Merge remote-tracking branch 'remotes/armbru/tags/pull-qapi-2020-04-30' into staging

QAPI patches for 2020-04-30

# gpg: Signature made Thu 30 Apr 2020 06:29:18 BST
# gpg:                using RSA key 354BC8B3D7EB2A6B68674E5F3870B400EB918653
# gpg:                issuer "armbru@redhat.com"
# gpg: Good signature from "Markus Armbruster <armbru@redhat.com>" [full]
# gpg:                 aka "Markus Armbruster <armbru@pond.sub.org>" [full]
# Primary key fingerprint: 354B C8B3 D7EB 2A6B 6867  4E5F 3870 B400 EB91 8653

* remotes/armbru/tags/pull-qapi-2020-04-30:
  qapi: Generate simpler marshalling code when no arguments
  qapi: Disallow qmp_marshal_FOO(NULL, ...)
  qom: Simplify object_property_get_enum()
  qapi: Only input visitors can actually fail
  qapi: Assert non-input visitors see only valid alternate tags
  qapi: Clean up visitor's recovery from input with invalid type
  qapi: Assert non-input visitors see only valid narrow integers
  qapi: Assert output visitors see only valid enum values
  qapi: Fix Visitor contract for start_alternate()
  qapi: Assert incomplete object occurs only in dealloc visitor
  qapi: Polish prose in visitor.h
  qapi: Document @errp usage more thoroughly in visitor.h
  qapi: Fix typo in visit_start_list()'s contract
  qapi: Fix the virtual walk example in visitor.h's big comment
  qapi: Belatedly update visitor.h's big comment for QAPI modules
  qemu-option: Clean up after the previous commit
  qobject: Eliminate qdict_iter(), use qdict_first(), qdict_next()
  qobject: Eliminate qlist_iter(), use QLIST_FOREACH_ENTRY() instead
  qobject: Factor out helper json_pretty_newline()
  qobject: Clean up QLIST_FOREACH_ENTRY()

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

2 files changed, 31 insertions, 37 deletions

diff --git a/scripts/qapi/commands.py b/scripts/qapi/commands.py
index bc30876c88..6809b0fb6e 100644
--- a/scripts/qapi/commands.py
+++ b/scripts/qapi/commands.py
@@ -104,6 +104,7 @@ def gen_marshal(name, arg_type, boxed, ret_type):
 %(proto)s
 {
     Error *err = NULL;
+    Visitor *v;
 ''',
                 proto=build_marshal_proto(name))
 
@@ -114,44 +115,38 @@ def gen_marshal(name, arg_type, boxed, ret_type):
                      c_type=ret_type.c_type())
 
     if have_args:
-        visit_members = ('visit_type_%s_members(v, &arg, &err);'
-                         % arg_type.c_name())
         ret += mcgen('''
-    Visitor *v;
     %(c_name)s arg = {0};
-
 ''',
                      c_name=arg_type.c_name())
-    else:
-        visit_members = ''
-        ret += mcgen('''
-    Visitor *v = NULL;
-
-    if (args) {
-''')
-        push_indent()
 
     ret += mcgen('''
+
     v = qobject_input_visitor_new(QOBJECT(args));
     visit_start_struct(v, NULL, NULL, 0, &err);
     if (err) {
         goto out;
     }
-    %(visit_members)s
+''')
+
+    if have_args:
+        ret += mcgen('''
+    visit_type_%(c_arg_type)s_members(v, &arg, &err);
     if (!err) {
         visit_check_struct(v, &err);
     }
+''',
+                     c_arg_type=arg_type.c_name())
+    else:
+        ret += mcgen('''
+    visit_check_struct(v, &err);
+''')
+
+    ret += mcgen('''
     visit_end_struct(v, NULL);
     if (err) {
         goto out;
     }
-''',
-                 visit_members=visit_members)
-
-    if not have_args:
-        pop_indent()
-        ret += mcgen('''
-    }
 ''')
 
     ret += gen_call(name, arg_type, boxed, ret_type)
@@ -163,29 +158,20 @@ out:
     visit_free(v);
 ''')
 
+    ret += mcgen('''
+    v = qapi_dealloc_visitor_new();
+    visit_start_struct(v, NULL, NULL, 0, NULL);
+''')
+
     if have_args:
-        visit_members = ('visit_type_%s_members(v, &arg, NULL);'
-                         % arg_type.c_name())
-    else:
-        visit_members = ''
         ret += mcgen('''
-    if (args) {
-''')
-        push_indent()
+    visit_type_%(c_arg_type)s_members(v, &arg, NULL);
+''',
+                     c_arg_type=arg_type.c_name())
 
     ret += mcgen('''
-    v = qapi_dealloc_visitor_new();
-    visit_start_struct(v, NULL, NULL, 0, NULL);
-    %(visit_members)s
     visit_end_struct(v, NULL);
     visit_free(v);
-''',
-                 visit_members=visit_members)
-
-    if not have_args:
-        pop_indent()
-        ret += mcgen('''
-    }
 ''')
 
     ret += mcgen('''
diff --git a/scripts/qapi/visit.py b/scripts/qapi/visit.py
index 23d9194aa4..d5d7a1031f 100644
--- a/scripts/qapi/visit.py
+++ b/scripts/qapi/visit.py
@@ -189,6 +189,8 @@ void visit_type_%(c_name)s(Visitor *v, const char *name, %(c_name)s **obj, Error
         goto out;
     }
     if (!*obj) {
+        /* incomplete */
+        assert(visit_is_dealloc(v));
         goto out_obj;
     }
     switch ((*obj)->type) {
@@ -230,8 +232,12 @@ void visit_type_%(c_name)s(Visitor *v, const char *name, %(c_name)s **obj, Error
     case QTYPE_NONE:
         abort();
     default:
+        assert(visit_is_input(v));
         error_setg(&err, QERR_INVALID_PARAMETER_TYPE, name ? name : "null",
                    "%(name)s");
+        /* Avoid passing invalid *obj to qapi_free_%(c_name)s() */
+        g_free(*obj);
+        *obj = NULL;
     }
 out_obj:
     visit_end_alternate(v, (void **)obj);
@@ -260,6 +266,8 @@ void visit_type_%(c_name)s(Visitor *v, const char *name, %(c_name)s **obj, Error
         goto out;
     }
     if (!*obj) {
+        /* incomplete */
+        assert(visit_is_dealloc(v));
         goto out_obj;
     }
     visit_type_%(c_name)s_members(v, *obj, &err);