[PP-1504] Resolve Audiobook playback lockup

Palace.xcodeproj/project.pbxproj

@@ -5655,7 +5655,7 @@
 				CODE_SIGN_IDENTITY = "Apple Distribution";
 				"CODE_SIGN_IDENTITY[sdk=iphoneos*]" = "iPhone Distribution";
 				CODE_SIGN_STYLE = Manual;
-				CURRENT_PROJECT_VERSION = 278;
+				CURRENT_PROJECT_VERSION = 279;
 				DEVELOPMENT_TEAM = 88CBA74T8K;
 				"DEVELOPMENT_TEAM[sdk=iphoneos*]" = 88CBA74T8K;
 				ENABLE_BITCODE = NO;
@@ -5714,7 +5714,7 @@
 				CLANG_WARN_NON_LITERAL_NULL_CONVERSION = YES_ERROR;
 				CODE_SIGN_ENTITLEMENTS = Palace/SimplyE.entitlements;
 				CODE_SIGN_IDENTITY = "iPhone Distribution";
-				CURRENT_PROJECT_VERSION = 278;
+				CURRENT_PROJECT_VERSION = 279;
 				DEVELOPMENT_TEAM = 88CBA74T8K;
 				"DEVELOPMENT_TEAM[sdk=iphoneos*]" = 88CBA74T8K;
 				ENABLE_BITCODE = NO;
@@ -5899,7 +5899,7 @@
 				CODE_SIGN_IDENTITY = "Apple Development";
 				"CODE_SIGN_IDENTITY[sdk=iphoneos*]" = "iPhone Distribution";
 				CODE_SIGN_STYLE = Manual;
-				CURRENT_PROJECT_VERSION = 278;
+				CURRENT_PROJECT_VERSION = 279;
 				DEVELOPMENT_TEAM = "";
 				"DEVELOPMENT_TEAM[sdk=iphoneos*]" = 88CBA74T8K;
 				ENABLE_BITCODE = NO;
@@ -5960,7 +5960,7 @@
 				CLANG_WARN_NON_LITERAL_NULL_CONVERSION = YES_ERROR;
 				CODE_SIGN_ENTITLEMENTS = Palace/SimplyE.entitlements;
 				CODE_SIGN_IDENTITY = "iPhone Distribution";
-				CURRENT_PROJECT_VERSION = 278;
+				CURRENT_PROJECT_VERSION = 279;
 				DEVELOPMENT_TEAM = 88CBA74T8K;
 				"DEVELOPMENT_TEAM[sdk=iphoneos*]" = 88CBA74T8K;
 				ENABLE_BITCODE = NO;
@@ -6022,7 +6022,7 @@
 				CODE_SIGN_IDENTITY = "Apple Development";
 				"CODE_SIGN_IDENTITY[sdk=iphoneos*]" = "iPhone Distribution";
 				CODE_SIGN_STYLE = Manual;
-				CURRENT_PROJECT_VERSION = 278;
+				CURRENT_PROJECT_VERSION = 279;
 				DEVELOPMENT_TEAM = "";
 				"DEVELOPMENT_TEAM[sdk=iphoneos*]" = 88CBA74T8K;
 				ENABLE_BITCODE = NO;
@@ -6083,7 +6083,7 @@
 				CLANG_WARN_NON_LITERAL_NULL_CONVERSION = YES_ERROR;
 				CODE_SIGN_ENTITLEMENTS = Palace/SimplyE.entitlements;
 				CODE_SIGN_IDENTITY = "iPhone Distribution";
-				CURRENT_PROJECT_VERSION = 278;
+				CURRENT_PROJECT_VERSION = 279;
 				DEVELOPMENT_TEAM = 88CBA74T8K;
 				"DEVELOPMENT_TEAM[sdk=iphoneos*]" = 88CBA74T8K;
 				ENABLE_BITCODE = NO;

Palace/Book/UI/TPPBookCellDelegate+Extensions.swift

@@ -12,13 +12,26 @@ import PalaceAudiobookToolkit
 let kServerUpdateDelay: Double = 30.0
 let kTimerInterval: Double = 1.0
 
-//TODO: This is a temporary solution to enable location saves from AppDelegate. Investigate a global context to manage state and introduce caching.
-var latestAudiobookLocation: (book: String, location: String)?
-
 private struct AssociatedKeys {
   static var audiobookBookmarkBusinessLogic = "audiobookBookmarkBusinessLogic"
 }
 
+private let locationQueue = DispatchQueue(label: "com.palace.latestAudiobookLocation", attributes: .concurrent)
+private var _latestAudiobookLocation: (book: String, location: String)?
+
+var latestAudiobookLocation: (book: String, location: String)? {
+  get {
+    locationQueue.sync {
+      _latestAudiobookLocation
+    }
+  }
+  set {
+    locationQueue.async(flags: .barrier) {
+      _latestAudiobookLocation = newValue
+    }
+  }
+}
+
 extension TPPBookCellDelegate {
   public func postListeningPosition(at location: String, completion: ((_ response: AnnotationResponse?) -> Void)? = nil) {
     TPPAnnotations.postListeningPosition(forBook: self.book.identifier, selectorValue: location, completion: completion)
@@ -31,14 +44,12 @@ extension TPPBookCellDelegate {
       return objc_getAssociatedObject(self, &AssociatedKeys.audiobookBookmarkBusinessLogic) as? AudiobookBookmarkBusinessLogic
     }
     set {
-      if let newValue = newValue {
-        objc_setAssociatedObject(
-          self,
-          &AssociatedKeys.audiobookBookmarkBusinessLogic,
-          newValue as AudiobookBookmarkBusinessLogic?,
-          .OBJC_ASSOCIATION_RETAIN_NONATOMIC
-        )
-      }
+      objc_setAssociatedObject(
+        self,
+        &AssociatedKeys.audiobookBookmarkBusinessLogic,
+        newValue,
+        .OBJC_ASSOCIATION_RETAIN_NONATOMIC
+      )
     }
   }
 
@@ -264,6 +275,7 @@ extension TPPBookCellDelegate {
         let locationString = String(data: locationData ?? Data(), encoding: .utf8) ?? ""
 
         TPPBookRegistry.shared.setLocation(TPPBookLocation(locationString: locationString, renderer: "PalaceAudiobookToolkit"), forIdentifier: self.book.identifier)
+
         latestAudiobookLocation = (book: self.book.identifier, location: locationString)
       }
     }

Palace/Reader2/Bookmarks/AudiobookBookmarkBusinessLogic.swift

@@ -30,8 +30,14 @@ import PalaceAudiobookToolkit
   }
 
   // MARK: - Bookmark Management
-  
+
   public func saveListeningPosition(at position: TrackPosition, completion: ((String?) -> Void)?) {
+    debounce {
+      self.saveListeningPositionImmediate(at: position, completion: completion)
+    }
+  }
+
+  private func saveListeningPositionImmediate(at position: TrackPosition, completion: ((String?) -> Void)?) {
     let audioBookmark = position.toAudioBookmark()
     audioBookmark.lastSavedTimeStamp = Date().iso8601
     guard let tppLocation = audioBookmark.toTPPBookLocation() else {
@@ -50,7 +56,7 @@ import PalaceAudiobookToolkit
       }
     }
   }
-  
+
   public func saveBookmark(at position: TrackPosition, completion: ((_ position: TrackPosition?) -> Void)? = nil) {
     debounce {
       Task {