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[Qemu-devel] [PATCH 1/3] qapi-visit: Simplify how we visit common union
From: |
Markus Armbruster |
Subject: |
[Qemu-devel] [PATCH 1/3] qapi-visit: Simplify how we visit common union members |
Date: |
Wed, 27 Jan 2016 14:54:46 +0100 |
For a simple union SU, gen_visit_union() generates a visit of its
single tag member, like this:
visit_type_SUKind(v, "type", &(*obj)->type, &err);
For a flat union FU with base B, it generates a visit of its base
fields:
visit_type_B_fields(v, (B **)obj, &err);
Instead, we can simply visit the common members using the same fields
visit function we use for structs, generated with
gen_visit_struct_fields(). This function visits the base if any, then
the local members.
For a simple union SU, visit_type_SU_fields() contains exactly the old
tag member visit, because there is no base, and the tag member is the
only member. For instance, the code generated for
qapi-schema-test.json's UserDefNativeListUnion changes like this:
@@ -740,6 +766,19 @@ out:
error_propagate(errp, err);
}
+static void visit_type_UserDefNativeListUnion_fields(Visitor *v,
UserDefNativeListUnion **obj, Error **errp)
+{
+ Error *err = NULL;
+
+ visit_type_UserDefNativeListUnionKind(v, "type", &(*obj)->type, &err);
+ if (err) {
+ goto out;
+ }
+
+out:
+ error_propagate(errp, err);
+}
+
void visit_type_UserDefNativeListUnion(Visitor *v, const char *name,
UserDefNativeListUnion **obj, Error **errp)
{
Error *err = NULL;
@@ -751,7 +790,7 @@ void visit_type_UserDefNativeListUnion(V
if (!*obj) {
goto out_obj;
}
- visit_type_UserDefNativeListUnionKind(v, "type", &(*obj)->type, &err);
+ visit_type_UserDefNativeListUnion_fields(v, obj, &err);
if (err) {
goto out_obj;
}
For a flat union FU, visit_type_FU_fields() contains exactly the old
base fields visit, because there is a base, but no members. For
instance, the code generated for qapi-schema-test.json's
UserDefFlatUnion changes like this:
@@ -616,6 +616,19 @@ out:
static void visit_type_UserDefUnionBase_fields(Visitor *v,
UserDefUnionBase **obj, Error **errp);
+static void visit_type_UserDefFlatUnion_fields(Visitor *v,
UserDefFlatUnion **obj, Error **errp)
+{
+ Error *err = NULL;
+
+ visit_type_UserDefUnionBase_fields(v, (UserDefUnionBase **)obj, &err);
+ if (err) {
+ goto out;
+ }
+
+out:
+ error_propagate(errp, err);
+}
+
static void visit_type_implicit_UserDefA(Visitor *v, UserDefA **obj, Error
**errp)
{
Error *err = NULL;
@@ -651,7 +664,7 @@ void visit_type_UserDefFlatUnion(Visitor
if (!*obj) {
goto out_obj;
}
- visit_type_UserDefUnionBase_fields(v, (UserDefUnionBase **)obj, &err);
+ visit_type_UserDefFlatUnion_fields(v, obj, &err);
if (err) {
goto out_obj;
}
As you see, the generated code grows a bit, but in practice, it's lost
in the noise: qapi-schema.json's qapi-visit.c gains roughly 1%.
This simplification became possible with commit 441cbac "qapi-visit:
Convert to QAPISchemaVisitor, fixing bugs". It's a step towards
unifying gen_struct() and gen_union().
Signed-off-by: Markus Armbruster <address@hidden>
---
scripts/qapi-visit.py | 27 ++++-----------------------
1 file changed, 4 insertions(+), 23 deletions(-)
diff --git a/scripts/qapi-visit.py b/scripts/qapi-visit.py
index 573bb81..5c0d4d2 100644
--- a/scripts/qapi-visit.py
+++ b/scripts/qapi-visit.py
@@ -238,11 +238,8 @@ out:
return ret
-def gen_visit_union(name, base, variants):
- ret = ''
-
- if base:
- ret += gen_visit_fields_decl(base)
+def gen_visit_union(name, base, members, variants):
+ ret = gen_visit_struct_fields(name, base, members)
for var in variants.variants:
# Ugly special case for simple union TODO get rid of it
@@ -262,21 +259,9 @@ void visit_type_%(c_name)s(Visitor *v, const char *name,
%(c_name)s **obj, Error
if (!*obj) {
goto out_obj;
}
+ visit_type_%(c_name)s_fields(v, obj, &err);
''',
c_name=c_name(name))
-
- if base:
- ret += mcgen('''
- visit_type_%(c_name)s_fields(v, (%(c_name)s **)obj, &err);
-''',
- c_name=base.c_name())
- else:
- ret += mcgen('''
- visit_type_%(c_type)s(v, "%(name)s", &(*obj)->%(c_name)s, &err);
-''',
- c_type=variants.tag_member.type.c_name(),
- c_name=c_name(variants.tag_member.name),
- name=variants.tag_member.name)
ret += gen_err_check(label='out_obj')
ret += mcgen('''
if (!visit_start_union(v, !!(*obj)->u.data, &err) || err) {
@@ -381,11 +366,7 @@ class QAPISchemaGenVisitVisitor(QAPISchemaVisitor):
def visit_object_type(self, name, info, base, members, variants):
self.decl += gen_visit_decl(name)
if variants:
- if members:
- # Members other than variants.tag_member not implemented
- assert len(members) == 1
- assert members[0] == variants.tag_member
- self.defn += gen_visit_union(name, base, variants)
+ self.defn += gen_visit_union(name, base, members, variants)
else:
self.defn += gen_visit_struct(name, base, members)
--
2.4.3
[Qemu-devel] [PATCH 0/3] qapi-visit: Unify struct and union visit, Markus Armbruster, 2016/01/27
[Qemu-devel] [PATCH 3/3] qapi-visit: Unify struct and union visit, Markus Armbruster, 2016/01/27
[Qemu-devel] [PATCH 2/3] qapi-visit: Clean up code generated around visit_end_union(), Markus Armbruster, 2016/01/27
Re: [Qemu-devel] [PATCH 2/3] qapi-visit: Clean up code generated around visit_end_union(), Eric Blake, 2016/01/27
Re: [Qemu-devel] [PATCH 2/3] qapi-visit: Clean up code generated around visit_end_union(), Markus Armbruster, 2016/01/27
[Qemu-devel] [PATCH v9 18/37] qapi: Drop unused error argument for list and implicit struct, Eric Blake, 2016/01/19
[Qemu-devel] [PATCH v9 17/37] qapi: Drop unused 'kind' for struct/enum visit, Eric Blake, 2016/01/19