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Is it safe to call low level Darwin function on FileHandle?
I have the following code: extension FileHandle { func readInto(_ buffer: inout [UInt8]) -> Int { buffer.withUnsafeMutableBytes { Darwin.read(fileDescriptor, $0.baseAddress, $0.count) } } } It can compile, but I wonder if this is supported since it's code in an app that is going to be submitted to App Store. The reason I don't use read(upToCount:) or readData(ofLength:) is that I am reading possibly very large files by small chunks and don't want to let Swift runtime allocate small buffers repeatedly.
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244
Nov ’23
Data(contentsOf:) with huge file
I have a function that computes MD5 hash of a file: func ComputeMD5(ofFile path: String) -> [UInt8]? { if let data = try? Data(contentsOf: URL(fileURLWithPath: path)) { var digest = [UInt8](repeating: 0, count: 16) data.withUnsafeBytes { _ = CC_MD5($0.baseAddress, UInt32(data.count), &digest) } return digest } return nil } Now I wonder/worry what happens if the file is very huge. Does the runtime perform disk memory paging?
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Nov ’23
PropertyListDecoder and .strings file
I have the following code: let file = "/path/to/en.lproj/Localizable.strings" let dec = PropertyListDecoder() var f: PropertyListSerialization.PropertyListFormat = .openStep do { //let data = strings.data(using: .utf8)! let data = try Data(contentsOf: URL(fileURLWithPath: file)) let list = try dec.decode([String: String].self, from: data, format: &f) print("foramt:", f.rawValue) list.forEach { print($0.key, $0.value) } } catch { print(error) } It seems PropertyListDecoder can correctly decode .strings file format; detected format is openStep (value is 1). But I am note sure because I couldn't find any docs on PropertyListDecoder about .strings file. Can anyone confirm this?
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341
Oct ’23
Weird error with HTTPS connection
I have a weird problem with HTTPS connection. Task <A19A5441-F5CD-4F8C-8C88-73FC679D8AE0>.<1> finished with error [-1200] Error Domain=NSURLErrorDomain Code=-1200 "An SSL error has occurred and a secure connection to the server cannot be made." I am trying to bypass server certificate of my website because it's self-signed. The following code works in a test app, but not in another app. They have exactly have the same entitlements: <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"> <plist version="1.0"> <dict> <key>com.apple.security.app-sandbox</key> <true/> <key>com.apple.security.files.user-selected.read-write</key> <true/> <key>com.apple.security.network.client</key> <true/> </dict> </plist> func urlSession(_ session: URLSession, didReceive challenge: URLAuthenticationChallenge, completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void) { let protectionSpace = challenge.protectionSpace guard protectionSpace.authenticationMethod == NSURLAuthenticationMethodServerTrust, protectionSpace.host.contains("mywebsite.net") else { completionHandler(.performDefaultHandling, nil) return } guard let serverTrust = protectionSpace.serverTrust else { completionHandler(.performDefaultHandling, nil) return } let credential = URLCredential(trust: serverTrust) completionHandler(.useCredential, credential) } @IBAction func testMenuItem_select(_ sender: Any) { print("\(sender)") Preferences.instance.openTipShowed = false testURLSession() func testURLSession() { let session = URLSession(configuration: URLSessionConfiguration.ephemeral, delegate: self, delegateQueue: nil) let url2 = "https://www.mywebsite.net/spiders.txt" let url3 = "https://www.apple.com/" let url = URL(string: url2)! var request = URLRequest(url: url) let task = session.dataTask(with: request) { data, response, error in if let error { print(error) } if let data { let text = String(data: data, encoding: .utf8) print("HTTP response object:", response ?? "") print("HTTP resonse text:", text ?? "<empty response>") } } task.resume() } }
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Oct ’23
Need help on generics where clause
I have the following class: /// Act as a reference container for value types. public class ValueBox<ValueType: ??> { public var value: ValueType public init() { value = ValueType() // Compiler error } public init(_ value: ValueType) { self.value = value } } Is it possible to specify the generic type ValueType can be inited?
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230
Oct ’23
Need help on Array and API design
I am working on an app which I plan to submit to App Store in 2 weeks. Now I have a headache with Array type. I have the following API design in my app: class SomeParser { func getTranslations(_ locale: String) -> [TranslationUnit]? { // Check if the locale units are already in a cache, if not build a new list // and return the list } } class MainVC { func doTranslation() { var list = parser.getTranslation("en") // Modify some units in the list. // How to put it back to cache? } } Now the problem is that since Array is a value type, the modified list is isolated. The only way to reflect the changes into cache is put the modified list back to cache: translationCache[locale] = modifiedList But this is counter-intuitive and waste of performance. Is there anyway to workaround this problem?
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318
Oct ’23
Any way to get array by reference?
Today I spent one hour to get myself educated on Array type. I have the following class in one of my app: class PathNode: Hashable, Comparable, CustomStringConvertible { var name: String! var path: String! var children: [PathNode]? static func == (lhs: PathNode, rhs: PathNode) -> Bool { lhs.name == rhs.name } static func < (lhs: PathNode, rhs: PathNode) -> Bool { lhs.name < rhs.name } func hash(into hasher: inout Hasher) { hasher.combine(name) hasher.combine(children) } /// Sort child nodes. func sort() { if let children = self.children { children.sort() for child in children { child.sort() } } } // other members... } The problem is in the sort function. I found out in my outline view the result is not sorted even though I did call sort on the root node. After about one hour's frustration, I came to realize that I forgot one import fact about the array type in Swift - it's a value type! I have to adjust sort function to the following code: /// Sort child nodes. func sort() { if self.children != nil { self.children!.sort() for child in self.children! { child.sort() } } } That's not an elegant way of writing code! Is there any other way to get a 'reference' to an array in Swift?
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334
Sep ’23
Symbol navigator is polluted with thousands of system classes!
I have a test app. I added some extension classes to one of source code like below: extension String { func addPathComponent(_ path: String) -> String { return (self as NSString).appendingPathComponent(path) } func sameText(with: String) -> Bool { return self.caseInsensitiveCompare(with) == .orderedSame } var isBlank: Bool { allSatisfy { $0.isWhitespace } } } extension Optional where Wrapped == String { var isBlank: Bool { self?.isBlank ?? true } } Now the symbol navigator is polluted with many system classes: BTW, I am using Xcode 14.3.1.
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461
Sep ’23