WIP

CoreStore.xcodeproj/project.pbxproj

@@ -398,6 +398,10 @@
 		B59FA0B11CCBACA7007C9BCA /* ICloudStore.swift in Sources */ = {isa = PBXBuildFile; fileRef = B59FA0AD1CCBAC95007C9BCA /* ICloudStore.swift */; };
 		B59FA0B21CCBACA8007C9BCA /* ICloudStore.swift in Sources */ = {isa = PBXBuildFile; fileRef = B59FA0AD1CCBAC95007C9BCA /* ICloudStore.swift */; };
 		B5A261211B64BFDB006EB6D3 /* MigrationType.swift in Sources */ = {isa = PBXBuildFile; fileRef = B5A261201B64BFDB006EB6D3 /* MigrationType.swift */; };
+		B5A27F861E857C5300203C3E /* TransactionResult.swift in Sources */ = {isa = PBXBuildFile; fileRef = B5A27F851E857C5300203C3E /* TransactionResult.swift */; };
+		B5A27F871E857C5300203C3E /* TransactionResult.swift in Sources */ = {isa = PBXBuildFile; fileRef = B5A27F851E857C5300203C3E /* TransactionResult.swift */; };
+		B5A27F881E857C5300203C3E /* TransactionResult.swift in Sources */ = {isa = PBXBuildFile; fileRef = B5A27F851E857C5300203C3E /* TransactionResult.swift */; };
+		B5A27F891E857C5300203C3E /* TransactionResult.swift in Sources */ = {isa = PBXBuildFile; fileRef = B5A27F851E857C5300203C3E /* TransactionResult.swift */; };
 		B5A5F2661CAEC50F004AB9AF /* CSSelect.swift in Sources */ = {isa = PBXBuildFile; fileRef = B5A5F2651CAEC50F004AB9AF /* CSSelect.swift */; };
 		B5A5F2681CAEC50F004AB9AF /* CSSelect.swift in Sources */ = {isa = PBXBuildFile; fileRef = B5A5F2651CAEC50F004AB9AF /* CSSelect.swift */; };
 		B5A5F2691CAEC50F004AB9AF /* CSSelect.swift in Sources */ = {isa = PBXBuildFile; fileRef = B5A5F2651CAEC50F004AB9AF /* CSSelect.swift */; };
@@ -685,6 +689,7 @@
 		B59AFF401C6593E400C0ABE2 /* NSPersistentStoreCoordinator+Setup.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = "NSPersistentStoreCoordinator+Setup.swift"; sourceTree = "<group>"; };
 		B59FA0AD1CCBAC95007C9BCA /* ICloudStore.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = ICloudStore.swift; sourceTree = "<group>"; };
 		B5A261201B64BFDB006EB6D3 /* MigrationType.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = MigrationType.swift; sourceTree = "<group>"; };
+		B5A27F851E857C5300203C3E /* TransactionResult.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = TransactionResult.swift; sourceTree = "<group>"; };
 		B5A5F2651CAEC50F004AB9AF /* CSSelect.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = CSSelect.swift; sourceTree = "<group>"; };
 		B5AD60CD1C90141E00F2B2E8 /* Package.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = Package.swift; sourceTree = SOURCE_ROOT; };
 		B5AEFAB41C9962AE00AD137F /* CoreStoreBridge.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = CoreStoreBridge.swift; sourceTree = "<group>"; };
@@ -1160,6 +1165,7 @@
 				B5E84EEE1AFF846E0064E85B /* CoreStore+Transaction.swift */,
 				B50392F81C478FF3009900CA /* NSManagedObject+Transaction.swift */,
 				B5E84EF21AFF846E0064E85B /* SaveResult.swift */,
+				B5A27F851E857C5300203C3E /* TransactionResult.swift */,
 			);
 			path = Transactions;
 			sourceTree = "<group>";
@@ -1603,6 +1609,7 @@
 				B549F6731E56A92800FBAB2D /* CoreDataNativeType.swift in Sources */,
 				B509C7F41E54511B0061C547 /* ImportableAttributeType.swift in Sources */,
 				B5E84F0E1AFF847B0064E85B /* Tweak.swift in Sources */,
+				B5A27F861E857C5300203C3E /* TransactionResult.swift in Sources */,
 				B5E1B5931CAA0C15007FD580 /* CSObjectMonitor.swift in Sources */,
 				B5ECDC291CA81CC700C7F112 /* CSDataStack+Transaction.swift in Sources */,
 				B5E84F121AFF847B0064E85B /* OrderBy.swift in Sources */,
@@ -1759,6 +1766,7 @@
 				B549F6741E56A92800FBAB2D /* CoreDataNativeType.swift in Sources */,
 				B509C7F51E54511B0061C547 /* ImportableAttributeType.swift in Sources */,
 				82BA18B31C4BBD3900A0916E /* ImportableUniqueObject.swift in Sources */,
+				B5A27F871E857C5300203C3E /* TransactionResult.swift in Sources */,
 				B5E1B5951CAA0C15007FD580 /* CSObjectMonitor.swift in Sources */,
 				B5ECDC2B1CA81CC700C7F112 /* CSDataStack+Transaction.swift in Sources */,
 				82BA18A11C4BBD1D00A0916E /* CoreStore.swift in Sources */,
@@ -1915,6 +1923,7 @@
 				B549F6761E56A92800FBAB2D /* CoreDataNativeType.swift in Sources */,
 				B509C7F71E54511B0061C547 /* ImportableAttributeType.swift in Sources */,
 				B5220E1F1D130810009BC71E /* CSListObserver.swift in Sources */,
+				B5A27F891E857C5300203C3E /* TransactionResult.swift in Sources */,
 				B52DD1941BE1F92500949AFE /* CoreStore.swift in Sources */,
 				B52DD1A61BE1F92F00949AFE /* BaseDataTransaction+Importing.swift in Sources */,
 				B5220E1D1D13080A009BC71E /* CSDataStack+Observing.swift in Sources */,
@@ -2071,6 +2080,7 @@
 				B549F6751E56A92800FBAB2D /* CoreDataNativeType.swift in Sources */,
 				B509C7F61E54511B0061C547 /* ImportableAttributeType.swift in Sources */,
 				B5E1B5961CAA0C15007FD580 /* CSObjectMonitor.swift in Sources */,
+				B5A27F881E857C5300203C3E /* TransactionResult.swift in Sources */,
 				B5ECDC2C1CA81CC700C7F112 /* CSDataStack+Transaction.swift in Sources */,
 				B56321911BD65216006C9394 /* BaseDataTransaction+Importing.swift in Sources */,
 				B546F95A1C99B17400D5AC55 /* CSCoreStore+Setup.swift in Sources */,

CoreStoreTests/TransactionTests.swift

@@ -42,7 +42,7 @@ final class TransactionTests: BaseTestCase {
             do {
                 
                 let createExpectation = self.expectation(description: "create")
-                let hasChanges: Bool = stack.perform(
+                let hasChanges: Bool = try! stack.perform(
                     synchronous: { (transaction) in
                     
                         defer {
@@ -84,7 +84,7 @@ final class TransactionTests: BaseTestCase {
             do {
                 
                 let updateExpectation = self.expectation(description: "update")
-                let hasChanges: Bool = stack.perform(
+                let hasChanges: Bool = try! stack.perform(
                     synchronous: { (transaction) in
                         
                         defer {
@@ -92,9 +92,9 @@ final class TransactionTests: BaseTestCase {
                             updateExpectation.fulfill()
                         }
                         guard let object = transaction.fetchOne(From<TestEntity1>()) else {
-                            
+                            // TODO: convert fetch methods to throwing methods
-                            XCTFail()
+                            XCTFail() 
-                            return // TODO: convert fetch methods to throwing methods
+                            try transaction.cancel()
                         }
                         object.testString = "string1_edit"
                         object.testNumber = 200

Sources/Fetching and Querying/QueryableAttributeType.swift

@@ -55,6 +55,7 @@ extension NSManagedObjectID: QueryableAttributeType {
     @nonobjc @inline(__always)
     public class func cs_fromQueryableNativeType(_ value: QueryableNativeType) -> Self? {
         
+        @inline(__always)
         func forceCast<T: NSManagedObjectID>(_ value: Any) -> T? {
             
             return value as? T
@@ -84,6 +85,7 @@ extension NSNumber: QueryableAttributeType {
     @nonobjc @inline(__always)
     public class func cs_fromQueryableNativeType(_ value: QueryableNativeType) -> Self? {
         
+        @inline(__always)
         func forceCast<T: NSNumber>(_ value: Any) -> T? {
             
             return value as? T
@@ -121,6 +123,7 @@ extension NSString: QueryableAttributeType {
     @nonobjc @inline(__always)
     public class func cs_fromQueryableNativeType(_ value: QueryableNativeType) -> Self? {
         
+        @inline(__always)
         func forceCast<T: NSString>(_ value: Any) -> T? {
             
             return value as? T
@@ -147,6 +150,7 @@ extension NSDate: QueryableAttributeType {
     @nonobjc @inline(__always)
     public class func cs_fromQueryableNativeType(_ value: QueryableNativeType) -> Self? {
         
+        @inline(__always)
         func forceCast<T: NSDate>(_ value: Any) -> T? {
             
             return value as? T
@@ -173,6 +177,7 @@ extension NSData: QueryableAttributeType {
     @nonobjc @inline(__always)
     public class func cs_fromQueryableNativeType(_ value: QueryableNativeType) -> Self? {
         
+        @inline(__always)
         func forceCast<T: NSData>(_ value: Any) -> T? {
             
             return value as? T
@@ -204,7 +209,7 @@ extension Bool: QueryableAttributeType {
         case let decimal as NSDecimalNumber:
             // iOS: NSDecimalNumber(string: "0.5").boolValue // true
             // OSX: NSDecimalNumber(string: "0.5").boolValue // false
-            return NSNumber(value: decimal.doubleValue).boolValue
+            return decimal != NSDecimalNumber.zero
             
         default:
             return value.boolValue

Sources/Importing/ImportableAttributeType.swift

@@ -59,17 +59,13 @@ extension NSNumber: ImportableAttributeType {
     @nonobjc @inline(__always)
     public class func cs_fromImportableNativeType(_ value: ImportableNativeType) -> Self? {
         
-        func forceCast<T: NSNumber>(_ value: Any) -> T? {
+        return self.cs_fromQueryableNativeType(value)
-            
-            return value as? T
-        }
-        return forceCast(value)
     }
     
     @nonobjc @inline(__always)
     public func cs_toImportableNativeType() -> ImportableNativeType {
         
-        return self
+        return self.cs_toQueryableNativeType()
     }
 }
 
@@ -89,17 +85,13 @@ extension NSString: ImportableAttributeType {
     @nonobjc @inline(__always)
     public class func cs_fromImportableNativeType(_ value: ImportableNativeType) -> Self? {
         
-        func forceCast<T: NSString>(_ value: Any) -> T? {
+        return self.cs_fromQueryableNativeType(value)
-            
-            return value as? T
-        }
-        return forceCast(value)
     }
     
     @nonobjc @inline(__always)
     public func cs_toImportableNativeType() -> ImportableNativeType {
         
-        return self
+        return self.cs_toQueryableNativeType()
     }
 }
 
@@ -119,17 +111,13 @@ extension NSDate: ImportableAttributeType {
     @nonobjc @inline(__always)
     public class func cs_fromImportableNativeType(_ value: ImportableNativeType) -> Self? {
         
-        func forceCast<T: NSDate>(_ value: Any) -> T? {
+        return self.cs_fromQueryableNativeType(value)
-            
-            return value as? T
-        }
-        return forceCast(value)
     }
     
     @nonobjc @inline(__always)
     public func cs_toImportableNativeType() -> ImportableNativeType {
         
-        return self
+        return self.cs_toQueryableNativeType()
     }
 }
 
@@ -149,17 +137,13 @@ extension NSData: ImportableAttributeType {
     @nonobjc @inline(__always)
     public class func cs_fromImportableNativeType(_ value: ImportableNativeType) -> Self? {
         
-        func forceCast<T: NSData>(_ value: Any) -> T? {
+        return self.cs_fromQueryableNativeType(value)
-            
-            return value as? T
-        }
-        return forceCast(value)
     }
     
     @nonobjc @inline(__always)
     public func cs_toImportableNativeType() -> ImportableNativeType {
         
-        return self
+        return self.cs_toQueryableNativeType()
     }
 }
 
@@ -179,22 +163,13 @@ extension Bool: ImportableAttributeType {
     @inline(__always)
     public static func cs_fromImportableNativeType(_ value: ImportableNativeType) -> Bool? {
         
-        switch value {
+        return self.cs_fromQueryableNativeType(value)
-            
-        case let decimal as NSDecimalNumber:
-            // iOS: NSDecimalNumber(string: "0.5").boolValue // true
-            // OSX: NSDecimalNumber(string: "0.5").boolValue // false
-            return decimal != NSDecimalNumber.zero
-            
-        default:
-            return value.boolValue
-        }
     }
     
     @inline(__always)
     public func cs_toImportableNativeType() -> ImportableNativeType {
         
-        return self as NSNumber
+        return self.cs_toQueryableNativeType()
     }
 }
 
@@ -214,13 +189,13 @@ extension Int16: ImportableAttributeType {
     @inline(__always)
     public static func cs_fromImportableNativeType(_ value: ImportableNativeType) -> Int16? {
         
-        return value.int16Value
+        return self.cs_fromQueryableNativeType(value)
     }
     
     @inline(__always)
     public func cs_toImportableNativeType() -> ImportableNativeType {
         
-        return self as NSNumber
+        return self.cs_toQueryableNativeType()
     }
 }
 
@@ -240,13 +215,13 @@ extension Int32: ImportableAttributeType {
     @inline(__always)
     public static func cs_fromImportableNativeType(_ value: ImportableNativeType) -> Int32? {
         
-        return value.int32Value
+        return self.cs_fromQueryableNativeType(value)
     }
     
     @inline(__always)
     public func cs_toImportableNativeType() -> ImportableNativeType {
         
-        return self as NSNumber
+        return self.cs_toQueryableNativeType()
     }
 }
 
@@ -266,13 +241,13 @@ extension Int64: ImportableAttributeType {
     @inline(__always)
     public static func cs_fromImportableNativeType(_ value: ImportableNativeType) -> Int64? {
         
-        return value.int64Value
+        return self.cs_fromQueryableNativeType(value)
     }
     
     @inline(__always)
     public func cs_toImportableNativeType() -> ImportableNativeType {
         
-        return self as NSNumber
+        return self.cs_toQueryableNativeType()
     }
 }
 
@@ -292,13 +267,13 @@ extension Double: ImportableAttributeType {
     @inline(__always)
     public static func cs_fromImportableNativeType(_ value: ImportableNativeType) -> Double? {
         
-        return value.doubleValue
+        return self.cs_fromQueryableNativeType(value)
     }
     
     @inline(__always)
     public func cs_toImportableNativeType() -> ImportableNativeType {
         
-        return self as NSNumber
+        return self.cs_toQueryableNativeType()
     }
 }
 
@@ -318,13 +293,13 @@ extension Float: ImportableAttributeType {
     @inline(__always)
     public static func cs_fromImportableNativeType(_ value: ImportableNativeType) -> Float? {
         
-        return value.floatValue
+        return self.cs_fromQueryableNativeType(value)
     }
     
     @inline(__always)
     public func cs_toImportableNativeType() -> ImportableNativeType {
         
-        return self as NSNumber
+        return self.cs_toQueryableNativeType()
     }
 }
 
@@ -344,13 +319,13 @@ extension Date: ImportableAttributeType {
     @inline(__always)
     public static func cs_fromImportableNativeType(_ value: ImportableNativeType) -> Date? {
         
-        return value as Date
+        return self.cs_fromQueryableNativeType(value)
     }
     
     @inline(__always)
     public func cs_toImportableNativeType() -> ImportableNativeType {
         
-        return self as NSDate
+        return self.cs_toQueryableNativeType()
     }
 }
 
@@ -370,13 +345,13 @@ extension String: ImportableAttributeType {
     @inline(__always)
     public static func cs_fromImportableNativeType(_ value: ImportableNativeType) -> String? {
         
-        return value as String
+        return self.cs_fromQueryableNativeType(value)
     }
     
     @inline(__always)
     public func cs_toImportableNativeType() -> ImportableNativeType {
         
-        return self as NSString
+        return self.cs_toQueryableNativeType()
     }
 }
 
@@ -396,12 +371,12 @@ extension Data: ImportableAttributeType {
     @inline(__always)
     public static func cs_fromImportableNativeType(_ value: ImportableNativeType) -> Data? {
         
-        return value as Data
+        return self.cs_fromQueryableNativeType(value)
     }
     
     @inline(__always)
     public func cs_toImportableNativeType() -> ImportableNativeType {
         
-        return self as NSData
+        return self.cs_toQueryableNativeType()
     }
 }

Sources/Internal/CoreStoreFetchRequest+CoreStore.swift

@@ -33,7 +33,7 @@ internal extension CoreStoreFetchRequest {
     
     // MARK: Internal
     
-    @nonobjc
+    @nonobjc @inline(__always)
     internal func dynamicCast<U: NSFetchRequestResult>() -> NSFetchRequest<U> {
         
         return unsafeBitCast(self, to: NSFetchRequest<U>.self)

Sources/Internal/DispatchQueue+CoreStore.swift

@@ -30,7 +30,7 @@ import Foundation
 
 internal extension DispatchQueue {
     
-    @nonobjc
+    @nonobjc @inline(__always)
     internal static func serial(_ label: String, qos: DispatchQoS = .default) -> DispatchQueue {
         
         return DispatchQueue(
@@ -42,7 +42,7 @@ internal extension DispatchQueue {
         )
     }
     
-    @nonobjc
+    @nonobjc @inline(__always)
     internal static func concurrent(_ label: String, qos: DispatchQoS = .default) -> DispatchQueue {
         
         return DispatchQueue(
@@ -54,7 +54,7 @@ internal extension DispatchQueue {
         )
     }
     
-    @nonobjc
+    @nonobjc @inline(__always)
     internal func cs_isCurrentExecutionContext() -> Bool {
         
         let specific = ObjectIdentifier(self)
@@ -63,25 +63,25 @@ internal extension DispatchQueue {
         return DispatchQueue.getSpecific(key: Static.specificKey) == specific
     }
     
-    @nonobjc
+    @nonobjc @inline(__always)
     internal func cs_sync<T>(_ closure: () throws -> T) rethrows -> T {
         
         return try self.sync { try autoreleasepool(invoking: closure) }
     }
     
-    @nonobjc
+    @nonobjc @inline(__always)
     internal func cs_async(_ closure: @escaping () -> Void) {
         
         self.async { autoreleasepool(invoking: closure) }
     }
     
-    @nonobjc
+    @nonobjc @inline(__always)
     internal func cs_barrierSync<T>(_ closure: () throws -> T) rethrows -> T {
         
         return try self.sync(flags: .barrier) { try autoreleasepool(invoking: closure) }
     }
     
-    @nonobjc
+    @nonobjc @inline(__always)
     internal func cs_barrierAsync(_ closure: @escaping () -> Void) {
         
         self.async(flags: .barrier) { autoreleasepool(invoking: closure) }

Sources/Internal/Functions.swift

@@ -27,6 +27,7 @@ import Foundation
 
 // MARK: Associated Objects
 
+@inline(__always)
 internal func cs_getAssociatedObjectForKey<T: AnyObject>(_ key: UnsafeRawPointer, inObject object: Any) -> T? {
     
     switch objc_getAssociatedObject(object, key) {
@@ -42,16 +43,19 @@ internal func cs_getAssociatedObjectForKey<T: AnyObject>(_ key: UnsafeRawPointer
     }
 }
 
+@inline(__always)
 internal func cs_setAssociatedRetainedObject<T: AnyObject>(_ associatedObject: T?, forKey key: UnsafeRawPointer, inObject object: Any) {
     
     objc_setAssociatedObject(object, key, associatedObject, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
 }
 
+@inline(__always)
 internal func cs_setAssociatedCopiedObject<T: AnyObject>(_ associatedObject: T?, forKey key: UnsafeRawPointer, inObject object: Any) {
     
     objc_setAssociatedObject(object, key, associatedObject, .OBJC_ASSOCIATION_COPY_NONATOMIC)
 }
 
+@inline(__always)
 internal func cs_setAssociatedWeakObject<T: AnyObject>(_ associatedObject: T?, forKey key: UnsafeRawPointer, inObject object: Any) {
     
     if let associatedObject = associatedObject {
@@ -67,26 +71,31 @@ internal func cs_setAssociatedWeakObject<T: AnyObject>(_ associatedObject: T?, f
 
 // MARK: Printing Utilities
 
+@inline(__always)
 internal func cs_typeName<T>(_ value: T) -> String {
     
     return "'\(String(reflecting: type(of: value)))'"
 }
 
+@inline(__always)
 internal func cs_typeName<T>(_ value: T.Type) -> String {
     
     return "'\(value)'"
 }
 
+@inline(__always)
 internal func cs_typeName(_ value: AnyClass) -> String {
     
     return "'\(value)'"
 }
 
+@inline(__always)
 internal func cs_typeName(_ name: String) -> String {
     
     return "<\(name)>"
 }
 
+@inline(__always)
 internal func cs_typeName(_ name: String?) -> String {
     
     return "<\(name ?? "unknown")>"

Sources/Transactions/AsynchronousDataTransaction.swift

@@ -34,6 +34,11 @@ import CoreData
  */
 public final class AsynchronousDataTransaction: BaseDataTransaction {
     
+    public func cancel() throws -> Never {
+        
+        throw CoreStoreError.userCancelled
+    }
+    
     /**
      Saves the transaction changes. This method should not be used after the `commit()` method was already called once.
      

Sources/Transactions/BaseDataTransaction.swift

@@ -36,12 +36,6 @@ public /*abstract*/ class BaseDataTransaction {
     
     // MARK: Object management
     
-    
-    public func cancel() throws -> Never {
-        
-        throw CoreStoreError.userCancelled
-    }
-    
     /**
      Indicates if the transaction has pending changes
      */

Sources/Transactions/DataStack+Transaction.swift

@@ -31,6 +31,16 @@ import CoreData
 
 public extension DataStack {
     
+    
+    public func perform<T>(asynchronous task: @escaping (_ transaction: AsynchronousDataTransaction) throws -> T, completion: @escaping (TransactionResult<T>) -> Void) {
+        
+        self.perform(
+            asynchronous: task,
+            success: { completion(TransactionResult(userInfo: $0)) },
+            failure: { completion(TransactionResult(error: $0)) }
+        )
+    }
+    
     public func perform<T>(asynchronous task: @escaping (_ transaction: AsynchronousDataTransaction) throws -> T, success: @escaping (T) -> Void, failure: @escaping (CoreStoreError) -> Void) {
         
         let transaction = AsynchronousDataTransaction(
@@ -40,28 +50,28 @@ public extension DataStack {
         )
         transaction.transactionQueue.cs_async {
             
+            let userInfo: T
             do {
                 
-                let extraInfo = try task(transaction)
+                userInfo = try task(transaction)
-                transaction.commit { (result) in
-                    
-                    switch result {
-                        
-                    case .success:
-                        success(extraInfo)
-                        
-                    case .failure(let error):
-                        failure(error)
-                    }
-                }
             }
             catch let error as CoreStoreError {
                 
                 DispatchQueue.main.async { failure(error) }
+                return
             }
             catch let error {
                 
                 DispatchQueue.main.async { failure(.userError(error: error)) }
+                return
+            }
+            transaction.commit { (result) in
+                
+                switch result {
+                    
+                case .success: success(userInfo)
+                case .failure(let error): failure(error)
+                }
             }
         }
     }
@@ -75,10 +85,10 @@ public extension DataStack {
         )
         return try transaction.transactionQueue.cs_sync {
             
-            let extraInfo: T
+            let userInfo: T
             do {
                 
-                extraInfo = try task(transaction)
+                userInfo = try task(transaction)
             }
             catch let error as CoreStoreError {
                 
@@ -88,17 +98,13 @@ public extension DataStack {
                 
                 throw CoreStoreError.userError(error: error)
             }
-            
             let result = waitForObserverNotifications
                 ? transaction.commitAndWait()
                 : transaction.commit()
             switch result {
                 
-            case .success:
+            case .success: return userInfo
-                return extraInfo
+            case .failure(let error): throw error
-                
-            case .failure(let error):
-                throw error
             }
         }
     }

Sources/Transactions/SynchronousDataTransaction.swift

@@ -34,6 +34,11 @@ import CoreData
  */
 public final class SynchronousDataTransaction: BaseDataTransaction {
     
+    public func cancel() throws -> Never {
+        
+        throw CoreStoreError.userCancelled
+    }
+    
     /**
      Saves the transaction changes and waits for completion synchronously. This method should not be used after the `commit()` or `commitAndWait()` method was already called once.
      - Important: Unlike `SynchronousDataTransaction.commit()`, this method waits for all observers to be notified of the changes before returning. This results in more predictable data update order, but may risk triggering deadlocks.

Sources/Transactions/TransactionResult.swift

@@ -0,0 +1,58 @@
+//
+//  TransactionResult.swift
+//  CoreStore
+//
+//  Copyright © 2017 John Rommel Estropia
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in all
+//  copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+//  SOFTWARE.
+//
+
+import Foundation
+
+
+// MARK: - TransactionResult
+
+public enum TransactionResult<T> {
+
+    case success(T)
+
+    case failure(CoreStoreError)
+
+    public var boolValue: Bool {
+
+        switch self {
+
+        case .success: return true
+        case .failure: return false
+        }
+    }
+
+
+    // MARK: Internal
+
+    internal init(userInfo: T) {
+
+        self = .success(userInfo)
+    }
+
+    internal init(error: CoreStoreError) {
+
+        self = .failure(error)
+    }
+}