kshivang · April 11, 2025 15:13 · Mar 11, 2020 · Mar 11, 2020 · Mar 11, 2020 · Mar 11, 2020
diff --git a/AVPlayer+Combine.swift b/AVPlayer+Combine.swift
@@ -4,7 +4,7 @@ import Combine
 // simply use 
 // player.periodicTimePublisher()
 //   .receive(on: RunLoop.main)
-//   .assign(to: elapsedSec)
+//   .assign(to: \SomeClass.elapsedTime, on: someInstance)
 //   .store(in: &cancelBag)
 
 

diff --git a/AVPlayer+Combine.swift b/AVPlayer+Combine.swift
@@ -0,0 +1,65 @@
+import AVFoundation
+import Combine
+
+// simply use 
+// player.periodicTimePublisher()
+//   .receive(on: RunLoop.main)
+//   .assign(to: elapsedSec)
+//   .store(in: &cancelBag)
+
+
+extension AVPlayer {
+    func periodicTimePublisher(forInterval interval: CMTime = CMTime(seconds: 0.5, preferredTimescale: CMTimeScale(NSEC_PER_SEC))) -> AnyPublisher<CMTime, Never> {
+        Publisher(self, forInterval: interval)
+            .eraseToAnyPublisher()
+    }
+}
+
+fileprivate extension AVPlayer {
+    private struct Publisher: Combine.Publisher {
+
+        typealias Output = CMTime
+        typealias Failure = Never
+
+        var player: AVPlayer
+        var interval: CMTime
+
+        init(_ player: AVPlayer, forInterval interval: CMTime) {
+            self.player = player
+            self.interval = interval
+        }
+
+        func receive<S>(subscriber: S) where S : Subscriber, Publisher.Failure == S.Failure, Publisher.Output == S.Input {
+            let subscription = CMTime.Subscription(subscriber: subscriber, player: player, forInterval: interval)
+            subscriber.receive(subscription: subscription)
+        }
+    }
+}
+
+fileprivate extension CMTime {
+    final class Subscription<SubscriberType: Subscriber>: Combine.Subscription where SubscriberType.Input == CMTime, SubscriberType.Failure == Never {
+
+        var player: AVPlayer? = nil
+        var observer: Any? = nil
+
+        init(subscriber: SubscriberType, player: AVPlayer, forInterval interval: CMTime) {
+            self.player = player
+            observer = player.addPeriodicTimeObserver(forInterval: interval, queue: nil) { time in
+                _ = subscriber.receive(time)
+            }
+        }
+
+        func request(_ demand: Subscribers.Demand) {
+            // We do nothing here as we only want to send events when they occur.
+            // See, for more info: https://developer.apple.com/documentation/combine/subscribers/demand
+        }
+
+        func cancel() {
+            if let observer = observer {
+                player?.removeTimeObserver(observer)
+            }
+            observer = nil
+            player = nil
+        }
+    }
+}