Ilya Grechuhin igrechuhin

libdispatch efficiency tips

I suspect most developers are using the libdispatch inefficiently due to the way it was presented to us at the time it was introduced and for many years after that, and due to the confusing documentation and API. I realized this after reading the 'concurrency' discussion on the swift-evolution mailing-list, in particular the messages from Pierre Habouzit (who is the libdispatch maintainer at Apple) are quite enlightening (and you can also find many tweets from him on the subject).

My take-aways are:

Class currentClass = [NSClassFromString(@"ClassName") class];
while (currentClass) {
    // Iterate over all instance methods for this class
    unsigned int methodCount;
    Method *methodList = class_copyMethodList(currentClass, &methodCount);

    unsigned int i = 0;
    for (; i < methodCount; i++) {

NSLog(@"%@ - %@", [NSString stringWithCString:class_getName(currentClass) encoding:NSUTF8StringEncoding], [NSString stringWithCString:sel_getName(method_getName(methodList[i])) encoding:NSUTF8StringEncoding]);

	final class DebugPrinter {
	private var address2Name: [UnsafeMutableRawPointer: String] = [:]
	private var typeIndex: [String: Int] = [:]
	private let marker: String

	private let formatter: DateFormatter = {
	let formatter = DateFormatter()
	formatter.dateFormat = "HH:mm:ss.SSS"
	return formatter
	}()

	######################
	# Options
	######################

	REVEAL_ARCHIVE_IN_FINDER=false

	FRAMEWORK_NAME="${PROJECT_NAME}"

	SIMULATOR_LIBRARY_PATH="${BUILD_DIR}/${CONFIGURATION}-iphonesimulator/${FRAMEWORK_NAME}.framework"

	func getUIImageForRGBAData(#width: UInt, #height: UInt, #data: NSData) -> UIImage? {
	let pixelData = data.bytes
	let bytesPerPixel:UInt = 4
	let scanWidth = bytesPerPixel * width

	let provider = CGDataProviderCreateWithData(nil, pixelData, height * scanWidth, nil)

	let colorSpaceRef = CGColorSpaceCreateDeviceRGB()
	var bitmapInfo:CGBitmapInfo = .ByteOrderDefault;
	bitmapInfo \|= CGBitmapInfo(CGImageAlphaInfo.Last.rawValue)

	Swift:

	extension UIWindow {

	func visibleViewController() -> UIViewController? {
	if let rootViewController: UIViewController = self.rootViewController {
	return UIWindow.getVisibleViewControllerFrom(rootViewController)
	}
	return nil
	}