const app = {
lines: document.getElementById('lines'),
textbox: createTextbox(),
lineTemplate: createLineTemplate(),
}

const socket = connect(
`ws://${location.host}/app`,
{

initial({ lines, uuid, charLimit }) {
app.uuid = uuid
app.charLimit = charLimit
lines.forEach(addLine)
},

added(line) {
addLine(line)
},

removed(i) {
app.lines.children[i].remove()
},

server.onclose = (ws) => {
if (ws.line) {
const i = lines.indexOf(ws.line)
lines.splice(i, 1)
server.sendToAll({ removed: i })
}
}

server.commands = {

begin(ws) {
const line = {
hash: ws.hash,
uuid: ws.uuid,
text: '',
}

ws.line = line
lines.push(line)
server.sendToAll({ added: line })
},

run() {
console.log(`Running on port ${this.port}`)

this.wss = new WebSocket.Server({
port: this.port,
verifyClient: this.verify.bind(this)
})

setInterval(
this.prune.bind(this),
this.pruneInterval * 1000
)

this.wss.on(
'connection',
this.connection.bind(this)
)
}

Steven Degutis

Full-stack software developer for hire

Actual Runtime Classes

February 24, 2009 — 8 years ago
Note: This article was written 8 years ago. It may refer to files or websites lost to the ages. It may advocate outdated practices. Take it with a grain of salt.

I have this fascination with the Objective-C runtime that I don't know if I'll ever be able to explain. So, the other day I wrote some code that printed out all of the Objective-C runtime in a nice, hierarchically organized indented outline.

Later, I decided I could do even better, and explore NSBrowser a bit more in the process. So I came up with this nifty little program, PrivateEye Lite, that lets you explore the runtime system. Download it, try it out, you might find it actually answers a few questions you had.

PrivateEye Lite window, with inspector tables below

Anyway, I decided I would share a bit about how I actually made this. I'll explain more about the actual runtime system in a tutorial in the near future, but for now, here are the two methods I used to generate the entire hierarchy of classes:

- (id) init {
	if (self = [super init]) {
		int count = objc_getClassList(NULL, 0);
		Class *classes = malloc(sizeof(Class) * count);
		objc_getClassList(classes, count);

		rootClasses = [self arrayOfClassesWithSuperclass:Nil inArray:classes count:count indentation:0];
		[rootClasses retain];

		free(classes);

		//[NSApp terminate:self];
	}
	return self;
}

- (NSMutableArray*) arrayOfClassesWithSuperclass:(Class)superclass inArray:(Class*)classes count:(int)count indentation:(int)indent {
	NSMutableArray *classList = [NSMutableArray array];

	int i;
	for (i = 0; i < count; i++) {
		Class class = classes[i];

		if (class_getSuperclass(class) == superclass) {
			NSMutableArray *subclasses = [self arrayOfClassesWithSuperclass:class inArray:classes count:count indentation:(indent + 4)];
			NSString *className = [NSString stringWithCString:class_getName(class) encoding:NSUTF8StringEncoding];

			SDClassNode *classNode = [[[SDClassNode alloc] initWithClassName:className subclasses:subclasses] autorelease];

			[classList addObject:classNode];
		}
	}

	NSSortDescriptor *sortDescriptor = [[[NSSortDescriptor alloc] initWithKey:@"className" ascending:YES selector:@selector(compare:)] autorelease];
	[classList sortUsingDescriptors:[NSArray arrayWithObject:sortDescriptor]];
	return classList;
}

It doesn't contain any UI code or anything regarding the "inspector" section of the code (the four tables at the bottom). It just shows how I created a hierarchy using recursion and C functions.

At first, objc_getClassList() is used twice. This may seem odd or confusing to some people. Yes, it is a little weird, but not very weird if you consider that this is C, not Objective-C, that we are dealing with. It is a lot less dynamic and introspective. So, we call objc_getClassList() the first time to get the size (count) of the array, create the array with the proper size we just obtained, and then call objc_getClassList() a second time to fill the array. After we're all done, a few lines down, we release the memory used by the array, as we're done with it, via free().

Update: 8 years later, I look back at this article and realize I was wrong. We're supposed to use both the pointer and the count from the single call to objc_getClassList() to know how many entries it has and to free it, all in one call. Calling it twice was just a waste.

Notice that the -arrayOfClassesWithSuperclass:inArray:count:indentation: method takes two arguments, a C array and a count method. Again, this is because C arrays are not as dynamic and encapsulated as Objective-C arrays, so the only other way to determine the count is to have a NULL terminator. The function's documentation does not state anywhere that its returned array contains such a terminator, so we assume it does not. (In reality, it might, but that would just be a coincidence.)

The recursive function looks scary at first, but it actually only does what it states. It returns an subarray of classes (from the passed array of all classes) whose superclass is the one in the first argument. This is pretty easy, we just loop through the array, call class_getSuperclass() on the enumerated classes, and if they match the argument "superclass," then we add it to the array which we return when we're done.

(The indentation argument isn't really relevant in the application's context anymore; it was used back when the application initially printed the outlined list out.)

So, that's it! Inspecting the Objective-C's runtime is really as easy as calling a few C functions. Just make sure to pay attention to your memory usage, and not do crashy things like fill an un-initialized C array with anything!

Also, I noticed that there is a private subclass of NSBox called NSStopTouchingMeBox — what in the world is this? It takes two siblings and moves them around, as far as I can tell. And it seems to have been around for nearly a decade now, if not longer. Just wondering, if anyone has any idea, because it's so strange that it's intriguing!

About me

My name is Steven Degutis, and I've been writing software professionally for almost a decade. During that time, I've written many apps and websites, quite a few techical articles, and kept up-to-date with the rapidly evolving software industry.

If you have software needs for web, mobile, or desktop, and are looking for a seasoned software professional, please reach out to me at sbdegutis@gmail.com to set up a phone call.

Work Experience

  • Self-employed – present
  • Clean Coders – 5 years
  • 8th Light – 2 years
  • Big Nerd Ranch – 1 year
  • Self-employed - 1 year

Platforms

  • Web: full-stack
  • iOS (UIKit)
  • macOS (Cocoa)
  • REST APIs
  • AWS / EC2 / ELB

Languages

  • JavaScript
  • HTML5 / CSS
  • Swift
  • Objective-C
  • Clojure

Frameworks

  • Node.js
  • Express.js
  • React
  • Vue.js
  • Electron

Technical articles

Over the past decade, I've written a total of 169 technical articles on various programming languages, frameworks, best practices, and my own projects, as I kept up-to-date and active in the software industry.

Subscribe via RSS / Atom.

Chronological

Portfolio

Here are some of the projects I'm most proud of. They were created using a variety of technologies, running on several different platforms and OSes. They're all finished products, and many of them are open source.

CleanCoders.com

Website - Online Video Store

I wrote this web store for Robert "Uncle Bob" Martin, using Clojure for the back-end, and JavaScript for the front-end. Over the course of 5 years, I took the site from a simple three-page website to a full enterprise-ready business solution, with nearly 100% test coverage.

  • Clojure
  • Datomic
  • jQuery / D3.js
  • JavaScript
  • ClojureScript

Docks

macOS app - Dock Utility

I made Docks in 2009 for users who wanted to swap out icons in their Dock with a single click. Its unique functionality and design aesthetic attracted the attention of Apple, Engadget, MacWorld, and led to an acquisition of my start-up by Big Nerd Ranch.

  • Apple.com Staff Pick
  • MacWorld 4/5 Rating
  • MacWorld Gem of the Year
  • Featured on Engadget.com

Leviathan

macOS app - Clojure IDE

Source Code

While working on CleanCoders.com, a website written completely in Clojure, I increased my productivity by building a custom IDE for macOS designed specifically for Clojure projects.

  • Objective-C
  • Clojure
  • C / C++
  • Cocoa
  • Themeable

Zephyros

macOS app - Hackable Automation

Source Code

This began as an experiment to see how many languages I could use to script a custom macOS window manager using our custom TCP protocol. Eventually it had bindings for Clojure, Ruby, Python, Go, JavaScript, CoffeeScript, Node.js, Chicken Sceme, and Racket, as well as other community additions.

  • TCP / Unix sockets
  • Custom protocol
  • Highly Scriptable
  • 10+ language bindings
  • Open source community

Bubble Maker

iOS app - Bubble simulator

This toy was made in a weekend to entertain my 1 year old daughter. It lets you create bubbles with your fingers, which then simulate physics by bumping into each other and falling.

  • SpirteKit
  • Custom art
  • Physics simulation
  • iOS
  • tvOS

Quick List

iOS app - Todo list app

When I couldn't find an app in the App Store that let me make very simple lists extremely quickly, I made one myself. I use it almost every day to organize and track my activities.

  • In-app purchases
  • Custom UI / UX
  • Social media
  • App Store artwork
  • Spring animations

sdegutis.com

Website - Personal Portfolio

Source Code

This very site itself was written from scratch in about a day. It uses best practices for modern responsive web design, and a custom build phase to compile the sources into a single HTML file.

  • Node.js
  • Pug / Jade
  • LessCSS
  • HTML5
  • WebSockets

2048

Java app - Game

Source Code

The game 2048 (created by Gabriele Cirulli) is so fun that my kids wanted their own copy. So I wrote this version in Java 8, using JavaFx for attractive graphics and silky smooth animations.

  • Java 8
  • JavaFx
  • Modular code
  • Customizable
  • Animations

Mjolnir

macOS app - Window Manager

Source Code

I created this app to increase my productivity by letting me move windows around in macOS using keyboard shortcuts. It grew into a community-driven highly extensible app, using Lua for its plugin system.

  • Objective-C
  • Embedded Lua
  • Plugin system
  • Fully documented
  • 5,000 GitHub stars

AffluentConfidante.com

Website - Social Network

Implementing this elite social network gave me experience integrating both Apple Pay and credit card payments (via Stripe.com) seamlessly into web apps, for a frictionless and pain-free payment experience.

  • Clojure
  • Elastic Beanstalk
  • PostgreSQL
  • Stripe.com
  • Apple Pay

HyperChat

Website - Live Chatroom

Source Code

This isn't just any chatroom. In this web app, you can see what everyone is typing while they type it. I made this in order to scratch my itch for making real-time apps and games, and learned how to use WebSockets in the process.

  • JavaScript
  • WebSockets
  • Node.js
  • Vue.js
  • CSS

Bahamut

macOS app - Music Player

Source Code

As iTunes went through many user interface changes, I wanted an app that was consistent, intuitive, and easy to use. So I created Bahamut, a minimal music player for macOS with a custom user interface.

  • Objective-C
  • Custom UI
  • Cocoa
  • Core Data
  • AVFoundation

Chatter

macOS app - Chat (IRC) Client

Source Code

This was written in 2009, before the time of Slack, when IRC was the main way for programmers to get short-term assistance from each other. Its purpose was to be a beautiful app with an emphasis on simplicity and usability over technical power.

  • Async networking
  • Core Animation
  • Core Text
  • IRC Protocol
  • UI Design

AppGrid

macOS app - Window Manager

Source Code

This is an app I actually use every single day. It lets you move windows with global keyboard shortcuts. Since it uses Vim-like key bindings, it should feel pretty natural to any programmer. There's no configuration needed; it Just Works™.

  • Minimalist UI
  • Simple UI
  • Vim-like Hotkeys
  • Global Hotkeys
  • Zero-configuration

Hydra

macOS app - Lua window manager

Source Code

As an evolution of Phoenix, Hydra was my first attempt at embedding a full Lua virtual machine into an Objective-C app, to make a lightweight and efficient window manager that focused on speed, low memory usage, low CPU usage, and overall being gentle on laptop batteries.

  • Embedded Lua
  • Generated docs
  • Lightweight
  • Memory efficient
  • CPU efficient

Phoenix

macOS app - JavaScript window manager

Source Code

As an evolution of Zephyros, Phoenix was my attempt to use Cocoa's native JavaScript bindings to make a more lightweight and efficient window manager, that focused on speed, low memory usage, low CPU usage, and overall being gentle on laptop batteries.

  • JavaScriptCore
  • JavaScript API
  • Lightweight
  • Memory efficient
  • CPU efficient

Smaller projects

These may be tiny, but they're interesting technical feats.

Lua4SwiftSwift framework for embedding Lua with a native Swift API.
chooseCommand line fuzzy-matching tool for macOS that uses a GUI
musicCommand line music daemon for macOS that only speaks JSON
hectoCommand line text editor with an embedded Lua plugin system
ZephSharpWindow manager for Windows using Clojure for scripting
managementMinimalist EC2 configuration & deployment tool in Ruby.
go.assertAssertion helper package for writing tests in Go.
go.shattrGo library for printing shell-attributed strings to stdout.
OCDSpec2Objective-C based testing framework with Xcode integration.