xref: /openbmc/qemu/scripts/qapi/schema.py (revision 4abc8923)
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        branches: Optional[QAPISchemaBranches],
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        branches: Optional[QAPISchemaBranches],
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        alternatives: QAPISchemaAlternatives,
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        branches: Optional[QAPISchemaBranches],
528    ):
529        # struct has local_members, optional base, and no branches
530        # union has base, branches, and no local_members
531        super().__init__(name, info, doc, ifcond, features)
532        self.meta = 'union' if branches else 'struct'
533        for m in local_members:
534            m.set_defined_in(name)
535        if branches is not None:
536            branches.set_defined_in(name)
537        self._base_name = base
538        self.base = None
539        self.local_members = local_members
540        self.branches = branches
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.branches):
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.branches:
581            self.branches.check(schema, seen)
582            self.branches.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.branches:
599            self.branches.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.branches
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.branches)
639        visitor.visit_object_type_flat(
640            self.name, self.info, self.ifcond, self.features,
641            self.members, self.branches)
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        alternatives: QAPISchemaAlternatives,
655    ):
656        super().__init__(name, info, doc, ifcond, features)
657        assert alternatives.tag_member
658        alternatives.set_defined_in(name)
659        alternatives.tag_member.set_defined_in(self.name)
660        self.alternatives = alternatives
661
662    def check(self, schema: QAPISchema) -> None:
663        super().check(schema)
664        self.alternatives.tag_member.check(schema)
665        # Not calling self.alternatives.check_clash(), because there's
666        # nothing to clash with
667        self.alternatives.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.alternatives.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.alternatives.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,
716            self.alternatives)
717
718
719class QAPISchemaVariants:
720    def __init__(
721        self,
722        info: QAPISourceInfo,
723        variants: List[QAPISchemaVariant],
724    ):
725        self.info = info
726        self.tag_member: QAPISchemaObjectTypeMember
727        self.variants = variants
728
729    def set_defined_in(self, name: str) -> None:
730        for v in self.variants:
731            v.set_defined_in(name)
732
733    def check(
734            self, schema: QAPISchema, seen: Dict[str, QAPISchemaMember]
735    ) -> None:
736        for v in self.variants:
737            v.check(schema)
738
739
740class QAPISchemaBranches(QAPISchemaVariants):
741    def __init__(self,
742                 info: QAPISourceInfo,
743                 variants: List[QAPISchemaVariant],
744                 tag_name: str):
745        super().__init__(info, variants)
746        self._tag_name = tag_name
747
748    def check(
749            self, schema: QAPISchema, seen: Dict[str, QAPISchemaMember]
750    ) -> None:
751        # We need to narrow the member type:
752        tag_member = seen.get(c_name(self._tag_name))
753        assert (tag_member is None
754                or isinstance(tag_member, QAPISchemaObjectTypeMember))
755
756        base = "'base'"
757        # Pointing to the base type when not implicit would be
758        # nice, but we don't know it here
759        if not tag_member or self._tag_name != tag_member.name:
760            raise QAPISemError(
761                self.info,
762                "discriminator '%s' is not a member of %s"
763                % (self._tag_name, base))
764        self.tag_member = tag_member
765        # Here we do:
766        assert tag_member.defined_in
767        base_type = schema.lookup_type(tag_member.defined_in)
768        assert base_type
769        if not base_type.is_implicit():
770            base = "base type '%s'" % tag_member.defined_in
771        if not isinstance(tag_member.type, QAPISchemaEnumType):
772            raise QAPISemError(
773                self.info,
774                "discriminator member '%s' of %s must be of enum type"
775                % (self._tag_name, base))
776        if tag_member.optional:
777            raise QAPISemError(
778                self.info,
779                "discriminator member '%s' of %s must not be optional"
780                % (self._tag_name, base))
781        if tag_member.ifcond.is_present():
782            raise QAPISemError(
783                self.info,
784                "discriminator member '%s' of %s must not be conditional"
785                % (self._tag_name, base))
786        # branches that are not explicitly covered get an empty type
787        assert tag_member.defined_in
788        cases = {v.name for v in self.variants}
789        for m in tag_member.type.members:
790            if m.name not in cases:
791                v = QAPISchemaVariant(m.name, self.info,
792                                      'q_empty', m.ifcond)
793                v.set_defined_in(tag_member.defined_in)
794                self.variants.append(v)
795        if not self.variants:
796            raise QAPISemError(self.info, "union has no branches")
797        for v in self.variants:
798            v.check(schema)
799            # Union names must match enum values; alternate names are
800            # checked separately. Use 'seen' to tell the two apart.
801            if seen:
802                if v.name not in tag_member.type.member_names():
803                    raise QAPISemError(
804                        self.info,
805                        "branch '%s' is not a value of %s"
806                        % (v.name, tag_member.type.describe()))
807                if not isinstance(v.type, QAPISchemaObjectType):
808                    raise QAPISemError(
809                        self.info,
810                        "%s cannot use %s"
811                        % (v.describe(self.info), v.type.describe()))
812                v.type.check(schema)
813
814    def check_clash(
815        self,
816        info: Optional[QAPISourceInfo],
817        seen: Dict[str, QAPISchemaMember],
818    ) -> None:
819        for v in self.variants:
820            # Reset seen map for each variant, since qapi names from one
821            # branch do not affect another branch.
822            #
823            # v.type's typing is enforced in check() above.
824            assert isinstance(v.type, QAPISchemaObjectType)
825            v.type.check_clash(info, dict(seen))
826
827
828class QAPISchemaAlternatives(QAPISchemaVariants):
829    def __init__(self,
830                 info: QAPISourceInfo,
831                 variants: List[QAPISchemaVariant],
832                 tag_member: QAPISchemaObjectTypeMember):
833        super().__init__(info, variants)
834        self.tag_member = tag_member
835
836    def check(
837            self, schema: QAPISchema, seen: Dict[str, QAPISchemaMember]
838    ) -> None:
839        super().check(schema, seen)
840        assert isinstance(self.tag_member.type, QAPISchemaEnumType)
841        assert not self.tag_member.optional
842        assert not self.tag_member.ifcond.is_present()
843
844
845class QAPISchemaMember:
846    """ Represents object members, enum members and features """
847    role = 'member'
848
849    def __init__(
850        self,
851        name: str,
852        info: Optional[QAPISourceInfo],
853        ifcond: Optional[QAPISchemaIfCond] = None,
854    ):
855        self.name = name
856        self.info = info
857        self.ifcond = ifcond or QAPISchemaIfCond()
858        self.defined_in: Optional[str] = None
859
860    def set_defined_in(self, name: str) -> None:
861        assert not self.defined_in
862        self.defined_in = name
863
864    def check_clash(
865        self,
866        info: Optional[QAPISourceInfo],
867        seen: Dict[str, QAPISchemaMember],
868    ) -> None:
869        cname = c_name(self.name)
870        if cname in seen:
871            raise QAPISemError(
872                info,
873                "%s collides with %s"
874                % (self.describe(info), seen[cname].describe(info)))
875        seen[cname] = self
876
877    def connect_doc(self, doc: Optional[QAPIDoc]) -> None:
878        if doc:
879            doc.connect_member(self)
880
881    def describe(self, info: Optional[QAPISourceInfo]) -> str:
882        role = self.role
883        meta = 'type'
884        defined_in = self.defined_in
885        assert defined_in
886
887        if defined_in.startswith('q_obj_'):
888            # See QAPISchema._make_implicit_object_type() - reverse the
889            # mapping there to create a nice human-readable description
890            defined_in = defined_in[6:]
891            if defined_in.endswith('-arg'):
892                # Implicit type created for a command's dict 'data'
893                assert role == 'member'
894                role = 'parameter'
895                meta = 'command'
896                defined_in = defined_in[:-4]
897            elif defined_in.endswith('-base'):
898                # Implicit type created for a union's dict 'base'
899                role = 'base ' + role
900                defined_in = defined_in[:-5]
901            else:
902                assert False
903
904        assert info is not None
905        if defined_in != info.defn_name:
906            return "%s '%s' of %s '%s'" % (role, self.name, meta, defined_in)
907        return "%s '%s'" % (role, self.name)
908
909
910class QAPISchemaEnumMember(QAPISchemaMember):
911    role = 'value'
912
913    def __init__(
914        self,
915        name: str,
916        info: Optional[QAPISourceInfo],
917        ifcond: Optional[QAPISchemaIfCond] = None,
918        features: Optional[List[QAPISchemaFeature]] = None,
919    ):
920        super().__init__(name, info, ifcond)
921        for f in features or []:
922            f.set_defined_in(name)
923        self.features = features or []
924
925    def connect_doc(self, doc: Optional[QAPIDoc]) -> None:
926        super().connect_doc(doc)
927        if doc:
928            for f in self.features:
929                doc.connect_feature(f)
930
931
932class QAPISchemaFeature(QAPISchemaMember):
933    role = 'feature'
934
935    def is_special(self) -> bool:
936        return self.name in ('deprecated', 'unstable')
937
938
939class QAPISchemaObjectTypeMember(QAPISchemaMember):
940    def __init__(
941        self,
942        name: str,
943        info: QAPISourceInfo,
944        typ: str,
945        optional: bool,
946        ifcond: Optional[QAPISchemaIfCond] = None,
947        features: Optional[List[QAPISchemaFeature]] = None,
948    ):
949        super().__init__(name, info, ifcond)
950        for f in features or []:
951            f.set_defined_in(name)
952        self._type_name = typ
953        self.type: QAPISchemaType  # set during check()
954        self.optional = optional
955        self.features = features or []
956
957    def need_has(self) -> bool:
958        return self.optional and self.type.need_has_if_optional()
959
960    def check(self, schema: QAPISchema) -> None:
961        assert self.defined_in
962        self.type = schema.resolve_type(self._type_name, self.info,
963                                        self.describe)
964        seen: Dict[str, QAPISchemaMember] = {}
965        for f in self.features:
966            f.check_clash(self.info, seen)
967
968    def connect_doc(self, doc: Optional[QAPIDoc]) -> None:
969        super().connect_doc(doc)
970        if doc:
971            for f in self.features:
972                doc.connect_feature(f)
973
974
975class QAPISchemaVariant(QAPISchemaObjectTypeMember):
976    role = 'branch'
977
978    def __init__(
979        self,
980        name: str,
981        info: QAPISourceInfo,
982        typ: str,
983        ifcond: QAPISchemaIfCond,
984    ):
985        super().__init__(name, info, typ, False, ifcond)
986
987
988class QAPISchemaCommand(QAPISchemaDefinition):
989    meta = 'command'
990
991    def __init__(
992        self,
993        name: str,
994        info: QAPISourceInfo,
995        doc: Optional[QAPIDoc],
996        ifcond: QAPISchemaIfCond,
997        features: List[QAPISchemaFeature],
998        arg_type: Optional[str],
999        ret_type: Optional[str],
1000        gen: bool,
1001        success_response: bool,
1002        boxed: bool,
1003        allow_oob: bool,
1004        allow_preconfig: bool,
1005        coroutine: bool,
1006    ):
1007        super().__init__(name, info, doc, ifcond, features)
1008        self._arg_type_name = arg_type
1009        self.arg_type: Optional[QAPISchemaObjectType] = None
1010        self._ret_type_name = ret_type
1011        self.ret_type: Optional[QAPISchemaType] = None
1012        self.gen = gen
1013        self.success_response = success_response
1014        self.boxed = boxed
1015        self.allow_oob = allow_oob
1016        self.allow_preconfig = allow_preconfig
1017        self.coroutine = coroutine
1018
1019    def check(self, schema: QAPISchema) -> None:
1020        assert self.info is not None
1021        super().check(schema)
1022        if self._arg_type_name:
1023            arg_type = schema.resolve_type(
1024                self._arg_type_name, self.info, "command's 'data'")
1025            if not isinstance(arg_type, QAPISchemaObjectType):
1026                raise QAPISemError(
1027                    self.info,
1028                    "command's 'data' cannot take %s"
1029                    % arg_type.describe())
1030            self.arg_type = arg_type
1031            if self.arg_type.branches and not self.boxed:
1032                raise QAPISemError(
1033                    self.info,
1034                    "command's 'data' can take %s only with 'boxed': true"
1035                    % self.arg_type.describe())
1036            self.arg_type.check(schema)
1037            if self.arg_type.has_conditional_members() and not self.boxed:
1038                raise QAPISemError(
1039                    self.info,
1040                    "conditional command arguments require 'boxed': true")
1041        if self._ret_type_name:
1042            self.ret_type = schema.resolve_type(
1043                self._ret_type_name, self.info, "command's 'returns'")
1044            if self.name not in self.info.pragma.command_returns_exceptions:
1045                typ = self.ret_type
1046                if isinstance(typ, QAPISchemaArrayType):
1047                    typ = typ.element_type
1048                if not isinstance(typ, QAPISchemaObjectType):
1049                    raise QAPISemError(
1050                        self.info,
1051                        "command's 'returns' cannot take %s"
1052                        % self.ret_type.describe())
1053
1054    def connect_doc(self, doc: Optional[QAPIDoc] = None) -> None:
1055        super().connect_doc(doc)
1056        doc = doc or self.doc
1057        if doc:
1058            if self.arg_type and self.arg_type.is_implicit():
1059                self.arg_type.connect_doc(doc)
1060
1061    def visit(self, visitor: QAPISchemaVisitor) -> None:
1062        super().visit(visitor)
1063        visitor.visit_command(
1064            self.name, self.info, self.ifcond, self.features,
1065            self.arg_type, self.ret_type, self.gen, self.success_response,
1066            self.boxed, self.allow_oob, self.allow_preconfig,
1067            self.coroutine)
1068
1069
1070class QAPISchemaEvent(QAPISchemaDefinition):
1071    meta = 'event'
1072
1073    def __init__(
1074        self,
1075        name: str,
1076        info: QAPISourceInfo,
1077        doc: Optional[QAPIDoc],
1078        ifcond: QAPISchemaIfCond,
1079        features: List[QAPISchemaFeature],
1080        arg_type: Optional[str],
1081        boxed: bool,
1082    ):
1083        super().__init__(name, info, doc, ifcond, features)
1084        self._arg_type_name = arg_type
1085        self.arg_type: Optional[QAPISchemaObjectType] = None
1086        self.boxed = boxed
1087
1088    def check(self, schema: QAPISchema) -> None:
1089        super().check(schema)
1090        if self._arg_type_name:
1091            typ = schema.resolve_type(
1092                self._arg_type_name, self.info, "event's 'data'")
1093            if not isinstance(typ, QAPISchemaObjectType):
1094                raise QAPISemError(
1095                    self.info,
1096                    "event's 'data' cannot take %s"
1097                    % typ.describe())
1098            self.arg_type = typ
1099            if self.arg_type.branches and not self.boxed:
1100                raise QAPISemError(
1101                    self.info,
1102                    "event's 'data' can take %s only with 'boxed': true"
1103                    % self.arg_type.describe())
1104            self.arg_type.check(schema)
1105            if self.arg_type.has_conditional_members() and not self.boxed:
1106                raise QAPISemError(
1107                    self.info,
1108                    "conditional event arguments require 'boxed': true")
1109
1110    def connect_doc(self, doc: Optional[QAPIDoc] = None) -> None:
1111        super().connect_doc(doc)
1112        doc = doc or self.doc
1113        if doc:
1114            if self.arg_type and self.arg_type.is_implicit():
1115                self.arg_type.connect_doc(doc)
1116
1117    def visit(self, visitor: QAPISchemaVisitor) -> None:
1118        super().visit(visitor)
1119        visitor.visit_event(
1120            self.name, self.info, self.ifcond, self.features,
1121            self.arg_type, self.boxed)
1122
1123
1124class QAPISchema:
1125    def __init__(self, fname: str):
1126        self.fname = fname
1127
1128        try:
1129            parser = QAPISchemaParser(fname)
1130        except OSError as err:
1131            raise QAPIError(
1132                f"can't read schema file '{fname}': {err.strerror}"
1133            ) from err
1134
1135        exprs = check_exprs(parser.exprs)
1136        self.docs = parser.docs
1137        self._entity_list: List[QAPISchemaEntity] = []
1138        self._entity_dict: Dict[str, QAPISchemaDefinition] = {}
1139        self._module_dict: Dict[str, QAPISchemaModule] = OrderedDict()
1140        self._schema_dir = os.path.dirname(fname)
1141        self._make_module(QAPISchemaModule.BUILTIN_MODULE_NAME)
1142        self._make_module(fname)
1143        self._predefining = True
1144        self._def_predefineds()
1145        self._predefining = False
1146        self._def_exprs(exprs)
1147        self.check()
1148
1149    def _def_entity(self, ent: QAPISchemaEntity) -> None:
1150        self._entity_list.append(ent)
1151
1152    def _def_definition(self, defn: QAPISchemaDefinition) -> None:
1153        # Only the predefined types are allowed to not have info
1154        assert defn.info or self._predefining
1155        self._def_entity(defn)
1156        # TODO reject names that differ only in '_' vs. '.'  vs. '-',
1157        # because they're liable to clash in generated C.
1158        other_defn = self._entity_dict.get(defn.name)
1159        if other_defn:
1160            if other_defn.info:
1161                where = QAPISourceError(other_defn.info, "previous definition")
1162                raise QAPISemError(
1163                    defn.info,
1164                    "'%s' is already defined\n%s" % (defn.name, where))
1165            raise QAPISemError(
1166                defn.info, "%s is already defined" % other_defn.describe())
1167        self._entity_dict[defn.name] = defn
1168
1169    def lookup_entity(self,name: str) -> Optional[QAPISchemaEntity]:
1170        return self._entity_dict.get(name)
1171
1172    def lookup_type(self, name: str) -> Optional[QAPISchemaType]:
1173        typ = self.lookup_entity(name)
1174        if isinstance(typ, QAPISchemaType):
1175            return typ
1176        return None
1177
1178    def resolve_type(
1179        self,
1180        name: str,
1181        info: Optional[QAPISourceInfo],
1182        what: Union[None, str, Callable[[QAPISourceInfo], str]],
1183    ) -> QAPISchemaType:
1184        typ = self.lookup_type(name)
1185        if not typ:
1186            assert info and what  # built-in types must not fail lookup
1187            if callable(what):
1188                what = what(info)
1189            raise QAPISemError(
1190                info, "%s uses unknown type '%s'" % (what, name))
1191        return typ
1192
1193    def _module_name(self, fname: str) -> str:
1194        if QAPISchemaModule.is_system_module(fname):
1195            return fname
1196        return os.path.relpath(fname, self._schema_dir)
1197
1198    def _make_module(self, fname: str) -> QAPISchemaModule:
1199        name = self._module_name(fname)
1200        if name not in self._module_dict:
1201            self._module_dict[name] = QAPISchemaModule(name)
1202        return self._module_dict[name]
1203
1204    def module_by_fname(self, fname: str) -> QAPISchemaModule:
1205        name = self._module_name(fname)
1206        return self._module_dict[name]
1207
1208    def _def_include(self, expr: QAPIExpression) -> None:
1209        include = expr['include']
1210        assert expr.doc is None
1211        self._def_entity(
1212            QAPISchemaInclude(self._make_module(include), expr.info))
1213
1214    def _def_builtin_type(
1215        self, name: str, json_type: str, c_type: str
1216    ) -> None:
1217        self._def_definition(QAPISchemaBuiltinType(name, json_type, c_type))
1218        # Instantiating only the arrays that are actually used would
1219        # be nice, but we can't as long as their generated code
1220        # (qapi-builtin-types.[ch]) may be shared by some other
1221        # schema.
1222        self._make_array_type(name, None)
1223
1224    def _def_predefineds(self) -> None:
1225        for t in [('str',    'string',  'char' + POINTER_SUFFIX),
1226                  ('number', 'number',  'double'),
1227                  ('int',    'int',     'int64_t'),
1228                  ('int8',   'int',     'int8_t'),
1229                  ('int16',  'int',     'int16_t'),
1230                  ('int32',  'int',     'int32_t'),
1231                  ('int64',  'int',     'int64_t'),
1232                  ('uint8',  'int',     'uint8_t'),
1233                  ('uint16', 'int',     'uint16_t'),
1234                  ('uint32', 'int',     'uint32_t'),
1235                  ('uint64', 'int',     'uint64_t'),
1236                  ('size',   'int',     'uint64_t'),
1237                  ('bool',   'boolean', 'bool'),
1238                  ('any',    'value',   'QObject' + POINTER_SUFFIX),
1239                  ('null',   'null',    'QNull' + POINTER_SUFFIX)]:
1240            self._def_builtin_type(*t)
1241        self.the_empty_object_type = QAPISchemaObjectType(
1242            'q_empty', None, None, None, None, None, [], None)
1243        self._def_definition(self.the_empty_object_type)
1244
1245        qtypes = ['none', 'qnull', 'qnum', 'qstring', 'qdict', 'qlist',
1246                  'qbool']
1247        qtype_values = self._make_enum_members(
1248            [{'name': n} for n in qtypes], None)
1249
1250        self._def_definition(QAPISchemaEnumType(
1251            'QType', None, None, None, None, qtype_values, 'QTYPE'))
1252
1253    def _make_features(
1254        self,
1255        features: Optional[List[Dict[str, Any]]],
1256        info: Optional[QAPISourceInfo],
1257    ) -> List[QAPISchemaFeature]:
1258        if features is None:
1259            return []
1260        return [QAPISchemaFeature(f['name'], info,
1261                                  QAPISchemaIfCond(f.get('if')))
1262                for f in features]
1263
1264    def _make_enum_member(
1265        self,
1266        name: str,
1267        ifcond: Optional[Union[str, Dict[str, Any]]],
1268        features: Optional[List[Dict[str, Any]]],
1269        info: Optional[QAPISourceInfo],
1270    ) -> QAPISchemaEnumMember:
1271        return QAPISchemaEnumMember(name, info,
1272                                    QAPISchemaIfCond(ifcond),
1273                                    self._make_features(features, info))
1274
1275    def _make_enum_members(
1276        self, values: List[Dict[str, Any]], info: Optional[QAPISourceInfo]
1277    ) -> List[QAPISchemaEnumMember]:
1278        return [self._make_enum_member(v['name'], v.get('if'),
1279                                       v.get('features'), info)
1280                for v in values]
1281
1282    def _make_array_type(
1283        self, element_type: str, info: Optional[QAPISourceInfo]
1284    ) -> str:
1285        name = element_type + 'List'    # reserved by check_defn_name_str()
1286        if not self.lookup_type(name):
1287            self._def_definition(QAPISchemaArrayType(
1288                name, info, element_type))
1289        return name
1290
1291    def _make_implicit_object_type(
1292        self,
1293        name: str,
1294        info: QAPISourceInfo,
1295        ifcond: QAPISchemaIfCond,
1296        role: str,
1297        members: List[QAPISchemaObjectTypeMember],
1298    ) -> Optional[str]:
1299        if not members:
1300            return None
1301        # See also QAPISchemaObjectTypeMember.describe()
1302        name = 'q_obj_%s-%s' % (name, role)
1303        typ = self.lookup_entity(name)
1304        if typ:
1305            assert(isinstance(typ, QAPISchemaObjectType))
1306            # The implicit object type has multiple users.  This can
1307            # only be a duplicate definition, which will be flagged
1308            # later.
1309            pass
1310        else:
1311            self._def_definition(QAPISchemaObjectType(
1312                name, info, None, ifcond, None, None, members, None))
1313        return name
1314
1315    def _def_enum_type(self, expr: QAPIExpression) -> None:
1316        name = expr['enum']
1317        data = expr['data']
1318        prefix = expr.get('prefix')
1319        ifcond = QAPISchemaIfCond(expr.get('if'))
1320        info = expr.info
1321        features = self._make_features(expr.get('features'), info)
1322        self._def_definition(QAPISchemaEnumType(
1323            name, info, expr.doc, ifcond, features,
1324            self._make_enum_members(data, info), prefix))
1325
1326    def _make_member(
1327        self,
1328        name: str,
1329        typ: Union[List[str], str],
1330        ifcond: QAPISchemaIfCond,
1331        features: Optional[List[Dict[str, Any]]],
1332        info: QAPISourceInfo,
1333    ) -> QAPISchemaObjectTypeMember:
1334        optional = False
1335        if name.startswith('*'):
1336            name = name[1:]
1337            optional = True
1338        if isinstance(typ, list):
1339            assert len(typ) == 1
1340            typ = self._make_array_type(typ[0], info)
1341        return QAPISchemaObjectTypeMember(name, info, typ, optional, ifcond,
1342                                          self._make_features(features, info))
1343
1344    def _make_members(
1345        self,
1346        data: Dict[str, Any],
1347        info: QAPISourceInfo,
1348    ) -> List[QAPISchemaObjectTypeMember]:
1349        return [self._make_member(key, value['type'],
1350                                  QAPISchemaIfCond(value.get('if')),
1351                                  value.get('features'), info)
1352                for (key, value) in data.items()]
1353
1354    def _def_struct_type(self, expr: QAPIExpression) -> None:
1355        name = expr['struct']
1356        base = expr.get('base')
1357        data = expr['data']
1358        info = expr.info
1359        ifcond = QAPISchemaIfCond(expr.get('if'))
1360        features = self._make_features(expr.get('features'), info)
1361        self._def_definition(QAPISchemaObjectType(
1362            name, info, expr.doc, ifcond, features, base,
1363            self._make_members(data, info),
1364            None))
1365
1366    def _make_variant(
1367        self,
1368        case: str,
1369        typ: str,
1370        ifcond: QAPISchemaIfCond,
1371        info: QAPISourceInfo,
1372    ) -> QAPISchemaVariant:
1373        if isinstance(typ, list):
1374            assert len(typ) == 1
1375            typ = self._make_array_type(typ[0], info)
1376        return QAPISchemaVariant(case, info, typ, ifcond)
1377
1378    def _def_union_type(self, expr: QAPIExpression) -> None:
1379        name = expr['union']
1380        base = expr['base']
1381        tag_name = expr['discriminator']
1382        data = expr['data']
1383        assert isinstance(data, dict)
1384        info = expr.info
1385        ifcond = QAPISchemaIfCond(expr.get('if'))
1386        features = self._make_features(expr.get('features'), info)
1387        if isinstance(base, dict):
1388            base = self._make_implicit_object_type(
1389                name, info, ifcond,
1390                'base', self._make_members(base, info))
1391        variants = [
1392            self._make_variant(key, value['type'],
1393                               QAPISchemaIfCond(value.get('if')),
1394                               info)
1395            for (key, value) in data.items()]
1396        members: List[QAPISchemaObjectTypeMember] = []
1397        self._def_definition(
1398            QAPISchemaObjectType(name, info, expr.doc, ifcond, features,
1399                                 base, members,
1400                                 QAPISchemaBranches(
1401                                     info, variants, tag_name)))
1402
1403    def _def_alternate_type(self, expr: QAPIExpression) -> None:
1404        name = expr['alternate']
1405        data = expr['data']
1406        assert isinstance(data, dict)
1407        ifcond = QAPISchemaIfCond(expr.get('if'))
1408        info = expr.info
1409        features = self._make_features(expr.get('features'), info)
1410        variants = [
1411            self._make_variant(key, value['type'],
1412                               QAPISchemaIfCond(value.get('if')),
1413                               info)
1414            for (key, value) in data.items()]
1415        tag_member = QAPISchemaObjectTypeMember('type', info, 'QType', False)
1416        self._def_definition(
1417            QAPISchemaAlternateType(
1418                name, info, expr.doc, ifcond, features,
1419                QAPISchemaAlternatives(info, variants, tag_member)))
1420
1421    def _def_command(self, expr: QAPIExpression) -> None:
1422        name = expr['command']
1423        data = expr.get('data')
1424        rets = expr.get('returns')
1425        gen = expr.get('gen', True)
1426        success_response = expr.get('success-response', True)
1427        boxed = expr.get('boxed', False)
1428        allow_oob = expr.get('allow-oob', False)
1429        allow_preconfig = expr.get('allow-preconfig', False)
1430        coroutine = expr.get('coroutine', False)
1431        ifcond = QAPISchemaIfCond(expr.get('if'))
1432        info = expr.info
1433        features = self._make_features(expr.get('features'), info)
1434        if isinstance(data, OrderedDict):
1435            data = self._make_implicit_object_type(
1436                name, info, ifcond,
1437                'arg', self._make_members(data, info))
1438        if isinstance(rets, list):
1439            assert len(rets) == 1
1440            rets = self._make_array_type(rets[0], info)
1441        self._def_definition(
1442            QAPISchemaCommand(name, info, expr.doc, ifcond, features, data,
1443                              rets, gen, success_response, boxed, allow_oob,
1444                              allow_preconfig, coroutine))
1445
1446    def _def_event(self, expr: QAPIExpression) -> None:
1447        name = expr['event']
1448        data = expr.get('data')
1449        boxed = expr.get('boxed', False)
1450        ifcond = QAPISchemaIfCond(expr.get('if'))
1451        info = expr.info
1452        features = self._make_features(expr.get('features'), info)
1453        if isinstance(data, OrderedDict):
1454            data = self._make_implicit_object_type(
1455                name, info, ifcond,
1456                'arg', self._make_members(data, info))
1457        self._def_definition(QAPISchemaEvent(name, info, expr.doc, ifcond,
1458                                             features, data, boxed))
1459
1460    def _def_exprs(self, exprs: List[QAPIExpression]) -> None:
1461        for expr in exprs:
1462            if 'enum' in expr:
1463                self._def_enum_type(expr)
1464            elif 'struct' in expr:
1465                self._def_struct_type(expr)
1466            elif 'union' in expr:
1467                self._def_union_type(expr)
1468            elif 'alternate' in expr:
1469                self._def_alternate_type(expr)
1470            elif 'command' in expr:
1471                self._def_command(expr)
1472            elif 'event' in expr:
1473                self._def_event(expr)
1474            elif 'include' in expr:
1475                self._def_include(expr)
1476            else:
1477                assert False
1478
1479    def check(self) -> None:
1480        for ent in self._entity_list:
1481            ent.check(self)
1482            ent.connect_doc()
1483        for ent in self._entity_list:
1484            ent.set_module(self)
1485        for doc in self.docs:
1486            doc.check()
1487
1488    def visit(self, visitor: QAPISchemaVisitor) -> None:
1489        visitor.visit_begin(self)
1490        for mod in self._module_dict.values():
1491            mod.visit(visitor)
1492        visitor.visit_end()
1493