Previously, working with alternates required two lookup arrays
and some indirection: for type Foo, we created Foo_qtypes[]
which maps each qtype to a value of the generated FooKind enum,
then look up that value in FooKind_lookup[] like we do for other
union types.
This has a couple of subtle bugs. First, the generator was
creating a call with a parameter '(int *) &(*obj)->type' where
type is an enum type; this is unsafe if the compiler chooses
to store the enum type in a different size than int, where
assigning through the wrong size pointer can corrupt data or
cause a SIGBUS.
Related bug, not not fixed in this patch: qapi-visit.py's
gen_visit_enum() generates a cast of its enum * argument to
int *. Marked FIXME.
Second, since the values of the FooKind enum start at zero, all
entries of the Foo_qtypes[] array that were not explicitly
initialized will map to the same branch of the union as the
first member of the alternate, rather than triggering a desired
failure in visit_get_next_type(). Fortunately, the bug seldom
bites; the very next thing the input visitor does is try to
parse the incoming JSON with the wrong parser, which normally
fails; the output visitor is not used with a C struct in that
state, and the dealloc visitor has nothing to clean up (so
there is no leak).
However, the second bug IS observable in one case: parsing an
integer causes unusual behavior in an alternate that contains
at least a 'number' member but no 'int' member, because the
'number' parser accepts QTYPE_QINT in addition to the expected
QTYPE_QFLOAT (that is, since 'int' is not a member, the type
QTYPE_QINT accidentally maps to FooKind 0; if this enum value
is the 'number' branch the integer parses successfully, but if
the 'number' branch is not first, some other branch tries to
parse the integer and rejects it). A later patch will worry
about fixing alternates to always parse all inputs that a
non-alternate 'number' would accept, for now this is still
marked FIXME in the updated test-qmp-input-visitor.c, to
merely point out that new undesired behavior of 'ans' matches
the existing undesired behavior of 'asn'.
This patch fixes the default-initialization bug by deleting the
indirection, and modifying get_next_type() to directly assign a
QTypeCode parameter. This in turn fixes the type-casting bug,
as we are no longer casting a pointer to enum to a questionable
size. There is no longer a need to generate an implicit FooKind
enum associated with the alternate type (since the QMP wire
format never uses the stringized counterparts of the C union
member names). Since the updated visit_get_next_type() does not
know which qtypes are expected, the generated visitor is
modified to generate an error statement if an unexpected type is
encountered.
Callers now have to know the QTYPE_* mapping when looking at the
discriminator; but so far, only the testsuite was even using the
C struct of an alternate types. I considered the possibility of
keeping the internal enum FooKind, but initialized differently
than most generated arrays, as in:
typedef enum FooKind {
FOO_KIND_A = QTYPE_QDICT,
FOO_KIND_B = QTYPE_QINT,
} FooKind;
to create nicer aliases for knowing when to use foo->a or foo->b
when inspecting foo->type; but it turned out to add too much
complexity, especially without a client.
There is a user-visible side effect to this change, but I
consider it to be an improvement. Previously,
the invalid QMP command:
{"execute":"blockdev-add", "arguments":{"options":
{"driver":"raw", "id":"a", "file":true}}}
failed with:
{"error": {"class": "GenericError",
"desc": "Invalid parameter type for 'file', expected: QDict"}}
(visit_get_next_type() succeeded, and the error comes from the
visit_type_BlockdevOptions() expecting {}; there is no mention of
the fact that a string would also work). Now it fails with:
{"error": {"class": "GenericError",
"desc": "Invalid parameter type for 'file', expected: BlockdevRef"}}
(the error when the next type doesn't match any expected types for
the overall alternate).
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <
1449033659-25497-5-git-send-email-eblake@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
'data': { 'definition': 'BlockdevOptions',
'reference': 'str' } }
-Just like for a simple union, an implicit C enum 'NameKind' is created
-to enumerate the branches for the alternate 'Name'.
-
Unlike a union, the discriminator string is never passed on the wire
for the Client JSON Protocol. Instead, the value's JSON type serves
as an implicit discriminator, which in turn means that an alternate
void (*type_enum)(Visitor *v, int *obj, const char * const strings[],
const char *kind, const char *name, Error **errp);
- void (*get_next_type)(Visitor *v, int *kind, const int *qobjects,
+ /* May be NULL; only needed for input visitors. */
+ void (*get_next_type)(Visitor *v, QType *type,
const char *name, Error **errp);
void (*type_int)(Visitor *v, int64_t *obj, const char *name, Error **errp);
void visit_end_list(Visitor *v, Error **errp);
void visit_optional(Visitor *v, bool *present, const char *name,
Error **errp);
-void visit_get_next_type(Visitor *v, int *obj, const int *qtypes,
+
+/**
+ * Determine the qtype of the item @name in the current object visit.
+ * For input visitors, set *@type to the correct qtype of a qapi
+ * alternate type; for other visitors, leave *@type unchanged.
+ */
+void visit_get_next_type(Visitor *v, QType *type,
const char *name, Error **errp);
void visit_type_enum(Visitor *v, int *obj, const char * const strings[],
const char *kind, const char *name, Error **errp);
}
}
-void visit_get_next_type(Visitor *v, int *obj, const int *qtypes,
+void visit_get_next_type(Visitor *v, QType *type,
const char *name, Error **errp)
{
if (v->get_next_type) {
- v->get_next_type(v, obj, qtypes, name, errp);
+ v->get_next_type(v, type, name, errp);
}
}
qmp_input_pop(qiv, errp);
}
-static void qmp_input_get_next_type(Visitor *v, int *kind, const int *qobjects,
+static void qmp_input_get_next_type(Visitor *v, QType *type,
const char *name, Error **errp)
{
QmpInputVisitor *qiv = to_qiv(v);
error_setg(errp, QERR_MISSING_PARAMETER, name ? name : "null");
return;
}
- *kind = qobjects[qobject_type(qobj)];
+ *type = qobject_type(qobj);
}
static void qmp_input_type_int(Visitor *v, int64_t *obj, const char *name,
c_name=c_name(name), base=base.c_name())
-def gen_alternate_qtypes_decl(name):
- return mcgen('''
-
-extern const int %(c_name)s_qtypes[];
-''',
- c_name=c_name(name))
-
-
-def gen_alternate_qtypes(name, variants):
- ret = mcgen('''
-
-const int %(c_name)s_qtypes[QTYPE__MAX] = {
-''',
- c_name=c_name(name))
-
- for var in variants.variants:
- qtype = var.type.alternate_qtype()
- assert qtype
-
- ret += mcgen('''
- [%(qtype)s] = %(enum_const)s,
-''',
- qtype=qtype,
- enum_const=c_enum_const(variants.tag_member.type.name,
- var.name))
-
- ret += mcgen('''
-};
-''')
- return ret
-
-
def gen_variants(variants):
# FIXME: What purpose does data serve, besides preventing a union that
# has a branch named 'data'? We use it in qapi-visit.py to decide
def visit_alternate_type(self, name, info, variants):
self._fwdecl += gen_fwd_object_or_array(name)
- self._fwdefn += gen_alternate_qtypes(name, variants)
self.decl += gen_object(name, None, [variants.tag_member], variants)
- self.decl += gen_alternate_qtypes_decl(name)
self._gen_type_cleanup(name)
# If you link code generated from multiple schemata, you want only one
def gen_visit_enum(name):
+ # FIXME cast from enum *obj to int * invalidly assumes enum is int
return mcgen('''
void visit_type_%(c_name)s(Visitor *v, %(c_name)s *obj, const char *name, Error **errp)
if (err) {
goto out;
}
- visit_get_next_type(v, (int*) &(*obj)->type, %(c_name)s_qtypes, name, &err);
+ visit_get_next_type(v, &(*obj)->type, name, &err);
if (err) {
goto out_obj;
}
''',
c_name=c_name(name))
+ # FIXME: When 'number' but not 'int' is present in the alternate, we
+ # should allow QTYPE_INT to promote to QTYPE_FLOAT.
for var in variants.variants:
ret += mcgen('''
case %(case)s:
visit_type_%(c_type)s(v, &(*obj)->u.%(c_name)s, name, &err);
break;
''',
- case=c_enum_const(variants.tag_member.type.name,
- var.name),
+ case=var.type.alternate_qtype(),
c_type=var.type.c_name(),
c_name=c_name(var.name))
ret += mcgen('''
default:
- abort();
+ error_setg(&err, QERR_INVALID_PARAMETER_TYPE, name ? name : "null",
+ "%(name)s");
}
out_obj:
error_propagate(errp, err);
out:
error_propagate(errp, err);
}
-''')
+''',
+ name=name)
return ret
fdecl.write(mcgen('''
#include "qapi/visitor.h"
+#include "qapi/qmp/qerror.h"
#include "%(prefix)sqapi-types.h"
''',
for (key, value) in members.items():
check_name(expr_info, "Member of alternate '%s'" % name, key)
- # Check for conflicts in the generated enum
- c_key = camel_to_upper(key)
+ # Check for conflicts in the branch names
+ c_key = c_name(key)
if c_key in values:
raise QAPIExprError(expr_info,
"Alternate '%s' member '%s' clashes with '%s'"
assert isinstance(self.tag_member.type, QAPISchemaEnumType)
for v in self.variants:
v.check(schema)
- assert v.name in self.tag_member.type.values
- if isinstance(v.type, QAPISchemaObjectType):
+ # Union names must match enum values; alternate names are
+ # checked separately. Use 'seen' to tell the two apart.
+ if seen:
+ assert v.name in self.tag_member.type.values
+ assert isinstance(v.type, QAPISchemaObjectType)
v.type.check(schema)
def check_clash(self, schema, info, seen):
# Not calling self.variants.check_clash(), because there's nothing
# to clash with
self.variants.check(schema, {})
+ # Alternate branch names have no relation to the tag enum values;
+ # so we have to check for potential name collisions ourselves.
+ seen = {}
+ for v in self.variants.variants:
+ v.check_clash(self.info, seen)
def json_type(self):
return 'value'
data = expr['data']
variants = [self._make_variant(key, value)
for (key, value) in data.iteritems()]
- tag_member = self._make_implicit_tag(name, info, variants)
+ tag_member = QAPISchemaObjectTypeMember('type', 'QType', False)
self._def_entity(
QAPISchemaAlternateType(name, info,
QAPISchemaObjectTypeVariants(None,
object :empty
alternate Alt
case i: int
-enum AltKind ['i']
enum QType ['none', 'qnull', 'qint', 'qstring', 'qdict', 'qlist', 'qfloat', 'qbool']
prefix QTYPE
alternate AltIntNum
case i: int
case n: number
-enum AltIntNumKind ['i', 'n']
alternate AltNumInt
case n: number
case i: int
-enum AltNumIntKind ['n', 'i']
alternate AltNumStr
case n: number
case s: str
-enum AltNumStrKind ['n', 's']
alternate AltStrBool
case s: str
case b: bool
-enum AltStrBoolKind ['s', 'b']
alternate AltStrInt
case s: str
case i: int
-enum AltStrIntKind ['s', 'i']
alternate AltStrNum
case s: str
case n: number
-enum AltStrNumKind ['s', 'n']
event EVENT_A None
event EVENT_B None
event EVENT_C :obj-EVENT_C-arg
case uda: UserDefA
case s: str
case i: int
-enum UserDefAlternateKind ['uda', 's', 'i']
object UserDefB
member intb: int optional=False
member a-b: bool optional=True
alternate __org.qemu_x-Alt
case __org.qemu_x-branch: str
case b: __org.qemu_x-Base
-enum __org.qemu_x-AltKind ['__org.qemu_x-branch', 'b']
object __org.qemu_x-Base
member __org.qemu_x-member1: __org.qemu_x-Enum optional=False
enum __org.qemu_x-Enum ['__org.qemu_x-value']
v = visitor_input_test_init(data, "42");
visit_type_UserDefAlternate(v, &tmp, NULL, &error_abort);
- g_assert_cmpint(tmp->type, ==, USER_DEF_ALTERNATE_KIND_I);
+ g_assert_cmpint(tmp->type, ==, QTYPE_QINT);
g_assert_cmpint(tmp->u.i, ==, 42);
qapi_free_UserDefAlternate(tmp);
v = visitor_input_test_init(data, "'string'");
visit_type_UserDefAlternate(v, &tmp, NULL, &error_abort);
- g_assert_cmpint(tmp->type, ==, USER_DEF_ALTERNATE_KIND_S);
+ g_assert_cmpint(tmp->type, ==, QTYPE_QSTRING);
g_assert_cmpstr(tmp->u.s, ==, "string");
qapi_free_UserDefAlternate(tmp);
error_free_or_abort(&err);
qapi_free_AltStrBool(asb);
- /* FIXME: Order of alternate should not affect semantics; asn should
- * parse the same as ans */
+ /* FIXME: integer should parse as number */
v = visitor_input_test_init(data, "42");
visit_type_AltStrNum(v, &asn, NULL, &err);
- /* FIXME g_assert_cmpint(asn->type, == ALT_STR_NUM_KIND_N); */
+ /* FIXME g_assert_cmpint(asn->type, ==, QTYPE_QFLOAT); */
/* FIXME g_assert_cmpfloat(asn->u.n, ==, 42); */
error_free_or_abort(&err);
qapi_free_AltStrNum(asn);
+ /* FIXME: integer should parse as number */
v = visitor_input_test_init(data, "42");
- visit_type_AltNumStr(v, &ans, NULL, &error_abort);
- g_assert_cmpint(ans->type, ==, ALT_NUM_STR_KIND_N);
- g_assert_cmpfloat(ans->u.n, ==, 42);
+ visit_type_AltNumStr(v, &ans, NULL, &err);
+ /* FIXME g_assert_cmpint(ans->type, ==, QTYPE_QFLOAT); */
+ /* FIXME g_assert_cmpfloat(ans->u.n, ==, 42); */
+ error_free_or_abort(&err);
qapi_free_AltNumStr(ans);
v = visitor_input_test_init(data, "42");
visit_type_AltStrInt(v, &asi, NULL, &error_abort);
- g_assert_cmpint(asi->type, ==, ALT_STR_INT_KIND_I);
+ g_assert_cmpint(asi->type, ==, QTYPE_QINT);
g_assert_cmpint(asi->u.i, ==, 42);
qapi_free_AltStrInt(asi);
v = visitor_input_test_init(data, "42");
visit_type_AltIntNum(v, &ain, NULL, &error_abort);
- g_assert_cmpint(ain->type, ==, ALT_INT_NUM_KIND_I);
+ g_assert_cmpint(ain->type, ==, QTYPE_QINT);
g_assert_cmpint(ain->u.i, ==, 42);
qapi_free_AltIntNum(ain);
v = visitor_input_test_init(data, "42");
visit_type_AltNumInt(v, &ani, NULL, &error_abort);
- g_assert_cmpint(ani->type, ==, ALT_NUM_INT_KIND_I);
+ g_assert_cmpint(ani->type, ==, QTYPE_QINT);
g_assert_cmpint(ani->u.i, ==, 42);
qapi_free_AltNumInt(ani);
v = visitor_input_test_init(data, "42.5");
visit_type_AltStrNum(v, &asn, NULL, &error_abort);
- g_assert_cmpint(asn->type, ==, ALT_STR_NUM_KIND_N);
+ g_assert_cmpint(asn->type, ==, QTYPE_QFLOAT);
g_assert_cmpfloat(asn->u.n, ==, 42.5);
qapi_free_AltStrNum(asn);
v = visitor_input_test_init(data, "42.5");
visit_type_AltNumStr(v, &ans, NULL, &error_abort);
- g_assert_cmpint(ans->type, ==, ALT_NUM_STR_KIND_N);
+ g_assert_cmpint(ans->type, ==, QTYPE_QFLOAT);
g_assert_cmpfloat(ans->u.n, ==, 42.5);
qapi_free_AltNumStr(ans);
v = visitor_input_test_init(data, "42.5");
visit_type_AltIntNum(v, &ain, NULL, &error_abort);
- g_assert_cmpint(ain->type, ==, ALT_INT_NUM_KIND_N);
+ g_assert_cmpint(ain->type, ==, QTYPE_QFLOAT);
g_assert_cmpfloat(ain->u.n, ==, 42.5);
qapi_free_AltIntNum(ain);
v = visitor_input_test_init(data, "42.5");
visit_type_AltNumInt(v, &ani, NULL, &error_abort);
- g_assert_cmpint(ani->type, ==, ALT_NUM_INT_KIND_N);
+ g_assert_cmpint(ani->type, ==, QTYPE_QFLOAT);
g_assert_cmpfloat(ani->u.n, ==, 42.5);
qapi_free_AltNumInt(ani);
}
UserDefAlternate *tmp;
tmp = g_new0(UserDefAlternate, 1);
- tmp->type = USER_DEF_ALTERNATE_KIND_I;
+ tmp->type = QTYPE_QINT;
tmp->u.i = 42;
visit_type_UserDefAlternate(data->ov, &tmp, NULL, &error_abort);
qobject_decref(arg);
tmp = g_new0(UserDefAlternate, 1);
- tmp->type = USER_DEF_ALTERNATE_KIND_S;
+ tmp->type = QTYPE_QSTRING;
tmp->u.s = g_strdup("hello");
visit_type_UserDefAlternate(data->ov, &tmp, NULL, &error_abort);
projects / people / liuw / qemu.git / commitdiff