Initial refactoring of key binding logic

osu.Game/Input/KeyBindingStore.cs

@@ -0,0 +1,61 @@
+// Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using System;
+using System.Collections.Generic;
+using osu.Framework.Input.Bindings;
+using osu.Framework.Platform;
+using osu.Game.Database;
+using osu.Game.Input.Bindings;
+using SQLite.Net;
+
+namespace osu.Game.Input
+{
+    public class KeyBindingStore : DatabaseBackedStore
+    {
+        public KeyBindingStore(SQLiteConnection connection, Storage storage = null)
+            : base(connection, storage)
+        {
+        }
+
+        protected override int StoreVersion => 2;
+
+        protected override void PerformMigration(int currentVersion, int targetVersion)
+        {
+            base.PerformMigration(currentVersion, targetVersion);
+
+            while (currentVersion++ < targetVersion)
+            {
+                switch (currentVersion)
+                {
+                    case 1:
+                        // cannot migrate; breaking underlying changes.
+                        Reset();
+                        break;
+                }
+            }
+        }
+
+        protected override void Prepare(bool reset = false)
+        {
+            Connection.CreateTable<DatabasedKeyBinding>();
+        }
+
+        protected override Type[] ValidTypes => new[]
+        {
+            typeof(DatabasedKeyBinding)
+        };
+
+        public List<KeyBinding> GetProcessedList(IEnumerable<KeyBinding> defaults, int? rulesetId, int? variant)
+        {
+            //todo: cache and share reference
+            List<KeyBinding> bindings = new List<KeyBinding>(defaults);
+
+            // load from database if present.
+            foreach (var b in Query<DatabasedKeyBinding>(b => b.RulesetID == rulesetId && b.Variant == variant))
+                bindings.Add(b);
+
+            return bindings;
+        }
+    }
+}