Concurrency Fixes (#283)

* Review places where MainActor used

* Adapt to MainActor changes, avoid redundant task detachments

* Move Rust client operations into a dedicated concurrent queue, make init async

* Add changelog

* Fixed small working for awaiting non-async method

* Remove some redundant tasks

* Put back some main actors

* Fix tests

* Fixed timeline updates when the number of items doesn't change. Keeps more previous home screen room data between reloads

Co-authored-by: Stefan Ceriu <stefanc@matrix.org>

ElementX/Sources/Services/Media/MediaProvider.swift

@@ -55,43 +55,38 @@ struct MediaProvider: MediaProviderProtocol {
             return .success(image)
         }
 
-        let loadImageBgTask = backgroundTaskService.startBackgroundTask(withName: "LoadImage: \(source.underlyingSource.url().hashValue)")
+        let loadImageBgTask = await backgroundTaskService.startBackgroundTask(withName: "LoadImage: \(source.url.hashValue)")
         defer {
             loadImageBgTask?.stop()
         }
         
-        let cacheKey = cacheKeyForURLString(source.underlyingSource.url(), avatarSize: avatarSize)
-        
-        return await Task.detached { () -> Result<UIImage, MediaProviderError> in
-            if case let .success(cacheResult) = await imageCache.retrieveImage(forKey: cacheKey),
-               let image = cacheResult.image {
-                return .success(image)
-            }
-            
-            do {
-                let imageData = try await Task.detached { () -> Data in
-                    if let avatarSize {
-                        return try await clientProxy.loadMediaThumbnailForSource(source.underlyingSource, width: UInt(avatarSize.scaledValue), height: UInt(avatarSize.scaledValue))
-                    } else {
-                        return try await clientProxy.loadMediaContentForSource(source.underlyingSource)
-                    }
-                    
-                }.value
-                
-                guard let image = UIImage(data: imageData) else {
-                    MXLog.error("Invalid image data")
-                    return .failure(.invalidImageData)
-                }
-                
-                imageCache.store(image, forKey: cacheKey)
-                
-                return .success(image)
-            } catch {
-                MXLog.error("Failed retrieving image with error: \(error)")
-                return .failure(.failedRetrievingImage)
-            }
+        let cacheKey = cacheKeyForURLString(source.url, avatarSize: avatarSize)
+
+        if case let .success(cacheResult) = await imageCache.retrieveImage(forKey: cacheKey),
+           let image = cacheResult.image {
+            return .success(image)
+        }
+
+        do {
+            let imageData: Data
+            if let avatarSize {
+                imageData = try await clientProxy.loadMediaThumbnailForSource(source.underlyingSource, width: UInt(avatarSize.scaledValue), height: UInt(avatarSize.scaledValue))
+            } else {
+                imageData = try await clientProxy.loadMediaContentForSource(source.underlyingSource)
+            }
+
+            guard let image = UIImage(data: imageData) else {
+                MXLog.error("Invalid image data")
+                return .failure(.invalidImageData)
+            }
+
+            imageCache.store(image, forKey: cacheKey)
+
+            return .success(image)
+        } catch {
+            MXLog.error("Failed retrieving image with error: \(error)")
+            return .failure(.failedRetrievingImage)
         }
-        .value
     }
     
     // MARK: - Private

ElementX/Sources/Services/Media/MediaProviderProtocol.swift

@@ -22,7 +22,6 @@ enum MediaProviderError: Error {
     case invalidImageData
 }
 
-@MainActor
 protocol MediaProviderProtocol {
     func imageFromSource(_ source: MediaSource?, avatarSize: AvatarSize?) -> UIImage?
     

ElementX/Sources/Services/Media/MediaSource.swift

@@ -19,6 +19,10 @@ import MatrixRustSDK
 
 struct MediaSource: Equatable {
     let underlyingSource: MatrixRustSDK.MediaSource
+
+    var url: String {
+        underlyingSource.url()
+    }
     
     init(source: MatrixRustSDK.MediaSource) {
         underlyingSource = source