View difference between Paste ID: 57Q4BSj8 and ue3emfxu

-import AVFoundation
+import AVFoundation
-
+
-/// The `PlayerLoader` class provides a callback mechanism for consumers of `AVPlayer` when loading a resource.
+/// The `PlayerLoader` class provides a callback mechanism for consumers of `AVPlayer` when loading a resource.
-/// AVFoundation works by an inconvenient series of APIs that rely on KVO for asynchronous operations. This class
+/// AVFoundation works by an inconvenient series of APIs that rely on KVO for asynchronous operations. This class
-/// eliminates the boilerplate that KVO imposes and makes the callsite much more clean.
+/// eliminates the boilerplate that KVO imposes and makes the callsite much more clean.
-public final class PlayerLoader: NSObject {
+public final class PlayerLoader: NSObject {
-    public typealias Callback = (AVPlayer) -> ()
+    public typealias Callback = (AVPlayer) -> ()
-
+
-    /// The callback will initialize to a non-nil value. The callback is set to nil once it's invoked, at which time the
+    /// The callback will initialize to a non-nil value. The callback is set to nil once it's invoked, at which time the
-    /// KVO observation is removed. This is necessary to avoid double-removing the KVO observation.
+    /// KVO observation is removed. This is necessary to avoid double-removing the KVO observation.
-    private var callback: Callback?
+    private var callback: Callback?
-
+
-    private let player: AVPlayer
+    private let player: AVPlayer
-
+
-    // This is declared `var` because we have to take its pointer value
+    // This is declared `var` because we have to take its pointer value
-    private static var observationContext = NSObject()
+    private static var observationContext = NSObject()
-    private let observationKeypath = #keyPath(AVPlayer.currentItem.status)
+    private let observationKeypath = #keyPath(AVPlayer.currentItem.status)
-
+
-    init(player: AVPlayer, callback: @escaping Callback) {
+    init(player: AVPlayer, callback: @escaping Callback) {
-        self.callback = callback
+        self.callback = callback
-        self.player = player
+        self.player = player
-
+
-        super.init()
+        super.init()
-
+
-        if self.player.currentItem?.status == AVPlayerItemStatus.readyToPlay {
+        if self.player.currentItem?.status == AVPlayerItemStatus.readyToPlay {
-            self.callback?(self.player)
+            self.callback?(self.player)
-        } else {
+        } else {
-            self.player.addObserver(
+            self.player.addObserver(
-                self,
+                self,
-                forKeyPath: self.observationKeypath,
+                forKeyPath: self.observationKeypath,
-                options: [NSKeyValueObservingOptions.new],
+                options: [NSKeyValueObservingOptions.new],
-                context: &PlayerLoader.observationContext
+                context: &PlayerLoader.observationContext
-            )
+            )
-        }
+        }
-    }
+    }
-
+
-    public convenience init(url: URL, callback: @escaping Callback) {
+    public convenience init(url: URL, callback: @escaping Callback) {
-        self.init(player: AVPlayer(url: url), callback: callback)
+        self.init(player: AVPlayer(url: url), callback: callback)
-    }
+    }
-
+
-    override public func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) {
+    override public func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) {
-        guard let context = context, context == &PlayerLoader.observationContext else {
+        guard let context = context, context == &PlayerLoader.observationContext else {
-            return
+            return
-        }
+        }
-
+
-        guard let keyPath = keyPath, keyPath == self.observationKeypath else {
+        guard let keyPath = keyPath, keyPath == self.observationKeypath else {
-            return
+            return
-        }
+        }
-
+
-        guard let currentItem = self.player.currentItem else {
+        guard let currentItem = self.player.currentItem else {
-            return
+            return
-        }
+        }
-
+
-        guard !CMTimeGetSeconds(currentItem.duration).isNaN else {
+        guard !CMTimeGetSeconds(currentItem.duration).isNaN else {
-            return
+            return
-        }
+        }
-
+
-        guard currentItem.status == AVPlayerItemStatus.readyToPlay else {
+        guard currentItem.status == AVPlayerItemStatus.readyToPlay else {
-            return
+            return
-        }
+        }
-
+
-        self.player.removeObserver(self, forKeyPath: self.observationKeypath)
+        self.player.removeObserver(self, forKeyPath: self.observationKeypath)
-
+
-        self.player.preroll(atRate: 1.0) { _ in
+        self.player.preroll(atRate: 1.0) { _ in
-            self.callback?(self.player)
+            self.callback?(self.player)
-            self.callback = nil
+            self.callback = nil
-        }
+        }
-    }
+    }
-
+
-    deinit {
+    deinit {
-        // This is really awkward but is one of the reasons why this class exists in the first place.
+        // This is really awkward but is one of the reasons why this class exists in the first place.
-        if self.callback != nil {
+        if self.callback != nil {
-            self.player.removeObserver(self, forKeyPath: self.observationKeypath)
+            self.player.removeObserver(self, forKeyPath: self.observationKeypath)
-        }
+        }
-    }
+    }
 }