Rewrite Sidebar select next unread in Combine

Multiplatform/Shared/CombineExt/DemandBuffer.swift

@@ -0,0 +1,151 @@
+//
+//  DemandBuffer.swift
+//  CombineExt
+//
+//  Created by Shai Mishali on 21/02/2020.
+//  Copyright © 2020 Combine Community. All rights reserved.
+//
+
+#if canImport(Combine)
+import Combine
+import class Foundation.NSRecursiveLock
+
+/// A buffer responsible for managing the demand of a downstream
+/// subscriber for an upstream publisher
+///
+/// It buffers values and completion events and forwards them dynamically
+/// according to the demand requested by the downstream
+///
+/// In a sense, the subscription only relays the requests for demand, as well
+/// the events emitted by the upstream — to this buffer, which manages
+/// the entire behavior and backpressure contract
+@available(OSX 10.15, iOS 13.0, tvOS 13.0, watchOS 6.0, *)
+class DemandBuffer<S: Subscriber> {
+	private let lock = NSRecursiveLock()
+	private var buffer = [S.Input]()
+	private let subscriber: S
+	private var completion: Subscribers.Completion<S.Failure>?
+	private var demandState = Demand()
+
+	/// Initialize a new demand buffer for a provided downstream subscriber
+	///
+	/// - parameter subscriber: The downstream subscriber demanding events
+	init(subscriber: S) {
+		self.subscriber = subscriber
+	}
+
+	/// Buffer an upstream value to later be forwarded to
+	/// the downstream subscriber, once it demands it
+	///
+	/// - parameter value: Upstream value to buffer
+	///
+	/// - returns: The demand fulfilled by the bufferr
+	func buffer(value: S.Input) -> Subscribers.Demand {
+		precondition(self.completion == nil,
+					 "How could a completed publisher sent values?! Beats me 🤷‍♂️")
+
+		switch demandState.requested {
+		case .unlimited:
+			return subscriber.receive(value)
+		default:
+			buffer.append(value)
+			return flush()
+		}
+	}
+
+	/// Complete the demand buffer with an upstream completion event
+	///
+	/// This method will deplete the buffer immediately,
+	/// based on the currently accumulated demand, and relay the
+	/// completion event down as soon as demand is fulfilled
+	///
+	/// - parameter completion: Completion event
+	func complete(completion: Subscribers.Completion<S.Failure>) {
+		precondition(self.completion == nil,
+					 "Completion have already occured, which is quite awkward 🥺")
+
+		self.completion = completion
+		_ = flush()
+	}
+
+	/// Signal to the buffer that the downstream requested new demand
+	///
+	/// - note: The buffer will attempt to flush as many events rqeuested
+	///         by the downstream at this point
+	func demand(_ demand: Subscribers.Demand) -> Subscribers.Demand {
+		flush(adding: demand)
+	}
+
+	/// Flush buffered events to the downstream based on the current
+	/// state of the downstream's demand
+	///
+	/// - parameter newDemand: The new demand to add. If `nil`, the flush isn't the
+	///                        result of an explicit demand change
+	///
+	/// - note: After fulfilling the downstream's request, if completion
+	///         has already occured, the buffer will be cleared and the
+	///         completion event will be sent to the downstream subscriber
+	private func flush(adding newDemand: Subscribers.Demand? = nil) -> Subscribers.Demand {
+		lock.lock()
+		defer { lock.unlock() }
+
+		if let newDemand = newDemand {
+			demandState.requested += newDemand
+		}
+
+		// If buffer isn't ready for flushing, return immediately
+		guard demandState.requested > 0 || newDemand == Subscribers.Demand.none else { return .none }
+
+		while !buffer.isEmpty && demandState.processed < demandState.requested {
+			demandState.requested += subscriber.receive(buffer.remove(at: 0))
+			demandState.processed += 1
+		}
+
+		if let completion = completion {
+			// Completion event was already sent
+			buffer = []
+			demandState = .init()
+			self.completion = nil
+			subscriber.receive(completion: completion)
+			return .none
+		}
+
+		let sentDemand = demandState.requested - demandState.sent
+		demandState.sent += sentDemand
+		return sentDemand
+	}
+}
+
+// MARK: - Private Helpers
+@available(OSX 10.15, iOS 13.0, tvOS 13.0, watchOS 6.0, *)
+private extension DemandBuffer {
+	/// A model that tracks the downstream's
+	/// accumulated demand state
+	struct Demand {
+		var processed: Subscribers.Demand = .none
+		var requested: Subscribers.Demand = .none
+		var sent: Subscribers.Demand = .none
+	}
+}
+
+// MARK: - Internally-scoped helpers
+@available(OSX 10.15, iOS 13.0, tvOS 13.0, watchOS 6.0, *)
+extension Subscription {
+	/// Reqeust demand if it's not empty
+	///
+	/// - parameter demand: Requested demand
+	func requestIfNeeded(_ demand: Subscribers.Demand) {
+		guard demand > .none else { return }
+		request(demand)
+	}
+}
+
+@available(OSX 10.15, iOS 13.0, tvOS 13.0, watchOS 6.0, *)
+extension Optional where Wrapped == Subscription {
+	/// Cancel the Optional subscription and nullify it
+	mutating func kill() {
+		self?.cancel()
+		self = nil
+	}
+}
+#endif

Multiplatform/Shared/CombineExt/Sink.swift

@@ -0,0 +1,101 @@
+//
+//  Sink.swift
+//  CombineExt
+//
+//  Created by Shai Mishali on 14/03/2020.
+//  Copyright © 2020 Combine Community. All rights reserved.
+//
+
+#if canImport(Combine)
+import Combine
+
+/// A generic sink using an underlying demand buffer to balance
+/// the demand of a downstream subscriber for the events of an
+/// upstream publisher
+@available(OSX 10.15, iOS 13.0, tvOS 13.0, watchOS 6.0, *)
+class Sink<Upstream: Publisher, Downstream: Subscriber>: Subscriber {
+	typealias TransformFailure = (Upstream.Failure) -> Downstream.Failure?
+	typealias TransformOutput = (Upstream.Output) -> Downstream.Input?
+
+	private(set) var buffer: DemandBuffer<Downstream>
+	private var upstreamSubscription: Subscription?
+	private let transformOutput: TransformOutput?
+	private let transformFailure: TransformFailure?
+
+	/// Initialize a new sink subscribing to the upstream publisher and
+	/// fulfilling the demand of the downstream subscriber using a backpresurre
+	/// demand-maintaining buffer.
+	///
+	/// - parameter upstream: The upstream publisher
+	/// - parameter downstream: The downstream subscriber
+	/// - parameter transformOutput: Transform the upstream publisher's output type to the downstream's input type
+	/// - parameter transformFailure: Transform the upstream failure type to the downstream's failure type
+	///
+	/// - note: You **must** provide the two transformation functions above if you're using
+	///         the default `Sink` implementation. Otherwise, you must subclass `Sink` with your own
+	///         publisher's sink and manage the buffer accordingly.
+	init(upstream: Upstream,
+		 downstream: Downstream,
+		 transformOutput: TransformOutput? = nil,
+		 transformFailure: TransformFailure? = nil) {
+		self.buffer = DemandBuffer(subscriber: downstream)
+		self.transformOutput = transformOutput
+		self.transformFailure = transformFailure
+		upstream.subscribe(self)
+	}
+
+	func demand(_ demand: Subscribers.Demand) {
+		let newDemand = buffer.demand(demand)
+		upstreamSubscription?.requestIfNeeded(newDemand)
+	}
+
+	func receive(subscription: Subscription) {
+		upstreamSubscription = subscription
+	}
+
+	func receive(_ input: Upstream.Output) -> Subscribers.Demand {
+		guard let transform = transformOutput else {
+			fatalError("""
+				❌ Missing output transformation
+				=========================
+
+				You must either:
+					- Provide a transformation function from the upstream's output to the downstream's input; or
+					- Subclass `Sink` with your own publisher's Sink and manage the buffer yourself
+			""")
+		}
+
+		guard let input = transform(input) else { return .none }
+		return buffer.buffer(value: input)
+	}
+
+	func receive(completion: Subscribers.Completion<Upstream.Failure>) {
+		switch completion {
+		case .finished:
+			buffer.complete(completion: .finished)
+		case .failure(let error):
+			guard let transform = transformFailure else {
+				fatalError("""
+					❌ Missing failure transformation
+					=========================
+
+					You must either:
+						- Provide a transformation function from the upstream's failure to the downstream's failuer; or
+						- Subclass `Sink` with your own publisher's Sink and manage the buffer yourself
+				""")
+			}
+
+			guard let error = transform(error) else { return }
+			buffer.complete(completion: .failure(error))
+		}
+
+		cancelUpstream()
+	}
+
+	func cancelUpstream() {
+		upstreamSubscription.kill()
+	}
+
+	deinit { cancelUpstream() }
+}
+#endif

Multiplatform/Shared/CombineExt/WIthLatestFrom.swift

@@ -0,0 +1,238 @@
+//
+//  WithLatestFrom.swift
+//  CombineExt
+//
+//  Created by Shai Mishali on 29/08/2019.
+//  Copyright © 2020 Combine Community. All rights reserved.
+//
+
+#if canImport(Combine)
+import Combine
+
+// MARK: - Operator methods
+@available(OSX 10.15, iOS 13.0, tvOS 13.0, watchOS 6.0, *)
+public extension Publisher {
+  ///  Merges two publishers into a single publisher by combining each value
+  ///  from self with the latest value from the second publisher, if any.
+  ///
+  ///  - parameter other: A second publisher source.
+  ///  - parameter resultSelector: Function to invoke for each value from the self combined
+  ///                              with the latest value from the second source, if any.
+  ///
+  ///  - returns: A publisher containing the result of combining each value of the self
+  ///             with the latest value from the second publisher, if any, using the
+  ///             specified result selector function.
+  func withLatestFrom<Other: Publisher, Result>(_ other: Other,
+												resultSelector: @escaping (Output, Other.Output) -> Result)
+	-> Publishers.WithLatestFrom<Self, Other, Result> {
+	  return .init(upstream: self, second: other, resultSelector: resultSelector)
+  }
+
+  ///  Merges three publishers into a single publisher by combining each value
+  ///  from self with the latest value from the second and third publisher, if any.
+  ///
+  ///  - parameter other: A second publisher source.
+  ///  - parameter other1: A third publisher source.
+  ///  - parameter resultSelector: Function to invoke for each value from the self combined
+  ///                              with the latest value from the second and third source, if any.
+  ///
+  ///  - returns: A publisher containing the result of combining each value of the self
+  ///             with the latest value from the second and third publisher, if any, using the
+  ///             specified result selector function.
+  func withLatestFrom<Other: Publisher, Other1: Publisher, Result>(_ other: Other,
+																   _ other1: Other1,
+																   resultSelector: @escaping (Output, (Other.Output, Other1.Output)) -> Result)
+	-> Publishers.WithLatestFrom<Self, AnyPublisher<(Other.Output, Other1.Output), Self.Failure>, Result>
+	where Other.Failure == Failure, Other1.Failure == Failure {
+	  let combined = other.combineLatest(other1)
+		.eraseToAnyPublisher()
+	  return .init(upstream: self, second: combined, resultSelector: resultSelector)
+  }
+
+  ///  Merges four publishers into a single publisher by combining each value
+  ///  from self with the latest value from the second, third and fourth publisher, if any.
+  ///
+  ///  - parameter other: A second publisher source.
+  ///  - parameter other1: A third publisher source.
+  ///  - parameter other2: A fourth publisher source.
+  ///  - parameter resultSelector: Function to invoke for each value from the self combined
+  ///                              with the latest value from the second, third and fourth source, if any.
+  ///
+  ///  - returns: A publisher containing the result of combining each value of the self
+  ///             with the latest value from the second, third and fourth publisher, if any, using the
+  ///             specified result selector function.
+  func withLatestFrom<Other: Publisher, Other1: Publisher, Other2: Publisher, Result>(_ other: Other,
+																					  _ other1: Other1,
+																					  _ other2: Other2,
+																					  resultSelector: @escaping (Output, (Other.Output, Other1.Output, Other2.Output)) -> Result)
+	-> Publishers.WithLatestFrom<Self, AnyPublisher<(Other.Output, Other1.Output, Other2.Output), Self.Failure>, Result>
+	where Other.Failure == Failure, Other1.Failure == Failure, Other2.Failure == Failure {
+	  let combined = other.combineLatest(other1, other2)
+		.eraseToAnyPublisher()
+	  return .init(upstream: self, second: combined, resultSelector: resultSelector)
+  }
+
+  ///  Upon an emission from self, emit the latest value from the
+  ///  second publisher, if any exists.
+  ///
+  ///  - parameter other: A second publisher source.
+  ///
+  ///  - returns: A publisher containing the latest value from the second publisher, if any.
+  func withLatestFrom<Other: Publisher>(_ other: Other)
+	-> Publishers.WithLatestFrom<Self, Other, Other.Output> {
+	  return .init(upstream: self, second: other) { $1 }
+  }
+
+  /// Upon an emission from self, emit the latest value from the
+  /// second and third publisher, if any exists.
+  ///
+  /// - parameter other: A second publisher source.
+  /// - parameter other1: A third publisher source.
+  ///
+  /// - returns: A publisher containing the latest value from the second and third publisher, if any.
+  func withLatestFrom<Other: Publisher, Other1: Publisher>(_ other: Other,
+														   _ other1: Other1)
+	-> Publishers.WithLatestFrom<Self, AnyPublisher<(Other.Output, Other1.Output), Self.Failure>, (Other.Output, Other1.Output)>
+	where Other.Failure == Failure, Other1.Failure == Failure {
+	 withLatestFrom(other, other1) { $1 }
+  }
+
+  /// Upon an emission from self, emit the latest value from the
+  /// second, third and forth publisher, if any exists.
+  ///
+  /// - parameter other: A second publisher source.
+  /// - parameter other1: A third publisher source.
+  /// - parameter other2: A forth publisher source.
+  ///
+  /// - returns: A publisher containing the latest value from the second, third and forth publisher, if any.
+  func withLatestFrom<Other: Publisher, Other1: Publisher, Other2: Publisher>(_ other: Other,
+																			  _ other1: Other1,
+																			  _ other2: Other2)
+	-> Publishers.WithLatestFrom<Self, AnyPublisher<(Other.Output, Other1.Output, Other2.Output), Self.Failure>, (Other.Output, Other1.Output, Other2.Output)>
+	where Other.Failure == Failure, Other1.Failure == Failure, Other2.Failure == Failure {
+	 withLatestFrom(other, other1, other2) { $1 }
+  }
+}
+
+// MARK: - Publisher
+@available(OSX 10.15, iOS 13.0, tvOS 13.0, watchOS 6.0, *)
+public extension Publishers {
+  struct WithLatestFrom<Upstream: Publisher,
+						Other: Publisher,
+						Output>: Publisher where Upstream.Failure == Other.Failure {
+	public typealias Failure = Upstream.Failure
+	public typealias ResultSelector = (Upstream.Output, Other.Output) -> Output
+
+	private let upstream: Upstream
+	private let second: Other
+	private let resultSelector: ResultSelector
+	private var latestValue: Other.Output?
+
+	init(upstream: Upstream,
+		 second: Other,
+		 resultSelector: @escaping ResultSelector) {
+	  self.upstream = upstream
+	  self.second = second
+	  self.resultSelector = resultSelector
+	}
+
+	public func receive<S: Subscriber>(subscriber: S) where Failure == S.Failure, Output == S.Input {
+		subscriber.receive(subscription: Subscription(upstream: upstream,
+													  downstream: subscriber,
+													  second: second,
+													  resultSelector: resultSelector))
+	}
+  }
+}
+
+// MARK: - Subscription
+@available(OSX 10.15, iOS 13.0, tvOS 13.0, watchOS 6.0, *)
+private extension Publishers.WithLatestFrom {
+  class Subscription<Downstream: Subscriber>: Combine.Subscription, CustomStringConvertible where Downstream.Input == Output, Downstream.Failure == Failure {
+	private let resultSelector: ResultSelector
+	private var sink: Sink<Upstream, Downstream>?
+
+	private let upstream: Upstream
+	private let downstream: Downstream
+	private let second: Other
+
+	// Secondary (other) publisher
+	private var latestValue: Other.Output?
+	private var otherSubscription: Cancellable?
+	private var preInitialDemand = Subscribers.Demand.none
+
+	init(upstream: Upstream,
+		 downstream: Downstream,
+		 second: Other,
+		 resultSelector: @escaping ResultSelector) {
+		self.upstream = upstream
+		self.second = second
+		self.downstream = downstream
+		self.resultSelector = resultSelector
+
+		trackLatestFromSecond { [weak self] in
+			guard let self = self else { return }
+			self.request(self.preInitialDemand)
+			self.preInitialDemand = .none
+		}
+	}
+
+	func request(_ demand: Subscribers.Demand) {
+		guard latestValue != nil else {
+			preInitialDemand += demand
+			return
+		}
+
+		self.sink?.demand(demand)
+	}
+
+	// Create an internal subscription to the `Other` publisher,
+	// constantly tracking its latest value
+	private func trackLatestFromSecond(onInitialValue: @escaping () -> Void) {
+	  var gotInitialValue = false
+
+	  let subscriber = AnySubscriber<Other.Output, Other.Failure>(
+		receiveSubscription: { [weak self] subscription in
+			self?.otherSubscription = subscription
+			subscription.request(.unlimited)
+		},
+		receiveValue: { [weak self] value in
+			guard let self = self else { return .none }
+			self.latestValue = value
+
+			if !gotInitialValue {
+				// When getting initial value, start pulling values
+				// from upstream in the main sink
+				self.sink = Sink(upstream: self.upstream,
+								 downstream: self.downstream,
+								 transformOutput: { [weak self] value in
+									guard let self = self,
+										  let other = self.latestValue else { return nil }
+
+									return self.resultSelector(value, other)
+								 },
+								 transformFailure: { $0 })
+
+				// Signal initial value to start fulfilling downstream demand
+				gotInitialValue = true
+				onInitialValue()
+			}
+
+			return .unlimited
+		},
+		receiveCompletion: nil)
+
+	  self.second.subscribe(subscriber)
+	}
+
+	var description: String {
+		return "WithLatestFrom.Subscription<\(Output.self), \(Failure.self)>"
+	}
+
+	func cancel() {
+		sink = nil
+		otherSubscription?.cancel()
+	}
+  }
+}
+#endif

Multiplatform/Shared/SceneModel.swift

@@ -57,7 +57,7 @@ final class SceneModel: ObservableObject {
 	func goToNextUnread() {
 		if !timelineModel.goToNextUnread() {
 			timelineModel.isSelectNextUnread = true
-			sidebarModel.goToNextUnread()
+			sidebarModel.selectNextUnread.send(true)
 		}
 	}
 	

Multiplatform/Shared/Sidebar/SidebarModel.swift

@@ -21,6 +21,7 @@ class SidebarModel: ObservableObject, UndoableCommandRunner {
 	weak var delegate: SidebarModelDelegate?
 
 	var sidebarItemsPublisher: AnyPublisher<[SidebarItem], Never>?
+	var selectNextUnread = PassthroughSubject<Bool, Never>()
 	
 	@Published var selectedFeedIdentifiers = Set<FeedIdentifier>()
 	@Published var selectedFeedIdentifier: FeedIdentifier? = .none
@@ -35,27 +36,16 @@ class SidebarModel: ObservableObject, UndoableCommandRunner {
 	init() {
 		subscribeToSelectedFeedChanges()
 		subscribeToRebuildSidebarItemsEvents()
-	}
+		subscribeToNextUnread()
-
-	// MARK: API
-
-	func goToNextUnread() {
-//		guard let startFeed = selectedFeeds.first ?? sidebarItems.first?.children.first?.feed else { return }
-//
-//		if !goToNextUnread(startingAt: startFeed) {
-//			if let firstFeed = sidebarItems.first?.children.first?.feed {
-//				goToNextUnread(startingAt: firstFeed)
-//			}
-//		}
 	}
 	
 }
 
 // MARK: Side Context Menu Actions
+
 extension SidebarModel {
 	
 	func markAllAsRead(feed: Feed) {
-		
 		var articles = Set<Article>()
 		let fetchedArticles = try! feed.fetchArticles()
 		for article in fetchedArticles {
@@ -190,6 +180,20 @@ private extension SidebarModel {
 			.eraseToAnyPublisher()
 	}
 	
+	func subscribeToNextUnread() {
+		guard let sidebarItemsPublisher = sidebarItemsPublisher else { return }
+
+		selectNextUnread
+			.withLatestFrom(sidebarItemsPublisher, $selectedFeeds)
+			.compactMap { [weak self] (sidebarItems, selectedFeeds) in
+				return self?.nextUnread(sidebarItems: sidebarItems, selectedFeeds: selectedFeeds)
+			}
+			.sink { [weak self] nextFeedID in
+				self?.select(nextFeedID)
+			}
+			.store(in: &cancellables)
+	}
+	
 	// MARK: Sidebar Building
 	
 	func sort(_ folders: Set<Folder>) -> [Folder] {
@@ -254,38 +258,47 @@ private extension SidebarModel {
 		}
 	}
 	
-//	@discardableResult
+	func nextUnread(sidebarItems: [SidebarItem], selectedFeeds: [Feed]) -> FeedIdentifier? {
-//	func goToNextUnread(startingAt: Feed) -> Bool {
+		guard let startFeed = selectedFeeds.first ?? sidebarItems.first?.children.first?.feed else { return nil }
-//
+
-//		var foundStartFeed = false
+		if let feedID = nextUnread(sidebarItems: sidebarItems, startingAt: startFeed) {
-//		var nextSidebarItem: SidebarItem? = nil
+			return feedID
-//		for section in sidebarItems {
+		} else {
-//			if nextSidebarItem == nil  {
+			if let firstFeed = sidebarItems.first?.children.first?.feed {
-//				section.visit { sidebarItem in
+				return nextUnread(sidebarItems: sidebarItems, startingAt: firstFeed)
-//					if !foundStartFeed && sidebarItem.feed?.feedID == startingAt.feedID {
+			}
-//						foundStartFeed = true
+		}
-//						return false
+		
-//					}
+		return nil
-//					if foundStartFeed && sidebarItem.unreadCount > 0 {
+	}
-//						nextSidebarItem = sidebarItem
+	
-//						return true
+	@discardableResult
-//					}
+	func nextUnread(sidebarItems: [SidebarItem], startingAt: Feed) -> FeedIdentifier? {
-//					return false
+		var foundStartFeed = false
-//				}
+		var nextSidebarItem: SidebarItem? = nil
-//			}
+		
-//		}
+		for section in sidebarItems {
-//
+			if nextSidebarItem == nil  {
-//		if let nextFeedID = nextSidebarItem?.feed?.feedID {
+				section.visit { sidebarItem in
-//			select(nextFeedID)
+					if !foundStartFeed && sidebarItem.feed?.feedID == startingAt.feedID {
-//			return true
+						foundStartFeed = true
-//		}
+						return false
-//
+					}
-//		return false
+					if foundStartFeed && sidebarItem.unreadCount > 0 {
-//	}
+						nextSidebarItem = sidebarItem
-//
+						return true
-//	func select(_ feedID: FeedIdentifier) {
+					}
-//		selectedFeedIdentifiers = Set([feedID])
+					return false
-//		selectedFeedIdentifier = feedID
+				}
-//	}
+			}
+		}
+
+		return nextSidebarItem?.feed?.feedID
+	}
+
+	func select(_ feedID: FeedIdentifier) {
+		selectedFeedIdentifiers = Set([feedID])
+		selectedFeedIdentifier = feedID
+	}
 	
 }

NetNewsWire.xcodeproj/project.pbxproj

@@ -332,6 +332,12 @@
 		51A5769624AE617200078888 /* ArticleContainerView.swift in Sources */ = {isa = PBXBuildFile; fileRef = 51A5769524AE617200078888 /* ArticleContainerView.swift */; };
 		51A5769724AE617200078888 /* ArticleContainerView.swift in Sources */ = {isa = PBXBuildFile; fileRef = 51A5769524AE617200078888 /* ArticleContainerView.swift */; };
 		51A66685238075AE00CB272D /* AddWebFeedDefaultContainer.swift in Sources */ = {isa = PBXBuildFile; fileRef = 51A66684238075AE00CB272D /* AddWebFeedDefaultContainer.swift */; };
+		51A8001224CA0FC700F41F1D /* Sink.swift in Sources */ = {isa = PBXBuildFile; fileRef = 51A8001124CA0FC700F41F1D /* Sink.swift */; };
+		51A8001324CA0FC700F41F1D /* Sink.swift in Sources */ = {isa = PBXBuildFile; fileRef = 51A8001124CA0FC700F41F1D /* Sink.swift */; };
+		51A8001524CA0FEC00F41F1D /* DemandBuffer.swift in Sources */ = {isa = PBXBuildFile; fileRef = 51A8001424CA0FEC00F41F1D /* DemandBuffer.swift */; };
+		51A8001624CA0FEC00F41F1D /* DemandBuffer.swift in Sources */ = {isa = PBXBuildFile; fileRef = 51A8001424CA0FEC00F41F1D /* DemandBuffer.swift */; };
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 		51A66684238075AE00CB272D /* AddWebFeedDefaultContainer.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AddWebFeedDefaultContainer.swift; sourceTree = "<group>"; };
+		51A8001124CA0FC700F41F1D /* Sink.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Sink.swift; sourceTree = "<group>"; };
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+		51A8FFEC24CA0CF400F41F1D /* WIthLatestFrom.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = WIthLatestFrom.swift; sourceTree = "<group>"; };
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@@ -3016,6 +3025,16 @@
 			path = Article;
 			sourceTree = "<group>";
 		};
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+			sourceTree = "<group>";
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@@ -3080,6 +3099,7 @@
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 				17930ED224AF10CD00A9BA52 /* Add */,
 				51A576B924AE617B00078888 /* Article */,
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 					513C5CE5232571C2003D4054 = {
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 					51C0513C24A77DF800194D5E = {
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-						DevelopmentTeam = FQLBNX3GP7;
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 					6581C73220CED60000F4AD34 = {
-						DevelopmentTeam = FQLBNX3GP7;
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 					65ED3FA2235DEF6C0081F399 = {
-						DevelopmentTeam = FQLBNX3GP7;
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 						ProvisioningStyle = Automatic;
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 					65ED4090235DEF770081F399 = {
-						DevelopmentTeam = FQLBNX3GP7;
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 						CreatedOnToolsVersion = 9.3;
-						DevelopmentTeam = FQLBNX3GP7;
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@@ -4346,7 +4366,7 @@
 					};
 					849C645F1ED37A5D003D8FC0 = {
 						CreatedOnToolsVersion = 8.2.1;
-						DevelopmentTeam = FQLBNX3GP7;
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@@ -4356,7 +4376,7 @@
 					};
 					849C64701ED37A5D003D8FC0 = {
 						CreatedOnToolsVersion = 8.2.1;
-						DevelopmentTeam = FQLBNX3GP7;
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 						TestTargetID = 849C645F1ED37A5D003D8FC0;
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@@ -5174,6 +5194,7 @@
 				65082A5424C73D2F009FA994 /* AccountCredentialsError.swift in Sources */,
 				51E4990B24A808C500B667CB /* ImageDownloader.swift in Sources */,
 				51E498F424A8085D00B667CB /* SmartFeedDelegate.swift in Sources */,
+				51A8001524CA0FEC00F41F1D /* DemandBuffer.swift in Sources */,
 				514E6BFF24AD255D00AC6F6E /* PreviewArticles.swift in Sources */,
 				51E4993024A8676400B667CB /* ArticleSorter.swift in Sources */,
 				51408B7E24A9EC6F0073CF4E /* SidebarItem.swift in Sources */,
@@ -5196,6 +5217,7 @@
 				51E4990124A808BB00B667CB /* FaviconURLFinder.swift in Sources */,
 				51E4991D24A8092100B667CB /* NSAttributedString+NetNewsWire.swift in Sources */,
 				65082A2F24C72AC8009FA994 /* SettingsCredentialsAccountView.swift in Sources */,
+				51A8FFED24CA0CF400F41F1D /* WIthLatestFrom.swift in Sources */,
 				51E499FD24A9137600B667CB /* SidebarModel.swift in Sources */,
 				5181C66224B0C326002E0F70 /* SettingsModel.swift in Sources */,
 				51E4995324A8734D00B667CB /* RedditFeedProvider-Extensions.swift in Sources */,
@@ -5248,6 +5270,7 @@
 				5177472224B38CAE00EB0F74 /* ArticleExtractorButtonState.swift in Sources */,
 				5177471A24B3863000EB0F74 /* WebViewProvider.swift in Sources */,
 				51E4992124A8095000B667CB /* RSImage-Extensions.swift in Sources */,
+				51A8001224CA0FC700F41F1D /* Sink.swift in Sources */,
 				51E4990324A808BB00B667CB /* FaviconDownloader.swift in Sources */,
 				172199ED24AB2E0100A31D04 /* SafariView.swift in Sources */,
 				65ACE48624B477C9003AE06A /* SettingsAccountLabelView.swift in Sources */,
@@ -5284,11 +5307,13 @@
 				51B8BCC324C25C3E00360B00 /* SidebarContextMenu.swift in Sources */,
 				51E498C724A8085D00B667CB /* StarredFeedDelegate.swift in Sources */,
 				5194736F24BBB937001A2939 /* HiddenModifier.swift in Sources */,
+				51A8001624CA0FEC00F41F1D /* DemandBuffer.swift in Sources */,
 				51919FB724AABCA100541E64 /* IconImageView.swift in Sources */,
 				51B54A6924B54A490014348B /* IconView.swift in Sources */,
 				17897ACB24C281A40014BA03 /* InspectorView.swift in Sources */,
 				51E498FA24A808BA00B667CB /* SingleFaviconDownloader.swift in Sources */,
 				1727B39924C1368D00A4DBDC /* LayoutPreferencesView.swift in Sources */,
+				51A8FFEE24CA0CF400F41F1D /* WIthLatestFrom.swift in Sources */,
 				51E4993F24A8713B00B667CB /* ArticleStatusSyncTimer.swift in Sources */,
 				51E4993724A8680E00B667CB /* Reachability.swift in Sources */,
 				51B80F4424BE58BF00C6C32D /* SharingServiceDelegate.swift in Sources */,
@@ -5407,6 +5432,7 @@
 				1769E32724BC5B6C000E1E8E /* AddAccountModel.swift in Sources */,
 				1729529424AA1CAA00D65E66 /* AdvancedPreferencesView.swift in Sources */,
 				5177470424B2657F00EB0F74 /* TimelineToolbarModifier.swift in Sources */,
+				51A8001324CA0FC700F41F1D /* Sink.swift in Sources */,
 				51E4992D24A8676300B667CB /* FetchRequestOperation.swift in Sources */,
 				51E4992424A8098400B667CB /* SmartFeedPasteboardWriter.swift in Sources */,
 				51E4991424A808FF00B667CB /* ArticleStringFormatter.swift in Sources */,