当委托字段不称为`delegate`时实现`DelegateProxy`（RxSwift / RxCocoa）

Question

I need some help with DelegateProxy implementation. Specifically, what is the proper way of implementing it when the delegate field has different name than simply delegate ? Such as in SKPhysicsContactDelegate it is called contactDelegate . I tried defining a computed value delegate , but it did not do the trick - https://github.com/maxvol/RxSpriteKit/blob/master/Proxy/RxSKPhysicsContactDelegateProxy.swift

It fails with "DelegateProxy has no factory of <PKPhysicsWorld: 0x280b18990>. Implement DelegateProxy subclass for <PKPhysicsWorld: 0x280b18990> first." Perhaps it is not even related to the delegate field name, but this is the only difference with properly working proxies I could find.

UPDATE: Ha! I just noticed that error message says PKPhysicsWorld , not SKPhysicsWorld . So my hypothesis is that it has something to do with the fact that object in DelegateProxyFactory.createProxy is a PKPhysicsWorld instead of SKPhysicsWorld and _factories[ObjectIdentifier(mirror.subjectType)] returns nil .

Answer 1

The reason you are getting that error is because your registerKnownImplementations() function isn't getting run.

The following gist should work: https://gist.github.com/dtartaglia/9f1f937628504ca56dbb1aac7d91df2b

The code is also below but the gist can be kept up to date:

//
//  SKPhysicsWorld+Rx.swift
//
//  Created by Daniel Tartaglia on 21 Jan 2019.
//  Copyright © 2019 Daniel Tartaglia. MIT License.
//

import RxSwift
import SpriteKit

public
extension Reactive where Base: SKPhysicsWorld {

    var didBegin: Observable<SKPhysicsContact> {
        return Observable.create { observer in
            physicsContatctDelegatesLock.lock(); defer { physicsContatctDelegatesLock.unlock() }
            let uuid = UUID()
            if let (delegate, beginners, enders) = physicsContatctDelegates[self.base] {
                var new = beginners
                new[uuid] = observer
                physicsContatctDelegates[self.base] = (delegate, new, enders)
            }
            else {
                let delegate = PhysicsContactDelegate(for: self.base)
                self.base.contactDelegate = delegate
                physicsContatctDelegates[self.base] = (delegate, [uuid: observer], [:])
            }

            return Disposables.create {
                physicsContatctDelegatesLock.lock(); defer { physicsContatctDelegatesLock.unlock() }
                let (delegate, beginners, enders) = physicsContatctDelegates[self.base]!
                var new = beginners
                new.removeValue(forKey: uuid)
                if new.isEmpty && enders.isEmpty {
                    physicsContatctDelegates.removeValue(forKey: self.base)
                }
                else {
                    physicsContatctDelegates[self.base] = (delegate, new, enders)
                }
            }
        }
    }

    var didEnd: Observable<SKPhysicsContact> {
        return Observable.create { observer in
            physicsContatctDelegatesLock.lock(); defer { physicsContatctDelegatesLock.unlock() }
            let uuid = UUID()
            if let (delegate, beginners, enders) = physicsContatctDelegates[self.base] {
                var new = enders
                new[uuid] = observer
                physicsContatctDelegates[self.base] = (delegate, beginners, new)
            }
            else {
                let delegate = PhysicsContactDelegate(for: self.base)
                self.base.contactDelegate = delegate
                physicsContatctDelegates[self.base] = (delegate, [:], [uuid: observer])
            }

            return Disposables.create {
                physicsContatctDelegatesLock.lock(); defer { physicsContatctDelegatesLock.unlock() }
                let (delegate, beginners, enders) = physicsContatctDelegates[self.base]!
                var new = enders
                new.removeValue(forKey: uuid)
                if new.isEmpty && enders.isEmpty {
                    physicsContatctDelegates.removeValue(forKey: self.base)
                }
                else {
                    physicsContatctDelegates[self.base] = (delegate, beginners, new)
                }
            }
        }
    }
}

private
class PhysicsContactDelegate: NSObject, SKPhysicsContactDelegate {

    init(for world: SKPhysicsWorld) {
        self.world = world
        super.init()
    }

    func didBegin(_ contact: SKPhysicsContact) {
        physicsContatctDelegatesLock.lock(); defer { physicsContatctDelegatesLock.unlock() }
        let (_, beginners, _) = physicsContatctDelegates[world]!
        for each in beginners.values {
            each.onNext(contact)
        }
    }

    func didEnd(_ contact: SKPhysicsContact) {
        physicsContatctDelegatesLock.lock(); defer { physicsContatctDelegatesLock.unlock() }
        let (_, _, enders) = physicsContatctDelegates[world]!
        for each in enders.values {
            each.onNext(contact)
        }
    }

    let world: SKPhysicsWorld
}

private let physicsContatctDelegatesLock = NSRecursiveLock()
private var physicsContatctDelegates: [SKPhysicsWorld: (SKPhysicsContactDelegate, [UUID: AnyObserver<SKPhysicsContact>], [UUID: AnyObserver<SKPhysicsContact>])] = [:]