Remove SingletonContextFactory

It is dangerous to use this as it doesn't correctly handle contexts and can cause issues that will never actually arise in normal execution.

osu.Game.Tests/Visual/TestCasePlaySongSelect.cs

@@ -62,7 +62,12 @@ private void load()
             var storage = new TestStorage(@"TestCasePlaySongSelect");
 
             // this is by no means clean. should be replacing inside of OsuGameBase somehow.
-            IDatabaseContextFactory factory = new SingletonContextFactory(new OsuDbContext());
+            DatabaseContextFactory factory = new DatabaseContextFactory(storage);
+
+            factory.ResetDatabase();
+
+            using (var usage = factory.Get())
+                usage.Migrate();
 
             Dependencies.Cache(rulesets = new RulesetStore(factory));
             Dependencies.Cache(manager = new BeatmapManager(storage, factory, rulesets, null, null)

osu.Game/Database/DatabaseContextFactory.cs

@@ -11,7 +11,7 @@ namespace osu.Game.Database
 {
     public class DatabaseContextFactory : IDatabaseContextFactory
     {
-        private readonly GameHost host;
+        private readonly Storage storage;
 
         private const string database_name = @"client";
 
@@ -26,9 +26,9 @@ public class DatabaseContextFactory : IDatabaseContextFactory
 
         private IDbContextTransaction currentWriteTransaction;
 
-        public DatabaseContextFactory(GameHost host)
+        public DatabaseContextFactory(Storage storage)
         {
-            this.host = host;
+            this.storage = storage;
             recycleThreadContexts();
         }
 
@@ -117,7 +117,7 @@ private void usageCompleted(DatabaseWriteUsage usage)
 
         private void recycleThreadContexts() => threadContexts = new ThreadLocal<OsuDbContext>(CreateContext);
 
-        protected virtual OsuDbContext CreateContext() => new OsuDbContext(host.Storage.GetDatabaseConnectionString(database_name))
+        protected virtual OsuDbContext CreateContext() => new OsuDbContext(storage.GetDatabaseConnectionString(database_name))
         {
             Database = { AutoTransactionsEnabled = false }
         };
@@ -129,7 +129,7 @@ public void ResetDatabase()
                 recycleThreadContexts();
                 GC.Collect();
                 GC.WaitForPendingFinalizers();
-                host.Storage.DeleteDatabase(database_name);
+                storage.DeleteDatabase(database_name);
             }
         }
     }

osu.Game/Database/SingletonContextFactory.cs

@@ -1,19 +0,0 @@
-// Copyright (c) 2007-2018 ppy Pty Ltd <contact@ppy.sh>.
-// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
-
-namespace osu.Game.Database
-{
-    public class SingletonContextFactory : IDatabaseContextFactory
-    {
-        private readonly OsuDbContext context;
-
-        public SingletonContextFactory(OsuDbContext context)
-        {
-            this.context = context;
-        }
-
-        public OsuDbContext Get() => context;
-
-        public DatabaseWriteUsage GetForWrite(bool withTransaction = true) => new DatabaseWriteUsage(context, null) { IsTransactionLeader = true };
-    }
-}

osu.Game/OsuGameBase.cs

@@ -107,7 +107,7 @@ private void load()
         {
             Resources.AddStore(new DllResourceStore(@"osu.Game.Resources.dll"));
 
-            dependencies.Cache(contextFactory = new DatabaseContextFactory(Host));
+            dependencies.Cache(contextFactory = new DatabaseContextFactory(Host.Storage));
 
             dependencies.Cache(new LargeTextureStore(new RawTextureLoaderStore(new NamespacedResourceStore<byte[]>(Resources, @"Textures"))));
 

osu.Game/Tests/Platform/TestStorage.cs

@@ -7,13 +7,11 @@ namespace osu.Game.Tests.Platform
 {
     public class TestStorage : DesktopStorage
     {
-        public TestStorage(string baseName) : base(baseName, null)
+        public TestStorage(string baseName)
+            : base(baseName, null)
         {
         }
 
-        public override string GetDatabaseConnectionString(string name)
-        {
-            return "DataSource=:memory:";
-        }
+        public override string GetDatabaseConnectionString(string name) => "Data Source=" + GetUsablePathFor($"{(object)name}.db", true);
     }
 }