Merge pull request #2217 from anyproto/ios-3181-show-attachments-in-m…

…essage-list

iOS-3181 Video preview storage | migrate to actor (to chat)

Anytype/Sources/ServiceLayer/VideoPreviewStorage/VideoPreviewStorage.swift

@@ -7,17 +7,16 @@ protocol VideoPreviewStorageProtocol {
     func preview(url: URL, size: CGSize) async throws -> UIImage
 }
 
-final class VideoPreviewStorage: VideoPreviewStorageProtocol {
+actor VideoPreviewStorage: VideoPreviewStorageProtocol {
 
     private struct StorageKey: Hashable {
         let url: URL
         let size: CGSize
     }
 
+    private var taskCache = [StorageKey: Task<UIImage, any Error>]()
     private let storage: Storage<StorageKey, UIImage>?
 
-    private let operationsQueue = DispatchQueue(label: "VideoPreviewQueue")
-
     init() {
         let diskConfig = DiskConfig(name: "VideoPreviewCache", maxSize: 30 * 1024 * 1024) // 30 Mb
         let memoryConfig = MemoryConfig(expiry: .never, countLimit: 100, totalCostLimit: 300)
@@ -31,58 +30,42 @@ final class VideoPreviewStorage: VideoPreviewStorageProtocol {
     }
 
     func preview(url: URL, size: CGSize) async throws -> UIImage {
-        return try await withCheckedThrowingContinuation { continuation in
-            loadPreviewInQueue(url: url, size: size) { result in
-                switch result {
-                case .success(let success):
-                    continuation.resume(returning: success)
-                case .failure(let failure):
-                    continuation.resume(throwing: failure)
-                }
-            }
-        }
-    }
-
-    private func loadPreviewInQueue(url: URL, size: CGSize, completion: @escaping (Result<UIImage, any Error>) -> Void) {
 
         let key = StorageKey(url: url, size: size)
 
-        operationsQueue.async { [weak self] in
-
-            guard let self else {
-                completion(.failure(CommonError.undefined))
-                return
-            }
-
-            if let image = try? storage?.object(forKey: key) {
-                completion(.success(image))
-                return
-            }
-
-            guard let image = UIImage(videoPreview: url, size: size) else {
-                completion(.failure(CommonError.undefined))
-                return
-            }
-
+        if let task = taskCache[key] {
+            return try await task.value
+        }
+
+        if let image = try? storage?.object(forKey: key) {
+            return image
+        }
+
+        let task = Task {
+            return try UIImage(videoPreview: url, size: size)
+        }
+
+        taskCache[key] = task
+
+        do {
+            let image = try await task.value
             try? storage?.setObject(image, forKey: key)
-            completion(.success(image))
+            return image
+        } catch {
+            taskCache[key] = nil
+            throw error
         }
     }
 }
 
 fileprivate extension UIImage {
 
-    convenience init?(videoPreview path: URL?, size: CGSize) {
-        guard let path else { return nil }
-        do {
-            let asset = AVURLAsset(url: path, options: nil)
-            let imgGenerator = AVAssetImageGenerator(asset: asset)
-            imgGenerator.appliesPreferredTrackTransform = true
-            imgGenerator.maximumSize = size
-            let cgImage = try imgGenerator.copyCGImage(at: CMTimeMake(value: 0, timescale: 1), actualTime: nil)
-            self.init(cgImage: cgImage)
-        } catch {
-            return nil
-        }
+    convenience init(videoPreview path: URL, size: CGSize) throws {
+        let asset = AVURLAsset(url: path, options: nil)
+        let imgGenerator = AVAssetImageGenerator(asset: asset)
+        imgGenerator.appliesPreferredTrackTransform = true
+        imgGenerator.maximumSize = size
+        let cgImage = try imgGenerator.copyCGImage(at: CMTimeMake(value: 0, timescale: 1), actualTime: nil)
+        self.init(cgImage: cgImage)
     }
 }