xref: /qemu/scripts/qapi/introspect.py (revision 159fb790) 
1"""
2QAPI introspection generator
3
4Copyright (C) 2015-2021 Red Hat, Inc.
5
6Authors:
7 Markus Armbruster <armbru@redhat.com>
8 John Snow <jsnow@redhat.com>
9
10This work is licensed under the terms of the GNU GPL, version 2.
11See the COPYING file in the top-level directory.
12"""
13
14from typing import (
15    Any,
16    Dict,
17    Generic,
18    List,
19    Optional,
20    Sequence,
21    TypeVar,
22    Union,
23)
24
25from .common import c_name, mcgen
26from .gen import QAPISchemaMonolithicCVisitor
27from .schema import (
28    QAPISchema,
29    QAPISchemaArrayType,
30    QAPISchemaBuiltinType,
31    QAPISchemaEntity,
32    QAPISchemaEnumMember,
33    QAPISchemaFeature,
34    QAPISchemaIfCond,
35    QAPISchemaObjectType,
36    QAPISchemaObjectTypeMember,
37    QAPISchemaType,
38    QAPISchemaVariant,
39    QAPISchemaVariants,
40)
41from .source import QAPISourceInfo
42
43
44# This module constructs a tree data structure that is used to
45# generate the introspection information for QEMU. It is shaped
46# like a JSON value.
47#
48# A complexity over JSON is that our values may or may not be annotated.
49#
50# Un-annotated values may be:
51#     Scalar: str, bool, None.
52#     Non-scalar: List, Dict
53# _value = Union[str, bool, None, Dict[str, JSONValue], List[JSONValue]]
54#
55# With optional annotations, the type of all values is:
56# JSONValue = Union[_Value, Annotated[_Value]]
57#
58# Sadly, mypy does not support recursive types; so the _Stub alias is used to
59# mark the imprecision in the type model where we'd otherwise use JSONValue.
60_Stub = Any
61_Scalar = Union[str, bool, None]
62_NonScalar = Union[Dict[str, _Stub], List[_Stub]]
63_Value = Union[_Scalar, _NonScalar]
64JSONValue = Union[_Value, 'Annotated[_Value]']
65
66# These types are based on structures defined in QEMU's schema, so we
67# lack precise types for them here. Python 3.6 does not offer
68# TypedDict constructs, so they are broadly typed here as simple
69# Python Dicts.
70SchemaInfo = Dict[str, object]
71SchemaInfoEnumMember = Dict[str, object]
72SchemaInfoObject = Dict[str, object]
73SchemaInfoObjectVariant = Dict[str, object]
74SchemaInfoObjectMember = Dict[str, object]
75SchemaInfoCommand = Dict[str, object]
76
77
78_ValueT = TypeVar('_ValueT', bound=_Value)
79
80
81class Annotated(Generic[_ValueT]):
82    """
83    Annotated generally contains a SchemaInfo-like type (as a dict),
84    But it also used to wrap comments/ifconds around scalar leaf values,
85    for the benefit of features and enums.
86    """
87    # TODO: Remove after Python 3.7 adds @dataclass:
88    # pylint: disable=too-few-public-methods
89    def __init__(self, value: _ValueT, ifcond: QAPISchemaIfCond,
90                 comment: Optional[str] = None):
91        self.value = value
92        self.comment: Optional[str] = comment
93        self.ifcond = ifcond
94
95
96def _tree_to_qlit(obj: JSONValue,
97                  level: int = 0,
98                  dict_value: bool = False) -> str:
99    """
100    Convert the type tree into a QLIT C string, recursively.
101
102    :param obj: The value to convert.
103                This value may not be Annotated when dict_value is True.
104    :param level: The indentation level for this particular value.
105    :param dict_value: True when the value being processed belongs to a
106                       dict key; which suppresses the output indent.
107    """
108
109    def indent(level: int) -> str:
110        return level * 4 * ' '
111
112    if isinstance(obj, Annotated):
113        # NB: _tree_to_qlit is called recursively on the values of a
114        # key:value pair; those values can't be decorated with
115        # comments or conditionals.
116        msg = "dict values cannot have attached comments or if-conditionals."
117        assert not dict_value, msg
118
119        ret = ''
120        if obj.comment:
121            ret += indent(level) + f"/* {obj.comment} */\n"
122        if obj.ifcond.is_present():
123            ret += obj.ifcond.gen_if()
124        ret += _tree_to_qlit(obj.value, level)
125        if obj.ifcond.is_present():
126            ret += '\n' + obj.ifcond.gen_endif()
127        return ret
128
129    ret = ''
130    if not dict_value:
131        ret += indent(level)
132
133    # Scalars:
134    if obj is None:
135        ret += 'QLIT_QNULL'
136    elif isinstance(obj, str):
137        ret += f"QLIT_QSTR({to_c_string(obj)})"
138    elif isinstance(obj, bool):
139        ret += f"QLIT_QBOOL({str(obj).lower()})"
140
141    # Non-scalars:
142    elif isinstance(obj, list):
143        ret += 'QLIT_QLIST(((QLitObject[]) {\n'
144        for value in obj:
145            ret += _tree_to_qlit(value, level + 1).strip('\n') + '\n'
146        ret += indent(level + 1) + '{}\n'
147        ret += indent(level) + '}))'
148    elif isinstance(obj, dict):
149        ret += 'QLIT_QDICT(((QLitDictEntry[]) {\n'
150        for key, value in sorted(obj.items()):
151            ret += indent(level + 1) + "{{ {:s}, {:s} }},\n".format(
152                to_c_string(key),
153                _tree_to_qlit(value, level + 1, dict_value=True)
154            )
155        ret += indent(level + 1) + '{}\n'
156        ret += indent(level) + '}))'
157    else:
158        raise NotImplementedError(
159            f"type '{type(obj).__name__}' not implemented"
160        )
161
162    if level > 0:
163        ret += ','
164    return ret
165
166
167def to_c_string(string: str) -> str:
168    return '"' + string.replace('\\', r'\\').replace('"', r'\"') + '"'
169
170
171class QAPISchemaGenIntrospectVisitor(QAPISchemaMonolithicCVisitor):
172
173    def __init__(self, prefix: str, unmask: bool):
174        super().__init__(
175            prefix, 'qapi-introspect',
176            ' * QAPI/QMP schema introspection', __doc__)
177        self._unmask = unmask
178        self._schema: Optional[QAPISchema] = None
179        self._trees: List[Annotated[SchemaInfo]] = []
180        self._used_types: List[QAPISchemaType] = []
181        self._name_map: Dict[str, str] = {}
182        self._genc.add(mcgen('''
183#include "qemu/osdep.h"
184#include "%(prefix)sqapi-introspect.h"
185
186''',
187                             prefix=prefix))
188
189    def visit_begin(self, schema: QAPISchema) -> None:
190        self._schema = schema
191
192    def visit_end(self) -> None:
193        # visit the types that are actually used
194        for typ in self._used_types:
195            typ.visit(self)
196        # generate C
197        name = c_name(self._prefix, protect=False) + 'qmp_schema_qlit'
198        self._genh.add(mcgen('''
199#include "qapi/qmp/qlit.h"
200
201extern const QLitObject %(c_name)s;
202''',
203                             c_name=c_name(name)))
204        self._genc.add(mcgen('''
205const QLitObject %(c_name)s = %(c_string)s;
206''',
207                             c_name=c_name(name),
208                             c_string=_tree_to_qlit(self._trees)))
209        self._schema = None
210        self._trees = []
211        self._used_types = []
212        self._name_map = {}
213
214    def visit_needed(self, entity: QAPISchemaEntity) -> bool:
215        # Ignore types on first pass; visit_end() will pick up used types
216        return not isinstance(entity, QAPISchemaType)
217
218    def _name(self, name: str) -> str:
219        if self._unmask:
220            return name
221        if name not in self._name_map:
222            self._name_map[name] = '%d' % len(self._name_map)
223        return self._name_map[name]
224
225    def _use_type(self, typ: QAPISchemaType) -> str:
226        assert self._schema is not None
227
228        # Map the various integer types to plain int
229        if typ.json_type() == 'int':
230            type_int = self._schema.lookup_type('int')
231            assert type_int
232            typ = type_int
233        elif (isinstance(typ, QAPISchemaArrayType) and
234              typ.element_type.json_type() == 'int'):
235            type_intList = self._schema.lookup_type('intList')
236            assert type_intList
237            typ = type_intList
238        # Add type to work queue if new
239        if typ not in self._used_types:
240            self._used_types.append(typ)
241        # Clients should examine commands and events, not types.  Hide
242        # type names as integers to reduce the temptation.  Also, it
243        # saves a few characters on the wire.
244        if isinstance(typ, QAPISchemaBuiltinType):
245            return typ.name
246        if isinstance(typ, QAPISchemaArrayType):
247            return '[' + self._use_type(typ.element_type) + ']'
248        return self._name(typ.name)
249
250    @staticmethod
251    def _gen_features(features: Sequence[QAPISchemaFeature]
252                      ) -> List[Annotated[str]]:
253        return [Annotated(f.name, f.ifcond) for f in features]
254
255    def _gen_tree(self, name: str, mtype: str, obj: Dict[str, object],
256                  ifcond: QAPISchemaIfCond = QAPISchemaIfCond(),
257                  features: Sequence[QAPISchemaFeature] = ()) -> None:
258        """
259        Build and append a SchemaInfo object to self._trees.
260
261        :param name: The SchemaInfo's name.
262        :param mtype: The SchemaInfo's meta-type.
263        :param obj: Additional SchemaInfo members, as appropriate for
264                    the meta-type.
265        :param ifcond: Conditionals to apply to the SchemaInfo.
266        :param features: The SchemaInfo's features.
267                         Will be omitted from the output if empty.
268        """
269        comment: Optional[str] = None
270        if mtype not in ('command', 'event', 'builtin', 'array'):
271            if not self._unmask:
272                # Output a comment to make it easy to map masked names
273                # back to the source when reading the generated output.
274                comment = f'"{self._name(name)}" = {name}'
275            name = self._name(name)
276        obj['name'] = name
277        obj['meta-type'] = mtype
278        if features:
279            obj['features'] = self._gen_features(features)
280        self._trees.append(Annotated(obj, ifcond, comment))
281
282    def _gen_enum_member(self, member: QAPISchemaEnumMember
283                         ) -> Annotated[SchemaInfoEnumMember]:
284        obj: SchemaInfoEnumMember = {
285            'name': member.name,
286        }
287        if member.features:
288            obj['features'] = self._gen_features(member.features)
289        return Annotated(obj, member.ifcond)
290
291    def _gen_object_member(self, member: QAPISchemaObjectTypeMember
292                           ) -> Annotated[SchemaInfoObjectMember]:
293        obj: SchemaInfoObjectMember = {
294            'name': member.name,
295            'type': self._use_type(member.type)
296        }
297        if member.optional:
298            obj['default'] = None
299        if member.features:
300            obj['features'] = self._gen_features(member.features)
301        return Annotated(obj, member.ifcond)
302
303    def _gen_variant(self, variant: QAPISchemaVariant
304                     ) -> Annotated[SchemaInfoObjectVariant]:
305        obj: SchemaInfoObjectVariant = {
306            'case': variant.name,
307            'type': self._use_type(variant.type)
308        }
309        return Annotated(obj, variant.ifcond)
310
311    def visit_builtin_type(self, name: str, info: Optional[QAPISourceInfo],
312                           json_type: str) -> None:
313        self._gen_tree(name, 'builtin', {'json-type': json_type})
314
315    def visit_enum_type(self, name: str, info: Optional[QAPISourceInfo],
316                        ifcond: QAPISchemaIfCond,
317                        features: List[QAPISchemaFeature],
318                        members: List[QAPISchemaEnumMember],
319                        prefix: Optional[str]) -> None:
320        self._gen_tree(
321            name, 'enum',
322            {'members': [self._gen_enum_member(m) for m in members],
323             'values': [Annotated(m.name, m.ifcond) for m in members]},
324            ifcond, features
325        )
326
327    def visit_array_type(self, name: str, info: Optional[QAPISourceInfo],
328                         ifcond: QAPISchemaIfCond,
329                         element_type: QAPISchemaType) -> None:
330        element = self._use_type(element_type)
331        self._gen_tree('[' + element + ']', 'array', {'element-type': element},
332                       ifcond)
333
334    def visit_object_type_flat(self, name: str, info: Optional[QAPISourceInfo],
335                               ifcond: QAPISchemaIfCond,
336                               features: List[QAPISchemaFeature],
337                               members: List[QAPISchemaObjectTypeMember],
338                               variants: Optional[QAPISchemaVariants]) -> None:
339        obj: SchemaInfoObject = {
340            'members': [self._gen_object_member(m) for m in members]
341        }
342        if variants:
343            obj['tag'] = variants.tag_member.name
344            obj['variants'] = [self._gen_variant(v) for v in variants.variants]
345        self._gen_tree(name, 'object', obj, ifcond, features)
346
347    def visit_alternate_type(self, name: str, info: Optional[QAPISourceInfo],
348                             ifcond: QAPISchemaIfCond,
349                             features: List[QAPISchemaFeature],
350                             variants: QAPISchemaVariants) -> None:
351        self._gen_tree(
352            name, 'alternate',
353            {'members': [Annotated({'type': self._use_type(m.type)},
354                                   m.ifcond)
355                         for m in variants.variants]},
356            ifcond, features
357        )
358
359    def visit_command(self, name: str, info: Optional[QAPISourceInfo],
360                      ifcond: QAPISchemaIfCond,
361                      features: List[QAPISchemaFeature],
362                      arg_type: Optional[QAPISchemaObjectType],
363                      ret_type: Optional[QAPISchemaType], gen: bool,
364                      success_response: bool, boxed: bool, allow_oob: bool,
365                      allow_preconfig: bool, coroutine: bool) -> None:
366        assert self._schema is not None
367
368        arg_type = arg_type or self._schema.the_empty_object_type
369        ret_type = ret_type or self._schema.the_empty_object_type
370        obj: SchemaInfoCommand = {
371            'arg-type': self._use_type(arg_type),
372            'ret-type': self._use_type(ret_type)
373        }
374        if allow_oob:
375            obj['allow-oob'] = allow_oob
376        self._gen_tree(name, 'command', obj, ifcond, features)
377
378    def visit_event(self, name: str, info: Optional[QAPISourceInfo],
379                    ifcond: QAPISchemaIfCond,
380                    features: List[QAPISchemaFeature],
381                    arg_type: Optional[QAPISchemaObjectType],
382                    boxed: bool) -> None:
383        assert self._schema is not None
384
385        arg_type = arg_type or self._schema.the_empty_object_type
386        self._gen_tree(name, 'event', {'arg-type': self._use_type(arg_type)},
387                       ifcond, features)
388
389
390def gen_introspect(schema: QAPISchema, output_dir: str, prefix: str,
391                   opt_unmask: bool) -> None:
392    vis = QAPISchemaGenIntrospectVisitor(prefix, opt_unmask)
393    schema.visit(vis)
394    vis.write(output_dir)
395