From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:45384) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SApiq-0003sD-M4 for qemu-devel@nongnu.org; Thu, 22 Mar 2012 17:39:06 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1SApio-0001OF-RB for qemu-devel@nongnu.org; Thu, 22 Mar 2012 17:39:04 -0400 Received: from mail-gy0-f173.google.com ([209.85.160.173]:62237) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SApio-0001O0-JF for qemu-devel@nongnu.org; Thu, 22 Mar 2012 17:39:02 -0400 Received: by ghrr14 with SMTP id r14so2693352ghr.4 for ; Thu, 22 Mar 2012 14:39:00 -0700 (PDT) Sender: Paolo Bonzini From: Paolo Bonzini Date: Thu, 22 Mar 2012 22:38:40 +0100 Message-Id: <1332452320-21956-1-git-send-email-pbonzini@redhat.com> In-Reply-To: <4F6B9874.4020108@redhat.com> References: <4F6B9874.4020108@redhat.com> Subject: [Qemu-devel] [PATCH v2 06/10] qapi: untangle next_list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: eblake@redhat.com, mdroth@linux.vnet.ibm.com, anthony@codemonkey.ws, lcapitulino@redhat.com Right now, the semantics of next_list are complicated. The caller must: * call start_list * call next_list for each element *including the first* * on the first call to next_list, the second argument should point to NULL and the result is the head of the list. On subsequent calls, the second argument should point to the last node (last result of next_list) and next_list itself tacks the element at the tail of the list. This works for both input and output visitor, but having the visitor write memory when it is only reading the list is ugly. Plus, relying on *list to detect the first call is tricky and undocumented. We can initialize so->entry in next_list instead of start_list, leaving it NULL in start_list. This way next_list sees clearly whether it is on the first call---as a bonus, it discriminates the cases based on internal state of the visitor rather than external state. We can also pull the assignment of the list head from generated code up to next_list. Signed-off-by: Paolo Bonzini --- docs/qapi-code-gen.txt | 4 ++-- qapi/qmp-input-visitor.c | 22 +++++++++++++--------- scripts/qapi-visit.py | 4 ++-- 3 files changed, 17 insertions(+), 13 deletions(-) diff --git a/docs/qapi-code-gen.txt b/docs/qapi-code-gen.txt index 5831e37..ad11767 100644 --- a/docs/qapi-code-gen.txt +++ b/docs/qapi-code-gen.txt @@ -194,11 +194,11 @@ Example: void visit_type_UserDefOneList(Visitor *m, UserDefOneList ** obj, const char *name, Error **errp) { - GenericList *i; + GenericList *i, **prev = (GenericList **)obj; visit_start_list(m, name, errp); - for (i = visit_next_list(m, (GenericList **)obj, errp); i; i = visit_next_list(m, &i, errp)) { + for (; (i = visit_next_list(m, prev, errp)) != NULL; prev = &i) { UserDefOneList *native_i = (UserDefOneList *)i; visit_type_UserDefOne(m, &native_i->value, NULL, errp); } diff --git a/qapi/qmp-input-visitor.c b/qapi/qmp-input-visitor.c index ef9288f..413e333 100644 --- a/qapi/qmp-input-visitor.c +++ b/qapi/qmp-input-visitor.c @@ -64,9 +64,7 @@ static const QObject *qmp_input_get_object(QmpInputVisitor *qiv, static void qmp_input_push(QmpInputVisitor *qiv, const QObject *obj, Error **errp) { qiv->stack[qiv->nb_stack].obj = obj; - if (qobject_type(obj) == QTYPE_QLIST) { - qiv->stack[qiv->nb_stack].entry = qlist_first(qobject_to_qlist(obj)); - } + qiv->stack[qiv->nb_stack].entry = NULL; qiv->nb_stack++; if (qiv->nb_stack >= QIV_STACK_SIZE) { @@ -132,18 +130,24 @@ static GenericList *qmp_input_next_list(Visitor *v, GenericList **list, QmpInputVisitor *qiv = to_qiv(v); GenericList *entry; StackObject *so = &qiv->stack[qiv->nb_stack - 1]; + bool first; + + if (so->entry == NULL) { + so->entry = qlist_first(qobject_to_qlist(so->obj)); + first = true; + } else { + so->entry = qlist_next(so->entry); + first = false; + } if (so->entry == NULL) { return NULL; } entry = g_malloc0(sizeof(*entry)); - if (*list) { - so->entry = qlist_next(so->entry); - if (so->entry == NULL) { - g_free(entry); - return NULL; - } + if (first) { + *list = entry; + } else { (*list)->next = entry; } diff --git a/scripts/qapi-visit.py b/scripts/qapi-visit.py index a85fb76..1ff81f4 100644 --- a/scripts/qapi-visit.py +++ b/scripts/qapi-visit.py @@ -86,14 +86,14 @@ def generate_visit_list(name, members): void visit_type_%(name)sList(Visitor *m, %(name)sList ** obj, const char *name, Error **errp) { - GenericList *i, **head = (GenericList **)obj; + GenericList *i, **prev = (GenericList **)obj; if (error_is_set(errp)) { return; } visit_start_list(m, name, errp); - for (*head = i = visit_next_list(m, head, errp); i; i = visit_next_list(m, &i, errp)) { + for (; (i = visit_next_list(m, prev, errp)) != NULL; prev = &i) { %(name)sList *native_i = (%(name)sList *)i; visit_type_%(name)s(m, &native_i->value, NULL, errp); } -- 1.7.9.1