source-code

source-code/ALTs/AltStore/Protocols/Fetchable.swift

@@ -0,0 +1,79 @@
+//
+//  NSManagedObject+Conveniences.swift
+//  AltStore
+//
+//  Created by Riley Testut on 6/6/19.
+//  Copyright © 2019 Riley Testut. All rights reserved.
+//
+
+import CoreData
+
+typealias FetchRequest = NSFetchRequest<NSFetchRequestResult>
+
+protocol Fetchable: NSManagedObject
+{
+}
+
+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 = self.fetch(fetchRequest, in: context)
+        
+        if let fetchedObject = fetchedObjects.first, returnFirstResult
+        {
+            return [fetchedObject]
+        }
+        else
+        {
+            return fetchedObjects
+        }
+    }
+}