qapi: Flat unions with arbitrary discriminator
Instead of the rather verbose syntax that distinguishes base and
subclass fields...
{ "type": "file",
"read-only": true,
"data": {
"filename": "test"
} }
...we can now have both in the same namespace, allowing a more direct
mapping of the command line, and moving fields between the common base
and subclasses without breaking the API:
{ "driver": "file",
"read-only": true,
"filename": "test" }
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 db6fa44..87d5f15 100644
--- a/scripts/qapi-visit.py
+++ b/scripts/qapi-visit.py
@@ -17,8 +17,30 @@
import getopt
import errno
-def generate_visit_struct_fields(field_prefix, members):
+def generate_visit_struct_fields(name, field_prefix, fn_prefix, members):
+ substructs = []
ret = ''
+ full_name = name if not fn_prefix else "%s_%s" % (name, fn_prefix)
+
+ for argname, argentry, optional, structured in parse_args(members):
+ if structured:
+ if not fn_prefix:
+ nested_fn_prefix = argname
+ else:
+ nested_fn_prefix = "%s_%s" % (fn_prefix, argname)
+
+ nested_field_prefix = "%s%s." % (field_prefix, argname)
+ ret += generate_visit_struct_fields(name, nested_field_prefix,
+ nested_fn_prefix, argentry)
+
+ ret += mcgen('''
+
+static void visit_type_%(full_name)s_fields(Visitor *m, %(name)s ** obj, Error **errp)
+{
+ Error *err = NULL;
+''',
+ name=name, full_name=full_name)
+ push_indent()
for argname, argentry, optional, structured in parse_args(members):
if optional:
@@ -31,7 +53,7 @@
push_indent()
if structured:
- ret += generate_visit_struct_body(field_prefix + argname, argname, argentry)
+ ret += generate_visit_struct_body(full_name, argname, argentry)
else:
ret += mcgen('''
visit_type_%(type)s(m, obj ? &(*obj)->%(c_prefix)s%(c_name)s : NULL, "%(name)s", &err);
@@ -47,6 +69,12 @@
visit_end_optional(m, &err);
''')
+ pop_indent()
+ ret += mcgen('''
+
+ error_propagate(errp, err);
+}
+''')
return ret
@@ -56,8 +84,9 @@
''')
push_indent()
+ full_name = name if not field_prefix else "%s_%s" % (field_prefix, name)
+
if len(field_prefix):
- field_prefix = field_prefix + "."
ret += mcgen('''
Error **errp = &err; /* from outer scope */
Error *err = NULL;
@@ -74,19 +103,13 @@
ret += mcgen('''
if (!err) {
if (!obj || *obj) {
-''')
- push_indent()
- push_indent()
+ visit_type_%(name)s_fields(m, obj, &err);
+ error_propagate(errp, err);
+ err = NULL;
+ }
+''',
+ name=full_name)
- ret += generate_visit_struct_fields(field_prefix, members)
- pop_indent()
- ret += mcgen('''
- error_propagate(errp, err);
- err = NULL;
-}
-''')
-
- pop_indent()
pop_indent()
ret += mcgen('''
/* Always call end_struct if start_struct succeeded. */
@@ -98,7 +121,9 @@
return ret
def generate_visit_struct(name, members):
- ret = mcgen('''
+ ret = generate_visit_struct_fields(name, "", "", members)
+
+ ret += mcgen('''
void visit_type_%(name)s(Visitor *m, %(name)s ** obj, const char *name, Error **errp)
{
@@ -157,9 +182,17 @@
members = expr['data']
base = expr.get('base')
+ discriminator = expr.get('discriminator')
ret = generate_visit_enum('%sKind' % name, members.keys())
+ if base:
+ base_fields = find_struct(base)['data']
+ if discriminator:
+ base_fields = base_fields.copy()
+ del base_fields[discriminator]
+ ret += generate_visit_struct_fields(name, "", "", base_fields)
+
ret += mcgen('''
void visit_type_%(name)s(Visitor *m, %(name)s ** obj, const char *name, Error **errp)
@@ -179,23 +212,34 @@
push_indent()
if base:
- struct = find_struct(base)
- push_indent()
- ret += generate_visit_struct_fields("", struct['data'])
- pop_indent()
+ ret += mcgen('''
+ visit_type_%(name)s_fields(m, obj, &err);
+''',
+ name=name)
pop_indent()
ret += mcgen('''
- visit_type_%(name)sKind(m, &(*obj)->kind, "type", &err);
+ visit_type_%(name)sKind(m, &(*obj)->kind, "%(type)s", &err);
if (!err) {
switch ((*obj)->kind) {
''',
- name=name)
+ name=name, type="type" if not discriminator else discriminator)
for key in members:
+ if not discriminator:
+ fmt = 'visit_type_%(c_type)s(m, &(*obj)->%(c_name)s, "data", &err);'
+ else:
+ fmt = '''visit_start_implicit_struct(m, (void**) &(*obj)->%(c_name)s, sizeof(%(c_type)s), &err);
+ if (!err) {
+ visit_type_%(c_type)s_fields(m, &(*obj)->%(c_name)s, &err);
+ error_propagate(errp, err);
+ err = NULL;
+ visit_end_implicit_struct(m, &err);
+ }'''
+
ret += mcgen('''
case %(abbrev)s_KIND_%(enum)s:
- visit_type_%(c_type)s(m, &(*obj)->%(c_name)s, "data", &err);
+ ''' + fmt + '''
break;
''',
abbrev = de_camel_case(name).upper(),