by Joachim Bengtsson [email protected]

Tools for abstracting asynchrony in Objective-C. Read the introductory blog entry for much more detail.

System.Threading.Tasks.Task in .Net is very nice. It's a standard library class representing any asynchronous operation that yields a single value. This is deceivingly simple, and gives you much more power of abstraction than you would initially believe.

SPTask is a minimal copy of .Net Task in Objective-C, with functionality to chain multiple asynchronous operations. You can think of it as an extremely lightweight ReactiveCocoa.

An experimental multithreading primitive. The goal is to make every "manager" style class multithreaded with its own work queue, and then make communication between these agents trivial.

Experimental copy of C# 5's "await" keyword, using the preprocessor.

- (SPTask<NSNumber> *)uploadThing:(NSData*)thing
{
    // Variables you want to use need to be declared as __block at the top of the method.
    __block NSData *encrypted, *confirmation;
    
    SPAsyncMethodBegin // Start of an async method, similar to 'async' keyword in C#
    
    // Do work like normal
    [self prepareFor:thing];
    
    // When you make a call to something returning an SPTask, you can wait for its value. The method
    // will actually return at this point, and resume on the next line when the encrypted value is available.
    encrypted = SPAsyncAwait([_encryptor encrypt:thing]);
    
    [_network send:encrypted];
    
    confirmation = SPAsyncAwait([_network read:1]);
    
    // Returning will complete the SPTask, sending this value to all the callbacks registered with it
    return @([confirmation bytes][0] == 0);
    
    SPAsyncMethodEnd
}

In the Extensions folder you'll find extensions to other libraries, making them compatible with SPTask in various ways. You'll have to compile these in on your own when you need them; otherwise they would become dependencies for this library.