RxCaptureMetadataOutputObjectsDelegateProxy.swift

import Foundation
import AVFoundation
import RxSwift
import RxCocoa

private let associatedkey = UnsafePointer<Void>(malloc(1))

class RxCaptureMetadataOutputObjectsDelegateProxy: DelegateProxy, DelegateProxyType, AVCaptureMetadataOutputObjectsDelegate {
  static func setCurrentDelegate(delegate: AnyObject?, toObject object: AnyObject) {
    (object as! AVCaptureMetadataOutput)
      .setMetadataObjectsDelegate(delegate.map { $0 as! AVCaptureMetadataOutputObjectsDelegate },
        queue: objc_getAssociatedObject(object, associatedkey) as! dispatch_queue_t)
  }

  static func currentDelegateFor(object: AnyObject) -> AnyObject? {
    return (object as! AVCaptureMetadataOutput).metadataObjectsDelegate
  }

  func observeDidOutputMetadataObjects() -> Observable<([AnyObject], AVCaptureConnection)> {
    return observe(#selector(AVCaptureMetadataOutputObjectsDelegate.captureOutput(_:didOutputMetadataObjects:fromConnection:)))
      .map { ($0[1] as! [AnyObject], $0[2] as! AVCaptureConnection) }
  }
}

extension AVCaptureMetadataOutput {
  func rx_metadataObjectsDelegate(queue: dispatch_queue_t) -> RxCaptureMetadataOutputObjectsDelegateProxy {
    objc_setAssociatedObject(self, associatedkey, queue, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
    return RxCaptureMetadataOutputObjectsDelegateProxy.proxyForObject(self)
  }
}