We already documented that qapi names should match specific
patterns (such as starting with a letter unless it was an enum
value or a downstream extension). Tighten that from a suggestion
into a hard requirement, which frees up names beginning with a
single underscore for qapi internal usage.
The tighter regex doesn't forbid everything insane that a user
could provide (for example, a user could name a type 'Foo-lookup'
to collide with the generated 'Foo_lookup[]' for an enum 'Foo'),
but does a good job at protecting the most obvious uses, and
also happens to reserve single leading underscore for later use.
The handling of enum values starting with a digit is tricky:
commit 9fb081e introduced a subtle bug by using c_name() on
a munged value, which would allow an enum to include the
member 'q-int' in spite of our reservation. Furthermore,
munging with a leading '_' would fail our tighter regex. So
fix it by only munging for leading digits (which are never
ticklish in c_name()) and by using a different prefix (I
picked 'D', although any letter should do).
Add new tests, reserved-member-underscore and reserved-enum-q,
to demonstrate the tighter checking.
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1447836791-369-22-git-send-email-eblake@redhat.com>
Message-Id: <1447883135-18020-1-git-send-email-eblake@redhat.com>
[Eric's fixup squashed in]
Signed-off-by: Markus Armbruster <armbru@redhat.com>
We are not ready (and might never be ready) to declare
introspection stable between releases. Clients written to
control multiple versions of qemu, and desiring to know
whether a particular member is supported for a given
command, must be prepared to locate that member in spite
of qapi changes that may affect the member's location or
type within the overall object, even though such changes
did not break QMP wire back-compatibility.
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1447264202-19554-1-git-send-email-eblake@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
qapi-code-gen.txt already claims that types, commands, and
events share a common namespace; set this in stone by further
documenting that our introspection output will never have
collisions with the same name tied to more than one meta-type.
Our largest QMP enum currently has 125 values, our largest
object type has 27 members, and the mean for each is less than
10. These sizes are small enough that the per-element overhead
of O(log n) binary searching probably outweighs the speed
possible with direct O(n) linear searching (a better algorithm
with more overhead will only beat a leaner naive algorithm only
as you scale to larger input sizes).
Arguably, the overall SchemaInfo array could be sorted by name;
there, we currently have 531 entities, large enough for a binary
search to be faster than linear. However, remember that we have
mutually-recursive types, which means there is no topological
ordering that will allow clients to learn all information about
that type in a single linear pass; thus clients will want to do
random access over the data, and they will probably read the
introspection output into a hashtable for O(1) lookup rather
than O(log n) binary searching, at which point, pre-sorting our
introspection output doesn't help the client.
It doesn't help that sorting can be subjective if you introduce
locales into the mix (I'm not experienced enough with Python
to know for sure, but at least it looks like it defaults to
sorting in the C locale even when run under a different locale).
And while our current introspection output is deterministic
(because we visit entities in a sorted order), we may want
to change that order in the future (such as using OrderedDict
to stick to .json declaration order).
For these reasons, we simply document that clients should not
rely on any particular order of items in introspection output.
And since it is now a documented part of the contract, we have
the freedom to later rearrange output if needed, without
worrying about breaking well-written clients.
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1446791754-23823-13-git-send-email-eblake@redhat.com>
[Commit message tweaked]
Signed-off-by: Markus Armbruster <armbru@redhat.com>
For the sake of humans reading introspection output, it is nice
to have the name of implicit array types be recognizable as
arrays of the underlying type. However, while this patch allows
humans to skip from a command with return type "[123]" straight
to the definition of type "123" without having to first inspect
type "[123]", document that this shortcut should not be taken by
client apps.
This makes the resulting introspection string slightly larger by
default (just over 200 bytes), but it's in the noise (less than
0.3% of the overall 70k size of 'query-qmp-capabilities').
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1446791754-23823-12-git-send-email-eblake@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
c_name() produces names starting with 'q_' when protecting a
dictionary member name that would fail to directly compile, but
in doing so can cause clashes with any member name already
beginning with 'q-' or 'q_'. Likewise, we create a C name 'has_'
for any optional member that can clash with any member name
beginning with 'has-' or 'has_'.
Technically, rather than blindly reserving the namespace,
we could try to complain about user names only when an actual
collision occurs, or even teach c_name() how to munge names
to avoid collisions. But it is not trivial, especially when
collisions can occur across multiple types (such as via
inheritance or flat unions). Besides, no existing .json
files are trying to use these names. So it's easier to just
outright forbid the potential for collision. We can always
relax things in the future if a real need arises for QMP to
express member names that have been forbidden here.
'has_' only has to be reserved for struct/union member names,
while 'q_' is reserved everywhere (matching the fact that
only members can be optional, while we use c_name() for munging
both members and entities). Note that we could relax 'q_'
restrictions on entities independently from member names; for
example, c_name('qmp_' + 'unix') would result in a different
function name than our current 'qmp_' + c_name('unix').
Update and add tests to cover the new error messages.
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1445898903-12082-6-git-send-email-eblake@redhat.com>
[Consistently pass protect=False to c_name(); commit message tweaked
slightly]
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Type names ending in 'List' can clash with qapi list types in
generated C. We don't currently use such names. It is easier to
outlaw them now than to worry about how to resolve such a clash
in the future. For precedence, see commit 4dc2e69, which did the
same for names ending in 'Kind' versus implicit enum types for
qapi unions.
Update the testsuite to match.
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1445898903-12082-5-git-send-email-eblake@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
We had some pointless differences in the generated code for visit,
command marshalling, and events; unifying them makes it easier for
future patches to consolidate to common helper functions.
This is one patch of a series to clean up these differences.
This patch names the local visitor variable 'v' rather than 'm'.
Related objects, such as 'QapiDeallocVisitor', are also named by
their initials instead of an unrelated leading m.
No change in semantics to the generated code.
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1443565276-4535-12-git-send-email-eblake@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
We had some pointless differences in the generated code for visit,
command marshalling, and events; unifying them makes it easier for
future patches to consolidate to common helper functions.
This is one patch of a series to clean up these differences.
This patch consistently names the local error variable 'err' rather
than 'local_err'.
No change in semantics to the generated code.
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1443565276-4535-11-git-send-email-eblake@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
To eliminate the temptation for clients to look up types by name
(which are not ABI), replace all type names by meaningless strings.
Reduces output of query-schema by 13 out of 85KiB.
As a debugging aid, provide option -u to suppress the hiding.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <1442401589-24189-27-git-send-email-armbru@redhat.com>
qapi/introspect.json defines the introspection schema. It's designed
for QMP introspection, but should do for similar uses, such as QGA.
The introspection schema does not reflect all the rules and
restrictions that apply to QAPI schemata. A valid QAPI schema has an
introspection value conforming to the introspection schema, but the
converse is not true.
Introspection lowers away a number of schema details, and makes
implicit things explicit:
* The built-in types are declared with their JSON type.
All integer types are mapped to 'int', because how many bits we use
internally is an implementation detail. It could be pressed into
external interface service as very approximate range information,
but that's a bad idea. If we need range information, we better do
it properly.
* Implicit type definitions are made explicit, and given
auto-generated names:
- Array types, named by appending "List" to the name of their
element type, like in generated C.
- The enumeration types implicitly defined by simple union types,
named by appending "Kind" to the name of their simple union type,
like in generated C.
- Types that don't occur in generated C. Their names start with ':'
so they don't clash with the user's names.
* All type references are by name.
* The struct and union types are generalized into an object type.
* Base types are flattened.
* Commands take a single argument and return a single result.
Dictionary argument or list result is an implicit type definition.
The empty object type is used when a command takes no arguments or
produces no results.
The argument is always of object type, but the introspection schema
doesn't reflect that.
The 'gen': false directive is omitted as implementation detail.
The 'success-response' directive is omitted as well for now, even
though it's not an implementation detail, because it's not used by
QMP.
* Events carry a single data value.
Implicit type definition and empty object type use, just like for
commands.
The value is of object type, but the introspection schema doesn't
reflect that.
* Types not used by commands or events are omitted.
Indirect use counts as use.
* Optional members have a default, which can only be null right now
Instead of a mandatory "optional" flag, we have an optional default.
No default means mandatory, default null means optional without
default value. Non-null is available for optional with default
(possible future extension).
* Clients should *not* look up types by name, because type names are
not ABI. Look up the command or event you're interested in, then
follow the references.
TODO Should we hide the type names to eliminate the temptation?
New generator scripts/qapi-introspect.py computes an introspection
value for its input, and generates a C variable holding it.
It can generate awfully long lines. Marked TODO.
A new test-qmp-input-visitor test case feeds its result for both
tests/qapi-schema/qapi-schema-test.json and qapi-schema.json to a
QmpInputVisitor to verify it actually conforms to the schema.
New QMP command query-qmp-schema takes its return value from that
variable. Its reply is some 85KiBytes for me right now.
If this turns out to be too much, we have a couple of options:
* We can use shorter names in the JSON. Not the QMP style.
* Optionally return the sub-schema for commands and events given as
arguments.
Right now qmp_query_schema() sends the string literal computed by
qmp-introspect.py. To compute sub-schema at run time, we'd have to
duplicate parts of qapi-introspect.py in C. Unattractive.
* Let clients cache the output of query-qmp-schema.
It changes only on QEMU upgrades, i.e. rarely. Provide a command
query-qmp-schema-hash. Clients can have a cache indexed by hash,
and re-query the schema only when they don't have it cached. Even
simpler: put the hash in the QMP greeting.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
'gen': false needs to stay for now, because netdev_add is still using
it.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Message-Id: <1442401589-24189-25-git-send-email-armbru@redhat.com>
It doesn't take a 'props' argument, let alone one in the format
"NAME=VALUE,..."
The bogus arguments specification doesn't matter due to 'gen': false.
Clean it up to be incomplete rather than wrong, and document the
incompleteness.
While there, improve netdev_add usage example in the manual: add a
device option to show how it's done.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Message-Id: <1442401589-24189-24-git-send-email-armbru@redhat.com>
It's first class, because unlike '**', it actually works, i.e. doesn't
require 'gen': false.
'**' will go away next.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Clarify how they map to JSON. Add how they map to C. Fix the
reference to StringInputVisitor.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Message-Id: <1442401589-24189-20-git-send-email-armbru@redhat.com>
gen_marshal_output() uses its parameter name only for name of the
generated function. Name it after the type being marshaled instead of
its caller, and drop duplicates.
Saves 7 copies of qmp_marshal_output_int() in qemu-ga, and one copy of
qmp_marshal_output_str() in qemu-system-*.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Message-Id: <1442401589-24189-19-git-send-email-armbru@redhat.com>
These functions marshal both input and output.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Message-Id: <1442401589-24189-17-git-send-email-armbru@redhat.com>
Generate just 'FOO' instead of 'struct FOO' when possible.
Drop helper functions that are now unused.
Make pep8 and pylint reasonably happy.
Rename generate_FOO() functions to gen_FOO() for consistency.
Use more consistent and sensible variable names.
Consistently use c_ for mapping keys when their value is a C
identifier or type.
Simplify gen_enum() and gen_visit_union()
Consistently use single quotes for C text string literals.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <1442401589-24189-14-git-send-email-armbru@redhat.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Duplicated in commit 21cd70d. Yes, we can't import qapi-types, but
that's no excuse. Move the helpers from qapi-types.py to qapi.py, and
replace the duplicates in qapi-event.py.
The generated event enumeration type's lookup table becomes
const-correct (see commit 2e4450f), and uses explicit indexes instead
of relying on order (see commit 912ae9c).
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <1442401589-24189-10-git-send-email-armbru@redhat.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Fixes flat unions to get the base's base members. Test case is from
commit 2fc0043, in qapi-schema-test.json:
{ 'union': 'UserDefFlatUnion',
'base': 'UserDefUnionBase',
'discriminator': 'enum1',
'data': { 'value1' : 'UserDefA',
'value2' : 'UserDefB',
'value3' : 'UserDefB' } }
{ 'struct': 'UserDefUnionBase',
'base': 'UserDefZero',
'data': { 'string': 'str', 'enum1': 'EnumOne' } }
{ 'struct': 'UserDefZero',
'data': { 'integer': 'int' } }
Patch's effect on UserDefFlatUnion:
struct UserDefFlatUnion {
/* Members inherited from UserDefUnionBase: */
+ int64_t integer;
char *string;
EnumOne enum1;
/* Own members: */
union { /* union tag is @enum1 */
void *data;
UserDefA *value1;
UserDefB *value2;
UserDefB *value3;
};
};
Flat union visitors remain broken. They'll be fixed next.
Code is generated in a different order now, but that doesn't matter.
The two guards QAPI_TYPES_BUILTIN_STRUCT_DECL and
QAPI_TYPES_BUILTIN_CLEANUP_DECL are replaced by just
QAPI_TYPES_BUILTIN.
Two ugly special cases for simple unions now stand out like sore
thumbs:
1. The type tag is named 'type' everywhere, except in generated C,
where it's 'kind'.
2. QAPISchema lowers simple unions to semantically equivalent flat
unions. However, the C generated for a simple unions differs from
the C generated for its equivalent flat union, and we therefore
need special code to preserve that pointless difference for now.
Mark both TODO.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
The camel_to_upper() method applies some heuristics to turn
a mixed case type name into an all-uppercase name. This is
used for example, to generate enum constant name prefixes.
The heuristics don't also generate a satisfactory name
though. eg
{ 'enum': 'QCryptoTLSCredsEndpoint',
'data': ['client', 'server']}
Results in Q_CRYPTOTLS_CREDS_ENDPOINT_CLIENT. This has
an undesirable _ after the initial Q and is missing an
_ between the CRYPTO & TLS strings.
Rather than try to add more and more heuristics to try
to cope with this, simply allow the QAPI schema to
specify the desired enum constant prefix explicitly.
eg
{ 'enum': 'QCryptoTLSCredsEndpoint',
'prefix': 'QCRYPTO_TLS_CREDS_ENDPOINT',
'data': ['client', 'server']}
Now gives the QCRYPTO_TLS_CREDS_ENDPOINT_CLIENT name.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Clean up white-space, brace placement, and superfluous #ifdef
QAPI_TYPES_BUILTIN_CLEANUP_DEF.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
In generated command handlers, the assignment to retval dominates its
only use. Therefore, its initialization is useless. Drop it.
Suggested-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reproducer: with
{ 'command': 'user_def_cmd4', 'returns': { 'a': 'int' } }
added to qapi-schema-test.json, qapi-commands.py dies when it tries to
generate the command handler function
Traceback (most recent call last):
File "/work/armbru/qemu/scripts/qapi-commands.py", line 359, in <module>
ret = generate_command_decl(cmd['command'], arglist, ret_type) + "\n"
File "/work/armbru/qemu/scripts/qapi-commands.py", line 29, in generate_command_decl
ret_type=c_type(ret_type), name=c_name(name),
File "/work/armbru/qemu/scripts/qapi.py", line 927, in c_type
assert isinstance(value, str) and value != ""
AssertionError
because the return type doesn't exist.
Simply outlaw this usage, and drop or dumb down test cases accordingly.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
A command's or event's 'data' must be a struct type, given either as a
dictionary, or as struct type name.
Commit dd883c6 tightened the checking there, but not enough: we still
accept 'union'. Fix to reject it.
We may want to support union types there, but we'll have to extend
qapi-commands.py and qapi-events.py for it.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Use c_name() instead of ad hoc code. Doesn't upcase the -p prefix,
which is an improvement in my book. Unbreaks prefix containing '.',
but other funny characters remain broken. To be fixed next.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
It's idempotent.
While there, update examples to current code.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Commit 87a560c4 added it in the wrong place. Commit 59a2c4ce added it
in the right place, but didn't remove it from the wrong place. Do
that now.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Mandatory option is silly, and the error handling is missing: the
programs crash when -i isn't supplied. Make it an argument, and check
it properly.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
We have more than one qapi schema in use by more than one protocol.
Add a new term 'Client JSON Protocol' for use throughout the
document, to avoid confusion on whether something refers only to
QMP and not QGA.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Referring to "type" as both a meta-type (built-in, enum, union,
alternate, or struct) and a specific type (the name that the
schema uses for declaring structs) is confusing. Now that the
generator accepts 'struct' as a synonym for 'type', update all
documentation to use saner wording.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
The next patch will quit special-casing "'union':'Foo',
'discriminator':{}" and instead use "'alternate':'Foo'".
Separating docs from implementation makes it easier to focus
on wording without holding up code. In particular, making
alternate a separate type makes for a nice type hierarchy:
/-------- meta-type ------\
/ | \
simple types alternate complex types
| | | |
built-in enum type(struct) union
| \ / / \
numeric string simple flat
A later patch will then clean up 'type' vs. 'struct'
confusion.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Go into more details about the various types of valid expressions
in a qapi schema, including tweaks to document fixes being done
later in the current patch series. Also fix some stale and missing
documentation in the QMP specification.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
While our top-level COPYING with its GPLv2+ license applies to
any documentation file that omits explicit instructions, these
days it's better to be a good example of calling out our
intentions. Correct use of GPL requires the use of a copyright
statement, so I'm adding notice to two QAPI documents, by
attributing these files to the initial authors and major
contributors. I used:
$ git blame --line-porcelain $file \
| sed -n 's/^author //p' | sort | uniq -c | sort -rn
to determine authorship of these two files. qmp-spec.txt blames
entirely to Red Hat (easy, since my contribution falls in that
category); while qapi-code-gen.txt has multiple contributors
representing multiple entities. But since it was originally
supplied by Michael Roth, the notice I added there copies the
notice he has used in other files. As there is no intended
change in license from the implicit one previously present from
the top level, I have not bothered to CC other contributors;
if we want to weaken things to something looser (such as LGPL)
so that there is no question that someone re-implementing the
spec is not forced to use GPL, that would be a different commit.
CC: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Commit 21cd70d added event support but didn't document what the
generated code looks like. Commit 05dfb26 removed some unwanted
spaces in the generated code, but didn't reflect those changes
into the documentation. Finally, the docs start with a big
disclaimer about QMP not using QAPI yet, which feels rather stale.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
qapi-event.py will parse the schema and generate qapi-event.c, then
the API in qapi-event.c can be used to handle events in qemu code.
All API have prefix "qapi_event".
The script mainly includes two parts: generate API for each event
define, generate an enum type for all defined events.
Since in some cases the real emit behavior may change, for example,
qemu-img would not send a event, a callback layer is used to
control the behavior. As a result, the stubs at compile time
can be saved, the binding of block layer code and monitor code
will become looser.
Signed-off-by: Wenchao Xia <wenchaoqemu@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
The purpose of this change is to help create a json file containing
common definitions; each bit of generated C code must be emitted
only one time.
A second history global to all QAPISchema instances has been added
to detect when a file is included more than one time and skip these
includes.
It does not act as a stack and the changes made to it by the
__init__ function are propagated back to the caller so it's really
a global state.
Signed-off-by: Benoit Canet <benoit@irqsave.net>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
While there, pare down the shell prompts.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
We commonly use the error API like this:
err = NULL;
foo(..., &err);
if (err) {
goto out;
}
bar(..., &err);
Every error source is checked separately. The second function is only
called when the first one succeeds. Both functions are free to pass
their argument to error_set(). Because error_set() asserts no error
has been set, this effectively means they must not be called with an
error set.
The qapi-generated code uses the error API differently:
// *errp was initialized to NULL somewhere up the call chain
frob(..., errp);
gnat(..., errp);
Errors accumulate in *errp: first error wins, subsequent errors get
dropped. To make this work, the second function does nothing when
called with an error set. Requires non-null errp, or else the second
function can't see the first one fail.
This usage has also bled into visitor tests, and two device model
object property getters rtc_get_date() and balloon_stats_get_all().
With the "accumulate" technique, you need fewer error checks in
callers, and buy that with an error check in every callee. Can be
nice.
However, mixing the two techniques is confusing. You can't use the
"accumulate" technique with functions designed for the "check
separately" technique. You can use the "check separately" technique
with functions designed for the "accumulate" technique, but then
error_set() can't catch you setting an error more than once.
Standardize on the "check separately" technique for now, because it's
overwhelmingly prevalent.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Input and output marshalling functions do it differently. Change them
to work the same: initialize the I/O visitor, use it, clean it up,
initialize the dealloc visitor, use it, clean it up.
This delays dealloc visitor initialization in output marshalling
functions, and input visitor cleanup in input marshalling functions.
No functional change, but the latter will be convenient when I change
the error handling.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
The primitive uses JSON syntax, and include paths are relative to the file using the directive:
{ 'include': 'path/to/file.json' }
Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Use an explicit input file on the command-line instead of reading from standard
input.
It also outputs the proper file name when there's an error.
Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Since enum based discriminators provide better type-safety and
ensure that future qapi additions do not forget to adjust dependent
unions, forbid using string as discriminator from now on.
Signed-off-by: Wenchao Xia <wenchaoqemu@gmail.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
By default, any union will automatically generate a enum type as
"[UnionName]Kind" in C code, and it is duplicated when the discriminator
is specified as a pre-defined enum type in schema. After this patch,
the pre-defined enum type will be really used as the switch case
condition in generated C code, if discriminator is an enum field.
Signed-off-by: Wenchao Xia <wenchaoqemu@gmail.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
The QMP wire format uses "", not '', around strings.
* docs/qapi-code-gen.txt: Fix typo.
Signed-off-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
This introduces a new 'base' key for struct definitions that refers to
another struct type. On the JSON level, the fields of the base type are
included directly into the same namespace as the fields of the defined
type, like with unions. On the C level, a pointer to a struct of the
base type is included.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
The discriminator for anonymous unions is the data type. This allows to
have a union type that allows both of these:
{ 'file': 'my_existing_block_device_id' }
{ 'file': { 'filename': '/tmp/mydisk.qcow2', 'read-only': true } }
Unions like this are specified in the schema with an empty dict as
discriminator. For this example you could take:
{ 'union': 'BlockRef',
'discriminator': {},
'data': { 'definition': 'BlockOptions',
'reference': 'str' } }
{ 'type': 'ExampleObject',
'data: { 'file': 'BlockRef' } }
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Eric Blake
Markus Armbruster
Daniel P. Berrange
Wenchao Xia
Benoît Canet
Lluís Vilanova
Kevin Wolf