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authorEric Blake <eblake@redhat.com>2015-04-29 15:35:06 -0600
committerLuiz Capitulino <lcapitulino@redhat.com>2015-05-11 08:59:07 -0400
commite549e7161f37416ff66971d77d021d30057045ca (patch)
tree11199f2599532174c7fcb54641ed595786ffcc76 /qobject
parent481b002cc81ed7fc7b06e32e9d4d495d81739d14 (diff)
downloadqemu-arm-e549e7161f37416ff66971d77d021d30057045ca.tar.gz
json-parser: Accept 'null' in QMP
We document that in QMP, the client may send any json-value for the optional "id" key, and then return that same value on reply (both success and failures, insofar as the failure happened after parsing the id). [Note that the output may not be identical to the input, as whitespace may change and since we may reorder keys within a json-object, but that this still constitutes the same json-value]. However, we were not handling the JSON literal null, which counts as a json-value per RFC 7159. Also, down the road, given the QAPI schema of {'*foo':'str'} or {'*foo':'ComplexType'}, we could decide to allow the QMP client to pass { "foo":null } instead of the current representation of { } where omitting the key is the only way to get at the default NULL value. Such a change might be useful for argument introspection (if a type in older qemu lacks 'foo' altogether, then an explicit "foo":null probe will force an easily distinguished error message for whether the optional "foo" key is even understood in newer qemu). And if we add default values to optional arguments, allowing an explicit null would be required for getting a NULL value associated with an optional string that has a non-null default. But all that can come at a later day. The 'check-unit' testsuite is enhanced to test that parsing produces the same object as explicitly requesting a reference to the special qnull object. In addition, I tested with: $ ./x86_64-softmmu/qemu-system-x86_64 -qmp stdio -nodefaults {"QMP": {"version": {"qemu": {"micro": 91, "minor": 2, "major": 2}, "package": ""}, "capabilities": []}} {"execute":"qmp_capabilities","id":null} {"return": {}, "id": null} {"id":{"a":null,"b":[1,null]},"execute":"quit"} {"return": {}, "id": {"a": null, "b": [1, null]}} {"timestamp": {"seconds": 1427742379, "microseconds": 423128}, "event": "SHUTDOWN"} Signed-off-by: Eric Blake <eblake@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Diffstat (limited to 'qobject')
-rw-r--r--qobject/json-parser.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/qobject/json-parser.c b/qobject/json-parser.c
index 4288267bd3..717cb8fde7 100644
--- a/qobject/json-parser.c
+++ b/qobject/json-parser.c
@@ -561,6 +561,8 @@ static QObject *parse_keyword(JSONParserContext *ctxt)
ret = QOBJECT(qbool_from_int(true));
} else if (token_is_keyword(token, "false")) {
ret = QOBJECT(qbool_from_int(false));
+ } else if (token_is_keyword(token, "null")) {
+ ret = qnull();
} else {
parse_error(ctxt, token, "invalid keyword `%s'", token_get_value(token));
goto out;