Re: [RFC PATCH 07/12] qapi: Allow defining QOM classes

[Markus Armbruster <armbru@redhat.com>]

Kevin Wolf <kwolf@redhat.com> writes:

> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
> ---
>  scripts/qapi/expr.py   | 28 +++++++++++++++++-
>  scripts/qapi/schema.py | 66 ++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 93 insertions(+), 1 deletion(-)

Missing: docs/devel/qapi-code-gen.rst update.  I understand why, but it
does make review harder.

>
> diff --git a/scripts/qapi/expr.py b/scripts/qapi/expr.py
> index 3cb389e875..77550629f3 100644
> --- a/scripts/qapi/expr.py
> +++ b/scripts/qapi/expr.py
> @@ -181,6 +181,8 @@ def check_defn_name_str(name: str, info: QAPISourceInfo, meta: str) -> None:
>      """
>      if meta == 'event':
>          check_name_upper(name, info, meta)
> +    elif meta == 'class':
> +        check_name_str(name, info, meta)

This permits arbitrary QAPI names.  I figure we'll want to define and
enforce a suitable naming convention.

>      elif meta == 'command':
>          check_name_lower(
>              name, info, meta,
> @@ -557,6 +559,24 @@ def check_alternate(expr: _JSONObject, info: QAPISourceInfo) -> None:
>          check_type(value['type'], info, source)
>  
>  
> +def check_class(expr: _JSONObject, info: QAPISourceInfo) -> None:
> +    """
> +    Normalize and validate this expression as a ``class`` definition.
> +
> +    :param expr: The expression to validate.
> +    :param info: QAPI schema source file information.
> +
> +    :raise QAPISemError: When ``expr`` is not a valid ``class``.
> +    :return: None, ``expr`` is normalized in-place as needed.
> +    """
> +    config = expr.get('config')
> +    config_boxed = expr.get('config-boxed', False)
> +
> +    if config_boxed and config is None:
> +        raise QAPISemError(info, "'boxed': true requires 'config'")

You check 'config-boxed', but the error message talks about 'boxed'.

> +    check_type(config, info, "'config'", allow_dict=not config_boxed)
> +
> +
>  def check_command(expr: _JSONObject, info: QAPISourceInfo) -> None:
>      """
>      Normalize and validate this expression as a ``command`` definition.
> @@ -627,7 +647,7 @@ def check_exprs(exprs: List[_JSONObject]) -> List[_JSONObject]:
>              continue
>  
>          metas = expr.keys() & {'enum', 'struct', 'union', 'alternate',
> -                               'command', 'event'}
> +                               'class', 'command', 'event'}
>          if len(metas) != 1:
>              raise QAPISemError(
>                  info,
> @@ -671,6 +691,12 @@ def check_exprs(exprs: List[_JSONObject]) -> List[_JSONObject]:
>                         ['struct', 'data'], ['base', 'if', 'features'])
>              normalize_members(expr['data'])
>              check_struct(expr, info)
> +        elif meta == 'class':
> +            check_keys(expr, info, meta,
> +                       ['class'], ['if', 'features', 'parent', 'config',
> +                        'config-boxed'])
> +            normalize_members(expr.get('config'))
> +            check_class(expr, info)
>          elif meta == 'command':
>              check_keys(expr, info, meta,
>                         ['command'],
> diff --git a/scripts/qapi/schema.py b/scripts/qapi/schema.py
> index b7b3fc0ce4..ebf69341d7 100644
> --- a/scripts/qapi/schema.py
> +++ b/scripts/qapi/schema.py
> @@ -155,6 +155,9 @@ def visit_object_type_flat(self, name, info, ifcond, features,
>      def visit_alternate_type(self, name, info, ifcond, features, variants):
>          pass
>  
> +    def visit_class(self, entity):
> +        pass
> +
>      def visit_command(self, name, info, ifcond, features,
>                        arg_type, ret_type, gen, success_response, boxed,
>                        allow_oob, allow_preconfig, coroutine):
> @@ -766,6 +769,50 @@ def __init__(self, name, info, typ, ifcond=None):
>          super().__init__(name, info, typ, False, ifcond)
>  
>  
> +class QAPISchemaClass(QAPISchemaEntity):
> +    meta = 'class'
> +
> +    def __init__(self, name, info, doc, ifcond, features, parent,
> +                 config_type, config_boxed):
> +        super().__init__(name, info, doc, ifcond, features)
> +
> +        assert not parent or isinstance(parent, str)

I can't see what ensures this.

> +        assert not config_type or isinstance(config_type, str)
> +        self._parent_name = parent
> +        self.parent = None
> +        self._config_type_name = config_type
> +        self.config_type = None
> +        self.config_boxed = config_boxed
> +
> +    def check(self, schema):
> +        super().check(schema)
> +
> +        if self._parent_name:
> +            self.parent = schema.lookup_entity(self._parent_name,
> +                                               QAPISchemaClass)
> +            if not self.parent:
> +                raise QAPISemError(
> +                    self.info,
> +                    "Unknown parent class '%s'" % self._parent_name)
> +
> +        if self._config_type_name:
> +            self.config_type = schema.resolve_type(
> +                self._config_type_name, self.info, "class 'config'")

"class's 'config'" for consistency with other uses of .resolve_type().

> +            if not isinstance(self.config_type, QAPISchemaObjectType):
> +                raise QAPISemError(
> +                    self.info,
> +                    "class 'config' cannot take %s"
> +                    % self.config_type.describe())
> +            if self.config_type.variants and not self.boxed:

self.config_boxed?

> +                raise QAPISemError(
> +                    self.info,
> +                    "class 'config' can take %s only with 'boxed': true"

'config-boxed'?

> +                    % self.config_type.describe())
> +
> +    def visit(self, visitor):
> +        super().visit(visitor)
> +        visitor.visit_class(self)
> +
>  class QAPISchemaCommand(QAPISchemaEntity):
>      meta = 'command'
>  
> @@ -1110,6 +1157,23 @@ def _def_alternate_type(self, expr, info, doc):
>                                      QAPISchemaVariants(
>                                          None, info, tag_member, variants)))
>  
> +    def _def_class(self, expr, info, doc):
> +        name = expr['class']
> +        ifcond = QAPISchemaIfCond(expr.get('if'))
> +        features = self._make_features(expr.get('features'), info)
> +        parent = expr.get('parent')
> +        config_type = expr.get('config')
> +        config_boxed = expr.get('config-boxed')
> +
> +        if isinstance(config_type, OrderedDict):
> +            config_type = self._make_implicit_object_type(
> +                name, info, ifcond,
> +                'config', self._make_members(config_type, info))

Does QAPISchemaMember.describe() need an update for this?

> +
> +        self._def_entity(QAPISchemaClass(
> +            name, info, doc, ifcond, features, parent, config_type,
> +            config_boxed))
> +
>      def _def_command(self, expr, info, doc):
>          name = expr['command']
>          data = expr.get('data')
> @@ -1161,6 +1225,8 @@ def _def_exprs(self, exprs):
>                  self._def_union_type(expr, info, doc)
>              elif 'alternate' in expr:
>                  self._def_alternate_type(expr, info, doc)
> +            elif 'class' in expr:
> +                self._def_class(expr, info, doc)
>              elif 'command' in expr:
>                  self._def_command(expr, info, doc)
>              elif 'event' in expr: