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3b098d5697
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>
|
||
|---|---|---|
| .. | ||
| specs | ||
| aio_notify_accept.promela | ||
| aio_notify_bug.promela | ||
| aio_notify.promela | ||
| atomics.txt | ||
| bitmaps.md | ||
| blkdebug.txt | ||
| blkverify.txt | ||
| bootindex.txt | ||
| build-system.txt | ||
| ccid.txt | ||
| ich9-ehci-uhci.cfg | ||
| igd-assign.txt | ||
| image-fuzzer.txt | ||
| live-block-ops.txt | ||
| memory-hotplug.txt | ||
| memory.txt | ||
| migration.txt | ||
| multi-thread-compression.txt | ||
| multiple-iothreads.txt | ||
| multiseat.txt | ||
| pci_expander_bridge.txt | ||
| q35-chipset.cfg | ||
| qapi-code-gen.txt | ||
| qcow2-cache.txt | ||
| qdev-device-use.txt | ||
| qemupciserial.inf | ||
| qmp-events.txt | ||
| qmp-intro.txt | ||
| qmp-spec.txt | ||
| rcu.txt | ||
| rdma.txt | ||
| replay.txt | ||
| spice-port-fqdn.txt | ||
| throttle.txt | ||
| tracing.txt | ||
| usb2.txt | ||
| usb-storage.txt | ||
| virtio-balloon-stats.txt | ||
| virtio-migration.txt | ||
| vnc-ledstate-Pseudo-encoding.txt | ||
| win32-qemu-event.promela | ||
| writing-qmp-commands.txt | ||
| xbzrle.txt | ||
| xen-save-devices-state.txt | ||