jcs.org
qemu with hax to log dma reads & writes
jcs.org/2018/11/12/vfio
qapi: Permit alternates with just one branch
A union or alternate without branches makes no sense and doesn't work:
it can't be instantiated. A union or alternate with just one branch
works, but is degenerate. We accept the former, but reject the
latter. Weird. docs/devel/qapi-code-gen.txt doesn't mention the
difference. It claims an alternate definition is "is similar to a
simple union type".
Permit degenerate alternates to make them consistent with unions.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20190913201349.24332-10-armbru@redhat.com>
+12
-10
+2
-4
scripts/qapi/common.py
+2
-4
scripts/qapi/common.py
···
920
920
members = expr['data']
921
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types_seen = {}
922
922
923
-
# Check every branch; require at least two branches
924
-
if len(members) < 2:
923
+
if len(members) == 0:
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raise QAPISemError(info,
926
-
"Alternate '%s' should have at least two branches "
927
-
"in 'data'" % name)
925
+
"Alternate '%s' cannot have empty 'data'" % name)
928
926
for (key, value) in members.items():
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check_name(info, "Member of alternate '%s'" % name, key)
930
928
check_known_keys(info,
+1
-1
tests/qapi-schema/alternate-empty.err
+1
-1
tests/qapi-schema/alternate-empty.err
+2
-2
tests/qapi-schema/alternate-empty.json
+2
-2
tests/qapi-schema/alternate-empty.json
+3
-1
tests/qapi-schema/qapi-schema-test.json
+3
-1
tests/qapi-schema/qapi-schema-test.json
···
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# test that we correctly compile downstream extensions, as well as munge
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# ticklish names
189
+
# also test union and alternate with just one branch
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{ 'enum': '__org.qemu_x-Enum', 'data': [ '__org.qemu_x-value' ] }
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{ 'struct': '__org.qemu_x-Base',
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'data': { '__org.qemu_x-member1': '__org.qemu_x-Enum' } }
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{ 'struct': '__org.qemu_x-Struct', 'base': '__org.qemu_x-Base',
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'data': { '__org.qemu_x-member2': 'str', '*wchar-t': 'int' } }
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{ 'union': '__org.qemu_x-Union1', 'data': { '__org.qemu_x-branch': 'str' } }
196
+
{ 'alternate': '__org.qemu_x-Alt1', 'data': { '__org.qemu_x-branch': 'str' } }
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{ 'struct': '__org.qemu_x-Struct2',
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'data': { 'array': ['__org.qemu_x-Union1'] } }
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{ 'union': '__org.qemu_x-Union2', 'base': '__org.qemu_x-Base',
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'discriminator': '__org.qemu_x-member1',
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'data': { '__org.qemu_x-value': '__org.qemu_x-Struct2' } }
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{ 'alternate': '__org.qemu_x-Alt',
201
-
'data': { '__org.qemu_x-branch': 'str', 'b': '__org.qemu_x-Base' } }
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+
'data': { '__org.qemu_x-branch': '__org.qemu_x-Base' } }
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{ 'event': '__ORG.QEMU_X-EVENT', 'data': '__org.qemu_x-Struct' }
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{ 'command': '__org.qemu_x-command',
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'data': { 'a': ['__org.qemu_x-Enum'], 'b': ['__org.qemu_x-Struct'],
+4
-2
tests/qapi-schema/qapi-schema-test.out
+4
-2
tests/qapi-schema/qapi-schema-test.out
···
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member type: __org.qemu_x-Union1Kind optional=False
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tag type
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case __org.qemu_x-branch: q_obj_str-wrapper
277
+
alternate __org.qemu_x-Alt1
278
+
tag type
279
+
case __org.qemu_x-branch: str
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array __org.qemu_x-Union1List __org.qemu_x-Union1
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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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case __org.qemu_x-value: __org.qemu_x-Struct2
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alternate __org.qemu_x-Alt
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tag type
286
-
case __org.qemu_x-branch: str
287
-
case b: __org.qemu_x-Base
289
+
case __org.qemu_x-branch: __org.qemu_x-Base
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event __ORG.QEMU_X-EVENT __org.qemu_x-Struct
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boxed=False
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array __org.qemu_x-EnumList __org.qemu_x-Enum