Refactors DatabaseManager into NSPersistentStore subclass

Common/Collection View/GameCollectionViewDataSource.swift

@@ -64,7 +64,7 @@ class GameCollectionViewDataSource: NSObject
         
         fetchRequest.sortDescriptors = [NSSortDescriptor(key: Game.Attributes.type.rawValue, ascending: true), NSSortDescriptor(key: Game.Attributes.name.rawValue, ascending: true)]
         
-        self.fetchedResultsController = NSFetchedResultsController(fetchRequest: fetchRequest, managedObjectContext: DatabaseManager.sharedManager.managedObjectContext, sectionNameKeyPath: Game.Attributes.type.rawValue, cacheName: nil)
+        self.fetchedResultsController = NSFetchedResultsController(fetchRequest: fetchRequest, managedObjectContext: DatabaseManager.shared.viewContext, sectionNameKeyPath: Game.Attributes.type.rawValue, cacheName: nil)
         self.fetchedResultsController.delegate = previousDelegate
         
         self.update()

Common/Database/DatabaseManager.swift

@@ -6,114 +6,54 @@
 //  Copyright © 2015 Riley Testut. All rights reserved.
 //
 
+import Foundation
 import CoreData
 
 // Workspace
-import Roxas
 import DeltaCore
 
 // Pods
 import FileMD5Hash
 
-class DatabaseManager
+final class DatabaseManager: NSPersistentContainer
 {
-    static let sharedManager = DatabaseManager()
+    static let shared = DatabaseManager()
-    
-    let managedObjectContext: NSManagedObjectContext
-    
-    private let privateManagedObjectContext: NSManagedObjectContext
-    private let validationManagedObjectContext: NSManagedObjectContext
-    
-    // MARK: - Initialization -
-    /// Initialization
     
     private init()
     {
-        let modelURL = Bundle.main.url(forResource: "Model", withExtension: "momd")
+        guard
-        let managedObjectModel = NSManagedObjectModel(contentsOf: modelURL!)
+            let modelURL = Bundle(for: DatabaseManager.self).url(forResource: "Model", withExtension: "momd"),
-        let persistentStoreCoordinator = NSPersistentStoreCoordinator(managedObjectModel: managedObjectModel!)
+            let managedObjectModel = NSManagedObjectModel(contentsOf: modelURL)
+        else { fatalError("Core Data model cannot be found. Aborting.") }
         
-        self.privateManagedObjectContext = NSManagedObjectContext(concurrencyType: .privateQueueConcurrencyType)
+        super.init(name: "Delta", managedObjectModel: managedObjectModel)
-        self.privateManagedObjectContext.persistentStoreCoordinator = persistentStoreCoordinator
-        self.privateManagedObjectContext.mergePolicy = NSMergeByPropertyObjectTrumpMergePolicy
-        
-        self.managedObjectContext = NSManagedObjectContext(concurrencyType: .mainQueueConcurrencyType)
-        self.managedObjectContext.parent = self.privateManagedObjectContext
-        self.managedObjectContext.mergePolicy = NSMergeByPropertyObjectTrumpMergePolicy
-        
-        self.validationManagedObjectContext = NSManagedObjectContext(concurrencyType: .privateQueueConcurrencyType)
-        self.validationManagedObjectContext.parent = self.managedObjectContext
-        self.validationManagedObjectContext.mergePolicy = NSMergeByPropertyObjectTrumpMergePolicy
-
-        NotificationCenter.default.addObserver(self, selector: #selector(DatabaseManager.managedObjectContextWillSave(_:)), name: NSNotification.Name.NSManagedObjectContextWillSave, object: nil)
-        NotificationCenter.default.addObserver(self, selector: #selector(DatabaseManager.managedObjectContextDidSave(_:)), name: NSNotification.Name.NSManagedObjectContextDidSave, object: nil)
         
+        self.viewContext.automaticallyMergesChangesFromParent = true
     }
+}
 
-    func startWithCompletion(_ completionBlock: ((performingMigration: Bool) -> Void)?)
+//MARK: - Importing -
+/// Importing
+extension DatabaseManager
+{
+    func importGames(at urls: [URL], completion: (([String]) -> Void)?)
     {
-        DispatchQueue.global(qos: .userInitiated).async {
+        self.performBackgroundTask { (context) in
-            
-            let storeURL = DatabaseManager.databaseDirectoryURL.appendingPathComponent("Delta.sqlite")
-
-            let options = [NSMigratePersistentStoresAutomaticallyOption: true, NSInferMappingModelAutomaticallyOption: true]
-            
-            var performingMigration = false
-            
-            if
-                let sourceMetadata = try? NSPersistentStoreCoordinator.metadataForPersistentStore(ofType: NSSQLiteStoreType, at: storeURL, options: options),
-                let managedObjectModel = self.privateManagedObjectContext.persistentStoreCoordinator?.managedObjectModel
-            {
-                performingMigration = !managedObjectModel.isConfiguration(withName: nil, compatibleWithStoreMetadata: sourceMetadata)
-            }
-            
-            do
-            {
-                try self.privateManagedObjectContext.persistentStoreCoordinator?.addPersistentStore(ofType: NSSQLiteStoreType, configurationName: nil, at: storeURL, options: options)
-            }
-            catch let error as NSError
-            {
-                if error.code == NSMigrationMissingSourceModelError
-                {
-                    print("Migration failed. Try deleting \(storeURL)")
-                }
-                else
-                {
-                    print(error)
-                }
-                
-                abort()
-            }
-            
-            if let completionBlock = completionBlock
-            {
-                completionBlock(performingMigration: performingMigration)
-            }
-        }
-    }
-    
-    // MARK: - Importing -
-    /// Importing
-    
-    func importGamesAtURLs(_ URLs: [URL], withCompletion completion: (([String]) -> Void)?)
-    {
-        let managedObjectContext = self.backgroundManagedObjectContext()
-        managedObjectContext.perform() {
             
             var identifiers: [String] = []
             
-            for URL in URLs
+            for url in urls
             {
-                let identifier = FileHash.sha1HashOfFile(atPath: URL.path) as String
+                let identifier = FileHash.sha1HashOfFile(atPath: url.path) as String
                 
-                let filename = identifier + "." + URL.pathExtension
+                let filename = identifier + "." + url.pathExtension
                 
-                let game = Game.insertIntoManagedObjectContext(managedObjectContext)
+                let game = Game.insertIntoManagedObjectContext(context)
-                game.name = URL.deletingPathExtension().lastPathComponent ?? NSLocalizedString("Game", comment: "")
+                game.name = url.deletingPathExtension().lastPathComponent ?? NSLocalizedString("Game", comment: "")
                 game.identifier = identifier
                 game.filename = filename
                 
-                let gameCollection = GameCollection.gameSystemCollectionForPathExtension(URL.pathExtension, inManagedObjectContext: managedObjectContext)
+                let gameCollection = GameCollection.gameSystemCollectionForPathExtension(url.pathExtension, inManagedObjectContext: context)
                 game.type = GameType(rawValue: gameCollection.identifier)
                 game.gameCollections.insert(gameCollection)
                 
@@ -123,11 +63,11 @@ class DatabaseManager
                     
                     if FileManager.default.fileExists(atPath: destinationURL.path)
                     {
-                        try FileManager.default.removeItem(at: URL)
+                        try FileManager.default.removeItem(at: url)
                     }
                     else
                     {
-                        try FileManager.default.moveItem(at: URL, to: destinationURL)
+                        try FileManager.default.moveItem(at: url, to: destinationURL)
                     }
                     
                     identifiers.append(game.identifier)
@@ -141,9 +81,9 @@ class DatabaseManager
             
             do
             {
-                try managedObjectContext.save()
+                try context.save()
             }
-            catch let error as NSError
+            catch
             {
                 print("Failed to save import context:", error)
                 
@@ -154,27 +94,16 @@ class DatabaseManager
             {
                 completion(identifiers)
             }
-        }
-        
             
         }
-    
-    // MARK: - Background Contexts -
-    /// Background Contexts
-    
-    func backgroundManagedObjectContext() -> NSManagedObjectContext
-    {
-        let managedObjectContext = NSManagedObjectContext(concurrencyType: .privateQueueConcurrencyType)
-        managedObjectContext.parent = self.validationManagedObjectContext
-        managedObjectContext.mergePolicy = NSMergeByPropertyObjectTrumpMergePolicy
-        
-        return managedObjectContext
     }
 }
 
+//MARK: - File URLs -
+/// File URLs
 extension DatabaseManager
 {
-    class var databaseDirectoryURL: URL
+    override class func defaultDirectoryURL() -> URL
     {
         let documentsDirectoryURL: URL
         
@@ -188,23 +117,23 @@ extension DatabaseManager
         }
         
         let databaseDirectoryURL = documentsDirectoryURL.appendingPathComponent("Database")
-        self.createDirectoryAtURLIfNeeded(databaseDirectoryURL)
+        self.createDirectory(at: databaseDirectoryURL)
         
         return databaseDirectoryURL
     }
 
     class var gamesDirectoryURL: URL
     {
-        let gamesDirectoryURL = DatabaseManager.databaseDirectoryURL.appendingPathComponent("Games")
+        let gamesDirectoryURL = DatabaseManager.defaultDirectoryURL().appendingPathComponent("Games")
-        self.createDirectoryAtURLIfNeeded(gamesDirectoryURL)
+        self.createDirectory(at: gamesDirectoryURL)
         
         return gamesDirectoryURL
     }
     
     class var saveStatesDirectoryURL: URL
     {
-        let saveStatesDirectoryURL = DatabaseManager.databaseDirectoryURL.appendingPathComponent("Save States")
+        let saveStatesDirectoryURL = DatabaseManager.defaultDirectoryURL().appendingPathComponent("Save States")
-        self.createDirectoryAtURLIfNeeded(saveStatesDirectoryURL)
+        self.createDirectory(at: saveStatesDirectoryURL)
         
         return saveStatesDirectoryURL
     }
@@ -212,141 +141,20 @@ extension DatabaseManager
     class func saveStatesDirectoryURLForGame(_ game: Game) -> URL
     {
         let gameDirectoryURL = DatabaseManager.saveStatesDirectoryURL.appendingPathComponent(game.identifier)
-        self.createDirectoryAtURLIfNeeded(gameDirectoryURL)
+        self.createDirectory(at: gameDirectoryURL)
         
         return gameDirectoryURL
     }
 }
 
+//MARK: - Private -
 private extension DatabaseManager
 {
-    // MARK: - Saving -
+    class func createDirectory(at url: URL)
-    
-    func save()
-    {
-        let backgroundTaskIdentifier = RSTBeginBackgroundTask("Save Database Task")
-        
-        self.validationManagedObjectContext.performAndWait {
-            
-            do
-            {
-                try self.validationManagedObjectContext.save()
-            }
-            catch let error as NSError
-            {
-                print("Failed to save validation context:", error)
-            }
-            
-            
-            // Update main managed object context
-            self.managedObjectContext.performAndWait() {
-                
-                do
-                {
-                    try self.managedObjectContext.save()
-                }
-                catch let error as NSError
-                {
-                    print("Failed to save main context:", error)
-                }
-                
-                
-                // Save to disk
-                self.privateManagedObjectContext.perform() {
-                    
-                    do
-                    {
-                        try self.privateManagedObjectContext.save()
-                    }
-                    catch let error as NSError
-                    {
-                        print("Failed to save private context to disk:", error)
-                    }
-                    
-                    RSTEndBackgroundTask(backgroundTaskIdentifier)
-                    
-                }
-                
-            }
-            
-        }
-    }
-    
-    // MARK: - Validation -
-    
-    func validateManagedObjectContextSave(_ managedObjectContext: NSManagedObjectContext)
-    {
-        // Remove deleted files from disk
-        for object in managedObjectContext.deletedObjects
-        {
-            var fileURLs = Set<URL>()
-            
-            let temporaryObject = self.validationManagedObjectContext.object(with: object.objectID)
-            switch temporaryObject
-            {
-            case let game as Game:
-                fileURLs.insert(game.fileURL as URL)
-                
-            case let saveState as SaveState:
-                fileURLs.insert(saveState.fileURL as URL)
-                fileURLs.insert(saveState.imageFileURL as URL)
-                
-            default: break
-            }
-            
-            for URL in fileURLs
     {
         do
         {
-                    try FileManager.default.removeItem(at: URL)
+            try FileManager.default.createDirectory(at: url, withIntermediateDirectories: true, attributes: nil)
-                }
-                catch let error as NSError
-                {
-                    print(error)
-                }
-            }
-        }
-        
-        // Remove empty collections
-        let collections = GameCollection.instancesWithPredicate(NSPredicate(format: "%K.@count == 0", GameCollection.Attributes.games.rawValue), inManagedObjectContext: self.validationManagedObjectContext, type: GameCollection.self)
-        
-        for collection in collections
-        {
-            self.validationManagedObjectContext.delete(collection)
-        }
-    }
-    
-    // MARK: - Notifications -
-    
-    @objc func managedObjectContextWillSave(_ notification: Notification)
-    {
-        guard
-            let managedObjectContext = notification.object as? NSManagedObjectContext,
-            managedObjectContext.parent == self.validationManagedObjectContext
-        else { return }
-        
-        self.validationManagedObjectContext.performAndWait {
-            self.validateManagedObjectContextSave(managedObjectContext)
-        }
-    }
-    
-    @objc func managedObjectContextDidSave(_ notification: Notification)
-    {
-        guard
-            let managedObjectContext = notification.object as? NSManagedObjectContext,
-            managedObjectContext.parent == self.validationManagedObjectContext
-        else { return }
-        
-        self.save()
-    }
-    
-    // MARK: - File Management -
-    
-    class func createDirectoryAtURLIfNeeded(_ URL: Foundation.URL)
-    {
-        do
-        {
-            try FileManager.default.createDirectory(at: URL, withIntermediateDirectories: true, attributes: nil)
         }
         catch
         {

Common/Database/Model/Game.swift

@@ -62,6 +62,39 @@ class Game: NSManagedObject, GameProtocol
     }
 }
 
+extension Game
+{
+    override public func prepareForDeletion()
+    {
+        super.prepareForDeletion()
+        
+        guard FileManager.default.fileExists(atPath: self.fileURL.path) else { return }
+        
+        do
+        {
+            try FileManager.default.removeItem(at: self.fileURL)
+        }
+        catch
+        {
+            print(error)
+        }
+        
+        if let managedObjectContext = self.managedObjectContext
+        {
+            for collection in self.gameCollections where collection.games.count == 1
+            {
+                // Once this game is deleted, collection will have 0 games, so we should delete it
+                managedObjectContext.delete(collection)
+            }
+            
+            if managedObjectContext.hasChanges
+            {
+                managedObjectContext.saveWithErrorLogging()
+            }
+        }
+    }
+}
+
 extension Game
 {
     class func supportedTypeIdentifiers() -> Set<String>

Common/Database/Model/SaveState.swift

@@ -70,6 +70,25 @@ class SaveState: NSManagedObject, SaveStateProtocol
     }
 }
 
+extension SaveState
+{
+    override public func prepareForDeletion()
+    {
+        super.prepareForDeletion()
+        
+        guard FileManager.default.fileExists(atPath: self.fileURL.path) else { return }
+        
+        do
+        {
+            try FileManager.default.removeItem(at: self.fileURL)
+        }
+        catch
+        {
+            print(error)
+        }
+    }
+}
+
 extension SaveState
 {
     @NSManaged private var primitiveFilename: String

Common/Importing/GamePickerController.swift

@@ -53,15 +53,14 @@ class GamePickerController: NSObject
         
         let importAction = UIAlertAction(title: NSLocalizedString("Import", comment: ""), style: .default) { action in
             
-            let documentsDirectoryURL = DatabaseManager.databaseDirectoryURL.deletingLastPathComponent()
+            let documentsDirectoryURL = DatabaseManager.defaultDirectoryURL().deletingLastPathComponent()
             
             do
             {
                 let contents = try FileManager.default.contentsOfDirectory(at: documentsDirectoryURL, includingPropertiesForKeys: nil, options: .skipsHiddenFiles)
                 
-                let managedObjectContext = DatabaseManager.sharedManager.backgroundManagedObjectContext()
+                DatabaseManager.shared.performBackgroundTask { (context) in
-                managedObjectContext.perform() {
+                    let gameURLs = contents.filter({ GameCollection.gameSystemCollectionForPathExtension($0.pathExtension, inManagedObjectContext: context).identifier != GameType.delta.rawValue })
-                    let gameURLs = contents.filter({ GameCollection.gameSystemCollectionForPathExtension($0.pathExtension, inManagedObjectContext: managedObjectContext).identifier != GameType.delta.rawValue })
                     self.importGamesAtURLs(gameURLs)
                 }
                 
@@ -87,12 +86,12 @@ class GamePickerController: NSObject
     
     private func importGamesAtURLs(_ URLs: [URL])
     {
-        DatabaseManager.sharedManager.importGamesAtURLs(URLs) { identifiers in
+        DatabaseManager.shared.importGames(at: URLs) { identifiers in
             
-            DatabaseManager.sharedManager.managedObjectContext.perform() {
+            DatabaseManager.shared.viewContext.perform() {
                 
                 let predicate = NSPredicate(format: "%K IN (%@)", Game.Attributes.identifier.rawValue, identifiers)
-                let games = Game.instancesWithPredicate(predicate, inManagedObjectContext: DatabaseManager.sharedManager.managedObjectContext, type: Game.self)
+                let games = Game.instancesWithPredicate(predicate, inManagedObjectContext: DatabaseManager.shared.viewContext, type: Game.self)
                                 
                 self.delegate?.gamePickerController(self, didImportGames: games)
                 

Delta.xcodeproj/project.pbxproj

@@ -35,7 +35,6 @@
 		BF65E8631CEE5C6A00CD3247 /* Cheat.swift in Sources */ = {isa = PBXBuildFile; fileRef = BF65E8621CEE5C6A00CD3247 /* Cheat.swift */; };
 		BF70798C1B6B464B0019077C /* ZipZap.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = BF70798B1B6B464B0019077C /* ZipZap.framework */; };
 		BF70798D1B6B464B0019077C /* ZipZap.framework in Embed Frameworks */ = {isa = PBXBuildFile; fileRef = BF70798B1B6B464B0019077C /* ZipZap.framework */; settings = {ATTRIBUTES = (CodeSignOnCopy, RemoveHeadersOnCopy, ); }; };
-		BF762E9E1BC19D31002C8866 /* DatabaseManager.swift in Sources */ = {isa = PBXBuildFile; fileRef = BF762E9D1BC19D31002C8866 /* DatabaseManager.swift */; };
 		BF762EAB1BC1B076002C8866 /* NSManagedObject+Conveniences.swift in Sources */ = {isa = PBXBuildFile; fileRef = BF762EAA1BC1B076002C8866 /* NSManagedObject+Conveniences.swift */; };
 		BF797A2D1C2D339F00F1A000 /* UILabel+FontSize.swift in Sources */ = {isa = PBXBuildFile; fileRef = BF797A2C1C2D339F00F1A000 /* UILabel+FontSize.swift */; };
 		BF7AE8081C2E858400B1B5BC /* PauseMenuViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = BF7AE8041C2E858400B1B5BC /* PauseMenuViewController.swift */; };
@@ -51,6 +50,7 @@
 		BFAA1FED1B8AA4FA00495943 /* Settings.swift in Sources */ = {isa = PBXBuildFile; fileRef = BFAA1FEC1B8AA4FA00495943 /* Settings.swift */; };
 		BFAA1FF41B8AD7F900495943 /* ControllersSettingsViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = BFAA1FF31B8AD7F900495943 /* ControllersSettingsViewController.swift */; };
 		BFB141181BE46934004FBF46 /* GameCollectionViewDataSource.swift in Sources */ = {isa = PBXBuildFile; fileRef = BFB141171BE46934004FBF46 /* GameCollectionViewDataSource.swift */; };
+		BFBAA86A1D5A483900A29C1B /* DatabaseManager.swift in Sources */ = {isa = PBXBuildFile; fileRef = BFBAA8691D5A483900A29C1B /* DatabaseManager.swift */; };
 		BFC2731A1BE6152200D22B05 /* GameCollection.swift in Sources */ = {isa = PBXBuildFile; fileRef = BFC273171BE6152200D22B05 /* GameCollection.swift */; };
 		BFC9B7391CEFCD34008629BB /* CheatsViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = BFC9B7381CEFCD34008629BB /* CheatsViewController.swift */; };
 		BFCEA67E1D56FF640061A534 /* UIViewControllerContextTransitioning+Conveniences.swift in Sources */ = {isa = PBXBuildFile; fileRef = BFCEA67D1D56FF640061A534 /* UIViewControllerContextTransitioning+Conveniences.swift */; };
@@ -126,7 +126,6 @@
 		BF65E8621CEE5C6A00CD3247 /* Cheat.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = Cheat.swift; sourceTree = "<group>"; };
 		BF6BB2451BB73FE800CCF94A /* Assets.xcassets */ = {isa = PBXFileReference; lastKnownFileType = folder.assetcatalog; path = Assets.xcassets; sourceTree = "<group>"; };
 		BF70798B1B6B464B0019077C /* ZipZap.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; path = ZipZap.framework; sourceTree = BUILT_PRODUCTS_DIR; };
-		BF762E9D1BC19D31002C8866 /* DatabaseManager.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = DatabaseManager.swift; sourceTree = "<group>"; };
 		BF762EAA1BC1B076002C8866 /* NSManagedObject+Conveniences.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = "NSManagedObject+Conveniences.swift"; sourceTree = "<group>"; };
 		BF797A2C1C2D339F00F1A000 /* UILabel+FontSize.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = "UILabel+FontSize.swift"; sourceTree = "<group>"; };
 		BF7AE8041C2E858400B1B5BC /* PauseMenuViewController.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; name = PauseMenuViewController.swift; path = "Pause Menu/PauseMenuViewController.swift"; sourceTree = "<group>"; };
@@ -138,6 +137,7 @@
 		BFAA1FEC1B8AA4FA00495943 /* Settings.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = Settings.swift; sourceTree = "<group>"; };
 		BFAA1FF31B8AD7F900495943 /* ControllersSettingsViewController.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = ControllersSettingsViewController.swift; sourceTree = "<group>"; };
 		BFB141171BE46934004FBF46 /* GameCollectionViewDataSource.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; name = GameCollectionViewDataSource.swift; path = "Collection View/GameCollectionViewDataSource.swift"; sourceTree = "<group>"; };
+		BFBAA8691D5A483900A29C1B /* DatabaseManager.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = DatabaseManager.swift; sourceTree = "<group>"; };
 		BFC134E01AAD82460087AD7B /* SNESDeltaCore.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; path = SNESDeltaCore.framework; sourceTree = BUILT_PRODUCTS_DIR; };
 		BFC273171BE6152200D22B05 /* GameCollection.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = GameCollection.swift; sourceTree = "<group>"; };
 		BFC9B7381CEFCD34008629BB /* CheatsViewController.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; name = CheatsViewController.swift; path = "Pause Menu/Cheats/CheatsViewController.swift"; sourceTree = "<group>"; };
@@ -229,7 +229,7 @@
 		BF4566E41BC0902E007BFA1A /* Database */ = {
 			isa = PBXGroup;
 			children = (
-				BF762E9D1BC19D31002C8866 /* DatabaseManager.swift */,
+				BFBAA8691D5A483900A29C1B /* DatabaseManager.swift */,
 				BF4566E51BC09033007BFA1A /* Model */,
 			);
 			path = Database;
@@ -583,6 +583,7 @@
 				BFAA1FF41B8AD7F900495943 /* ControllersSettingsViewController.swift in Sources */,
 				BF353FF91C5D870B00C1184C /* PauseItem.swift in Sources */,
 				BF27CC971BCC890700A20D89 /* GamesCollectionViewController.swift in Sources */,
+				BFBAA86A1D5A483900A29C1B /* DatabaseManager.swift in Sources */,
 				BFFA71DD1AAC406100EE9DD1 /* AppDelegate.swift in Sources */,
 				BF7AE81E1C2E984300B1B5BC /* GridCollectionViewCell.swift in Sources */,
 				BF34FA111CF1899D006624C7 /* CheatTextView.swift in Sources */,
@@ -600,7 +601,6 @@
 				BF02BD001D361BD1000892F2 /* NSFetchedResultsController+Conveniences.m in Sources */,
 				BFFC464C1D5998D600AF2CC6 /* CheatTableViewCell.swift in Sources */,
 				BF7AE80A1C2E8C7600B1B5BC /* UIColor+Delta.swift in Sources */,
-				BF762E9E1BC19D31002C8866 /* DatabaseManager.swift in Sources */,
 				BF090CF41B490D8300DCAB45 /* UIDevice+Vibration.m in Sources */,
 				BF797A2D1C2D339F00F1A000 /* UILabel+FontSize.swift in Sources */,
 				BFD097211D3A01B8005A44C2 /* SaveStatesViewController.swift in Sources */,

Delta/AppDelegate.swift

@@ -26,14 +26,9 @@ class AppDelegate: UIResponder, UIApplicationDelegate
         
         // Database
         
-        let semaphore = DispatchSemaphore(value: 0)
+        DatabaseManager.shared.loadPersistentStores { (description, error) in
-        
-        DatabaseManager.sharedManager.startWithCompletion { performingMigration in
-            semaphore.signal()
         }
         
-        semaphore.wait()
-        
         // Controllers
         ExternalControllerManager.shared.startMonitoringExternalControllers()
                 

Delta/Emulation/GameViewController.swift

@@ -453,7 +453,7 @@ extension GameViewController: CheatsViewControllerDelegate
             self.pauseEmulation()
         }
         
-        let backgroundContext = DatabaseManager.sharedManager.backgroundManagedObjectContext()
+        let backgroundContext = DatabaseManager.shared.newBackgroundContext()
         backgroundContext.performAndWait {
             
             let predicate = NSPredicate(format: "%K == %@", Cheat.Attributes.game.rawValue, game)

Delta/Game Selection/GamesViewController.swift

@@ -45,7 +45,7 @@ class GamesViewController: UIViewController
         let fetchRequest = GameCollection.rst_fetchRequest()
         fetchRequest.sortDescriptors = [NSSortDescriptor(key: GameCollection.Attributes.index.rawValue, ascending: true)]
                 
-        self.fetchedResultsController = NSFetchedResultsController(fetchRequest: fetchRequest, managedObjectContext: DatabaseManager.sharedManager.managedObjectContext, sectionNameKeyPath: nil, cacheName: nil)
+        self.fetchedResultsController = NSFetchedResultsController(fetchRequest: fetchRequest, managedObjectContext: DatabaseManager.shared.viewContext, sectionNameKeyPath: nil, cacheName: nil)
         
         super.init(coder: aDecoder)
         

Delta/Pause Menu/Cheats/CheatsViewController.swift

@@ -97,7 +97,7 @@ private extension CheatsViewController
         fetchRequest.predicate = NSPredicate(format: "%K == %@", Cheat.Attributes.game.rawValue, self.game)
         fetchRequest.sortDescriptors = [NSSortDescriptor(key: Cheat.Attributes.name.rawValue, ascending: true)]
         
-        self.fetchedResultsController = NSFetchedResultsController(fetchRequest: fetchRequest, managedObjectContext: DatabaseManager.sharedManager.managedObjectContext, sectionNameKeyPath: nil, cacheName: nil)
+        self.fetchedResultsController = NSFetchedResultsController(fetchRequest: fetchRequest, managedObjectContext: DatabaseManager.shared.viewContext, sectionNameKeyPath: nil, cacheName: nil)
         self.fetchedResultsController.delegate = self
     }
     
@@ -130,11 +130,10 @@ private extension CheatsViewController
     {
         self.delegate?.cheatsViewController(self, deactivateCheat: cheat)
         
-        let backgroundContext = DatabaseManager.sharedManager.backgroundManagedObjectContext()
+        DatabaseManager.shared.performBackgroundTask { (context) in
-        backgroundContext.perform {
+            let temporaryCheat = context.object(with: cheat.objectID)
-            let temporaryCheat = backgroundContext.object(with: cheat.objectID)
+            context.delete(temporaryCheat)
-            backgroundContext.delete(temporaryCheat)
+            context.saveWithErrorLogging()
-            backgroundContext.saveWithErrorLogging()
         }
     }
 }
@@ -193,7 +192,7 @@ extension CheatsViewController
     {
         let cheat = self.fetchedResultsController.object(at: indexPath) as! Cheat
         
-        let backgroundContext = DatabaseManager.sharedManager.backgroundManagedObjectContext()
+        let backgroundContext = DatabaseManager.shared.newBackgroundContext()
         backgroundContext.performAndWait {
             let temporaryCheat = backgroundContext.object(with: cheat.objectID) as! Cheat
             temporaryCheat.enabled = !temporaryCheat.enabled

Delta/Pause Menu/Cheats/EditCheatViewController.swift

@@ -49,7 +49,7 @@ class EditCheatViewController: UITableViewController
     }
     
     private var mutableCheat: Cheat!
-    private var managedObjectContext = DatabaseManager.sharedManager.backgroundManagedObjectContext()
+    private var managedObjectContext = DatabaseManager.shared.newBackgroundContext()
     
     @IBOutlet private var nameTextField: UITextField!
     @IBOutlet private var typeSegmentedControl: UISegmentedControl!
@@ -76,11 +76,10 @@ class EditCheatViewController: UITableViewController
         let deleteAction = UIPreviewAction(title: NSLocalizedString("Delete", comment: ""), style: .destructive) { [unowned self] (action, viewController) in
             self.delegate?.editCheatViewController(self, deactivateCheat: cheat)
             
-            let backgroundContext = DatabaseManager.sharedManager.backgroundManagedObjectContext()
+            DatabaseManager.shared.performBackgroundTask { (context) in
-            backgroundContext.perform {
+                let temporaryCheat = context.object(with: cheat.objectID)
-                let temporaryCheat = backgroundContext.object(with: cheat.objectID)
+                context.delete(temporaryCheat)
-                backgroundContext.delete(temporaryCheat)
+                context.saveWithErrorLogging()
-                backgroundContext.saveWithErrorLogging()
             }
         }
         

Delta/Pause Menu/Save States/SaveStatesViewController.swift

@@ -168,7 +168,7 @@ private extension SaveStatesViewController
         fetchRequest.predicate = NSPredicate(format: "%K == %@", SaveState.Attributes.game.rawValue, self.game)
         fetchRequest.sortDescriptors = [NSSortDescriptor(key: SaveState.Attributes.type.rawValue, ascending: true), NSSortDescriptor(key: SaveState.Attributes.creationDate.rawValue, ascending: true)]
         
-        self.fetchedResultsController = NSFetchedResultsController(fetchRequest: fetchRequest, managedObjectContext: DatabaseManager.sharedManager.managedObjectContext, sectionNameKeyPath: SaveState.Attributes.type.rawValue, cacheName: nil)
+        self.fetchedResultsController = NSFetchedResultsController(fetchRequest: fetchRequest, managedObjectContext: DatabaseManager.shared.viewContext, sectionNameKeyPath: SaveState.Attributes.type.rawValue, cacheName: nil)
         self.fetchedResultsController.delegate = self
     }
     
@@ -275,7 +275,7 @@ private extension SaveStatesViewController
     {
         var saveState: SaveState!
         
-        let backgroundContext = DatabaseManager.sharedManager.backgroundManagedObjectContext()
+        let backgroundContext = DatabaseManager.shared.newBackgroundContext()
         backgroundContext.performAndWait {
             
             let game = backgroundContext.object(with: self.game.objectID) as! Game
@@ -324,14 +324,12 @@ private extension SaveStatesViewController
         let confirmationAlertController = UIAlertController(title: NSLocalizedString("Delete Save State?", comment: ""), message: NSLocalizedString("Are you sure you want to delete this save state? This cannot be undone.", comment: ""), preferredStyle: .alert)
         confirmationAlertController.addAction(UIAlertAction(title: NSLocalizedString("Delete", comment: ""), style: .default, handler: { action in
             
-            let backgroundContext = DatabaseManager.sharedManager.backgroundManagedObjectContext()
+            DatabaseManager.shared.performBackgroundTask { (context) in
-            backgroundContext.perform {
+                let temporarySaveState = context.object(with: saveState.objectID)
-                let temporarySaveState = backgroundContext.object(with: saveState.objectID)
+                context.delete(temporarySaveState)
-                backgroundContext.delete(temporarySaveState)
+                context.saveWithErrorLogging()
-                backgroundContext.saveWithErrorLogging()
             }
             
-            
         }))
         confirmationAlertController.addAction(UIAlertAction(title: NSLocalizedString("Cancel", comment: ""), style: .cancel, handler: nil))
         
@@ -370,13 +368,11 @@ private extension SaveStatesViewController
             text = nil
         }
         
-        let backgroundContext = DatabaseManager.sharedManager.backgroundManagedObjectContext()
+        DatabaseManager.shared.performBackgroundTask { (context) in
-        backgroundContext.perform {
+            let saveState = context.object(with: selectedSaveState.objectID) as! SaveState
-            
-            let saveState = backgroundContext.object(with: selectedSaveState.objectID) as! SaveState
             saveState.name = text
             
-            backgroundContext.saveWithErrorLogging()
+            context.saveWithErrorLogging()
         }
         
         self.selectedSaveState = nil
@@ -388,14 +384,12 @@ private extension SaveStatesViewController
         alertController.addAction(UIAlertAction(title: NSLocalizedString("Cancel", comment: ""), style: .cancel, handler: nil))
         alertController.addAction(UIAlertAction(title: NSLocalizedString("Change", comment: ""), style: .default, handler: { (action) in
             
-            let backgroundContext = DatabaseManager.sharedManager.backgroundManagedObjectContext()
+            DatabaseManager.shared.performBackgroundTask { (context) in
-            backgroundContext.perform {
+                let game = context.object(with: self.game.objectID) as! Game
-                
-                let game = backgroundContext.object(with: self.game.objectID) as! Game
                 
                 if let saveState = saveState
                 {
-                    let previewSaveState = backgroundContext.object(with: saveState.objectID) as! SaveState
+                    let previewSaveState = context.object(with: saveState.objectID) as! SaveState
                     game.previewSaveState = previewSaveState
                 }
                 else
@@ -403,9 +397,8 @@ private extension SaveStatesViewController
                     game.previewSaveState = nil
                 }
                 
-                backgroundContext.saveWithErrorLogging()
+                context.saveWithErrorLogging()
             }
-            
         }))
         
         self.present(alertController, animated: true, completion: nil)
@@ -413,7 +406,7 @@ private extension SaveStatesViewController
     
     func lockSaveState(_ saveState: SaveState)
     {
-        let backgroundContext = DatabaseManager.sharedManager.backgroundManagedObjectContext()
+        let backgroundContext = DatabaseManager.shared.newBackgroundContext()
         backgroundContext.performAndWait() {
             let temporarySaveState = backgroundContext.object(with: saveState.objectID) as! SaveState
             temporarySaveState.type = .locked
@@ -423,7 +416,7 @@ private extension SaveStatesViewController
     
     func unlockSaveState(_ saveState: SaveState)
     {
-        let backgroundContext = DatabaseManager.sharedManager.backgroundManagedObjectContext()
+        let backgroundContext = DatabaseManager.shared.newBackgroundContext()
         backgroundContext.performAndWait() {
             let temporarySaveState = backgroundContext.object(with: saveState.objectID) as! SaveState
             temporarySaveState.type = .general
@@ -692,7 +685,7 @@ extension SaveStatesViewController
             {
             case .auto: break
             case .general:
-                let backgroundContext = DatabaseManager.sharedManager.backgroundManagedObjectContext()
+                let backgroundContext = DatabaseManager.shared.newBackgroundContext()
                 backgroundContext.performAndWait() {
                     let temporarySaveState = backgroundContext.object(with: saveState.objectID) as! SaveState
                     self.updateSaveState(temporarySaveState)