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qapi: Segregate anonymous unions into alternates in generator 

Special-casing 'discriminator == {}' for handling anonymous unions
is getting awkward; since this particular type is not always a
dictionary on the wire, it is easier to treat it as a completely
different class of type, "alternate", so that if a type is listed
in the union_types array, we know it is not an anonymous union.

This patch just further segregates union handling, to make sure that
anonymous unions are not stored in union_types, and splitting up
check_union() into separate functions.  A future patch will change
the qapi grammar, and having the segregation already in place will
make it easier to deal with the distinct meta-type.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
This commit is contained in:
Eric Blake 2015-05-04 09:05:10 -06:00 committed by Markus Armbruster
parent 268a1c5eb1
commit 811d04fd0c
5 changed files with 62 additions and 40 deletions
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6
scripts/qapi-types.py
View File

@ -170,7 +170,7 @@ typedef enum %(name)s
return lookup_decl + enum_decl
def generate_anon_union_qtypes(expr):
def generate_alternate_qtypes(expr):
name = expr['union']
members = expr['data']
@ -181,7 +181,7 @@ const int %(name)s_qtypes[QTYPE_MAX] = {
name=name)
for key in members:
qtype = find_anonymous_member_qtype(members[key])
qtype = find_alternate_member_qtype(members[key])
assert qtype, "Invalid anonymous union member"
ret += mcgen('''
@ -408,7 +408,7 @@ for expr in exprs:
fdef.write(generate_enum_lookup('%sKind' % expr['union'],
expr['data'].keys()))
if expr.get('discriminator') == {}:
fdef.write(generate_anon_union_qtypes(expr))
fdef.write(generate_alternate_qtypes(expr))
else:
continue
fdecl.write(ret)

4
scripts/qapi-visit.py
View File

@ -237,7 +237,7 @@ void visit_type_%(name)s(Visitor *m, %(name)s *obj, const char *name, Error **er
''',
name=name)
def generate_visit_anon_union(name, members):
def generate_visit_alternate(name, members):
ret = mcgen('''
void visit_type_%(name)s(Visitor *m, %(name)s **obj, const char *name, Error **errp)
@ -302,7 +302,7 @@ def generate_visit_union(expr):
if discriminator == {}:
assert not base
return generate_visit_anon_union(name, members)
return generate_visit_alternate(name, members)
enum_define = discriminator_find_enum_define(expr)
if enum_define:

88
scripts/qapi.py
View File

@ -224,21 +224,16 @@ def find_base_fields(base):
return None
return base_struct_define['data']
# Return the qtype of an anonymous union branch, or None on error.
def find_anonymous_member_qtype(qapi_type):
# Return the qtype of an alternate branch, or None on error.
def find_alternate_member_qtype(qapi_type):
if builtin_types.has_key(qapi_type):
return builtin_types[qapi_type]
elif find_struct(qapi_type):
return "QTYPE_QDICT"
elif find_enum(qapi_type):
return "QTYPE_QSTRING"
else:
union = find_union(qapi_type)
if union:
discriminator = union.get('discriminator')
if discriminator == {}:
return None
return "QTYPE_QDICT"
elif find_union(qapi_type):
return "QTYPE_QDICT"
return None
# Return the discriminator enum define if discriminator is specified as an
@ -276,7 +271,6 @@ def check_union(expr, expr_info):
discriminator = expr.get('discriminator')
members = expr['data']
values = { 'MAX': '(automatic)' }
types_seen = {}
# If the object has a member 'base', its value must name a complex type,
# and there must be a discriminator.
@ -286,13 +280,15 @@ def check_union(expr, expr_info):
"Union '%s' requires a discriminator to go "
"along with base" %name)
# If the union object has no member 'discriminator', it's a
# simple union. If 'discriminator' is {}, it is an anonymous union.
if discriminator is None or discriminator == {}:
# Two types of unions, determined by discriminator.
assert discriminator != {}
# With no discriminator it is a simple union.
if discriminator is None:
enum_define = None
if base is not None:
raise QAPIExprError(expr_info,
"Union '%s' must not have a base"
"Simple union '%s' must not have a base"
% name)
# Else, it's a flat union.
@ -347,24 +343,46 @@ def check_union(expr, expr_info):
% (name, key, values[c_key]))
values[c_key] = key
# Ensure anonymous unions have no type conflicts.
if discriminator == {}:
if isinstance(value, list):
raise QAPIExprError(expr_info,
"Anonymous union '%s' member '%s' must "
"not be array type" % (name, key))
qtype = find_anonymous_member_qtype(value)
if not qtype:
raise QAPIExprError(expr_info,
"Anonymous union '%s' member '%s' has "
"invalid type '%s'" % (name, key, value))
if qtype in types_seen:
raise QAPIExprError(expr_info,
"Anonymous union '%s' member '%s' can't "
"be distinguished from member '%s'"
% (name, key, types_seen[qtype]))
types_seen[qtype] = key
def check_alternate(expr, expr_info):
name = expr['union']
base = expr.get('base')
discriminator = expr.get('discriminator')
members = expr['data']
values = { 'MAX': '(automatic)' }
types_seen = {}
assert discriminator == {}
if base is not None:
raise QAPIExprError(expr_info,
"Anonymous union '%s' must not have a base"
% name)
# Check every branch
for (key, value) in members.items():
# Check for conflicts in the generated enum
c_key = _generate_enum_string(key)
if c_key in values:
raise QAPIExprError(expr_info,
"Anonymous union '%s' member '%s' clashes "
"with '%s'" % (name, key, values[c_key]))
values[c_key] = key
# Ensure alternates have no type conflicts.
if isinstance(value, list):
raise QAPIExprError(expr_info,
"Anonymous union '%s' member '%s' must "
"not be array type" % (name, key))
qtype = find_alternate_member_qtype(value)
if not qtype:
raise QAPIExprError(expr_info,
"Anonymous union '%s' member '%s' has "
"invalid type '%s'" % (name, key, value))
if qtype in types_seen:
raise QAPIExprError(expr_info,
"Anonymous union '%s' member '%s' can't "
"be distinguished from member '%s'"
% (name, key, types_seen[qtype]))
types_seen[qtype] = key
def check_enum(expr, expr_info):
name = expr['enum']
@ -394,7 +412,10 @@ def check_exprs(schema):
if expr.has_key('enum'):
check_enum(expr, info)
elif expr.has_key('union'):
check_union(expr, info)
if expr.get('discriminator') == {}:
check_alternate(expr, info)
else:
check_union(expr, info)
elif expr.has_key('event'):
check_event(expr, info)
@ -536,7 +557,8 @@ def find_struct(name):
def add_union(definition):
global union_types
union_types.append(definition)
if definition.get('discriminator') != {}:
union_types.append(definition)
def find_union(name):
global union_types

2
tests/qapi-schema/alternate-base.err
View File

@ -1 +1 @@
tests/qapi-schema/alternate-base.json:4: Union 'MyUnion' must not have a base
tests/qapi-schema/alternate-base.json:4: Anonymous union 'MyUnion' must not have a base

2
tests/qapi-schema/alternate-clash.err
View File

@ -1 +1 @@
tests/qapi-schema/alternate-clash.json:2: Union 'Union1' member 'ONE' clashes with 'one'
tests/qapi-schema/alternate-clash.json:2: Anonymous union 'Union1' member 'ONE' clashes with 'one'