Tusker/Caching/ImageCache.swift

@@ -24,7 +24,7 @@ class ImageCache {
     private let cache: ImageDataCache
     private let desiredPixelSize: CGSize?
     
-    private var groups = MultiThreadDictionary<URL, RequestGroup>()
+    private var groups = MultiThreadDictionary<URL, RequestGroup>(name: "ImageCache request groups")
     
     private var backgroundQueue = DispatchQueue(label: "ImageCache completion queue", qos: .default)
     
@@ -96,7 +96,7 @@ class ImageCache {
             if let data = data {
                 try? self.cache.set(url.absoluteString, data: data, image: image)
             }
-            _ = self.groups.removeValue(forKey: url)
+            self.groups.removeValueWithoutReturning(forKey: url)
         }
         groups[url] = group
         return group

Tusker/CoreData/MastodonCachePersistentStore.swift

@@ -20,15 +20,13 @@ class MastodonCachePersistentStore: NSPersistentContainer {
     
     private(set) lazy var backgroundContext: NSManagedObjectContext = {
         let context = NSManagedObjectContext(concurrencyType: .privateQueueConcurrencyType)
-        context.persistentStoreCoordinator = self.persistentStoreCoordinator
-        context.automaticallyMergesChangesFromParent = true
+        context.parent = self.viewContext
         return context
     }()
     
     private(set) lazy var prefetchBackgroundContext: NSManagedObjectContext = {
         let context = NSManagedObjectContext(concurrencyType: .privateQueueConcurrencyType)
-        context.persistentStoreCoordinator = self.persistentStoreCoordinator
-        context.automaticallyMergesChangesFromParent = true
+        context.parent = self.viewContext
         return context
     }()
     
@@ -53,8 +51,6 @@ class MastodonCachePersistentStore: NSPersistentContainer {
             }
         }
         
-        viewContext.automaticallyMergesChangesFromParent = true
-        
         NotificationCenter.default.addObserver(self, selector: #selector(managedObjectsDidChange), name: .NSManagedObjectContextObjectsDidChange, object: viewContext)
     }
     

Tusker/MultiThreadDictionary.swift

@@ -7,79 +7,52 @@
 //
 
 import Foundation
-import os
 
-// once we target iOS 16, replace uses of this with OSAllocatedUnfairLock<[Key: Value]>
-// to make the lock semantics more clear
-@available(iOS, obsoleted: 16.0)
-class MultiThreadDictionary<Key: Hashable & Sendable, Value: Sendable> {
-    private let lock: any Lock<[Key: Value]>
+class MultiThreadDictionary<Key: Hashable, Value> {
+    private let name: String
+    private var dict = [Key: Value]()
+    private let queue: DispatchQueue
     
-    init() {
-        if #available(iOS 16.0, *) {
-            self.lock = OSAllocatedUnfairLock(initialState: [:])
-        } else {
-            self.lock = UnfairLock(initialState: [:])
-        }
+    init(name: String) {
+        self.name = name
+        self.queue = DispatchQueue(label: "MultiThreadDictionary (\(name)) Coordinator", attributes: .concurrent)
     }
     
     subscript(key: Key) -> Value? {
         get {
-            return lock.withLock { dict in
-                dict[key]
+            var result: Value? = nil
+            queue.sync {
+                result = dict[key]
             }
+            return result
         }
         set(value) {
-            lock.withLock { dict in
-                dict[key] = value
+            queue.async(flags: .barrier) {
+                self.dict[key] = value
             }
         }
     }
     
+    func removeValueWithoutReturning(forKey key: Key) {
+        queue.async(flags: .barrier) {
+            self.dict.removeValue(forKey: key)
+        }
+    }
+    
     /// If the result of this function is unused, it is preferable to use `removeValueWithoutReturning` as it executes asynchronously and doesn't block the calling thread.
     func removeValue(forKey key: Key) -> Value? {
-        return lock.withLock { dict in
-            dict.removeValue(forKey: key)
+        var value: Value? = nil
+        queue.sync(flags: .barrier) {
+            value = dict.removeValue(forKey: key)
         }
+        return value
     }
     
     func contains(key: Key) -> Bool {
-        return lock.withLock { dict in
-            dict.keys.contains(key)
+        var value: Bool!
+        queue.sync {
+            value = dict.keys.contains(key)
         }
-    }
-    
-    func withLock<R>(_ body: @Sendable (inout [Key: Value]) throws -> R) rethrows -> R where R: Sendable {
-        return try lock.withLock(body)
-    }
-}
-
-// TODO: replace this only with OSAllocatedUnfairLock
-@available(iOS, obsoleted: 16.0)
-fileprivate protocol Lock<State> {
-    associatedtype State
-    func withLock<R>(_ body: @Sendable (inout State) throws -> R) rethrows -> R where R: Sendable
-}
-
-@available(iOS 16.0, *)
-extension OSAllocatedUnfairLock: Lock {
-}
-
-// from http://www.russbishop.net/the-law
-fileprivate class UnfairLock<State>: Lock {
-    private var lock: UnsafeMutablePointer<os_unfair_lock>
-    private var state: State
-    init(initialState: State) {
-        self.state = initialState
-        self.lock = .allocate(capacity: 1)
-        self.lock.initialize(to: os_unfair_lock())
-    }
-    deinit {
-        self.lock.deallocate()
-    }
-    func withLock<R>(_ body: (inout State) throws -> R) rethrows -> R where R: Sendable {
-        os_unfair_lock_lock(lock)
-        defer { os_unfair_lock_unlock(lock) }
-        return try body(&state)
+        return value
     }
 }

Tusker/Screens/Explore/FeaturedProfileCollectionViewCell.swift

@@ -52,7 +52,7 @@ class FeaturedProfileCollectionViewCell: UICollectionViewCell {
         displayNameLabel.updateForAccountDisplayName(account: account)
         
         noteTextView.setTextFromHtml(account.note)
-        noteTextView.setEmojis(account.emojis, identifier: account.id)
+        noteTextView.setEmojis(account.emojis)
         
         avatarImageView.image = nil
         if let avatar = account.avatar {

Tusker/Views/AccountDisplayNameLabel.swift

@@ -36,7 +36,7 @@ struct AccountDisplayNameLabel<Account: AccountProtocol>: View {
         let matches = emojiRegex.matches(in: account.displayName, options: [], range: fullRange)
         guard !matches.isEmpty else { return }
         
-        let emojiImages = MultiThreadDictionary<String, Image>()
+        let emojiImages = MultiThreadDictionary<String, Image>(name: "AcccountDisplayNameLabel Emoji Images")
         
         let group = DispatchGroup()
         

Tusker/Views/BaseEmojiLabel.swift

@@ -24,7 +24,6 @@ extension BaseEmojiLabel {
         // blergh
         precondition(Thread.isMainThread)
         
-        emojiIdentifier = identifier
         emojiRequests.forEach { $0.cancel() }
         emojiRequests = []
         
@@ -39,7 +38,10 @@ extension BaseEmojiLabel {
             return
         }
         
-        let emojiImages = MultiThreadDictionary<String, UIImage>()
+        // not using a MultiThreadDictionary so that cached images can be added immediately
+        // without jumping through various queues so that we can use them immediately
+        // in building either the final string or the string with placeholders
+        var emojiImages: [String: UIImage] = [:]
         var foundEmojis = false
         
         let group = DispatchGroup()
@@ -69,9 +71,13 @@ extension BaseEmojiLabel {
                               group.leave()
                               return
                     }
+                    // sync back to the main thread to add the dictionary
+                    // todo: using the main thread for this isn't great
+                    DispatchQueue.main.async {
                         emojiImages[emoji.shortcode] = transformedImage
                         group.leave()
                     }
+                }
                 if let request = request {
                     emojiRequests.append(request)
                 }
@@ -86,11 +92,6 @@ extension BaseEmojiLabel {
         func buildStringWithEmojisReplaced(usePlaceholders: Bool) -> NSAttributedString {
             let mutAttrString = NSMutableAttributedString(attributedString: attributedString)
             
-            // lock once for the entire loop, rather than lock/unlocking for each iteration to do the lookup
-            // OSAllocatedUnfairLock.withLock expects a @Sendable closure, so this warns about captures of non-sendable types (attribute dstrings, text checking results)
-            // even though the closures is invoked on the same thread that withLock is called, so it's unclear why it needs to be @Sendable (FB11494878)
-            // so, just ignore the warnings
-            emojiImages.withLock { emojiImages in
             // replaces the emojis starting from the end of the string as to not alter the indices of preceeding emojis
             for match in matches.reversed() {
                 let shortcode = (attributedString.string as NSString).substring(with: match.range(at: 1))
@@ -107,7 +108,6 @@ extension BaseEmojiLabel {
                 let attachmentStr = NSAttributedString(attachment: attachment)
                 mutAttrString.replaceCharacters(in: match.range, with: attachmentStr)
             }
-            }
             
             return mutAttrString
         }

Tusker/Views/ContentTextView.swift

@@ -57,8 +57,8 @@ class ContentTextView: LinkTextView, BaseEmojiLabel {
     }
     
     // MARK: - Emojis
-    func setEmojis(_ emojis: [Emoji], identifier: String?) {
-        replaceEmojis(in: attributedText!, emojis: emojis, identifier: identifier) { attributedString, didReplaceEmojis in
+    func setEmojis(_ emojis: [Emoji]) {
+        replaceEmojis(in: attributedText!, emojis: emojis, identifier: emojiIdentifier) { attributedString, didReplaceEmojis in
             guard didReplaceEmojis else {
                 return
             }

Tusker/Views/EmojiLabel.swift

@@ -21,9 +21,13 @@ class EmojiLabel: UILabel, BaseEmojiLabel {
     func setEmojis(_ emojis: [Emoji], identifier: String) {
         guard emojis.count > 0, let attributedText = attributedText else { return }
 
-        replaceEmojis(in: attributedText.string, emojis: emojis, identifier: identifier) { [weak self] (newAttributedText, didReplaceEmojis) in
+        self.emojiIdentifier = identifier
+        emojiRequests.forEach { $0.cancel() }
+        emojiRequests = []
+        hasEmojis = true
+        
+        replaceEmojis(in: attributedText.string, emojis: emojis, identifier: identifier) { [weak self] (newAttributedText, _) in
             guard let self = self, self.emojiIdentifier == identifier else { return }
-            self.hasEmojis = didReplaceEmojis
             self.attributedText = newAttributedText
             self.setNeedsLayout()
             self.setNeedsDisplay()

Tusker/Views/Profile Header/ProfileHeaderView.swift

@@ -110,7 +110,7 @@ class ProfileHeaderView: UIView {
         
         noteTextView.navigationDelegate = delegate
         noteTextView.setTextFromHtml(account.note)
-        noteTextView.setEmojis(account.emojis, identifier: account.id)
+        noteTextView.setEmojis(account.emojis)
         
         // don't show relationship label for the user's own account
         if accountID != mastodonController.account?.id {
@@ -148,7 +148,7 @@ class ProfileHeaderView: UIView {
             valueTextView.isSelectable = false
             valueTextView.font = .systemFont(ofSize: 17)
             valueTextView.setTextFromHtml(field.value)
-            valueTextView.setEmojis(account.emojis, identifier: account.id)
+            valueTextView.setEmojis(account.emojis)
             valueTextView.textAlignment = .left
             valueTextView.awakeFromNib()
             valueTextView.navigationDelegate = delegate

Tusker/Views/StatusContentTextView.swift

@@ -16,8 +16,9 @@ class StatusContentTextView: ContentTextView {
     
     func setTextFrom(status: StatusMO) {
         statusID = status.id
+        emojiIdentifier = status.id
         setTextFromHtml(status.content)
-        setEmojis(status.emojis, identifier: status.id)
+        setEmojis(status.emojis)
     }
     
     override func getMention(for url: URL, text: String) -> Mention? {

Tusker/en.lproj/Localizable.stringsdict

@@ -5,7 +5,7 @@
 	<key>poll votes count</key>
 	<dict>
 		<key>NSStringLocalizedFormatKey</key>
-		<string>%#@votes@</string>
+		<string>%2$#@votes@</string>
 		<key>votes</key>
 		<dict>
 			<key>NSStringFormatSpecTypeKey</key>