Extract data from processor .data and pass to .image

[missphyrgames]

Hello, I'm trying to extract some data from a processor in the .data case and pass it along to the .image case. For example, I have following code:

struct  CustomProcessor: ImageProcessor {
   
    let identifier: String

    func process(item: ImageProcessItem, options: KingfisherParsedOptionsInfo) -> KFCrossPlatformImage? {
        switch item {
        case .image(let image):
            // want to use metadata here
            // do something
            return image
        case .data:
            // I want to extract some metadata from the image here
           let src = CGImageSourceCreateWithData(data as CFData, nil)

           // how can I use this in the .image case when we pass back the data to the DefaultImageProcessor?
           let metadata = CGImageSourceCopyMetadataAtIndex(src!, 0, nil)

            return (DefaultImageProcessor.default |> self).process(item: item, options: options)
        }
    }
}

Any help would be appreciated!

[onevcat]

I am not sure if it is an abusing of ImageProcessor, but how about these code?

struct MetaDataProcessor: ImageProcessor {
    let metaData: MetaData // can be an int, or anything else you can customize.
    var identifier: String {  /* It is better to return a value can be identified by the metaData.  */  }

    func process(item: ImageProcessItem, options: KingfisherParsedOptionsInfo) -> KFCrossPlatformImage? {
        switch item {
        case .image(let image):
            // You now have the correct metaData here.
            return image
        case .data:
            // You can even leave empty, this case won't be called.
            return UIImage()
        }
    }
}

struct CustomProcessor: ImageProcessor {
   
    let identifier: String

    func process(item: ImageProcessItem, options: KingfisherParsedOptionsInfo) -> KFCrossPlatformImage? {
        switch item {
        case .image(let image):
            return image
        case .data:
           let src = CGImageSourceCreateWithData(data as CFData, nil)
           let metadata = CGImageSourceCopyMetadataAtIndex(src!, 0, nil)
           let next = MetaDataProcessor(metaData: metadata)
           return (DefaultImageProcessor.default |> next).process(item: item, options: options)
        }
    }
}

And in the use case, make sure you set the CustomProcessor as the first of the .processor option.

[missphyrgames]

Thank you so much @onevcat!