Prevent race in status action account list

Prevents CoreData warnings when switching accounts and constructing a
second MastodonCachePersistentStore

Tusker.xcodeproj/project.pbxproj

@@ -158,6 +158,7 @@
 		D6757A7E2157E02600721E32 /* XCBRequestSpec.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6757A7D2157E02600721E32 /* XCBRequestSpec.swift */; };
 		D6757A822157E8FA00721E32 /* XCBSession.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6757A812157E8FA00721E32 /* XCBSession.swift */; };
 		D67895BC24671E6D00D4CD9E /* PKDrawing+Render.swift in Sources */ = {isa = PBXBuildFile; fileRef = D67895BB24671E6D00D4CD9E /* PKDrawing+Render.swift */; };
+		D67895C0246870DE00D4CD9E /* LocalAccountAvatarView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D67895BF246870DE00D4CD9E /* LocalAccountAvatarView.swift */; };
 		D679C09F215850EF00DA27FE /* XCBActions.swift in Sources */ = {isa = PBXBuildFile; fileRef = D679C09E215850EF00DA27FE /* XCBActions.swift */; };
 		D67C57AD21E265FC00C3118B /* LargeAccountDetailView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D67C57AC21E265FC00C3118B /* LargeAccountDetailView.swift */; };
 		D67C57AF21E28EAD00C3118B /* Array+Uniques.swift in Sources */ = {isa = PBXBuildFile; fileRef = D67C57AE21E28EAD00C3118B /* Array+Uniques.swift */; };
@@ -454,6 +455,7 @@
 		D6757A7D2157E02600721E32 /* XCBRequestSpec.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = XCBRequestSpec.swift; sourceTree = "<group>"; };
 		D6757A812157E8FA00721E32 /* XCBSession.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = XCBSession.swift; sourceTree = "<group>"; };
 		D67895BB24671E6D00D4CD9E /* PKDrawing+Render.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "PKDrawing+Render.swift"; sourceTree = "<group>"; };
+		D67895BF246870DE00D4CD9E /* LocalAccountAvatarView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = LocalAccountAvatarView.swift; sourceTree = "<group>"; };
 		D679C09E215850EF00DA27FE /* XCBActions.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = XCBActions.swift; sourceTree = "<group>"; };
 		D67C57AC21E265FC00C3118B /* LargeAccountDetailView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = LargeAccountDetailView.swift; sourceTree = "<group>"; };
 		D67C57AE21E28EAD00C3118B /* Array+Uniques.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "Array+Uniques.swift"; sourceTree = "<group>"; };
@@ -942,6 +944,7 @@
 				D6BC9DB2232D4C07002CA326 /* WellnessPrefsView.swift */,
 				0427033922B31269000D31B6 /* AdvancedPrefsView.swift */,
 				0427037B22B316B9000D31B6 /* SilentActionPrefs.swift */,
+				D67895BF246870DE00D4CD9E /* LocalAccountAvatarView.swift */,
 			);
 			path = Preferences;
 			sourceTree = "<group>";
@@ -1743,6 +1746,7 @@
 				D641C77F213DC78A004B4513 /* InlineTextAttachment.swift in Sources */,
 				D627943523A5525100D38C68 /* StatusActivity.swift in Sources */,
 				D663626C21361C6700C9CBA2 /* Account+Preferences.swift in Sources */,
+				D67895C0246870DE00D4CD9E /* LocalAccountAvatarView.swift in Sources */,
 				D6333B372137838300CE884A /* AttributedString+Helpers.swift in Sources */,
 				D6DFC69E242C490400ACC392 /* TrackpadScrollGestureRecognizer.swift in Sources */,
 				D61AC1D8232EA42D00C54D2D /* InstanceTableViewCell.swift in Sources */,

Tusker/CoreData/MastodonCachePersistentStore.swift

@@ -13,15 +13,18 @@ import Combine
 
 class MastodonCachePersistentStore: NSPersistentContainer {
     
+    private static let managedObjectModel: NSManagedObjectModel = {
+        let url = Bundle.main.url(forResource: "Tusker", withExtension: "momd")!
+        return NSManagedObjectModel(contentsOf: url)!
+    }()
+    
     private(set) lazy var backgroundContext = newBackgroundContext()
     
     let statusSubject = PassthroughSubject<String, Never>()
     let accountSubject = PassthroughSubject<String, Never>()
     
     init(for controller: MastodonController) {
-        let url = Bundle.main.url(forResource: "Tusker", withExtension: "momd")!
-        let model = NSManagedObjectModel(contentsOf: url)!
-        super.init(name: "\(controller.accountInfo!.id)_cache", managedObjectModel: model)
+        super.init(name: "\(controller.accountInfo!.id)_cache", managedObjectModel: MastodonCachePersistentStore.managedObjectModel)
         loadPersistentStores { (description, error) in
             if let error = error {
                 fatalError("Unable to load persistent store: \(error)")

Tusker/Screens/Notifications/NotificationsTableViewController.swift

@@ -127,6 +127,33 @@ class NotificationsTableViewController: EnhancedTableViewController {
     // MARK: - Table view delegate
 
     override func tableView(_ tableView: UITableView, willDisplay cell: UITableViewCell, forRowAt indexPath: IndexPath) {
+        // see TimelineTableViewController.tableView(_:willDisplay:forRowAt:)
+        if !isCurrentlyScrollingToTop, scrollViewDirection < 0 {
+            let pageSize = 20
+            if groups.count > 2 * pageSize,
+                indexPath.row < groups.count - (2 * pageSize) {
+                let groupsToRemove = groups[groups.count - pageSize..<groups.count]
+                for group in groupsToRemove {
+                    for notification in group.notifications {
+                        // todo: reference count accounts
+//                        mastodonController.persistentContainer.account(for: notification.account.id)?.decrementReferenceCount()
+                        if let id = notification.status?.id {
+                            mastodonController.persistentContainer.status(for: id)?.decrementReferenceCount()
+                        }
+                    }
+                }
+                let removedIndexPaths = (groups.count - 20..<groups.count).map { IndexPath(row: $0, section: 0) }
+                
+                groups.removeLast(pageSize)
+                
+                DispatchQueue.main.async {
+                    UIView.performWithoutAnimation {
+                        tableView.deleteRows(at: removedIndexPaths, with: .none)
+                    }
+                }
+            }
+        }
+        
         if indexPath.row == groups.count - 1 {
             guard let older = older else { return }
             

Tusker/Screens/Onboarding/OnboardingViewController.swift

@@ -68,13 +68,16 @@ extension OnboardingViewController: InstanceSelectorTableViewControllerDelegate
                     let authCode = item.value else { return }
                 
                 mastodonController.authorize(authorizationCode: authCode) { (accessToken) in
-                    let accountInfo = LocalData.shared.addAccount(instanceURL: instanceURL, clientID: clientID, clientSecret: clientSecret, username: nil, accessToken: accessToken)
-                    mastodonController.accountInfo = accountInfo
+                    // construct a temporary UserAccountInfo instance for the MastodonController to use to fetch it's own account
+                    let tempAccountInfo = LocalData.UserAccountInfo(id: "temp", instanceURL: instanceURL, clientID: clientID, clientSecret: clientSecret, username: nil, accessToken: accessToken)
+                    mastodonController.accountInfo = tempAccountInfo
                     
                     mastodonController.getOwnAccount { (account) in
-                        LocalData.shared.setUsername(for: accountInfo, username: account.username)
-                        
                         DispatchQueue.main.async {
+                            // this needs to happen on the main thread because it publishes a new value for the ObservableObject
+                            let accountInfo = LocalData.shared.addAccount(instanceURL: instanceURL, clientID: clientID, clientSecret: clientSecret, username: account.username, accessToken: accessToken)
+                            mastodonController.accountInfo = accountInfo
+                            
                             self.onboardingDelegate?.didFinishOnboarding(account: accountInfo)
                         }
                     }

Tusker/Screens/Preferences/LocalAccountAvatarView.swift

@@ -0,0 +1,47 @@
+//
+//  LocalAccountAvatarView.swift
+//  Tusker
+//
+//  Created by Shadowfacts on 5/10/20.
+//  Copyright © 2020 Shadowfacts. All rights reserved.
+//
+
+import SwiftUI
+
+struct LocalAccountAvatarView: View {
+    let localAccountInfo: LocalData.UserAccountInfo
+    @State
+    var avatarImage: UIImage? = nil
+    
+    var body: some View {
+        let image: Image
+        if avatarImage == nil {
+            image = Image(systemName: "person.crop.square")
+        } else {
+            image = Image(uiImage: self.avatarImage!).renderingMode(.original)
+        }
+        return image
+            .resizable()
+            .frame(width: 30, height: 30)
+            .onAppear(perform: self.loadImage)
+    }
+    
+    func loadImage() {
+        let controller = MastodonController.getForAccount(localAccountInfo)
+        controller.getOwnAccount { (account) in
+            _ = ImageCache.avatars.get(account.avatar) { (data) in
+                if let data = data, let image = UIImage(data: data) {
+                    DispatchQueue.main.async {
+                        self.avatarImage = image
+                    }
+                }
+            }
+        }
+    }
+}
+
+//struct LocalAccountAvatarView_Previews: PreviewProvider {
+//    static var previews: some View {
+//        LocalAccountAvatarView()
+//    }
+//}

Tusker/Screens/Preferences/PreferencesView.swift

@@ -21,8 +21,14 @@ struct PreferencesView: View {
                             NotificationCenter.default.post(name: .activateAccount, object: nil, userInfo: ["account": account])
                         }) {
                             HStack {
-                                Text(account.username)
-                                    .foregroundColor(.primary)
+                                LocalAccountAvatarView(localAccountInfo: account)
+                                VStack(alignment: .leading) {
+                                    Text(verbatim: account.username)
+                                        .foregroundColor(.primary)
+                                    Text(verbatim: account.instanceURL.host!)
+                                        .font(.caption)
+                                        .foregroundColor(.primary)
+                                }
                                 Spacer()
                                 if account == self.localData.getMostRecentAccount() {
                                     Image(systemName: "checkmark")

Tusker/Screens/Status Action Account List/StatusActionAccountListTableViewController.swift

@@ -82,10 +82,11 @@ class StatusActionAccountListTableViewController: EnhancedTableViewController {
             let request = actionType == .favorite ? Status.getFavourites(status.id) : Status.getReblogs(status.id)
             mastodonController.run(request) { (response) in
                 guard case let .success(accounts, _) = response else { fatalError() }
-                self.mastodonController.persistentContainer.addAll(accounts: accounts)
-                DispatchQueue.main.async {
-                    self.accountIDs = accounts.map { $0.id }
-                    self.tableView.tableFooterView = nil
+                self.mastodonController.persistentContainer.addAll(accounts: accounts) {
+                    DispatchQueue.main.async {
+                        self.accountIDs = accounts.map { $0.id }
+                        self.tableView.tableFooterView = nil
+                    }
                 }
             }
         }

Tusker/Screens/Timeline/TimelineTableViewController.swift

@@ -19,9 +19,6 @@ class TimelineTableViewController: EnhancedTableViewController {
     var newer: RequestRange?
     var older: RequestRange?
     
-    private var prevScrollViewContentOffset: CGPoint?
-    private var scrollViewDirection: CGFloat = 0
-    
     init(for timeline: Timeline, mastodonController: MastodonController) {
         self.timeline = timeline
         self.mastodonController = mastodonController
@@ -109,8 +106,9 @@ class TimelineTableViewController: EnhancedTableViewController {
     // MARK: - Table view delegate
     
     override func tableView(_ tableView: UITableView, willDisplay cell: UITableViewCell, forRowAt indexPath: IndexPath) {
+        // don't remove rows when jumping to the top, otherwise jumping back down might try to show removed rows
         // when scrolling upwards, decrement reference counts for old statuses, if necessary
-        if scrollViewDirection < 0 {
+        if !isCurrentlyScrollingToTop, scrollViewDirection < 0 {
             if indexPath.section <= timelineSegments.count - 2 {
                 // decrement ref counts for all sections below the section below the current section
                 // (e.g., there exist sections 0, 1, 2 and we're currently scrolling upwards in section 0, we want to remove section 2)
@@ -142,7 +140,7 @@ class TimelineTableViewController: EnhancedTableViewController {
                     for (id, _) in statusesToRemove {
                         mastodonController.persistentContainer.status(for: id)?.decrementReferenceCount()
                     }
-                    timelineSegments[timelineSegments.count - 1].removeLast(20)
+                    timelineSegments[timelineSegments.count - 1].removeLast(pageSize)
                     
                     let removedIndexPaths = (lastSection.count - 20..<lastSection.count).map { IndexPath(row: $0, section: timelineSegments.count - 1) }
                     // Removing this DispatchQueue.main.async call causes things to break when scrolling
@@ -196,6 +194,8 @@ class TimelineTableViewController: EnhancedTableViewController {
         return (tableView.cellForRow(at: indexPath) as? TableViewSwipeActionProvider)?.trailingSwipeActionsConfiguration()
     }
     
+    // MARK: Interaction
+    
     @objc func refreshStatuses(_ sender: Any) {
         guard let newer = newer else { return }
         
@@ -226,15 +226,6 @@ class TimelineTableViewController: EnhancedTableViewController {
             }
         }
     }
-    
-    // Mark: Scroll View Delegate
-    override func scrollViewDidScroll(_ scrollView: UIScrollView) {
-        if let prev = prevScrollViewContentOffset {
-            scrollViewDirection = scrollView.contentOffset.y - prev.y
-        }
-        prevScrollViewContentOffset = scrollView.contentOffset
-    }
-    
 
     @objc func composePressed(_ sender: Any) {
         compose()

Tusker/Screens/Utilities/EnhancedTableViewController.swift

@@ -11,32 +11,45 @@ import SafariServices
 
 class EnhancedTableViewController: UITableViewController {
 
-    var prevScrollToTopOffset: CGPoint? = nil
-
-    private var topOffset: CGPoint {
-        // when scrolled to top, the content offset is negative the height of the UI above the scroll view (i.e. the nav and status bars)
-        let windowScene = view.window!.windowScene!
-        let barOffset = -1 * (navigationController!.navigationBar.frame.height + windowScene.statusBarManager!.statusBarFrame.height)
-        // add one so it's not technically all the way at the top, and scrollViewWShouldScrollToTop is still called to trigger undo
-        return CGPoint(x: 0, y: barOffset + 1)
-    }
+    private var prevScrollToTopOffset: CGPoint? = nil
+    private(set) var isCurrentlyScrollingToTop = false
+    private var prevScrollViewContentOffset: CGPoint?
+    private(set) var scrollViewDirection: CGFloat = 0
+    
+    // MARK: Scroll View Delegate
 
     override func scrollViewShouldScrollToTop(_ scrollView: UIScrollView) -> Bool {
         if let offset = prevScrollToTopOffset {
             tableView.setContentOffset(offset, animated: true)
             prevScrollToTopOffset = nil
+            return false
         } else {
             prevScrollToTopOffset = tableView.contentOffset
-            tableView.setContentOffset(topOffset, animated: true)
+            isCurrentlyScrollingToTop = true
+            return true
         }
-        return false
+    }
+    
+    override func scrollViewDidScrollToTop(_ scrollView: UIScrollView) {
+        isCurrentlyScrollingToTop = false
+        // add one so it's not technically scrolled all the way to the top,
+        // otherwise there's no way of detecting a status bar press to scroll back down
+        tableView.contentOffset.y -= 0.5
     }
 
     override func scrollViewWillBeginDragging(_ scrollView: UIScrollView) {
         prevScrollToTopOffset = nil
     }
     
+    override func scrollViewDidScroll(_ scrollView: UIScrollView) {
+        if let prev = prevScrollViewContentOffset {
+            scrollViewDirection = scrollView.contentOffset.y - prev.y
+        }
+        prevScrollViewContentOffset = scrollView.contentOffset
+    }
     
+    // MARK: Table View Delegate
+
     override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
         if let cell = tableView.cellForRow(at: indexPath) as? SelectableTableViewCell {
             cell.didSelectCell()