qapi: New QAPISchemaBranches, QAPISchemaAlternatives

QAPISchemaVariants represents either a union type's branches, or an
alternate type's alternatives.  Much of its code is conditional on
which one it actually is.

Create QAPISchemaBranches for branches, and QAPISchemaAlternatives for
alternatives, both subtypes of QAPISchemaVariants.

Replace QAPISchemaVariants by one of them where possible.  Keep it
only where we actually deal with either of them.

QAPISchemaVariants.__init__() takes @tag_name and @tag_member, where
exactly one must be None: @tag_name for alternatives, @tag_member for
branches.  Let QAPISchemaBranches.__init__() take just @tag_name, and
QAPISchemaAlternatives.__init__() take just @tag_member.

A later patch will move the conditional code to the subtypes.

Signed-off-by: Markus Armbruster <armbru@redhat.com>

1 files changed, 6 insertions, 5 deletions

diff --git a/scripts/qapi/visit.py b/scripts/qapi/visit.py
index a21b7b1468..990685498f 100644
--- a/scripts/qapi/visit.py
+++ b/scripts/qapi/visit.py
@@ -28,6 +28,8 @@ from .gen import (
 )
 from .schema import (
     QAPISchema,
+    QAPISchemaAlternatives,
+    QAPISchemaBranches,
     QAPISchemaEnumMember,
     QAPISchemaEnumType,
     QAPISchemaFeature,
@@ -35,7 +37,6 @@ from .schema import (
     QAPISchemaObjectType,
     QAPISchemaObjectTypeMember,
     QAPISchemaType,
-    QAPISchemaVariants,
 )
 from .source import QAPISourceInfo
 
@@ -63,7 +64,7 @@ bool visit_type_%(c_name)s_members(Visitor *v, %(c_name)s *obj, Error **errp);
 def gen_visit_object_members(name: str,
                              base: Optional[QAPISchemaObjectType],
                              members: List[QAPISchemaObjectTypeMember],
-                             variants: Optional[QAPISchemaVariants]) -> str:
+                             variants: Optional[QAPISchemaBranches]) -> str:
     ret = mcgen('''
 
 bool visit_type_%(c_name)s_members(Visitor *v, %(c_name)s *obj, Error **errp)
@@ -222,7 +223,7 @@ bool visit_type_%(c_name)s(Visitor *v, const char *name,
                  c_name=c_name(name))
 
 
-def gen_visit_alternate(name: str, variants: QAPISchemaVariants) -> str:
+def gen_visit_alternate(name: str, variants: QAPISchemaAlternatives) -> str:
     ret = mcgen('''
 
 bool visit_type_%(c_name)s(Visitor *v, const char *name,
@@ -393,7 +394,7 @@ class QAPISchemaGenVisitVisitor(QAPISchemaModularCVisitor):
                           features: List[QAPISchemaFeature],
                           base: Optional[QAPISchemaObjectType],
                           members: List[QAPISchemaObjectTypeMember],
-                          variants: Optional[QAPISchemaVariants]) -> None:
+                          variants: Optional[QAPISchemaBranches]) -> None:
         # Nothing to do for the special empty builtin
         if name == 'q_empty':
             return
@@ -413,7 +414,7 @@ class QAPISchemaGenVisitVisitor(QAPISchemaModularCVisitor):
                              info: Optional[QAPISourceInfo],
                              ifcond: QAPISchemaIfCond,
                              features: List[QAPISchemaFeature],
-                             variants: QAPISchemaVariants) -> None:
+                             variants: QAPISchemaAlternatives) -> None:
         with ifcontext(ifcond, self._genh, self._genc):
             self._genh.add(gen_visit_decl(name))
             self._genc.add(gen_visit_alternate(name, variants))