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[Qemu-devel] [PATCH v11 06/15] qapi: Visit variants in visit_type_FOO_fi
From: |
Eric Blake |
Subject: |
[Qemu-devel] [PATCH v11 06/15] qapi: Visit variants in visit_type_FOO_fields() |
Date: |
Wed, 17 Feb 2016 23:48:20 -0700 |
We initially created the static visit_type_FOO_fields() helper
function for reuse of code - we have cases where the initial
setup for a visit has different allocation (depending on whether
the fields represent a stand-alone type or are embedded as part
of a larger type), but where the actual field visits are
identical once a pointer is available.
Up until the previous patch, visit_type_FOO_fields() was only
used for structs (no variants), so it was covering every field
for each type where it was emitted.
Meanwhile, the code for visiting unions looks like:
static visit_type_U_fields() {
visit base;
visit local_members;
}
visit_type_U() {
visit_start_struct();
visit_type_U_fields();
visit variants;
visit_end_struct();
}
which splits the fields of the union visit across two functions.
Move the code to visit variants to live inside visit_type_U_fields(),
while making it conditional on having variants so that all other
instances of the helper function remain unchanged. This is also
a step closer towards unifying struct and union visits, and towards
allowing one union type to be the branch of another flat union.
The resulting diff to the generated code is a bit hard to read,
but it can be verified that it touches only union types, and that
the end result is the following general structure:
static visit_type_U_fields() {
visit base;
visit local_members;
visit variants;
}
visit_type_U() {
visit_start_struct();
visit_type_U_fields();
visit_end_struct();
}
Signed-off-by: Eric Blake <address@hidden>
---
v11: new patch
---
scripts/qapi-visit.py | 104 +++++++++++++++++++++++++-------------------------
1 file changed, 53 insertions(+), 51 deletions(-)
diff --git a/scripts/qapi-visit.py b/scripts/qapi-visit.py
index 1051710..6cea7d6 100644
--- a/scripts/qapi-visit.py
+++ b/scripts/qapi-visit.py
@@ -71,11 +71,16 @@ static void visit_type_implicit_%(c_type)s(Visitor *v,
%(c_type)s **obj, Error *
return ret
-def gen_visit_struct_fields(name, base, members):
+def gen_visit_struct_fields(name, base, members, variants=None):
ret = ''
if base:
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_implicit_struct(var.type)
struct_fields_seen.add(name)
ret += mcgen('''
@@ -96,8 +101,49 @@ static void visit_type_%(c_name)s_fields(Visitor *v,
%(c_name)s **obj, Error **e
ret += gen_visit_fields(members, prefix='(*obj)->')
- # 'goto out' produced for base, and by gen_visit_fields() for each member
- if base or members:
+ if variants:
+ ret += mcgen('''
+ if (!visit_start_union(v, !!(*obj)->u.data, &err) || err) {
+ goto out;
+ }
+ switch ((*obj)->%(c_name)s) {
+''',
+ 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_implicit_%(c_type)s(v, &(*obj)->u.%(c_name)s, &err);
+''',
+ c_type=var.type.c_name(),
+ c_name=c_name(var.name))
+ ret += mcgen('''
+ break;
+''')
+
+ ret += mcgen('''
+ default:
+ abort();
+ }
+''')
+
+ # 'goto out' produced for base, by gen_visit_fields() for each member,
+ # and if variants were present
+ if base or members or variants:
ret += mcgen('''
out:
@@ -239,12 +285,7 @@ out:
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
- if not var.simple_union_type():
- ret += gen_visit_implicit_struct(var.type)
+ ret = gen_visit_struct_fields(name, base, members, variants)
ret += mcgen('''
@@ -260,54 +301,15 @@ void visit_type_%(c_name)s(Visitor *v, const char *name,
%(c_name)s **obj, Error
goto out_obj;
}
visit_type_%(c_name)s_fields(v, obj, &err);
-''',
- c_name=c_name(name))
- ret += gen_err_check(label='out_obj')
- ret += mcgen('''
- if (!visit_start_union(v, !!(*obj)->u.data, &err) || err) {
- goto out_obj;
- }
- switch ((*obj)->%(c_name)s) {
-''',
- 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_implicit_%(c_type)s(v, &(*obj)->u.%(c_name)s, &err);
-''',
- c_type=var.type.c_name(),
- c_name=c_name(var.name))
- ret += mcgen('''
- break;
-''')
-
- ret += mcgen('''
- default:
- abort();
- }
-out_obj:
error_propagate(errp, err);
err = NULL;
+out_obj:
visit_end_struct(v, &err);
out:
error_propagate(errp, err);
}
-''')
+''',
+ c_name=c_name(name))
return ret
--
2.5.0
- [Qemu-devel] [PATCH v11 02/15] qapi: Forbid empty unions and useless alternates, (continued)
[Qemu-devel] [PATCH v11 06/15] qapi: Visit variants in visit_type_FOO_fields(),
Eric Blake <=
[Qemu-devel] [PATCH v11 10/15] qapi: Emit structs used as variants in topological order, Eric Blake, 2016/02/18
[Qemu-devel] [PATCH v11 09/15] qapi: Adjust layout of FooList types, Eric Blake, 2016/02/18
[Qemu-devel] [PATCH v11 14/15] qapi: Delete visit_start_union(), gen_visit_implicit_struct(), Eric Blake, 2016/02/18