Reduce code for registry items with a base class (#114689)

homeassistant/helpers/registry.py

@@ -3,7 +3,9 @@
 from __future__ import annotations
 
 from abc import ABC, abstractmethod
-from typing import TYPE_CHECKING, Any
+from collections import UserDict
+from collections.abc import ValuesView
+from typing import TYPE_CHECKING, Any, Literal, TypeVar
 
 from homeassistant.core import CoreState, HomeAssistant, callback
 
@@ -14,6 +16,54 @@ SAVE_DELAY = 10
 SAVE_DELAY_LONG = 180
 
 
+_DataT = TypeVar("_DataT")
+
+
+class BaseRegistryItems(UserDict[str, _DataT], ABC):
+    """Base class for registry items."""
+
+    data: dict[str, _DataT]
+
+    def values(self) -> ValuesView[_DataT]:
+        """Return the underlying values to avoid __iter__ overhead."""
+        return self.data.values()
+
+    @abstractmethod
+    def _index_entry(self, key: str, entry: _DataT) -> None:
+        """Index an entry."""
+
+    @abstractmethod
+    def _unindex_entry(self, key: str, replacement_entry: _DataT | None = None) -> None:
+        """Unindex an entry."""
+
+    def __setitem__(self, key: str, entry: _DataT) -> None:
+        """Add an item."""
+        data = self.data
+        if key in data:
+            self._unindex_entry(key, entry)
+        data[key] = entry
+        self._index_entry(key, entry)
+
+    def _unindex_entry_value(
+        self, key: str, value: str, index: dict[str, dict[str, Literal[True]]]
+    ) -> None:
+        """Unindex an entry value.
+
+        key is the entry key
+        value is the value to unindex such as config_entry_id or device_id.
+        index is the index to unindex from.
+        """
+        entries = index[value]
+        del entries[key]
+        if not entries:
+            del index[value]
+
+    def __delitem__(self, key: str) -> None:
+        """Remove an item."""
+        self._unindex_entry(key)
+        super().__delitem__(key)
+
+
 class BaseRegistry(ABC):
     """Class to implement a registry."""