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2020-12-19qobject: Factor JSON writer out of qobject_to_json()Markus Armbruster1-5/+0
We have two JSON writers written in C: qobject/qjson.c provides qobject_to_json(), and migration/qjson.c provides a more low level imperative interface. They don't share code. The latter tacitly limits numbers to int64_t, and strings contents to characters that don't need escaping. Factor out qobject_to_json()'s JSON writer as qobject/json-writer.c. Straightforward, except for numbers: since the writer is to be independent of QObject, it can't use qnum_to_string(). Open-code it instead. This is actually an improvement of sorts, because it liberates qnum_to_string() from JSON's needs: its JSON-related FIXMEs move to the JSON writer, where they belong. The next commit will replace migration/qjson.c. Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20201211171152.146877-16-armbru@redhat.com>
2020-12-19qobject: Move internals to qobject-internal.hMarkus Armbruster1-0/+1
Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20201211171152.146877-9-armbru@redhat.com>
2020-12-19qobject: Fix qnum_to_string() to use sufficient precisionMarkus Armbruster1-21/+3
We should serialize numbers to JSON so that they deserialize back to the same number. We fail to do so. The culprit is qnum_to_string(): it uses format %f with trailing '0' trimmed. Results in pretty output for "nice" numbers, but is prone to nasty rounding errors. For instance, numbers between 0 and 0.0000005 get flushed to zero. Where exactly the incorrect rounding can bite is tiresome to gauge. Here's my take. * In QMP output, type 'number': - query-blockstats value avg_rd_queue_depth - QMP query-migrate values mbps, cache-miss-rate, encoding-rate, busy-rate, compression-rate. Relatively harmless, I guess. * In tracing QMP input. Harmless. * In qemu-ga output, type 'number': guest-get-users value login-time. Harmless. * In output of HMP qom-get. Harmless. Not affected, because double values don't actually occur there (I think): * QMP output, type 'any': * qom-get value * qom-list, qom-list-properties value default-value * query-cpu-model-comparison, query-cpu-model-baseline, query-cpu-model-expansion value props. * qemu-img --output json output. * "json:" pseudo-filenames generated by bdrv_refresh_filename(). * The rbd block driver's "=keyvalue-pairs" hack. * In -object help on property default values. Aside: use of JSON feels inappropriate here. * Output of HMP qom-get. * Argument conversion to QemuOpts for qdev_device_add() and HMP with qemu_opts_from_qdict() QMP and HMP device_add, virtio-net failover primary creation, xen-usb "usb-host" creation, HMP netdev_add, object_add. * The uses of qobject_input_visitor_new_flat_confused() As far as I can tell, none of the visited types contain double values. * Dumping ImageInfoSpecific with dump_qobject() Fix by formatting with %.17g. 17 decimal digits always suffice for IEEE double. The change to expected test output illustrates the effect: the rounding errors are gone, but some seemingly "nice" numbers now get converted to not so nice strings, e.g. 0.42 to "0.41999999999999998". This is because 0.42 is not representable exactly in double. It's more accurate in this example than strictly necessary, though. If ugly accuracy bothers us, we can we can try using the least number of digits that still converts back to the same double. In this example, "0.42" would do. Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20201210161452.2813491-7-armbru@redhat.com>
2018-08-24qobject: Drop superfluous includes of qemu-common.hMarkus Armbruster1-1/+0
Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20180823164025.12553-53-armbru@redhat.com>
2018-03-19qapi: Remove qobject_to_X() functionsMax Reitz1-11/+0
They are no longer needed now. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Message-Id: <20180224154033.29559-5-mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Eric Blake <eblake@redhat.com>
2018-03-19qapi: Replace qobject_to_X(o) by qobject_to(X, o)Max Reitz1-3/+3
This patch was generated using the following Coccinelle script: @@ expression Obj; @@ ( - qobject_to_qnum(Obj) + qobject_to(QNum, Obj) | - qobject_to_qstring(Obj) + qobject_to(QString, Obj) | - qobject_to_qdict(Obj) + qobject_to(QDict, Obj) | - qobject_to_qlist(Obj) + qobject_to(QList, Obj) | - qobject_to_qbool(Obj) + qobject_to(QBool, Obj) ) and a bit of manual fix-up for overly long lines and three places in tests/check-qjson.c that Coccinelle did not find. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Message-Id: <20180224154033.29559-4-mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> [eblake: swap order from qobject_to(o, X), rebase to master, also a fix to latent false-positive compiler complaint about hw/i386/acpi-build.c] Signed-off-by: Eric Blake <eblake@redhat.com>
2018-02-09Include qapi/qmp/qobject.h exactly where neededMarkus Armbruster1-1/+0
Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20180201111846.21846-11-armbru@redhat.com>
2018-02-09Include qapi/error.h exactly where neededMarkus Armbruster1-1/+0
This cleanup makes the number of objects depending on qapi/error.h drop from 1910 (out of 4743) to 1612 in my "build everything" tree. While there, separate #include from file comment with a blank line, and drop a useless comment on why qemu/osdep.h is included first. Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20180201111846.21846-5-armbru@redhat.com> [Semantic conflict with commit 34e304e975 resolved, OSX breakage fixed]
2017-11-17qapi: Add qobject_is_equal()Max Reitz1-0/+54
This generic function (along with its implementations for different types) determines whether two QObjects are equal. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Message-id: 20171114180128.17076-4-mreitz@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-06-20qnum: add uint typeMarc-André Lureau1-0/+64
In order to store integer values between INT64_MAX and UINT64_MAX, add a uint64_t internal representation. Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20170607163635.17635-10-marcandre.lureau@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2017-06-20qapi: merge QInt and QFloat in QNumMarc-André Lureau1-0/+159
We would like to use a same QObject type to represent numbers, whether they are int, uint, or floats. Getters will allow some compatibility between the various types if the number fits other representations. Add a few more tests while at it. Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Message-Id: <20170607163635.17635-7-marcandre.lureau@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> [parse_stats_intervals() simplified a bit, comment in test_visitor_in_int_overflow() tidied up, suppress bogus warnings] Signed-off-by: Markus Armbruster <armbru@redhat.com>