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//
// main.swift
// Shell Notification Center
//
// Created by Keng Lee on 2021/1/15.
//
import Foundation
import Combine
var bag = Set<AnyCancellable>()
@rollwagen
rollwagen / ESXi.md
Last active September 6, 2024 13:01
ESXi links, info, one-liners etc

esxi (on mac mini)

prepare USB boot install drive

adding a USB datastore

Disable:

sudo launchctl unload -w /System/Library/LaunchDaemons/com.apple.metadata.mds.plist

Enable:

sudo launchctl load -w /System/Library/LaunchDaemons/com.apple.metadata.mds.plist

@tclementdev
tclementdev / libdispatch-efficiency-tips.md
Last active November 10, 2025 03:11
Making efficient use of the libdispatch (GCD)

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

@karwa
karwa / codablebridge.swift
Created November 1, 2017 04:57
codable-nscoding bridge
import Foundation
/// This isn't safe to use before Swift gets ABI stability, because generic classes
/// could change their names. Also, be sure to register bridges with the Obj-C runtime
/// if using to decode during iOS state restoration.
///
class CodableBridge<Wrapped: Codable>: NSObject, NSSecureCoding {
let value: Wrapped
init(_ value: Wrapped) { self.value = value }
@steipete
steipete / SpinlockTestTests.swift
Last active January 20, 2025 15:55 — forked from RomanTruba/Synchronization_test_iOS_SDK10
Updated for Xcode 8, Swift 3; added os_unfair_lock
//
// SpinlockTestTests.swift
// SpinlockTestTests
//
// Created by Peter Steinberger on 04/10/2016.
// Copyright © 2016 PSPDFKit GmbH. All rights reserved.
//
import XCTest
@defHLT
defHLT / gist:6b68dd358b7b57ca71f1
Created July 5, 2015 18:55
Sqlite Mandelbrot
-> ice ~ % sqlite3
SQLite version 3.8.6 2014-08-15 11:46:33
Enter ".help" for usage hints.
Connected to a transient in-memory database.
Use ".open FILENAME" to reopen on a persistent database.
sqlite>
WITH RECURSIVE xaxis(x) AS (VALUES(-2.0) UNION ALL SELECT x+0.05 FROM xaxis WHERE x<1.2), yaxis(y) AS (VALUES(-1.0) UNION ALL SELECT y+0.1 FROM yaxis WHERE y<1.0), m(iter, cx, cy, x, y) AS ( SELECT 0, x, y, 0.0, 0.0 FROM xaxis, yaxis UNION ALL SELECT iter+1, cx, cy, x*x-y*y + cx, 2.0*x*y + cy FROM m WHERE (x*x + y*y) < 4.0 AND iter<28 ), m2(iter, cx, cy) AS ( SELECT max(iter), cx, cy FROM m GROUP BY cx, cy ), a(t) AS ( SELECT group_concat( substr(' .+*#', 1+min(iter/7,4), 1), '') FROM m2 GROUP BY cy ) SELECT group_concat(rtrim(t),x'0a') FROM a;
sqlite> ....#
..#*..
..+####+.