Coverage for /opt/homebrew/lib/python3.11/site-packages/anyio/_core/_typedattr.py: 69%
36 statements
« prev ^ index » next coverage.py v7.2.3, created at 2023-05-04 13:14 +0700
« prev ^ index » next coverage.py v7.2.3, created at 2023-05-04 13:14 +0700
1import sys
2from typing import Any, Callable, Dict, Mapping, TypeVar, Union, overload
4from ._exceptions import TypedAttributeLookupError
6if sys.version_info >= (3, 8):
7 from typing import final
8else:
9 from typing_extensions import final
11T_Attr = TypeVar("T_Attr")
12T_Default = TypeVar("T_Default")
13undefined = object()
16def typed_attribute() -> Any:
17 """Return a unique object, used to mark typed attributes."""
18 return object()
21class TypedAttributeSet:
22 """
23 Superclass for typed attribute collections.
25 Checks that every public attribute of every subclass has a type annotation.
26 """
28 def __init_subclass__(cls) -> None:
29 annotations: Dict[str, Any] = getattr(cls, "__annotations__", {})
30 for attrname in dir(cls):
31 if not attrname.startswith("_") and attrname not in annotations:
32 raise TypeError(
33 f"Attribute {attrname!r} is missing its type annotation"
34 )
36 super().__init_subclass__()
39class TypedAttributeProvider:
40 """Base class for classes that wish to provide typed extra attributes."""
42 @property
43 def extra_attributes(self) -> Mapping[T_Attr, Callable[[], T_Attr]]:
44 """
45 A mapping of the extra attributes to callables that return the corresponding values.
47 If the provider wraps another provider, the attributes from that wrapper should also be
48 included in the returned mapping (but the wrapper may override the callables from the
49 wrapped instance).
51 """
52 return {}
54 @overload
55 def extra(self, attribute: T_Attr) -> T_Attr:
56 ...
58 @overload
59 def extra(self, attribute: T_Attr, default: T_Default) -> Union[T_Attr, T_Default]:
60 ...
62 @final
63 def extra(self, attribute: Any, default: object = undefined) -> object:
64 """
65 extra(attribute, default=undefined)
67 Return the value of the given typed extra attribute.
69 :param attribute: the attribute (member of a :class:`~TypedAttributeSet`) to look for
70 :param default: the value that should be returned if no value is found for the attribute
71 :raises ~anyio.TypedAttributeLookupError: if the search failed and no default value was
72 given
74 """
75 try:
76 return self.extra_attributes[attribute]()
77 except KeyError:
78 if default is undefined:
79 raise TypedAttributeLookupError("Attribute not found") from None
80 else:
81 return default