From 2b162ccbe875e5323fc04c1009addbdea4d35220 Mon Sep 17 00:00:00 2001
From: Markus Armbruster <armbru@redhat.com>
Date: Wed, 16 Sep 2015 13:06:09 +0200
Subject: qapi-types: Convert to QAPISchemaVisitor, fixing flat unions

Fixes flat unions to get the base's base members.  Test case is from
commit 2fc0043, in qapi-schema-test.json:

    { 'union': 'UserDefFlatUnion',
      'base': 'UserDefUnionBase',
      'discriminator': 'enum1',
      'data': { 'value1' : 'UserDefA',
                'value2' : 'UserDefB',
                'value3' : 'UserDefB' } }

    { 'struct': 'UserDefUnionBase',
      'base': 'UserDefZero',
      'data': { 'string': 'str', 'enum1': 'EnumOne' } }

    { 'struct': 'UserDefZero',
      'data': { 'integer': 'int' } }

Patch's effect on UserDefFlatUnion:

     struct UserDefFlatUnion {
         /* Members inherited from UserDefUnionBase: */
    +    int64_t integer;
         char *string;
         EnumOne enum1;
         /* Own members: */
         union { /* union tag is @enum1 */
             void *data;
             UserDefA *value1;
             UserDefB *value2;
             UserDefB *value3;
         };
     };

Flat union visitors remain broken.  They'll be fixed next.

Code is generated in a different order now, but that doesn't matter.

The two guards QAPI_TYPES_BUILTIN_STRUCT_DECL and
QAPI_TYPES_BUILTIN_CLEANUP_DECL are replaced by just
QAPI_TYPES_BUILTIN.

Two ugly special cases for simple unions now stand out like sore
thumbs:

1. The type tag is named 'type' everywhere, except in generated C,
   where it's 'kind'.

2. QAPISchema lowers simple unions to semantically equivalent flat
   unions.  However, the C generated for a simple unions differs from
   the C generated for its equivalent flat union, and we therefore
   need special code to preserve that pointless difference for now.

Mark both TODO.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
 scripts/qapi.py | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

(limited to 'scripts/qapi.py')

diff --git a/scripts/qapi.py b/scripts/qapi.py
index 36e0702..c18400d 100644
--- a/scripts/qapi.py
+++ b/scripts/qapi.py
@@ -995,7 +995,6 @@ class QAPISchemaObjectTypeVariants(object):
             vseen = dict(seen)
             v.check(schema, self.tag_member.type, vseen)
 
-
 class QAPISchemaObjectTypeVariant(QAPISchemaObjectTypeMember):
     def __init__(self, name, typ):
         QAPISchemaObjectTypeMember.__init__(self, name, typ, False)
@@ -1004,6 +1003,15 @@ class QAPISchemaObjectTypeVariant(QAPISchemaObjectTypeMember):
         QAPISchemaObjectTypeMember.check(self, schema, [], seen)
         assert self.name in tag_type.values
 
+    # This function exists to support ugly simple union special cases
+    # TODO get rid of them, and drop the function
+    def simple_union_type(self):
+        if isinstance(self.type, QAPISchemaObjectType) and not self.type.info:
+            assert len(self.type.members) == 1
+            assert not self.type.variants
+            return self.type.members[0].type
+        return None
+
 
 class QAPISchemaAlternateType(QAPISchemaType):
     def __init__(self, name, info, variants):
-- 
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