Загрузить файлы в «venv/Lib/site-packages/anyio/_core»

venv/Lib/site-packages/anyio/_core/_typedattr.py

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+from __future__ import annotations
+
+from collections.abc import Callable, Mapping
+from typing import Any, TypeVar, final, overload
+
+from ._exceptions import TypedAttributeLookupError
+
+T_Attr = TypeVar("T_Attr")
+T_Default = TypeVar("T_Default")
+undefined = object()
+
+
+def typed_attribute() -> Any:
+    """Return a unique object, used to mark typed attributes."""
+    return object()
+
+
+class TypedAttributeSet:
+    """
+    Superclass for typed attribute collections.
+
+    Checks that every public attribute of every subclass has a type annotation.
+    """
+
+    def __init_subclass__(cls) -> None:
+        annotations: dict[str, Any] = getattr(cls, "__annotations__", {})
+        for attrname in dir(cls):
+            if not attrname.startswith("_") and attrname not in annotations:
+                raise TypeError(
+                    f"Attribute {attrname!r} is missing its type annotation"
+                )
+
+        super().__init_subclass__()
+
+
+class TypedAttributeProvider:
+    """Base class for classes that wish to provide typed extra attributes."""
+
+    @property
+    def extra_attributes(self) -> Mapping[T_Attr, Callable[[], T_Attr]]:
+        """
+        A mapping of the extra attributes to callables that return the corresponding
+        values.
+
+        If the provider wraps another provider, the attributes from that wrapper should
+        also be included in the returned mapping (but the wrapper may override the
+        callables from the wrapped instance).
+
+        """
+        return {}
+
+    @overload
+    def extra(self, attribute: T_Attr) -> T_Attr: ...
+
+    @overload
+    def extra(self, attribute: T_Attr, default: T_Default) -> T_Attr | T_Default: ...
+
+    @final
+    def extra(self, attribute: Any, default: object = undefined) -> object:
+        """
+        extra(attribute, default=undefined)
+
+        Return the value of the given typed extra attribute.
+
+        :param attribute: the attribute (member of a :class:`~TypedAttributeSet`) to
+            look for
+        :param default: the value that should be returned if no value is found for the
+            attribute
+        :raises ~anyio.TypedAttributeLookupError: if the search failed and no default
+            value was given
+
+        """
+        try:
+            getter = self.extra_attributes[attribute]
+        except KeyError:
+            if default is undefined:
+                raise TypedAttributeLookupError("Attribute not found") from None
+            else:
+                return default
+
+        return getter()