reversible migrations

CoreStore/Migrating/DataStack+Migration.swift

@@ -446,6 +446,18 @@ public extension DataStack {
     
     private func startMigrationForSQLiteStore(fileURL fileURL: NSURL, sourceModel: NSManagedObjectModel, destinationModel: NSManagedObjectModel, mappingModel: NSMappingModel) throws {
         
+        autoreleasepool {
+            
+            let journalUpdatingCoordinator = NSPersistentStoreCoordinator(managedObjectModel: sourceModel)
+            let store = try! journalUpdatingCoordinator.addPersistentStoreWithType(
+                NSSQLiteStoreType,
+                configuration: nil,
+                URL: fileURL,
+                options: [NSSQLitePragmasOption: ["journal_mode": "DELETE"]]
+            )
+            try! journalUpdatingCoordinator.removePersistentStore(store)
+        }
+        
         let migrationManager = NSMigrationManager(
             sourceModel: sourceModel,
             destinationModel: destinationModel
@@ -475,21 +487,18 @@ public extension DataStack {
             withIntermediateDirectories: true,
             attributes: nil
         )
+        
+        let temporaryFileURL = temporaryDirectoryURL.URLByAppendingPathComponent(fileURL.lastPathComponent!, isDirectory: false)
         do {
             
             try migrationManager.migrateStoreFromURL(
                 fileURL,
                 type: NSSQLiteStoreType,
-                options: [
+                options: nil,
-                    NSSQLitePragmasOption: ["WAL": "journal_mode"]
-                ],
                 withMappingModel: mappingModel,
-                toDestinationURL: temporaryDirectoryURL.URLByAppendingPathComponent(fileURL.lastPathComponent!, isDirectory: false),
+                toDestinationURL: temporaryFileURL,
                 destinationType: NSSQLiteStoreType,
-                destinationOptions: [
+                destinationOptions: nil
-                    NSSQLitePragmasOption: ["WAL": "journal_mode"],
-                    NSSQLiteManualVacuumOption: true
-                ]
             )
         }
         catch {
@@ -515,20 +524,19 @@ public extension DataStack {
         
         do {
             
-            let originalDirectoryURL = fileURL.URLByDeletingLastPathComponent!
+            try fileManager.replaceItemAtURL(
-            for temporaryFileURL in try fileManager.contentsOfDirectoryAtURL(temporaryDirectoryURL, includingPropertiesForKeys: nil, options: .SkipsSubdirectoryDescendants) {
+                fileURL,
+                withItemAtURL: temporaryFileURL,
+                backupItemName: nil,
+                options: [],
+                resultingItemURL: nil
+            )
             
-                try fileManager.replaceItemAtURL(
+            do {
-                    originalDirectoryURL.URLByAppendingPathComponent(
+                
-                        temporaryFileURL.lastPathComponent!,
+                try fileManager.removeItemAtPath(fileURL.path! + "-shm")
-                        isDirectory: false
-                    ),
-                    withItemAtURL: temporaryFileURL,
-                    backupItemName: nil,
-                    options: [],
-                    resultingItemURL: nil
-                )
             }
+            catch _ { }
         }
         catch {
             

CoreStore/Setting Up/DataStack.swift

@@ -199,7 +199,7 @@ public final class DataStack {
                     configuration: configuration,
                     URL: fileURL,
                     options: [
-                        NSSQLitePragmasOption: ["WAL": "journal_mode"],
+                        NSSQLitePragmasOption: ["journal_mode": "WAL"],
                         NSInferMappingModelAutomaticallyOption: true,
                         NSMigratePersistentStoresAutomaticallyOption: automigrating
                     ]
@@ -254,7 +254,7 @@ public final class DataStack {
                             configuration: configuration,
                             URL: fileURL,
                             options: [
-                                NSSQLitePragmasOption: ["WAL": "journal_mode"],
+                                NSSQLitePragmasOption: ["journal_mode": "WAL"],
                                 NSInferMappingModelAutomaticallyOption: true,
                                 NSMigratePersistentStoresAutomaticallyOption: automigrating
                             ]
@@ -376,4 +376,16 @@ public final class DataStack {
     private let storeMetadataUpdateQueue = GCDQueue.createConcurrent("com.coreStore.persistentStoreBarrierQueue")
     private var configurationStoreMapping = [String: NSPersistentStore]()
     private var entityConfigurationsMapping = [String: Set<String>]()
+    
+    deinit {
+        
+        for store in self.coordinator.persistentStores {
+            
+            do {
+                
+                try self.coordinator.removePersistentStore(store)
+            }
+            catch _ { }
+        }
+    }
 }

CoreStoreDemo/CoreStoreDemo.xcodeproj/project.pbxproj

@@ -11,6 +11,7 @@
 		B503FAE01AFDC71700F90881 /* ObjectObserverDemoViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = B503FADC1AFDC71700F90881 /* ObjectObserverDemoViewController.swift */; };
 		B503FAE11AFDC71700F90881 /* Palette.swift in Sources */ = {isa = PBXBuildFile; fileRef = B503FADD1AFDC71700F90881 /* Palette.swift */; };
 		B503FAE21AFDC71700F90881 /* PaletteTableViewCell.swift in Sources */ = {isa = PBXBuildFile; fileRef = B503FADE1AFDC71700F90881 /* PaletteTableViewCell.swift */; };
+		B50D67911B4BCFED00124277 /* OrganismV3ToV2.xcmappingmodel in Sources */ = {isa = PBXBuildFile; fileRef = B50D67901B4BCFED00124277 /* OrganismV3ToV2.xcmappingmodel */; };
 		B52977D91B120B80003D50A5 /* ObserversViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = B52977D81B120B80003D50A5 /* ObserversViewController.swift */; };
 		B52977DD1B120F3B003D50A5 /* TransactionsDemoViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = B52977DC1B120F3B003D50A5 /* TransactionsDemoViewController.swift */; };
 		B52977DF1B120F83003D50A5 /* MapKit.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = B52977DE1B120F83003D50A5 /* MapKit.framework */; };
@@ -96,6 +97,7 @@
 		B503FADC1AFDC71700F90881 /* ObjectObserverDemoViewController.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = ObjectObserverDemoViewController.swift; sourceTree = "<group>"; };
 		B503FADD1AFDC71700F90881 /* Palette.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = Palette.swift; sourceTree = "<group>"; };
 		B503FADE1AFDC71700F90881 /* PaletteTableViewCell.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = PaletteTableViewCell.swift; sourceTree = "<group>"; };
+		B50D67901B4BCFED00124277 /* OrganismV3ToV2.xcmappingmodel */ = {isa = PBXFileReference; lastKnownFileType = wrapper.xcmappingmodel; name = OrganismV3ToV2.xcmappingmodel; path = "CoreStoreDemo/MIgrations Demo/OrganismV3ToV2.xcmappingmodel"; sourceTree = SOURCE_ROOT; };
 		B52977D81B120B80003D50A5 /* ObserversViewController.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = ObserversViewController.swift; sourceTree = "<group>"; };
 		B52977DC1B120F3B003D50A5 /* TransactionsDemoViewController.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = TransactionsDemoViewController.swift; sourceTree = "<group>"; };
 		B52977DE1B120F83003D50A5 /* MapKit.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = MapKit.framework; path = System/Library/Frameworks/MapKit.framework; sourceTree = SDKROOT; };
@@ -265,6 +267,7 @@
 				B5EE258B1B36E40D0000406B /* MigrationsDemoViewController.swift */,
 				B5F45A601B4AE5A700831F2F /* OrganismV2ToV3.xcmappingmodel */,
 				B560070E1B3EC90F00A9A8F9 /* OrganismV2ToV3MigrationPolicy.swift */,
+				B50D67901B4BCFED00124277 /* OrganismV3ToV2.xcmappingmodel */,
 			);
 			path = "Migrations Demo";
 			sourceTree = "<group>";
@@ -394,6 +397,7 @@
 				B5F45A611B4AE5A700831F2F /* OrganismV2ToV3.xcmappingmodel in Sources */,
 				B503FAE11AFDC71700F90881 /* Palette.swift in Sources */,
 				B503FAE21AFDC71700F90881 /* PaletteTableViewCell.swift in Sources */,
+				B50D67911B4BCFED00124277 /* OrganismV3ToV2.xcmappingmodel in Sources */,
 				B560070F1B3EC90F00A9A8F9 /* OrganismV2ToV3MigrationPolicy.swift in Sources */,
 				B503FADF1AFDC71700F90881 /* ListObserverDemoViewController.swift in Sources */,
 				B54AAD4F1AF4D26E00848AE0 /* AppDelegate.swift in Sources */,

CoreStoreDemo/CoreStoreDemo/MIgrations Demo/MigrationsDemoViewController.swift

@@ -170,7 +170,7 @@ class MigrationsDemoViewController: UITableViewController {
                 let navigationItem = self.navigationItem
                 navigationItem.leftBarButtonItem?.enabled = enabled
                 navigationItem.rightBarButtonItem?.enabled = enabled
-                navigationItem.backBarButtonItem?.enabled = enabled
+                navigationItem.hidesBackButton = !enabled
                 
                 if let tableView = self.tableView {