kplayer/kplayer/util/ImageLoadOperation.swift

//
// Created by Marco Schmickler on 21.03.15.
// Copyright (c) 2015 Marco Schmickler. All rights reserved.
//

import Foundation
import Alamofire
import Darwin

public class ImageLoadOperation: Operation {
    public typealias Succeeder = (UIImage) -> ()

    let imageURL: URL
    let succeeder: Succeeder
    let index: Int
    var request: DataRequest?

    var manager: Session?

    public init(imageURL: URL, succeeder: @escaping Succeeder, index: Int) {
        self.imageURL = imageURL
        self.succeeder = succeeder
        self.index = index
    }

    override public func main() {
        if imageURL.isFileURL {
            usleep(100000)
        }

        if self.isCancelled {
            return
        }

        print("lazy fetch image \(imageURL)")
        if let data = try? Data(contentsOf: imageURL) {
//            print("lazy fetch image ready \(imageURL)")
            if self.isCancelled {
                return
            }
            if let img = UIImage(data: data, scale: 1) {
                if imageURL.isFileURL {
                    DispatchQueue.main.async {
                        self.succeeder(img)
                    }
                    return
                }
                if let decodedImg = img.decodeImage() {
                    if self.isCancelled {
               //         print("Decoding 2 cancelled")
                        return
                    }
                    DispatchQueue.main.async {
                        print("lazy fetch image decoded")
                        self.succeeder(decodedImg)
                    }
                }
            }
        }
    }

    override public func cancel() {
//        if !self.isCancelled {
//            print("cancel load \(imageURL)")
//        }
        if let r = request {
            r.cancel()
        }

        super.cancel()
    }

}