Keep track of DB being deleted on BackgroundDatabaseObserver

GetStream · Dec 12, 2023 · baaa31e · baaa31e
1 parent 5ea4f83
commit baaa31e
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Showing 2 changed files with 39 additions and 2 deletions.
diff --git a/Sources/StreamChat/Controllers/DatabaseObserver/BackgroundDatabaseObserver.swift b/Sources/StreamChat/Controllers/DatabaseObserver/BackgroundDatabaseObserver.swift
@@ -49,6 +49,18 @@ class BackgroundDatabaseObserver<Item, DTO: NSManagedObject> {
         }
     }
 
+    private var _deletingDatabase: Bool = false
+    private var deletingDatabase: Bool {
+        get {
+            queue.sync { _deletingDatabase }
+        }
+        set {
+            queue.async(flags: .barrier) {
+                self._deletingDatabase = newValue
+            }
+        }
+    }
+
     deinit {
         releaseNotificationObservers?()
     }
@@ -104,7 +116,7 @@ class BackgroundDatabaseObserver<Item, DTO: NSManagedObject> {
     /// Starts observing the changes in the database.
     /// - Throws: An error if the fetch  fails.
     func startObserving() throws {
-        guard !isInitialized else { return }
+        guard !isInitialized && !deletingDatabase else { return }
         isInitialized = true
 
         do {
@@ -191,7 +203,7 @@ class BackgroundDatabaseObserver<Item, DTO: NSManagedObject> {
 
         var items: [Item?] = []
         items = objects.map { [weak self] in
-            guard $0.isValid else { return nil }
+            guard self?.deletingDatabase == false else { return nil }
             return try? self?.itemCreator($0)
         }
 
@@ -211,6 +223,11 @@ extension BackgroundDatabaseObserver: DatabaseObserverRemovalListener {
     /// are received.
     private func listenForRemoveAllDataNotifications() {
         listenForRemoveAllDataNotifications(
+            updateIsDeleting: { [weak self] isDeleting in
+                self?.queue.async(flags: .barrier) {
+                    self?._deletingDatabase = isDeleting
+                }
+            },
             isBackground: true,
             frc: frc,
             changeAggregator: changeAggregator,

diff --git a/Sources/StreamChat/Controllers/DatabaseObserver/DatabaseObserverRemovalListener.swift b/Sources/StreamChat/Controllers/DatabaseObserver/DatabaseObserverRemovalListener.swift
@@ -11,6 +11,7 @@ protocol DatabaseObserverRemovalListener: AnyObject {
 
 extension DatabaseObserverRemovalListener {
     func listenForRemoveAllDataNotifications<Item, DTO: NSManagedObject>(
+        updateIsDeleting: @escaping (Bool) -> Void,
         isBackground: Bool,
         frc: NSFetchedResultsController<DTO>,
         changeAggregator: ListChangeAggregator<DTO, Item>,
@@ -28,6 +29,7 @@ extension DatabaseObserverRemovalListener {
             object: context,
             queue: .main
         ) { [weak frc, weak context, weak changeAggregator] _ in
+            updateIsDeleting(true)
             guard let frc = frc, let context = context, let changeAggregator = changeAggregator else { return }
             guard let fetchResultsController = frc as? NSFetchedResultsController<NSFetchRequestResult> else { return }
 
@@ -68,6 +70,7 @@ extension DatabaseObserverRemovalListener {
             object: context,
             queue: .main
         ) { _ in
+            updateIsDeleting(false)
             onCompletion()
         }
 
@@ -76,4 +79,21 @@ extension DatabaseObserverRemovalListener {
             notificationCenter?.removeObserver(didRemoveAllDataNotificationObserver)
         }
     }
+
+    func listenForRemoveAllDataNotifications<Item, DTO: NSManagedObject>(
+        isBackground: Bool,
+        frc: NSFetchedResultsController<DTO>,
+        changeAggregator: ListChangeAggregator<DTO, Item>,
+        onItemsRemoval: @escaping (@escaping () -> Void) -> Void,
+        onCompletion: @escaping () -> Void
+    ) {
+        listenForRemoveAllDataNotifications(
+            updateIsDeleting: { _ in },
+            isBackground: isBackground,
+            frc: frc,
+            changeAggregator: changeAggregator,
+            onItemsRemoval: onItemsRemoval,
+            onCompletion: onCompletion
+        )
+    }
 }