Thread handling

Classes/CoreData.swift

@@ -42,14 +42,35 @@ public class CoreData {
 
     // MARK: Basic methods
 
+    private var _privateManagedContext: NSManagedObjectContext?
+    private var _managedContext: NSManagedObjectContext?
+
+    /// Private managed object context for this instance
+    public lazy var privateManagedContext: NSManagedObjectContext = {
+        guard let privateManagedContext = _privateManagedContext else {
+            // Create a background managed context as root context so the
+            // main thread should not be blocked on more expensive opersations
+            let privateManagedContext = persistentContainer.newBackgroundContext()
+            _privateManagedContext = privateManagedContext
+            return privateManagedContext
+        }
+        return privateManagedContext
+    }()
+
     /// Managed context for this instance
-    public var managedContext: NSManagedObjectContext {
-        return persistentContainer.viewContext
-    }
+    public lazy var managedContext: NSManagedObjectContext = {
+        guard let managedContext = _managedContext else {
+            let managedContext = NSManagedObjectContext(concurrencyType: .mainQueueConcurrencyType)
+            managedContext.parent = privateManagedContext
+            _managedContext = managedContext
+            return managedContext
+        }
+        return managedContext
+    }()
 
     /// Default managed context
     public static var managedContext: NSManagedObjectContext {
-        return CoreData.default.persistentContainer.viewContext
+        return CoreData.default.managedContext
     }
 
     /// Create new entry on the default context
@@ -78,12 +99,12 @@ public class CoreData {
 
     /// Save managed context if it has changes
     public func saveContext() throws {
-        try CoreData.save(context: managedContext)
+        try CoreData.save(context: privateManagedContext)
     }
 
     /// Save default managed context if it has changes
     public static func saveContext() throws {
-        try CoreData.save(context: managedContext)
+        try CoreData.default.saveContext()
     }
 
     // MARK: Private interface

Classes/Extensions/QueryExecutable+ManagedObject.swift

@@ -0,0 +1,55 @@
+//
+//  QueryExecutable+ManagedObject.swift
+//  Reloaded
+//
+//  Created by Ondrej Rafaj on 10/05/2018.
+//  Copyright © 2018 LiveUI. All rights reserved.
+//
+
+import Foundation
+import CoreData
+
+
+extension QueryExecutable where EntityType: NSManagedObject {
+
+    /// Return all data based on your query
+    public func all(on context: NSManagedObjectContext?) throws -> [EntityType] {
+        let context = context ??  CoreData.managedContext
+        guard let data = try context.fetch(fetchRequest()) as? [EntityType] else {
+            return []
+        }
+        return data
+    }
+
+    /// Delete all data captured by your query
+    public func delete(on context: NSManagedObjectContext?) throws {
+        let context = context ??  CoreData.managedContext
+        for object in try all(on: context) {
+            try object.delete(on: context)
+        }
+        try context.save()
+
+// TODO: Fix the following batch request!
+//        let deleteRequest = NSBatchDeleteRequest(fetchRequest: fetchRequest())
+//        do {
+//            let batchDeleteResult = try context.execute(deleteRequest) as! NSBatchDeleteResult
+//            print("The batch delete request has deleted \(batchDeleteResult.result!) records.")
+//        } catch {
+//            let updateError = error as NSError
+//            print("\(updateError), \(updateError.userInfo)")
+//        }
+    }
+
+    /// Count the number of items in your query
+    public func count(on context: NSManagedObjectContext?) throws -> Int {
+        let context = context ??  CoreData.managedContext
+        return try context.count(for: fetchRequest())
+    }
+
+    /// Get first result of your query
+    public func first(on context: NSManagedObjectContext?) throws -> EntityType? {
+        let context = context ??  CoreData.managedContext
+        return try context.fetch(fetchRequest()).first as? EntityType
+    }
+
+}

Classes/Extensions/QueryExecutable+Threading.swift

@@ -0,0 +1,41 @@
+//
+//  QueryExecutable+Threading.swift
+//  Reloaded
+//
+//  Created by Ondrej Rafaj on 10/05/2018.
+//  Copyright © 2018 LiveUI. All rights reserved.
+//
+
+import Foundation
+import CoreData
+
+
+extension QueryExecutable where EntityType: NSManagedObject {
+
+    /// Return all data based on your query
+    public func all(on queue: DispatchQueue = .main) -> CoreDataPromise<[EntityType]> {
+        // Create or get the right context for the desired queue
+        // Execute query on the thread for the context
+        // Fulfill promise
+        // Dispose of the context if no-one is using it anymore
+        fatalError()
+    }
+
+    /// Delete all data captured by your query
+    public func delete(on queue: DispatchQueue = .main) -> CoreDataPromise<Void> {
+        // All above +
+        // Update all contexts
+        fatalError()
+    }
+
+    /// Count the number of items in your query
+    public func count(on queue: DispatchQueue = .main) -> CoreDataPromise<Int>{
+        fatalError()
+    }
+
+    /// Get first result of your query
+    public func first(on queue: DispatchQueue = .main) -> CoreDataPromise<EntityType?> {
+        fatalError()
+    }
+
+}

Classes/Libs/CoreDataPromise.swift

@@ -0,0 +1,49 @@
+//
+//  CoreDataPromise.swift
+//  Reloaded
+//
+//  Created by Ondrej Rafaj on 10/05/2018.
+//  Copyright © 2018 LiveUI. All rights reserved.
+//
+
+import Foundation
+
+
+public class CoreDataPromise<Expectation> {
+
+    public internal(set) var expectation: Expectation? {
+        didSet {
+            if let expectation = expectation {
+                thenPromiseClosure?(expectation)
+                mapPromise?.expectation = mapPromiseClosure?(expectation)
+            }
+        }
+    }
+
+    /// Then closure type
+    public typealias ThenPromise = ((Expectation) -> Void)
+
+    /// Map closure type
+    public typealias MapPromise<T> = ((Expectation) -> T)
+
+    var thenPromiseClosure: ThenPromise?
+
+    /// Executes when operation is finished
+    public func then(_ promise: @escaping ThenPromise) -> Self {
+        thenPromiseClosure = promise
+        return self
+    }
+
+    var mapPromiseClosure: MapPromise<Any>?
+    var mapPromise: CoreDataPromise<Any>?
+
+//    /// Executes when operation is finished to transform result to another type
+//    public func map<T>(to: T.Type = T.self, _ promise: @escaping MapPromise<T>) -> CoreDataPromise<T> {
+//        mapPromiseClosure = promise
+//
+//        let mapPromise = CoreDataPromise<T>()
+//
+//        return mapPromise
+//    }
+
+}

Classes/Protocols/Entity.swift

@@ -32,7 +32,6 @@ extension Entity where Self: NSManagedObject {
 
     /// Create new query
     public static var query: Query<Self> {
-        print(self)
         return Query(self)
     }
 

Classes/Protocols/QueryExecutable.swift

@@ -40,38 +40,3 @@ extension QueryExecutable {
     }
 
 }
-
-extension QueryExecutable where EntityType: NSManagedObject {
-
-    public func all(on context: NSManagedObjectContext = CoreData.managedContext) throws -> [EntityType] {
-        guard let data = try context.fetch(fetchRequest()) as? [EntityType] else {
-            return []
-        }
-        return data
-    }
-
-    public func delete(on context: NSManagedObjectContext = CoreData.managedContext) throws {
-        for object in try all(on: context) {
-            try object.delete(on: context)
-        }
-        try context.save()
-
-//        let deleteRequest = NSBatchDeleteRequest(fetchRequest: fetchRequest())
-//        do {
-//            let batchDeleteResult = try context.execute(deleteRequest) as! NSBatchDeleteResult
-//            print("The batch delete request has deleted \(batchDeleteResult.result!) records.")
-//        } catch {
-//            let updateError = error as NSError
-//            print("\(updateError), \(updateError.userInfo)")
-//        }
-    }
-
-    public func count(on context: NSManagedObjectContext = CoreData.managedContext) throws -> Int {
-        return try context.count(for: fetchRequest())
-    }
-
-    public func first(on context: NSManagedObjectContext = CoreData.managedContext) throws -> EntityType? {
-        return try context.fetch(fetchRequest()).first as? EntityType
-    }
-
-}

Demo-iOS/ViewController.swift

@@ -31,6 +31,9 @@ class ViewController: UIViewController {
         }
 
         let all = try! Locomotive.query.filter("hasChimney" == true).filter(.or, "color" == "green", "color" == "black").sort(by: "color", direction: .orderedAscending).all()
+        all.forEach { (<#Collection.Element#>) in
+            <#code#>
+        }
         all.forEach { loco in
             print("Color: \(loco.color ?? "Unknown"); Chimney: \(Bool(loco.hasChimney))")
         }

Reloaded.podspec

@@ -8,7 +8,7 @@
 
 Pod::Spec.new do |s|
     s.name             = 'Reloaded'
-    s.version          = '1.0.1'
+    s.version          = '1.1.0'
     s.summary          = 'Reloaded! Swift "ORM like" abstraction layer for CoreData'
     s.swift_version    = '4.0'