Kevin Wolf <kw...@redhat.com> writes:
> Introduce alias definitions for object types (structs and unions). This
> allows using the same QAPI type and visitor for many syntax variations
> that exist in the external representation, like between QMP and the
> command line. It also provides a new tool for evolving the schema while
> maintaining backwards compatibility during a deprecation period.
>
> Signed-off-by: Kevin Wolf <kw...@redhat.com>
[...]
> diff --git a/scripts/qapi/visit.py b/scripts/qapi/visit.py
> index 22e62df901..e370485f6e 100644
> --- a/scripts/qapi/visit.py
> +++ b/scripts/qapi/visit.py
> @@ -26,6 +26,7 @@ from .common import (
> from .gen import QAPISchemaModularCVisitor, ifcontext
> from .schema import (
> QAPISchema,
> + QAPISchemaAlias,
> QAPISchemaEnumMember,
> QAPISchemaEnumType,
> QAPISchemaFeature,
> @@ -60,7 +61,8 @@ bool visit_type_%(c_name)s_members(Visitor *v, %(c_name)s
> *obj, Error **errp);
> def gen_visit_object_members(name: str,
> base: Optional[QAPISchemaObjectType],
> members: List[QAPISchemaObjectTypeMember],
> - variants: Optional[QAPISchemaVariants]) -> str:
> + variants: Optional[QAPISchemaVariants],
> + aliases: List[QAPISchemaAlias]) -> str:
> ret = mcgen('''
>
> bool visit_type_%(c_name)s_members(Visitor *v, %(c_name)s *obj, Error **errp)
> @@ -68,6 +70,24 @@ bool visit_type_%(c_name)s_members(Visitor *v, %(c_name)s
> *obj, Error **errp)
> ''',
> c_name=c_name(name))
>
> + if aliases:
> + ret += mcgen('''
> + visit_start_alias_scope(v);
> +''')
> +
> + for a in aliases:
> + if a.name:
> + name = '"%s"' % a.name
> + else:
> + name = "NULL"
> +
> + source = ", ".join('"%s"' % x for x in a.source)
> +
> + ret += mcgen('''
> + visit_define_alias(v, %(name)s, (const char * []) { %(source)s, NULL });
> +''',
> + name=name, source=source)
> +
> if base:
> ret += mcgen('''
> if (!visit_type_%(c_type)s_members(v, (%(c_type)s *)obj, errp)) {
> @@ -133,6 +153,11 @@ bool visit_type_%(c_name)s_members(Visitor *v,
> %(c_name)s *obj, Error **errp)
> }
> ''')
>
> + if aliases:
> + ret += mcgen('''
> + visit_end_alias_scope(v);
> +''')
> +
> ret += mcgen('''
> return true;
> }
The visit_type_FOO_members() are primarily helpers for the
visit_type_FOO(). But they also get called
* by visit_type_BAR_members() when
- struct or union BAR has 'base': 'FOO'
- union or alternate BAR a variant 'FOO'
* by qmp_marshal_CMD() when
- CMD has 'boxed': true, 'data': 'FOO'
Have you considered these cases?
How's the test coverage?
> @@ -361,14 +386,15 @@ class
> QAPISchemaGenVisitVisitor(QAPISchemaModularCVisitor):
> features: List[QAPISchemaFeature],
> base: Optional[QAPISchemaObjectType],
> members: List[QAPISchemaObjectTypeMember],
> - variants: Optional[QAPISchemaVariants]) -> None:
> + variants: Optional[QAPISchemaVariants],
> + aliases: List[QAPISchemaAlias]) -> None:
> # Nothing to do for the special empty builtin
> if name == 'q_empty':
> return
> with ifcontext(ifcond, self._genh, self._genc):
> self._genh.add(gen_visit_members_decl(name))
> - self._genc.add(gen_visit_object_members(name, base,
> - members, variants))
> + self._genc.add(gen_visit_object_members(
> + name, base, members, variants, aliases))
> # TODO Worth changing the visitor signature, so we could
> # directly use rather than repeat type.is_implicit()?
> if not name.startswith('q_'):
[...]
