feat(Settings): save config to disk periodically

Osu.Patcher.Hook/Patches/PatchOptions.cs

@@ -21,6 +21,11 @@ public abstract class PatchOptions
     /// </summary>
     public abstract void Load(Settings config);
 
+    /// <summary>
+    ///     When called, save current internal state to the target config to be saved.
+    /// </summary>
+    public abstract void Save(Settings config);
+
     /// <summary>
     ///     Finds and initializes an instance of every single type extending <see cref="PatchOptions" />.
     /// </summary>

Osu.Patcher.Hook/Patches/PatcherOptions/SaveOptions.cs

@@ -0,0 +1,34 @@
+using System.IO;
+using System.Reflection;
+using HarmonyLib;
+using JetBrains.Annotations;
+using Osu.Stubs.Helpers;
+using Osu.Utils;
+
+namespace Osu.Patcher.Hook.Patches.PatcherOptions;
+
+/// <summary>
+///     Hooks osu!'s datastore saving mechanism to save our own options every so often.
+/// </summary>
+[OsuPatch]
+[HarmonyPatch]
+[UsedImplicitly]
+internal static class SaveOptions
+{
+    [UsedImplicitly]
+    [HarmonyTargetMethod]
+    private static MethodBase Target() => DataStoreUpdater.Save.Reference;
+
+    [UsedImplicitly]
+    [HarmonyPostfix]
+    internal static void Save()
+    {
+        var osuDir = Path.GetDirectoryName(OsuAssembly.Assembly.Location)!;
+        var settings = new Settings();
+
+        // Write settings to this instance
+        Hook.PatchOptions.Do(opts => opts.Save(settings));
+
+        Settings.WriteToDisk(settings, osuDir);
+    }
+}

Osu.Patcher.Hook/Settings.cs

@@ -2,6 +2,7 @@
 using System.Diagnostics;
 using System.IO;
 using System.Xml.Serialization;
+using Osu.Patcher.Hook.Patches.LivePerformance;
 
 namespace Osu.Patcher.Hook;
 
@@ -46,6 +47,28 @@ public static Settings ReadFromDisk(string osuDir)
         }
     }
 
+    /// <summary>
+    ///     Handles writing the patcher options to disk.
+    /// </summary>
+    public static void WriteToDisk(Settings settings, string osuDir)
+    {
+        Debug.WriteLine("Writing patcher config to disk");
+
+        Directory.CreateDirectory(osuDir);
+
+        var file = Path.Combine(osuDir, OptionsFilename);
+        using var fs = File.OpenWrite(file);
+
+        try
+        {
+            Serializer.Serialize(fs, settings);
+        }
+        catch (Exception e)
+        {
+            Console.WriteLine($"Failed to write config to disk: {e}");
+        }
+    }
+
     #region Options
 
     #endregion

Osu.Stubs/Helpers/DataStoreUpdater.cs

@@ -0,0 +1,38 @@
+using JetBrains.Annotations;
+using Osu.Utils.Lazy;
+using static System.Reflection.Emit.OpCodes;
+
+namespace Osu.Stubs.Helpers;
+
+/// <summary>
+///     Original: <c>osu.Helpers.DataStoreUpdater</c>
+/// </summary>
+[PublicAPI]
+public class DataStoreUpdater
+{
+    /// <summary>
+    ///     Original: <c>Save(bool final)</c>
+    /// </summary>
+    [Stub]
+    public static readonly LazyMethod<bool> Save = LazyMethod<bool>.ByPartialSignature(
+        "osu.Helpers.DataStoreUpdater::Save(bool)",
+        [
+            Ldc_I4_0,
+            Stloc_0,
+            Leave_S,
+            Ldarg_0,
+            Ldsfld,
+            Stfld,
+            Ldarg_0,
+            Ldc_I4_0,
+            Stfld,
+            Ldarg_0,
+            Ldfld,
+            Callvirt,
+            Pop,
+            Endfinally,
+            Ldloc_0,
+            Ret,
+        ]
+    );
+}