw-1; Mon, 19 Jul 2021 20:54:38 -0400 X-MC-Unique: bCN9DrzlOyq-ZKE2kD2rQw-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 36A6A10C1ADC for ; Tue, 20 Jul 2021 00:54:38 +0000 (UTC) Received: from redhat.com (ovpn-112-216.phx2.redhat.com [10.3.112.216]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 60A9C60CA0; Tue, 20 Jul 2021 00:54:35 +0000 (UTC) Date: Mon, 19 Jul 2021 19:54:33 -0500 From: Eric Blake To: Paolo Bonzini Subject: Re: [PATCH 1/2] qapi: introduce forwarding visitor Message-ID: <20210720005433.lgroglpa4jk4u4z2@redhat.com> References: <20210719104033.185109-1-pbonzini@redhat.com> <20210719104033.185109-2-pbonzini@redhat.com> MIME-Version: 1.0 In-Reply-To: <20210719104033.185109-2-pbonzini@redhat.com> User-Agent: NeoMutt/20210205 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=eblake@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Received-SPF: pass client-ip=170.10.133.124; envelope-from=eblake@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -42 X-Spam_score: -4.3 X-Spam_bar: ---- X-Spam_report: (-4.3 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1.469, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kwolf@redhat.com, imammedo@redhat.com, alex.williamson@redhat.com, qemu-devel@nongnu.org, armbru@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" 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 > --- > 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 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 -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3266 Virtualization: qemu.org | libvirt.org