speedup opening of attach menu (#1900)

* speedup opening of attach menu

the check, if there were any webxdc apps ever is comparable expensive
on larger databases and if there are webxdc apps.
in this case, check only once (otherwise the checke is not that expensive).

* move loading to thread and do not mix virtual list with addItem()

DcCore/DcCore/DC/Wrapper.swift

@@ -105,6 +105,7 @@ public class DcContext {
     var contextPointer: OpaquePointer?
     public var lastWarningString: String = "" // temporary thing to get a grip on some weird errors
     public var maxConfigureProgress: Int = 0 // temporary thing to get a grip on some weird errors
+    private var anyWebxdcSeen: Bool = false
 
     public init(contextPointer: OpaquePointer?, logger: Logger?) {
         self.contextPointer = contextPointer
@@ -273,7 +274,10 @@ public class DcContext {
     }
 
     public func hasWebxdc(chatId: Int) -> Bool {
-        return !getChatMedia(chatId: chatId, messageType: DC_MSG_WEBXDC, messageType2: 0, messageType3: 0).isEmpty
+        if !anyWebxdcSeen {
+            anyWebxdcSeen = !getChatMedia(chatId: chatId, messageType: DC_MSG_WEBXDC, messageType2: 0, messageType3: 0).isEmpty
+        }
+        return anyWebxdcSeen
     }
 
     public func getAllMediaCount(chatId: Int) -> String {

deltachat-ios/Chat/ChatViewController.swift

@@ -1524,8 +1524,7 @@ class ChatViewController: UITableViewController, UITableViewDropDelegate {
     }
 
     private func showWebxdcSelector() {
-        let msgIds = dcContext.getChatMedia(chatId: 0, messageType: DC_MSG_WEBXDC, messageType2: 0, messageType3: 0)
-        let webxdcSelector = WebxdcSelector(context: dcContext, mediaMessageIds: msgIds.reversed())
+        let webxdcSelector = WebxdcSelector(context: dcContext)
         webxdcSelector.delegate = self
         let webxdcSelectorNavigationController = UINavigationController(rootViewController: webxdcSelector)
         if #available(iOS 15.0, *) {

deltachat-ios/Controller/WebxdcSelector.swift

@@ -11,9 +11,7 @@ class WebxdcSelector: UIViewController {
 
     private let dcContext: DcContext
     // MARK: - data
-    private var mediaMessageIds: [Int]
-    private var deduplicatedMessageHashes: [String: Int]
-    private var deduplicatedMessageIds: [Int]
+    private var deduplicatedMessageIds: [Int] = []
     private var items: [Int: GalleryItem] = [:]
 
     // MARK: - subview specs
@@ -70,13 +68,9 @@ class WebxdcSelector: UIViewController {
         return mediaPicker
     }()
 
-    init(context: DcContext, mediaMessageIds: [Int]) {
+    init(context: DcContext) {
         self.dcContext = context
-        self.mediaMessageIds = mediaMessageIds
-        self.deduplicatedMessageHashes = [:]
-        self.deduplicatedMessageIds = []
         super.init(nibName: nil, bundle: nil)
-        deduplicateWebxdcs()
     }
 
     required init?(coder: NSCoder) {
@@ -90,13 +84,7 @@ class WebxdcSelector: UIViewController {
         title = String.localized("webxdc_apps")
         navigationItem.setLeftBarButton(filesButton, animated: false)
         navigationItem.setRightBarButton(cancelButton, animated: false)
-        if mediaMessageIds.isEmpty {
-            emptyStateView.isHidden = false
-        }
-    }
-
-    override func viewWillAppear(_ animated: Bool) {
-        grid.reloadData()
+        deduplicateWebxdcs()
     }
 
     override func viewWillLayoutSubviews() {
@@ -112,21 +100,21 @@ class WebxdcSelector: UIViewController {
         grid.topAnchor.constraint(equalTo: view.topAnchor).isActive = true
         grid.trailingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.trailingAnchor, constant: 0).isActive = true
         grid.bottomAnchor.constraint(equalTo: view.bottomAnchor).isActive = true
-
         emptyStateView.addCenteredTo(parentView: view)
     }
 
     func deduplicateWebxdcs() {
+        var deduplicatedMessageHashes: [String: Int] = [:]
         DispatchQueue.global(qos: .userInteractive).async { [weak self] in
             guard let self = self else { return }
-            for id in self.mediaMessageIds {
+            let mediaMessageIds = dcContext.getChatMedia(chatId: 0, messageType: DC_MSG_WEBXDC, messageType2: 0, messageType3: 0).reversed()
+            for id in mediaMessageIds {
                 guard let filename = self.dcContext.getMessage(id: id).fileURL else { continue }
                 if let hash = try? NSData(contentsOf: filename).sha1() {
                     DispatchQueue.main.async {
-                        if self.deduplicatedMessageHashes[hash] == nil {
-                            self.deduplicatedMessageHashes[hash] = id
+                        if deduplicatedMessageHashes[hash] == nil {
+                            deduplicatedMessageHashes[hash] = id
                             self.deduplicatedMessageIds.append(id)
-                            self.grid.insertItems(at: [IndexPath(row: self.deduplicatedMessageIds.count - 1, section: 0)])
                         }
                     }
                 }
@@ -136,6 +124,7 @@ class WebxdcSelector: UIViewController {
                 if self.deduplicatedMessageIds.isEmpty {
                     self.emptyStateView.isHidden = false
                 }
+                self.grid.reloadData()
             }
         }
     }