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authorMarkus Armbruster <armbru@redhat.com>2015-06-28 20:05:53 +0200
committerMarkus Armbruster <armbru@redhat.com>2015-09-04 15:47:13 +0200
commit1e6c1616a91cdcbe9a8387541f7689b8c11632aa (patch)
tree077667234523416e849d7f185a6b77edaee0864c
parent0f61af3eb396ae163cd1572ce12e05f5d08d7c15 (diff)
qapi: Generate a nicer struct for flat unions
The struct generated for a flat union is weird: the members of its base are at the end, except for the union tag, which is at the beginning. Example: qapi-schema-test.json has { 'struct': 'UserDefUnionBase', 'data': { 'string': 'str', 'enum1': 'EnumOne' } } { 'union': 'UserDefFlatUnion', 'base': 'UserDefUnionBase', 'discriminator': 'enum1', 'data': { 'value1' : 'UserDefA', 'value2' : 'UserDefB', 'value3' : 'UserDefB' } } We generate: struct UserDefFlatUnion { EnumOne enum1; union { void *data; UserDefA *value1; UserDefB *value2; UserDefB *value3; }; char *string; }; Change to put all base members at the beginning, unadulterated. Not only is this easier to understand, it also permits casting the flat union to its base, if that should become useful. We now generate: struct UserDefFlatUnion { /* Members inherited from UserDefUnionBase: */ char *string; EnumOne enum1; /* Own members: */ union { /* union tag is @enum1 */ void *data; UserDefA *value1; UserDefB *value2; UserDefB *value3; }; }; Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
-rw-r--r--scripts/qapi-types.py38
1 files changed, 22 insertions, 16 deletions
diff --git a/scripts/qapi-types.py b/scripts/qapi-types.py
index ac8dad3171..82141cdec3 100644
--- a/scripts/qapi-types.py
+++ b/scripts/qapi-types.py
@@ -200,13 +200,30 @@ def generate_union(expr, meta):
ret = mcgen('''
struct %(name)s
{
- %(discriminator_type_name)s %(discriminator)s;
- union {
+''',
+ name=name)
+ if base:
+ ret += mcgen('''
+ /* Members inherited from %(c_name)s: */
+''',
+ c_name=c_name(base))
+ base_fields = find_struct(base)['data']
+ ret += generate_struct_fields(base_fields)
+ ret += mcgen('''
+ /* Own members: */
+''')
+ else:
+ assert not discriminator
+ ret += mcgen('''
+ %(discriminator_type_name)s kind;
+''',
+ discriminator_type_name=c_name(discriminator_type_name))
+
+ ret += mcgen('''
+ union { /* union tag is @%(c_name)s */
void *data;
''',
- name=name,
- discriminator=c_name(discriminator or 'kind'),
- discriminator_type_name=c_name(discriminator_type_name))
+ c_name=c_name(discriminator or 'kind'))
for key in typeinfo:
ret += mcgen('''
@@ -217,17 +234,6 @@ struct %(name)s
ret += mcgen('''
};
-''')
-
- if base:
- assert discriminator
- base_fields = find_struct(base)['data'].copy()
- del base_fields[discriminator]
- ret += generate_struct_fields(base_fields)
- else:
- assert not discriminator
-
- ret += mcgen('''
};
''')
if meta == 'alternate':