diff options
author | Markus Armbruster <armbru@redhat.com> | 2018-12-18 19:22:21 +0100 |
---|---|---|
committer | Markus Armbruster <armbru@redhat.com> | 2019-01-24 10:01:05 +0100 |
commit | a95291007b2478fcf32a2d71bf133b688bb4b675 (patch) | |
tree | 525e8adca1e42d685fc6467fa9486c7160fb16a4 /qapi | |
parent | 900cbbde3f3b6467a893b7b2bbcb04b4ba4be7d5 (diff) |
qapi: Eliminate indirection through qmp_event_get_func_emit()
The qapi_event_send_FOO() functions emit events like this:
QMPEventFuncEmit emit;
emit = qmp_event_get_func_emit();
if (!emit) {
return;
}
qmp = qmp_event_build_dict("FOO");
[put event arguments into @qmp...]
emit(QAPI_EVENT_FOO, qmp);
The value of qmp_event_get_func_emit() depends only on the program:
* In qemu-system-FOO, it's always monitor_qapi_event_queue.
* In tests/test-qmp-event, it's always event_test_emit.
* In all other programs, it's always null.
This is exactly the kind of dependence the linker is supposed to
resolve; we don't actually need an indirection.
Note that things would fall apart if we linked more than one QAPI
schema into a single program: each set of qapi_event_send_FOO() uses
its own event enumeration, yet they share a single emit function.
Which takes the event enumeration as an argument. Which one if
there's more than one?
More seriously: how does this work even now? qemu-system-FOO wants
QAPIEvent, and passes a function taking that to
qmp_event_set_func_emit(). test-qmp-event wants test_QAPIEvent, and
passes a function taking that to qmp_event_set_func_emit().
It works by type trickery, of course:
typedef void (*QMPEventFuncEmit)(unsigned event, QDict *dict);
void qmp_event_set_func_emit(QMPEventFuncEmit emit);
QMPEventFuncEmit qmp_event_get_func_emit(void);
We use unsigned instead of the enumeration type. Relies on both
enumerations boiling down to unsigned, which happens to be true for
the compilers we use.
Clean this up as follows:
* Generate qapi_event_send_FOO() that call PREFIX_qapi_event_emit()
instead of the value of qmp_event_set_func_emit().
* Generate a prototype for PREFIX_qapi_event_emit() into
qapi-events.h.
* PREFIX_ is empty for qapi/qapi-schema.json, and test_ for
tests/qapi-schema/qapi-schema-test.json. It's qga_ for
qga/qapi-schema.json, and doc-good- for
tests/qapi-schema/doc-good.json, but those don't define any events.
* Rename monitor_qapi_event_queue() to qapi_event_emit() instead of
passing it to qmp_event_set_func_emit(). This takes care of
qemu-system-FOO.
* Rename event_test_emit() to test_qapi_event_emit() instead of
passing it to qmp_event_set_func_emit(). This takes care of
tests/test-qmp-event.
* Add a qapi_event_emit() that does nothing to stubs/monitor.c. This
takes care of all other programs that link code emitting QMP events.
* Drop qmp_event_set_func_emit(), qmp_event_get_func_emit().
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20181218182234.28876-3-armbru@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
[Commit message typos fixed]
Diffstat (limited to 'qapi')
-rw-r--r-- | qapi/qmp-event.c | 12 |
1 files changed, 0 insertions, 12 deletions
diff --git a/qapi/qmp-event.c b/qapi/qmp-event.c index 5b8854043e..81ddd5331f 100644 --- a/qapi/qmp-event.c +++ b/qapi/qmp-event.c @@ -19,18 +19,6 @@ #include "qapi/qmp/qdict.h" #include "qapi/qmp/qjson.h" -static QMPEventFuncEmit qmp_emit; - -void qmp_event_set_func_emit(QMPEventFuncEmit emit) -{ - qmp_emit = emit; -} - -QMPEventFuncEmit qmp_event_get_func_emit(void) -{ - return qmp_emit; -} - static void timestamp_put(QDict *qdict) { int err; |