From 9923c1b6e6e33fc982c3e61c457aa5210da3ae73 Mon Sep 17 00:00:00 2001
From: Salman Ahmed <frenzibyte@gmail.com>
Date: Sun, 4 Feb 2024 17:08:39 +0300
Subject: [PATCH 1/3] Fix multiplayer/playlists lounge screen disposing rooms
 synchronously

---
 .../OnlinePlay/Lounge/Components/RoomsContainer.cs  | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/osu.Game/Screens/OnlinePlay/Lounge/Components/RoomsContainer.cs b/osu.Game/Screens/OnlinePlay/Lounge/Components/RoomsContainer.cs
index ac6403bb34..8a3fbbf792 100644
--- a/osu.Game/Screens/OnlinePlay/Lounge/Components/RoomsContainer.cs
+++ b/osu.Game/Screens/OnlinePlay/Lounge/Components/RoomsContainer.cs
@@ -141,9 +141,18 @@ namespace osu.Game.Screens.OnlinePlay.Lounge.Components
 
         private void removeRooms(IEnumerable<Room> rooms)
         {
-            foreach (var r in rooms)
+            foreach (var room in rooms)
             {
-                roomFlow.RemoveAll(d => d.Room == r, true);
+                var drawableRoom = roomFlow.SingleOrDefault(d => d.Room == room);
+                if (drawableRoom == null)
+                    continue;
+
+                // expire to trigger async disposal. the room still has to exist somewhere so we move it to internal content of RoomsContainer until next frame.
+                drawableRoom.Hide();
+                drawableRoom.Expire();
+
+                roomFlow.Remove(drawableRoom, false);
+                AddInternal(drawableRoom);
 
                 // selection may have a lease due to being in a sub screen.
                 if (!SelectedRoom.Disabled)

From 858f2fc7495867a600631e8683cefb193cc255fc Mon Sep 17 00:00:00 2001
From: Salman Ahmed <frenzibyte@gmail.com>
Date: Mon, 5 Feb 2024 18:39:04 +0300
Subject: [PATCH 2/3] Use `Clear` to trigger async disposal

---
 .../Lounge/Components/RoomsContainer.cs       | 28 +++++++++++--------
 1 file changed, 16 insertions(+), 12 deletions(-)

diff --git a/osu.Game/Screens/OnlinePlay/Lounge/Components/RoomsContainer.cs b/osu.Game/Screens/OnlinePlay/Lounge/Components/RoomsContainer.cs
index 8a3fbbf792..fd9aa6cb0e 100644
--- a/osu.Game/Screens/OnlinePlay/Lounge/Components/RoomsContainer.cs
+++ b/osu.Game/Screens/OnlinePlay/Lounge/Components/RoomsContainer.cs
@@ -126,7 +126,11 @@ namespace osu.Game.Screens.OnlinePlay.Lounge.Components
                 case NotifyCollectionChangedAction.Remove:
                     Debug.Assert(args.OldItems != null);
 
-                    removeRooms(args.OldItems.Cast<Room>());
+                    if (args.OldItems.Count == roomFlow.Count)
+                        clearRooms();
+                    else
+                        removeRooms(args.OldItems.Cast<Room>());
+
                     break;
             }
         }
@@ -141,18 +145,9 @@ namespace osu.Game.Screens.OnlinePlay.Lounge.Components
 
         private void removeRooms(IEnumerable<Room> rooms)
         {
-            foreach (var room in rooms)
+            foreach (var r in rooms)
             {
-                var drawableRoom = roomFlow.SingleOrDefault(d => d.Room == room);
-                if (drawableRoom == null)
-                    continue;
-
-                // expire to trigger async disposal. the room still has to exist somewhere so we move it to internal content of RoomsContainer until next frame.
-                drawableRoom.Hide();
-                drawableRoom.Expire();
-
-                roomFlow.Remove(drawableRoom, false);
-                AddInternal(drawableRoom);
+                roomFlow.RemoveAll(d => d.Room == r, true);
 
                 // selection may have a lease due to being in a sub screen.
                 if (!SelectedRoom.Disabled)
@@ -160,6 +155,15 @@ namespace osu.Game.Screens.OnlinePlay.Lounge.Components
             }
         }
 
+        private void clearRooms()
+        {
+            roomFlow.Clear();
+
+            // selection may have a lease due to being in a sub screen.
+            if (!SelectedRoom.Disabled)
+                SelectedRoom.Value = null;
+        }
+
         private void updateSorting()
         {
             foreach (var room in roomFlow)

From 791423651640174323beef88c9607d5cde01690b Mon Sep 17 00:00:00 2001
From: Salman Ahmed <frenzibyte@gmail.com>
Date: Mon, 5 Feb 2024 18:49:59 +0300
Subject: [PATCH 3/3] Add explanatory note

---
 osu.Game/Screens/OnlinePlay/Lounge/Components/RoomsContainer.cs | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/osu.Game/Screens/OnlinePlay/Lounge/Components/RoomsContainer.cs b/osu.Game/Screens/OnlinePlay/Lounge/Components/RoomsContainer.cs
index fd9aa6cb0e..bff1a8c64c 100644
--- a/osu.Game/Screens/OnlinePlay/Lounge/Components/RoomsContainer.cs
+++ b/osu.Game/Screens/OnlinePlay/Lounge/Components/RoomsContainer.cs
@@ -126,6 +126,8 @@ namespace osu.Game.Screens.OnlinePlay.Lounge.Components
                 case NotifyCollectionChangedAction.Remove:
                     Debug.Assert(args.OldItems != null);
 
+                    // clear operations have a separate path that benefits from async disposal,
+                    // since disposing is quite expensive when performed on a high number of drawables synchronously.
                     if (args.OldItems.Count == roomFlow.Count)
                         clearRooms();
                     else