0426d53c65
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>
205 lines
6.8 KiB
Plaintext
205 lines
6.8 KiB
Plaintext
object :empty
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object :obj-EVENT_C-arg
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member a: int optional=True
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member b: UserDefOne optional=True
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member c: str optional=False
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object :obj-EVENT_D-arg
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member a: EventStructOne optional=False
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member b: str optional=False
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member c: str optional=True
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member enum3: EnumOne optional=True
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object :obj-__org.qemu_x-command-arg
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member a: __org.qemu_x-EnumList optional=False
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member b: __org.qemu_x-StructList optional=False
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member c: __org.qemu_x-Union2 optional=False
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member d: __org.qemu_x-Alt optional=False
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object :obj-anyList-wrapper
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member data: anyList optional=False
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object :obj-boolList-wrapper
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member data: boolList optional=False
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object :obj-guest-get-time-arg
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member a: int optional=False
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member b: int optional=True
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object :obj-guest-sync-arg
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member arg: any optional=False
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object :obj-int16List-wrapper
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member data: int16List optional=False
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object :obj-int32List-wrapper
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member data: int32List optional=False
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object :obj-int64List-wrapper
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member data: int64List optional=False
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object :obj-int8List-wrapper
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member data: int8List optional=False
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object :obj-intList-wrapper
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member data: intList optional=False
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object :obj-numberList-wrapper
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member data: numberList optional=False
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object :obj-sizeList-wrapper
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member data: sizeList optional=False
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object :obj-str-wrapper
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member data: str optional=False
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object :obj-strList-wrapper
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member data: strList optional=False
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object :obj-uint16List-wrapper
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member data: uint16List optional=False
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object :obj-uint32List-wrapper
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member data: uint32List optional=False
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object :obj-uint64List-wrapper
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member data: uint64List optional=False
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object :obj-uint8List-wrapper
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member data: uint8List optional=False
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object :obj-user_def_cmd1-arg
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member ud1a: UserDefOne optional=False
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object :obj-user_def_cmd2-arg
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member ud1a: UserDefOne optional=False
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member ud1b: UserDefOne optional=True
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alternate AltIntNum
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case i: int
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case n: number
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alternate AltNumInt
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case n: number
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case i: int
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alternate AltNumStr
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case n: number
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case s: str
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alternate AltStrBool
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case s: str
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case b: bool
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alternate AltStrInt
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case s: str
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case i: int
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alternate AltStrNum
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case s: str
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case n: number
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event EVENT_A None
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event EVENT_B None
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event EVENT_C :obj-EVENT_C-arg
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event EVENT_D :obj-EVENT_D-arg
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object Empty1
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object Empty2
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base Empty1
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enum EnumOne ['value1', 'value2', 'value3']
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object EventStructOne
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member struct1: UserDefOne optional=False
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member string: str optional=False
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member enum2: EnumOne optional=True
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object ForceArrays
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member unused1: UserDefOneList optional=False
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member unused2: UserDefTwoList optional=False
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member unused3: TestStructList optional=False
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enum MyEnum []
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object NestedEnumsOne
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member enum1: EnumOne optional=False
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member enum2: EnumOne optional=True
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member enum3: EnumOne optional=False
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member enum4: EnumOne optional=True
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enum QEnumTwo ['value1', 'value2']
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prefix QENUM_TWO
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enum QType ['none', 'qnull', 'qint', 'qstring', 'qdict', 'qlist', 'qfloat', 'qbool']
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prefix QTYPE
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object TestStruct
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member integer: int optional=False
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member boolean: bool optional=False
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member string: str optional=False
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object UserDefA
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member boolean: bool optional=False
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member a_b: int optional=True
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alternate UserDefAlternate
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case uda: UserDefA
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case s: str
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case i: int
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object UserDefB
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member intb: int optional=False
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member a-b: bool optional=True
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object UserDefC
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member string1: str optional=False
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member string2: str optional=False
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object UserDefFlatUnion
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base UserDefUnionBase
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tag enum1
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case value1: UserDefA
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case value2: UserDefB
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case value3: UserDefB
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object UserDefFlatUnion2
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base UserDefUnionBase
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tag enum1
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case value1: UserDefC
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case value2: UserDefB
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case value3: UserDefA
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object UserDefNativeListUnion
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member type: UserDefNativeListUnionKind optional=False
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case integer: :obj-intList-wrapper
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case s8: :obj-int8List-wrapper
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case s16: :obj-int16List-wrapper
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case s32: :obj-int32List-wrapper
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case s64: :obj-int64List-wrapper
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case u8: :obj-uint8List-wrapper
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case u16: :obj-uint16List-wrapper
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case u32: :obj-uint32List-wrapper
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case u64: :obj-uint64List-wrapper
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case number: :obj-numberList-wrapper
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case boolean: :obj-boolList-wrapper
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case string: :obj-strList-wrapper
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case sizes: :obj-sizeList-wrapper
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case any: :obj-anyList-wrapper
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enum UserDefNativeListUnionKind ['integer', 's8', 's16', 's32', 's64', 'u8', 'u16', 'u32', 'u64', 'number', 'boolean', 'string', 'sizes', 'any']
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object UserDefOne
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base UserDefZero
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member string: str optional=False
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member enum1: EnumOne optional=True
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object UserDefOptions
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member i64: intList optional=True
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member u64: uint64List optional=True
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member u16: uint16List optional=True
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member i64x: int optional=True
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member u64x: uint64 optional=True
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object UserDefTwo
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member string0: str optional=False
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member dict1: UserDefTwoDict optional=False
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object UserDefTwoDict
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member string1: str optional=False
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member dict2: UserDefTwoDictDict optional=False
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member dict3: UserDefTwoDictDict optional=True
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object UserDefTwoDictDict
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member userdef: UserDefOne optional=False
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member string: str optional=False
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object UserDefUnionBase
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base UserDefZero
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member string: str optional=False
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member enum1: EnumOne optional=False
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object UserDefZero
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member integer: int optional=False
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event __ORG.QEMU_X-EVENT __org.qemu_x-Struct
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alternate __org.qemu_x-Alt
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case __org.qemu_x-branch: str
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case b: __org.qemu_x-Base
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object __org.qemu_x-Base
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member __org.qemu_x-member1: __org.qemu_x-Enum optional=False
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enum __org.qemu_x-Enum ['__org.qemu_x-value']
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object __org.qemu_x-Struct
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base __org.qemu_x-Base
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member __org.qemu_x-member2: str optional=False
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member wchar-t: int optional=True
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object __org.qemu_x-Struct2
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member array: __org.qemu_x-Union1List optional=False
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object __org.qemu_x-Union1
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member type: __org.qemu_x-Union1Kind optional=False
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case __org.qemu_x-branch: :obj-str-wrapper
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enum __org.qemu_x-Union1Kind ['__org.qemu_x-branch']
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object __org.qemu_x-Union2
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base __org.qemu_x-Base
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tag __org.qemu_x-member1
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case __org.qemu_x-value: __org.qemu_x-Struct2
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command __org.qemu_x-command :obj-__org.qemu_x-command-arg -> __org.qemu_x-Union1
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gen=True success_response=True
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command guest-get-time :obj-guest-get-time-arg -> int
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gen=True success_response=True
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command guest-sync :obj-guest-sync-arg -> any
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gen=True success_response=True
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command user_def_cmd None -> None
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gen=True success_response=True
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command user_def_cmd1 :obj-user_def_cmd1-arg -> None
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gen=True success_response=True
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command user_def_cmd2 :obj-user_def_cmd2-arg -> UserDefTwo
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gen=True success_response=True
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