feat: load quads using new background context

Memola/Canvas/Contexts/GraphicContext.swift

@@ -62,13 +62,21 @@ final class GraphicContext: @unchecked Sendable {
 extension GraphicContext {
     func loadStrokes(_ bounds: CGRect) {
         guard let object else { return }
+        let queue = OperationQueue()
+        queue.qualityOfService = .userInteractive
         self.strokes = object.strokes.compactMap { stroke -> Stroke? in
             guard let stroke = stroke as? StrokeObject else { return nil }
             let _stroke = Stroke(object: stroke)
             if _stroke.isVisible(in: bounds) {
-                _stroke.loadQuads()
-                withPersistence(\.backgroundContext) { [stroke] context in
-                    context.refresh(stroke, mergeChanges: false)
+                let id = stroke.objectID
+                queue.addOperation {
+                    withPersistenceSync(\.newBackgroundContext) { [_stroke] context in
+                        guard let stroke = try? context.existingObject(with: id) as? StrokeObject else { return }
+                        _stroke.loadQuads(from: stroke)
+                    }
+                    withPersistence(\.backgroundContext) { [stroke] context in
+                        context.refresh(stroke, mergeChanges: false)
+                    }
                 }
             } else {
                 withPersistence(\.backgroundContext) { [stroke] context in
@@ -78,6 +86,7 @@ extension GraphicContext {
             }
             return _stroke
         }
+        queue.waitUntilAllOperationsAreFinished()
     }
 
     func loadQuads(_ bounds: CGRect) {

Memola/Canvas/Geometries/Stroke/Stroke.swift

@@ -98,6 +98,13 @@ extension Stroke {
         }
     }
 
+    func loadQuads(from object: StrokeObject) {
+        quads = object.quads.compactMap { quad in
+            guard let quad = quad as? QuadObject else { return nil }
+            return Quad(object: quad)
+        }
+    }
+
     func addQuad(at point: CGPoint, rotation: CGFloat, shape: QuadShape) -> Quad {
         let quad = Quad(
             origin: point,

Memola/Persistence/Core/Persistence.swift

@@ -26,6 +26,13 @@ final class Persistence {
         return context
     }()
 
+    var newBackgroundContext: NSManagedObjectContext {
+        let context = persistentContainer.newBackgroundContext()
+        context.undoManager = nil
+        context.automaticallyMergesChangesFromParent = true
+        return context
+    }
+
     lazy var persistentContainer: NSPersistentContainer = {
         let persistentStore = NSPersistentStoreDescription()
         persistentStore.shouldMigrateStoreAutomatically = true
@@ -83,3 +90,14 @@ func withPersistence(_ keypath: KeyPath<Persistence, NSManagedObjectContext>, _
         }
     }
 }
+
+func withPersistenceSync(_ keypath: KeyPath<Persistence, NSManagedObjectContext>, _ task: @escaping (NSManagedObjectContext) throws -> Void) {
+    let context = Persistence.shared[keyPath: keypath]
+    context.performAndWait {
+        do {
+            try task(context)
+        } catch {
+            NSLog("[Memola] - \(error.localizedDescription)")
+        }
+    }
+}