Write widget data when article status changes happen. Fixes #3567

Shared/Widget/WidgetDataEncoder.swift

@@ -20,21 +20,48 @@ public final class WidgetDataEncoder {
 	private let log = OSLog(subsystem: Bundle.main.bundleIdentifier!, category: "Application")
 	private let fetchLimit = 7
 	
-	private var backgroundTaskID: UIBackgroundTaskIdentifier!
 	private lazy var appGroup = Bundle.main.object(forInfoDictionaryKey: "AppGroup") as! String
 	private lazy var containerURL = FileManager.default.containerURL(forSecurityApplicationGroupIdentifier: appGroup)
 	private lazy var imageContainer = containerURL?.appendingPathComponent("widgetImages", isDirectory: true)
 	private lazy var dataURL = containerURL?.appendingPathComponent("widget-data.json")
 	
-	static let shared = WidgetDataEncoder()
+	private let encodeWidgetDataQueue = CoalescingQueue(name: "Encode the Widget Data", interval: 5.0)
-	private init () {
+
+	init () {
 		if imageContainer != nil {
 			try? FileManager.default.createDirectory(at: imageContainer!, withIntermediateDirectories: true, attributes: nil)
 		}
+		if #available(iOS 14, *) {
+			NotificationCenter.default.addObserver(self, selector: #selector(statusesDidChange(_:)), name: .StatusesDidChange, object: nil)
+		}
+	}
+	
+	func encodeIfNecessary() {
+		encodeWidgetDataQueue.performCallsImmediately()
+	}
+
+	@available(iOS 14, *)
+	@objc func statusesDidChange(_ note: Notification) {
+		encodeWidgetDataQueue.add(self, #selector(performEncodeWidgetData))
+	}
+
+	@available(iOS 14, *)
+	@objc private func performEncodeWidgetData() {
+		// We will be on the Main Thread when the encodeIfNecessary function is called. We want
+		// block the main thread in that case so that the widget data is encoded. If it is on
+		// a background Thread, it was called by the CoalescingQueue. In that case we need to
+		// move it to the Main Thread and want to execute it async.
+		if Thread.isMainThread {
+			encodeWidgetData()
+		} else {
+			DispatchQueue.main.async {
+				self.encodeWidgetData()
+			}
+		}
 	}
 	
 	@available(iOS 14, *)
-	func encodeWidgetData() throws {
+	private func encodeWidgetData() {
 		flushSharedContainer()
 		os_log(.debug, log: log, "Starting encoding widget data.")
 		
@@ -89,10 +116,6 @@ public final class WidgetDataEncoder {
 			DispatchQueue.global().async { [weak self] in
 				guard let self = self else { return }
 				
-				self.backgroundTaskID = UIApplication.shared.beginBackgroundTask (withName: "com.ranchero.NetNewsWire.Encode") {
-					 UIApplication.shared.endBackgroundTask(self.backgroundTaskID!)
-					self.backgroundTaskID = .invalid
-				}
 				let encodedData = try? JSONEncoder().encode(latestData)
 				
 				os_log(.debug, log: self.log, "Finished encoding widget data.")
@@ -104,14 +127,11 @@ public final class WidgetDataEncoder {
 				if FileManager.default.createFile(atPath: self.dataURL!.path, contents: encodedData, attributes: nil) {
 					os_log(.debug, log: self.log, "Wrote widget data to container.")
 					WidgetCenter.shared.reloadAllTimelines()
-					UIApplication.shared.endBackgroundTask(self.backgroundTaskID!)
-					self.backgroundTaskID = .invalid
-				} else {
-					UIApplication.shared.endBackgroundTask(self.backgroundTaskID!)
-					self.backgroundTaskID = .invalid
 				}
 				
 			}
+		} catch {
+			os_log(.error, log: log, "WidgetDataEncoder failed to write the widget data.")
 		}
 	}
 	

iOS/AppDelegate.swift

@@ -45,6 +45,7 @@ class AppDelegate: UIResponder, UIApplicationDelegate, UNUserNotificationCenterD
 	var webFeedIconDownloader: WebFeedIconDownloader!
 	var extensionContainersFile: ExtensionContainersFile!
 	var extensionFeedAddRequestFile: ExtensionFeedAddRequestFile!
+	var widgetDataEncoder: WidgetDataEncoder!
 	
 	var unreadCount = 0 {
 		didSet {
@@ -114,6 +115,8 @@ class AppDelegate: UIResponder, UIApplicationDelegate, UNUserNotificationCenterD
 		extensionContainersFile = ExtensionContainersFile()
 		extensionFeedAddRequestFile = ExtensionFeedAddRequestFile()
 		
+		widgetDataEncoder = WidgetDataEncoder()
+		
 		syncTimer = ArticleStatusSyncTimer()
 		
 		#if DEBUG
@@ -172,6 +175,7 @@ class AppDelegate: UIResponder, UIApplicationDelegate, UNUserNotificationCenterD
 	
 	func prepareAccountsForBackground() {
 		extensionFeedAddRequestFile.suspend()
+		widgetDataEncoder.encodeIfNecessary()
 		syncTimer?.invalidate()
 		scheduleBackgroundFeedRefresh()
 		syncArticleStatus()
@@ -398,9 +402,6 @@ private extension AppDelegate {
 			}
 			AccountManager.shared.refreshAll(errorHandler: ErrorHandler.log) { [unowned self] in
 				if !AccountManager.shared.isSuspended {
-					if #available(iOS 14, *) {
-						try? WidgetDataEncoder.shared.encodeWidgetData()
-					}
 					self.suspendApplication()
 					os_log("Account refresh operation completed.", log: self.log, type: .info)
 					task.setTaskCompleted(success: true)
@@ -445,9 +446,6 @@ private extension AppDelegate {
 		self.prepareAccountsForBackground()
 		account!.syncArticleStatus(completion: { [weak self] _ in
 			if !AccountManager.shared.isSuspended {
-				if #available(iOS 14, *) {
-					try? WidgetDataEncoder.shared.encodeWidgetData()
-				}
 				self?.prepareAccountsForBackground()
 				self?.suspendApplication()
 			}
@@ -474,9 +472,6 @@ private extension AppDelegate {
 		account!.markArticles(article!, statusKey: .starred, flag: true) { _ in }
 		account!.syncArticleStatus(completion: { [weak self] _ in
 			if !AccountManager.shared.isSuspended {
-				if #available(iOS 14, *) {
-					try? WidgetDataEncoder.shared.encodeWidgetData()
-				}
 				self?.prepareAccountsForBackground()
 				self?.suspendApplication()
 			}

iOS/SceneDelegate.swift

@@ -66,9 +66,6 @@ class SceneDelegate: UIResponder, UIWindowSceneDelegate {
 	}
 	
 	func sceneDidEnterBackground(_ scene: UIScene) {
-		if #available(iOS 14, *) {
-			try? WidgetDataEncoder.shared.encodeWidgetData()
-		}
 		ArticleStringFormatter.emptyCaches()
 		appDelegate.prepareAccountsForBackground()
 	}