Update iOS with latest TimelineModel refactoring

Multiplatform/Shared/CombineExt/ReplaySubject.swift

@@ -0,0 +1,121 @@
+//
+//  ReplaySubject.swift
+//  CombineExt
+//
+//  Created by Jasdev Singh on 13/04/2020.
+//  Copyright © 2020 Combine Community. All rights reserved.
+//
+
+#if canImport(Combine)
+import Combine
+
+/// A `ReplaySubject` is a subject that can buffer one or more values. It stores value events, up to its `bufferSize` in a
+/// first-in-first-out manner and then replays it to
+/// future subscribers and also forwards completion events.
+///
+/// The implementation borrows heavily from [Entwine’s](https://github.com/tcldr/Entwine/blob/b839c9fcc7466878d6a823677ce608da998b95b9/Sources/Entwine/Operators/ReplaySubject.swift).
+@available(OSX 10.15, iOS 13.0, tvOS 13.0, watchOS 6.0, *)
+public final class ReplaySubject<Output, Failure: Error>: Subject {
+	public typealias Output = Output
+	public typealias Failure = Failure
+
+	private let bufferSize: Int
+	private var buffer = [Output]()
+
+	// Keeping track of all live subscriptions, so `send` events can be forwarded to them.
+	private var subscriptions = [Subscription<AnySubscriber<Output, Failure>>]()
+
+	private var completion: Subscribers.Completion<Failure>?
+	private var isActive: Bool { completion == nil }
+
+	/// Create a `ReplaySubject`, buffering up to `bufferSize` values and replaying them to new subscribers
+	/// - Parameter bufferSize: The maximum number of value events to buffer and replay to all future subscribers.
+	public init(bufferSize: Int) {
+		self.bufferSize = bufferSize
+	}
+
+	public func send(_ value: Output) {
+		guard isActive else { return }
+
+		buffer.append(value)
+
+		if buffer.count > bufferSize {
+			buffer.removeFirst()
+		}
+
+		subscriptions.forEach { $0.forwardValueToBuffer(value) }
+	}
+
+	public func send(completion: Subscribers.Completion<Failure>) {
+		guard isActive else { return }
+
+		self.completion = completion
+
+		subscriptions.forEach { $0.forwardCompletionToBuffer(completion) }
+	}
+
+	public func send(subscription: Combine.Subscription) {
+		subscription.request(.unlimited)
+	}
+
+	public func receive<Subscriber: Combine.Subscriber>(subscriber: Subscriber) where Failure == Subscriber.Failure, Output == Subscriber.Input {
+		let subscriberIdentifier = subscriber.combineIdentifier
+
+		let subscription = Subscription(downstream: AnySubscriber(subscriber)) { [weak self] in
+			guard let self = self,
+				  let subscriptionIndex = self.subscriptions
+											  .firstIndex(where: { $0.innerSubscriberIdentifier == subscriberIdentifier }) else { return }
+
+			self.subscriptions.remove(at: subscriptionIndex)
+		}
+
+		subscriptions.append(subscription)
+
+		subscriber.receive(subscription: subscription)
+		subscription.replay(buffer, completion: completion)
+	}
+}
+
+@available(OSX 10.15, iOS 13.0, tvOS 13.0, watchOS 6.0, *)
+extension ReplaySubject {
+	final class Subscription<Downstream: Subscriber>: Combine.Subscription where Output == Downstream.Input, Failure == Downstream.Failure {
+		private var demandBuffer: DemandBuffer<Downstream>?
+		private var cancellationHandler: (() -> Void)?
+
+		fileprivate let innerSubscriberIdentifier: CombineIdentifier
+
+		init(downstream: Downstream, cancellationHandler: (() -> Void)?) {
+			self.demandBuffer = DemandBuffer(subscriber: downstream)
+			self.innerSubscriberIdentifier = downstream.combineIdentifier
+			self.cancellationHandler = cancellationHandler
+		}
+
+		func replay(_ buffer: [Output], completion: Subscribers.Completion<Failure>?) {
+			buffer.forEach(forwardValueToBuffer)
+
+			if let completion = completion {
+				forwardCompletionToBuffer(completion)
+			}
+		}
+
+		func forwardValueToBuffer(_ value: Output) {
+			_ = demandBuffer?.buffer(value: value)
+		}
+
+		func forwardCompletionToBuffer(_ completion: Subscribers.Completion<Failure>) {
+			demandBuffer?.complete(completion: completion)
+		}
+
+		func request(_ demand: Subscribers.Demand) {
+			_ = demandBuffer?.demand(demand)
+		}
+
+		func cancel() {
+			cancellationHandler?()
+			cancellationHandler = nil
+
+			demandBuffer = nil
+		}
+	}
+}
+#endif

Multiplatform/Shared/CombineExt/ShareReplay.swift

@@ -0,0 +1,24 @@
+//
+//  ShareReplay.swift
+//  CombineExt
+//
+//  Created by Jasdev Singh on 13/04/2020.
+//  Copyright © 2020 Combine Community. All rights reserved.
+//
+
+#if canImport(Combine)
+import Combine
+
+@available(OSX 10.15, iOS 13.0, tvOS 13.0, watchOS 6.0, *)
+public extension Publisher {
+	/// A variation on [share()](https://developer.apple.com/documentation/combine/publisher/3204754-share)
+	/// that allows for buffering and replaying a `replay` amount of value events to future subscribers.
+	///
+	/// - Parameter count: The number of value events to buffer in a first-in-first-out manner.
+	/// - Returns: A publisher that replays the specified number of value events to future subscribers.
+	func share(replay count: Int) -> Publishers.Autoconnect<Publishers.Multicast<Self, ReplaySubject<Output, Failure>>> {
+		multicast { ReplaySubject(bufferSize: count) }
+			.autoconnect()
+	}
+}
+#endif

Multiplatform/Shared/Sidebar/SidebarModel.swift

@@ -75,6 +75,7 @@ private extension SidebarModel {
 			.removeDuplicates(by: { previousFeeds, currentFeeds in
 				return previousFeeds.elementsEqual(currentFeeds, by: { $0.feedID == $1.feedID })
 			})
+			.share(replay: 1)
 			.eraseToAnyPublisher()
 	}
 	
@@ -107,7 +108,7 @@ private extension SidebarModel {
 			.compactMap {  [weak self] _, readFilter, selectedFeeds in
 				self?.rebuildSidebarItems(isReadFiltered: readFilter, selectedFeeds: selectedFeeds)
 			}
-			.share()
+			.share(replay: 1)
 			.eraseToAnyPublisher()
 	}
 	

Multiplatform/Shared/Timeline/TimelineModel.swift

@@ -26,8 +26,8 @@ class TimelineModel: ObservableObject, UndoableCommandRunner {
 	weak var delegate: TimelineModelDelegate?
 	
 	@Published var nameForDisplay = ""
-	@Published var selectedArticleIDs = Set<String>()  // Don't use directly.  Use selectedArticles
-	@Published var selectedArticleID: String? = nil    // Don't use directly.  Use selectedArticles
+	@Published var selectedTimelineItemIDs = Set<String>()  // Don't use directly.  Use selectedTimelineItemsPublisher
+	@Published var selectedTimelineItemID: String? = nil    // Don't use directly.  Use selectedTimelineItemsPublisher
 	@Published var isReadFiltered: Bool? = nil
 
 	var timelineItemsPublisher: AnyPublisher<[TimelineItem], Never>?
@@ -40,15 +40,16 @@ class TimelineModel: ObservableObject, UndoableCommandRunner {
 
 	private var cancellables = Set<AnyCancellable>()
 
-	private var sortDirectionSubject = PassthroughSubject<Bool, Never>()
-	private var groupByFeedSubject = PassthroughSubject<Bool, Never>()
+	private var sortDirectionSubject = ReplaySubject<Bool, Never>(bufferSize: 1)
+	private var groupByFeedSubject = ReplaySubject<Bool, Never>(bufferSize: 1)
 	
 	init(delegate: TimelineModelDelegate) {
 		self.delegate = delegate
-//		subscribeToArticleStatusChanges()
 		subscribeToUserDefaultsChanges()
+		subscribeToReadFilterChanges()
 		subscribeToArticleFetchChanges()
 		subscribeToSelectedArticleSelectionChanges()
+//		subscribeToArticleStatusChanges()
 //		subscribeToAccountDidDownloadArticles()
 	}
 	
@@ -78,6 +79,31 @@ class TimelineModel: ObservableObject, UndoableCommandRunner {
 //		}.store(in: &cancellables)
 //	}
 	
+	func subscribeToReadFilterChanges() {
+		guard let selectedFeedsPublisher = delegate?.selectedFeedsPublisher else { return }
+
+		selectedFeedsPublisher.sink { [weak self] feeds in
+			guard let self = self else { return }
+			
+			guard feeds.count == 1, let timelineFeed = feeds.first else {
+				self.isReadFiltered = nil
+				return
+			}
+	
+			guard timelineFeed.defaultReadFilterType != .alwaysRead else {
+				self.isReadFiltered = nil
+				return
+			}
+	
+			if let feedID = timelineFeed.feedID, let readFilterEnabled = self.readFilterEnabledTable[feedID] {
+				self.isReadFiltered =  readFilterEnabled
+			} else {
+				self.isReadFiltered = timelineFeed.defaultReadFilterType == .read
+			}
+		}
+		.store(in: &cancellables)
+	}
+	
 	func subscribeToUserDefaultsChanges() {
 		let kickStartNote = Notification(name: Notification.Name("Kick Start"))
 		NotificationCenter.default.publisher(for: UserDefaults.didChangeNotification)
@@ -97,11 +123,12 @@ class TimelineModel: ObservableObject, UndoableCommandRunner {
 			.map { [weak self] feeds -> Set<Article> in
 				return self?.fetchArticles(feeds: feeds) ?? Set<Article>()
 			}
-			.combineLatest($isReadFiltered, sortDirectionPublisher, groupByPublisher)
-			.compactMap { [weak self] articles, filtered, sortDirection, groupBy -> [TimelineItem] in
+			.combineLatest(sortDirectionPublisher, groupByPublisher)
+			.compactMap { [weak self] articles, sortDirection, groupBy -> [TimelineItem] in
 				let sortedArticles = Array(articles).sortedByDate(sortDirection ? .orderedDescending : .orderedAscending, groupByFeed: groupBy)
 				return self?.buildTimelineItems(articles: sortedArticles) ?? [TimelineItem]()
 			}
+			.share(replay: 1)
 			.eraseToAnyPublisher()
 	}
 	
@@ -218,24 +245,6 @@ private extension TimelineModel {
 	}
 	
 	// MARK: Timeline Management
-	
-//	func resetReadFilter() {
-//		guard feeds.count == 1, let timelineFeed = feeds.first else {
-//			isReadFiltered = nil
-//			return
-//		}
-//
-//		guard timelineFeed.defaultReadFilterType != .alwaysRead else {
-//			isReadFiltered = nil
-//			return
-//		}
-//
-//		if let feedID = timelineFeed.feedID, let readFilterEnabled = readFilterEnabledTable[feedID] {
-//			isReadFiltered =  readFilterEnabled
-//		} else {
-//			isReadFiltered = timelineFeed.defaultReadFilterType == .read
-//		}
-//	}
 
 	func sortParametersDidChange() {
 //		performBlockAndRestoreSelection {

Multiplatform/Shared/Timeline/TimelineView.swift

@@ -38,8 +38,8 @@ struct TimelineView: View {
 					.help(timelineModel.isReadFiltered ?? false ? "Show Read Articles" : "Filter Read Articles")
 				}
 				ScrollViewReader { scrollViewProxy in
-					List(timelineItems, selection: $timelineModel.selectedArticleIDs) { timelineItem in
-						let selected = timelineModel.selectedArticleIDs.contains(timelineItem.article.articleID)
+					List(timelineItems, selection: $timelineModel.selectedTimelineItemIDs) { timelineItem in
+						let selected = timelineModel.selectedTimelineItemIDs.contains(timelineItem.article.articleID)
 						TimelineItemView(selected: selected, width: geometryReaderProxy.size.width, timelineItem: timelineItem)
 							.background(TimelineItemFramePreferenceView(timelineItem: timelineItem))
 					}
@@ -48,7 +48,7 @@ struct TimelineView: View {
 							timelineItemFrames[pref.articleID] = pref.frame
 						}
 					}
-					.onChange(of: timelineModel.selectedArticleIDs) { selectedArticleIDs in
+					.onChange(of: timelineModel.selectedTimelineItemIDs) { selectedArticleIDs in
 						let proxyFrame = geometryReaderProxy.frame(in: .global)
 						for articleID in selectedArticleIDs {
 							if let itemFrame = timelineItemFrames[articleID] {
@@ -70,14 +70,14 @@ struct TimelineView: View {
 			.navigationTitle(Text(verbatim: timelineModel.nameForDisplay))
 			#else
 			ScrollViewReader { scrollViewProxy in
-				List(timelineModel.timelineItems) { timelineItem in
+				List(timelineItems) { timelineItem in
 					ZStack {
-						let selected = timelineModel.selectedArticleID == timelineItem.article.articleID
+						let selected = timelineModel.selectedTimelineItemID == timelineItem.article.articleID
 						TimelineItemView(selected: selected, width: geometryReaderProxy.size.width, timelineItem: timelineItem)
 							.background(TimelineItemFramePreferenceView(timelineItem: timelineItem))
 						NavigationLink(destination: ArticleContainerView(),
 									   tag: timelineItem.article.articleID,
-									   selection: $timelineModel.selectedArticleID) {
+									   selection: $timelineModel.selectedTimelineItemID) {
 							EmptyView()
 						}.buttonStyle(PlainButtonStyle())
 					}
@@ -87,7 +87,7 @@ struct TimelineView: View {
 						timelineItemFrames[pref.articleID] = pref.frame
 					}
 				}
-				.onChange(of: timelineModel.selectedArticleID) { selectedArticleID in
+				.onChange(of: timelineModel.selectedTimelineItemID) { selectedArticleID in
 					let proxyFrame = geometryReaderProxy.frame(in: .global)
 					if let articleID = selectedArticleID, let itemFrame = timelineItemFrames[articleID] {
 						if itemFrame.minY < proxyFrame.minY + 3 || itemFrame.maxY > proxyFrame.maxY - 3 {
@@ -98,6 +98,12 @@ struct TimelineView: View {
 					}
 				}
 			}
+			.onReceive(timelineModel.timelineItemsPublisher!) { items in
+// Animations crash on iPadOS right now
+//				withAnimation {
+					timelineItems = items
+//				}
+			}
 			.navigationBarTitle(Text(verbatim: timelineModel.nameForDisplay), displayMode: .inline)
 			#endif
 		}

Multiplatform/iOS/Article/ArticleViewController.swift

@@ -61,9 +61,9 @@ class ArticleViewController: UIViewController {
 			view.bottomAnchor.constraint(equalTo: pageViewController.view.bottomAnchor)
 		])
 				
-		selectedArticlesCancellable = sceneModel?.timelineModel.$selectedArticles.sink { [weak self] articles in
-			self?.articles = articles
-		}
+//		selectedArticlesCancellable = sceneModel?.timelineModel.$selectedArticles.sink { [weak self] articles in
+//			self?.articles = articles
+//		}
 		
 		let controller = createWebViewController(currentArticle, updateView: true)
 		self.pageViewController.setViewControllers([controller], direction: .forward, animated: false, completion: nil)