qapi: Anonymous unions
The discriminator for anonymous unions is the data type. This allows to
have a union type that allows both of these:
{ 'file': 'my_existing_block_device_id' }
{ 'file': { 'filename': '/tmp/mydisk.qcow2', 'read-only': true } }
Unions like this are specified in the schema with an empty dict as
discriminator. For this example you could take:
{ 'union': 'BlockRef',
'discriminator': {},
'data': { 'definition': 'BlockOptions',
'reference': 'str' } }
{ 'type': 'ExampleObject',
'data: { 'file': 'BlockRef' } }
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
diff --git a/scripts/qapi-visit.py b/scripts/qapi-visit.py
index 87d5f15..597cca4 100644
--- a/scripts/qapi-visit.py
+++ b/scripts/qapi-visit.py
@@ -176,6 +176,49 @@
''',
name=name)
+def generate_visit_anon_union(name, members):
+ ret = mcgen('''
+
+void visit_type_%(name)s(Visitor *m, %(name)s ** obj, const char *name, Error **errp)
+{
+ Error *err = NULL;
+
+ if (!error_is_set(errp)) {
+ visit_start_implicit_struct(m, (void**) obj, sizeof(%(name)s), &err);
+ visit_get_next_type(m, (int*) &(*obj)->kind, %(name)s_qtypes, name, &err);
+ switch ((*obj)->kind) {
+''',
+ name=name)
+
+ for key in members:
+ assert (members[key] in builtin_types
+ or find_struct(members[key])
+ or find_union(members[key])), "Invalid anonymous union member"
+
+ ret += mcgen('''
+ case %(abbrev)s_KIND_%(enum)s:
+ visit_type_%(c_type)s(m, &(*obj)->%(c_name)s, name, &err);
+ break;
+''',
+ abbrev = de_camel_case(name).upper(),
+ enum = c_fun(de_camel_case(key),False).upper(),
+ c_type = type_name(members[key]),
+ c_name = c_fun(key))
+
+ ret += mcgen('''
+ default:
+ abort();
+ }
+ error_propagate(errp, err);
+ err = NULL;
+ visit_end_implicit_struct(m, &err);
+ }
+}
+''')
+
+ return ret
+
+
def generate_visit_union(expr):
name = expr['union']
@@ -184,6 +227,10 @@
base = expr.get('base')
discriminator = expr.get('discriminator')
+ if discriminator == {}:
+ assert not base
+ return generate_visit_anon_union(name, members)
+
ret = generate_visit_enum('%sKind' % name, members.keys())
if base: