xref: /openbmc/qemu/scripts/qapi/schema.py (revision a75b180f)
1# -*- coding: utf-8 -*-
2#
3# QAPI schema internal representation
4#
5# Copyright (c) 2015-2019 Red Hat Inc.
6#
7# Authors:
8#  Markus Armbruster <armbru@redhat.com>
9#  Eric Blake <eblake@redhat.com>
10#  Marc-André Lureau <marcandre.lureau@redhat.com>
11#
12# This work is licensed under the terms of the GNU GPL, version 2.
13# See the COPYING file in the top-level directory.
14
15# pylint: disable=too-many-lines
16
17# TODO catching name collisions in generated code would be nice
18
19from __future__ import annotations
20
21from abc import ABC, abstractmethod
22from collections import OrderedDict
23import os
24import re
25from typing import (
26    Any,
27    Callable,
28    Dict,
29    List,
30    Optional,
31    Union,
32    cast,
33)
34
35from .common import (
36    POINTER_SUFFIX,
37    c_name,
38    cgen_ifcond,
39    docgen_ifcond,
40    gen_endif,
41    gen_if,
42)
43from .error import QAPIError, QAPISemError, QAPISourceError
44from .expr import check_exprs
45from .parser import QAPIDoc, QAPIExpression, QAPISchemaParser
46from .source import QAPISourceInfo
47
48
49class QAPISchemaIfCond:
50    def __init__(
51        self,
52        ifcond: Optional[Union[str, Dict[str, object]]] = None,
53    ) -> None:
54        self.ifcond = ifcond
55
56    def _cgen(self) -> str:
57        return cgen_ifcond(self.ifcond)
58
59    def gen_if(self) -> str:
60        return gen_if(self._cgen())
61
62    def gen_endif(self) -> str:
63        return gen_endif(self._cgen())
64
65    def docgen(self) -> str:
66        return docgen_ifcond(self.ifcond)
67
68    def is_present(self) -> bool:
69        return bool(self.ifcond)
70
71
72class QAPISchemaEntity:
73    """
74    A schema entity.
75
76    This is either a directive, such as include, or a definition.
77    The latter uses sub-class `QAPISchemaDefinition`.
78    """
79    def __init__(self, info: Optional[QAPISourceInfo]):
80        self._module: Optional[QAPISchemaModule] = None
81        # For explicitly defined entities, info points to the (explicit)
82        # definition.  For builtins (and their arrays), info is None.
83        # For implicitly defined entities, info points to a place that
84        # triggered the implicit definition (there may be more than one
85        # such place).
86        self.info = info
87        self._checked = False
88
89    def __repr__(self) -> str:
90        return "<%s at 0x%x>" % (type(self).__name__, id(self))
91
92    def check(self, schema: QAPISchema) -> None:
93        # pylint: disable=unused-argument
94        self._checked = True
95
96    def connect_doc(self, doc: Optional[QAPIDoc] = None) -> None:
97        pass
98
99    def _set_module(
100        self, schema: QAPISchema, info: Optional[QAPISourceInfo]
101    ) -> None:
102        assert self._checked
103        fname = info.fname if info else QAPISchemaModule.BUILTIN_MODULE_NAME
104        self._module = schema.module_by_fname(fname)
105        self._module.add_entity(self)
106
107    def set_module(self, schema: QAPISchema) -> None:
108        self._set_module(schema, self.info)
109
110    def visit(self, visitor: QAPISchemaVisitor) -> None:
111        # pylint: disable=unused-argument
112        assert self._checked
113
114
115class QAPISchemaDefinition(QAPISchemaEntity):
116    meta: str
117
118    def __init__(
119        self,
120        name: str,
121        info: Optional[QAPISourceInfo],
122        doc: Optional[QAPIDoc],
123        ifcond: Optional[QAPISchemaIfCond] = None,
124        features: Optional[List[QAPISchemaFeature]] = None,
125    ):
126        super().__init__(info)
127        for f in features or []:
128            f.set_defined_in(name)
129        self.name = name
130        self.doc = doc
131        self._ifcond = ifcond or QAPISchemaIfCond()
132        self.features = features or []
133
134    def __repr__(self) -> str:
135        return "<%s:%s at 0x%x>" % (type(self).__name__, self.name,
136                                    id(self))
137
138    def c_name(self) -> str:
139        return c_name(self.name)
140
141    def check(self, schema: QAPISchema) -> None:
142        assert not self._checked
143        super().check(schema)
144        seen: Dict[str, QAPISchemaMember] = {}
145        for f in self.features:
146            f.check_clash(self.info, seen)
147
148    def connect_doc(self, doc: Optional[QAPIDoc] = None) -> None:
149        super().connect_doc(doc)
150        doc = doc or self.doc
151        if doc:
152            for f in self.features:
153                doc.connect_feature(f)
154
155    @property
156    def ifcond(self) -> QAPISchemaIfCond:
157        assert self._checked
158        return self._ifcond
159
160    def is_implicit(self) -> bool:
161        return not self.info
162
163    def describe(self) -> str:
164        return "%s '%s'" % (self.meta, self.name)
165
166
167class QAPISchemaVisitor:
168    def visit_begin(self, schema: QAPISchema) -> None:
169        pass
170
171    def visit_end(self) -> None:
172        pass
173
174    def visit_module(self, name: str) -> None:
175        pass
176
177    def visit_needed(self, entity: QAPISchemaEntity) -> bool:
178        # pylint: disable=unused-argument
179        # Default to visiting everything
180        return True
181
182    def visit_include(self, name: str, info: Optional[QAPISourceInfo]) -> None:
183        pass
184
185    def visit_builtin_type(
186        self, name: str, info: Optional[QAPISourceInfo], json_type: str
187    ) -> None:
188        pass
189
190    def visit_enum_type(
191        self,
192        name: str,
193        info: Optional[QAPISourceInfo],
194        ifcond: QAPISchemaIfCond,
195        features: List[QAPISchemaFeature],
196        members: List[QAPISchemaEnumMember],
197        prefix: Optional[str],
198    ) -> None:
199        pass
200
201    def visit_array_type(
202        self,
203        name: str,
204        info: Optional[QAPISourceInfo],
205        ifcond: QAPISchemaIfCond,
206        element_type: QAPISchemaType,
207    ) -> None:
208        pass
209
210    def visit_object_type(
211        self,
212        name: str,
213        info: Optional[QAPISourceInfo],
214        ifcond: QAPISchemaIfCond,
215        features: List[QAPISchemaFeature],
216        base: Optional[QAPISchemaObjectType],
217        members: List[QAPISchemaObjectTypeMember],
218        variants: Optional[QAPISchemaVariants],
219    ) -> None:
220        pass
221
222    def visit_object_type_flat(
223        self,
224        name: str,
225        info: Optional[QAPISourceInfo],
226        ifcond: QAPISchemaIfCond,
227        features: List[QAPISchemaFeature],
228        members: List[QAPISchemaObjectTypeMember],
229        variants: Optional[QAPISchemaVariants],
230    ) -> None:
231        pass
232
233    def visit_alternate_type(
234        self,
235        name: str,
236        info: Optional[QAPISourceInfo],
237        ifcond: QAPISchemaIfCond,
238        features: List[QAPISchemaFeature],
239        variants: QAPISchemaVariants,
240    ) -> None:
241        pass
242
243    def visit_command(
244        self,
245        name: str,
246        info: Optional[QAPISourceInfo],
247        ifcond: QAPISchemaIfCond,
248        features: List[QAPISchemaFeature],
249        arg_type: Optional[QAPISchemaObjectType],
250        ret_type: Optional[QAPISchemaType],
251        gen: bool,
252        success_response: bool,
253        boxed: bool,
254        allow_oob: bool,
255        allow_preconfig: bool,
256        coroutine: bool,
257    ) -> None:
258        pass
259
260    def visit_event(
261        self,
262        name: str,
263        info: Optional[QAPISourceInfo],
264        ifcond: QAPISchemaIfCond,
265        features: List[QAPISchemaFeature],
266        arg_type: Optional[QAPISchemaObjectType],
267        boxed: bool,
268    ) -> None:
269        pass
270
271
272class QAPISchemaModule:
273
274    BUILTIN_MODULE_NAME = './builtin'
275
276    def __init__(self, name: str):
277        self.name = name
278        self._entity_list: List[QAPISchemaEntity] = []
279
280    @staticmethod
281    def is_system_module(name: str) -> bool:
282        """
283        System modules are internally defined modules.
284
285        Their names start with the "./" prefix.
286        """
287        return name.startswith('./')
288
289    @classmethod
290    def is_user_module(cls, name: str) -> bool:
291        """
292        User modules are those defined by the user in qapi JSON files.
293
294        They do not start with the "./" prefix.
295        """
296        return not cls.is_system_module(name)
297
298    @classmethod
299    def is_builtin_module(cls, name: str) -> bool:
300        """
301        The built-in module is a single System module for the built-in types.
302
303        It is always "./builtin".
304        """
305        return name == cls.BUILTIN_MODULE_NAME
306
307    def add_entity(self, ent: QAPISchemaEntity) -> None:
308        self._entity_list.append(ent)
309
310    def visit(self, visitor: QAPISchemaVisitor) -> None:
311        visitor.visit_module(self.name)
312        for entity in self._entity_list:
313            if visitor.visit_needed(entity):
314                entity.visit(visitor)
315
316
317class QAPISchemaInclude(QAPISchemaEntity):
318    def __init__(self, sub_module: QAPISchemaModule, info: QAPISourceInfo):
319        super().__init__(info)
320        self._sub_module = sub_module
321
322    def visit(self, visitor: QAPISchemaVisitor) -> None:
323        super().visit(visitor)
324        visitor.visit_include(self._sub_module.name, self.info)
325
326
327class QAPISchemaType(QAPISchemaDefinition, ABC):
328    # Return the C type for common use.
329    # For the types we commonly box, this is a pointer type.
330    @abstractmethod
331    def c_type(self) -> str:
332        pass
333
334    # Return the C type to be used in a parameter list.
335    def c_param_type(self) -> str:
336        return self.c_type()
337
338    # Return the C type to be used where we suppress boxing.
339    def c_unboxed_type(self) -> str:
340        return self.c_type()
341
342    @abstractmethod
343    def json_type(self) -> str:
344        pass
345
346    def alternate_qtype(self) -> Optional[str]:
347        json2qtype = {
348            'null':    'QTYPE_QNULL',
349            'string':  'QTYPE_QSTRING',
350            'number':  'QTYPE_QNUM',
351            'int':     'QTYPE_QNUM',
352            'boolean': 'QTYPE_QBOOL',
353            'array':   'QTYPE_QLIST',
354            'object':  'QTYPE_QDICT'
355        }
356        return json2qtype.get(self.json_type())
357
358    def doc_type(self) -> Optional[str]:
359        if self.is_implicit():
360            return None
361        return self.name
362
363    def need_has_if_optional(self) -> bool:
364        # When FOO is a pointer, has_FOO == !!FOO, i.e. has_FOO is redundant.
365        # Except for arrays; see QAPISchemaArrayType.need_has_if_optional().
366        return not self.c_type().endswith(POINTER_SUFFIX)
367
368    def check(self, schema: QAPISchema) -> None:
369        super().check(schema)
370        for feat in self.features:
371            if feat.is_special():
372                raise QAPISemError(
373                    self.info,
374                    f"feature '{feat.name}' is not supported for types")
375
376    def describe(self) -> str:
377        return "%s type '%s'" % (self.meta, self.name)
378
379
380class QAPISchemaBuiltinType(QAPISchemaType):
381    meta = 'built-in'
382
383    def __init__(self, name: str, json_type: str, c_type: str):
384        super().__init__(name, None, None)
385        assert json_type in ('string', 'number', 'int', 'boolean', 'null',
386                             'value')
387        self._json_type_name = json_type
388        self._c_type_name = c_type
389
390    def c_name(self) -> str:
391        return self.name
392
393    def c_type(self) -> str:
394        return self._c_type_name
395
396    def c_param_type(self) -> str:
397        if self.name == 'str':
398            return 'const ' + self._c_type_name
399        return self._c_type_name
400
401    def json_type(self) -> str:
402        return self._json_type_name
403
404    def doc_type(self) -> str:
405        return self.json_type()
406
407    def visit(self, visitor: QAPISchemaVisitor) -> None:
408        super().visit(visitor)
409        visitor.visit_builtin_type(self.name, self.info, self.json_type())
410
411
412class QAPISchemaEnumType(QAPISchemaType):
413    meta = 'enum'
414
415    def __init__(
416        self,
417        name: str,
418        info: Optional[QAPISourceInfo],
419        doc: Optional[QAPIDoc],
420        ifcond: Optional[QAPISchemaIfCond],
421        features: Optional[List[QAPISchemaFeature]],
422        members: List[QAPISchemaEnumMember],
423        prefix: Optional[str],
424    ):
425        super().__init__(name, info, doc, ifcond, features)
426        for m in members:
427            m.set_defined_in(name)
428        self.members = members
429        self.prefix = prefix
430
431    def check(self, schema: QAPISchema) -> None:
432        super().check(schema)
433        seen: Dict[str, QAPISchemaMember] = {}
434        for m in self.members:
435            m.check_clash(self.info, seen)
436
437    def connect_doc(self, doc: Optional[QAPIDoc] = None) -> None:
438        super().connect_doc(doc)
439        doc = doc or self.doc
440        for m in self.members:
441            m.connect_doc(doc)
442
443    def is_implicit(self) -> bool:
444        # See QAPISchema._def_predefineds()
445        return self.name == 'QType'
446
447    def c_type(self) -> str:
448        return c_name(self.name)
449
450    def member_names(self) -> List[str]:
451        return [m.name for m in self.members]
452
453    def json_type(self) -> str:
454        return 'string'
455
456    def visit(self, visitor: QAPISchemaVisitor) -> None:
457        super().visit(visitor)
458        visitor.visit_enum_type(
459            self.name, self.info, self.ifcond, self.features,
460            self.members, self.prefix)
461
462
463class QAPISchemaArrayType(QAPISchemaType):
464    meta = 'array'
465
466    def __init__(
467        self, name: str, info: Optional[QAPISourceInfo], element_type: str
468    ):
469        super().__init__(name, info, None)
470        self._element_type_name = element_type
471        self.element_type: QAPISchemaType
472
473    def need_has_if_optional(self) -> bool:
474        # When FOO is an array, we still need has_FOO to distinguish
475        # absent (!has_FOO) from present and empty (has_FOO && !FOO).
476        return True
477
478    def check(self, schema: QAPISchema) -> None:
479        super().check(schema)
480        self.element_type = schema.resolve_type(
481            self._element_type_name, self.info,
482            self.info.defn_meta if self.info else None)
483        assert not isinstance(self.element_type, QAPISchemaArrayType)
484
485    def set_module(self, schema: QAPISchema) -> None:
486        self._set_module(schema, self.element_type.info)
487
488    @property
489    def ifcond(self) -> QAPISchemaIfCond:
490        assert self._checked
491        return self.element_type.ifcond
492
493    def is_implicit(self) -> bool:
494        return True
495
496    def c_type(self) -> str:
497        return c_name(self.name) + POINTER_SUFFIX
498
499    def json_type(self) -> str:
500        return 'array'
501
502    def doc_type(self) -> Optional[str]:
503        elt_doc_type = self.element_type.doc_type()
504        if not elt_doc_type:
505            return None
506        return 'array of ' + elt_doc_type
507
508    def visit(self, visitor: QAPISchemaVisitor) -> None:
509        super().visit(visitor)
510        visitor.visit_array_type(self.name, self.info, self.ifcond,
511                                 self.element_type)
512
513    def describe(self) -> str:
514        return "%s type ['%s']" % (self.meta, self._element_type_name)
515
516
517class QAPISchemaObjectType(QAPISchemaType):
518    def __init__(
519        self,
520        name: str,
521        info: Optional[QAPISourceInfo],
522        doc: Optional[QAPIDoc],
523        ifcond: Optional[QAPISchemaIfCond],
524        features: Optional[List[QAPISchemaFeature]],
525        base: Optional[str],
526        local_members: List[QAPISchemaObjectTypeMember],
527        variants: Optional[QAPISchemaVariants],
528    ):
529        # struct has local_members, optional base, and no variants
530        # union has base, variants, and no local_members
531        super().__init__(name, info, doc, ifcond, features)
532        self.meta = 'union' if variants else 'struct'
533        for m in local_members:
534            m.set_defined_in(name)
535        if variants is not None:
536            variants.set_defined_in(name)
537        self._base_name = base
538        self.base = None
539        self.local_members = local_members
540        self.variants = variants
541        self.members: List[QAPISchemaObjectTypeMember]
542        self._check_complete = False
543
544    def check(self, schema: QAPISchema) -> None:
545        # This calls another type T's .check() exactly when the C
546        # struct emitted by gen_object() contains that T's C struct
547        # (pointers don't count).
548        if self._check_complete:
549            # A previous .check() completed: nothing to do
550            return
551        if self._checked:
552            # Recursed: C struct contains itself
553            raise QAPISemError(self.info,
554                               "object %s contains itself" % self.name)
555
556        super().check(schema)
557        assert self._checked and not self._check_complete
558
559        seen = OrderedDict()
560        if self._base_name:
561            self.base = schema.resolve_type(self._base_name, self.info,
562                                            "'base'")
563            if (not isinstance(self.base, QAPISchemaObjectType)
564                    or self.base.variants):
565                raise QAPISemError(
566                    self.info,
567                    "'base' requires a struct type, %s isn't"
568                    % self.base.describe())
569            self.base.check(schema)
570            self.base.check_clash(self.info, seen)
571        for m in self.local_members:
572            m.check(schema)
573            m.check_clash(self.info, seen)
574
575        # self.check_clash() works in terms of the supertype, but
576        # self.members is declared List[QAPISchemaObjectTypeMember].
577        # Cast down to the subtype.
578        members = cast(List[QAPISchemaObjectTypeMember], list(seen.values()))
579
580        if self.variants:
581            self.variants.check(schema, seen)
582            self.variants.check_clash(self.info, seen)
583
584        self.members = members
585        self._check_complete = True  # mark completed
586
587    # Check that the members of this type do not cause duplicate JSON members,
588    # and update seen to track the members seen so far. Report any errors
589    # on behalf of info, which is not necessarily self.info
590    def check_clash(
591        self,
592        info: Optional[QAPISourceInfo],
593        seen: Dict[str, QAPISchemaMember],
594    ) -> None:
595        assert self._checked
596        for m in self.members:
597            m.check_clash(info, seen)
598        if self.variants:
599            self.variants.check_clash(info, seen)
600
601    def connect_doc(self, doc: Optional[QAPIDoc] = None) -> None:
602        super().connect_doc(doc)
603        doc = doc or self.doc
604        if self.base and self.base.is_implicit():
605            self.base.connect_doc(doc)
606        for m in self.local_members:
607            m.connect_doc(doc)
608
609    def is_implicit(self) -> bool:
610        # See QAPISchema._make_implicit_object_type(), as well as
611        # _def_predefineds()
612        return self.name.startswith('q_')
613
614    def is_empty(self) -> bool:
615        return not self.members and not self.variants
616
617    def has_conditional_members(self) -> bool:
618        return any(m.ifcond.is_present() for m in self.members)
619
620    def c_name(self) -> str:
621        assert self.name != 'q_empty'
622        return super().c_name()
623
624    def c_type(self) -> str:
625        assert not self.is_implicit()
626        return c_name(self.name) + POINTER_SUFFIX
627
628    def c_unboxed_type(self) -> str:
629        return c_name(self.name)
630
631    def json_type(self) -> str:
632        return 'object'
633
634    def visit(self, visitor: QAPISchemaVisitor) -> None:
635        super().visit(visitor)
636        visitor.visit_object_type(
637            self.name, self.info, self.ifcond, self.features,
638            self.base, self.local_members, self.variants)
639        visitor.visit_object_type_flat(
640            self.name, self.info, self.ifcond, self.features,
641            self.members, self.variants)
642
643
644class QAPISchemaAlternateType(QAPISchemaType):
645    meta = 'alternate'
646
647    def __init__(
648        self,
649        name: str,
650        info: QAPISourceInfo,
651        doc: Optional[QAPIDoc],
652        ifcond: Optional[QAPISchemaIfCond],
653        features: List[QAPISchemaFeature],
654        variants: QAPISchemaVariants,
655    ):
656        super().__init__(name, info, doc, ifcond, features)
657        assert variants.tag_member
658        variants.set_defined_in(name)
659        variants.tag_member.set_defined_in(self.name)
660        self.variants = variants
661
662    def check(self, schema: QAPISchema) -> None:
663        super().check(schema)
664        self.variants.tag_member.check(schema)
665        # Not calling self.variants.check_clash(), because there's nothing
666        # to clash with
667        self.variants.check(schema, {})
668        # Alternate branch names have no relation to the tag enum values;
669        # so we have to check for potential name collisions ourselves.
670        seen: Dict[str, QAPISchemaMember] = {}
671        types_seen: Dict[str, str] = {}
672        for v in self.variants.variants:
673            v.check_clash(self.info, seen)
674            qtype = v.type.alternate_qtype()
675            if not qtype:
676                raise QAPISemError(
677                    self.info,
678                    "%s cannot use %s"
679                    % (v.describe(self.info), v.type.describe()))
680            conflicting = set([qtype])
681            if qtype == 'QTYPE_QSTRING':
682                if isinstance(v.type, QAPISchemaEnumType):
683                    for m in v.type.members:
684                        if m.name in ['on', 'off']:
685                            conflicting.add('QTYPE_QBOOL')
686                        if re.match(r'[-+0-9.]', m.name):
687                            # lazy, could be tightened
688                            conflicting.add('QTYPE_QNUM')
689                else:
690                    conflicting.add('QTYPE_QNUM')
691                    conflicting.add('QTYPE_QBOOL')
692            for qt in conflicting:
693                if qt in types_seen:
694                    raise QAPISemError(
695                        self.info,
696                        "%s can't be distinguished from '%s'"
697                        % (v.describe(self.info), types_seen[qt]))
698                types_seen[qt] = v.name
699
700    def connect_doc(self, doc: Optional[QAPIDoc] = None) -> None:
701        super().connect_doc(doc)
702        doc = doc or self.doc
703        for v in self.variants.variants:
704            v.connect_doc(doc)
705
706    def c_type(self) -> str:
707        return c_name(self.name) + POINTER_SUFFIX
708
709    def json_type(self) -> str:
710        return 'value'
711
712    def visit(self, visitor: QAPISchemaVisitor) -> None:
713        super().visit(visitor)
714        visitor.visit_alternate_type(
715            self.name, self.info, self.ifcond, self.features, self.variants)
716
717
718class QAPISchemaVariants:
719    def __init__(
720        self,
721        tag_name: Optional[str],
722        info: QAPISourceInfo,
723        tag_member: Optional[QAPISchemaObjectTypeMember],
724        variants: List[QAPISchemaVariant],
725    ):
726        # Unions pass tag_name but not tag_member.
727        # Alternates pass tag_member but not tag_name.
728        # After check(), tag_member is always set.
729        assert bool(tag_member) != bool(tag_name)
730        assert (isinstance(tag_name, str) or
731                isinstance(tag_member, QAPISchemaObjectTypeMember))
732        self._tag_name = tag_name
733        self.info = info
734        self._tag_member = tag_member
735        self.variants = variants
736
737    @property
738    def tag_member(self) -> QAPISchemaObjectTypeMember:
739        if self._tag_member is None:
740            raise RuntimeError(
741                "QAPISchemaVariants has no tag_member property until "
742                "after check() has been run."
743            )
744        return self._tag_member
745
746    def set_defined_in(self, name: str) -> None:
747        for v in self.variants:
748            v.set_defined_in(name)
749
750    def check(
751        self, schema: QAPISchema, seen: Dict[str, QAPISchemaMember]
752    ) -> None:
753        if self._tag_name:      # union
754            # We need to narrow the member type:
755            tmp = seen.get(c_name(self._tag_name))
756            assert tmp is None or isinstance(tmp, QAPISchemaObjectTypeMember)
757            self._tag_member = tmp
758
759            base = "'base'"
760            # Pointing to the base type when not implicit would be
761            # nice, but we don't know it here
762            if not self._tag_member or self._tag_name != self._tag_member.name:
763                raise QAPISemError(
764                    self.info,
765                    "discriminator '%s' is not a member of %s"
766                    % (self._tag_name, base))
767            # Here we do:
768            assert self.tag_member.defined_in
769            base_type = schema.lookup_type(self.tag_member.defined_in)
770            assert base_type
771            if not base_type.is_implicit():
772                base = "base type '%s'" % self.tag_member.defined_in
773            if not isinstance(self.tag_member.type, QAPISchemaEnumType):
774                raise QAPISemError(
775                    self.info,
776                    "discriminator member '%s' of %s must be of enum type"
777                    % (self._tag_name, base))
778            if self.tag_member.optional:
779                raise QAPISemError(
780                    self.info,
781                    "discriminator member '%s' of %s must not be optional"
782                    % (self._tag_name, base))
783            if self.tag_member.ifcond.is_present():
784                raise QAPISemError(
785                    self.info,
786                    "discriminator member '%s' of %s must not be conditional"
787                    % (self._tag_name, base))
788        else:                   # alternate
789            assert self._tag_member
790            assert isinstance(self.tag_member.type, QAPISchemaEnumType)
791            assert not self.tag_member.optional
792            assert not self.tag_member.ifcond.is_present()
793        if self._tag_name:      # union
794            # branches that are not explicitly covered get an empty type
795            assert self.tag_member.defined_in
796            cases = {v.name for v in self.variants}
797            for m in self.tag_member.type.members:
798                if m.name not in cases:
799                    v = QAPISchemaVariant(m.name, self.info,
800                                          'q_empty', m.ifcond)
801                    v.set_defined_in(self.tag_member.defined_in)
802                    self.variants.append(v)
803        if not self.variants:
804            raise QAPISemError(self.info, "union has no branches")
805        for v in self.variants:
806            v.check(schema)
807            # Union names must match enum values; alternate names are
808            # checked separately. Use 'seen' to tell the two apart.
809            if seen:
810                if v.name not in self.tag_member.type.member_names():
811                    raise QAPISemError(
812                        self.info,
813                        "branch '%s' is not a value of %s"
814                        % (v.name, self.tag_member.type.describe()))
815                if not isinstance(v.type, QAPISchemaObjectType):
816                    raise QAPISemError(
817                        self.info,
818                        "%s cannot use %s"
819                        % (v.describe(self.info), v.type.describe()))
820                v.type.check(schema)
821
822    def check_clash(
823        self,
824        info: Optional[QAPISourceInfo],
825        seen: Dict[str, QAPISchemaMember],
826    ) -> None:
827        for v in self.variants:
828            # Reset seen map for each variant, since qapi names from one
829            # branch do not affect another branch.
830            #
831            # v.type's typing is enforced in check() above.
832            assert isinstance(v.type, QAPISchemaObjectType)
833            v.type.check_clash(info, dict(seen))
834
835
836class QAPISchemaMember:
837    """ Represents object members, enum members and features """
838    role = 'member'
839
840    def __init__(
841        self,
842        name: str,
843        info: Optional[QAPISourceInfo],
844        ifcond: Optional[QAPISchemaIfCond] = None,
845    ):
846        self.name = name
847        self.info = info
848        self.ifcond = ifcond or QAPISchemaIfCond()
849        self.defined_in: Optional[str] = None
850
851    def set_defined_in(self, name: str) -> None:
852        assert not self.defined_in
853        self.defined_in = name
854
855    def check_clash(
856        self,
857        info: Optional[QAPISourceInfo],
858        seen: Dict[str, QAPISchemaMember],
859    ) -> None:
860        cname = c_name(self.name)
861        if cname in seen:
862            raise QAPISemError(
863                info,
864                "%s collides with %s"
865                % (self.describe(info), seen[cname].describe(info)))
866        seen[cname] = self
867
868    def connect_doc(self, doc: Optional[QAPIDoc]) -> None:
869        if doc:
870            doc.connect_member(self)
871
872    def describe(self, info: Optional[QAPISourceInfo]) -> str:
873        role = self.role
874        meta = 'type'
875        defined_in = self.defined_in
876        assert defined_in
877
878        if defined_in.startswith('q_obj_'):
879            # See QAPISchema._make_implicit_object_type() - reverse the
880            # mapping there to create a nice human-readable description
881            defined_in = defined_in[6:]
882            if defined_in.endswith('-arg'):
883                # Implicit type created for a command's dict 'data'
884                assert role == 'member'
885                role = 'parameter'
886                meta = 'command'
887                defined_in = defined_in[:-4]
888            elif defined_in.endswith('-base'):
889                # Implicit type created for a union's dict 'base'
890                role = 'base ' + role
891                defined_in = defined_in[:-5]
892            else:
893                assert False
894
895        assert info is not None
896        if defined_in != info.defn_name:
897            return "%s '%s' of %s '%s'" % (role, self.name, meta, defined_in)
898        return "%s '%s'" % (role, self.name)
899
900
901class QAPISchemaEnumMember(QAPISchemaMember):
902    role = 'value'
903
904    def __init__(
905        self,
906        name: str,
907        info: Optional[QAPISourceInfo],
908        ifcond: Optional[QAPISchemaIfCond] = None,
909        features: Optional[List[QAPISchemaFeature]] = None,
910    ):
911        super().__init__(name, info, ifcond)
912        for f in features or []:
913            f.set_defined_in(name)
914        self.features = features or []
915
916    def connect_doc(self, doc: Optional[QAPIDoc]) -> None:
917        super().connect_doc(doc)
918        if doc:
919            for f in self.features:
920                doc.connect_feature(f)
921
922
923class QAPISchemaFeature(QAPISchemaMember):
924    role = 'feature'
925
926    def is_special(self) -> bool:
927        return self.name in ('deprecated', 'unstable')
928
929
930class QAPISchemaObjectTypeMember(QAPISchemaMember):
931    def __init__(
932        self,
933        name: str,
934        info: QAPISourceInfo,
935        typ: str,
936        optional: bool,
937        ifcond: Optional[QAPISchemaIfCond] = None,
938        features: Optional[List[QAPISchemaFeature]] = None,
939    ):
940        super().__init__(name, info, ifcond)
941        for f in features or []:
942            f.set_defined_in(name)
943        self._type_name = typ
944        self.type: QAPISchemaType  # set during check()
945        self.optional = optional
946        self.features = features or []
947
948    def need_has(self) -> bool:
949        return self.optional and self.type.need_has_if_optional()
950
951    def check(self, schema: QAPISchema) -> None:
952        assert self.defined_in
953        self.type = schema.resolve_type(self._type_name, self.info,
954                                        self.describe)
955        seen: Dict[str, QAPISchemaMember] = {}
956        for f in self.features:
957            f.check_clash(self.info, seen)
958
959    def connect_doc(self, doc: Optional[QAPIDoc]) -> None:
960        super().connect_doc(doc)
961        if doc:
962            for f in self.features:
963                doc.connect_feature(f)
964
965
966class QAPISchemaVariant(QAPISchemaObjectTypeMember):
967    role = 'branch'
968
969    def __init__(
970        self,
971        name: str,
972        info: QAPISourceInfo,
973        typ: str,
974        ifcond: QAPISchemaIfCond,
975    ):
976        super().__init__(name, info, typ, False, ifcond)
977
978
979class QAPISchemaCommand(QAPISchemaDefinition):
980    meta = 'command'
981
982    def __init__(
983        self,
984        name: str,
985        info: QAPISourceInfo,
986        doc: Optional[QAPIDoc],
987        ifcond: QAPISchemaIfCond,
988        features: List[QAPISchemaFeature],
989        arg_type: Optional[str],
990        ret_type: Optional[str],
991        gen: bool,
992        success_response: bool,
993        boxed: bool,
994        allow_oob: bool,
995        allow_preconfig: bool,
996        coroutine: bool,
997    ):
998        super().__init__(name, info, doc, ifcond, features)
999        self._arg_type_name = arg_type
1000        self.arg_type: Optional[QAPISchemaObjectType] = None
1001        self._ret_type_name = ret_type
1002        self.ret_type: Optional[QAPISchemaType] = None
1003        self.gen = gen
1004        self.success_response = success_response
1005        self.boxed = boxed
1006        self.allow_oob = allow_oob
1007        self.allow_preconfig = allow_preconfig
1008        self.coroutine = coroutine
1009
1010    def check(self, schema: QAPISchema) -> None:
1011        assert self.info is not None
1012        super().check(schema)
1013        if self._arg_type_name:
1014            arg_type = schema.resolve_type(
1015                self._arg_type_name, self.info, "command's 'data'")
1016            if not isinstance(arg_type, QAPISchemaObjectType):
1017                raise QAPISemError(
1018                    self.info,
1019                    "command's 'data' cannot take %s"
1020                    % arg_type.describe())
1021            self.arg_type = arg_type
1022            if self.arg_type.variants and not self.boxed:
1023                raise QAPISemError(
1024                    self.info,
1025                    "command's 'data' can take %s only with 'boxed': true"
1026                    % self.arg_type.describe())
1027            self.arg_type.check(schema)
1028            if self.arg_type.has_conditional_members() and not self.boxed:
1029                raise QAPISemError(
1030                    self.info,
1031                    "conditional command arguments require 'boxed': true")
1032        if self._ret_type_name:
1033            self.ret_type = schema.resolve_type(
1034                self._ret_type_name, self.info, "command's 'returns'")
1035            if self.name not in self.info.pragma.command_returns_exceptions:
1036                typ = self.ret_type
1037                if isinstance(typ, QAPISchemaArrayType):
1038                    typ = typ.element_type
1039                if not isinstance(typ, QAPISchemaObjectType):
1040                    raise QAPISemError(
1041                        self.info,
1042                        "command's 'returns' cannot take %s"
1043                        % self.ret_type.describe())
1044
1045    def connect_doc(self, doc: Optional[QAPIDoc] = None) -> None:
1046        super().connect_doc(doc)
1047        doc = doc or self.doc
1048        if doc:
1049            if self.arg_type and self.arg_type.is_implicit():
1050                self.arg_type.connect_doc(doc)
1051
1052    def visit(self, visitor: QAPISchemaVisitor) -> None:
1053        super().visit(visitor)
1054        visitor.visit_command(
1055            self.name, self.info, self.ifcond, self.features,
1056            self.arg_type, self.ret_type, self.gen, self.success_response,
1057            self.boxed, self.allow_oob, self.allow_preconfig,
1058            self.coroutine)
1059
1060
1061class QAPISchemaEvent(QAPISchemaDefinition):
1062    meta = 'event'
1063
1064    def __init__(
1065        self,
1066        name: str,
1067        info: QAPISourceInfo,
1068        doc: Optional[QAPIDoc],
1069        ifcond: QAPISchemaIfCond,
1070        features: List[QAPISchemaFeature],
1071        arg_type: Optional[str],
1072        boxed: bool,
1073    ):
1074        super().__init__(name, info, doc, ifcond, features)
1075        self._arg_type_name = arg_type
1076        self.arg_type: Optional[QAPISchemaObjectType] = None
1077        self.boxed = boxed
1078
1079    def check(self, schema: QAPISchema) -> None:
1080        super().check(schema)
1081        if self._arg_type_name:
1082            typ = schema.resolve_type(
1083                self._arg_type_name, self.info, "event's 'data'")
1084            if not isinstance(typ, QAPISchemaObjectType):
1085                raise QAPISemError(
1086                    self.info,
1087                    "event's 'data' cannot take %s"
1088                    % typ.describe())
1089            self.arg_type = typ
1090            if self.arg_type.variants and not self.boxed:
1091                raise QAPISemError(
1092                    self.info,
1093                    "event's 'data' can take %s only with 'boxed': true"
1094                    % self.arg_type.describe())
1095            self.arg_type.check(schema)
1096            if self.arg_type.has_conditional_members() and not self.boxed:
1097                raise QAPISemError(
1098                    self.info,
1099                    "conditional event arguments require 'boxed': true")
1100
1101    def connect_doc(self, doc: Optional[QAPIDoc] = None) -> None:
1102        super().connect_doc(doc)
1103        doc = doc or self.doc
1104        if doc:
1105            if self.arg_type and self.arg_type.is_implicit():
1106                self.arg_type.connect_doc(doc)
1107
1108    def visit(self, visitor: QAPISchemaVisitor) -> None:
1109        super().visit(visitor)
1110        visitor.visit_event(
1111            self.name, self.info, self.ifcond, self.features,
1112            self.arg_type, self.boxed)
1113
1114
1115class QAPISchema:
1116    def __init__(self, fname: str):
1117        self.fname = fname
1118
1119        try:
1120            parser = QAPISchemaParser(fname)
1121        except OSError as err:
1122            raise QAPIError(
1123                f"can't read schema file '{fname}': {err.strerror}"
1124            ) from err
1125
1126        exprs = check_exprs(parser.exprs)
1127        self.docs = parser.docs
1128        self._entity_list: List[QAPISchemaEntity] = []
1129        self._entity_dict: Dict[str, QAPISchemaDefinition] = {}
1130        self._module_dict: Dict[str, QAPISchemaModule] = OrderedDict()
1131        self._schema_dir = os.path.dirname(fname)
1132        self._make_module(QAPISchemaModule.BUILTIN_MODULE_NAME)
1133        self._make_module(fname)
1134        self._predefining = True
1135        self._def_predefineds()
1136        self._predefining = False
1137        self._def_exprs(exprs)
1138        self.check()
1139
1140    def _def_entity(self, ent: QAPISchemaEntity) -> None:
1141        self._entity_list.append(ent)
1142
1143    def _def_definition(self, defn: QAPISchemaDefinition) -> None:
1144        # Only the predefined types are allowed to not have info
1145        assert defn.info or self._predefining
1146        self._def_entity(defn)
1147        # TODO reject names that differ only in '_' vs. '.'  vs. '-',
1148        # because they're liable to clash in generated C.
1149        other_defn = self._entity_dict.get(defn.name)
1150        if other_defn:
1151            if other_defn.info:
1152                where = QAPISourceError(other_defn.info, "previous definition")
1153                raise QAPISemError(
1154                    defn.info,
1155                    "'%s' is already defined\n%s" % (defn.name, where))
1156            raise QAPISemError(
1157                defn.info, "%s is already defined" % other_defn.describe())
1158        self._entity_dict[defn.name] = defn
1159
1160    def lookup_entity(self,name: str) -> Optional[QAPISchemaEntity]:
1161        return self._entity_dict.get(name)
1162
1163    def lookup_type(self, name: str) -> Optional[QAPISchemaType]:
1164        typ = self.lookup_entity(name)
1165        if isinstance(typ, QAPISchemaType):
1166            return typ
1167        return None
1168
1169    def resolve_type(
1170        self,
1171        name: str,
1172        info: Optional[QAPISourceInfo],
1173        what: Union[None, str, Callable[[QAPISourceInfo], str]],
1174    ) -> QAPISchemaType:
1175        typ = self.lookup_type(name)
1176        if not typ:
1177            assert info and what  # built-in types must not fail lookup
1178            if callable(what):
1179                what = what(info)
1180            raise QAPISemError(
1181                info, "%s uses unknown type '%s'" % (what, name))
1182        return typ
1183
1184    def _module_name(self, fname: str) -> str:
1185        if QAPISchemaModule.is_system_module(fname):
1186            return fname
1187        return os.path.relpath(fname, self._schema_dir)
1188
1189    def _make_module(self, fname: str) -> QAPISchemaModule:
1190        name = self._module_name(fname)
1191        if name not in self._module_dict:
1192            self._module_dict[name] = QAPISchemaModule(name)
1193        return self._module_dict[name]
1194
1195    def module_by_fname(self, fname: str) -> QAPISchemaModule:
1196        name = self._module_name(fname)
1197        return self._module_dict[name]
1198
1199    def _def_include(self, expr: QAPIExpression) -> None:
1200        include = expr['include']
1201        assert expr.doc is None
1202        self._def_entity(
1203            QAPISchemaInclude(self._make_module(include), expr.info))
1204
1205    def _def_builtin_type(
1206        self, name: str, json_type: str, c_type: str
1207    ) -> None:
1208        self._def_definition(QAPISchemaBuiltinType(name, json_type, c_type))
1209        # Instantiating only the arrays that are actually used would
1210        # be nice, but we can't as long as their generated code
1211        # (qapi-builtin-types.[ch]) may be shared by some other
1212        # schema.
1213        self._make_array_type(name, None)
1214
1215    def _def_predefineds(self) -> None:
1216        for t in [('str',    'string',  'char' + POINTER_SUFFIX),
1217                  ('number', 'number',  'double'),
1218                  ('int',    'int',     'int64_t'),
1219                  ('int8',   'int',     'int8_t'),
1220                  ('int16',  'int',     'int16_t'),
1221                  ('int32',  'int',     'int32_t'),
1222                  ('int64',  'int',     'int64_t'),
1223                  ('uint8',  'int',     'uint8_t'),
1224                  ('uint16', 'int',     'uint16_t'),
1225                  ('uint32', 'int',     'uint32_t'),
1226                  ('uint64', 'int',     'uint64_t'),
1227                  ('size',   'int',     'uint64_t'),
1228                  ('bool',   'boolean', 'bool'),
1229                  ('any',    'value',   'QObject' + POINTER_SUFFIX),
1230                  ('null',   'null',    'QNull' + POINTER_SUFFIX)]:
1231            self._def_builtin_type(*t)
1232        self.the_empty_object_type = QAPISchemaObjectType(
1233            'q_empty', None, None, None, None, None, [], None)
1234        self._def_definition(self.the_empty_object_type)
1235
1236        qtypes = ['none', 'qnull', 'qnum', 'qstring', 'qdict', 'qlist',
1237                  'qbool']
1238        qtype_values = self._make_enum_members(
1239            [{'name': n} for n in qtypes], None)
1240
1241        self._def_definition(QAPISchemaEnumType(
1242            'QType', None, None, None, None, qtype_values, 'QTYPE'))
1243
1244    def _make_features(
1245        self,
1246        features: Optional[List[Dict[str, Any]]],
1247        info: Optional[QAPISourceInfo],
1248    ) -> List[QAPISchemaFeature]:
1249        if features is None:
1250            return []
1251        return [QAPISchemaFeature(f['name'], info,
1252                                  QAPISchemaIfCond(f.get('if')))
1253                for f in features]
1254
1255    def _make_enum_member(
1256        self,
1257        name: str,
1258        ifcond: Optional[Union[str, Dict[str, Any]]],
1259        features: Optional[List[Dict[str, Any]]],
1260        info: Optional[QAPISourceInfo],
1261    ) -> QAPISchemaEnumMember:
1262        return QAPISchemaEnumMember(name, info,
1263                                    QAPISchemaIfCond(ifcond),
1264                                    self._make_features(features, info))
1265
1266    def _make_enum_members(
1267        self, values: List[Dict[str, Any]], info: Optional[QAPISourceInfo]
1268    ) -> List[QAPISchemaEnumMember]:
1269        return [self._make_enum_member(v['name'], v.get('if'),
1270                                       v.get('features'), info)
1271                for v in values]
1272
1273    def _make_array_type(
1274        self, element_type: str, info: Optional[QAPISourceInfo]
1275    ) -> str:
1276        name = element_type + 'List'    # reserved by check_defn_name_str()
1277        if not self.lookup_type(name):
1278            self._def_definition(QAPISchemaArrayType(
1279                name, info, element_type))
1280        return name
1281
1282    def _make_implicit_object_type(
1283        self,
1284        name: str,
1285        info: QAPISourceInfo,
1286        ifcond: QAPISchemaIfCond,
1287        role: str,
1288        members: List[QAPISchemaObjectTypeMember],
1289    ) -> Optional[str]:
1290        if not members:
1291            return None
1292        # See also QAPISchemaObjectTypeMember.describe()
1293        name = 'q_obj_%s-%s' % (name, role)
1294        typ = self.lookup_entity(name)
1295        if typ:
1296            assert(isinstance(typ, QAPISchemaObjectType))
1297            # The implicit object type has multiple users.  This can
1298            # only be a duplicate definition, which will be flagged
1299            # later.
1300            pass
1301        else:
1302            self._def_definition(QAPISchemaObjectType(
1303                name, info, None, ifcond, None, None, members, None))
1304        return name
1305
1306    def _def_enum_type(self, expr: QAPIExpression) -> None:
1307        name = expr['enum']
1308        data = expr['data']
1309        prefix = expr.get('prefix')
1310        ifcond = QAPISchemaIfCond(expr.get('if'))
1311        info = expr.info
1312        features = self._make_features(expr.get('features'), info)
1313        self._def_definition(QAPISchemaEnumType(
1314            name, info, expr.doc, ifcond, features,
1315            self._make_enum_members(data, info), prefix))
1316
1317    def _make_member(
1318        self,
1319        name: str,
1320        typ: Union[List[str], str],
1321        ifcond: QAPISchemaIfCond,
1322        features: Optional[List[Dict[str, Any]]],
1323        info: QAPISourceInfo,
1324    ) -> QAPISchemaObjectTypeMember:
1325        optional = False
1326        if name.startswith('*'):
1327            name = name[1:]
1328            optional = True
1329        if isinstance(typ, list):
1330            assert len(typ) == 1
1331            typ = self._make_array_type(typ[0], info)
1332        return QAPISchemaObjectTypeMember(name, info, typ, optional, ifcond,
1333                                          self._make_features(features, info))
1334
1335    def _make_members(
1336        self,
1337        data: Dict[str, Any],
1338        info: QAPISourceInfo,
1339    ) -> List[QAPISchemaObjectTypeMember]:
1340        return [self._make_member(key, value['type'],
1341                                  QAPISchemaIfCond(value.get('if')),
1342                                  value.get('features'), info)
1343                for (key, value) in data.items()]
1344
1345    def _def_struct_type(self, expr: QAPIExpression) -> None:
1346        name = expr['struct']
1347        base = expr.get('base')
1348        data = expr['data']
1349        info = expr.info
1350        ifcond = QAPISchemaIfCond(expr.get('if'))
1351        features = self._make_features(expr.get('features'), info)
1352        self._def_definition(QAPISchemaObjectType(
1353            name, info, expr.doc, ifcond, features, base,
1354            self._make_members(data, info),
1355            None))
1356
1357    def _make_variant(
1358        self,
1359        case: str,
1360        typ: str,
1361        ifcond: QAPISchemaIfCond,
1362        info: QAPISourceInfo,
1363    ) -> QAPISchemaVariant:
1364        if isinstance(typ, list):
1365            assert len(typ) == 1
1366            typ = self._make_array_type(typ[0], info)
1367        return QAPISchemaVariant(case, info, typ, ifcond)
1368
1369    def _def_union_type(self, expr: QAPIExpression) -> None:
1370        name = expr['union']
1371        base = expr['base']
1372        tag_name = expr['discriminator']
1373        data = expr['data']
1374        assert isinstance(data, dict)
1375        info = expr.info
1376        ifcond = QAPISchemaIfCond(expr.get('if'))
1377        features = self._make_features(expr.get('features'), info)
1378        if isinstance(base, dict):
1379            base = self._make_implicit_object_type(
1380                name, info, ifcond,
1381                'base', self._make_members(base, info))
1382        variants = [
1383            self._make_variant(key, value['type'],
1384                               QAPISchemaIfCond(value.get('if')),
1385                               info)
1386            for (key, value) in data.items()]
1387        members: List[QAPISchemaObjectTypeMember] = []
1388        self._def_definition(
1389            QAPISchemaObjectType(name, info, expr.doc, ifcond, features,
1390                                 base, members,
1391                                 QAPISchemaVariants(
1392                                     tag_name, info, None, variants)))
1393
1394    def _def_alternate_type(self, expr: QAPIExpression) -> None:
1395        name = expr['alternate']
1396        data = expr['data']
1397        assert isinstance(data, dict)
1398        ifcond = QAPISchemaIfCond(expr.get('if'))
1399        info = expr.info
1400        features = self._make_features(expr.get('features'), info)
1401        variants = [
1402            self._make_variant(key, value['type'],
1403                               QAPISchemaIfCond(value.get('if')),
1404                               info)
1405            for (key, value) in data.items()]
1406        tag_member = QAPISchemaObjectTypeMember('type', info, 'QType', False)
1407        self._def_definition(
1408            QAPISchemaAlternateType(
1409                name, info, expr.doc, ifcond, features,
1410                QAPISchemaVariants(None, info, tag_member, variants)))
1411
1412    def _def_command(self, expr: QAPIExpression) -> None:
1413        name = expr['command']
1414        data = expr.get('data')
1415        rets = expr.get('returns')
1416        gen = expr.get('gen', True)
1417        success_response = expr.get('success-response', True)
1418        boxed = expr.get('boxed', False)
1419        allow_oob = expr.get('allow-oob', False)
1420        allow_preconfig = expr.get('allow-preconfig', False)
1421        coroutine = expr.get('coroutine', False)
1422        ifcond = QAPISchemaIfCond(expr.get('if'))
1423        info = expr.info
1424        features = self._make_features(expr.get('features'), info)
1425        if isinstance(data, OrderedDict):
1426            data = self._make_implicit_object_type(
1427                name, info, ifcond,
1428                'arg', self._make_members(data, info))
1429        if isinstance(rets, list):
1430            assert len(rets) == 1
1431            rets = self._make_array_type(rets[0], info)
1432        self._def_definition(
1433            QAPISchemaCommand(name, info, expr.doc, ifcond, features, data,
1434                              rets, gen, success_response, boxed, allow_oob,
1435                              allow_preconfig, coroutine))
1436
1437    def _def_event(self, expr: QAPIExpression) -> None:
1438        name = expr['event']
1439        data = expr.get('data')
1440        boxed = expr.get('boxed', False)
1441        ifcond = QAPISchemaIfCond(expr.get('if'))
1442        info = expr.info
1443        features = self._make_features(expr.get('features'), info)
1444        if isinstance(data, OrderedDict):
1445            data = self._make_implicit_object_type(
1446                name, info, ifcond,
1447                'arg', self._make_members(data, info))
1448        self._def_definition(QAPISchemaEvent(name, info, expr.doc, ifcond,
1449                                             features, data, boxed))
1450
1451    def _def_exprs(self, exprs: List[QAPIExpression]) -> None:
1452        for expr in exprs:
1453            if 'enum' in expr:
1454                self._def_enum_type(expr)
1455            elif 'struct' in expr:
1456                self._def_struct_type(expr)
1457            elif 'union' in expr:
1458                self._def_union_type(expr)
1459            elif 'alternate' in expr:
1460                self._def_alternate_type(expr)
1461            elif 'command' in expr:
1462                self._def_command(expr)
1463            elif 'event' in expr:
1464                self._def_event(expr)
1465            elif 'include' in expr:
1466                self._def_include(expr)
1467            else:
1468                assert False
1469
1470    def check(self) -> None:
1471        for ent in self._entity_list:
1472            ent.check(self)
1473            ent.connect_doc()
1474        for ent in self._entity_list:
1475            ent.set_module(self)
1476        for doc in self.docs:
1477            doc.check()
1478
1479    def visit(self, visitor: QAPISchemaVisitor) -> None:
1480        visitor.visit_begin(self)
1481        for mod in self._module_dict.values():
1482            mod.visit(visitor)
1483        visitor.visit_end()
1484