notifications as Signal.

Author: andersio

Sources/FoundationExtensions.swift

@@ -12,34 +12,23 @@ import enum Result.NoError
 extension NotificationCenter: ReactiveExtensionsProvider {}
 
 extension Reactive where Base: NotificationCenter {
-	/// Returns a SignalProducer to observe posting of the specified
-	/// notification.
+	/// Returns a Signal to observe posting of the specified notification.
 	///
 	/// - parameters:
 	///   - name: name of the notification to observe
 	///   - object: an instance which sends the notifications
 	///
-	/// - returns: A SignalProducer of notifications posted that match the given
-	///            criteria.
+	/// - returns: A Signal of notifications posted that match the given criteria.
 	///
-	/// - note: If the `object` is deallocated before starting the producer, it
-	///         will terminate immediately with an `interrupted` event.
-	///         Otherwise, the producer will not terminate naturally, so it must
-	///         be explicitly disposed to avoid leaks.
-	public func notifications(forName name: Notification.Name?, object: AnyObject? = nil) -> SignalProducer<Notification, NoError> {
-		// We're weakly capturing an optional reference here, which makes destructuring awkward.
-		let objectWasNil = (object == nil)
-		return SignalProducer { [base = self.base, weak object] observer, disposable in
-			guard object != nil || objectWasNil else {
-				observer.sendInterrupted()
-				return
-			}
-
+	/// - note: The signal does not terminate naturally. Observers must be
+	///         explicitly disposed to avoid leaks.
+	public func notifications(forName name: Notification.Name?, object: AnyObject? = nil) -> Signal<Notification, NoError> {
+		return Signal { [base = self.base] observer in
 			let notificationObserver = base.addObserver(forName: name, object: object, queue: nil) { notification in
 				observer.send(value: notification)
 			}
 
-			disposable += {
+			return ActionDisposable {
 				base.removeObserver(notificationObserver)
 			}
 		}

Tests/ReactiveSwiftTests/FoundationExtensionsSpec.swift

@@ -23,11 +23,11 @@ class FoundationExtensionsSpec: QuickSpec {
 		describe("NotificationCenter.reactive.notifications") {
 			let center = NotificationCenter.default
 
-			it("should send notifications on the producer") {
-				let producer = center.reactive.notifications(forName: .racFirst)
+			it("should send notifications on the signal") {
+				let signal = center.reactive.notifications(forName: .racFirst)
 
 				var notif: Notification? = nil
-				let disposable = producer.startWithValues { notif = $0 }
+				let disposable = signal.observeValues { notif = $0 }
 
 				center.post(name: .racAnother, object: nil)
 				expect(notif).to(beNil())
@@ -36,26 +36,54 @@ class FoundationExtensionsSpec: QuickSpec {
 				expect(notif?.name) == .racFirst
 
 				notif = nil
-				disposable.dispose()
+				disposable?.dispose()
 
 				center.post(name: .racFirst, object: nil)
 				expect(notif).to(beNil())
 			}
 
-			it("should send Interrupted when the observed object is freed") {
-				var observedObject: AnyObject? = NSObject()
-				let producer = center.reactive.notifications(forName: nil, object: observedObject)
-				observedObject = nil
+			it("should be freed if it is not reachable and no observer is attached") {
+				weak var signal: Signal<Notification, NoError>?
+				var isDisposed = false
 
-				var interrupted = false
-				let disposable = producer.startWithInterrupted {
-					interrupted = true
-				}
-				expect(interrupted) == true
+				let disposable: Disposable? = {
+					let innerSignal = center.reactive.notifications(forName: nil)
+						.on(disposed: { isDisposed = true })
 
-				disposable.dispose()
+					signal = innerSignal
+					return innerSignal.observe { _ in }
+				}()
+
+				expect(isDisposed) == false
+				expect(signal).toNot(beNil())
+
+				disposable?.dispose()
+
+				expect(isDisposed) == true
+				expect(signal).to(beNil())
 			}
 
+			it("should be not freed if it still has one or more active observers") {
+				weak var signal: Signal<Notification, NoError>?
+				var isDisposed = false
+
+				let disposable: Disposable? = {
+					let innerSignal = center.reactive.notifications(forName: nil)
+						.on(disposed: { isDisposed = true })
+
+					signal = innerSignal
+					innerSignal.observe { _ in }
+					return innerSignal.observe { _ in }
+				}()
+
+				expect(isDisposed) == false
+				expect(signal).toNot(beNil())
+
+				disposable?.dispose()
+
+				expect(isDisposed) == false
+				expect(signal).toNot(beNil())
+			}
 		}
 	}
 }