Merge pull request #20280 from wordpress-mobile/update-perform-save-i…

…n-notification-sync-mediator

Add another `performAndSave` overload

WordPress/Classes/Services/NotificationSyncMediator.swift

@@ -25,7 +25,7 @@ let NotificationSyncMediatorDidUpdateNotifications = "NotificationSyncMediatorDi
 final class NotificationSyncMediator {
     /// Returns the Main Managed Context
     ///
-    fileprivate let contextManager: CoreDataStack
+    private let contextManager: CoreDataStackSwift
 
     /// Sync Service Remote
     ///
@@ -71,7 +71,7 @@ final class NotificationSyncMediator {
     ///     - manager: ContextManager Instance
     ///     - wordPressComRestApi: The WordPressComRestApi that should be used.
     ///
-    init?(manager: CoreDataStack, dotcomAPI: WordPressComRestApi) {
+    init?(manager: CoreDataStackSwift, dotcomAPI: WordPressComRestApi) {
         guard dotcomAPI.hasCredentials() else {
             return nil
         }
@@ -311,7 +311,7 @@ private extension NotificationSyncMediator {
     ///
     func determineUpdatedNotes(with remoteHashes: [RemoteNotification], completion: @escaping (([String]) -> Void)) {
         Self.operationQueue.addOperation(AsyncBlockOperation { [contextManager] done in
-            contextManager.performAndSave { context in
+            contextManager.performAndSave({ context in
                 let remoteIds = remoteHashes.map { $0.notificationId }
                 let predicate = NSPredicate(format: "(notificationId IN %@)", remoteIds)
                 var localHashes = [String: String]()
@@ -320,19 +320,16 @@ private extension NotificationSyncMediator {
                     localHashes[note.notificationId] = note.notificationHash ?? ""
                 }
 
-                let outdatedIds = remoteHashes
+                return remoteHashes
                     .filter { remote in
                         let localHash = localHashes[remote.notificationId]
                         return localHash == nil || localHash != remote.notificationHash
                     }
                     .map { $0.notificationId }
-
-                DispatchQueue.main.async {
-                    completion(outdatedIds)
-                }
-
+            }, completion: { outdatedIds in
+                completion(outdatedIds)
                 done()
-            }
+            }, on: .main)
         })
     }
 

WordPress/Classes/Utility/ContextManager.swift

@@ -8,6 +8,18 @@ let ContextManagerModelNameCurrent = "$CURRENT"
 
 public protocol CoreDataStackSwift: CoreDataStack {
 
+    /// Execute the given block with a background context and save the changes.
+    ///
+    /// This function _does not block_ its running thread. The block is executed in background and its return value
+    /// is passed onto the `completion` block which is executed on the given `queue`.
+    ///
+    /// - Parameters:
+    ///   - block: A closure which uses the given `NSManagedObjectContext` to make Core Data model changes.
+    ///   - completion: A closure which is called with the return value of the `block`, after the changed made
+    ///         by the `block` is saved.
+    ///   - queue: A queue on which to execute the completion block.
+    func performAndSave<T>(_ block: @escaping (NSManagedObjectContext) -> T, completion: ((T) -> Void)?, on queue: DispatchQueue)
+
     /// Execute the given block with a background context and save the changes _if the block does not throw an error_.
     ///
     /// This function _does not block_ its running thread. The block is executed in background and the return value
@@ -128,6 +140,17 @@ public class ContextManager: NSObject, CoreDataStack, CoreDataStackSwift {
         })
     }
 
+    public func performAndSave<T>(_ block: @escaping (NSManagedObjectContext) -> T, completion: ((T) -> Void)?, on queue: DispatchQueue) {
+        performAndSave(
+            block,
+            completion: { (result: Result<T, Error>) in
+                // It's safe to force-unwrap here, since the `block` does not throw an error.
+                completion?(try! result.get())
+            },
+            on: queue
+        )
+    }
+
     public func performAndSave<T>(_ block: @escaping (NSManagedObjectContext) throws -> T) async throws -> T {
         try await withCheckedThrowingContinuation { continuation in
             performAndSave(block, completion: continuation.resume(with:), on: DispatchQueue.global())