Grand Swift Dispatch

Provides simple way to create and use NSOperationQueues in Swift.

Types

• NSOperationQueue is simply typealiased to Queue to save keystrokes.

Accessing Queues

• Main Queue is accessible via Queue.Main
• Current queue is accessible via Queue.Current
• There is shared queue for each Quality of Service:
  • User Interactive operations via Queue.Interactive
  • User Initiated operations via Queue.User
  • Utility operations via Queue.Utility
  • Background operations via Queue.Background

Simple Perform

• There is a single method name perform:

  Queue.Utility.perform {
      // Work
      Queue.Main.perform {
          // Callback
      }
  }

• Optional argument for waiting:

  Queue.Utility.perform(wait: Yes) {
      // Synchronous
  }

• Optional delay argument:

  Queue.Utility.perform(delay: 1.5) {
      // Delayed
  }

No Direct Deadlock

Waiting for operation on current queue doesn't create deadlock. The operation is invoked directly and is not even scheduled:

Queue.Current.perform(wait: Yes) {
    // Directly invoked
}

• Will not prevent all deadlocks, only direct ones.

Smart Waiting

When no wait: argument is given and you are targetting current queue, the operation is also invoked directly:

// On Main Queue

Queue.Main.perform {
    // Directly invoked
}

• The operation is invoked by the desired queue.
• Doesn't break your call stack.
• Provide explicit wait: No to opt-out.

Initializer

Convenience initializer that specifies Quality of Service and concurrency:

let queue = Queue(quality: .Utility, concurrent: No, adjective: "Processing")

Description

Generated description for each Queue instance:

println(Queue.Main) // Main Interactive Serial Queue (Current)
println(Queue.Background) // Global Background Concurrent Queue
println(queue) // Processing Utility Serial Queue

• Argument adjective: from the initializer is used in the description.
• Name of Quality of Service is included.
• Concurrency is also included.
• Current queues are marked.