griffin-stewie griffin-stewie

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

	import UIKit

	#if canImport(SwiftUI) && DEBUG
	import SwiftUI
	struct UIViewControllerPreview<ViewController: UIViewController>: UIViewControllerRepresentable {
	let viewController: ViewController

	init(_ builder: @escaping () -> ViewController) {
	viewController = builder()
	}

	import AppKit
	import ScriptingBridge

	@objc public protocol SBObjectProtocol: NSObjectProtocol {
	func get() -> Any!
	}

	@objc public protocol SBApplicationProtocol: SBObjectProtocol {
	func activate()
	var delegate: SBApplicationDelegate! { get set }

	import Foundation

	extension Character {
	var isEmoji: Bool {
	return unicodeScalars.allSatisfy { $0.properties.isEmoji }
	}
	}

	func recentlyUsedEmoji() -> [Character]? {
	#if os(iOS)

	struct LazyView<Content: View>: View {
	let build: () -> Content
	init(_ build: @autoclosure @escaping () -> Content) {
	self.build = build
	}
	var body: Content {
	build()
	}
	}

	//
	// MobileProvision.swift
	// Fluux.io
	//
	// Created by Mickaël Rémond on 03/11/2018.
	// Copyright © 2018 ProcessOne.
	// Distributed under Apache License v2
	//

	import Foundation

griffin-stewie griffin-stewie

libdispatch efficiency tips

Helix キーボードキットの製作に必要な工具メモ

目次

	import UIKit

	/// A validation rule for text input.
	public enum TextValidationRule {
	/// Any input is valid, including an empty string.
	case noRestriction
	/// The input must not be empty.
	case nonEmpty
	/// The enitre input must match a regular expression. A matching substring is not enough.
	case regularExpression(NSRegularExpression)

	#!/usr/bin/env bash

	set -e

	VOLUME_PATH=/Volumes/installer
	while getopts ":d:h" opts; do
	case $opts in
	d)
	VOLUME_PATH=$OPTARG
	;;

	#!/bin/bash

	UUID_REGEX='s/^.\([0-9A-Z]\{8\}-[0-9A-Z]\{4\}-[0-9A-Z]\{4\}-[0-9A-Z]\{4\}-[0-9A-Z]\{12\}\).$/\1/p'

	xcrun simctl shutdown all
	xcrun simctl delete unavailable
	xcrun simctl list devices \| sed -n $UUID_REGEX \| xargs -I {} xcrun simctl erase "{}"
	xcrun simctl list devices \| sed -n $UUID_REGEX \| xargs -I {} xcrun simctl delete "{}"
	rm -fr "$HOME"/Library/Developer/CoreSimulator/Devices/*