I have the following method in NSOperationQueue category:- (void)addOperation:(NSOperation *)op withDelayInNanoseconds:(int64_t)nanoseconds { int64_t delay = (self.operationCount * nanoseconds); int64_t timeInterval = (int64_t)(nanoseconds + delay); int64_t boundTimeInterval = timeInterval >= 0 ? timeInterval : 0; __weak typeof(self) weakSelf = self; NSLog(@"%@ addOperation: %@ intoQueue: %@ withOperationDelayInNanoseconds: %@ boundTimeInterval: %@. operationCount: %@", weakSelf.debugDescription, op, weakSelf.underlyingQueue, @(nanoseconds), @(boundTimeInterval), @(weakSelf.operationCount)); //uderlyingQueue could be nil. //maybe just add operation in queue? //https://github.com/Tricertops/GrandSwiftDispatch/issues/1 //maybe the best why is to remove such a queue :/ if (weakSelf.underlyingQueue == nil) { NSLog(@"%@ underlyingQueue is %@", weakSelf.debugDescription, weakSelf.underlyingQueue); } dispatch_queue_t queue = weakSelf.underlyingQueue ?: dispatch_queue_create("com.myproject.concurrency", NULL); dispatch_after(dispatch_time(DISPATCH_TIME_NOW, boundTimeInterval), queue, ^{ [weakSelf addOperation:op]; }); }It may not work ( not sure how it works. )But in this code I encountered self.unerlyingQueue value nil due to documentation.So, I put adding operation in dispatch_after block and it is fires after delay.This example adds delay only before adding operation. It don't add delay gap between two operations with desired interval.Now I try to figure out how to do it.Subclass from NSOperation.@interface MyProjectDelayedOperation : NSOperation @property (assign, nonatomic, readwrite) NSInteger beforeDelayInSeconds; @property (assign, nonatomic, readwrite) NSInteger afterDelayInSeconds; @end @interface MyProjectDelayedOperation () @property (strong, readwrite) NSOperation *operation; @property (readwrite, getter=isCancelled) BOOL cancelled; @property (readwrite, getter=isExecuting) BOOL executing; @property (readwrite, getter=isFinished) BOOL finished; //@property (readonly, getter=isConcurrent) BOOL concurrent; // To be deprecated; use and override 'asynchronous' below //@property (readonly, getter=isAsynchronous) BOOL asynchronous NS_AVAILABLE(10_8, 7_0); @property (readonly, getter=isReady) BOOL ready; @end static const void *observerContextIsCancelled; static const void *observerContextIsFinished; @implementation MyProjectDelayedOperation - (instancetype)initWithOperation:(NSOperation *)operation { if (self = [super init]) { self.operation = operation; [self.operation addObserver:self forKeyPath:@"isCancelled" options:0 context:observerContextIsCancelled]; [self.operation addObserver:self forKeyPath:@"isFinished" options:0 context:observerContextIsFinished]; } return self; } - (void)start { // wait before start for seconds. double delayInSeconds = self.beforeDelayInSeconds; dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, (int64_t)(delayInSeconds * NSEC_PER_SEC)); __weak __typeof(self)weakSelf = self; dispatch_after(popTime, dispatch_get_main_queue(), ^(void){ [weakSelf willChangeValueForKey:@"isExecuting"]; weakSelf.executing = YES && !weakSelf.cancelled; [weakSelf didChangeValueForKey:@"isExecuting"]; if (self.executing && !self.cancelled) { [weakSelf.operation start]; } }); } // subscipt on operation values. - (void)cancel { [self willChangeValueForKey:@"isCancelled"]; self.cancelled = YES; [self didChangeValueForKey:@"isCancelled"]; if (!self.operation.cancelled) { [self.operation cancel]; } } - (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary<NSKeyValueChangeKey,id> *)change context:(void *)context { if ((object == self.operation) && (context == observerContextIsCancelled)) { [self cancel]; } else if ((object == self.operation) && (context == observerContextIsFinished)){ [self finished]; } } - (void)finished { // should wait for state "done" double delayInSeconds = self.afterDelayInSeconds; dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, (int64_t)(delayInSeconds * NSEC_PER_SEC)); __weak __typeof(self)weakSelf = self; dispatch_after(popTime, dispatch_get_main_queue(), ^(void){ [weakSelf willChangeValueForKey:@"isExecuting"]; [weakSelf willChangeValueForKey:@"isFinished"]; weakSelf.executing = NO; weakSelf.finished = YES; [weakSelf didChangeValueForKey:@"isFinished"]; [weakSelf didChangeValueForKey:@"isExecuting"]; }); } @endIt wraps operation and adds intervals before start and after finish.It listens underlying operation events isCancelled and isFinished to react on them and to fire delayed operation finish.Not sure how to add before and after delays properly.Of course, this may work with queues maximum concurrent operations value equal one. ( Serial queue )

It would be great to know the list of compatible devices for each technology.Many technologies ( ARKit, Metal, Metal 2, VR, CareKit ) and more are not compatible with old devices.And it would be great to see a list with these devices ( or an app? ) which show which technologies you don't have in case of your pretty old device.In thread I ask a question about old devices and new technologies.As I know Metal doesn't support Macbook Pro 2011 and earlier.But macOS High Sierra has Macbook Pro 2010 in compatible devices list.And as I undestand ( not correctly, I suppose ) macOS 10.13 uses Metal 2 under Window server.Is it a contradiction?

Hi! Beginning I would like to know about UIConfigurationStateCustomKey. Documentation In a documentation we can find example where CellConfiguration has been extended and later CustomCell subclass get a property to update cell if needed. A part of documentation: // Declare a custom key for a custom isArchived state. extension UIConfigurationStateCustomKey { 		static let isArchived = UIConfigurationStateCustomKey("com.my-app.MyCell.isArchived") } // Declare an extension on the cell state structure to provide a typed property for this custom state. extension UICellConfigurationState { 		var isArchived: Bool { 				get { return self[.isArchived] as? Bool ?? false } 				set { self[.isArchived] = newValue } 		} } class MyCell: UICollectionViewCell { 		// This is an existing custom property of the cell. 		var isArchived: Bool { 				didSet { 						// Ensure that an update is performed whenever this property changes. 						if oldValue != isArchived { 								setNeedsUpdateConfiguration() 						} 				} 		} } Documentation example Look at it carefully. We define custom key and, later, add stored property to ConfigurationState. But! We also define a property for MyCell, which has didSet hook with setNeedsUpdateConfiguration invocation. How do I understand this pattern? We define a custom property that could be stored in cell configuration. Later, that property can be changed by a user. So, whenever something happened ( user press a button? ), this cell object receives obj.isArchived = valueFromUser. But! If we use this approach, we also define UIContentConfiguration with our UIContentView. That means, that we have our CustomUIContentView: UIContentView with all buttons that we need. These buttons change state of an associated model object. So, we define Row with all booleans which are related/mapped to buttons on CustomUIContentView. Conclusion There is no point where we should use properties for Cells. Question Am I missing something with new API?

Hello! Description I have a ContentView which contains UITextView. I would like to use this ContentView in UICollectionViewCell. View Hierarchy UICollectionView { 	MyContentView { 		UIStackView { 			UITextView 		} 	} } As you see I add additional UIStackView that embraces UITextView. Problem When I typing in UITextView, it doesn't grow at all. But if I press on cell and apply configuration is applied to content view, everything works fine and I get correct size of textView. Code class CustomConfigurationCell: UICollectionViewCell { 		override func updateConfiguration(using state: UICellConfigurationState) { 				super.updateConfiguration(using: state) 				backgroundConfiguration = CustomBackgroundConfiguration.configuration(for: state) 		} } class MyContentView { 		private var appliedConfiguration: CustomContentConfiguration! 		 		private func apply(configuration: CustomContentConfiguration) { 				guard appliedConfiguration != configuration else { return } 				appliedConfiguration = configuration 		} } What have I tried so far? I added listeners for textViewDidChange and call all setNeedsUpdateConstraints, setNeedsLayout and other layout methods on both self ( ContentView ) and self.superview ( CustomConfigurationCell ).

Consider the following I have a method that call external library Lib. enum Service { &#9;enum Invocation { &#9;&#9;static func findBy(id: String) -> Data? { Lib.FindById(id) } &#9;} } Next, I would like to introduce a Future which wrap this call to be compatible with Combine. extension Service { static func findBy(id: String) -> Future<Data?, Never> { &#9;&#9;&#9;.init { promise in promise(Invocation.findBy(id: id)) } &#9;&#9;} } What is a proper ("Combinish") way to dispatch Invocation.findBy on a given thread/queue? I would like to dispatch this method on background thread, however, it is too expensive if I call it many times. Also if I have many Combine modifiers , the call to this method is delayed, correct? But I would like to dispatch invocation on different queue/thread as soon as possible. .subscribe(on: Scheduler) modifier doesn't change the execution queue/thread of body of future Service.findBy.

I am using Diffable Datasource in an app. I stop app at breakpoint with image loading before dispatch on background thread ( network ). I see a thread with name com.apple.uikit.datasource.diffing. It is a serial thread with number 1 and I suppose it is main thread (stack says so). However, could anybody describe a purpose of this thread and, especially, label name. Maybe it is not a main thread.

Hi! I have a closed alpha app that is distributed among developers. I use TestFlight to deliver new app version to developers. Is it possible for developers: Connect device to MacBook. Open Console.app. Filter logs by app name. Note: all these developers are invited to our AppStoreConnect team.

I have a publisher with the following signature. AnyPublisher<Never, Error> As I understand it correctly, it is impossible to change its output to something like Void to just catch this output. Actually, I want to call flatMap on this publisher and change it, but flatMap will never been called because of Never output. So... Is it possible to revert ignoreOutput()?

I have the following attempt. The main idea is to .receive(on: queue) operator with private queue However, it doesn't work as expected. Is it possible to build event bus queue with combine publishers and subjects? . swift class Work {     var cancellable: AnyCancellable?     var cancellable2: AnyCancellable?     typealias Input = Int     private var inputSubject: PassthroughSubjectInput, Never = .init()     private var inputPublisher: AnyPublisherInput, Never     init() {         let queue: DispatchQueue = .init(label: "com.abc.abc")         self.inputPublisher = self.inputSubject.receive(on: queue).eraseToAnyPublisher()         self.inputSubject     }     func handle(_ input: Input) {         self.inputSubject.send(input)     }     func work() {         let numbers: [Int] = Array(1...10)         self.cancellable2 = self.inputPublisher.sink { (value) in             let count: Int = .random(in: 3...5)             sleep(UInt32(count))             print(value)         }         self.cancellable = numbers.publisher.receive(on: DispatchQueue.global()).sink { [weak self] (value) in             self?.handle(value)         }     } }

I was overwhelmed by a fact that Apple didn't provide SSLCreateContext for its security APIs. I checked API at Security/SecureTransport.h and it exists. However, it is deprecated. I need a SSLCreateContext function available as C API. Is there any replacement for this function from Network framework?

Hello! I would like to completely hide all buttons in NSAlert ( and also all buttons that can be shown in NSTouchBar ). /// Configure TouchBar /// Configure Alert // Doesn't work alert.window.touchBar = MyCustomTouchBar() alert.runModal() How to do this? Thanks!