GoodProgress

A delightful progress reporting framework for Swift powered by NSProgress.

NSProgress is a relatively new (iOS 7, OS X 10.9), often overlooked but awesome addition to the Cocoa framework. It provides a way to report the progress of long running tasks across threads and to pause or cancel those tasks. GoodProgress is a tiny wrapper around NSProgress that aims to make reporting progress super nice in Swift.

If you're looking for documentation on NSProgress, check out the following sources:

• class reference
• the OS X 10.9 foundation release notes (update: it's gone)
• the excellent blog post by Ole Begemann
• an example project + post by Jaanus Kase
• another good blog post by thoughtbot's Keith Smiley

Current State

GoodProgress is in very early stages of development. It should not be used for purposes other than experimentation, yet.

In the (bright) future, GoodProgress could be integrated with BrightFutures.

Usage

Where NSProgress is just one class, GoodProgress splits its functionality into two classes: Progress and ProgressSource. ProgressSource is used where progress is being made, Progress is used to observe the progress and to pause or cancel the task. The latter is typically used in or near your view code. For example:

let progress = progress(self.loader.loadNextItems(5))
progress.onProgress { fraction in
	self.progressView.progress = fraction
}

Inside the loadNextItems, a ProgressSource can be used to report the progress:

func loadNextItems(numberOfItems: Int) {
	let source = ProgressSource(totalUnitCount: numberOfItems)
	dispatch_aync(queue, {
		for offset in 1...numberOfItems {
			self.loadItem(self.lastLoadedIndex+offset)
			source.completeUnit()
		}
		self.lastLoadedIndex += numberOfItems
	}
}

A ProgressSource can also combine the progress from multiple ProgressSources:

let source = ProgressSource(totalUnitCount: 100)

source.becomeCurrentWithPendingUnitCount(80)
self.loadImages()
source.resignCurrent()

source.becomeCurrentWithPendingUnitCount(20)
self.loadText()
source.resignCurrent()

source.progress.onProgress { fraction in
	println("progress: \(fraction)") // prints a value from 0.0 to 1.0
}

GoodProgress leverages the power of Swift to offer a nicer way to achive the same:

progress(100) { source in
	source.captureProgress(80) {
		self.loadImages()
	}

	source.captureProgress(20) {
		self.loadText()
	}
}.onProgress { fraction in
	println("progress: \(fraction)") // prints a value from 0.0 to 1.0
}

This example is functionally equivalent to the previous example, but much nicer to write and read.

Contact

I am looking forward to your feedback. I am very much still learning Swift. We all are. Let me know how I could improve GoodProgress by creating an issue, a pull request or by reaching out on twitter. I'm @thomvis88.

License

GoodProgress is available under the MIT license. See the LICENSE file for more info.