iOS: fix memory leak issues (#486)

fix memory leak issues

Author: nancywu1

ios/core/Sources/Player/HeadlessPlayer.swift

@@ -164,10 +164,7 @@ public protocol HeadlessPlayer {
 public extension HeadlessPlayer {
     /// The current state of Player
     var state: BaseFlowState? {
-        guard
-            let jsState = jsPlayerReference?.invokeMethod("getState", withArguments: [])
-        else { return nil }
-        return BaseFlowState.createInstance(value: jsState)
+        return jsPlayerReference?.getState()
     }
 
     /**
@@ -221,6 +218,10 @@ public extension HeadlessPlayer {
         - completion: A completion handler for when the flow has completed
      */
     func start(flow: String, completion: @escaping (Result<CompletedState, PlayerError>) -> Void) {
+        // declare these variables outside and reference them inside the errorHandler to prevent retain cycle
+        let playerRef = jsPlayerReference
+        let loggerRef = logger
+
         let promiseHandler: @convention(block) (JSValue?) -> Void = { completedState in
             guard
                 let result = CompletedState.createInstance(from: completedState)
@@ -231,17 +232,17 @@ public extension HeadlessPlayer {
         }
         let errorHandler: @convention(block) (JSValue?) -> Void = { _ in
             guard
-                let result = self.state as? ErrorState
-            else {
+                let result = playerRef?.getState() as? ErrorState else {
                 return completion(.failure(PlayerError.jsConversionFailure))
             }
-            logger.e(result.error)
+
+            loggerRef.e(result.error)
             completion(.failure(PlayerError.promiseRejected(error: result)))
         }
 
         // Ensure these get created because otherwise we will never know when the flow ends/errors
         guard
-            let context = jsPlayerReference?.context,
+            let context = playerRef?.context,
             let flowObject = context.evaluateScript("(\(flow))"),
             !flowObject.isUndefined,
             let callback = JSValue(object: promiseHandler, in: context),
@@ -251,7 +252,7 @@ public extension HeadlessPlayer {
         }
 
         // Should not be possible due to fatalError in constructor, but just for handling optionals safely
-        guard let player = jsPlayerReference else { return completion(.failure(PlayerError.playerNotInstantiated)) }
+        guard let player = playerRef else { return completion(.failure(PlayerError.playerNotInstantiated)) }
         player
             .invokeMethod("start", withArguments: [flowObject])
             .invokeMethod("then", withArguments: [callback])
@@ -347,3 +348,12 @@ internal extension JSContext {
         return value
     }
 }
+
+private extension JSValue {
+    // put getState in extension so it can be accessed by the computed property in HeadlessPlayer.state and also inside the ErrorHandler by the playerReference
+    func getState() -> BaseFlowState? {
+        guard let jsState = self.invokeMethod("getState", withArguments: [])
+        else { return nil }
+        return BaseFlowState.createInstance(value: jsState)
+    }
+}

ios/swiftui/Sources/ManagedPlayer/ManagedPlayer.swift

@@ -147,6 +147,9 @@ internal struct ManagedPlayer14<Loading: View, Fallback: View>: View {
 
     public var body: some View {
         bodyContent(viewModel.stateTransition.call() ?? .identity)
+            .onDisappear {
+                context.clearExceptionHandler()
+            }
     }
 
     private func bodyContent(_ transitionInfo: PlayerViewTransition) -> some View {

ios/swiftui/Sources/ManagedPlayer/ManagedPlayerViewModel.swift

@@ -114,12 +114,12 @@ public class ManagedPlayerViewModel: ObservableObject, NativePlugin {
     }
 
     public func apply<P>(player: P) where P: HeadlessPlayer {
-        player.hooks?.state.tap({ (state) in
+        player.hooks?.state.tap({ [weak self] (state) in
             guard let inProgress = state as? InProgressState else {
-                self.currentState = nil
+                self?.currentState = nil
                 return
             }
-            self.currentState = inProgress
+            self?.currentState = inProgress
         })
     }
 

ios/swiftui/Sources/SwiftUIPlayer.swift

@@ -84,8 +84,8 @@ public struct SwiftUIPlayer: View, HeadlessPlayer {
                 self.onViewController(controller)
             }
 
-            hooks.state.tap { newState in
-                self.state = newState
+            hooks.state.tap { [weak self] newState in
+                self?.state = newState
             }
 
             guard !flow.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty else {
@@ -109,6 +109,12 @@ public struct SwiftUIPlayer: View, HeadlessPlayer {
             registry.resetView()
         }
 
+        /// Clear the exceptionHandler of the context to remove reference to the logger
+        /// should be called when ManagedPlayer gets tore down
+        public func clearExceptionHandler() {
+            player?.context.exceptionHandler = nil
+        }
+
         /// Returns `player` but asserts that it is not nil. Used from methods that should not be called
         /// when we are unloaded.
         private var expectedPlayer: JSValue? {