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

ryanflorence

Turning Off Github Issues

My friend Michael Jackson turned off github issues on one of his smaller projects. It got me thinking...

Maintainers getting burned out is a problem. Not just for the users of a project but the mental health of the maintainer. It's a big deal for both parties. Consumers want great tools, maintainers want to create them, but maintainers don't want to be L1 tech support, that's why they

dornad

- (void)testMethodExpectingNoError
{
  id someObject = [self someMethodThatReturnsAnExpectedObject]; 
  id mockDependencuy = OCMClassMock([DependencyToBeMocked class]);
  OCMStub([mockDependency someMethodWithErrorRef:[OCMArg anyObjectRef]).andReturn(someObject);
  
  NSError * error = nil;
  id someReturnedValue =[self.objectUnderTest someMethodWithErrorRef:&error]:
  
  XCTAssertNotNil(someReturnedValue);

hooman

// The correct implementation of `Equatable` (and `Comparable`) can be tricky for class
// hierarchies. To make it easier, it is better to follow a well-defined pattern. Here
// is my suggestion on how to do it:

// 1. Define a protocol for polymorphic test function for equality (or comparison): 
// Note: operators are not polymorphic (not virtual in C++ terms)). The function to 
// call is determined and hard-coded at compile time.

/// A protocol to ammend `Equatable` for use with `class` types.

gamenerds

#import <Foundation/Foundation.h>

// This helps deal with NSPointerArray that stores pointers to objects that inherit from NSObject.
// Not sure if this will work for other pointer types!!
@interface NSPointerArray (Helpers)

/**
 *  Adds pointer to the given object to the array.
 *
 *  @param object Object whose pointer needs to be added to the array. 

staltz

The introduction to Reactive Programming you've been missing

(by @andrestaltz)

---

This tutorial as a series of videos

If you prefer to watch video tutorials with live-coding, then check out this series I recorded with the same contents as in this article: Egghead.io - Introduction to Reactive Programming.

---

adaugherity

#!/usr/bin/ruby
# Create display override file to force Mac OS X to use RGB mode for Display
# see http://embdev.net/topic/284710

require 'base64'

data=`ioreg -l -d0 -w 0 -r -c AppleDisplay`

edids=data.scan(/IODisplayEDID.*?<([a-z0-9]+)>/i).flatten
vendorids=data.scan(/DisplayVendorID.*?([0-9]+)/i).flatten

steipete

NSUInteger PSPDFHashFromCGRect(CGRect rect) {
    return (*(NSUInteger *)&rect.origin.x << 10 ^ *(NSUInteger *)&rect.origin.y) + (*(NSUInteger *)&rect.size.width << 10 ^ *(NSUInteger *)&rect.size.height);
}

steipete

// Taken from the commercial iOS PDF framework http://pspdfkit.com.
// Copyright (c) 2014 Peter Steinberger, PSPDFKit GmbH. All rights reserved.
// Licensed under MIT (http://opensource.org/licenses/MIT)
//
// You should only use this in debug builds. It doesn't use private API, but I wouldn't ship it.

// PLEASE DUPE rdar://27192338 (https://openradar.appspot.com/27192338) if you would like to see this in UIKit.

#import <objc/runtime.h>
#import <objc/message.h>

dergachev

OS X Screencast to animated GIF

This gist shows how to create a GIF screencast using only free OS X tools: QuickTime, ffmpeg, and gifsicle.

Instructions

To capture the video (filesize: 19MB), using the free "QuickTime Player" application: