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authorEric Blake <eblake@redhat.com>2016-06-09 10:48:43 -0600
committerMarkus Armbruster <armbru@redhat.com>2016-07-06 10:52:04 +0200
commit3b098d56979d2f7fd707c5be85555d114353a28d (patch)
tree85f234e99b363f4417c0b4a09971ad63935031d9 /qom
parent23d1705f425ca847f11d92e4363cd7f67f369fd8 (diff)
qapi: Add new visit_complete() function
Making each output visitor provide its own output collection function was the only remaining reason for exposing visitor sub-types to the rest of the code base. Add a polymorphic visit_complete() function which is a no-op for input visitors, and which populates an opaque pointer for output visitors. For maximum type-safety, also add a parameter to the output visitor constructors with a type-correct version of the output pointer, and assert that the two uses match. This approach was considered superior to either passing the output parameter only during construction (action at a distance during visit_free() feels awkward) or only during visit_complete() (defeating type safety makes it easier to use incorrectly). Most callers were function-local, and therefore a mechanical conversion; the testsuite was a bit trickier, but the previous cleanup patch minimized the churn here. The visit_complete() function may be called at most once; doing so lets us use transfer semantics rather than duplication or ref-count semantics to get the just-built output back to the caller, even though it means our behavior is not idempotent. Generated code is simplified as follows for events: |@@ -26,7 +26,7 @@ void qapi_event_send_acpi_device_ost(ACP | QDict *qmp; | Error *err = NULL; | QMPEventFuncEmit emit; |- QmpOutputVisitor *qov; |+ QObject *obj; | Visitor *v; | q_obj_ACPI_DEVICE_OST_arg param = { | info |@@ -39,8 +39,7 @@ void qapi_event_send_acpi_device_ost(ACP | | qmp = qmp_event_build_dict("ACPI_DEVICE_OST"); | |- qov = qmp_output_visitor_new(); |- v = qmp_output_get_visitor(qov); |+ v = qmp_output_visitor_new(&obj); | | visit_start_struct(v, "ACPI_DEVICE_OST", NULL, 0, &err); | if (err) { |@@ -55,7 +54,8 @@ void qapi_event_send_acpi_device_ost(ACP | goto out; | } | |- qdict_put_obj(qmp, "data", qmp_output_get_qobject(qov)); |+ visit_complete(v, &obj); |+ qdict_put_obj(qmp, "data", obj); | emit(QAPI_EVENT_ACPI_DEVICE_OST, qmp, &err); and for commands: | { | Error *err = NULL; |- QmpOutputVisitor *qov = qmp_output_visitor_new(); | Visitor *v; | |- v = qmp_output_get_visitor(qov); |+ v = qmp_output_visitor_new(ret_out); | visit_type_AddfdInfo(v, "unused", &ret_in, &err); |- if (err) { |- goto out; |+ if (!err) { |+ visit_complete(v, ret_out); | } |- *ret_out = qmp_output_get_qobject(qov); |- |-out: | error_propagate(errp, err); Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1465490926-28625-13-git-send-email-eblake@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
Diffstat (limited to 'qom')
-rw-r--r--qom/object.c28
-rw-r--r--qom/qom-qobject.c10
2 files changed, 17 insertions, 21 deletions
diff --git a/qom/object.c b/qom/object.c
index 2407b667d9..8166b7dace 100644
--- a/qom/object.c
+++ b/qom/object.c
@@ -1221,7 +1221,6 @@ int object_property_get_enum(Object *obj, const char *name,
const char *typename, Error **errp)
{
Error *err = NULL;
- StringOutputVisitor *sov;
Visitor *v;
char *str;
int ret;
@@ -1241,15 +1240,14 @@ int object_property_get_enum(Object *obj, const char *name,
enumprop = prop->opaque;
- sov = string_output_visitor_new(false);
- v = string_output_get_visitor(sov);
+ v = string_output_visitor_new(false, &str);
object_property_get(obj, v, name, &err);
if (err) {
error_propagate(errp, err);
visit_free(v);
return 0;
}
- str = string_output_get_string(sov);
+ visit_complete(v, &str);
visit_free(v);
v = string_input_visitor_new(str);
visit_type_enum(v, name, &ret, enumprop->strings, errp);
@@ -1264,25 +1262,23 @@ void object_property_get_uint16List(Object *obj, const char *name,
uint16List **list, Error **errp)
{
Error *err = NULL;
- StringOutputVisitor *ov;
Visitor *v;
char *str;
- ov = string_output_visitor_new(false);
- object_property_get(obj, string_output_get_visitor(ov),
- name, &err);
+ v = string_output_visitor_new(false, &str);
+ object_property_get(obj, v, name, &err);
if (err) {
error_propagate(errp, err);
goto out;
}
- str = string_output_get_string(ov);
+ visit_complete(v, &str);
+ visit_free(v);
v = string_input_visitor_new(str);
visit_type_uint16List(v, NULL, list, errp);
g_free(str);
- visit_free(v);
out:
- visit_free(string_output_get_visitor(ov));
+ visit_free(v);
}
void object_property_parse(Object *obj, const char *string,
@@ -1296,21 +1292,21 @@ void object_property_parse(Object *obj, const char *string,
char *object_property_print(Object *obj, const char *name, bool human,
Error **errp)
{
- StringOutputVisitor *sov;
+ Visitor *v;
char *string = NULL;
Error *local_err = NULL;
- sov = string_output_visitor_new(human);
- object_property_get(obj, string_output_get_visitor(sov), name, &local_err);
+ v = string_output_visitor_new(human, &string);
+ object_property_get(obj, v, name, &local_err);
if (local_err) {
error_propagate(errp, local_err);
goto out;
}
- string = string_output_get_string(sov);
+ visit_complete(v, &string);
out:
- visit_free(string_output_get_visitor(sov));
+ visit_free(v);
return string;
}
diff --git a/qom/qom-qobject.c b/qom/qom-qobject.c
index 6714565f13..c225abcbad 100644
--- a/qom/qom-qobject.c
+++ b/qom/qom-qobject.c
@@ -33,14 +33,14 @@ QObject *object_property_get_qobject(Object *obj, const char *name,
{
QObject *ret = NULL;
Error *local_err = NULL;
- QmpOutputVisitor *qov;
+ Visitor *v;
- qov = qmp_output_visitor_new();
- object_property_get(obj, qmp_output_get_visitor(qov), name, &local_err);
+ v = qmp_output_visitor_new(&ret);
+ object_property_get(obj, v, name, &local_err);
if (!local_err) {
- ret = qmp_output_get_qobject(qov);
+ visit_complete(v, &ret);
}
error_propagate(errp, local_err);
- visit_free(qmp_output_get_visitor(qov));
+ visit_free(v);
return ret;
}