tclementdev

libdispatch efficiency tips

The libdispatch is one of the most misused API due to the way it was presented to us when it was introduced and for many years after that, and due to the confusing documentation and API. This page is a compilation of important things to know if you're going to use this library. Many references are available at the end of this document pointing to comments from Apple's very own libdispatch maintainer (Pierre Habouzit).

My take-aways are:

• You should create very few, long-lived, well-defined queues. These queues should be seen as execution contexts in your program (gui, background work, ...) that benefit from executing in parallel. An important thing to note is that if these queues are all active at once, you will get as many threads running. In most apps, you probably do not need to create more than 3 or 4 queues.

• Go serial first, and as you find performance bottle necks, measure why, and if concurrency helps, apply with care, always validating under system pressure. Reuse

Amzd

/// An iOS style TabView that doesn't reset it's childrens navigation stacks when tabs are switched.
public struct UIKitTabView: View {
    private var viewControllers: [UIHostingController<AnyView>]
    private var selectedIndex: Binding<Int>?
    @State private var fallbackSelectedIndex: Int = 0
    
    public init(selectedIndex: Binding<Int>? = nil, @TabBuilder _ views: () -> [Tab]) {
        self.viewControllers = views().map {
            let host = UIHostingController(rootView: $0.view)
            host.tabBarItem = $0.barItem

IanKeen

import SwiftUI

extension View {
    public func discover<T: UIView>(
        tag: Int = .random(in: (.min)...(.max)),
        where predicate: @escaping (T) -> Bool = { _ in true },
        _ closure: @escaping (T) -> Void
    ) -> some View {
        self.overlay(
            DiscoveryView(tag: tag)

timonus

- (UIImage *)dynamicImage
{
    UITraitCollection *const baseTraitCollection = /* an existing trait collection */;
    UITraitCollection *const lightTraitCollection = [UITraitCollection traitCollectionWithTraitsFromCollections:@[baseTraitCollection, [UITraitCollection traitCollectionWithUserInterfaceStyle:UIUserInterfaceStyleLight]]];
    UITraitCollection *const purelyDarkTraitCollection = [UITraitCollection traitCollectionWithUserInterfaceStyle:UIUserInterfaceStyleDark];
    UITraitCollection *const darkTraitCollection = [UITraitCollection traitCollectionWithTraitsFromCollections:@[baseTraitCollection, purelyDarkTraitCollection]];
    
    __block UIImage *lightImage;
    [lightTraitCollection performAsCurrentTraitCollection:^{
        lightImage = /* draw image */;

krzysztofzablocki

#!/bin/zsh

cd "$(dirname "$0")/.."

if [[ -n "$CI" ]] || [[ $1 == "--fail-on-errors" ]] ; then
  FAIL_ON_ERRORS=true
  echo "Running in --fail-on-errors mode"
  ERROR_START=""
  COLOR_END=""
  INFO_START=""

AliSoftware

struct Contact: Decodable, CustomStringConvertible {
    var id: String
    @NestedKey
    var firstname: String
    @NestedKey
    var lastname: String
    @NestedKey
    var address: String

    enum CodingKeys: String, NestableCodingKey {

ole

import Dispatch

@globalActor
final actor MyMainActor {
  // Don’t allow others to create instances
  private init() {}

  // Requirements from the implicit GlobalActor conformance
  typealias ActorType = MyMainActor

atomicbird

/// Log the current filename and function, with an optional extra message. Call this with no arguments to simply print the current file and function. Log messages will include an Emoji selected from a list in the function, based on the hash of the filename, to make it easier to see which file a message comes from.
/// - Parameter message: Optional message to include
///   - file: Don't use; Swift will fill in the file name
///   - function: Don't use, Swift will fill in the function name
///   - line: Don't use, Swift will fill in the line number
func logMilestone(_ message: String? = nil, file: String = #file, function: String = #function, line: Int = #line) -> Void {
    #if DEBUG
    // Feel free to change the list of Emojis, but don't make it shorter, because a longer list is better.
    let logEmojis = ["😀","😎","😱","😈","👺","👽","👾","🤖","🎃","👍","👁","🧠","🎒","🧤","🐶","🐱","🐭","🐹","🦊","🐻","🐨","🐵","🦄","🦋","🌈","🔥","💥","⭐️","🍉","🥝","🌽","🍔","🍿","🎹","🎁","❤️","🧡","💛","💚","💙","💜","🔔"]
    let logEmoji = logEmojis[abs(

Amzd

/// Fixed swipe gesture NavigationLink
struct NavigationLink<Destination: View, Label:View>: View {
    var destination: Destination
    var label: () -> Label
    
    public init(destination: Destination, @ViewBuilder label: @escaping () -> Label) {
        self.destination = destination
        self.label = label
    }
    

matej

//
//  CALayer+MBAnimationPersistence.h
//
//  Created by Matej Bukovinski on 19. 03. 14.
//  Copyright (c) 2014 Matej Bukovinski. All rights reserved.
//

#import <QuartzCore/QuartzCore.h>