Upload OperationQueue.swift

Multi-threading_Practice/OperationQueue.swift

+//
+//  OperationQueue.swift
+//  FOSS_PR
+//
+//  Created by 김사랑 on 2024/06/23.
+//
+
+import UIKit
+
+let catAPIURL = "https://api.thecatapi.com/v1/images/search?limit=3"
+
+extension ViewController {
+
+    func loadImagesUsingOperationQueue() {
+        guard let url = URL(string: catAPIURL) else { return }
+
+        let operationQueue = OperationQueue()
+        let downloadOperation = BlockOperation {
+            do {
+                let data = try Data(contentsOf: url)
+                if let jsonArray = try JSONSerialization.jsonObject(with: data, options: []) as? [[String: Any]] {
+                    var downloadedImages: [UIImage] = []
+
+                    let downloadQueue = OperationQueue()
+
+                    for json in jsonArray {
+                        if let imageUrlString = json["url"] as? String,
+                           let imageUrl = URL(string: imageUrlString) {
+                            let imageDownloadOperation = BlockOperation {
+                                if let imageData = try? Data(contentsOf: imageUrl),
+                                   let image = UIImage(data: imageData) {
+                                    downloadedImages.append(image)
+                                }
+                            }
+                            downloadQueue.addOperation(imageDownloadOperation)
+                        }
+                    }
+                    downloadQueue.waitUntilAllOperationsAreFinished()
+
+                    OperationQueue.main.addOperation {
+                        self.originalImages = downloadedImages
+                        self.images = downloadedImages
+                        self.collectionView.reloadData()
+                    }
+                }
+            } catch {
+                OperationQueue.main.addOperation {
+                    let alert = UIAlertController(title: "Error", message: "Failed to load images.", preferredStyle: .alert)
+                    alert.addAction(UIAlertAction(title: "OK", style: .default))
+                    self.present(alert, animated: true)
+                }
+            }
+        }
+        operationQueue.addOperation(downloadOperation)
+    }
+
+    func applyFilterUsingOperationQueue() {
+        let operationQueue = OperationQueue()
+
+        let filterOperation = BlockOperation {
+            var filteredImages: [UIImage] = []
+            for image in self.originalImages {
+                let filteredImage = self.applyFilter(to: image)
+                filteredImages.append(filteredImage)
+            }
+            OperationQueue.main.addOperation {
+                self.images = filteredImages
+                self.collectionView.reloadData()
+            }
+        }
+
+        operationQueue.addOperation(filterOperation)
+    }
+
+    func resetImagesUsingOperationQueue() {
+        OperationQueue.main.addOperation {
+            self.images = self.originalImages
+            self.collectionView.reloadData()
+        }
+    }
+
+    func applyFilter(to image: UIImage) -> UIImage {
+        let context = CIContext()
+        let filter = CIFilter(name: "CIPhotoEffectNoir")
+        filter?.setValue(CIImage(image: image), forKey: kCIInputImageKey)
+        if let outputImage = filter?.outputImage,
+           let cgImage = context.createCGImage(outputImage, from: outputImage.extent) {
+            return UIImage(cgImage: cgImage)
+        }
+        return image
+    }
+}