From patchwork Fri Sep 26 19:04:02 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luiz Capitulino X-Patchwork-Id: 393928 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 91ADA140188 for ; Sat, 27 Sep 2014 05:09:49 +1000 (EST) Received: from localhost ([::1]:51155 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XXatn-0001Bk-0v for incoming@patchwork.ozlabs.org; Fri, 26 Sep 2014 15:09:47 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56033) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XXaoq-0001mr-WF for qemu-devel@nongnu.org; Fri, 26 Sep 2014 15:04:48 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XXaol-0004G5-NN for qemu-devel@nongnu.org; Fri, 26 Sep 2014 15:04:40 -0400 Received: from mx1.redhat.com ([209.132.183.28]:60392) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XXaol-0004EC-Fb for qemu-devel@nongnu.org; Fri, 26 Sep 2014 15:04:35 -0400 Received: from int-mx14.intmail.prod.int.phx2.redhat.com (int-mx14.intmail.prod.int.phx2.redhat.com [10.5.11.27]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id s8QJ4Nbq025027 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Fri, 26 Sep 2014 15:04:23 -0400 Received: from localhost (ovpn-116-58.ams2.redhat.com [10.36.116.58]) by int-mx14.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id s8QJ4L6k013166; Fri, 26 Sep 2014 15:04:22 -0400 From: Luiz Capitulino To: peter.maydell@linaro.org Date: Fri, 26 Sep 2014 15:04:02 -0400 Message-Id: <1411758247-12161-5-git-send-email-lcapitulino@redhat.com> In-Reply-To: <1411758247-12161-1-git-send-email-lcapitulino@redhat.com> References: <1411758247-12161-1-git-send-email-lcapitulino@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.27 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 209.132.183.28 Cc: qemu-devel@nongnu.org, anthony@codemonkey.ws Subject: [Qemu-devel] [PULL 4/9] qapi: dealloc visitor, implement visit_start_union X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org From: Michael Roth If the .data field of a QAPI Union is NULL, we don't need to free any of the union fields. Make use of the new visit_start_union interface to access this information and instruct the generated code to not visit these fields when this occurs. Cc: qemu-stable@nongnu.org Reported-by: Fam Zheng Suggested-by: Paolo Bonzini Reviewed-by: Paolo Bonzini Reviewed-by: Eric Blake Signed-off-by: Michael Roth Signed-off-by: Luiz Capitulino --- qapi/qapi-dealloc-visitor.c | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) diff --git a/qapi/qapi-dealloc-visitor.c b/qapi/qapi-dealloc-visitor.c index dc53545..a14a1c7 100644 --- a/qapi/qapi-dealloc-visitor.c +++ b/qapi/qapi-dealloc-visitor.c @@ -162,6 +162,31 @@ static void qapi_dealloc_type_enum(Visitor *v, int *obj, const char *strings[], { } +/* If there's no data present, the dealloc visitor has nothing to free. + * Thus, indicate to visitor code that the subsequent union fields can + * be skipped. This is not an error condition, since the cleanup of the + * rest of an object can continue unhindered, so leave errp unset in + * these cases. + * + * NOTE: In cases where we're attempting to deallocate an object that + * may have missing fields, the field indicating the union type may + * be missing. In such a case, it's possible we don't have enough + * information to differentiate data_present == false from a case where + * data *is* present but happens to be a scalar with a value of 0. + * This is okay, since in the case of the dealloc visitor there's no + * work that needs to done in either situation. + * + * The current inability in QAPI code to more thoroughly verify a union + * type in such cases will likely need to be addressed if we wish to + * implement this interface for other types of visitors in the future, + * however. + */ +static bool qapi_dealloc_start_union(Visitor *v, bool data_present, + Error **errp) +{ + return data_present; +} + Visitor *qapi_dealloc_get_visitor(QapiDeallocVisitor *v) { return &v->visitor; @@ -191,6 +216,7 @@ QapiDeallocVisitor *qapi_dealloc_visitor_new(void) v->visitor.type_str = qapi_dealloc_type_str; v->visitor.type_number = qapi_dealloc_type_number; v->visitor.type_size = qapi_dealloc_type_size; + v->visitor.start_union = qapi_dealloc_start_union; QTAILQ_INIT(&v->stack);