qapi: Split visit_end_struct() into pieces
As mentioned in previous patches, we want to call visit_end_struct()
functions unconditionally, so that visitors can release resources
tied up since the matching visit_start_struct() without also having
to worry about error priority if more than one error occurs.
Even though error_propagate() can be safely used to ignore a second
error during cleanup caused by a first error, it is simpler if the
cleanup cannot set an error. So, split out the error checking
portion (basically, input visitors checking for unvisited keys) into
a new function visit_check_struct(), which can be safely skipped if
any earlier errors are encountered, and leave the cleanup portion
(which never fails, but must be called unconditionally if
visit_start_struct() succeeded) in visit_end_struct().
Generated code in qapi-visit.c has diffs resembling:
|@@ -59,10 +59,12 @@ void visit_type_ACPIOSTInfo(Visitor *v,
| goto out_obj;
| }
| visit_type_ACPIOSTInfo_members(v, obj, &err);
|- error_propagate(errp, err);
|- err = NULL;
|+ if (err) {
|+ goto out_obj;
|+ }
|+ visit_check_struct(v, &err);
| out_obj:
|- visit_end_struct(v, &err);
|+ visit_end_struct(v);
| out:
and in qapi-event.c:
@@ -47,7 +47,10 @@ void qapi_event_send_acpi_device_ost(ACP
| goto out;
| }
| visit_type_q_obj_ACPI_DEVICE_OST_arg_members(v, ¶m, &err);
|- visit_end_struct(v, err ? NULL : &err);
|+ if (!err) {
|+ visit_check_struct(v, &err);
|+ }
|+ visit_end_struct(v);
| if (err) {
| goto out;
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1461879932-9020-20-git-send-email-eblake@redhat.com>
[Conflict with a doc fixup resolved]
Signed-off-by: Markus Armbruster <armbru@redhat.com>
diff --git a/block/crypto.c b/block/crypto.c
index 1903e84..2424a4c 100644
--- a/block/crypto.c
+++ b/block/crypto.c
@@ -196,7 +196,6 @@
OptsVisitor *ov;
QCryptoBlockOpenOptions *ret = NULL;
Error *local_err = NULL;
- Error *end_err = NULL;
ret = g_new0(QCryptoBlockOpenOptions, 1);
ret->format = format;
@@ -219,9 +218,11 @@
error_setg(&local_err, "Unsupported block format %d", format);
break;
}
+ if (!local_err) {
+ visit_check_struct(opts_get_visitor(ov), &local_err);
+ }
- visit_end_struct(opts_get_visitor(ov), &end_err);
- error_propagate(&local_err, end_err);
+ visit_end_struct(opts_get_visitor(ov));
out:
if (local_err) {
@@ -242,7 +243,6 @@
OptsVisitor *ov;
QCryptoBlockCreateOptions *ret = NULL;
Error *local_err = NULL;
- Error *end_err = NULL;
ret = g_new0(QCryptoBlockCreateOptions, 1);
ret->format = format;
@@ -265,9 +265,11 @@
error_setg(&local_err, "Unsupported block format %d", format);
break;
}
+ if (!local_err) {
+ visit_check_struct(opts_get_visitor(ov), &local_err);
+ }
- visit_end_struct(opts_get_visitor(ov), &end_err);
- error_propagate(&local_err, end_err);
+ visit_end_struct(opts_get_visitor(ov));
out:
if (local_err) {
diff --git a/docs/qapi-code-gen.txt b/docs/qapi-code-gen.txt
index b4ae1be..d135847 100644
--- a/docs/qapi-code-gen.txt
+++ b/docs/qapi-code-gen.txt
@@ -899,10 +899,12 @@
goto out_obj;
}
visit_type_UserDefOne_members(v, *obj, &err);
- error_propagate(errp, err);
- err = NULL;
+ if (err) {
+ goto out_obj;
+ }
+ visit_check_struct(v, &err);
out_obj:
- visit_end_struct(v, &err);
+ visit_end_struct(v);
out:
error_propagate(errp, err);
}
@@ -1007,7 +1009,10 @@
goto out;
}
visit_type_UserDefOneList(v, "arg1", &arg1, &err);
- visit_end_struct(v, err ? NULL : &err);
+ if (!err) {
+ visit_check_struct(v, &err);
+ }
+ visit_end_struct(v);
if (err) {
goto out;
}
@@ -1026,7 +1031,7 @@
v = qapi_dealloc_get_visitor(qdv);
visit_start_struct(v, NULL, NULL, 0, NULL);
visit_type_UserDefOneList(v, "arg1", &arg1, NULL);
- visit_end_struct(v, NULL);
+ visit_end_struct(v);
qapi_dealloc_visitor_cleanup(qdv);
}
diff --git a/hw/ppc/spapr_drc.c b/hw/ppc/spapr_drc.c
index 480a8c6..e3a6191 100644
--- a/hw/ppc/spapr_drc.c
+++ b/hw/ppc/spapr_drc.c
@@ -297,7 +297,8 @@
case FDT_END_NODE:
/* shouldn't ever see an FDT_END_NODE before FDT_BEGIN_NODE */
g_assert(fdt_depth > 0);
- visit_end_struct(v, &err);
+ visit_check_struct(v, &err);
+ visit_end_struct(v);
if (err) {
error_propagate(errp, err);
return;
diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c
index 9dbe681..8c15e09 100644
--- a/hw/virtio/virtio-balloon.c
+++ b/hw/virtio/virtio-balloon.c
@@ -138,17 +138,18 @@
for (i = 0; i < VIRTIO_BALLOON_S_NR; i++) {
visit_type_uint64(v, balloon_stat_names[i], &s->stats[i], &err);
if (err) {
- break;
+ goto out_nested;
}
}
- error_propagate(errp, err);
- err = NULL;
- visit_end_struct(v, &err);
+ visit_check_struct(v, &err);
+out_nested:
+ visit_end_struct(v);
+ if (!err) {
+ visit_check_struct(v, &err);
+ }
out_end:
- error_propagate(errp, err);
- err = NULL;
- visit_end_struct(v, &err);
+ visit_end_struct(v);
out:
error_propagate(errp, err);
}
diff --git a/include/qapi/visitor-impl.h b/include/qapi/visitor-impl.h
index 88d27d5..b20a922 100644
--- a/include/qapi/visitor-impl.h
+++ b/include/qapi/visitor-impl.h
@@ -43,8 +43,11 @@
void (*start_struct)(Visitor *v, const char *name, void **obj,
size_t size, Error **errp);
+ /* Optional; intended for input visitors */
+ void (*check_struct)(Visitor *v, Error **errp);
+
/* Must be set to visit structs */
- void (*end_struct)(Visitor *v, Error **errp);
+ void (*end_struct)(Visitor *v);
/* Must be set */
void (*start_list)(Visitor *v, const char *name, Error **errp);
diff --git a/include/qapi/visitor.h b/include/qapi/visitor.h
index 709cca0..fe268fe 100644
--- a/include/qapi/visitor.h
+++ b/include/qapi/visitor.h
@@ -192,10 +192,11 @@
* }
* outlist:
* visit_end_list(v);
+ * if (!err) {
+ * visit_check_struct(v, &err);
+ * }
* outobj:
- * error_propagate(errp, err);
- * err = NULL;
- * visit_end_struct(v, &err);
+ * visit_end_struct(v);
* out:
* error_propagate(errp, err);
* ...clean up v...
@@ -249,17 +250,27 @@
size_t size, Error **errp);
/*
- * Complete an object visit started earlier.
+ * Prepare for completing an object visit.
*
* @errp obeys typical error usage, and reports failures such as
* unparsed keys remaining in the input stream.
*
+ * Should be called prior to visit_end_struct() if all other
+ * intermediate visit steps were successful, to allow the visitor one
+ * last chance to report errors. May be skipped on a cleanup path,
+ * where there is no need to check for further errors.
+ */
+void visit_check_struct(Visitor *v, Error **errp);
+
+/*
+ * Complete an object visit started earlier.
+ *
* Must be called after any successful use of visit_start_struct(),
* even if intermediate processing was skipped due to errors, to allow
* the backend to release any resources. Destroying the visitor early
* behaves as if this was implicitly called.
*/
-void visit_end_struct(Visitor *v, Error **errp);
+void visit_end_struct(Visitor *v);
/*** Visiting lists ***/
diff --git a/qapi/opts-visitor.c b/qapi/opts-visitor.c
index 4cb6436..ece0598 100644
--- a/qapi/opts-visitor.c
+++ b/qapi/opts-visitor.c
@@ -159,13 +159,13 @@
static void
-opts_end_struct(Visitor *v, Error **errp)
+opts_check_struct(Visitor *v, Error **errp)
{
OptsVisitor *ov = to_ov(v);
GHashTableIter iter;
GQueue *any;
- if (--ov->depth > 0) {
+ if (ov->depth > 0) {
return;
}
@@ -177,6 +177,18 @@
first = g_queue_peek_head(any);
error_setg(errp, QERR_INVALID_PARAMETER, first->name);
}
+}
+
+
+static void
+opts_end_struct(Visitor *v)
+{
+ OptsVisitor *ov = to_ov(v);
+
+ if (--ov->depth > 0) {
+ return;
+ }
+
g_hash_table_destroy(ov->unprocessed_opts);
ov->unprocessed_opts = NULL;
if (ov->fake_id_opt) {
@@ -516,6 +528,7 @@
ov->visitor.type = VISITOR_INPUT;
ov->visitor.start_struct = &opts_start_struct;
+ ov->visitor.check_struct = &opts_check_struct;
ov->visitor.end_struct = &opts_end_struct;
ov->visitor.start_list = &opts_start_list;
diff --git a/qapi/qapi-dealloc-visitor.c b/qapi/qapi-dealloc-visitor.c
index 413d525..9005bad 100644
--- a/qapi/qapi-dealloc-visitor.c
+++ b/qapi/qapi-dealloc-visitor.c
@@ -67,7 +67,7 @@
qapi_dealloc_push(qov, obj);
}
-static void qapi_dealloc_end_struct(Visitor *v, Error **errp)
+static void qapi_dealloc_end_struct(Visitor *v)
{
QapiDeallocVisitor *qov = to_qov(v);
void **obj = qapi_dealloc_pop(qov);
diff --git a/qapi/qapi-visit-core.c b/qapi/qapi-visit-core.c
index fe6afe8..58144f6 100644
--- a/qapi/qapi-visit-core.c
+++ b/qapi/qapi-visit-core.c
@@ -36,9 +36,16 @@
error_propagate(errp, err);
}
-void visit_end_struct(Visitor *v, Error **errp)
+void visit_check_struct(Visitor *v, Error **errp)
{
- v->end_struct(v, errp);
+ if (v->check_struct) {
+ v->check_struct(v, errp);
+ }
+}
+
+void visit_end_struct(Visitor *v)
+{
+ v->end_struct(v);
}
void visit_start_list(Visitor *v, const char *name, Error **errp)
diff --git a/qapi/qmp-input-visitor.c b/qapi/qmp-input-visitor.c
index 30e7cb3..90b9df1 100644
--- a/qapi/qmp-input-visitor.c
+++ b/qapi/qmp-input-visitor.c
@@ -125,9 +125,11 @@
}
-static void qmp_input_pop(QmpInputVisitor *qiv, Error **errp)
+static void qmp_input_check_struct(Visitor *v, Error **errp)
{
+ QmpInputVisitor *qiv = to_qiv(v);
StackObject *tos = &qiv->stack[qiv->nb_stack - 1];
+
assert(qiv->nb_stack > 0);
if (qiv->strict) {
@@ -140,6 +142,20 @@
if (g_hash_table_iter_next(&iter, (void **)&key, NULL)) {
error_setg(errp, QERR_QMP_EXTRA_MEMBER, key);
}
+ }
+ }
+}
+
+static void qmp_input_pop(Visitor *v)
+{
+ QmpInputVisitor *qiv = to_qiv(v);
+ StackObject *tos = &qiv->stack[qiv->nb_stack - 1];
+
+ assert(qiv->nb_stack > 0);
+
+ if (qiv->strict) {
+ GHashTable * const top_ht = qiv->stack[qiv->nb_stack - 1].h;
+ if (top_ht) {
g_hash_table_unref(top_ht);
}
tos->h = NULL;
@@ -175,12 +191,6 @@
}
}
-static void qmp_input_end_struct(Visitor *v, Error **errp)
-{
- QmpInputVisitor *qiv = to_qiv(v);
-
- qmp_input_pop(qiv, errp);
-}
static void qmp_input_start_list(Visitor *v, const char *name, Error **errp)
{
@@ -218,12 +228,6 @@
return entry;
}
-static void qmp_input_end_list(Visitor *v)
-{
- QmpInputVisitor *qiv = to_qiv(v);
-
- qmp_input_pop(qiv, &error_abort);
-}
static void qmp_input_start_alternate(Visitor *v, const char *name,
GenericAlternate **obj, size_t size,
@@ -383,10 +387,11 @@
v->visitor.type = VISITOR_INPUT;
v->visitor.start_struct = qmp_input_start_struct;
- v->visitor.end_struct = qmp_input_end_struct;
+ v->visitor.check_struct = qmp_input_check_struct;
+ v->visitor.end_struct = qmp_input_pop;
v->visitor.start_list = qmp_input_start_list;
v->visitor.next_list = qmp_input_next_list;
- v->visitor.end_list = qmp_input_end_list;
+ v->visitor.end_list = qmp_input_pop;
v->visitor.start_alternate = qmp_input_start_alternate;
v->visitor.type_int64 = qmp_input_type_int64;
v->visitor.type_uint64 = qmp_input_type_uint64;
diff --git a/qapi/qmp-output-visitor.c b/qapi/qmp-output-visitor.c
index 4e21f1d..232ad58 100644
--- a/qapi/qmp-output-visitor.c
+++ b/qapi/qmp-output-visitor.c
@@ -111,7 +111,7 @@
qmp_output_push(qov, dict);
}
-static void qmp_output_end_struct(Visitor *v, Error **errp)
+static void qmp_output_end_struct(Visitor *v)
{
QmpOutputVisitor *qov = to_qov(v);
QObject *value = qmp_output_pop(qov);
diff --git a/qom/object.c b/qom/object.c
index 8e6e68d..3bc8a00 100644
--- a/qom/object.c
+++ b/qom/object.c
@@ -2036,10 +2036,9 @@
if (err) {
goto out_end;
}
+ visit_check_struct(v, &err);
out_end:
- error_propagate(errp, err);
- err = NULL;
- visit_end_struct(v, errp);
+ visit_end_struct(v);
out:
error_propagate(errp, err);
diff --git a/qom/object_interfaces.c b/qom/object_interfaces.c
index cad5542..51e62e2 100644
--- a/qom/object_interfaces.c
+++ b/qom/object_interfaces.c
@@ -42,7 +42,7 @@
char *type = NULL;
char *id = NULL;
Object *obj = NULL;
- Error *local_err = NULL, *end_err = NULL;
+ Error *local_err = NULL;
QDict *pdict;
pdict = qdict_clone_shallow(qdict);
@@ -63,21 +63,15 @@
if (local_err) {
goto out_visit;
}
-
- obj = user_creatable_add_type(type, id, pdict, v, &local_err);
+ visit_check_struct(v, &local_err);
if (local_err) {
goto out_visit;
}
- out_visit:
- visit_end_struct(v, &end_err);
- if (end_err) {
- error_propagate(&local_err, end_err);
- if (obj) {
- user_creatable_del(id, NULL);
- }
- goto out;
- }
+ obj = user_creatable_add_type(type, id, pdict, v, &local_err);
+
+out_visit:
+ visit_end_struct(v);
out:
QDECREF(pdict);
@@ -130,7 +124,10 @@
break;
}
}
- visit_end_struct(v, local_err ? NULL : &local_err);
+ if (!local_err) {
+ visit_check_struct(v, &local_err);
+ }
+ visit_end_struct(v);
if (local_err) {
goto out;
}
diff --git a/scripts/qapi-commands.py b/scripts/qapi-commands.py
index 04549fa..8c6acb3 100644
--- a/scripts/qapi-commands.py
+++ b/scripts/qapi-commands.py
@@ -126,7 +126,10 @@
goto out;
}
visit_type_%(c_name)s_members(v, &arg, &err);
- visit_end_struct(v, err ? NULL : &err);
+ if (!err) {
+ visit_check_struct(v, &err);
+ }
+ visit_end_struct(v);
if (err) {
goto out;
}
@@ -157,7 +160,7 @@
v = qapi_dealloc_get_visitor(qdv);
visit_start_struct(v, NULL, NULL, 0, NULL);
visit_type_%(c_name)s_members(v, &arg, NULL);
- visit_end_struct(v, NULL);
+ visit_end_struct(v);
qapi_dealloc_visitor_cleanup(qdv);
''',
c_name=arg_type.c_name())
diff --git a/scripts/qapi-event.py b/scripts/qapi-event.py
index 9b5c5b5..21fb167 100644
--- a/scripts/qapi-event.py
+++ b/scripts/qapi-event.py
@@ -98,7 +98,10 @@
goto out;
}
visit_type_%(c_name)s_members(v, ¶m, &err);
- visit_end_struct(v, err ? NULL : &err);
+ if (!err) {
+ visit_check_struct(v, &err);
+ }
+ visit_end_struct(v);
if (err) {
goto out;
}
diff --git a/scripts/qapi-visit.py b/scripts/qapi-visit.py
index 31d2330..bdf8971 100644
--- a/scripts/qapi-visit.py
+++ b/scripts/qapi-visit.py
@@ -186,9 +186,10 @@
break;
}
visit_type_%(c_type)s_members(v, &(*obj)->u.%(c_name)s, &err);
- error_propagate(errp, err);
- err = NULL;
- visit_end_struct(v, &err);
+ if (!err) {
+ visit_check_struct(v, &err);
+ }
+ visit_end_struct(v);
''',
c_type=var.type.c_name(),
c_name=c_name(var.name))
@@ -236,10 +237,12 @@
goto out_obj;
}
visit_type_%(c_name)s_members(v, *obj, &err);
- error_propagate(errp, err);
- err = NULL;
+ if (err) {
+ goto out_obj;
+ }
+ visit_check_struct(v, &err);
out_obj:
- visit_end_struct(v, &err);
+ visit_end_struct(v);
out:
error_propagate(errp, err);
}
diff --git a/tests/test-qmp-input-visitor.c b/tests/test-qmp-input-visitor.c
index 10e00ec..6617276 100644
--- a/tests/test-qmp-input-visitor.c
+++ b/tests/test-qmp-input-visitor.c
@@ -303,7 +303,8 @@
error_free_or_abort(&err);
visit_type_null(v, "b", &err);
error_free_or_abort(&err);
- visit_end_struct(v, &error_abort);
+ visit_check_struct(v, &error_abort);
+ visit_end_struct(v);
}
static void test_visitor_in_union_flat(TestInputVisitorData *data,
diff --git a/tests/test-qmp-output-visitor.c b/tests/test-qmp-output-visitor.c
index 5543511..1f80e69 100644
--- a/tests/test-qmp-output-visitor.c
+++ b/tests/test-qmp-output-visitor.c
@@ -498,7 +498,8 @@
visit_start_struct(data->ov, NULL, NULL, 0, &error_abort);
visit_type_null(data->ov, "a", &error_abort);
- visit_end_struct(data->ov, &error_abort);
+ visit_check_struct(data->ov, &error_abort);
+ visit_end_struct(data->ov);
arg = qmp_output_get_qobject(data->qov);
g_assert(qobject_type(arg) == QTYPE_QDICT);
qdict = qobject_to_qdict(arg);
