qapi script: use same function to generate enum string

Prior to this patch, qapi-visit.py used custom code to generate enum
names used for handling a qapi union. Fix it to instead reuse common
code, with identical generated results, and allowing future updates to
generation to only need to touch one place.

Signed-off-by: Wenchao Xia <wenchaoqemu@gmail.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>

scripts/qapi-types.py

@@ -144,11 +144,11 @@ typedef enum %(name)s
 
     i = 0
     for value in enum_values:
+        enum_full_value = generate_enum_full_value(name, value)
         enum_decl += mcgen('''
-    %(abbrev)s_%(value)s = %(i)d,
+    %(enum_full_value)s = %(i)d,
 ''',
-                     abbrev=de_camel_case(name).upper(),
-                     value=generate_enum_name(value),
+                     enum_full_value = enum_full_value,
                      i=i)
         i += 1
 

scripts/qapi-visit.py

@@ -214,18 +214,22 @@ void visit_type_%(name)s(Visitor *m, %(name)s ** obj, const char *name, Error **
 ''',
     name=name)
 
+    # For anon union, always use the default enum type automatically generated
+    # as "'%sKind' % (name)"
+    disc_type = '%sKind' % (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"
 
+        enum_full_value = generate_enum_full_value(disc_type, key)
         ret += mcgen('''
-        case %(abbrev)s_KIND_%(enum)s:
+        case %(enum_full_value)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(),
+                enum_full_value = enum_full_value,
                 c_type = type_name(members[key]),
                 c_name = c_fun(key))
 
@@ -255,7 +259,10 @@ def generate_visit_union(expr):
         assert not base
         return generate_visit_anon_union(name, members)
 
+    # There will always be a discriminator in the C switch code, by default it
+    # is an enum type generated silently as "'%sKind' % (name)"
     ret = generate_visit_enum('%sKind' % name, members.keys())
+    disc_type = '%sKind' % (name)
 
     if base:
         base_fields = find_struct(base)['data']
@@ -313,13 +320,13 @@ void visit_type_%(name)s(Visitor *m, %(name)s ** obj, const char *name, Error **
                     visit_end_implicit_struct(m, &err);
                 }'''
 
+        enum_full_value = generate_enum_full_value(disc_type, key)
         ret += mcgen('''
-            case %(abbrev)s_KIND_%(enum)s:
+            case %(enum_full_value)s:
                 ''' + fmt + '''
                 break;
 ''',
-                abbrev = de_camel_case(name).upper(),
-                enum = c_fun(de_camel_case(key),False).upper(),
+                enum_full_value = enum_full_value,
                 c_type=type_name(members[key]),
                 c_name=c_fun(key))
 

scripts/qapi.py

@@ -468,12 +468,17 @@ def guardend(name):
 ''',
                  name=guardname(name))
 
-def generate_enum_name(name):
-    if name.isupper():
-        return c_fun(name, False)
+def _generate_enum_value_string(value):
+    if value.isupper():
+        return c_fun(value, False)
     new_name = ''
-    for c in c_fun(name, False):
+    for c in c_fun(value, False):
         if c.isupper():
             new_name += '_'
         new_name += c
     return new_name.lstrip('_').upper()
+
+def generate_enum_full_value(enum_name, enum_value):
+    abbrev_string = de_camel_case(enum_name).upper()
+    value_string = _generate_enum_value_string(enum_value)
+    return "%s_%s" % (abbrev_string, value_string)