qapi: Change visit_start_implicit_struct to visit_start_alternate

After recent changes, the only remaining use of
visit_start_implicit_struct() is for allocating the space needed
when visiting an alternate.  Since the term 'implicit struct' is
hard to explain, rename the function to its current usage.  While
at it, we can merge the functionality of visit_get_next_type()
into the same function, making it more like visit_start_struct().

Generated code is now slightly smaller:

| {
|     Error *err = NULL;
|
|-    visit_start_implicit_struct(v, (void**) obj, sizeof(BlockdevRef), &err);
|+    visit_start_alternate(v, name, (GenericAlternate **)obj, sizeof(**obj),
|+                          true, &err);
|     if (err) {
|         goto out;
|     }
|-    visit_get_next_type(v, name, &(*obj)->type, true, &err);
|-    if (err) {
|-        goto out_obj;
|-    }
|     switch ((*obj)->type) {
|     case QTYPE_QDICT:
|         visit_start_struct(v, name, NULL, 0, &err);
...
|     }
|-out_obj:
|-    visit_end_implicit_struct(v);
|+    visit_end_alternate(v);
| out:
|     error_propagate(errp, err);
| }

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1455778109-6278-16-git-send-email-eblake@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>

1 files changed, 9 insertions, 15 deletions

diff --git a/qapi/qmp-input-visitor.c b/qapi/qmp-input-visitor.c
index 26216604cc..e6598327c3 100644
--- a/qapi/qmp-input-visitor.c
+++ b/qapi/qmp-input-visitor.c
@@ -143,14 +143,6 @@ static void qmp_input_end_struct(Visitor *v, Error **errp)
     qmp_input_pop(qiv, errp);
 }
 
-static void qmp_input_start_implicit_struct(Visitor *v, void **obj,
-                                            size_t size, Error **errp)
-{
-    if (obj) {
-        *obj = g_malloc0(size);
-    }
-}
-
 static void qmp_input_start_list(Visitor *v, const char *name, Error **errp)
 {
     QmpInputVisitor *qiv = to_qiv(v);
@@ -202,19 +194,22 @@ static void qmp_input_end_list(Visitor *v)
     qmp_input_pop(qiv, &error_abort);
 }
 
-static void qmp_input_get_next_type(Visitor *v, const char *name, QType *type,
-                                    bool promote_int, Error **errp)
+static void qmp_input_start_alternate(Visitor *v, const char *name,
+                                      GenericAlternate **obj, size_t size,
+                                      bool promote_int, Error **errp)
 {
     QmpInputVisitor *qiv = to_qiv(v);
     QObject *qobj = qmp_input_get_object(qiv, name, false);
 
     if (!qobj) {
+        *obj = NULL;
         error_setg(errp, QERR_MISSING_PARAMETER, name ? name : "null");
         return;
     }
-    *type = qobject_type(qobj);
-    if (promote_int && *type == QTYPE_QINT) {
-        *type = QTYPE_QFLOAT;
+    *obj = g_malloc0(size);
+    (*obj)->type = qobject_type(qobj);
+    if (promote_int && (*obj)->type == QTYPE_QINT) {
+        (*obj)->type = QTYPE_QFLOAT;
     }
 }
 
@@ -345,10 +340,10 @@ QmpInputVisitor *qmp_input_visitor_new(QObject *obj)
 
     v->visitor.start_struct = qmp_input_start_struct;
     v->visitor.end_struct = qmp_input_end_struct;
-    v->visitor.start_implicit_struct = qmp_input_start_implicit_struct;
     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.start_alternate = qmp_input_start_alternate;
     v->visitor.type_enum = input_type_enum;
     v->visitor.type_int64 = qmp_input_type_int64;
     v->visitor.type_uint64 = qmp_input_type_uint64;
@@ -357,7 +352,6 @@ QmpInputVisitor *qmp_input_visitor_new(QObject *obj)
     v->visitor.type_number = qmp_input_type_number;
     v->visitor.type_any = qmp_input_type_any;
     v->visitor.optional = qmp_input_optional;
-    v->visitor.get_next_type = qmp_input_get_next_type;
 
     qmp_input_push(v, obj, NULL);
     qobject_incref(obj);