AsyncPhoto.swift

struct AsyncPhoto<ID, Content, Progress, Placeholder>: View where ID: Hashable, Content: View, Progress: View, Placeholder: View {
  // redacted
  
  init(id value: ID = "",
       scaledSize: CGSize,
       cache: AsyncPhotoCaching = AsyncPhotoCache.shared,
       data: @escaping (ID) async -> Data?,
       content: @escaping (Image) -> Content = { $0 },
       progress: @escaping () -> Progress = { ProgressView() },
       placeholder: @escaping () -> Placeholder = { Color(white: 0.839) }) {
    // redacted 
  }

  var body: some View {
    // redacted
  }

  @MainActor func load() async {
    // Here we access the cache
    if let image = cache.image(for: id, size: scaledSize) {
      phase = .success(Image(uiImage: image))
    }
    else {
      phase = .loading
      if let image = await prepareScaledImage(for: id) {
        guard !Task.isCancelled else { return }
        phase = .success(image)
      }
      else {
        guard !Task.isCancelled else { return }
        phase = .placeholder
      }
    }
  }

  private func prepareScaledImage(for id: ID) async -> Image? {
    guard let photoData = await data(id) else { return nil }
    guard let originalImage = UIImage(data: photoData) else { return nil }
    let scaledImage = await originalImage.scaled(toFill: scaledSize)
    guard let finalImage = await scaledImage.byPreparingForDisplay() else { return nil }
    // Here we store the scaled down image in the cache
    cache.store(finalImage, forID: id)
    return Image(uiImage: finalImage)
  }
}