iOS应用程序崩溃com.apple.root.background-qos

Question

在应用程序中发现应用程序崩溃。我怀疑这可能是因为Firebase观察员的代码而发生的。因为在用户情况下，用户可以从一个事件转到一个用户配置文件（参与此事件），然后从用户配置文件可以返回到此事件我需要一个处理引用删除特定的观察者。正因为如此，我做了下面的代码。

的代码片段

fileprivate func firObserve(_ isObserve: Bool) { 
    guard card != nil else { return } 
    firCardObserverDBManager.observeParticipationCard(observer: self, card: card, isObserve: isObserve, success: { [weak self] (updatedCard) in 
      debugPrint("updated card") 
      self?.checkUpdatedCard(updatedCard) 
     }, removed: { [weak self] in 
      self?.isParticipationCardDateRemoved = true 
      self?.presentCardRemovedAlert() 
    }) { (error) in 
     DispatchQueue.main.async { 
      SVProgressHUD.showError(withStatus: error.localizedDescription) 
     } 
    } 
} 

从FIRCardObserverDBManager

fileprivate var observeParticipationCardObservers = NSMapTable<AnyObject, AnyObject>(keyOptions: .weakMemory, valueOptions: .strongMemory) 


func observeParticipationCard(observer: Any, card: CardModel, isObserve: Bool, success: ((_ updatedCard: CardModel) -> Void)?, removed: (() -> Void)?, fail: ((_ error: Error) -> Void)?) { 
    let ref = Database.database().reference().child(MainGateways.cards.rawValue).child(card.id) 

    if !isObserve { 
     guard let handle = self.observeParticipationCardObservers.object(forKey: observer as AnyObject) as? UInt else { return } 
     ref.removeObserver(withHandle: handle) 
     observeParticipationCardObservers.removeObject(forKey: observer as AnyObject) 
     return 
    } 

    if let observableVC = observer as? UIViewController { 
     observableVC.firReferences.append(ref) 
    } 

    DispatchQueue.global(qos: .background).async { 
     let handle = ref.observe(.value, with: { (snapshot) in 
      if snapshot.value is NSNull { 
       // not exist 
       removed?() 
      } 
      guard let json = snapshot.value as? [String : Any] else { return } 
      guard let updatedCard = Mapper<CardModel>().map(JSON: json) else { return } 
      success?(updatedCard) 
     }, withCancel: { (error) in 
      debugPrint(error.localizedDescription) 
      fail?(error) 
     }) 
     self.observeParticipationCardObservers.setObject(handle as AnyObject, forKey: observer as AnyObject) 
     debugPrint("observeParticipationCardObservers", self.observeParticipationCardObservers) 
    } 
} 

的UIViewController的扩展它

extension UIViewController { 

    private struct FirebaseQueues { 
     static var firQueues = [DatabaseQuery]() 
    } 

    var firQueues: [DatabaseQuery] { 
     get { 
      guard let firQueues = objc_getAssociatedObject(self, &FirebaseQueues.firQueues) as? [DatabaseQuery] else { return [] } 
      return firQueues 
     } 
     set { 
      objc_setAssociatedObject(self, &FirebaseQueues.firQueues, newValue, objc_AssociationPolicy.OBJC_ASSOCIATION_RETAIN_NONATOMIC) 
     } 
    } 

    private struct FirebaseReferences { 
     static var firReferences = [DatabaseReference]() 
    } 

    var firReferences: [DatabaseReference] { 
     get { 
      guard let firReferenses = objc_getAssociatedObject(self, &FirebaseReferences.firReferences) as? [DatabaseReference] else { return [] } 
      return firReferenses 
     } 
     set { 
      objc_setAssociatedObject(self, &FirebaseReferences.firReferences, newValue, objc_AssociationPolicy.OBJC_ASSOCIATION_RETAIN_NONATOMIC) 
     } 
    } 

    func removeFIRQueuesReferensesObservers() { 
     for firQueqry in firQueues { 
      firQueqry.removeAllObservers() 
     } 
     firQueues.removeAll() 
     for firRef in firReferences { 
      firRef.removeAllObservers() 
     } 
     firReferences.removeAll() 
    } 

} 

崩溃堆栈

Crashed: com.apple.root.background-qos 
    0 libswiftCore.dylib    0x1022ba574 swift_unknownRelease (__hidden#21375_:381) 
    1 myapp      0x1002e3fd0 specialized specialized _ArrayBufferProtocol._arrayOutOfPlaceUpdate<A where ...> (inout _ContiguousArrayBuffer<A.Element>, Int, Int, A1) ->() (EventsUpcomingVC.swift) 
    2 myapp      0x1002e0eb8 specialized Array._copyToNewBuffer(oldCount : Int) ->() (EventsUpcomingVC.swift) 
    3 myapp      0x100319a84 specialized ChatGeneralManager.(observeConversationModel(Bool, conversationID : String, updated :() ->()?, fail : (Error) ->()?) ->()).(closure #1).(closure #1) (ChatGeneralManager.swift) 
    4 myapp      0x100311f70 ChatGeneralManager.(observeConversationModel(Bool, conversationID : String, updated :() ->()?, fail : (Error) ->()?) ->()).(closure #1).(closure #1) (ChatGeneralManager.swift) 
    5 myapp      0x10032515c partial apply for ChatGeneralManager.(observeConversationModel(Bool, conversationID : String, updated :() ->()?, fail : (Error) ->()?) ->()).(closure #1).(closure #1) (ChatGeneralManager.swift) 
    6 libdispatch.dylib    0x185b9e9e0 _dispatch_call_block_and_release + 24 
    7 libdispatch.dylib    0x185b9e9a0 _dispatch_client_callout + 16 
    8 libdispatch.dylib    0x185baebac _dispatch_root_queue_drain + 888 
    9 libdispatch.dylib    0x185bae7d0 _dispatch_worker_thread3 + 124 
    10 libsystem_pthread.dylib  0x185da7100 _pthread_wqthread + 1096 
    11 libsystem_pthread.dylib  0x185da6cac start_wqthread + 4 

Answer 1

我认为数据应用程序崩溃是由于运行时中的函数不正确而发生的。改变功能后，我不再有应用程序崩溃。

private var queuesKey = 0 
private var referencesKey = 1 

extension UIViewController { 

    var firQueues: [DatabaseQuery]? { 
     get { 
      return objc_getAssociatedObject(self, &queuesKey) as? [DatabaseQuery] 
     } 
     set { 
      objc_setAssociatedObject(self, &queuesKey, newValue, objc_AssociationPolicy.OBJC_ASSOCIATION_RETAIN) 
     } 
    } 

    var firReferences: [DatabaseReference]? { 
     get { 
      return objc_getAssociatedObject(self, &referencesKey) as? [DatabaseReference] 
     } 
     set { 
      objc_setAssociatedObject(self, &referencesKey, newValue, objc_AssociationPolicy.OBJC_ASSOCIATION_RETAIN) 
     } 
    } 


    func removeFIRQueuesReferensesObservers() { 
     if var _firQueues = firQueues { 
      for firQueqry in _firQueues { 
       firQueqry.removeAllObservers() 
      } 
//   debugPrint("removeFIRQueuesReferensesObservers _firQueues start", _firQueues.count, "firQueues", firQueues?.count ?? "nil") 
      _firQueues.removeAll() 
      firQueues?.removeAll() 
//   debugPrint("removeFIRQueuesReferensesObservers _firQueues end", _firQueues.count, "firQueues", firQueues?.count ?? "nil") 
     } 

     if var _firReferences = firReferences { 
      for firRef in _firReferences { 
       firRef.removeAllObservers() 
      } 
//   debugPrint("removeFIRQueuesReferensesObservers _firReferences start", "_firReferences", _firReferences.count, "firReferences", firReferences?.count ?? "nil") 
      _firReferences.removeAll() 
      firReferences?.removeAll() 
//   debugPrint("removeFIRQueuesReferensesObservers _firReferences end", "_firReferences", _firReferences.count, "firReferences", firReferences?.count ?? "nil") 
     } 
    } 

}