MartinP7r

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

MartinP7r

class GoogleSignInService: NSObject, SignInService, GIDSignInDelegate, GIDSignInUIDelegate {

    // intermediary closure to be called when sign-in finishes
    var signedIn: ((String) -> Void)?

    func setup() { /* (...) */ }

    func signIn(_ completion: @escaping (String) -> Void) {

        // hand own completion block to intermediary closure

MartinP7r

// Starts the sign-in process.  The delegate will be called at the end of this process.  
// (...)
- (void)signIn;

// The sign-in flow has finished and was successful if |error| is |nil|.
- (void)signIn:(GIDSignIn *)signIn
    didSignInForUser:(GIDGoogleUser *)user
           withError:(NSError *)error;

MartinP7r

class Authenticator {

    let userDataService = UserDataService()

    func auth(using signInService: SignInService,
              _ completion: @escaping (_ user: User?) -> Void) {

        signInService.signIn { token in
            userDataService.load(forToken: token) { user in
                completion(user)   // note: error handling omitted for brevity

MartinP7r

class SomeSignInService: SignInService {

    init() {
        // do whatever the provider needs to be set up
    }

    func signIn(_ completion: @escaping (String?) -> Void) {
        // call the sign in service and receive a token
        completion(token)
    }

MartinP7r

protocol SignInService {
    func signIn(_ completion: @escaping (_ id: String?) -> Void)
    func signOut()
}

MartinP7r

{"lastUpload":"2021-10-30T05:17:01.742Z","extensionVersion":"v3.4.3"}

MartinP7r

'+-------------------------------------+
'| @author: Martin Pfundmair           |
'| @version: 1.0                       |
'| @date: 2014-05-31                   |
'|                                     |
'| $cript:                             |
'| creates shortcuts in ShortcutFolder |
'| for all Application files (*.exe)   |
'| in all level-1 subfolders of the    |
'| specified target folders            |

MartinP7r

'source: http://techniclee.wordpress.com/2010/07/21/isletter-function-for-vba/
Function IsLetter(strValue As String) As Boolean
    Dim intPos As Integer
    For intPos = 1 To Len(strValue)
        Select Case Asc(Mid(strValue, intPos, 1))
            Case 65 To 90, 97 To 122
                IsLetter = True
            Case Else
                IsLetter = False
                Exit For

MartinP7r

package exchangeRateApp;

import java.io.InputStream;
import java.math.BigDecimal;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;

import javax.swing.text.html.HTMLDocument.HTMLReader.IsindexAction;
import javax.xml.parsers.DocumentBuilder;