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@escaping vs @nonescaping closures
I know this is a frequently asked question, but... After reading many articles on the net, I am still not sure if I have a solid understanding of the logics behind the design. One of my puzzles around this question is - Is the Swift compiler clever enough so that I can solely rely on its warnings/errors?
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772
Jan ’24
FileManager.enumerator and URL problem
I have the following pseudo code: func load(at packageURL: URL) { let realPackageURL = packageURL.resolvingSymlinksInPath() guard let it = fileMan.enumerator(at: realPackageURL) for case let fileURL as URL in it { print(fileURL) // Get filename relative to package root directory let relativeFileName = String(filePath.suffix(filePath.count - packagePath.count)) } } When called with "file:///tmp/some.app", the enumerated fileURL is actually file:///private/tmp/GIMP.app/Contents/ packageURL.resolvingSymlinksInPath() actually does nothing, I assume /tmp is a hard link. This makes it impossible to get a correct relative path. Is there any remedy for this?
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Jan ’24
Reading multi parts of a file concurrently
I have a need to read first half and second half of a file concurrently. Is there any best practices for this scenario? BTW, I did research on DispatchIO but it turned out DispatchIO is all about asynchronous operations on a single file handle; it cannot perform parallel reading. // naive approach Task { fileHandle.read(into:buffer) } Task { // seek to file size / 2 fileHandle.read(into:buffer) }
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1k
Jan ’24
How detect cyclic symbolic links using NSFileManager?
My code is crashing Xcode (or even macOS kernel) during debugging - Xcode just vanishes from screen! // pseudo code public func hunt(in directory: URL) { let fileIterator = fileMan.enumerator(at: directory) // collect app packages into a list var packages = [URL]() for case let fileURL as URL in fileIterator { if fileURL.pathExtension == "app" { packages.append(fileURL) } } // FileWrappers var wrappers = [FileWrappers]() for packageURL in packages { //!!! The line below eventually crashes Xcode (or even macOS kernel once)! wrappers[packageURL] = try? FileWrapper(url: packageURL, options: .immediate) // NOTE: I need FileWrapper.matchesContents later in some code } } // unit test case func test() {} myObj.hunt(in: URL(fileURLWithPath: "/Applications")) } I suspect that the FileWrapper constructor is traversing directories and encounter cyclic symbolic links and eventually it crashes; since it's running at system runtime level, most probably it also crashes macOS kernel! So my question is that is there any way to detect cyclic symbolic links so that I can design my own logics similar to FileWrapper?
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545
Jan ’24
Where is help on Swift documentation markup?
I am reluctant to admit that I only came to know that Swift provides a builtin documentation markup syntax just a few months ago. /** Test func Some description here. - Parameters: - b:Test - d: Test - f: Test - Returns: Bool */ func myMethod(a b:Int, c d:Int, e f:Int) -> Bool { b > d } It seems the markup is pretty simple and has only a few keywords. But, I want to read through the complete reference. Any useful pointers?
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1k
Dec ’23
GridView addRow height problem
I am trying to add rows to GridView and not able to get expected row height correctly. override func viewDidLoad() { super.viewDidLoad() // Remove the row in IB designer gridView.removeRow(at: 0) let image = NSImage(named: NSImage.colorPanelName)! //image.size = NSMakeSize(80, 80) let imageView = NSImageView(image: image) imageView.imageFrameStyle = .grayBezel imageView.imageScaling = .scaleAxesIndependently imageView.frame = NSMakeRect(0, 0, 80, 80) let label = NSTextField(labelWithString: "test text") let row = gridView.addRow(with: [imageView, label]) row.height = 80 } What was wrong with my code?
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904
Dec ’23