Initial commit

venv/Lib/site-packages/propcache/_helpers_py.py

@@ -0,0 +1,56 @@
+"""Various helper functions."""
+
+import sys
+from functools import cached_property
+from typing import Any, Callable, Generic, Optional, Protocol, TypeVar, Union, overload
+
+__all__ = ("under_cached_property", "cached_property")
+
+
+if sys.version_info >= (3, 11):
+    from typing import Self
+else:
+    Self = Any
+
+_T = TypeVar("_T")
+
+
+class _TSelf(Protocol, Generic[_T]):
+    _cache: dict[str, _T]
+
+
+class under_cached_property(Generic[_T]):
+    """Use as a class method decorator.
+
+    It operates almost exactly like
+    the Python `@property` decorator, but it puts the result of the
+    method it decorates into the instance dict after the first call,
+    effectively replacing the function it decorates with an instance
+    variable.  It is, in Python parlance, a data descriptor.
+    """
+
+    def __init__(self, wrapped: Callable[..., _T]) -> None:
+        self.wrapped = wrapped
+        self.__doc__ = wrapped.__doc__
+        self.name = wrapped.__name__
+
+    @overload
+    def __get__(self, inst: None, owner: Optional[type[object]] = None) -> Self: ...
+
+    @overload
+    def __get__(self, inst: _TSelf[_T], owner: Optional[type[object]] = None) -> _T: ...
+
+    def __get__(
+        self, inst: Optional[_TSelf[_T]], owner: Optional[type[object]] = None
+    ) -> Union[_T, Self]:
+        if inst is None:
+            return self
+        try:
+            return inst._cache[self.name]
+        except KeyError:
+            val = self.wrapped(inst)
+            inst._cache[self.name] = val
+            return val
+
+    def __set__(self, inst: _TSelf[_T], value: _T) -> None:
+        raise AttributeError("cached property is read-only")