Refactor beatmap import secondary process

Doesn't launch a new game window and now supports several files at once.

osu.Desktop/Program.cs

@@ -2,6 +2,9 @@
 //Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
 
 using System;
+using System.IO;
+using System.Linq;
+using osu.Framework;
 using osu.Framework.Desktop;
 using osu.Framework.Platform;
 using osu.Game;
@@ -11,11 +14,22 @@ namespace osu.Desktop
     public static class Program
     {
         [STAThread]
-        public static void Main(string[] args)
+        public static int Main(string[] args)
         {
             BasicGameHost host = Host.GetSuitableHost(@"osu");
-            host.Add(new OsuGame(args));
+            BaseGame osuGame = new OsuGame();
+            if (args.Length != 0 && args.All(File.Exists))
+            {
+                host.Load(osuGame);
+                var beatmapIPC = new IpcChannel<OsuGame.ImportBeatmap>(host);
+                foreach (var file in args)
+                    beatmapIPC.SendMessage(new OsuGame.ImportBeatmap { Path = file }).Wait();
+                Console.WriteLine(@"Sent file to running instance");
+                return 0;
+            }
+            host.Add(osuGame);
             host.Run();
+            return 0;
         }
     }
 }

osu.Game/OsuGame.cs

@@ -28,7 +28,7 @@ namespace osu.Game
 {
     public class OsuGame : OsuGameBase
     {
-        private class ImportBeatmap
+        public class ImportBeatmap
         {
             public string Path;
         }
@@ -37,16 +37,10 @@ private class ImportBeatmap
         public ChatConsole Chat;
         public MainMenu MainMenu => intro?.ChildGameMode as MainMenu;
         private Intro intro;
-        private string[] args;
         private IpcChannel<ImportBeatmap> BeatmapIPC;
 
         public Bindable<PlayMode> PlayMode;
 
-        public OsuGame(string[] args)
-        {
-            this.args = args;
-        }
-
         public override void SetHost(BasicGameHost host)
         {
             base.SetHost(host);
@@ -60,13 +54,7 @@ public override void Load(BaseGame game)
 
             if (!Host.IsPrimaryInstance)
             {
-                if (args.Length == 1 && File.Exists(args[0]))
-                {
-                    BeatmapIPC.SendMessage(new ImportBeatmap { Path = args[0] }).Wait();
-                    Logger.Log(@"Sent file to running instance");
-                }
-                else
-                    Logger.Log(@"osu! does not support multiple running instances.", LoggingTarget.Runtime, LogLevel.Error);
+                Logger.Log(@"osu! does not support multiple running instances.", LoggingTarget.Runtime, LogLevel.Error);
                 Environment.Exit(0);
             }
 

osu.Game/OsuGameBase.cs

@@ -72,8 +72,11 @@ protected override void Update()
         protected override void Dispose(bool isDisposing)
         {
             //refresh token may have changed.
-            Config.Set(OsuConfig.Token, API.Token);
-            Config.Save();
+            if (Config != null && API != null)
+            {
+                Config.Set(OsuConfig.Token, API.Token);
+                Config.Save();
+            }
 
             base.Dispose(isDisposing);
         }