jspahrsummers

/// Observes a run loop to detect any stalling or blocking that occurs.
///
/// This class is thread-safe.
@interface GHRunLoopWatchdog : NSObject

/// Initializes the receiver to watch the specified run loop, using a default
/// stalling threshold.
- (id)initWithRunLoop:(CFRunLoopRef)runLoop;

/// Initializes the receiver to detect when the specified run loop blocks for

andymatuschak

//
//  MultiDirectionAdjudicatingScrollView.swift
//  Khan Academy
//
//  Created by Andy Matuschak on 12/16/14.
//  Copyright (c) 2014 Khan Academy. All rights reserved.
//

import UIKit
import UIKit.UIGestureRecognizerSubclass

steipete

            // This ensures that the automaticallyAdjustsScrollViewInsets magic works
            // On our newly added view controller as well.
            // This triggers _layoutViewController which then triggers
            // _computeAndApplyScrollContentInsetDeltaForViewController:
            // which finally updates our content inset of the scroll view (if any)
            // rdar://19053416
            [self.navigationController.view setNeedsLayout];

mbbischoff

//
//  LCKIndexedFetchedResultsController.h
//  Quotebook
//
//  Created by Andrew Harrison on 7/26/14.
//  Copyright (c) 2014 Lickability. All rights reserved.
//

@import CoreData;

steipete

BOOL PSPDFSystemFunctionOverriddenInCategory(Class theClass, SEL selector, NSString *__autoreleasing* categoryName) {
    NSCParameterAssert(theClass);
    NSCParameterAssert(selector);

    Dl_info info;
    if (dladdr(class_getMethodImplementation(theClass, selector), &info)) {
        // /System/Library/Frameworks is a common denominator, some methods are in /usr/lib/libobjc.A.dylib
        // Custom app is in /private/var/mobile/Containers/Bundle/Application/<UID>/PSPDFCatalog.app/PSPDFCatalog
        if (!strstr(info.dli_fname, "/System/Library") && !strstr(info.dli_fname, "/usr/lib")) {
            if (categoryName) *categoryName = @(info.dli_sname);

jspahrsummers

	Hot	Cold	Notes
Behaviors	Always		Property values over time
Events	Maybe	Maybe	This is a design decision, but picking “hot” requires introducing some concept of buffering
Promises	Sorta	Sorta	Promises don't do work until started, but only do it once, and share/buffer their result

neonichu

import Foundation
import ObjectiveC.runtime

let myString = "foobar" as NSString

println(myString.description)

let myBlock : @objc_block (AnyObject!) -> String = { (sself : AnyObject!) -> (String) in
    "✋"
}

nicklockwood

Suppose we want to add support for a new iOS 8 API in our framework that replaces an older iOS 7 API. There are a few problems we might face:

1. The new API will crash if we call it on iOS 7
2. The new API won't compile if we build it using the iOS 7 SDK
3. The old API will raise a deprecation warning if built with a deployment target of iOS 8 and up

These three problems require three different technical solutions:

1. We can avoid calling the new API on an old OS version by using runtime detection (e.g. respondsToSelector:)
2. We can avoid compiling new APIs on old SDKs using the __IPHONE_OS_VERSION_MAX_ALLOWED macro

hooman

// Playground - noun: a place where people can play
//
//
//    By: Hooman Mehr ([email protected])
//  Gist: https://gist.github.com/hooman/599e381d5f037b87d20b (The latest version is always here)
//
//
// Update:  07/30/2014
//          Added WeaklyOwned & removeOrphans for memory management support, added more generics & basic access control.
//          08/06/2014

mattt

@import MobileCoreServices;

static CFStringRef UTTypeForImageData(NSData *data) {
    const unsigned char * bytes = [data bytes];

    if (data.length >= 8) {
        if (bytes[0] == 0x89 && bytes[1] == 0x50 && bytes[2] == 0x4E && bytes[3] == 0x47 && bytes[4] == 0x0D && bytes[5] == 0x0A && bytes[6] == 0x1A && bytes[7] == 0x0A) {
            return kUTTypePNG;
        }
    }