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[PATCH v6 10/19] qapi/introspect.py: create a typed 'Annotated' data str
From: |
John Snow |
Subject: |
[PATCH v6 10/19] qapi/introspect.py: create a typed 'Annotated' data strutcure |
Date: |
Mon, 15 Feb 2021 21:18:00 -0500 |
Presently, we use a tuple to attach a dict containing annotations
(comments and compile-time conditionals) to a tree node. This is
undesirable because dicts are difficult to strongly type; promoting it
to a real class allows us to name the values and types of the
annotations we are expecting.
In terms of typing, the Annotated<T> type serves as a generic container
where the annotated node's type is preserved, allowing for greater
specificity than we'd be able to provide without a generic.
Signed-off-by: John Snow <jsnow@redhat.com>
---
scripts/qapi/introspect.py | 78 ++++++++++++++++++++++----------------
1 file changed, 45 insertions(+), 33 deletions(-)
diff --git a/scripts/qapi/introspect.py b/scripts/qapi/introspect.py
index 3c37c138013..5224be1a333 100644
--- a/scripts/qapi/introspect.py
+++ b/scripts/qapi/introspect.py
@@ -13,8 +13,12 @@
from typing import (
Any,
Dict,
+ Generic,
+ Iterable,
List,
Optional,
+ Tuple,
+ TypeVar,
Union,
)
@@ -52,15 +56,25 @@
_Scalar = Union[str, bool, None]
_NonScalar = Union[Dict[str, _Stub], List[_Stub]]
_Value = Union[_Scalar, _NonScalar]
-# JSONValue = TODO, in a forthcoming commit.
+JSONValue = Union[_Value, 'Annotated[_Value]']
-def _make_tree(obj, ifcond, comment=None):
- extra = {
- 'if': ifcond,
- 'comment': comment
- }
- return (obj, extra)
+_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: Iterable[str],
+ comment: Optional[str] = None):
+ self.value = value
+ self.comment: Optional[str] = comment
+ self.ifcond: Tuple[str, ...] = tuple(ifcond)
def _tree_to_qlit(obj, level=0, dict_value=False):
@@ -68,24 +82,20 @@ def _tree_to_qlit(obj, level=0, dict_value=False):
def indent(level):
return level * 4 * ' '
- if isinstance(obj, tuple):
- ifobj, extra = obj
- ifcond = extra.get('if')
- comment = extra.get('comment')
-
+ 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 comment:
- ret += indent(level) + '/* %s */\n' % comment
- if ifcond:
- ret += gen_if(ifcond)
- ret += _tree_to_qlit(ifobj, level)
- if ifcond:
- ret += '\n' + gen_endif(ifcond)
+ if obj.comment:
+ ret += indent(level) + '/* %s */\n' % obj.comment
+ if obj.ifcond:
+ ret += gen_if(obj.ifcond)
+ ret += _tree_to_qlit(obj.value, level)
+ if obj.ifcond:
+ ret += '\n' + gen_endif(obj.ifcond)
return ret
ret = ''
@@ -202,7 +212,7 @@ def _use_type(self, typ):
@staticmethod
def _gen_features(features):
- return [_make_tree(f.name, f.ifcond) for f in features]
+ return [Annotated(f.name, f.ifcond) for f in features]
def _gen_tree(self, name, mtype, obj, ifcond, features):
comment: Optional[str] = None
@@ -216,7 +226,7 @@ def _gen_tree(self, name, mtype, obj, ifcond, features):
obj['meta-type'] = mtype
if features:
obj['features'] = self._gen_features(features)
- self._trees.append(_make_tree(obj, ifcond, comment))
+ self._trees.append(Annotated(obj, ifcond, comment))
def _gen_member(self, member):
obj = {'name': member.name, 'type': self._use_type(member.type)}
@@ -224,7 +234,7 @@ def _gen_member(self, member):
obj['default'] = None
if member.features:
obj['features'] = self._gen_features(member.features)
- return _make_tree(obj, member.ifcond)
+ return Annotated(obj, member.ifcond)
def _gen_variants(self, tag_name, variants):
return {'tag': tag_name,
@@ -232,16 +242,17 @@ def _gen_variants(self, tag_name, variants):
def _gen_variant(self, variant):
obj = {'case': variant.name, 'type': self._use_type(variant.type)}
- return _make_tree(obj, variant.ifcond)
+ return Annotated(obj, variant.ifcond)
def visit_builtin_type(self, name, info, json_type):
self._gen_tree(name, 'builtin', {'json-type': json_type}, [], None)
def visit_enum_type(self, name, info, ifcond, features, members, prefix):
- self._gen_tree(name, 'enum',
- {'values': [_make_tree(m.name, m.ifcond, None)
- for m in members]},
- ifcond, features)
+ self._gen_tree(
+ name, 'enum',
+ {'values': [Annotated(m.name, m.ifcond) for m in members]},
+ ifcond, features
+ )
def visit_array_type(self, name, info, ifcond, element_type):
element = self._use_type(element_type)
@@ -258,12 +269,13 @@ def visit_object_type_flat(self, name, info, ifcond,
features,
self._gen_tree(name, 'object', obj, ifcond, features)
def visit_alternate_type(self, name, info, ifcond, features, variants):
- self._gen_tree(name, 'alternate',
- {'members': [
- _make_tree({'type': self._use_type(m.type)},
- m.ifcond, None)
- for m in variants.variants]},
- ifcond, features)
+ 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, info, ifcond, features,
arg_type, ret_type, gen, success_response, boxed,
--
2.29.2
- [PATCH v6 14/19] qapi/introspect.py: add type hint annotations, (continued)
- [PATCH v6 15/19] qapi/introspect.py: Add docstrings to _gen_tree and _tree_to_qlit, John Snow, 2021/02/15
- [PATCH v6 17/19] qapi/introspect.py: Type _gen_tree variants as Sequence[str], John Snow, 2021/02/15
- [PATCH v6 07/19] qapi/introspect.py: replace 'extra' dict with 'comment' argument, John Snow, 2021/02/15
- [PATCH v6 10/19] qapi/introspect.py: create a typed 'Annotated' data strutcure,
John Snow <=
- [PATCH v6 19/19] qapi/introspect.py: add SchemaMetaType enum, John Snow, 2021/02/15
[PATCH v6 16/19] qapi/introspect.py: Update copyright and authors list, John Snow, 2021/02/15
[PATCH v6 18/19] qapi/introspect.py: set _gen_tree's default ifcond argument to (), John Snow, 2021/02/15