[Qemu-devel] [PATCH 08/17] qapi-visit: Factor out gen_visit_fields_call()

[Eric Blake]

Upcoming patches will be adding several contexts where we want
to handle the visit of an implicit type (an anonymous base type,
or an anonymous branch of a flat union) by directly inlining
the visit of each of the implicit type's member fields. The work
is made easier by factoring out a new helper method,
gen_visit_fields_call(), so that the caller doesn't need to
care whether the type it is visiting is implicit or normal.

For now, the only implicit type we encounter are the branches
of a simple union; the initial implementation of the helper
method is hard-coded to that usage, but it gets us one step
closer to completely dropping the hack of simple_union_type().

Generated output is unchanged.

Signed-off-by: Eric Blake <address@hidden>
---
 scripts/qapi-visit.py | 48 ++++++++++++++++++++++++++----------------------
 1 file changed, 26 insertions(+), 22 deletions(-)

diff --git a/scripts/qapi-visit.py b/scripts/qapi-visit.py
index 2308268..ab773f6 100644
--- a/scripts/qapi-visit.py
+++ b/scripts/qapi-visit.py
@@ -31,7 +31,7 @@ void visit_type_%(c_name)s(Visitor *v, const char *name, 
%(c_type)sobj, Error **


 def gen_visit_fields_decl(typ):
-    if typ.name in struct_fields_seen:
+    if typ.is_implicit() or typ.name in struct_fields_seen:
         return ''
     struct_fields_seen.add(typ.name)
     return mcgen('''
@@ -41,6 +41,25 @@ static void visit_type_%(c_type)s_fields(Visitor *v, 
%(c_type)s *obj, Error **er
                  c_type=typ.c_name())


+def gen_visit_fields_call(typ, c_name):
+    ret = ''
+    assert isinstance(typ, QAPISchemaObjectType)
+    if typ.is_implicit():
+        # TODO ugly special case for simple union
+        assert len(typ.members) == 1
+        assert not typ.variants
+        ret += mcgen('''
+    visit_type_%(c_type)s(v, "data", %(c_name)s, &err);
+''',
+                     c_type=typ.members[0].type.c_name(), c_name=c_name)
+    else:
+        ret += mcgen('''
+    visit_type_%(c_type)s_fields(v, %(c_name)s, &err);
+''',
+                     c_type=typ.c_name(), c_name=c_name)
+    return ret
+
+
 def gen_visit_struct_fields(name, base, members, variants):
     ret = ''

@@ -48,9 +67,7 @@ def gen_visit_struct_fields(name, base, members, variants):
         ret += gen_visit_fields_decl(base)
     if variants:
         for var in variants.variants:
-            # Ugly special case for simple union TODO get rid of it
-            if not var.simple_union_type():
-                ret += gen_visit_fields_decl(var.type)
+            ret += gen_visit_fields_decl(var.type)

     struct_fields_seen.add(name)
     ret += mcgen('''
@@ -63,10 +80,7 @@ static void visit_type_%(c_name)s_fields(Visitor *v, 
%(c_name)s *obj, Error **er
                  c_name=c_name(name))

     if base:
-        ret += mcgen('''
-    visit_type_%(c_type)s_fields(v, (%(c_type)s *)obj, &err);
-''',
-                     c_type=base.c_name())
+        ret += gen_visit_fields_call(base, '(%s *)obj' % base.c_name())
         ret += gen_err_check()

     ret += gen_visit_fields(members, prefix='obj->')
@@ -78,26 +92,16 @@ static void visit_type_%(c_name)s_fields(Visitor *v, 
%(c_name)s *obj, Error **er
                      c_name=c_name(variants.tag_member.name))

         for var in variants.variants:
-            # TODO ugly special case for simple union
-            simple_union_type = var.simple_union_type()
             ret += mcgen('''
     case %(case)s:
 ''',
                          case=c_enum_const(variants.tag_member.type.name,
                                            var.name,
                                            variants.tag_member.type.prefix))
-            if simple_union_type:
-                ret += mcgen('''
-        visit_type_%(c_type)s(v, "data", &obj->u.%(c_name)s, &err);
-''',
-                             c_type=simple_union_type.c_name(),
-                             c_name=c_name(var.name))
-            else:
-                ret += mcgen('''
-        visit_type_%(c_type)s_fields(v, &obj->u.%(c_name)s, &err);
-''',
-                             c_type=var.type.c_name(),
-                             c_name=c_name(var.name))
+            push_indent()
+            ret += gen_visit_fields_call(var.type,
+                                         '&obj->u.' + c_name(var.name))
+            pop_indent()
             ret += mcgen('''
         break;
 ''')
-- 
2.5.0