BackOnlyErrorDelegate.swift

/**
 UIAlertViewDelegate used when the user can only go back, and so the associated handler
 has no parameters.
 */
private class BackOnlyErrorDelegate: NSObject, UIAlertViewDelegate {
	private let handler: () -> Void

	private init(handler: () -> Void) {
		self.handler = handler
	}

	func alertView(alertView: UIAlertView, clickedButtonAtIndex buttonIndex: Int) {
		switch buttonIndex {
		case alertView.cancelButtonIndex:
			handler()
		default:
			logAndAbort("UIAlertView selected an option that was not cancel")
		}
	}
}