vector-im/element-x-ios/issues/134 - Prevent home screen room last me…

ElementX/Sources/Other/HTMLParsing/AttributedStringBuilder.swift

@@ -32,6 +32,12 @@ struct AttributedStringBuilder: AttributedStringBuilderProtocol {
         }
     }
 
+    func fromPlain(_ string: String?) async -> AttributedString? {
+        await Task.detached {
+            fromPlain(string)
+        }.value
+    }
+
     func fromPlain(_ string: String?) -> AttributedString? {
         guard let string = string else {
             return nil
@@ -44,6 +50,12 @@ struct AttributedStringBuilder: AttributedStringBuilderProtocol {
         return try? AttributedString(mutableAttributedString, including: \.elementX)
     }
 
+    func fromHTML(_ htmlString: String?) async -> AttributedString? {
+        await Task.detached {
+            fromHTML(htmlString)
+        }.value
+    }
+
     // Do not use the default HTML renderer of NSAttributedString because this method
     // runs on the UI thread which we want to avoid because renderHTMLString is called
     // most of the time from a background thread.

ElementX/Sources/Other/HTMLParsing/AttributedStringBuilderProtocol.swift

@@ -15,7 +15,10 @@ struct AttributedStringBuilderComponent: Hashable {
 
 protocol AttributedStringBuilderProtocol {
     func fromPlain(_ string: String?) -> AttributedString?
+    func fromPlain(_ string: String?) async -> AttributedString?
+
     func fromHTML(_ htmlString: String?) -> AttributedString?
+    func fromHTML(_ htmlString: String?) async -> AttributedString?
 
     func blockquoteCoalescedComponentsFrom(_ attributedString: AttributedString?) -> [AttributedStringBuilderComponent]?
 }

ElementX/Sources/Screens/HomeScreen/HomeScreenModels.swift

@@ -70,7 +70,7 @@ struct HomeScreenRoom: Identifiable, Equatable {
 
     var displayName: String?
 
-    let topic: String?
+    var topic: String?
     var lastMessage: String?
 
     var avatar: UIImage?

ElementX/Sources/Screens/HomeScreen/HomeScreenViewModel.swift

@@ -23,6 +23,11 @@ class HomeScreenViewModel: HomeScreenViewModelType, HomeScreenViewModelProtocol
     private let attributedStringBuilder: AttributedStringBuilderProtocol
 
     private var roomUpdateListeners = Set<AnyCancellable>()
+    private var roomsUpdateTask: Task<Void, Never>? {
+        willSet {
+            roomsUpdateTask?.cancel()
+        }
+    }
 
     private var roomSummaries: [RoomSummaryProtocol]? {
         didSet {
@@ -56,14 +61,29 @@ class HomeScreenViewModel: HomeScreenViewModelType, HomeScreenViewModelProtocol
     }
 
     func updateWithRoomSummaries(_ roomSummaries: [RoomSummaryProtocol]) {
-        self.roomSummaries = roomSummaries
+        roomsUpdateTask = Task {
+            await updateWithRoomSummaries(roomSummaries)
+        }
+    }
+
+    private func updateWithRoomSummaries(_ roomSummaries: [RoomSummaryProtocol]) async {
+        var rooms = [HomeScreenRoom]()
+        for summary in roomSummaries {
+            if Task.isCancelled {
+                return
+            }
+
+            rooms.append(await buildOrUpdateRoomForSummary(summary))
+        }
 
-        state.rooms = roomSummaries.map { roomSummary in
-            buildOrUpdateRoomFromSummary(roomSummary)
+        if Task.isCancelled {
+            return
         }
 
-        roomUpdateListeners.removeAll()
+        state.rooms = rooms
+        self.roomSummaries = roomSummaries
 
+        roomUpdateListeners.removeAll()
         roomSummaries.forEach { roomSummary in
             roomSummary.callbacks
                 .receive(on: DispatchQueue.main)
@@ -72,10 +92,16 @@ class HomeScreenViewModel: HomeScreenViewModelType, HomeScreenViewModelProtocol
                         return
                     }
 
-                    switch callback {
-                    case .updatedData:
+                    Task {
                         if let index = self.state.rooms.firstIndex(where: { $0.id == roomSummary.id }) {
-                            self.state.rooms[index] = self.buildOrUpdateRoomFromSummary(roomSummary)
+                            switch callback {
+                            case .updatedLastMessage:
+                                var room = self.state.rooms[index]
+                                room.lastMessage = await self.lastMessageFromEventBrief(roomSummary.lastMessage)
+                                self.state.rooms[index] = room
+                            default:
+                                self.state.rooms[index] = await self.buildOrUpdateRoomForSummary(roomSummary)
+                            }
                         }
                     }
                 }
@@ -110,14 +136,12 @@ class HomeScreenViewModel: HomeScreenViewModelType, HomeScreenViewModelProtocol
         Task { await roomSummary.loadDetails() }
     }
 
-    private func buildOrUpdateRoomFromSummary(_ roomSummary: RoomSummaryProtocol) -> HomeScreenRoom {
-        let lastMessage = lastMessageFromEventBrief(roomSummary.lastMessage)
-
+    private func buildOrUpdateRoomForSummary(_ roomSummary: RoomSummaryProtocol) async -> HomeScreenRoom {
         guard var room = state.rooms.first(where: { $0.id == roomSummary.id }) else {
             return HomeScreenRoom(id: roomSummary.id,
                                   displayName: roomSummary.displayName,
                                   topic: roomSummary.topic,
-                                  lastMessage: lastMessage,
+                                  lastMessage: await lastMessageFromEventBrief(roomSummary.lastMessage),
                                   avatar: roomSummary.avatar,
                                   isDirect: roomSummary.isDirect,
                                   isEncrypted: roomSummary.isEncrypted,
@@ -127,20 +151,20 @@ class HomeScreenViewModel: HomeScreenViewModelType, HomeScreenViewModelProtocol
 
         room.avatar = roomSummary.avatar
         room.displayName = roomSummary.displayName
-        room.lastMessage = lastMessage
-
+        room.topic = roomSummary.topic
+                
         return room
     }
 
-    private func lastMessageFromEventBrief(_ eventBrief: EventBrief?) -> String? {
+    private func lastMessageFromEventBrief(_ eventBrief: EventBrief?) async -> String? {
         guard let eventBrief = eventBrief else {
             return nil
         }
 
         let senderDisplayName = senderDisplayNameForBrief(eventBrief)
 
         if let htmlBody = eventBrief.htmlBody,
-           let lastMessageAttributedString = attributedStringBuilder.fromHTML(htmlBody) {
+           let lastMessageAttributedString = await attributedStringBuilder.fromHTML(htmlBody) {
             return "\(senderDisplayName): \(String(lastMessageAttributedString.characters))"
         } else {
             return "\(senderDisplayName): \(eventBrief.body)"

ElementX/Sources/Services/Room/RoomProxy.swift

@@ -57,9 +57,7 @@ class RoomProxy: RoomProxyProtocol {
         room.setDelegate(delegate: nil)
     }
 
-    var id: String {
-        room.id()
-    }
+    lazy var id: String = room.id()
 
     var name: String? {
         room.name()

ElementX/Sources/Services/Room/RoomSummary/RoomSummary.swift

@@ -46,21 +46,21 @@ class RoomSummary: RoomSummaryProtocol {
         roomProxy.isTombstoned
     }
 
-    private(set) var displayName: String? {
+    private(set) var avatar: UIImage? {
         didSet {
-            callbacks.send(.updatedData)
+            callbacks.send(.updatedAvatar)
         }
     }
 
-    private(set) var lastMessage: EventBrief? {
+    private(set) var displayName: String? {
         didSet {
-            callbacks.send(.updatedData)
+            callbacks.send(.updatedDisplayName)
         }
     }
 
-    private(set) var avatar: UIImage? {
+    private(set) var lastMessage: EventBrief? {
         didSet {
-            callbacks.send(.updatedData)
+            callbacks.send(.updatedLastMessage)
         }
     }
 

ElementX/Sources/Services/Room/RoomSummary/RoomSummaryProtocol.swift

@@ -10,7 +10,9 @@ import Combine
 import UIKit
 
 enum RoomSummaryCallback {
-    case updatedData
+    case updatedAvatar
+    case updatedDisplayName
+    case updatedLastMessage
 }
 
 @MainActor

ElementX/Sources/Services/Timeline/RoomTimelineController.swift

@@ -18,6 +18,11 @@ class RoomTimelineController: RoomTimelineControllerProtocol {
     private let memberDetailProvider: MemberDetailProviderProtocol
 
     private var cancellables = Set<AnyCancellable>()
+    private var timelineItemsUpdateTask: Task<Void, Never>? {
+        willSet {
+            timelineItemsUpdateTask?.cancel()
+        }
+    }
 
     let callbacks = PassthroughSubject<RoomTimelineControllerCallback, Never>()
 
@@ -96,10 +101,20 @@ class RoomTimelineController: RoomTimelineControllerProtocol {
     }
 
     private func updateTimelineItems() {
+        timelineItemsUpdateTask = Task {
+            await asyncUpdateTimelineItems()
+        }
+    }
+
+    private func asyncUpdateTimelineItems() async {
         var newTimelineItems = [RoomTimelineItemProtocol]()
 
         var previousMessage: RoomMessageProtocol?
         for message in timelineProvider.messages {
+            if Task.isCancelled {
+                return
+            }
+
             let areMessagesFromTheSameDay = haveSameDay(lhs: previousMessage, rhs: message)
             let shouldAddSectionHeader = !areMessagesFromTheSameDay
 
@@ -111,13 +126,17 @@ class RoomTimelineController: RoomTimelineControllerProtocol {
             let areMessagesFromTheSameSender = (previousMessage?.sender == message.sender)
             let shouldShowSenderDetails = !areMessagesFromTheSameSender || !areMessagesFromTheSameDay
 
-            newTimelineItems.append(timelineItemFactory.buildTimelineItemFor(message: message,
-                                                                             isOutgoing: message.sender == userId,
-                                                                             showSenderDetails: shouldShowSenderDetails))
+            newTimelineItems.append(await timelineItemFactory.buildTimelineItemFor(message: message,
+                                                                                   isOutgoing: message.sender == userId,
+                                                                                   showSenderDetails: shouldShowSenderDetails))
 
             previousMessage = message
         }
 
+        if Task.isCancelled {
+            return
+        }
+
         timelineItems = newTimelineItems
 
         callbacks.send(.updatedTimelineItems)

ElementX/Sources/Services/Timeline/TimelineItems/RoomTimelineItemFactory.swift

@@ -22,20 +22,20 @@ struct RoomTimelineItemFactory: RoomTimelineItemFactoryProtocol {
         self.attributedStringBuilder = attributedStringBuilder
     }
 
-    func buildTimelineItemFor(message: RoomMessageProtocol, isOutgoing: Bool, showSenderDetails: Bool) -> RoomTimelineItemProtocol {
+    func buildTimelineItemFor(message: RoomMessageProtocol, isOutgoing: Bool, showSenderDetails: Bool) async -> RoomTimelineItemProtocol {
         let displayName = memberDetailProvider.displayNameForUserId(message.sender)
         let avatarURL = memberDetailProvider.avatarURLStringForUserId(message.sender)
         let avatarImage = mediaProvider.imageFromURLString(avatarURL)
 
         switch message {
         case let message as TextRoomMessage:
-            return buildTextTimelineItemFromMessage(message, isOutgoing, showSenderDetails, displayName, avatarImage)
+            return await buildTextTimelineItemFromMessage(message, isOutgoing, showSenderDetails, displayName, avatarImage)
         case let message as ImageRoomMessage:
-            return buildImageTimelineItemFromMessage(message, isOutgoing, showSenderDetails, displayName, avatarImage)
+            return await buildImageTimelineItemFromMessage(message, isOutgoing, showSenderDetails, displayName, avatarImage)
         case let message as NoticeRoomMessage:
-            return buildNoticeTimelineItemFromMessage(message, isOutgoing, showSenderDetails, displayName, avatarImage)
+            return await buildNoticeTimelineItemFromMessage(message, isOutgoing, showSenderDetails, displayName, avatarImage)
         case let message as EmoteRoomMessage:
-            return buildEmoteTimelineItemFromMessage(message, isOutgoing, showSenderDetails, displayName, avatarImage)
+            return await buildEmoteTimelineItemFromMessage(message, isOutgoing, showSenderDetails, displayName, avatarImage)
         default:
             fatalError("Unknown room message.")
         }
@@ -47,8 +47,8 @@ struct RoomTimelineItemFactory: RoomTimelineItemFactoryProtocol {
                                                   _ isOutgoing: Bool,
                                                   _ showSenderDetails: Bool,
                                                   _ displayName: String?,
-                                                  _ avatarImage: UIImage?) -> RoomTimelineItemProtocol {
-        let attributedText = (message.htmlBody != nil ? attributedStringBuilder.fromHTML(message.htmlBody) : attributedStringBuilder.fromPlain(message.body))
+                                                  _ avatarImage: UIImage?) async -> RoomTimelineItemProtocol {
+        let attributedText = await (message.htmlBody != nil ? attributedStringBuilder.fromHTML(message.htmlBody) : attributedStringBuilder.fromPlain(message.body))
         let attributedComponents = attributedStringBuilder.blockquoteCoalescedComponentsFrom(attributedText)
 
         return TextRoomTimelineItem(id: message.id,
@@ -66,7 +66,7 @@ struct RoomTimelineItemFactory: RoomTimelineItemFactoryProtocol {
                                                    _ isOutgoing: Bool,
                                                    _ showSenderDetails: Bool,
                                                    _ displayName: String?,
-                                                   _ avatarImage: UIImage?) -> RoomTimelineItemProtocol {
+                                                   _ avatarImage: UIImage?) async -> RoomTimelineItemProtocol {
         var aspectRatio: CGFloat?
         if let width = message.width,
            let height = message.height {
@@ -93,8 +93,8 @@ struct RoomTimelineItemFactory: RoomTimelineItemFactoryProtocol {
                                                     _ isOutgoing: Bool,
                                                     _ showSenderDetails: Bool,
                                                     _ displayName: String?,
-                                                    _ avatarImage: UIImage?) -> RoomTimelineItemProtocol {
-        let attributedText = (message.htmlBody != nil ? attributedStringBuilder.fromHTML(message.htmlBody) : attributedStringBuilder.fromPlain(message.body))
+                                                    _ avatarImage: UIImage?) async -> RoomTimelineItemProtocol {
+        let attributedText = await (message.htmlBody != nil ? attributedStringBuilder.fromHTML(message.htmlBody) : attributedStringBuilder.fromPlain(message.body))
         let attributedComponents = attributedStringBuilder.blockquoteCoalescedComponentsFrom(attributedText)
 
         return NoticeRoomTimelineItem(id: message.id,
@@ -112,8 +112,8 @@ struct RoomTimelineItemFactory: RoomTimelineItemFactoryProtocol {
                                                    _ isOutgoing: Bool,
                                                    _ showSenderDetails: Bool,
                                                    _ displayName: String?,
-                                                   _ avatarImage: UIImage?) -> RoomTimelineItemProtocol {
-        let attributedText = (message.htmlBody != nil ? attributedStringBuilder.fromHTML(message.htmlBody) : attributedStringBuilder.fromPlain(message.body))
+                                                   _ avatarImage: UIImage?) async -> RoomTimelineItemProtocol {
+        let attributedText = await (message.htmlBody != nil ? attributedStringBuilder.fromHTML(message.htmlBody) : attributedStringBuilder.fromPlain(message.body))
         let attributedComponents = attributedStringBuilder.blockquoteCoalescedComponentsFrom(attributedText)
 
         return EmoteRoomTimelineItem(id: message.id,

ElementX/Sources/Services/Timeline/TimelineItems/RoomTimelineItemFactoryProtocol.swift

@@ -10,5 +10,5 @@ import Foundation
 
 @MainActor
 protocol RoomTimelineItemFactoryProtocol {
-    func buildTimelineItemFor(message: RoomMessageProtocol, isOutgoing: Bool, showSenderDetails: Bool) -> RoomTimelineItemProtocol
+    func buildTimelineItemFor(message: RoomMessageProtocol, isOutgoing: Bool, showSenderDetails: Bool) async -> RoomTimelineItemProtocol
 }