Daniel P. Berrangé <berra...@redhat.com> writes:
> This removed the QapiFeatures enum and auto-generates an enum which
> exposes all features defined by the schema to code.
>
> The 'deprecated' and 'unstable' features still have a little bit of
> special handling, being force defined to be the 1st + 2nd features
> in the enum, regardless of whether they're used in the schema. This
> is because QAPI common code references these features.
>
> Signed-off-by: Daniel P. Berrangé <berra...@redhat.com>
> ---
> include/qapi/util.h | 5 --
> meson.build | 1 +
> scripts/qapi/features.py | 134 +++++++++++++++++++++++++++++++++++++++
> scripts/qapi/main.py | 2 +
> scripts/qapi/schema.py | 5 +-
> scripts/qapi/types.py | 4 +-
> 6 files changed, 144 insertions(+), 7 deletions(-)
> create mode 100644 scripts/qapi/features.py
>
> diff --git a/include/qapi/util.h b/include/qapi/util.h
> index a693cac9ea..9e390486c0 100644
> --- a/include/qapi/util.h
> +++ b/include/qapi/util.h
> @@ -11,11 +11,6 @@
> #ifndef QAPI_UTIL_H
> #define QAPI_UTIL_H
>
> -typedef enum {
> - QAPI_FEATURE_DEPRECATED,
> - QAPI_FEATURE_UNSTABLE,
> -} QapiFeature;
> -
> typedef struct QEnumLookup {
> const char *const *array;
> const uint64_t *const features;
> diff --git a/meson.build b/meson.build
> index 97f63aa86c..40002c59f5 100644
> --- a/meson.build
> +++ b/meson.build
> @@ -3268,6 +3268,7 @@ qapi_gen_depends = [ meson.current_source_dir() /
> 'scripts/qapi/__init__.py',
> meson.current_source_dir() / 'scripts/qapi/schema.py',
> meson.current_source_dir() / 'scripts/qapi/source.py',
> meson.current_source_dir() / 'scripts/qapi/types.py',
> + meson.current_source_dir() / 'scripts/qapi/features.py',
> meson.current_source_dir() / 'scripts/qapi/visit.py',
> meson.current_source_dir() / 'scripts/qapi-gen.py'
> ]
> diff --git a/scripts/qapi/features.py b/scripts/qapi/features.py
> new file mode 100644
> index 0000000000..9b77be6310
> --- /dev/null
> +++ b/scripts/qapi/features.py
> @@ -0,0 +1,134 @@
> +"""
> +QAPI types generator
> +
> +Copyright 2024 Red Hat
> +
> +This work is licensed under the terms of the GNU GPL, version 2.
> +# See the COPYING file in the top-level directory.
> +"""
> +
> +from typing import List, Optional
> +
> +from .common import c_enum_const, mcgen, c_name
> +from .gen import QAPISchemaMonolithicCVisitor
> +from .schema import (
> + QAPISchema,
> + QAPISchemaAlternatives,
> + QAPISchemaBranches,
> + QAPISchemaEntity,
> + QAPISchemaEnumMember,
> + QAPISchemaFeature,
> + QAPISchemaIfCond,
> + QAPISchemaObjectType,
> + QAPISchemaObjectTypeMember,
> + QAPISchemaType,
> + QAPISchemaVariants,
> +)
> +from .source import QAPISourceInfo
> +
> +
> +class QAPISchemaGenFeatureVisitor(QAPISchemaMonolithicCVisitor):
> +
> + def __init__(self, prefix: str):
> + super().__init__(
> + prefix, 'qapi-features',
> + ' * Schema-defined QAPI features',
> + __doc__)
> +
> + self.features = {}
> +
> + def visit_end(self) -> None:
> + features = []
> +
> + # We always want special features to have the same
> + # enum value across all schemas, since they're
> + # referenced from common code. Put them at the
> + # start of the list, regardless of whether they
> + # are actually referenced in the schema
> + for name in QAPISchemaFeature.SPECIAL_NAMES:
> + features.append(name)
> +
> + features.extend(sorted(self.features.keys()))
> +
> + if len(features) > 64:
> + raise Exception("Maximum of 64 schema features is permitted")
This is just one notch above assert len(features) > 64, so nope :)
Backends are not supposed to diagnose schema errors or constraint
violations. That's the frontend's job.
Perhaps the simplest way to check this in the frontend is to build a
feature set in QAPISchema: initialize in .__init__(), update in
._make_features(), fail right there when asked to make a 64th.
> +
> + self._genh.add("typedef enum {\n")
> + for name in features:
> + self._genh.add(f" {c_enum_const(self._prefix +
> 'QAPI_FEATURE', name)},\n")
This duplicates part of gen.gen_features(). Suggest to factor out the
common part as gen_feature().
Note for later: enum QapiFeature is defined in generated
qapi-features.h.
> +
> + self._genh.add("} " + c_name(self._prefix + 'QapiFeature') + ";\n")
> +
> + def _record(self, features: List[QAPISchemaFeature]):
> + for f in features:
> + # Special features are handled separately
> + if f.name in QAPISchemaFeature.SPECIAL_NAMES:
> + continue
> + self.features[f.name] = True
> +
> + def visit_enum_type(self,
> + name: str,
> + info: Optional[QAPISourceInfo],
> + ifcond: QAPISchemaIfCond,
> + features: List[QAPISchemaFeature],
> + members: List[QAPISchemaEnumMember],
> + prefix: Optional[str]) -> None:
> + self._record(features)
> +
> + def visit_object_type_flat(self,
> + name: str,
> + info: Optional[QAPISourceInfo],
> + ifcond: QAPISchemaIfCond,
> + features: List[QAPISchemaFeature],
> + members: List[QAPISchemaObjectTypeMember],
> + branches: Optional[QAPISchemaBranches]) ->
> None:
> + self._record(features)
> +
> + def visit_object_type(self,
> + name: str,
> + info: Optional[QAPISourceInfo],
> + ifcond: QAPISchemaIfCond,
> + features: List[QAPISchemaFeature],
> + base: Optional[QAPISchemaObjectType],
> + members: List[QAPISchemaObjectTypeMember],
> + branches: Optional[QAPISchemaBranches]) -> None:
> + self._record(features)
> +
> + def visit_alternate_type(self,
> + name: str,
> + info: Optional[QAPISourceInfo],
> + ifcond: QAPISchemaIfCond,
> + features: List[QAPISchemaFeature],
> + alternatives: QAPISchemaAlternatives) -> None:
> + self._record(features)
> +
> + def visit_command(self,
> + name: str,
> + info: Optional[QAPISourceInfo],
> + ifcond: QAPISchemaIfCond,
> + features: List[QAPISchemaFeature],
> + arg_type: Optional[QAPISchemaObjectType],
> + ret_type: Optional[QAPISchemaType],
> + gen: bool,
> + success_response: bool,
> + boxed: bool,
> + allow_oob: bool,
> + allow_preconfig: bool,
> + coroutine: bool) -> None:
> + self._record(features)
> +
> + def visit_event(self,
> + name: str,
> + info: Optional[QAPISourceInfo],
> + ifcond: QAPISchemaIfCond,
> + features: List[QAPISchemaFeature],
> + arg_type: Optional[QAPISchemaObjectType],
> + boxed: bool) -> None:
> + self._record(features)
> +
pycodestyle-3 gripes
scripts/qapi/features.py:129:1: E302 expected 2 blank lines, found 1
> +def gen_features(schema: QAPISchema,
> + output_dir: str,
> + prefix: str) -> None:
> + vis = QAPISchemaGenFeatureVisitor(prefix)
> + schema.visit(vis)
> + vis.write(output_dir)
We have another gen_features() in gen.py. Not a show stopper, but could
we find equally good names that don't clash?
> diff --git a/scripts/qapi/main.py b/scripts/qapi/main.py
> index 316736b6a2..2b9a2c0c02 100644
> --- a/scripts/qapi/main.py
> +++ b/scripts/qapi/main.py
> @@ -18,6 +18,7 @@
> from .introspect import gen_introspect
> from .schema import QAPISchema
> from .types import gen_types
> +from .features import gen_features
> from .visit import gen_visit
>
>
> @@ -49,6 +50,7 @@ def generate(schema_file: str,
>
> schema = QAPISchema(schema_file)
> gen_types(schema, output_dir, prefix, builtins)
> + gen_features(schema, output_dir, prefix)
> gen_visit(schema, output_dir, prefix, builtins)
> gen_commands(schema, output_dir, prefix, gen_tracing)
> gen_events(schema, output_dir, prefix)
> diff --git a/scripts/qapi/schema.py b/scripts/qapi/schema.py
> index d65c35f6ee..160ce0a7c0 100644
> --- a/scripts/qapi/schema.py
> +++ b/scripts/qapi/schema.py
> @@ -933,8 +933,11 @@ def connect_doc(self, doc: Optional[QAPIDoc]) -> None:
> class QAPISchemaFeature(QAPISchemaMember):
> role = 'feature'
>
> + # Features which are standardized across all schemas
> + SPECIAL_NAMES = ['deprecated', 'unstable']
> +
> def is_special(self) -> bool:
> - return self.name in ('deprecated', 'unstable')
> + return self.name in QAPISchemaFeature.SPECIAL_NAMES
>
>
> class QAPISchemaObjectTypeMember(QAPISchemaMember):
> diff --git a/scripts/qapi/types.py b/scripts/qapi/types.py
> index b2d26c2ea8..3435f1b0b0 100644
> --- a/scripts/qapi/types.py
> +++ b/scripts/qapi/types.py
> @@ -313,7 +313,9 @@ def _begin_user_module(self, name: str) -> None:
> types=types, visit=visit))
> self._genh.preamble_add(mcgen('''
> #include "qapi/qapi-builtin-types.h"
> -'''))
> +#include "%(prefix)sqapi-features.h"
This works, because it pulls in qapi-features.h basically everywhere.
It's actually needed only where we use enum QapiFeature. So far, we
only ever generate uses with gen.gen_features(). Callers:
* gen_register_command() for qapi-init-commands.c.
* gen_enum_lookup() for qapi-types*.c and qapi-emit-events.c.
* gen_visit_object_members() for qapi-visit*.c.
Please include it just in these generated .c files.
> +''',
> + prefix=self._prefix))
>
> def visit_begin(self, schema: QAPISchema) -> None:
> # gen_object() is recursive, ensure it doesn't visit the empty type
