Aspects in Swift

NCLibBase.swift

// https://github.com/steipete/Aspects
// usage
// NCLibBase.hook(object: UIViewController.self, selector: #selector(UIViewController.viewDidLoad), with: .after) { (aspect) in
//     if let instance = aspect.instance() as? UIViewController {
//         print("viewDidLoad")
//         print(instance.description)
//     }
// }

import Foundation
import Aspects

public struct NCLibBase {
    
    public enum AspectOption: UInt {
        case after = 0
        case instead = 1
        case before = 2
        case removal = 8
        var option: AspectOptions {
            return AspectOptions(rawValue: rawValue)
        }
    }
    
    @discardableResult
    public static func hook(object: NSObject.Type, selector: Selector, with: AspectOption, block: @escaping (AspectInfo) -> Void) -> AspectToken? {
        do {
            return try object.aspect_hook(selector, with: with.option, usingBlock: wrap(aspect: block))
        } catch {
            print(error)
            return nil
        }
    }
    
    @discardableResult
    public static func hook(object: NSObject, selector: Selector, with: AspectOption, block: @escaping (AspectInfo) -> Void) -> AspectToken? {
        do {
            return try object.aspect_hook(selector, with: with.option, usingBlock: wrap(aspect: block))
        } catch {
            print(error)
            return nil
        }
    }
    
    
    // util
    private static func wrap(aspect: ((AspectInfo) -> Void)?) -> AnyObject {
        let block:@convention(block) (AspectInfo)-> Void = { info in
            if let aspect = aspect {
                aspect(info)
            }
        }
        let object: AnyObject = unsafeBitCast(block, to: AnyObject.self)
        return object
    }
}