Memory Leak Using IGListKit?

[Smiller193]

Through the help of everyone that contributes to this issues section I have been able to properly implement IGListKit for my comments section. I just want to start by saying thanks for that. Maybe this is an error and maybe this is not but I am using a viewController to display the cells that I use to render my comments. When I go to my viewController the memory spikes up which makes a little bit of sense. However when I leave the controller the memory never goes back down. When I go to a new controller the memory increases continously. Im trying to figure out if it is my implementation of IGListKit thats flawed or my overall logic in general because this seems like a memory leak to me. I will include my code below to see if anyone here could possibly help me.

This is my commentsController which implements the appropriate section controllers

import UIKit
import IGListKit
import Firebase

class NewCommentsViewController: UIViewController, UITextFieldDelegate,CommentsSectionDelegate,CommentInputAccessoryViewDelegate {
    //array of comments which will be loaded by a service function
    var comments = [CommentGrabbed]()
    var messagesRef: DatabaseReference?
    var bottomConstraint: NSLayoutConstraint?
    public let addHeader = "addHeader" as ListDiffable
    public var eventKey = ""
    //This creates a lazily-initialized variable for the IGListAdapter. The initializer requires three parameters:
    //1 updater is an object conforming to IGListUpdatingDelegate, which handles row and section updates. IGListAdapterUpdater is a default implementation that is suitable for your usage.
    //2 viewController is a UIViewController that houses the adapter. This view controller is later used for navigating to other view controllers.
    //3 workingRangeSize is the size of the working range, which allows you to prepare content for sections just outside of the visible frame.

    lazy var adapter: ListAdapter = {
        return ListAdapter(updater: ListAdapterUpdater(), viewController: self)
    }()

    // 1 IGListKit uses IGListCollectionView, which is a subclass of UICollectionView, which patches some functionality and prevents others.
    let collectionView: UICollectionView = {
        // 2 This starts with a zero-sized rect since the view isn’t created yet. It uses the UICollectionViewFlowLayout just as the ClassicFeedViewController did.
        let view = UICollectionView(frame: CGRect.zero, collectionViewLayout: UICollectionViewFlowLayout())
        // 3 The background color is set to white
        view.backgroundColor = UIColor.white
        return view
    }()

    //will fetch the comments from the database and append them to an array
    fileprivate func fetchComments(){
        comments.removeAll()
        messagesRef = Database.database().reference().child("Comments").child(eventKey)
       // print(eventKey)
        // print(comments.count)
        let query = messagesRef?.queryOrderedByKey()
        query?.observe(.value, with: { (snapshot) in
            guard let allObjects = snapshot.children.allObjects as? [DataSnapshot] else {
                return
            }
           // print(snapshot)

            allObjects.forEach({ (snapshot) in
                guard let commentDictionary = snapshot.value as? [String: Any] else{
                    return
                }
                guard let uid = commentDictionary["uid"] as? String else{
                    return
                }
                UserService.show(forUID: uid, completion: { (user) in
                    if let user = user {
                        let commentFetched = CommentGrabbed(user: user, dictionary: commentDictionary)
                        commentFetched.commentID = snapshot.key
                        let filteredArr = self.comments.filter { (comment) -> Bool in
                            return comment.commentID == commentFetched.commentID
                        }
                        if filteredArr.count == 0 {
                            self.comments.append(commentFetched)

                        }
                        self.adapter.performUpdates(animated: true)
                    }else{
                        print("user is null")

                    }
                    self.comments.sort(by: { (comment1, comment2) -> Bool in
                        return comment1.creationDate.compare(comment2.creationDate) == .orderedAscending
                    })
                    self.comments.forEach({ (comments) in
                    })
                })

            })

        }, withCancel: { (error) in
            print("Failed to observe comments")
        })

        //first lets fetch comments for current event
    }

    //allows you to gain access to the input accessory view that each view controller has for inputting text
    lazy var containerView: CommentInputAccessoryView = {
        let frame = CGRect(x: 0, y: 0, width: view.frame.width, height: 50)
        let commentInputAccessoryView = CommentInputAccessoryView(frame:frame)
        commentInputAccessoryView.delegate = self
        return commentInputAccessoryView
    }()

    @objc func handleSubmit(for comment: String?){
        guard let comment = comment, comment.count > 0 else{
            return
        }

        let userText = Comments(content: comment, uid: User.current.uid, profilePic: User.current.profilePic!,eventKey: eventKey)
        sendMessage(userText)
        // will clear the comment text field
        self.containerView.clearCommentTextField()
    }

    @objc func handleKeyboardNotification(notification: NSNotification){

        if let userinfo = notification.userInfo {

            if let keyboardFrame = (userinfo[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue{

                self.bottomConstraint?.constant = -(keyboardFrame.height)

                let isKeyboardShowing = notification.name == NSNotification.Name.UIKeyboardWillShow

                self.bottomConstraint?.constant = isKeyboardShowing ? -(keyboardFrame.height) : 0
                if isKeyboardShowing{
                    let contentInset = UIEdgeInsetsMake(0, 0, (keyboardFrame.height), 0)
                    collectionView.contentInset = UIEdgeInsetsMake(0, 0, (keyboardFrame.height), 0)
                    collectionView.scrollIndicatorInsets = contentInset
                }else {
                    let contentInset = UIEdgeInsetsMake(0, 0, 0, 0)
                    collectionView.contentInset = UIEdgeInsetsMake(0, 0, 0, 0)
                    collectionView.scrollIndicatorInsets = contentInset
                }

                UIView.animate(withDuration: 0, delay: 0, options: UIViewAnimationOptions.curveEaseOut, animations: {
                    self.view.layoutIfNeeded()
                }, completion: { (completion) in
                    if self.comments.count > 0  && isKeyboardShowing {
                        let item = self.collectionView.numberOfItems(inSection: self.collectionView.numberOfSections - 1)-1
                        let lastItemIndex = IndexPath(item: item, section: self.collectionView.numberOfSections - 1)
                        self.collectionView.scrollToItem(at: lastItemIndex, at: UICollectionViewScrollPosition.top, animated: true)

                    }
                })
            }
        }
    }

    override var inputAccessoryView: UIView? {
        get {
            return containerView
        }
    }

    override var canBecomeFirstResponder: Bool {
        return true
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        collectionView.frame = CGRect.init(x: 0, y: 0, width: UIScreen.main.bounds.width, height: UIScreen.main.bounds.height-40)
        view.addSubview(collectionView)
        collectionView.alwaysBounceVertical = true
        adapter.collectionView = collectionView
        adapter.dataSource = self
        NotificationCenter.default.addObserver(self, selector: #selector(handleKeyboardNotification), name: NSNotification.Name.UIKeyboardWillShow, object: nil)
        NotificationCenter.default.addObserver(self, selector: #selector(handleKeyboardNotification), name: NSNotification.Name.UIKeyboardWillHide, object: nil)
        collectionView.register(CommentCell.self, forCellWithReuseIdentifier: "CommentCell")
//        collectionView.register(CommentHeader.self, forCellWithReuseIdentifier: "HeaderCell")
        collectionView.keyboardDismissMode = .onDrag
        navigationItem.title = "Comments"
        self.navigationItem.hidesBackButton = true
        let backButton = UIBarButtonItem(image: UIImage(named: "icons8-Back-64"), style: .plain, target: self, action: #selector(GoBack))
        self.navigationItem.leftBarButtonItem = backButton
    }

    @objc func GoBack(){
        print("BACK TAPPED")
        self.dismiss(animated: true, completion: nil)
    }

    //look here
    func CommentSectionUpdared(sectionController: CommentsSectionController){
        print("like")
        self.fetchComments()
        self.adapter.performUpdates(animated: true)
    }
    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)

        fetchComments()
        tabBarController?.tabBar.isHidden = true
        //submitButton.isUserInteractionEnabled = true

    }
    //viewDidLayoutSubviews() is overridden, setting the collectionView frame to match the view bounds.
    override func viewDidLayoutSubviews() {
        super.viewDidLayoutSubviews()
        //    collectionView.frame = view.bounds
    }
    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }
}

extension NewCommentsViewController: ListAdapterDataSource {
    // 1 objects(for:) returns an array of data objects that should show up in the collection view. loader.entries is provided here as it contains the journal entries.
    func objects(for listAdapter: ListAdapter) -> [ListDiffable] {
        let items:[ListDiffable] = comments
        //print("comments = \(comments)")
        return items
    }

    // 2 For each data object, listAdapter(_:sectionControllerFor:) must return a new instance of a section controller. For now you’re returning a plain IGListSectionController to appease the compiler — in a moment, you’ll modify this to return a custom journal section controller.
    func listAdapter(_ listAdapter: ListAdapter, sectionControllerFor object: Any) -> ListSectionController {
        //the comment section controller will be placed here but we don't have it yet so this will be a placeholder
//        if let object = object as? ListDiffable, object === addHeader {
//            return CommentsHeaderSectionController()
//        }
        let sectionController = CommentsSectionController()
        sectionController.delegate = self

        return sectionController
    }

    // 3 emptyView(for:) returns a view that should be displayed when the list is empty. NASA is in a bit of a time crunch, so they didn’t budget for this feature.
    func emptyView(for listAdapter: ListAdapter) -> UIView? {
        let view = UIView()
        view.backgroundColor = UIColor.white
        return view
    }
}

extension NewCommentsViewController {
    func sendMessage(_ message: Comments) {
        ChatService.sendMessage(message, eventKey: eventKey)

    }
}

This is the controller that is tasked with presenting the commentsController on click of a button I have only inluded the functions that contribute to presenting the controller to save time and reading.

 let newCommentsController = NewCommentsViewController()
 lazy var navController = UINavigationController(rootViewController: newCommentsController)

  @objc func presentComments(){
        print("Comments button pressed")
        newCommentsController.eventKey = eventKey
        newCommentsController.comments.removeAll()
        newCommentsController.adapter.reloadData { (updated) in

        }

        present(navController, animated: true, completion: nil)

    }

Through opening the commentSection in various post i have seen memory go from 70 mb (When app opened) to 126 mb ( when comment section of a post is opened) 165 mb (when other comment section is closed and new comment section is opened)

[rnystrom]

Hey @Smiller193! Have you tried any debugging using Xcode's retain cycle detection?

[Smiller193]

Umm im not exactly sure how to do that tbh but I could look into it

[Smiller193]

@rnystrom

[rnystrom]

Yup that’s a good start! Take a look at that link and you can do some googling. Lots of resources on how to debug retain cycles that can at least help pinpoint what isn’t being released.

_{Sent with GitHawk}

[Smiller193]

Okay so I found three leaks but im not sure how I go about fixing them now.. I don't really get any useful out of them it seems @rnystrom

[rnystrom]

@Smiller193 what are the leaks?

[Smiller193]

@rnystrom according to the stack trace the leaks is in the commentSectionController and it may be coming from here

    override func sizeForItem(at index: Int) -> CGSize {
        let frame = CGRect(x: 0, y: 0, width: collectionContext!.containerSize.width, height: 50)
        let dummyCell = CommentCell(frame: frame)
        dummyCell.comment = comment
        dummyCell.layoutIfNeeded()
        let targetSize =  CGSize(width: collectionContext!.containerSize.width, height: 55)
        let estimatedSize = dummyCell.systemLayoutSizeFitting(targetSize)
        let height = max(40+8+8, estimatedSize.height)
        return  CGSize(width: collectionContext!.containerSize.width, height: height)

}

[Smiller193]

Is there any way to show what I see in the side menu like in a picture

[Smiller193]

[Smiller193]

@rnystrom these are the leaks and each time I click one of the mallocbytes it takes me to that function that I listed earlier

[Smiller193]

The leaks on my phone and the leaks on the simulator also seem to be different. On my phone the memory goes back down when I leave the screen on my simulator it just keeps increasing

[marcuswu0814]

@Smiller193 Maybe you could try to use [weak self] when you observe the change of Firebase in method fetchComments().

And you can also trying to log malloc stack, maybe can help you much easier to find memory issue.

_{Sent with GitHawk}

[Smiller193]

Okay I will try that

[lorixx]

Not applicable anymore