From b520efb87ae422faba8d2fcddecd201865fe1df0 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Wed, 24 Apr 2024 09:56:59 +0200
Subject: [PATCH] Small speed up to async_track_event (#116083)

---
 homeassistant/helpers/event.py | 36 +++++++++++++---------------------
 1 file changed, 14 insertions(+), 22 deletions(-)

diff --git a/homeassistant/helpers/event.py b/homeassistant/helpers/event.py
index 7fae0976686..5cffe992c0d 100644
--- a/homeassistant/helpers/event.py
+++ b/homeassistant/helpers/event.py
@@ -3,11 +3,12 @@
 from __future__ import annotations
 
 import asyncio
+from collections import defaultdict
 from collections.abc import Callable, Coroutine, Iterable, Mapping, Sequence
 import copy
 from dataclasses import dataclass
 from datetime import datetime, timedelta
-import functools as ft
+from functools import partial, wraps
 import logging
 from random import randint
 import time
@@ -161,7 +162,7 @@ def threaded_listener_factory(
 ) -> Callable[Concatenate[HomeAssistant, _P], CALLBACK_TYPE]:
     """Convert an async event helper to a threaded one."""
 
-    @ft.wraps(async_factory)
+    @wraps(async_factory)
     def factory(
         hass: HomeAssistant, *args: _P.args, **kwargs: _P.kwargs
     ) -> CALLBACK_TYPE:
@@ -170,7 +171,7 @@ def threaded_listener_factory(
             raise TypeError("First parameter needs to be a hass instance")
 
         async_remove = run_callback_threadsafe(
-            hass.loop, ft.partial(async_factory, hass, *args, **kwargs)
+            hass.loop, partial(async_factory, hass, *args, **kwargs)
         ).result()
 
         def remove() -> None:
@@ -409,19 +410,16 @@ def _async_track_event(
         return _remove_empty_listener
 
     hass_data = hass.data
-    callbacks_key = tracker.callbacks_key
-
-    callbacks: dict[str, list[HassJob[[Event[_TypedDictT]], Any]]] | None
-    if not (callbacks := hass_data.get(callbacks_key)):
-        callbacks = hass_data[callbacks_key] = {}
+    callbacks: defaultdict[str, list[HassJob[[Event[_TypedDictT]], Any]]] | None
+    if not (callbacks := hass_data.get(tracker.callbacks_key)):
+        callbacks = hass_data[tracker.callbacks_key] = defaultdict(list)
 
     listeners_key = tracker.listeners_key
-
-    if listeners_key not in hass_data:
-        hass_data[listeners_key] = hass.bus.async_listen(
+    if tracker.listeners_key not in hass_data:
+        hass_data[tracker.listeners_key] = hass.bus.async_listen(
             tracker.event_type,
-            ft.partial(tracker.dispatcher_callable, hass, callbacks),
-            event_filter=ft.partial(tracker.filter_callable, hass, callbacks),
+            partial(tracker.dispatcher_callable, hass, callbacks),
+            event_filter=partial(tracker.filter_callable, hass, callbacks),
         )
 
     job = HassJob(action, f"track {tracker.event_type} event {keys}", job_type=job_type)
@@ -432,19 +430,13 @@ def _async_track_event(
         # here because this function gets called ~20000 times
         # during startup, and we want to avoid the overhead of
         # creating empty lists and throwing them away.
-        if callback_list := callbacks.get(keys):
-            callback_list.append(job)
-        else:
-            callbacks[keys] = [job]
+        callbacks[keys].append(job)
         keys = [keys]
     else:
         for key in keys:
-            if callback_list := callbacks.get(key):
-                callback_list.append(job)
-            else:
-                callbacks[key] = [job]
+            callbacks[key].append(job)
 
-    return ft.partial(_remove_listener, hass, listeners_key, keys, job, callbacks)
+    return partial(_remove_listener, hass, listeners_key, keys, job, callbacks)
 
 
 @callback