Commit graph

105 commits

Author SHA1 Message Date
David Hildenbrand 8f69c83634
qapi: Rewrite string-input-visitor's integer and list parsing
The input visitor has some problems right now, especially
- unsigned type "Range" is used to process signed ranges, resulting in
inconsistent behavior and ugly/magical code
- uint64_t are parsed like int64_t, so big uint64_t values are not
supported and error messages are misleading
- lists/ranges of int64_t are accepted although no list is parsed and
we should rather report an error
- lists/ranges are preparsed using int64_t, making it hard to
implement uint64_t values or uint64_t lists
- types that don't support lists don't bail out
- visiting beyond the end of a list is not handled properly
- we don't actually parse lists, we parse *sets*: members are sorted,
and duplicates eliminated

So let's rewrite it by getting rid of usage of the type "Range" and
properly supporting lists of int64_t and uint64_t (including ranges of
both types), fixing the above mentioned issues.

Lists of other types are not supported and will properly report an
error. Virtual walks are now supported.

Tests have to be fixed up:
- Two BUGs were hardcoded that are fixed now
- The string-input-visitor now actually returns a parsed list and not
an ordered set.

Please note that no users/callers have to be fixed up. Candidates using
visit_type_uint16List() and friends are:
- backends/hostmem.c:host_memory_backend_set_host_nodes()
-- Code can deal with duplicates/unsorted lists
- numa.c::query_memdev()
-- via object_property_get_uint16List(), the list will still be sorted
and without duplicates (via host_memory_backend_get_host_nodes())
- qapi-visit.c::visit_type_Memdev_members()
- qapi-visit.c::visit_type_NumaNodeOptions_members()
- qapi-visit.c::visit_type_RockerOfDpaGroup_members
- qapi-visit.c::visit_type_RxFilterInfo_members()
-- Not used with string-input-visitor.

Backports commit c9fba9de89db51a07689e2cba4865a1e564b8f0f from qemu
2018-12-18 04:57:25 -05:00
David Hildenbrand d2e0fae69b
qapi: Fix string-input-visitor to reject NaN and infinities
The string-input-visitor happily accepts NaN and infinities when parsing
numbers (doubles). They shouldn't. Fix that.

Also, add two test cases, testing if "NaN" and "inf" is properly
rejected.

Backports commit 4b69d4c3d7c133ebc9393ef3f86ce38831921cb6 from qemu
2018-12-18 04:49:36 -05:00
Marc-André Lureau 0087625b7e
qobject: Modify qobject_ref() to return obj
For convenience and clarity, make it possible to call qobject_ref() at
the time when the reference is associated with a variable, or
argument, by making qobject_ref() return the same pointer as given.
Use that to simplify the callers.

Backports commit f5a74a5a50387c6f980b2e2f94f062487a1826da from qemu
2018-05-04 10:24:10 -04:00
Marc-André Lureau ab4528c1e4
qobject: Replace qobject_incref/QINCREF qobject_decref/QDECREF
Now that we can safely call QOBJECT() on QObject * as well as its
subtypes, we can have macros qobject_ref() / qobject_unref() that work
everywhere instead of having to use QINCREF() / QDECREF() for QObject
and qobject_incref() / qobject_decref() for its subtypes.

The replacement is mechanical, except I broke a long line, and added a
cast in monitor_qmp_cleanup_req_queue_locked(). Unlike
qobject_decref(), qobject_unref() doesn't accept void *.

Note that the new macros evaluate their argument exactly once, thus no
need to shout them.

Backports commit cb3e7f08aeaab0ab13e629ce8496dca150a449ba from qemu
2018-05-04 10:16:07 -04:00
Max Reitz 65b2b73b12
qapi: Make more of qobject_to()
This patch reworks some places which use either qobject_type() checks
plus qobject_to(), where the latter alone is sufficient, or NULL checks
plus qobject_type() checks where we can simply do a qobject_to() != NULL
check.

Backports commit 532fb532847365f61a9c6e1291b6588a43bc1cc4 from qemu
2018-03-20 11:05:44 -04:00
Max Reitz 275b2ac328
qapi: Replace qobject_to_X(o) by qobject_to(X, o)
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.

Backports commit 7dc847ebba953db90853d15f140c20eef74d4fb2 from qemu
2018-03-20 10:55:57 -04:00
Markus Armbruster 3277400723
qapi: Move qapi-schema.json to qapi/, rename generated files
Move qapi-schema.json to qapi/, so it's next to its modules, and all
files get generated to qapi/, not just the ones generated for modules.

Consistently name the generated files qapi-MODULE.EXT:
qmp-commands.[ch] become qapi-commands.[ch], qapi-event.[ch] become
qapi-events.[ch], and qmp-introspect.[ch] become qapi-introspect.[ch].
This gets rid of the temporary hacks in scripts/qapi/commands.py,
scripts/qapi/events.py, and scripts/qapi/common.py.

Backports commit eb815e248f50cde9ab86eddd57eca5019b71ca78 from qemu
2018-03-09 11:35:11 -05:00
Markus Armbruster 311d659acf
qapi: Empty out qapi-schema.json
The previous commit improved compile time by including less of the
generated QAPI headers. This is impossible for stuff defined directly
in qapi-schema.json, because that ends up in headers that that pull in
everything.

Move everything but include directives from qapi-schema.json to new
sub-module qapi/misc.json, then include just the "misc" shard where
possible.

It's possible everywhere, except:

* monitor.c needs qmp-command.h to get qmp_init_marshal()

* monitor.c, ui/vnc.c and the generated qapi-event-FOO.c need
qapi-event.h to get enum QAPIEvent

Perhaps we'll get rid of those some other day.

Adding a type to qapi/migration.json now recompiles some 120 instead
of 2300 out of 5100 objects.

Backports commit 112ed241f5d9a411dbca92bdf597151cb853c6a7 from qemu
2018-03-09 10:23:27 -05:00
Markus Armbruster 1496dddeab
Include qapi/qmp/qlist.h exactly where needed
This cleanup makes the number of objects depending on qapi/qmp/qlist.h
drop from 4551 (out of 4743) to 16 in my "build everything" tree.

While there, separate #include from file comment with a blank line.

Backports commit 47e6b297e76007c04a1e9c492006fe093d932cd9 from qemu
2018-03-08 08:50:06 -05:00
Markus Armbruster 801dbfce3d
Include qapi/qmp/qobject.h exactly where needed
Backports commit 5ee9d2fe9e1e15d6e4a112220da3ad8a3512819b from qemu
2018-03-08 08:48:27 -05:00
Max Reitz e42e3307f7
qapi/qnull: Add own header
Backports commit 84be629d5545b5ccc5bff2824e4288677e27de9c from qemu
2018-03-08 08:35:23 -05:00
Markus Armbruster f89de73110
qdict qlist: Make most helper macros functions
The macro expansions of qdict_put_TYPE() and qlist_append_TYPE() need
qbool.h, qnull.h, qnum.h and qstring.h to compile. We include qnull.h
and qnum.h in the headers, but not qbool.h and qstring.h. Works,
because we include those wherever the macros get used.

Open-coding these helpers is of dubious value. Turn them into
functions and drop the includes from the headers.

This cleanup makes the number of objects depending on qapi/qmp/qnum.h
from 4551 (out of 4743) to 46 in my "build everything" tree. For
qapi/qmp/qnull.h, the number drops from 4552 to 21.

Backports commit 15280c360e54a65e2c7be1a47bfbe41dce1ef986 from qemu
2018-03-08 08:30:10 -05:00
Markus Armbruster 4a7abec7c9
qapi: Use QNull for a more regular visit_type_null()
Make visit_type_null() take an @obj argument like its buddies. This
helps keep the next commit simple.

Backports commit d2f95f4d482374485234790a6fc3cca29ebb7355 from qemu
2018-03-07 16:50:16 -05:00
Markus Armbruster 3fd0ff8aa7
qapi: Separate type QNull from QObject
Backports commit 006ca09f3027d86346fce707e9295975c6558f42 from qemu
2018-03-07 16:43:51 -05:00
Markus Armbruster 566b097b85
Eliminate qapi/qmp/types.h
qapi/qmp/types.h is a convenience header to include a number of
qapi/qmp/ headers. Since we rarely need all of the headers
qapi/qmp/types.h includes, we bypass it most of the time. Most of the
places that use it don't need all the headers, either.

Include the necessary headers directly, and drop qapi/qmp/types.h.

Backports commit 6b67395762a4c8b6ca94364e0a0f616a6470c46a from qemu
2018-03-07 12:39:23 -05:00
Greg Kurz a125b35f1f
qapi: add explicit null to string input and output visitors
This may be used for deprecated object properties that are kept for
backwards compatibility.

Backports commit a733371214b68881d84725a3c71f60e2faf3b8e2 from qemu
2018-03-03 20:32:50 -05:00
Marc-André Lureau fef464c4cb
qapi: update the qobject visitor to use QNUM_U64
Switch to use QNum/uint where appropriate to remove i64 limitation.

The input visitor will cast i64 input to u64 for compatibility
reasons (existing json QMP client already use negative i64 for large
u64, and expect an implicit cast in qemu).

Note: before the patch, uint64_t values above INT64_MAX are sent over
json QMP as negative values, e.g. UINT64_MAX is sent as -1. After the
patch, they are sent unmodified. Clearly a bug fix, but we have to
consider compatibility issues anyway. libvirt should cope fine,
because its parsing of unsigned integers accepts negative values
modulo 2^64. There's hope that other clients will, too.

Backports commit 5923f85fb82df7c8c60a89458a5ae856045e5ab1 from qemu
2018-03-03 18:40:51 -05:00
Marc-André Lureau a57d8a5b50
qapi: Remove visit_start_alternate() parameter promote_int
Before the previous commit, parameter promote_int = true made
visit_start_alternate() with an input visitor avoid QTYPE_QINT
variants and create QTYPE_QFLOAT variants instead. This was used
where QTYPE_QINT variants were invalid.

The previous commit fused QTYPE_QINT with QTYPE_QFLOAT, rendering
promote_int useless and unused.

Backports commit 60390d2dc85ffade8981ca41e02335cb07353a6d from qemu
2018-03-03 18:34:35 -05:00
Lioncash a6623ce754
qapi: Update scripts to commit 01b2ffcedd94ad7b42bc870e4c6936c87ad03429 2018-03-03 18:32:12 -05:00
Marc-André Lureau dd77730d49
qapi: merge QInt and QFloat in QNum
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.

Backports commit 01b2ffcedd94ad7b42bc870e4c6936c87ad03429 from qemu
2018-03-03 18:16:28 -05:00
Marc-André Lureau f1dbfe6be6
qapi: Clean up qobject_input_type_number() control flow
Use the more common pattern to error out.

Backports commit 58634047b7deeab36e4b07c4744e44d698975561 from qemu
2018-03-03 17:40:45 -05:00
Markus Armbruster d70f3bfc6b
qobject-input-visitor: Document full_name_nth()
Backports commit 6c02258e143700314ebf268dae47eb23db17d1cf from qemu
2018-03-03 17:39:09 -05:00
Markus Armbruster 0d433af617
qobject-input-visitor: Catch misuse of end_struct vs. end_list
Backports commit 8b2e41d733850ec6a67a85743138e023cbb8921b from qemu
2018-03-03 17:38:16 -05:00
Markus Armbruster 5ab0d5af81
qapi: New QAPI_CLONE_MEMBERS()
QAPI_CLONE() returns a newly allocated QAPI object. Inconvenient when
we want to clone into an existing object. QAPI_CLONE_MEMBERS() does
exactly that.

Backports commit 4626a19c86c30d96cedbac2bd44ef8103303cb37 from qemu
2018-03-03 17:36:02 -05:00
Markus Armbruster 09efe97bfd
qapi: Fix string input visitor regression for empty lists
Visiting a list when input is the empty string should result in an
empty list, not an error. Noticed when commit 3d089ce belatedly added
tests, but simply accepted as weird then. It's actually a regression:
broken in commit 74f24cb, v2.7.0. Fix it, and throw in another test
case for empty string.

Backports commit d2788227c6185c72d88ef3127e9fed41686f8e39 from qemu
2018-03-03 17:30:42 -05:00
Markus Armbruster 247a511c4a
qapi: Factor out common part of qobject input visitor creation
Backports commit abe81bc21a6996c62e66ed2d051373c0df24f870 from qemu
2018-03-03 17:26:27 -05:00
Markus Armbruster 67cb4b0900
qapi: Fix object input visit beyond end of list
Backports commit 1f41a645b65530859bf5984aa08e103bb452b473 from qemu
2018-03-02 12:22:50 -05:00
Markus Armbruster ac1a61af47
qapi: Make input visitors detect unvisited list tails
Fix the design flaw demonstrated in the previous commit: new method
check_list() lets input visitors report that unvisited input remains
for a list, exactly like check_struct() lets them report that
unvisited input remains for a struct or union.

Implement the method for the qobject input visitor (straightforward),
and the string input visitor (less so, due to the magic list syntax
there). The opts visitor's list magic is even more impenetrable, and
all I can do there today is a stub with a FIXME comment. No worse
than before.

Backports commit a4a1c70dc759e5b81627e96564f344ab43ea86eb from qemu
2018-03-02 12:21:04 -05:00
Markus Armbruster e0ee098c4a
qapi: Drop unused non-strict qobject input visitor
The split between tests/test-qobject-input-visitor.c and
tests/test-qobject-input-strict.c now makes less sense than ever. The
next commit will take care of that.

Backports commit 048abb7b20c9f822ad9d4b730bade73b3311a47a from qemu
2018-03-02 12:14:52 -05:00
Markus Armbruster 2b7daee13b
qapi: Make string input and opts visitor require non-null input
The string input visitor tries to cope with null input. Null input
isn't used anywhere, and isn't covered by tests. Unsurprisingly, it
doesn't fully work: start_list() crashes because it passes the input
via parse_str() to strtoll() unchecked.

Make string_input_visitor_new() assert its argument isn't null, and
drop the code trying to deal with null input.

The opts visitor crashes when you try to actually visit something with
null input. Make opts_visitor_new() assert its argument isn't null,
mostly for clarity.

qobject_input_visitor_new() already asserts its argument isn't null.

Backports commit f332e830e38b3ff3953ef02ac04e409ae53769c5 from qemu
2018-03-02 12:10:07 -05:00
Markus Armbruster 50e3cda49a
qapi: Drop string input visitor method optional()
visit_optional() is to be called only between visit_start_struct() and
visit_end_struct(). Visitors that don't support struct visits,
i.e. don't implement start_struct(), end_struct(), have no use for it.
Clarify documentation.

The string input visitor doesn't support struct visits. Its
parse_optional() is therefore useless. Drop it.

Backports commit a8aec6de2ac1a5e36989fdfba29067b361009b75 from qemu
2018-03-02 12:07:55 -05:00
Markus Armbruster 84e5261cdf
qapi: Improve qobject input visitor error reporting
Error messages refer to nodes of the QObject being visited by name.
Trouble is the names are sometimes less than helpful:

* The name of the root QObject is whatever @name argument got passed
to the visitor, except NULL gets mapped to "null". We commonly pass
NULL. Not good.

Avoiding errors "at the root" mitigates. For instance,
visit_start_struct() can only fail when the visited object is not a
dictionary, and we commonly ensure it is beforehand.

* The name of a QDict's member is the member key. Good enough only
when this happens to be unique.

* The name of a QList's member is "null". Not good.

Improve error messages by referring to nodes by path instead, as
follows:

* The path of the root QObject is whatever @name argument got passed
to the visitor, except NULL gets mapped to "<anonymous>".

* The path of a root QDict's member is the member key.

* The path of a root QList's member is "[%u]", where %u is the list
index, starting at zero.

* The path of a non-root QDict's member is the path of the QDict
concatenated with "." and the member key.

* The path of a non-root QList's member is the path of the QList
concatenated with "[%u]", where %u is the list index.

For example, the incorrect QMP command

{ "execute": "blockdev-add", "arguments": { "node-name": "foo", "driver": "raw", "file": {"driver": "file" } } }

now fails with

{"error": {"class": "GenericError", "desc": "Parameter 'file.filename' is missing"}}

instead of

{"error": {"class": "GenericError", "desc": "Parameter 'filename' is missing"}}

and

{ "execute": "input-send-event", "arguments": { "device": "bar", "events": [ [] ] } }

now fails with

{"error": {"class": "GenericError", "desc": "Invalid parameter type for 'events[0]', expected: object"}}

instead of

{"error": {"class": "GenericError", "desc": "Invalid parameter type for 'null', expected: QDict"}}

Aside: calling the thing "parameter" is suboptimal for QMP, because
the root object is "arguments" there.

The qobject output visitor doesn't have this problem because it should
not fail. Same for dealloc and clone visitors.

The string visitors don't have this problem because they visit just
one value, whose name needs to be passed to the visitor as @name. The
string output visitor shouldn't fail anyway.

The options visitor uses QemuOpts names. Their name space is flat, so
the use of QDict member keys as names is fine. NULL names used with
roots and lists could conceivably result in bad error messages. Left
for another day.

Backports commit a9fc37f6bc3f2ab90585cb16493da9f6dcfbfbcf from qemu
2018-03-02 12:05:53 -05:00
Markus Armbruster a5cf19858d
qapi: Make QObject input visitor set *list reliably
qobject_input_start_struct() sets *list, except when it fails because
qobject_input_get_object() fails, i.e. the input object doesn't exist.

All the other input visitor start_struct(), start_list(),
start_alternate() always set *obj / *list.

Change qobject_input_start_struct() to match.

Backports commit 58561c27669ddf1c6d39ff8ce25837c6f2d9d92c from qemu
2018-03-02 11:31:58 -05:00
Markus Armbruster fdf09c6d12
qapi: Clean up after commit 3d344c2
Drop unused QIV_STACK_SIZE and unused qobject_input_start_struct()
parameter errp.

Backports commit b8874fbfd329b5084463bcacd1418d493a93c383 from qemu
2018-03-02 11:30:38 -05:00
Markus Armbruster d7da652d4e
qapi: Improve a QObject input visitor error message
The QObject input visitor has three error message formats:

* Parameter '%s' is missing
* "Invalid parameter type for '%s', expected: %s"
* "QMP input object member '%s' is unexpected"

The '%s' are member names (or "null", but I'll fix that later).

The last error message calls the thing "QMP input object member"
instead of "parameter". Misleading when the visitor is used on
QObjects that don't come from QMP. Change it to "Parameter '%s' is
unexpected".

Backports commit 910f738b851a263396fc85b2052e47f884ffead3 from qemu
2018-03-02 11:29:02 -05:00
Markus Armbruster d07bcef231
qmp: Eliminate silly QERR_QMP_* macros
The QERR_ macros are leftovers from the days of "rich" error objects.

QERR_QMP_BAD_INPUT_OBJECT, QERR_QMP_BAD_INPUT_OBJECT_MEMBER,
QERR_QMP_EXTRA_MEMBER are used in just one place now, except for one
use that has crept into qobject-input-visitor.c.

Drop these macros, to make the (bad) error messages more visible.

Backports commit 99fb0c53c038105bae68b02a3d9f1cbf7951ba10 from qemu
2018-03-02 11:28:17 -05:00
Daniel P. Berrange 83a5bf2d25
qapi: rename QmpOutputVisitor to QObjectOutputVisitor
The QmpOutputVisitor has no direct dependency on QMP. It is
valid to use it anywhere that one wants a QObject. Rename it
to better reflect its functionality as a generic QAPI
to QObject converter.

The commit before previous renamed the files, this one renames C
identifiers.

Backports commit 7d5e199ade76c53ec316ab6779800581bb47c50a from qemu
2018-02-27 08:05:33 -05:00
Daniel P. Berrange 2949a90977
qapi: rename QmpInputVisitor to QObjectInputVisitor
The QmpInputVisitor has no direct dependency on QMP. It is
valid to use it anywhere that one has a QObject. Rename it
to better reflect its functionality as a generic QObject
to QAPI converter.

The previous commit renamed the files, this one renames C identifiers.

Backports commit 09e68369a88d7de0f988972bf28eec1b80cc47f9 from qemu
2018-02-26 15:54:15 -05:00
Daniel P. Berrange 228f122248
qapi: rename *qmp-*-visitor* to *qobject-*-visitor*
The QMP visitors have no direct dependency on QMP. It is
valid to use them anywhere that one has a QObject. Rename them
to better reflect their functionality as a generic QObject
to QAPI converter.

This is the first of three parts: rename the files. The next two
parts will rename C identifiers. The split is necessary to make git
rename detection work.

Backports commit b3db211f3c80bb996a704d665fe275619f728bd4 from qemu
2018-02-26 15:42:37 -05:00
Marc-André Lureau be6e25bcc7
qapi: return a 'missing parameter' error
The 'old' dispatch code returned a QERR_MISSING_PARAMETER for missing
parameters, but the qapi qmp_dispatch() code uses
QERR_INVALID_PARAMETER_TYPE.

Improve qapi code to return QERR_MISSING_PARAMETER where
appropriate.

Fix expected error message in iotests.

Backports commit 1382d4abdf9619985e4078e37e49e487cea9935e from qemu
2018-02-26 05:19:53 -05:00
Marc-André Lureau ddc25c8aaf
qapi: assert list entry has a value
This helps to figure out the expectations.

Backports commit eac8e79ff749fc15e1dca4caccf1f38664ab4915 from qemu
2018-02-26 05:15:32 -05:00
Marc-André Lureau bd469af15f
qapi: add assert about root value
qiv->root should not be null, make that clearer with some assert.

Backports commit 5d0cbbcfeb59e1e3f5ee7d26b8a215382f6d9abd from qemu
2018-02-26 05:15:01 -05:00
Marc-André Lureau 1a138915a5
qapi: Fix crash when 'any' or 'null' parameter is missing
Unlike the other visit methods, visit_type_any() and visit_type_null()
neglect to check whether qmp_input_get_object() succeeded. They crash
when it fails. Reproducer:

{ "execute": "qom-set",
"arguments": { "path": "/machine", "property": "rtc-time" } }

Will crash with:

qapi/qapi-visit-core.c:277: visit_type_any: Assertion `!err != !*obj'
failed

Broken in commit 5c678ee. Fix by adding the missing error checks.

Backports commit c489780203f9b22aca5539ec7589b7140bdc951f from qemu
2018-02-26 05:13:54 -05:00
Paolo Bonzini 674805745b
qapi: change QmpInputVisitor to QSLIST
This saves a lot of memory compared to a statically-sized array,
or at least 24kb could be considered a lot on an Atari ST.
It also makes the code more similar to QmpOutputVisitor.

This removes the limit on the depth of a QObject that can be processed
into a QAPI tree. This is not a problem because QObjects can be
considered trusted; the text received on the QMP wire is untrusted
input, but the JSON parser already takes pains to limit the QObject tree
it creates. We don't need the QMP input visitor to limit it again.

Backports commit 3d344c2aabb7bc9b414321e3c52872901edebdda from qemu
2018-02-25 20:02:09 -05:00
Paolo Bonzini b14f1d7a80
qapi: change QmpOutputVisitor to QSLIST
This saves a little memory compared to the doubly-linked QTAILQ.

Backports commit fc76ae8b38783e82c109834573ba5d6f080440b5 from qemu
2018-02-25 19:59:16 -05:00
Lioncash 532f840dc3
qapi: Add new clone visitor
We have a couple places in the code base that want to deep-clone
one QAPI object into another, and they were resorting to serializing
the struct out to QObject then reparsing it. A much more efficient
version can be done by adding a new clone visitor.

Since cloning is still relatively uncommon, expose the use of the
new visitor via a QAPI_CLONE() macro that takes care of type-punning
the underlying function pointer, rather than generating lots of
unused functions for types that won't be cloned. And yes, we're
relying on the compiler treating all pointers equally, even though
a strict C program cannot portably do so - but we're not the first
one in the qemu code base to expect it to work (hello, glib!).

The choice of adding a fourth visitor type deserves some explanation.
On the surface, the clone visitor is mostly an input visitor (it
takes arbitrary input - in this case, another QAPI object - and
creates a new QAPI object during the course of the visit). But
ever since commit da72ab0 consolidated enum visits based on the
visitor type, using VISITOR_INPUT would cause us to run
visit_type_str(), even though for cloning there is nothing to do
(we just copy the enum value across, without regards to its mapping
to strings). Also, since our input happens to be a QAPI object,
we can also satisfy the internal checks for VISITOR_OUTPUT. So in
the end, I settled with a new VISITOR_CLONE, and chose its value
such that many internal checks can use 'v->type & mask', sticking
to 'v->type == value' where the difference matters.

Note that we can only clone objects (including alternates) and lists,
not built-ins or enums. The visitor core hides integer width from
the actual visitor (since commit 04e070d), and as long as that's the
case, we can't clone top-level integers. Then again, those can
always be cloned by direct copy, since they are not objects with
deep pointers, so it's no real loss. And restricting cloning to
just objects and lists is cleaner than restricting it to non-integers.
As such, I documented that the clone visitor is for direct use only
by code internal to QAPI, and should not be used on incomplete objects
(other than a hack to work around the fact that we allow NULL in place
of "" in visit_type_str() in other output visitors). Note that as
written, the clone visitor will never fail on a complete object.

Scalars (including enums) not at the root of the clone copy just fine
with no additional effort while visiting the scalar, by virtue of a
g_memdup() each time we push another struct onto the stack. Cloning
a string requires deduplication of a pointer, which means it can also
provide the guarantee of an input visitor of never producing NULL
even when still accepting NULL in place of "" the way the QMP output
visitor does.

Cloning an 'any' type could be possible by incrementing the QObject
refcnt, but it's not obvious whether that is better than implementing
a QObject deep clone. So for now, we document it as unsupported,
and intentionally omit the .type_any() callback to let a developer
know their usage needs implementation.

Add testsuite coverage for several different clone situations, to
ensure that the code is working. I also tested that valgrind was
happy with the test.

Backports commit a15fcc3cf69ee3d408f60d6cc316488d2b0249b4 from qemu
2018-02-25 01:34:12 -05:00
Eric Blake 85af4b2030
qapi: Add new visit_complete() function
Making each output visitor provide its own output collection
function was the only remaining reason for exposing visitor
sub-types to the rest of the code base. Add a polymorphic
visit_complete() function which is a no-op for input visitors,
and which populates an opaque pointer for output visitors. For
maximum type-safety, also add a parameter to the output visitor
constructors with a type-correct version of the output pointer,
and assert that the two uses match.

This approach was considered superior to either passing the
output parameter only during construction (action at a distance
during visit_free() feels awkward) or only during visit_complete()
(defeating type safety makes it easier to use incorrectly).

Most callers were function-local, and therefore a mechanical
conversion; the testsuite was a bit trickier, but the previous
cleanup patch minimized the churn here.

The visit_complete() function may be called at most once; doing
so lets us use transfer semantics rather than duplication or
ref-count semantics to get the just-built output back to the
caller, even though it means our behavior is not idempotent.

Generated code is simplified as follows for events:

|@@ -26,7 +26,7 @@ void qapi_event_send_acpi_device_ost(ACP
| QDict *qmp;
| Error *err = NULL;
| QMPEventFuncEmit emit;
|- QmpOutputVisitor *qov;
|+ QObject *obj;
| Visitor *v;
| q_obj_ACPI_DEVICE_OST_arg param = {
| info
|@@ -39,8 +39,7 @@ void qapi_event_send_acpi_device_ost(ACP
|
| qmp = qmp_event_build_dict("ACPI_DEVICE_OST");
|
|- qov = qmp_output_visitor_new();
|- v = qmp_output_get_visitor(qov);
|+ v = qmp_output_visitor_new(&obj);
|
| visit_start_struct(v, "ACPI_DEVICE_OST", NULL, 0, &err);
| if (err) {
|@@ -55,7 +54,8 @@ void qapi_event_send_acpi_device_ost(ACP
| goto out;
| }
|
|- qdict_put_obj(qmp, "data", qmp_output_get_qobject(qov));
|+ visit_complete(v, &obj);
|+ qdict_put_obj(qmp, "data", obj);
| emit(QAPI_EVENT_ACPI_DEVICE_OST, qmp, &err);

and for commands:

| {
| Error *err = NULL;
|- QmpOutputVisitor *qov = qmp_output_visitor_new();
| Visitor *v;
|
|- v = qmp_output_get_visitor(qov);
|+ v = qmp_output_visitor_new(ret_out);
| visit_type_AddfdInfo(v, "unused", &ret_in, &err);
|- if (err) {
|- goto out;
|+ if (!err) {
|+ visit_complete(v, ret_out);
| }
|- *ret_out = qmp_output_get_qobject(qov);
|-
|-out:
| error_propagate(errp, err);

Backports commit 3b098d56979d2f7fd707c5be85555d114353a28d from qemu
2018-02-25 01:20:03 -05:00
Eric Blake ec53301cda
qmp-output-visitor: Favor new visit_free() function
Now that we have a polymorphic visit_free(), we no longer need
qmp_output_visitor_cleanup(); however, we still need to
expose the subtype for qmp_output_get_qobject().

Backports commit 1830f22a6777cedaccd67a08f675d30f7a85ebfd from qemu
2018-02-25 01:12:27 -05:00
Eric Blake f008d93ac0
qmp-input-visitor: Favor new visit_free() function
Now that we have a polymorphic visit_free(), we no longer need
qmp_input_visitor_cleanup(); which in turn means we no longer
need to return a subtype from qmp_input_visitor_new() nor a
public upcast function.

Generated code changes to qmp-marshal.c look like:

|@@ -52,11 +52,10 @@ void qmp_marshal_add_fd(QDict *args, QOb
| {
| Error *err = NULL;
| AddfdInfo *retval;
|- QmpInputVisitor *qiv = qmp_input_visitor_new(QOBJECT(args), true);
| Visitor *v;
| q_obj_add_fd_arg arg = {0};
|
|- v = qmp_input_get_visitor(qiv);
|+ v = qmp_input_visitor_new(QOBJECT(args), true);
| visit_start_struct(v, NULL, NULL, 0, &err);
| if (err) {
| goto out;

Backports commit b70ce1018a251c0c33498d9c927a07cade655a5e from qemu
2018-02-25 01:10:53 -05:00
Eric Blake e88a7e260b
string-input-visitor: Favor new visit_free() function
Now that we have a polymorphic visit_free(), we no longer need
string_input_visitor_cleanup(); which in turn means we no longer
need to return a subtype from string_input_visitor_new() nor a
public upcast function.

Backports commit 7a0525c7be6b38d32d586e3fd12e7377ded21faa from qemu
2018-02-25 01:08:04 -05:00