Create and use PostponingBlock.

Core/Sources/Core/DataFile.swift

@@ -21,20 +21,24 @@ public protocol DataFileDelegate: AnyObject {
 	private var isDirty = false {
 		didSet {
 			if isDirty {
-				restartTimer()
+				postponingBlock.runInFuture()
 			}
 			else {
-				invalidateTimer()
+				postponingBlock.cancelRun()
 			}
 		}
 	}
 
 	private let fileURL: URL
-	private let saveInterval: TimeInterval = 1.0
-	private var timer: Timer?
+
+	private lazy var postponingBlock: PostponingBlock = {
+		PostponingBlock(delayInterval: 1.0) { [weak self] in
+			self?.saveToDiskIfNeeded()
+		}
+	}()
 
 	public init(fileURL: URL) {
-		
+
 		self.fileURL = fileURL
 	}
 
@@ -64,33 +68,8 @@ private extension DataFile {
 
 	func saveToDiskIfNeeded() {
 
-		assert(Thread.isMainThread)
-
 		if isDirty {
 			save()
 		}
 	}
-
-	func restartTimer() {
-
-		assert(Thread.isMainThread)
-
-		invalidateTimer()
-
-		timer = Timer.scheduledTimer(withTimeInterval: saveInterval, repeats: false) { timer in
-			MainActor.assumeIsolated {
-				self.saveToDiskIfNeeded()
-			}
-		}
-	}
-
-	func invalidateTimer() {
-
-		assert(Thread.isMainThread)
-
-		if let timer, timer.isValid {
-			timer.invalidate()
-		}
-		timer = nil
-	}
 }

Core/Sources/Core/PostponingBlock.swift

@@ -0,0 +1,51 @@
+//
+//  PostponingBlock.swift
+//
+//
+//  Created by Brent Simmons on 6/9/24.
+//
+
+import Foundation
+
+/// Runs a block of code in the future. Each time `runInFuture` is called, the block is postponed again until the future by `delayInterval`.
+@MainActor public final class PostponingBlock {
+
+	private let block: () -> Void
+	private let delayInterval: TimeInterval
+	private var timer: Timer?
+
+	public init(delayInterval: TimeInterval, block: @escaping () -> Void) {
+
+		self.block = block
+		self.delayInterval = delayInterval
+	}
+
+	/// Run the block in `delayInterval` seconds, canceling any run about to happen before then.
+	public func runInFuture() {
+
+		invalidateTimer()
+
+		timer = Timer.scheduledTimer(withTimeInterval: delayInterval, repeats: false) { timer in
+			MainActor.assumeIsolated {
+				self.block()
+			}
+		}
+	}
+
+	/// Cancel any upcoming run.
+	public func cancelRun() {
+
+		invalidateTimer()
+	}
+}
+
+private extension PostponingBlock {
+
+	func invalidateTimer() {
+
+		if let timer, timer.isValid {
+			timer.invalidate()
+		}
+		timer = nil
+	}
+}

Shared/SmartFeeds/SmartFeed.swift

@@ -48,6 +48,15 @@ final class SmartFeed: PseudoFeed {
 	}
 	#endif
 
+	private lazy var postponingBlock: PostponingBlock = {
+		PostponingBlock(delayInterval: 1.0) {
+			Task {
+				try? await self.fetchUnreadCounts()
+			}
+		}
+	}()
+	
+	private var fetchUnreadCountsTask: Task<Void, Never>?
 	private let delegate: SmartFeedDelegate
 	private var unreadCounts = [String: Int]()
 
@@ -63,7 +72,7 @@ final class SmartFeed: PseudoFeed {
 		}
 	}
 
-	@MainActor @objc func fetchUnreadCounts() {
+	@MainActor func fetchUnreadCounts() async throws {
 
 		let activeAccounts = AccountManager.shared.activeAccounts
 
@@ -79,11 +88,9 @@ final class SmartFeed: PseudoFeed {
 			updateUnreadCount()
 			return
 		}
-		
-		Task { @MainActor in
-			for account in activeAccounts {
-				await fetchUnreadCount(for: account)
-			}
+
+		for account in activeAccounts {
+			await fetchUnreadCount(for: account)
 		}
 	}
 }
@@ -104,7 +111,8 @@ extension SmartFeed: ArticleFetcher {
 private extension SmartFeed {
 
 	@MainActor func queueFetchUnreadCounts() {
-		CoalescingQueue.standard.add(self, #selector(fetchUnreadCounts))
+
+		postponingBlock.runInFuture()
 	}
 
 	@MainActor func fetchUnreadCount(for account: Account) async {
@@ -125,3 +133,4 @@ private extension SmartFeed {
 		unreadCount = unread
 	}
 }
+