swift-async 0.1.0

swift-async 0.1.0

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TestsTested ✗
LangLanguage Obj-CObjective C
License MIT
ReleasedLast Release Dec 2014

Maintained by Oliver Letterer.

swift-async 0.1.0

swift-async provides a common interface for asynchronous control flow. It allows You to group async tasks, like loading data from the network or performing long running computations, together with a unified completion handler.

Usage

For the sake of simplicity, consider the following model:

class Room {
    let number: Int
}

class Floor {
    let name: String
}

class Building {
    func performAsyncWork1(completionHandler: (NSError?) -> ()) {
        // perform async work and invoke completionHandler when done
    }

    func fetchRoomsOnFloor(floor: Floor, completionHandler: ([Room]?, NSError?) -> ()) {
        // fetch some data here and invoke completionHandler when done
    }

    func fetchFloors(completionHandler: ([Floor]?, NSError?) -> ()) {
        // fetch some data here and invoke completionHandler when done
    }
}

Executing tasks in parallel

let building1 = Building()
let building2 = Building()

let tasks = [
    Async.bind { building1.fetchFloors($0) },
    Async.bind { building1.fetchRoomsOnFloor(Floor(name: "First floor"), $0) },

    Async.bind { building2.fetchFloors($0) },
    Async.bind { building2.fetchRoomsOnFloor(Floor(name: "First floor"), $0) },
]

Async.parallel(tasks) { (results, error) in
    if let error = error {
        println("Error: \(error)")
    } else if let results = results {
        let floors = results[0] as [Floor]
        let rooms = results[1] as [Room]

        println("Got floors: \(floors)")
        println("And rooms: \(rooms)")
    }
}

Executing tasks one after another

let building1 = Building()
let building2 = Building()

let tasks = [
    building1.performAsyncWork1,
    building2.performAsyncWork2,
    Async.bind { building1.performAsyncWorkWithObject(nil, completionHandler: $0) },
]

Async.series(tasks) { (error) in
    if let error = error {
        return println("Error: \(error)")
    } else {
        println("all tasks succeeded")
    }
}

Asumptions

All functions must take a unified completion handler that either takes

  • a single NSError? argument
  • or a generic type T? and a NSError? argument

swift-async is not thread safe, so You need to make sure that all completion handlers are executed on the same thread.

Contact

License

swift-async is released under an MIT license. See LICENSE for more information.