Introduce Virtio-loopback epsilon release:

Epsilon release introduces a new compatibility layer which make virtio-loopback
design to work with QEMU and rust-vmm vhost-user backend without require any
changes.

Signed-off-by: Timos Ampelikiotis <t.ampelikiotis@virtualopensystems.com>
Change-Id: I52e57563e08a7d0bdc002f8e928ee61ba0c53dd9

1 files changed, 390 insertions, 0 deletions

diff --git a/scripts/qapi/introspect.py b/scripts/qapi/introspect.py
new file mode 100644
index 000000000..67c7d89aa
--- /dev/null
+++ b/scripts/qapi/introspect.py
@@ -0,0 +1,390 @@
+"""
+QAPI introspection generator
+
+Copyright (C) 2015-2021 Red Hat, Inc.
+
+Authors:
+ Markus Armbruster <armbru@redhat.com>
+ John Snow <jsnow@redhat.com>
+
+This work is licensed under the terms of the GNU GPL, version 2.
+See the COPYING file in the top-level directory.
+"""
+
+from typing import (
+    Any,
+    Dict,
+    Generic,
+    List,
+    Optional,
+    Sequence,
+    TypeVar,
+    Union,
+)
+
+from .common import c_name, mcgen
+from .gen import QAPISchemaMonolithicCVisitor
+from .schema import (
+    QAPISchema,
+    QAPISchemaArrayType,
+    QAPISchemaBuiltinType,
+    QAPISchemaEntity,
+    QAPISchemaEnumMember,
+    QAPISchemaFeature,
+    QAPISchemaIfCond,
+    QAPISchemaObjectType,
+    QAPISchemaObjectTypeMember,
+    QAPISchemaType,
+    QAPISchemaVariant,
+    QAPISchemaVariants,
+)
+from .source import QAPISourceInfo
+
+
+# This module constructs a tree data structure that is used to
+# generate the introspection information for QEMU. It is shaped
+# like a JSON value.
+#
+# A complexity over JSON is that our values may or may not be annotated.
+#
+# Un-annotated values may be:
+#     Scalar: str, bool, None.
+#     Non-scalar: List, Dict
+# _value = Union[str, bool, None, Dict[str, JSONValue], List[JSONValue]]
+#
+# With optional annotations, the type of all values is:
+# JSONValue = Union[_Value, Annotated[_Value]]
+#
+# Sadly, mypy does not support recursive types; so the _Stub alias is used to
+# mark the imprecision in the type model where we'd otherwise use JSONValue.
+_Stub = Any
+_Scalar = Union[str, bool, None]
+_NonScalar = Union[Dict[str, _Stub], List[_Stub]]
+_Value = Union[_Scalar, _NonScalar]
+JSONValue = Union[_Value, 'Annotated[_Value]']
+
+# These types are based on structures defined in QEMU's schema, so we
+# lack precise types for them here. Python 3.6 does not offer
+# TypedDict constructs, so they are broadly typed here as simple
+# Python Dicts.
+SchemaInfo = Dict[str, object]
+SchemaInfoEnumMember = Dict[str, object]
+SchemaInfoObject = Dict[str, object]
+SchemaInfoObjectVariant = Dict[str, object]
+SchemaInfoObjectMember = Dict[str, object]
+SchemaInfoCommand = Dict[str, object]
+
+
+_ValueT = TypeVar('_ValueT', bound=_Value)
+
+
+class Annotated(Generic[_ValueT]):
+    """
+    Annotated generally contains a SchemaInfo-like type (as a dict),
+    But it also used to wrap comments/ifconds around scalar leaf values,
+    for the benefit of features and enums.
+    """
+    # TODO: Remove after Python 3.7 adds @dataclass:
+    # pylint: disable=too-few-public-methods
+    def __init__(self, value: _ValueT, ifcond: QAPISchemaIfCond,
+                 comment: Optional[str] = None):
+        self.value = value
+        self.comment: Optional[str] = comment
+        self.ifcond = ifcond
+
+
+def _tree_to_qlit(obj: JSONValue,
+                  level: int = 0,
+                  dict_value: bool = False) -> str:
+    """
+    Convert the type tree into a QLIT C string, recursively.
+
+    :param obj: The value to convert.
+                This value may not be Annotated when dict_value is True.
+    :param level: The indentation level for this particular value.
+    :param dict_value: True when the value being processed belongs to a
+                       dict key; which suppresses the output indent.
+    """
+
+    def indent(level: int) -> str:
+        return level * 4 * ' '
+
+    if isinstance(obj, Annotated):
+        # NB: _tree_to_qlit is called recursively on the values of a
+        # key:value pair; those values can't be decorated with
+        # comments or conditionals.
+        msg = "dict values cannot have attached comments or if-conditionals."
+        assert not dict_value, msg
+
+        ret = ''
+        if obj.comment:
+            ret += indent(level) + f"/* {obj.comment} */\n"
+        if obj.ifcond.is_present():
+            ret += obj.ifcond.gen_if()
+        ret += _tree_to_qlit(obj.value, level)
+        if obj.ifcond.is_present():
+            ret += '\n' + obj.ifcond.gen_endif()
+        return ret
+
+    ret = ''
+    if not dict_value:
+        ret += indent(level)
+
+    # Scalars:
+    if obj is None:
+        ret += 'QLIT_QNULL'
+    elif isinstance(obj, str):
+        ret += f"QLIT_QSTR({to_c_string(obj)})"
+    elif isinstance(obj, bool):
+        ret += f"QLIT_QBOOL({str(obj).lower()})"
+
+    # Non-scalars:
+    elif isinstance(obj, list):
+        ret += 'QLIT_QLIST(((QLitObject[]) {\n'
+        for value in obj:
+            ret += _tree_to_qlit(value, level + 1).strip('\n') + '\n'
+        ret += indent(level + 1) + '{}\n'
+        ret += indent(level) + '}))'
+    elif isinstance(obj, dict):
+        ret += 'QLIT_QDICT(((QLitDictEntry[]) {\n'
+        for key, value in sorted(obj.items()):
+            ret += indent(level + 1) + "{{ {:s}, {:s} }},\n".format(
+                to_c_string(key),
+                _tree_to_qlit(value, level + 1, dict_value=True)
+            )
+        ret += indent(level + 1) + '{}\n'
+        ret += indent(level) + '}))'
+    else:
+        raise NotImplementedError(
+            f"type '{type(obj).__name__}' not implemented"
+        )
+
+    if level > 0:
+        ret += ','
+    return ret
+
+
+def to_c_string(string: str) -> str:
+    return '"' + string.replace('\\', r'\\').replace('"', r'\"') + '"'
+
+
+class QAPISchemaGenIntrospectVisitor(QAPISchemaMonolithicCVisitor):
+
+    def __init__(self, prefix: str, unmask: bool):
+        super().__init__(
+            prefix, 'qapi-introspect',
+            ' * QAPI/QMP schema introspection', __doc__)
+        self._unmask = unmask
+        self._schema: Optional[QAPISchema] = None
+        self._trees: List[Annotated[SchemaInfo]] = []
+        self._used_types: List[QAPISchemaType] = []
+        self._name_map: Dict[str, str] = {}
+        self._genc.add(mcgen('''
+#include "qemu/osdep.h"
+#include "%(prefix)sqapi-introspect.h"
+
+''',
+                             prefix=prefix))
+
+    def visit_begin(self, schema: QAPISchema) -> None:
+        self._schema = schema
+
+    def visit_end(self) -> None:
+        # visit the types that are actually used
+        for typ in self._used_types:
+            typ.visit(self)
+        # generate C
+        name = c_name(self._prefix, protect=False) + 'qmp_schema_qlit'
+        self._genh.add(mcgen('''
+#include "qapi/qmp/qlit.h"
+
+extern const QLitObject %(c_name)s;
+''',
+                             c_name=c_name(name)))
+        self._genc.add(mcgen('''
+const QLitObject %(c_name)s = %(c_string)s;
+''',
+                             c_name=c_name(name),
+                             c_string=_tree_to_qlit(self._trees)))
+        self._schema = None
+        self._trees = []
+        self._used_types = []
+        self._name_map = {}
+
+    def visit_needed(self, entity: QAPISchemaEntity) -> bool:
+        # Ignore types on first pass; visit_end() will pick up used types
+        return not isinstance(entity, QAPISchemaType)
+
+    def _name(self, name: str) -> str:
+        if self._unmask:
+            return name
+        if name not in self._name_map:
+            self._name_map[name] = '%d' % len(self._name_map)
+        return self._name_map[name]
+
+    def _use_type(self, typ: QAPISchemaType) -> str:
+        assert self._schema is not None
+
+        # Map the various integer types to plain int
+        if typ.json_type() == 'int':
+            typ = self._schema.lookup_type('int')
+        elif (isinstance(typ, QAPISchemaArrayType) and
+              typ.element_type.json_type() == 'int'):
+            typ = self._schema.lookup_type('intList')
+        # Add type to work queue if new
+        if typ not in self._used_types:
+            self._used_types.append(typ)
+        # Clients should examine commands and events, not types.  Hide
+        # type names as integers to reduce the temptation.  Also, it
+        # saves a few characters on the wire.
+        if isinstance(typ, QAPISchemaBuiltinType):
+            return typ.name
+        if isinstance(typ, QAPISchemaArrayType):
+            return '[' + self._use_type(typ.element_type) + ']'
+        return self._name(typ.name)
+
+    @staticmethod
+    def _gen_features(features: Sequence[QAPISchemaFeature]
+                      ) -> List[Annotated[str]]:
+        return [Annotated(f.name, f.ifcond) for f in features]
+
+    def _gen_tree(self, name: str, mtype: str, obj: Dict[str, object],
+                  ifcond: QAPISchemaIfCond = QAPISchemaIfCond(),
+                  features: Sequence[QAPISchemaFeature] = ()) -> None:
+        """
+        Build and append a SchemaInfo object to self._trees.
+
+        :param name: The SchemaInfo's name.
+        :param mtype: The SchemaInfo's meta-type.
+        :param obj: Additional SchemaInfo members, as appropriate for
+                    the meta-type.
+        :param ifcond: Conditionals to apply to the SchemaInfo.
+        :param features: The SchemaInfo's features.
+                         Will be omitted from the output if empty.
+        """
+        comment: Optional[str] = None
+        if mtype not in ('command', 'event', 'builtin', 'array'):
+            if not self._unmask:
+                # Output a comment to make it easy to map masked names
+                # back to the source when reading the generated output.
+                comment = f'"{self._name(name)}" = {name}'
+            name = self._name(name)
+        obj['name'] = name
+        obj['meta-type'] = mtype
+        if features:
+            obj['features'] = self._gen_features(features)
+        self._trees.append(Annotated(obj, ifcond, comment))
+
+    def _gen_enum_member(self, member: QAPISchemaEnumMember
+                         ) -> Annotated[SchemaInfoEnumMember]:
+        obj: SchemaInfoEnumMember = {
+            'name': member.name,
+        }
+        if member.features:
+            obj['features'] = self._gen_features(member.features)
+        return Annotated(obj, member.ifcond)
+
+    def _gen_object_member(self, member: QAPISchemaObjectTypeMember
+                           ) -> Annotated[SchemaInfoObjectMember]:
+        obj: SchemaInfoObjectMember = {
+            'name': member.name,
+            'type': self._use_type(member.type)
+        }
+        if member.optional:
+            obj['default'] = None
+        if member.features:
+            obj['features'] = self._gen_features(member.features)
+        return Annotated(obj, member.ifcond)
+
+    def _gen_variant(self, variant: QAPISchemaVariant
+                     ) -> Annotated[SchemaInfoObjectVariant]:
+        obj: SchemaInfoObjectVariant = {
+            'case': variant.name,
+            'type': self._use_type(variant.type)
+        }
+        return Annotated(obj, variant.ifcond)
+
+    def visit_builtin_type(self, name: str, info: Optional[QAPISourceInfo],
+                           json_type: str) -> None:
+        self._gen_tree(name, 'builtin', {'json-type': json_type})
+
+    def visit_enum_type(self, name: str, info: Optional[QAPISourceInfo],
+                        ifcond: QAPISchemaIfCond,
+                        features: List[QAPISchemaFeature],
+                        members: List[QAPISchemaEnumMember],
+                        prefix: Optional[str]) -> None:
+        self._gen_tree(
+            name, 'enum',
+            {'members': [self._gen_enum_member(m) for m in members],
+             'values': [Annotated(m.name, m.ifcond) for m in members]},
+            ifcond, features
+        )
+
+    def visit_array_type(self, name: str, info: Optional[QAPISourceInfo],
+                         ifcond: QAPISchemaIfCond,
+                         element_type: QAPISchemaType) -> None:
+        element = self._use_type(element_type)
+        self._gen_tree('[' + element + ']', 'array', {'element-type': element},
+                       ifcond)
+
+    def visit_object_type_flat(self, name: str, info: Optional[QAPISourceInfo],
+                               ifcond: QAPISchemaIfCond,
+                               features: List[QAPISchemaFeature],
+                               members: List[QAPISchemaObjectTypeMember],
+                               variants: Optional[QAPISchemaVariants]) -> None:
+        obj: SchemaInfoObject = {
+            'members': [self._gen_object_member(m) for m in members]
+        }
+        if variants:
+            obj['tag'] = variants.tag_member.name
+            obj['variants'] = [self._gen_variant(v) for v in variants.variants]
+        self._gen_tree(name, 'object', obj, ifcond, features)
+
+    def visit_alternate_type(self, name: str, info: Optional[QAPISourceInfo],
+                             ifcond: QAPISchemaIfCond,
+                             features: List[QAPISchemaFeature],
+                             variants: QAPISchemaVariants) -> None:
+        self._gen_tree(
+            name, 'alternate',
+            {'members': [Annotated({'type': self._use_type(m.type)},
+                                   m.ifcond)
+                         for m in variants.variants]},
+            ifcond, features
+        )
+
+    def visit_command(self, name: str, info: Optional[QAPISourceInfo],
+                      ifcond: QAPISchemaIfCond,
+                      features: List[QAPISchemaFeature],
+                      arg_type: Optional[QAPISchemaObjectType],
+                      ret_type: Optional[QAPISchemaType], gen: bool,
+                      success_response: bool, boxed: bool, allow_oob: bool,
+                      allow_preconfig: bool, coroutine: bool) -> None:
+        assert self._schema is not None
+
+        arg_type = arg_type or self._schema.the_empty_object_type
+        ret_type = ret_type or self._schema.the_empty_object_type
+        obj: SchemaInfoCommand = {
+            'arg-type': self._use_type(arg_type),
+            'ret-type': self._use_type(ret_type)
+        }
+        if allow_oob:
+            obj['allow-oob'] = allow_oob
+        self._gen_tree(name, 'command', obj, ifcond, features)
+
+    def visit_event(self, name: str, info: Optional[QAPISourceInfo],
+                    ifcond: QAPISchemaIfCond,
+                    features: List[QAPISchemaFeature],
+                    arg_type: Optional[QAPISchemaObjectType],
+                    boxed: bool) -> None:
+        assert self._schema is not None
+
+        arg_type = arg_type or self._schema.the_empty_object_type
+        self._gen_tree(name, 'event', {'arg-type': self._use_type(arg_type)},
+                       ifcond, features)
+
+
+def gen_introspect(schema: QAPISchema, output_dir: str, prefix: str,
+                   opt_unmask: bool) -> None:
+    vis = QAPISchemaGenIntrospectVisitor(prefix, opt_unmask)
+    schema.visit(vis)
+    vis.write(output_dir)