iOS應用程序崩潰com.apple.root.background-qos

Question

在應用程序中發現應用程序崩潰。我懷疑這可能是因爲Firebase觀察員的代碼而發生的。因爲在用戶情況下，用戶可以從一個事件轉到一個用戶配置文件（參與此事件），然後從用戶配置文件可以返回到此事件我需要一個處理引用刪除特定的觀察者。正因爲如此，我做了下面的代碼。

的代碼片段

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) 
     } 
    } 
} 

從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的擴展它

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() 
    } 

} 

崩潰堆棧

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

我認爲數據應用程序崩潰是由於運行時中的函數不正確而發生的。改變功能後，我不再有應用程序崩潰。

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") 
     } 
    } 

}