[Qemu-devel] [PULL 07/25] qapi-visit: Split off visit_type_FOO_fields forward decl

[Markus Armbruster <armbru@redhat.com>]

From: Eric Blake <eblake@redhat.com>

We generate a static visit_type_FOO_fields() for every type
FOO.  However, sometimes we need a forward declaration. Split
the code to generate the forward declaration out of
gen_visit_implicit_struct() into a new gen_visit_fields_decl(),
and also prepare for a forward declaration to be emitted
during gen_visit_struct(), so that a future patch can switch
from using visit_type_FOO_implicit() to the simpler
visit_type_FOO_fields() as part of unboxing the base class
of a struct.

No change to generated code.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1445898903-12082-8-git-send-email-eblake@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
---
 scripts/qapi-visit.py | 26 ++++++++++++++++++--------
 1 file changed, 18 insertions(+), 8 deletions(-)

diff --git a/scripts/qapi-visit.py b/scripts/qapi-visit.py
index 2dc3aed..d4408f2 100644
--- a/scripts/qapi-visit.py
+++ b/scripts/qapi-visit.py
@@ -15,7 +15,12 @@
 from qapi import *
 import re
 
+# visit_type_FOO_implicit() is emitted as needed; track if it has already
+# been output.
 implicit_structs_seen = set()
+
+# visit_type_FOO_fields() is always emitted; track if a forward declaration
+# or implementation has already been output.
 struct_fields_seen = set()
 
 
@@ -29,19 +34,24 @@ void visit_type_%(c_name)s(Visitor *v, %(c_type)sobj, const char *name, Error **
                  c_name=c_name(name), c_type=c_type)
 
 
+def gen_visit_fields_decl(typ):
+    ret = ''
+    if typ.name not in struct_fields_seen:
+        ret += mcgen('''
+
+static void visit_type_%(c_type)s_fields(Visitor *v, %(c_type)s **obj, Error **errp);
+''',
+                     c_type=typ.c_name())
+        struct_fields_seen.add(typ.name)
+    return ret
+
+
 def gen_visit_implicit_struct(typ):
     if typ in implicit_structs_seen:
         return ''
     implicit_structs_seen.add(typ)
 
-    ret = ''
-    if typ.name not in struct_fields_seen:
-        # Need a forward declaration
-        ret += mcgen('''
-
-static void visit_type_%(c_type)s_fields(Visitor *v, %(c_type)s **obj, Error **errp);
-''',
-                     c_type=typ.c_name())
+    ret = gen_visit_fields_decl(typ)
 
     ret += mcgen('''
 
-- 
2.4.3