xref: /openbmc/qemu/scripts/qapi/schema.py (revision 4e116893)
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# TODO catching name collisions in generated code would be nice
16
17from collections import OrderedDict
18import os
19import re
20from typing import Optional
21
22from .common import (
23    POINTER_SUFFIX,
24    c_name,
25    cgen_ifcond,
26    docgen_ifcond,
27    gen_endif,
28    gen_if,
29)
30from .error import QAPIError, QAPISemError, QAPISourceError
31from .expr import check_exprs
32from .parser import QAPISchemaParser
33
34
35class QAPISchemaIfCond:
36    def __init__(self, ifcond=None):
37        self.ifcond = ifcond
38
39    def _cgen(self):
40        return cgen_ifcond(self.ifcond)
41
42    def gen_if(self):
43        return gen_if(self._cgen())
44
45    def gen_endif(self):
46        return gen_endif(self._cgen())
47
48    def docgen(self):
49        return docgen_ifcond(self.ifcond)
50
51    def is_present(self):
52        return bool(self.ifcond)
53
54
55class QAPISchemaEntity:
56    meta: Optional[str] = None
57
58    def __init__(self, name: str, info, doc, ifcond=None, features=None):
59        assert name is None or isinstance(name, str)
60        for f in features or []:
61            assert isinstance(f, QAPISchemaFeature)
62            f.set_defined_in(name)
63        self.name = name
64        self._module = None
65        # For explicitly defined entities, info points to the (explicit)
66        # definition.  For builtins (and their arrays), info is None.
67        # For implicitly defined entities, info points to a place that
68        # triggered the implicit definition (there may be more than one
69        # such place).
70        self.info = info
71        self.doc = doc
72        self._ifcond = ifcond or QAPISchemaIfCond()
73        self.features = features or []
74        self._checked = False
75
76    def c_name(self):
77        return c_name(self.name)
78
79    def check(self, schema):
80        assert not self._checked
81        seen = {}
82        for f in self.features:
83            f.check_clash(self.info, seen)
84        self._checked = True
85
86    def connect_doc(self, doc=None):
87        doc = doc or self.doc
88        if doc:
89            for f in self.features:
90                doc.connect_feature(f)
91
92    def check_doc(self):
93        if self.doc:
94            self.doc.check()
95
96    def _set_module(self, schema, info):
97        assert self._checked
98        fname = info.fname if info else QAPISchemaModule.BUILTIN_MODULE_NAME
99        self._module = schema.module_by_fname(fname)
100        self._module.add_entity(self)
101
102    def set_module(self, schema):
103        self._set_module(schema, self.info)
104
105    @property
106    def ifcond(self):
107        assert self._checked
108        return self._ifcond
109
110    def is_implicit(self):
111        return not self.info
112
113    def visit(self, visitor):
114        assert self._checked
115
116    def describe(self):
117        assert self.meta
118        return "%s '%s'" % (self.meta, self.name)
119
120
121class QAPISchemaVisitor:
122    def visit_begin(self, schema):
123        pass
124
125    def visit_end(self):
126        pass
127
128    def visit_module(self, name):
129        pass
130
131    def visit_needed(self, entity):
132        # Default to visiting everything
133        return True
134
135    def visit_include(self, name, info):
136        pass
137
138    def visit_builtin_type(self, name, info, json_type):
139        pass
140
141    def visit_enum_type(self, name, info, ifcond, features, members, prefix):
142        pass
143
144    def visit_array_type(self, name, info, ifcond, element_type):
145        pass
146
147    def visit_object_type(self, name, info, ifcond, features,
148                          base, members, variants):
149        pass
150
151    def visit_object_type_flat(self, name, info, ifcond, features,
152                               members, variants):
153        pass
154
155    def visit_alternate_type(self, name, info, ifcond, features, variants):
156        pass
157
158    def visit_command(self, name, info, ifcond, features,
159                      arg_type, ret_type, gen, success_response, boxed,
160                      allow_oob, allow_preconfig, coroutine):
161        pass
162
163    def visit_event(self, name, info, ifcond, features, arg_type, boxed):
164        pass
165
166
167class QAPISchemaModule:
168
169    BUILTIN_MODULE_NAME = './builtin'
170
171    def __init__(self, name):
172        self.name = name
173        self._entity_list = []
174
175    @staticmethod
176    def is_system_module(name: str) -> bool:
177        """
178        System modules are internally defined modules.
179
180        Their names start with the "./" prefix.
181        """
182        return name.startswith('./')
183
184    @classmethod
185    def is_user_module(cls, name: str) -> bool:
186        """
187        User modules are those defined by the user in qapi JSON files.
188
189        They do not start with the "./" prefix.
190        """
191        return not cls.is_system_module(name)
192
193    @classmethod
194    def is_builtin_module(cls, name: str) -> bool:
195        """
196        The built-in module is a single System module for the built-in types.
197
198        It is always "./builtin".
199        """
200        return name == cls.BUILTIN_MODULE_NAME
201
202    def add_entity(self, ent):
203        self._entity_list.append(ent)
204
205    def visit(self, visitor):
206        visitor.visit_module(self.name)
207        for entity in self._entity_list:
208            if visitor.visit_needed(entity):
209                entity.visit(visitor)
210
211
212class QAPISchemaInclude(QAPISchemaEntity):
213    def __init__(self, sub_module, info):
214        super().__init__(None, info, None)
215        self._sub_module = sub_module
216
217    def visit(self, visitor):
218        super().visit(visitor)
219        visitor.visit_include(self._sub_module.name, self.info)
220
221
222class QAPISchemaType(QAPISchemaEntity):
223    # Return the C type for common use.
224    # For the types we commonly box, this is a pointer type.
225    def c_type(self):
226        pass
227
228    # Return the C type to be used in a parameter list.
229    def c_param_type(self):
230        return self.c_type()
231
232    # Return the C type to be used where we suppress boxing.
233    def c_unboxed_type(self):
234        return self.c_type()
235
236    def json_type(self):
237        pass
238
239    def alternate_qtype(self):
240        json2qtype = {
241            'null':    'QTYPE_QNULL',
242            'string':  'QTYPE_QSTRING',
243            'number':  'QTYPE_QNUM',
244            'int':     'QTYPE_QNUM',
245            'boolean': 'QTYPE_QBOOL',
246            'object':  'QTYPE_QDICT'
247        }
248        return json2qtype.get(self.json_type())
249
250    def doc_type(self):
251        if self.is_implicit():
252            return None
253        return self.name
254
255    def check(self, schema):
256        QAPISchemaEntity.check(self, schema)
257        if 'deprecated' in [f.name for f in self.features]:
258            raise QAPISemError(
259                self.info, "feature 'deprecated' is not supported for types")
260
261    def describe(self):
262        assert self.meta
263        return "%s type '%s'" % (self.meta, self.name)
264
265
266class QAPISchemaBuiltinType(QAPISchemaType):
267    meta = 'built-in'
268
269    def __init__(self, name, json_type, c_type):
270        super().__init__(name, None, None)
271        assert not c_type or isinstance(c_type, str)
272        assert json_type in ('string', 'number', 'int', 'boolean', 'null',
273                             'value')
274        self._json_type_name = json_type
275        self._c_type_name = c_type
276
277    def c_name(self):
278        return self.name
279
280    def c_type(self):
281        return self._c_type_name
282
283    def c_param_type(self):
284        if self.name == 'str':
285            return 'const ' + self._c_type_name
286        return self._c_type_name
287
288    def json_type(self):
289        return self._json_type_name
290
291    def doc_type(self):
292        return self.json_type()
293
294    def visit(self, visitor):
295        super().visit(visitor)
296        visitor.visit_builtin_type(self.name, self.info, self.json_type())
297
298
299class QAPISchemaEnumType(QAPISchemaType):
300    meta = 'enum'
301
302    def __init__(self, name, info, doc, ifcond, features, members, prefix):
303        super().__init__(name, info, doc, ifcond, features)
304        for m in members:
305            assert isinstance(m, QAPISchemaEnumMember)
306            m.set_defined_in(name)
307        assert prefix is None or isinstance(prefix, str)
308        self.members = members
309        self.prefix = prefix
310
311    def check(self, schema):
312        super().check(schema)
313        seen = {}
314        for m in self.members:
315            m.check_clash(self.info, seen)
316
317    def connect_doc(self, doc=None):
318        super().connect_doc(doc)
319        doc = doc or self.doc
320        for m in self.members:
321            m.connect_doc(doc)
322
323    def is_implicit(self):
324        # See QAPISchema._make_implicit_enum_type() and ._def_predefineds()
325        return self.name.endswith('Kind') or self.name == 'QType'
326
327    def c_type(self):
328        return c_name(self.name)
329
330    def member_names(self):
331        return [m.name for m in self.members]
332
333    def json_type(self):
334        return 'string'
335
336    def visit(self, visitor):
337        super().visit(visitor)
338        visitor.visit_enum_type(
339            self.name, self.info, self.ifcond, self.features,
340            self.members, self.prefix)
341
342
343class QAPISchemaArrayType(QAPISchemaType):
344    meta = 'array'
345
346    def __init__(self, name, info, element_type):
347        super().__init__(name, info, None)
348        assert isinstance(element_type, str)
349        self._element_type_name = element_type
350        self.element_type = None
351
352    def check(self, schema):
353        super().check(schema)
354        self.element_type = schema.resolve_type(
355            self._element_type_name, self.info,
356            self.info and self.info.defn_meta)
357        assert not isinstance(self.element_type, QAPISchemaArrayType)
358
359    def set_module(self, schema):
360        self._set_module(schema, self.element_type.info)
361
362    @property
363    def ifcond(self):
364        assert self._checked
365        return self.element_type.ifcond
366
367    def is_implicit(self):
368        return True
369
370    def c_type(self):
371        return c_name(self.name) + POINTER_SUFFIX
372
373    def json_type(self):
374        return 'array'
375
376    def doc_type(self):
377        elt_doc_type = self.element_type.doc_type()
378        if not elt_doc_type:
379            return None
380        return 'array of ' + elt_doc_type
381
382    def visit(self, visitor):
383        super().visit(visitor)
384        visitor.visit_array_type(self.name, self.info, self.ifcond,
385                                 self.element_type)
386
387    def describe(self):
388        assert self.meta
389        return "%s type ['%s']" % (self.meta, self._element_type_name)
390
391
392class QAPISchemaObjectType(QAPISchemaType):
393    def __init__(self, name, info, doc, ifcond, features,
394                 base, local_members, variants):
395        # struct has local_members, optional base, and no variants
396        # flat union has base, variants, and no local_members
397        # simple union has local_members, variants, and no base
398        super().__init__(name, info, doc, ifcond, features)
399        self.meta = 'union' if variants else 'struct'
400        assert base is None or isinstance(base, str)
401        for m in local_members:
402            assert isinstance(m, QAPISchemaObjectTypeMember)
403            m.set_defined_in(name)
404        if variants is not None:
405            assert isinstance(variants, QAPISchemaVariants)
406            variants.set_defined_in(name)
407        self._base_name = base
408        self.base = None
409        self.local_members = local_members
410        self.variants = variants
411        self.members = None
412
413    def check(self, schema):
414        # This calls another type T's .check() exactly when the C
415        # struct emitted by gen_object() contains that T's C struct
416        # (pointers don't count).
417        if self.members is not None:
418            # A previous .check() completed: nothing to do
419            return
420        if self._checked:
421            # Recursed: C struct contains itself
422            raise QAPISemError(self.info,
423                               "object %s contains itself" % self.name)
424
425        super().check(schema)
426        assert self._checked and self.members is None
427
428        seen = OrderedDict()
429        if self._base_name:
430            self.base = schema.resolve_type(self._base_name, self.info,
431                                            "'base'")
432            if (not isinstance(self.base, QAPISchemaObjectType)
433                    or self.base.variants):
434                raise QAPISemError(
435                    self.info,
436                    "'base' requires a struct type, %s isn't"
437                    % self.base.describe())
438            self.base.check(schema)
439            self.base.check_clash(self.info, seen)
440        for m in self.local_members:
441            m.check(schema)
442            m.check_clash(self.info, seen)
443        members = seen.values()
444
445        if self.variants:
446            self.variants.check(schema, seen)
447            self.variants.check_clash(self.info, seen)
448
449        self.members = members  # mark completed
450
451    # Check that the members of this type do not cause duplicate JSON members,
452    # and update seen to track the members seen so far. Report any errors
453    # on behalf of info, which is not necessarily self.info
454    def check_clash(self, info, seen):
455        assert self._checked
456        assert not self.variants       # not implemented
457        for m in self.members:
458            m.check_clash(info, seen)
459
460    def connect_doc(self, doc=None):
461        super().connect_doc(doc)
462        doc = doc or self.doc
463        if self.base and self.base.is_implicit():
464            self.base.connect_doc(doc)
465        for m in self.local_members:
466            m.connect_doc(doc)
467
468    @property
469    def ifcond(self):
470        assert self._checked
471        if isinstance(self._ifcond, QAPISchemaType):
472            # Simple union wrapper type inherits from wrapped type;
473            # see _make_implicit_object_type()
474            return self._ifcond.ifcond
475        return self._ifcond
476
477    def is_implicit(self):
478        # See QAPISchema._make_implicit_object_type(), as well as
479        # _def_predefineds()
480        return self.name.startswith('q_')
481
482    def is_empty(self):
483        assert self.members is not None
484        return not self.members and not self.variants
485
486    def c_name(self):
487        assert self.name != 'q_empty'
488        return super().c_name()
489
490    def c_type(self):
491        assert not self.is_implicit()
492        return c_name(self.name) + POINTER_SUFFIX
493
494    def c_unboxed_type(self):
495        return c_name(self.name)
496
497    def json_type(self):
498        return 'object'
499
500    def visit(self, visitor):
501        super().visit(visitor)
502        visitor.visit_object_type(
503            self.name, self.info, self.ifcond, self.features,
504            self.base, self.local_members, self.variants)
505        visitor.visit_object_type_flat(
506            self.name, self.info, self.ifcond, self.features,
507            self.members, self.variants)
508
509
510class QAPISchemaAlternateType(QAPISchemaType):
511    meta = 'alternate'
512
513    def __init__(self, name, info, doc, ifcond, features, variants):
514        super().__init__(name, info, doc, ifcond, features)
515        assert isinstance(variants, QAPISchemaVariants)
516        assert variants.tag_member
517        variants.set_defined_in(name)
518        variants.tag_member.set_defined_in(self.name)
519        self.variants = variants
520
521    def check(self, schema):
522        super().check(schema)
523        self.variants.tag_member.check(schema)
524        # Not calling self.variants.check_clash(), because there's nothing
525        # to clash with
526        self.variants.check(schema, {})
527        # Alternate branch names have no relation to the tag enum values;
528        # so we have to check for potential name collisions ourselves.
529        seen = {}
530        types_seen = {}
531        for v in self.variants.variants:
532            v.check_clash(self.info, seen)
533            qtype = v.type.alternate_qtype()
534            if not qtype:
535                raise QAPISemError(
536                    self.info,
537                    "%s cannot use %s"
538                    % (v.describe(self.info), v.type.describe()))
539            conflicting = set([qtype])
540            if qtype == 'QTYPE_QSTRING':
541                if isinstance(v.type, QAPISchemaEnumType):
542                    for m in v.type.members:
543                        if m.name in ['on', 'off']:
544                            conflicting.add('QTYPE_QBOOL')
545                        if re.match(r'[-+0-9.]', m.name):
546                            # lazy, could be tightened
547                            conflicting.add('QTYPE_QNUM')
548                else:
549                    conflicting.add('QTYPE_QNUM')
550                    conflicting.add('QTYPE_QBOOL')
551            for qt in conflicting:
552                if qt in types_seen:
553                    raise QAPISemError(
554                        self.info,
555                        "%s can't be distinguished from '%s'"
556                        % (v.describe(self.info), types_seen[qt]))
557                types_seen[qt] = v.name
558
559    def connect_doc(self, doc=None):
560        super().connect_doc(doc)
561        doc = doc or self.doc
562        for v in self.variants.variants:
563            v.connect_doc(doc)
564
565    def c_type(self):
566        return c_name(self.name) + POINTER_SUFFIX
567
568    def json_type(self):
569        return 'value'
570
571    def visit(self, visitor):
572        super().visit(visitor)
573        visitor.visit_alternate_type(
574            self.name, self.info, self.ifcond, self.features, self.variants)
575
576
577class QAPISchemaVariants:
578    def __init__(self, tag_name, info, tag_member, variants):
579        # Flat unions pass tag_name but not tag_member.
580        # Simple unions and alternates pass tag_member but not tag_name.
581        # After check(), tag_member is always set, and tag_name remains
582        # a reliable witness of being used by a flat union.
583        assert bool(tag_member) != bool(tag_name)
584        assert (isinstance(tag_name, str) or
585                isinstance(tag_member, QAPISchemaObjectTypeMember))
586        for v in variants:
587            assert isinstance(v, QAPISchemaVariant)
588        self._tag_name = tag_name
589        self.info = info
590        self.tag_member = tag_member
591        self.variants = variants
592
593    def set_defined_in(self, name):
594        for v in self.variants:
595            v.set_defined_in(name)
596
597    def check(self, schema, seen):
598        if not self.tag_member:  # flat union
599            self.tag_member = seen.get(c_name(self._tag_name))
600            base = "'base'"
601            # Pointing to the base type when not implicit would be
602            # nice, but we don't know it here
603            if not self.tag_member or self._tag_name != self.tag_member.name:
604                raise QAPISemError(
605                    self.info,
606                    "discriminator '%s' is not a member of %s"
607                    % (self._tag_name, base))
608            # Here we do:
609            base_type = schema.lookup_type(self.tag_member.defined_in)
610            assert base_type
611            if not base_type.is_implicit():
612                base = "base type '%s'" % self.tag_member.defined_in
613            if not isinstance(self.tag_member.type, QAPISchemaEnumType):
614                raise QAPISemError(
615                    self.info,
616                    "discriminator member '%s' of %s must be of enum type"
617                    % (self._tag_name, base))
618            if self.tag_member.optional:
619                raise QAPISemError(
620                    self.info,
621                    "discriminator member '%s' of %s must not be optional"
622                    % (self._tag_name, base))
623            if self.tag_member.ifcond.is_present():
624                raise QAPISemError(
625                    self.info,
626                    "discriminator member '%s' of %s must not be conditional"
627                    % (self._tag_name, base))
628        else:                   # simple union
629            assert isinstance(self.tag_member.type, QAPISchemaEnumType)
630            assert not self.tag_member.optional
631            assert not self.tag_member.ifcond.is_present()
632        if self._tag_name:    # flat union
633            # branches that are not explicitly covered get an empty type
634            cases = {v.name for v in self.variants}
635            for m in self.tag_member.type.members:
636                if m.name not in cases:
637                    v = QAPISchemaVariant(m.name, self.info,
638                                          'q_empty', m.ifcond)
639                    v.set_defined_in(self.tag_member.defined_in)
640                    self.variants.append(v)
641        if not self.variants:
642            raise QAPISemError(self.info, "union has no branches")
643        for v in self.variants:
644            v.check(schema)
645            # Union names must match enum values; alternate names are
646            # checked separately. Use 'seen' to tell the two apart.
647            if seen:
648                if v.name not in self.tag_member.type.member_names():
649                    raise QAPISemError(
650                        self.info,
651                        "branch '%s' is not a value of %s"
652                        % (v.name, self.tag_member.type.describe()))
653                if (not isinstance(v.type, QAPISchemaObjectType)
654                        or v.type.variants):
655                    raise QAPISemError(
656                        self.info,
657                        "%s cannot use %s"
658                        % (v.describe(self.info), v.type.describe()))
659                v.type.check(schema)
660
661    def check_clash(self, info, seen):
662        for v in self.variants:
663            # Reset seen map for each variant, since qapi names from one
664            # branch do not affect another branch
665            v.type.check_clash(info, dict(seen))
666
667
668class QAPISchemaMember:
669    """ Represents object members, enum members and features """
670    role = 'member'
671
672    def __init__(self, name, info, ifcond=None):
673        assert isinstance(name, str)
674        self.name = name
675        self.info = info
676        self.ifcond = ifcond or QAPISchemaIfCond()
677        self.defined_in = None
678
679    def set_defined_in(self, name):
680        assert not self.defined_in
681        self.defined_in = name
682
683    def check_clash(self, info, seen):
684        cname = c_name(self.name)
685        if cname in seen:
686            raise QAPISemError(
687                info,
688                "%s collides with %s"
689                % (self.describe(info), seen[cname].describe(info)))
690        seen[cname] = self
691
692    def connect_doc(self, doc):
693        if doc:
694            doc.connect_member(self)
695
696    def describe(self, info):
697        role = self.role
698        defined_in = self.defined_in
699        assert defined_in
700
701        if defined_in.startswith('q_obj_'):
702            # See QAPISchema._make_implicit_object_type() - reverse the
703            # mapping there to create a nice human-readable description
704            defined_in = defined_in[6:]
705            if defined_in.endswith('-arg'):
706                # Implicit type created for a command's dict 'data'
707                assert role == 'member'
708                role = 'parameter'
709            elif defined_in.endswith('-base'):
710                # Implicit type created for a flat union's dict 'base'
711                role = 'base ' + role
712            else:
713                # Implicit type created for a simple union's branch
714                assert defined_in.endswith('-wrapper')
715                # Unreachable and not implemented
716                assert False
717        elif defined_in.endswith('Kind'):
718            # See QAPISchema._make_implicit_enum_type()
719            # Implicit enum created for simple union's branches
720            assert role == 'value'
721            role = 'branch'
722        elif defined_in != info.defn_name:
723            return "%s '%s' of type '%s'" % (role, self.name, defined_in)
724        return "%s '%s'" % (role, self.name)
725
726
727class QAPISchemaEnumMember(QAPISchemaMember):
728    role = 'value'
729
730
731class QAPISchemaFeature(QAPISchemaMember):
732    role = 'feature'
733
734
735class QAPISchemaObjectTypeMember(QAPISchemaMember):
736    def __init__(self, name, info, typ, optional, ifcond=None, features=None):
737        super().__init__(name, info, ifcond)
738        assert isinstance(typ, str)
739        assert isinstance(optional, bool)
740        for f in features or []:
741            assert isinstance(f, QAPISchemaFeature)
742            f.set_defined_in(name)
743        self._type_name = typ
744        self.type = None
745        self.optional = optional
746        self.features = features or []
747
748    def check(self, schema):
749        assert self.defined_in
750        self.type = schema.resolve_type(self._type_name, self.info,
751                                        self.describe)
752        seen = {}
753        for f in self.features:
754            f.check_clash(self.info, seen)
755
756    def connect_doc(self, doc):
757        super().connect_doc(doc)
758        if doc:
759            for f in self.features:
760                doc.connect_feature(f)
761
762
763class QAPISchemaVariant(QAPISchemaObjectTypeMember):
764    role = 'branch'
765
766    def __init__(self, name, info, typ, ifcond=None):
767        super().__init__(name, info, typ, False, ifcond)
768
769
770class QAPISchemaCommand(QAPISchemaEntity):
771    meta = 'command'
772
773    def __init__(self, name, info, doc, ifcond, features,
774                 arg_type, ret_type,
775                 gen, success_response, boxed, allow_oob, allow_preconfig,
776                 coroutine):
777        super().__init__(name, info, doc, ifcond, features)
778        assert not arg_type or isinstance(arg_type, str)
779        assert not ret_type or isinstance(ret_type, str)
780        self._arg_type_name = arg_type
781        self.arg_type = None
782        self._ret_type_name = ret_type
783        self.ret_type = None
784        self.gen = gen
785        self.success_response = success_response
786        self.boxed = boxed
787        self.allow_oob = allow_oob
788        self.allow_preconfig = allow_preconfig
789        self.coroutine = coroutine
790
791    def check(self, schema):
792        super().check(schema)
793        if self._arg_type_name:
794            self.arg_type = schema.resolve_type(
795                self._arg_type_name, self.info, "command's 'data'")
796            if not isinstance(self.arg_type, QAPISchemaObjectType):
797                raise QAPISemError(
798                    self.info,
799                    "command's 'data' cannot take %s"
800                    % self.arg_type.describe())
801            if self.arg_type.variants and not self.boxed:
802                raise QAPISemError(
803                    self.info,
804                    "command's 'data' can take %s only with 'boxed': true"
805                    % self.arg_type.describe())
806        if self._ret_type_name:
807            self.ret_type = schema.resolve_type(
808                self._ret_type_name, self.info, "command's 'returns'")
809            if self.name not in self.info.pragma.command_returns_exceptions:
810                typ = self.ret_type
811                if isinstance(typ, QAPISchemaArrayType):
812                    typ = self.ret_type.element_type
813                    assert typ
814                if not isinstance(typ, QAPISchemaObjectType):
815                    raise QAPISemError(
816                        self.info,
817                        "command's 'returns' cannot take %s"
818                        % self.ret_type.describe())
819
820    def connect_doc(self, doc=None):
821        super().connect_doc(doc)
822        doc = doc or self.doc
823        if doc:
824            if self.arg_type and self.arg_type.is_implicit():
825                self.arg_type.connect_doc(doc)
826
827    def visit(self, visitor):
828        super().visit(visitor)
829        visitor.visit_command(
830            self.name, self.info, self.ifcond, self.features,
831            self.arg_type, self.ret_type, self.gen, self.success_response,
832            self.boxed, self.allow_oob, self.allow_preconfig,
833            self.coroutine)
834
835
836class QAPISchemaEvent(QAPISchemaEntity):
837    meta = 'event'
838
839    def __init__(self, name, info, doc, ifcond, features, arg_type, boxed):
840        super().__init__(name, info, doc, ifcond, features)
841        assert not arg_type or isinstance(arg_type, str)
842        self._arg_type_name = arg_type
843        self.arg_type = None
844        self.boxed = boxed
845
846    def check(self, schema):
847        super().check(schema)
848        if self._arg_type_name:
849            self.arg_type = schema.resolve_type(
850                self._arg_type_name, self.info, "event's 'data'")
851            if not isinstance(self.arg_type, QAPISchemaObjectType):
852                raise QAPISemError(
853                    self.info,
854                    "event's 'data' cannot take %s"
855                    % self.arg_type.describe())
856            if self.arg_type.variants and not self.boxed:
857                raise QAPISemError(
858                    self.info,
859                    "event's 'data' can take %s only with 'boxed': true"
860                    % self.arg_type.describe())
861
862    def connect_doc(self, doc=None):
863        super().connect_doc(doc)
864        doc = doc or self.doc
865        if doc:
866            if self.arg_type and self.arg_type.is_implicit():
867                self.arg_type.connect_doc(doc)
868
869    def visit(self, visitor):
870        super().visit(visitor)
871        visitor.visit_event(
872            self.name, self.info, self.ifcond, self.features,
873            self.arg_type, self.boxed)
874
875
876class QAPISchema:
877    def __init__(self, fname):
878        self.fname = fname
879
880        try:
881            parser = QAPISchemaParser(fname)
882        except OSError as err:
883            raise QAPIError(
884                f"can't read schema file '{fname}': {err.strerror}"
885            ) from err
886
887        exprs = check_exprs(parser.exprs)
888        self.docs = parser.docs
889        self._entity_list = []
890        self._entity_dict = {}
891        self._module_dict = OrderedDict()
892        self._schema_dir = os.path.dirname(fname)
893        self._make_module(QAPISchemaModule.BUILTIN_MODULE_NAME)
894        self._make_module(fname)
895        self._predefining = True
896        self._def_predefineds()
897        self._predefining = False
898        self._def_exprs(exprs)
899        self.check()
900
901    def _def_entity(self, ent):
902        # Only the predefined types are allowed to not have info
903        assert ent.info or self._predefining
904        self._entity_list.append(ent)
905        if ent.name is None:
906            return
907        # TODO reject names that differ only in '_' vs. '.'  vs. '-',
908        # because they're liable to clash in generated C.
909        other_ent = self._entity_dict.get(ent.name)
910        if other_ent:
911            if other_ent.info:
912                where = QAPISourceError(other_ent.info, "previous definition")
913                raise QAPISemError(
914                    ent.info,
915                    "'%s' is already defined\n%s" % (ent.name, where))
916            raise QAPISemError(
917                ent.info, "%s is already defined" % other_ent.describe())
918        self._entity_dict[ent.name] = ent
919
920    def lookup_entity(self, name, typ=None):
921        ent = self._entity_dict.get(name)
922        if typ and not isinstance(ent, typ):
923            return None
924        return ent
925
926    def lookup_type(self, name):
927        return self.lookup_entity(name, QAPISchemaType)
928
929    def resolve_type(self, name, info, what):
930        typ = self.lookup_type(name)
931        if not typ:
932            if callable(what):
933                what = what(info)
934            raise QAPISemError(
935                info, "%s uses unknown type '%s'" % (what, name))
936        return typ
937
938    def _module_name(self, fname: str) -> str:
939        if QAPISchemaModule.is_system_module(fname):
940            return fname
941        return os.path.relpath(fname, self._schema_dir)
942
943    def _make_module(self, fname):
944        name = self._module_name(fname)
945        if name not in self._module_dict:
946            self._module_dict[name] = QAPISchemaModule(name)
947        return self._module_dict[name]
948
949    def module_by_fname(self, fname):
950        name = self._module_name(fname)
951        return self._module_dict[name]
952
953    def _def_include(self, expr, info, doc):
954        include = expr['include']
955        assert doc is None
956        self._def_entity(QAPISchemaInclude(self._make_module(include), info))
957
958    def _def_builtin_type(self, name, json_type, c_type):
959        self._def_entity(QAPISchemaBuiltinType(name, json_type, c_type))
960        # Instantiating only the arrays that are actually used would
961        # be nice, but we can't as long as their generated code
962        # (qapi-builtin-types.[ch]) may be shared by some other
963        # schema.
964        self._make_array_type(name, None)
965
966    def _def_predefineds(self):
967        for t in [('str',    'string',  'char' + POINTER_SUFFIX),
968                  ('number', 'number',  'double'),
969                  ('int',    'int',     'int64_t'),
970                  ('int8',   'int',     'int8_t'),
971                  ('int16',  'int',     'int16_t'),
972                  ('int32',  'int',     'int32_t'),
973                  ('int64',  'int',     'int64_t'),
974                  ('uint8',  'int',     'uint8_t'),
975                  ('uint16', 'int',     'uint16_t'),
976                  ('uint32', 'int',     'uint32_t'),
977                  ('uint64', 'int',     'uint64_t'),
978                  ('size',   'int',     'uint64_t'),
979                  ('bool',   'boolean', 'bool'),
980                  ('any',    'value',   'QObject' + POINTER_SUFFIX),
981                  ('null',   'null',    'QNull' + POINTER_SUFFIX)]:
982            self._def_builtin_type(*t)
983        self.the_empty_object_type = QAPISchemaObjectType(
984            'q_empty', None, None, None, None, None, [], None)
985        self._def_entity(self.the_empty_object_type)
986
987        qtypes = ['none', 'qnull', 'qnum', 'qstring', 'qdict', 'qlist',
988                  'qbool']
989        qtype_values = self._make_enum_members(
990            [{'name': n} for n in qtypes], None)
991
992        self._def_entity(QAPISchemaEnumType('QType', None, None, None, None,
993                                            qtype_values, 'QTYPE'))
994
995    def _make_features(self, features, info):
996        if features is None:
997            return []
998        return [QAPISchemaFeature(f['name'], info,
999                                  QAPISchemaIfCond(f.get('if')))
1000                for f in features]
1001
1002    def _make_enum_members(self, values, info):
1003        return [QAPISchemaEnumMember(v['name'], info,
1004                                     QAPISchemaIfCond(v.get('if')))
1005                for v in values]
1006
1007    def _make_implicit_enum_type(self, name, info, ifcond, values):
1008        # See also QAPISchemaObjectTypeMember.describe()
1009        name = name + 'Kind'    # reserved by check_defn_name_str()
1010        self._def_entity(QAPISchemaEnumType(
1011            name, info, None, ifcond, None,
1012            self._make_enum_members(values, info),
1013            None))
1014        return name
1015
1016    def _make_array_type(self, element_type, info):
1017        name = element_type + 'List'    # reserved by check_defn_name_str()
1018        if not self.lookup_type(name):
1019            self._def_entity(QAPISchemaArrayType(name, info, element_type))
1020        return name
1021
1022    def _make_implicit_object_type(self, name, info, ifcond, role, members):
1023        if not members:
1024            return None
1025        # See also QAPISchemaObjectTypeMember.describe()
1026        name = 'q_obj_%s-%s' % (name, role)
1027        typ = self.lookup_entity(name, QAPISchemaObjectType)
1028        if typ:
1029            # The implicit object type has multiple users.  This is
1030            # either a duplicate definition (which will be flagged
1031            # later), or an implicit wrapper type used for multiple
1032            # simple unions.  In the latter case, ifcond should be the
1033            # disjunction of its user's ifconds.  Not implemented.
1034            # Instead, we always pass the wrapped type's ifcond, which
1035            # is trivially the same for all users.  It's also
1036            # necessary for the wrapper to compile.  But it's not
1037            # tight: the disjunction need not imply it.  We may end up
1038            # compiling useless wrapper types.
1039            # TODO kill simple unions or implement the disjunction
1040            pass
1041        else:
1042            self._def_entity(QAPISchemaObjectType(
1043                name, info, None, ifcond, None, None, members, None))
1044        return name
1045
1046    def _def_enum_type(self, expr, info, doc):
1047        name = expr['enum']
1048        data = expr['data']
1049        prefix = expr.get('prefix')
1050        ifcond = QAPISchemaIfCond(expr.get('if'))
1051        features = self._make_features(expr.get('features'), info)
1052        self._def_entity(QAPISchemaEnumType(
1053            name, info, doc, ifcond, features,
1054            self._make_enum_members(data, info), prefix))
1055
1056    def _make_member(self, name, typ, ifcond, features, info):
1057        optional = False
1058        if name.startswith('*'):
1059            name = name[1:]
1060            optional = True
1061        if isinstance(typ, list):
1062            assert len(typ) == 1
1063            typ = self._make_array_type(typ[0], info)
1064        return QAPISchemaObjectTypeMember(name, info, typ, optional, ifcond,
1065                                          self._make_features(features, info))
1066
1067    def _make_members(self, data, info):
1068        return [self._make_member(key, value['type'],
1069                                  QAPISchemaIfCond(value.get('if')),
1070                                  value.get('features'), info)
1071                for (key, value) in data.items()]
1072
1073    def _def_struct_type(self, expr, info, doc):
1074        name = expr['struct']
1075        base = expr.get('base')
1076        data = expr['data']
1077        ifcond = QAPISchemaIfCond(expr.get('if'))
1078        features = self._make_features(expr.get('features'), info)
1079        self._def_entity(QAPISchemaObjectType(
1080            name, info, doc, ifcond, features, base,
1081            self._make_members(data, info),
1082            None))
1083
1084    def _make_variant(self, case, typ, ifcond, info):
1085        return QAPISchemaVariant(case, info, typ, ifcond)
1086
1087    def _make_simple_variant(self, case, typ, ifcond, info):
1088        if isinstance(typ, list):
1089            assert len(typ) == 1
1090            typ = self._make_array_type(typ[0], info)
1091        typ = self._make_implicit_object_type(
1092            typ, info, self.lookup_type(typ),
1093            'wrapper', [self._make_member('data', typ, None, None, info)])
1094        return QAPISchemaVariant(case, info, typ, ifcond)
1095
1096    def _def_union_type(self, expr, info, doc):
1097        name = expr['union']
1098        data = expr['data']
1099        base = expr.get('base')
1100        ifcond = QAPISchemaIfCond(expr.get('if'))
1101        features = self._make_features(expr.get('features'), info)
1102        tag_name = expr.get('discriminator')
1103        tag_member = None
1104        if isinstance(base, dict):
1105            base = self._make_implicit_object_type(
1106                name, info, ifcond,
1107                'base', self._make_members(base, info))
1108        if tag_name:
1109            variants = [
1110                self._make_variant(key, value['type'],
1111                                   QAPISchemaIfCond(value.get('if')),
1112                                   info)
1113                for (key, value) in data.items()]
1114            members = []
1115        else:
1116            variants = [
1117                self._make_simple_variant(key, value['type'],
1118                                          QAPISchemaIfCond(value.get('if')),
1119                                          info)
1120                for (key, value) in data.items()]
1121            enum = [{'name': v.name, 'if': v.ifcond.ifcond} for v in variants]
1122            typ = self._make_implicit_enum_type(name, info, ifcond, enum)
1123            tag_member = QAPISchemaObjectTypeMember('type', info, typ, False)
1124            members = [tag_member]
1125        self._def_entity(
1126            QAPISchemaObjectType(name, info, doc, ifcond, features,
1127                                 base, members,
1128                                 QAPISchemaVariants(
1129                                     tag_name, info, tag_member, variants)))
1130
1131    def _def_alternate_type(self, expr, info, doc):
1132        name = expr['alternate']
1133        data = expr['data']
1134        ifcond = QAPISchemaIfCond(expr.get('if'))
1135        features = self._make_features(expr.get('features'), info)
1136        variants = [
1137            self._make_variant(key, value['type'],
1138                               QAPISchemaIfCond(value.get('if')),
1139                               info)
1140            for (key, value) in data.items()]
1141        tag_member = QAPISchemaObjectTypeMember('type', info, 'QType', False)
1142        self._def_entity(
1143            QAPISchemaAlternateType(name, info, doc, ifcond, features,
1144                                    QAPISchemaVariants(
1145                                        None, info, tag_member, variants)))
1146
1147    def _def_command(self, expr, info, doc):
1148        name = expr['command']
1149        data = expr.get('data')
1150        rets = expr.get('returns')
1151        gen = expr.get('gen', True)
1152        success_response = expr.get('success-response', True)
1153        boxed = expr.get('boxed', False)
1154        allow_oob = expr.get('allow-oob', False)
1155        allow_preconfig = expr.get('allow-preconfig', False)
1156        coroutine = expr.get('coroutine', False)
1157        ifcond = QAPISchemaIfCond(expr.get('if'))
1158        features = self._make_features(expr.get('features'), info)
1159        if isinstance(data, OrderedDict):
1160            data = self._make_implicit_object_type(
1161                name, info, ifcond,
1162                'arg', self._make_members(data, info))
1163        if isinstance(rets, list):
1164            assert len(rets) == 1
1165            rets = self._make_array_type(rets[0], info)
1166        self._def_entity(QAPISchemaCommand(name, info, doc, ifcond, features,
1167                                           data, rets,
1168                                           gen, success_response,
1169                                           boxed, allow_oob, allow_preconfig,
1170                                           coroutine))
1171
1172    def _def_event(self, expr, info, doc):
1173        name = expr['event']
1174        data = expr.get('data')
1175        boxed = expr.get('boxed', False)
1176        ifcond = QAPISchemaIfCond(expr.get('if'))
1177        features = self._make_features(expr.get('features'), info)
1178        if isinstance(data, OrderedDict):
1179            data = self._make_implicit_object_type(
1180                name, info, ifcond,
1181                'arg', self._make_members(data, info))
1182        self._def_entity(QAPISchemaEvent(name, info, doc, ifcond, features,
1183                                         data, boxed))
1184
1185    def _def_exprs(self, exprs):
1186        for expr_elem in exprs:
1187            expr = expr_elem['expr']
1188            info = expr_elem['info']
1189            doc = expr_elem.get('doc')
1190            if 'enum' in expr:
1191                self._def_enum_type(expr, info, doc)
1192            elif 'struct' in expr:
1193                self._def_struct_type(expr, info, doc)
1194            elif 'union' in expr:
1195                self._def_union_type(expr, info, doc)
1196            elif 'alternate' in expr:
1197                self._def_alternate_type(expr, info, doc)
1198            elif 'command' in expr:
1199                self._def_command(expr, info, doc)
1200            elif 'event' in expr:
1201                self._def_event(expr, info, doc)
1202            elif 'include' in expr:
1203                self._def_include(expr, info, doc)
1204            else:
1205                assert False
1206
1207    def check(self):
1208        for ent in self._entity_list:
1209            ent.check(self)
1210            ent.connect_doc()
1211            ent.check_doc()
1212        for ent in self._entity_list:
1213            ent.set_module(self)
1214
1215    def visit(self, visitor):
1216        visitor.visit_begin(self)
1217        for mod in self._module_dict.values():
1218            mod.visit(visitor)
1219        visitor.visit_end()
1220