Improve performance of presenting ChatChannelVC (#3448)

CHANGELOG.md

@@ -13,6 +13,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 ### 🐞 Fixed
 - Unread messages divider did not appear in the message list when marking messages as unread [#3444](https://github.com/GetStream/stream-chat-swift/pull/3444)
 - Fix UI glitch in thread parent message when sending a message and scrolling [#3446](https://github.com/GetStream/stream-chat-swift/pull/3446)
+### ⚡ Performance
+- Improve performance of presenting `ChatChannelVC` [#3448](https://github.com/GetStream/stream-chat-swift/pull/3448)
 
 # [4.64.0](https://github.com/GetStream/stream-chat-swift/releases/tag/4.64.0)
 _October 02, 2024_

Scripts/updateDependency.sh

@@ -73,6 +73,7 @@ fi
 
 if [[ $dependency_directory == *"SwiftyMarkdown"* ]]; then
     # We currently use customized version of SwiftyMarkdown
+	git restore $output_directory/SwiftyMarkdown/PerformanceLog.swift || true
     git restore $output_directory/SwiftyMarkdown/SwiftyLineProcessor.swift || true
     git restore $output_directory/SwiftyMarkdown/SwiftyTokeniser.swift || true
 fi

Sources/StreamChatUI/ChatMessageList/ChatMessage/ChatMessageContentView.swift

@@ -157,6 +157,10 @@ open class ChatMessageContentView: _View, ThemeProvider, UITextViewDelegate {
     open var editedLabelSeparator: String {
         " • "
     }
+
+    /// Skip content update when tintColorDidChange is called but content was already updated for that color
+    /// Unnecessary updates can get expensive due to text updates.
+    private var previousContentUpdateTintColor: UIColor?
 
     // MARK: - Content views
 
@@ -590,6 +594,7 @@ open class ChatMessageContentView: _View, ThemeProvider, UITextViewDelegate {
         super.updateContent()
         defer {
             attachmentViewInjector?.contentViewDidUpdateContent()
+            previousContentUpdateTintColor = tintColor
             setNeedsLayout()
         }
 
@@ -747,7 +752,7 @@ open class ChatMessageContentView: _View, ThemeProvider, UITextViewDelegate {
 
     override open func tintColorDidChange() {
         super.tintColorDidChange()
-
+        guard previousContentUpdateTintColor != tintColor else { return }
         guard UIApplication.shared.applicationState == .active else { return }
         // We need to update the content and manually apply the updated `tintColor`
         // to the subviews which don't listen for `tintColor` updates.

Sources/StreamChatUI/ChatMessageList/ChatMessageListVC.swift

@@ -271,7 +271,6 @@ open class ChatMessageListVC: _ViewController,
 
     override open func traitCollectionDidChange(_ previousTraitCollection: UITraitCollection?) {
         super.traitCollectionDidChange(previousTraitCollection)
-
         view.layoutIfNeeded()
         listView.adjustContentInsetToPositionMessagesAtTheTop()
     }
@@ -1304,10 +1303,14 @@ private extension ChatMessageListVC {
             }
 
             UIView.performWithoutAnimation {
-                self?.scrollToBottomIfNeeded(with: changes, newestChange: newestChange)
-                self?.reloadMovedMessage(newestChange: newestChange)
-                self?.reloadPreviousMessagesForVisibleRemoves(with: changes)
-                self?.reloadPreviousMessageWhenInsertingNewMessage()
+                guard let self else { return }
+                self.scrollToBottomIfNeeded(with: changes, newestChange: newestChange)
+                var additionalChanges = Set<IndexPath>()
+                additionalChanges.formUnion(self.reloadMovedMessage(newestChange: newestChange))
+                additionalChanges.formUnion(self.reloadPreviousMessagesForVisibleRemoves(with: changes))
+                additionalChanges.formUnion(self.reloadPreviousMessageWhenInsertingNewMessage(with: changes))
+                guard !additionalChanges.isEmpty else { return }
+                self.listView.reloadRows(at: additionalChanges.sorted(), with: .none)
             }
 
             self?.scrollPendingMessageIfNeeded()
@@ -1356,24 +1359,21 @@ private extension ChatMessageListVC {
 
     // If we are inserting messages at the bottom, update the previous cell
     // to hide the timestamp of the previous message if needed.
-    func reloadPreviousMessageWhenInsertingNewMessage() {
-        guard isFirstPageLoaded else { return }
-        if listView.isLastCellFullyVisible && listView.newMessagesSnapshot.count > 1 {
-            let previousMessageIndexPath = IndexPath(item: 1, section: 0)
-            listView.reloadRows(at: [previousMessageIndexPath], with: .none)
-        }
+    private func reloadPreviousMessageWhenInsertingNewMessage(with changes: [ListChange<ChatMessage>]) -> [IndexPath] {
+        guard isFirstPageLoaded else { return [] }
+        guard listView.isLastCellFullyVisible && listView.newMessagesSnapshot.count > 1 else { return [] }
+        guard !changes.contains(where: { $0.indexPath.item == 1 && $0.isInsertion }) else { return [] }
+        return [IndexPath(item: 1, section: 0)]
     }
 
     // When there are deletions, we should update the previous message, so that we add the
     // avatar image is rendered back and the timestamp too. Since we have an inverted list, the previous
     // message has the same index of the deleted message after the deletion has been executed.
-    func reloadPreviousMessagesForVisibleRemoves(with changes: [ListChange<ChatMessage>]) {
+    private func reloadPreviousMessagesForVisibleRemoves(with changes: [ListChange<ChatMessage>]) -> [IndexPath] {
         let visibleRemoves = changes.filter {
             $0.isRemove && isMessageVisible(at: $0.indexPath)
         }
-        visibleRemoves.forEach {
-            listView.reloadRows(at: [$0.indexPath], with: .none)
-        }
+        return visibleRemoves.map(\.indexPath)
     }
 
     // Scroll to the bottom if the new message was sent by
@@ -1391,10 +1391,7 @@ private extension ChatMessageListVC {
 
     // When a Giphy moves to the bottom, we need to also trigger a reload
     // Since a move doesn't trigger a reload of the cell.
-    func reloadMovedMessage(newestChange: ListChange<ChatMessage>?) {
-        if newestChange?.isMove == true {
-            let movedIndexPath = IndexPath(item: 0, section: 0)
-            listView.reloadRows(at: [movedIndexPath], with: .none)
-        }
+    private func reloadMovedMessage(newestChange: ListChange<ChatMessage>?) -> [IndexPath] {
+        newestChange?.isMove == true ? [IndexPath(item: 0, section: 0)] : []
     }
 }

Sources/StreamChatUI/StreamSwiftyMarkdown/SwiftyMarkdown/PerfomanceLog.swift

@@ -16,7 +16,7 @@ class PerformanceLog {
 
 	init( with environmentVariableName : String, identifier : String, log : OSLog  ) {
 		self.log = log
-		self.enablePerfomanceLog = (ProcessInfo.processInfo.environment[environmentVariableName] != nil)
+		self.enablePerfomanceLog = false
 		self.identifier = identifier
 	}
 

Tests/StreamChatUITests/SnapshotTests/ChatChannel/ChatChannelVC_Tests.swift

@@ -652,6 +652,10 @@ final class ChatChannelVC_Tests: XCTestCase {
 
         vc.components.isMessageEditedLabelEnabled = true
 
+        // Also update the default because in snapshot tests, message cells are created before they are in the responder chain
+        defer { Components.default.isMessageEditedLabelEnabled = false }
+        Components.default.isMessageEditedLabelEnabled = true
+
         AssertSnapshot(vc, variants: [.defaultLight])
     }
 

Tests/StreamChatUITests/SnapshotTests/ChatMessageList/ChatMessageListVC_Tests.swift

@@ -506,7 +506,7 @@ final class ChatMessageListVC_Tests: XCTestCase {
         ])
         mockedListView.updateMessagesCompletion?()
 
-        XCTAssertEqual(mockedListView.reloadRowsCallCount, 2)
+        XCTAssertEqual(mockedListView.reloadRowsCallCount, 1)
         XCTAssertEqual(mockedListView.reloadRowsCalledWith, [.init(item: 0, section: 0), .init(item: 1, section: 0)])
     }