Drop _OpenSlideCacheWrapper

We don't want to encourage library users to duck-type a replacement for
OpenSlideCache, since any replacement would inherently need to make
assumptions about our implementation details.

Signed-off-by: Benjamin Gilbert <[email protected]>

Author: bgilbert

openslide/__init__.py

@@ -28,7 +28,7 @@
 from io import BytesIO
 from pathlib import Path
 from types import TracebackType
-from typing import Iterator, Literal, Mapping, Protocol, TypeVar
+from typing import Iterator, Literal, Mapping, TypeVar
 
 from PIL import Image, ImageCms
 
@@ -63,10 +63,6 @@
 _T = TypeVar('_T')
 
 
-class _OpenSlideCacheWrapper(Protocol):
-    _openslide_cache: lowlevel._OpenSlideCache
-
-
 class AbstractSlide:
     """The base class of a slide object."""
 
@@ -156,7 +152,7 @@ def read_region(
         size:     (width, height) tuple giving the region size."""
         raise NotImplementedError
 
-    def set_cache(self, cache: _OpenSlideCacheWrapper) -> None:
+    def set_cache(self, cache: OpenSlideCache) -> None:
         """Use the specified cache to store recently decoded slide tiles.
 
         cache: an OpenSlideCache object."""
@@ -278,7 +274,7 @@ def read_region(
             region.info['icc_profile'] = self._profile
         return region
 
-    def set_cache(self, cache: _OpenSlideCacheWrapper) -> None:
+    def set_cache(self, cache: OpenSlideCache) -> None:
         """Use the specified cache to store recently decoded slide tiles.
 
         By default, the object has a private cache with a default size.
@@ -480,7 +476,7 @@ def read_region(
             tile.info['icc_profile'] = self._profile
         return tile
 
-    def set_cache(self, cache: _OpenSlideCacheWrapper) -> None:
+    def set_cache(self, cache: OpenSlideCache) -> None:
         """Use the specified cache to store recently decoded slide tiles.
 
         ImageSlide does not support caching, so this method does nothing.