Pills performance improvements (#1891)

* big performance improvement for pills

* small overall performance improvement

* code improvements

ElementX/Sources/Other/Pills/MessageText.swift

@@ -19,6 +19,7 @@ import SwiftUI
 final class MessageTextView: UITextView, PillAttachmentViewProviderDelegate {
     var roomContext: RoomScreenViewModel.Context?
     var updateClosure: (() -> Void)?
+    private var pillViews = NSHashTable<UIView>.weakObjects()
     
     // This prevents the magnifying glass from showing up
     override func gestureRecognizerShouldBegin(_ gestureRecognizer: UIGestureRecognizer) -> Bool {
@@ -39,20 +40,22 @@ final class MessageTextView: UITextView, PillAttachmentViewProviderDelegate {
         }
     }
 
-    // Required to setup the first rendering of the pill view
-    override func layoutSubviews() {
-        invalidateTextAttachmentsDisplay(update: false)
-        super.layoutSubviews()
+    func registerPillView(_ pillView: UIView) {
+        pillViews.add(pillView)
     }
 
-    func registerPillView(_ pillView: UIView) {
-        // No need to be implemented in this view
+    func flushPills() {
+        for view in pillViews.allObjects {
+            view.alpha = 0.0
+            view.removeFromSuperview()
+        }
+        pillViews.removeAllObjects()
     }
 }
 
 struct MessageText: UIViewRepresentable {
-    @Environment(\.openURL) private var openURLAction: OpenURLAction
-    @EnvironmentObject private var viewModel: RoomScreenViewModel.Context
+    @Environment(\.openURL) private var openURLAction
+    @Environment(\.roomContext) private var viewModel
     @State private var computedSizes = [Double: CGSize]()
     
     @State var attributedString: AttributedString {
@@ -92,7 +95,11 @@ struct MessageText: UIViewRepresentable {
     }
 
     func updateUIView(_ uiView: MessageTextView, context: Context) {
-        uiView.attributedText = NSAttributedString(attributedString)
+        let newAttributedText = NSAttributedString(attributedString)
+        if uiView.attributedText != newAttributedText {
+            uiView.flushPills()
+            uiView.attributedText = newAttributedText
+        }
         context.coordinator.openURLAction = openURLAction
     }
 
@@ -177,7 +184,6 @@ struct MessageText_Previews: PreviewProvider, TestablePreview {
         MessageText(attributedString: attributedString)
             .border(Color.purple)
             .previewDisplayName("Custom Text")
-            .environmentObject(RoomScreenViewModel.mock.context)
         // For comparison
         Text(attributedString)
             .border(Color.purple)
@@ -188,13 +194,11 @@ struct MessageText_Previews: PreviewProvider, TestablePreview {
             MessageText(attributedString: attributedString)
                 .border(Color.purple)
                 .previewDisplayName("With block quote")
-                .environmentObject(RoomScreenViewModel.mock.context)
         }
         if let attributedString = attributedStringBuilder.fromHTML(htmlStringWithList) {
             MessageText(attributedString: attributedString)
                 .border(Color.purple)
                 .previewDisplayName("With list")
-                .environmentObject(RoomScreenViewModel.mock.context)
         }
     }
 }

ElementX/Sources/Other/Pills/PillTextAttachment.swift

@@ -22,22 +22,17 @@ final class PillTextAttachment: NSTextAttachment {
         let encoder = JSONEncoder()
         guard let encodedData = try? encoder.encode(attachmentData) else { return nil }
         self.init(data: encodedData, ofType: InfoPlistReader.main.pillsUTType)
+        pillData = attachmentData
     }
     
-    var pillData: PillTextAttachmentData? {
-        guard let contents else {
-            return nil
-        }
-        let decoder = JSONDecoder()
-        return try? decoder.decode(PillTextAttachmentData.self, from: contents)
-    }
+    private(set) var pillData: PillTextAttachmentData!
     
     override func attachmentBounds(for textContainer: NSTextContainer?, proposedLineFragment lineFrag: CGRect, glyphPosition position: CGPoint, characterIndex charIndex: Int) -> CGRect {
         var rect = super.attachmentBounds(for: textContainer, proposedLineFragment: lineFrag, glyphPosition: position, characterIndex: charIndex)
-        if let font = pillData?.font {
+        
+        let fontData = pillData.fontData
         // Align the pill text vertically with the surrounding text.
-            rect.origin.y = font.descender + (font.lineHeight - rect.height) / 2.0
-        }
+        rect.origin.y = fontData.descender + (fontData.lineHeight - rect.height) / 2.0
         return rect
     }
 }

ElementX/Sources/Other/Pills/PillTextAttachmentData.swift

@@ -24,43 +24,22 @@ enum PillType: Codable, Equatable {
     case allUsers
 }
 
-struct PillTextAttachmentData {
-    // MARK: - Properties
+struct PillTextAttachmentData: Codable, Equatable {
+    struct Font: Codable, Equatable {
+        let descender: CGFloat
+        let lineHeight: CGFloat
+    }
     
     /// Pill type
     let type: PillType
     
     /// Font for the display name
-    let font: UIFont
+    let fontData: Font
 }
 
-extension PillTextAttachmentData: Codable {
-    // MARK: - Codable
-
-    enum CodingKeys: String, CodingKey {
-        case type
-        case font
-    }
-    
-    enum PillTextAttachmentDataError: Error {
-        case noFontData
-    }
-    
-    init(from decoder: Decoder) throws {
-        let container = try decoder.container(keyedBy: CodingKeys.self)
-        type = try container.decode(PillType.self, forKey: .type)
-        let fontData = try container.decode(Data.self, forKey: .font)
-        if let font = try NSKeyedUnarchiver.unarchivedObject(ofClass: UIFont.self, from: fontData) {
-            self.font = font
-        } else {
-            throw PillTextAttachmentDataError.noFontData
-        }
-    }
-
-    func encode(to encoder: Encoder) throws {
-        var container = encoder.container(keyedBy: CodingKeys.self)
-        try container.encode(type, forKey: .type)
-        let fontData = try NSKeyedArchiver.archivedData(withRootObject: font, requiringSecureCoding: false)
-        try container.encode(fontData, forKey: .font)
+extension PillTextAttachmentData {
+    init(type: PillType, font: UIFont) {
+        self.type = type
+        fontData = Font(descender: font.descender, lineHeight: font.lineHeight)
     }
 }

ElementX/Sources/Screens/RoomScreen/RoomScreenViewModel.swift

@@ -925,3 +925,16 @@ private struct ReplyInfo {
     let type: EventBasedMessageTimelineItemContentType
     let isThread: Bool
 }
+
+private struct RoomContextKey: EnvironmentKey {
+    @MainActor
+    static let defaultValue = RoomScreenViewModel.mock.context
+}
+
+extension EnvironmentValues {
+    /// Used to access and inject and access the room context without observing it
+    var roomContext: RoomScreenViewModel.Context {
+        get { self[RoomContextKey.self] }
+        set { self[RoomContextKey.self] = newValue }
+    }
+}

ElementX/Sources/Screens/RoomScreen/View/Timeline/TimelineTableViewController.swift

@@ -163,6 +163,7 @@ class TimelineTableViewController: UIViewController {
                     .id(id)
                     .frame(maxWidth: .infinity, alignment: .leading)
                     .environmentObject(coordinator.context) // Attempted fix at a crash in TimelineItemContextMenu
+                    .environment(\.roomContext, coordinator.context)
             }
             .margins(.all, self.timelineStyle.rowInsets)
             .minSize(height: 1)

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

@@ -16,7 +16,7 @@
 import SwiftUI
 
 struct RoomTimelineItemView: View {
-    @EnvironmentObject private var context: RoomScreenViewModel.Context
+    @Environment(\.roomContext) var context: RoomScreenViewModel.Context
     @ObservedObject var viewState: RoomTimelineItemViewState
     
     var body: some View {