Give ruleset settings a ruleset-specific config manager

osu.Game/Overlays/Settings/RulesetSettingsSubsection.cs

@@ -0,0 +1,36 @@
+// Copyright (c) 2007-2018 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using osu.Framework.Allocation;
+using osu.Game.Configuration;
+using osu.Game.Rulesets;
+
+namespace osu.Game.Overlays.Settings
+{
+    /// <summary>
+    /// A <see cref="SettingsSubsection"/> which provides subclasses with the <see cref="IRulesetConfigManager"/>
+    /// from the <see cref="Ruleset"/>'s <see cref="Ruleset.CreateConfig()"/>.
+    /// </summary>
+    public abstract class RulesetSettingsSubsection : SettingsSubsection
+    {
+        private readonly Ruleset ruleset;
+
+        protected RulesetSettingsSubsection(Ruleset ruleset)
+        {
+            this.ruleset = ruleset;
+        }
+
+        private DependencyContainer dependencies;
+
+        protected override IReadOnlyDependencyContainer CreateLocalDependencies(IReadOnlyDependencyContainer parent)
+        {
+            dependencies = new DependencyContainer(base.CreateLocalDependencies(parent));
+
+            var config = ruleset.CreateConfig(dependencies.Get<SettingsStore>());
+            if (config != null)
+                dependencies.Cache(config);
+
+            return dependencies;
+        }
+    }
+}