Create swift package

Sources/SideStoreCore/Protocols/Fetchable.swift

@@ -0,0 +1,64 @@
+//
+//  NSManagedObject+Conveniences.swift
+//  AltStore
+//
+//  Created by Riley Testut on 6/6/19.
+//  Copyright © 2019 Riley Testut. All rights reserved.
+//
+
+import CoreData
+
+public typealias FetchRequest = NSFetchRequest<NSFetchRequestResult>
+
+public protocol Fetchable: NSManagedObject {}
+
+public extension Fetchable {
+    static func first(satisfying predicate: NSPredicate? = nil, sortedBy sortDescriptors: [NSSortDescriptor]? = nil, in context: NSManagedObjectContext,
+                      requestProperties: [PartialKeyPath<FetchRequest>: Any?] = [:]) -> Self? {
+        let managedObjects = Self.all(satisfying: predicate, sortedBy: sortDescriptors, in: context, requestProperties: requestProperties, returnFirstResult: true)
+        return managedObjects.first
+    }
+
+    static func all(satisfying predicate: NSPredicate? = nil, sortedBy sortDescriptors: [NSSortDescriptor]? = nil, in context: NSManagedObjectContext,
+                    requestProperties: [PartialKeyPath<FetchRequest>: Any?] = [:]) -> [Self] {
+        let managedObjects = Self.all(satisfying: predicate, sortedBy: sortDescriptors, in: context, requestProperties: requestProperties, returnFirstResult: false)
+        return managedObjects
+    }
+
+    static func fetch(_ fetchRequest: NSFetchRequest<Self>, in context: NSManagedObjectContext) -> [Self] {
+        do {
+            let managedObjects = try context.fetch(fetchRequest)
+            return managedObjects
+        } catch {
+            print("Failed to fetch managed objects. Fetch Request: \(fetchRequest). Error: \(error).")
+            return []
+        }
+    }
+
+    private static func all(satisfying predicate: NSPredicate? = nil, sortedBy sortDescriptors: [NSSortDescriptor]? = nil, in context: NSManagedObjectContext, requestProperties: [PartialKeyPath<FetchRequest>: Any?], returnFirstResult: Bool) -> [Self] {
+        let registeredObjects = context.registeredObjects.lazy.compactMap { $0 as? Self }.filter { predicate?.evaluate(with: $0) != false }
+
+        if let managedObject = registeredObjects.first, returnFirstResult {
+            return [managedObject]
+        }
+
+        let fetchRequest = self.fetchRequest() as! NSFetchRequest<Self>
+        fetchRequest.predicate = predicate
+        fetchRequest.sortDescriptors = sortDescriptors
+        fetchRequest.returnsObjectsAsFaults = false
+
+        for (keyPath, value) in requestProperties {
+            // Still no easy way to cast PartialKeyPath back to usable WritableKeyPath :(
+            guard let objcKeyString = keyPath._kvcKeyPathString else { continue }
+            fetchRequest.setValue(value, forKey: objcKeyString)
+        }
+
+        let fetchedObjects = fetch(fetchRequest, in: context)
+
+        if let fetchedObject = fetchedObjects.first, returnFirstResult {
+            return [fetchedObject]
+        } else {
+            return fetchedObjects
+        }
+    }
+}