sisoje

class DeinitBlock {
    let onDeinit: () -> Void
    init(_ block: @escaping () -> Void) {
        onDeinit = block
    }
    deinit {
        onDeinit()
    }
}

sisoje

extension URLSessionDataTask {
    var cancellation: DeinitBlock {
        return DeinitBlock { [weak self] in
            self?.cancel()
        }
    }
}

sisoje

class URLImageTableViewCell: UITableViewCell {
    @IBOutlet weak var urlImageView: UIImageView!    
    
    var urlImageLoader: DeinitBlock?

    // new task is created, old task cancelled automatically
    func setImage(url: URL) {
        urlImageLoader = urlImageView.setCachedImage(url: url)
    }
}

sisoje

extension Timer {
    var invalidation: DeinitBlock {
        return DeinitBlock { [weak self] in
            self?.invalidate()
        }
    }
}

sisoje

import CoreData

public final class CoreDataStack {
    public let persistentContainer: NSPersistentContainer
    
    public init(_ persistentContainer: NSPersistentContainer) {
        self.persistentContainer = persistentContainer
    }
    
    public private(set) lazy var mainContext: NSManagedObjectContext = {

sisoje

extension NSManagedObjectContext {
    func performTask(_ block: @escaping (NSManagedObjectContext) -> Void) {
        perform { [unowned self] in
            block(self)
        }
    }
}

sisoje

extension NSFetchedResultsController {
    var sectionCount: Int {
        return sections?.count ?? 0
    }
}

sisoje

extension NSFetchedResultsController {
    @objc func entity(at row: Int) -> ResultType {
        object(at: IndexPath(item: row, section: 0))
    }
}

sisoje

class FetchedData<T: NSFetchRequestResult> {
    let controller: NSFetchedResultsController<T>
    init(_ controller: NSFetchedResultsController<T>) {
        self.controller = controller
    }
}

sisoje

extension FetchedData {
    subscript(_ indexPath: IndexPath) -> T {
        return controller.object(at: indexPath)
    }
}