scripts/qapi/schema.py

   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
  19 from __future__ import annotations
  20
  21 from abc import ABC, abstractmethod
  22 from collections import OrderedDict
  23 import os
  24 import re
  25 from typing import (
  26     Any,
  27     Callable,
  28     Dict,
  29     List,
  30     Optional,
  31     Union,
  32     cast,
  33 )
  34
  35 from .common import (
  36     POINTER_SUFFIX,
  37     c_name,
  38     cgen_ifcond,
  39     docgen_ifcond,
  40     gen_endif,
  41     gen_if,
  42 )
  43 from .error import QAPIError, QAPISemError, QAPISourceError
  44 from .expr import check_exprs
  45 from .parser import QAPIDoc, QAPIExpression, QAPISchemaParser
  46 from .source import QAPISourceInfo
  47
  48
  49 class 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
  72 class 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
 115 class 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
 167 class 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
 272 class 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
 317 class 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
 327 class 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
 380 class 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
 412 class 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
 463 class 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
 517 class 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
 644 class 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
 719 class 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
 740 class 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
 828 class 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
 845 class 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
 910 class 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
 932 class QAPISchemaFeature(QAPISchemaMember):
 933     role = 'feature'
 934
 935     def is_special(self) -> bool:
 936         return self.name in ('deprecated', 'unstable')
 937
 938
 939 class 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
 975 class 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
 988 class 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
1070 class 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
1124 class 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()