From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:51662) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XUMqs-0002AL-0l for qemu-devel@nongnu.org; Wed, 17 Sep 2014 17:33:34 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XUMqi-00033L-Ub for qemu-devel@nongnu.org; Wed, 17 Sep 2014 17:33:25 -0400 Received: from e8.ny.us.ibm.com ([32.97.182.138]:32825) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XUMqi-000321-Rl for qemu-devel@nongnu.org; Wed, 17 Sep 2014 17:33:16 -0400 Received: from /spool/local by e8.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 17 Sep 2014 17:33:11 -0400 From: Michael Roth Date: Wed, 17 Sep 2014 16:32:54 -0500 Message-Id: <1410989576-9311-3-git-send-email-mdroth@linux.vnet.ibm.com> In-Reply-To: <1410989576-9311-1-git-send-email-mdroth@linux.vnet.ibm.com> References: <1410989576-9311-1-git-send-email-mdroth@linux.vnet.ibm.com> Subject: [Qemu-devel] [PATCH v2 2/4] qapi: dealloc visitor, implement visit_start_union List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: famz@redhat.com, armbru@redhat.com, qemu-stable@nongnu.org, lcapitulino@redhat.com, pbonzini@redhat.com 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 Signed-off-by: Michael Roth --- 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); -- 1.9.1