[AltStore] Tracks background refresh attempts for debugging

AltStore/Model/RefreshAttempt.swift

@@ -0,0 +1,51 @@
+//
+//  RefreshAttempt.swift
+//  AltStore
+//
+//  Created by Riley Testut on 7/31/19.
+//  Copyright © 2019 Riley Testut. All rights reserved.
+//
+
+import CoreData
+
+@objc(RefreshAttempt)
+class RefreshAttempt: NSManagedObject, Fetchable
+{
+    @NSManaged var identifier: String
+    @NSManaged var date: Date
+    
+    @NSManaged var isSuccess: Bool
+    @NSManaged var errorDescription: String?
+    
+    private override init(entity: NSEntityDescription, insertInto context: NSManagedObjectContext?)
+    {
+        super.init(entity: entity, insertInto: context)
+    }
+    
+    init<T>(identifier: String, result: Result<T, Error>, context: NSManagedObjectContext)
+    {
+        super.init(entity: RefreshAttempt.entity(), insertInto: context)
+        
+        self.identifier = identifier
+        self.date = Date()
+        
+        switch result
+        {
+        case .success:
+            self.isSuccess = true
+            self.errorDescription = nil
+            
+        case .failure(let error):
+            self.isSuccess = false
+            self.errorDescription = error.localizedDescription
+        }
+    }
+}
+
+extension RefreshAttempt
+{
+    @nonobjc class func fetchRequest() -> NSFetchRequest<RefreshAttempt>
+    {
+        return NSFetchRequest<RefreshAttempt>(entityName: "RefreshAttempt")
+    }
+}