Add libgamemode support

osu.Game/Gamemode/Gamemode.cs

@@ -0,0 +1,34 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using System.Runtime.InteropServices;
+
+namespace Gamemode
+{
+    public static class GamemodeRequest {
+
+        [DllImport("libgamemode.so.0")]
+        private static extern int real_gamemode_request_start();
+
+        [DllImport("libgamemode.so.0")]
+        private static extern int real_gamemode_request_end();
+
+        public static int RequestStart()
+        {
+            try {
+                return real_gamemode_request_start();
+            } catch {
+                return -1;
+            }
+        }
+
+        public static int RequestEnd()
+        {
+            try {
+                return real_gamemode_request_end();
+            } catch {
+                return -1;
+            }
+        }
+    }
+}

osu.Game/Screens/Play/PlayerLoader.cs

@@ -4,10 +4,12 @@
 using System;
 using System.Diagnostics;
 using System.Threading.Tasks;
+using Gamemode;
 using JetBrains.Annotations;
 using osu.Framework.Allocation;
 using osu.Framework.Audio;
 using osu.Framework.Bindables;
+using osu.Framework.Logging;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
 using osu.Framework.Graphics.Sprites;
@@ -195,6 +197,8 @@ public override void OnEntering(IScreen last)
             // this will continue to execute even after resuming back on restart.
             Scheduler.Add(new ScheduledDelegate(pushWhenLoaded, Clock.CurrentTime + 1800, 0));
 
+            Logger.Log($"Gamemode \"Start\" request exited with code {GamemodeRequest.RequestStart()}");
+
             showMuteWarningIfNeeded();
         }
 
@@ -234,6 +238,8 @@ public override bool OnExiting(IScreen next)
             BackgroundBrightnessReduction = false;
             Beatmap.Value.Track.RemoveAdjustment(AdjustableProperty.Volume, volumeAdjustment);
 
+            Logger.Log($"Gamemode \"End\" request exited with code {GamemodeRequest.RequestEnd()}");
+
             return base.OnExiting(next);
         }