Add logging via a Logger instead of just a println

Author: mac-cain13

CoreDataKit/CoreDataKit.swift

@@ -8,13 +8,23 @@
 
 import CoreData
 
+public enum LogLevel {
+    case DEBUG
+    case INFO
+    case WARN
+    case ERROR
+}
+
+public typealias Logger = (LogLevel, String) -> Void
+
 /**
 `CoreDataKit` helps with setup of the CoreData stack
 */
 public class CoreDataKit : NSObject
 {
     private struct Holder {
         static var sharedStack: CoreDataStack?
+        static var sharedLogger: Logger = { _, message in println("[CoreDataKit] \(message)") }
     }
 
     /**
@@ -32,6 +42,21 @@ public class CoreDataKit : NSObject
         }
     }
 
+    /**
+    Shared logger used by CoreDataKit to log messages.
+    
+    :discussion: Default logger prints messages to console, but you can use this to use your own logger
+    */
+    public class var sharedLogger: Logger {
+        get {
+            return Holder.sharedLogger
+        }
+
+        set {
+            Holder.sharedLogger = newValue
+        }
+    }
+
 // MARK: Convenience properties
 
     /// Persistent store coordinator used as backing for the contexts of the shared stack

CoreDataKit/Importing/Types+Importing.swift

@@ -31,7 +31,10 @@ let RelationTypeUserInfoKey = "CDKRelationType"
 
 /// Values used with RelationTypeUserInfoKey to alter relation type
 enum RelationType: String {
+    /// Relation that is referenced by a primary key like ID
     case RelatedById = "CDKRelatedById"
+
+    /// Relation that doesn't use a ID of some sort
     case WithoutId = "CDKWithoutId"
 
     static func fromString(string: String) -> RelationType {

CoreDataKit/NSPersistentStoreCoordinator.swift

@@ -99,7 +99,7 @@ extension NSPersistentStoreCoordinator
             // Check for version mismatch
             if (deleteOnMismatch && NSCocoaErrorDomain == error.domain && (NSPersistentStoreIncompatibleVersionHashError == error.code || NSMigrationMissingSourceModelError == error.code)) {
 
-                println("[CoreDataKit] Model mismatch, removing persistent store...")
+                CoreDataKit.sharedLogger(.WARN, "[CoreDataKit] Model mismatch, removing persistent store...")
                 if let urlString = URL.absoluteString {
                     let shmFile = urlString.stringByAppendingString("-shm")
                     let walFile = urlString.stringByAppendingString("-wal")
@@ -108,16 +108,22 @@ extension NSPersistentStoreCoordinator
                     NSFileManager.defaultManager().removeItemAtPath(walFile, error: nil)
                 }
 
-                addStore()
+                if let error = addStore().error() {
+                    CoreDataKit.sharedLogger(.ERROR, "[CoreDataKit] Failed to add SQLite persistent store: \(error)")
+                }
             }
             // Workaround for "Migration failed after first pass" error
             else if automigrating {
-                println("[CoreDataKit] Applying workaround for 'Migration failed after first pass' bug, retrying...")
+                CoreDataKit.sharedLogger(.WARN, "[CoreDataKit] Applying workaround for 'Migration failed after first pass' bug, retrying...")
                 dispatch_after(dispatch_time(DISPATCH_TIME_NOW, Int64(NSEC_PER_SEC) / 2), dispatch_get_main_queue()) {
-                    addStore()
-                    return
+                    if let error = addStore().error() {
+                        CoreDataKit.sharedLogger(.ERROR, "[CoreDataKit] Failed to add SQLite persistent store: \(error)")
+                    }
                 }
             }
+            else {
+                CoreDataKit.sharedLogger(.ERROR, "[CoreDataKit] Failed to add SQLite persistent store: \(error)")
+            }
         }
     }
 }