Various optimisations (#1878)

* Cache TimelineBubbleLayout subview sizes

* Cache MessageText sizes, avoid extra updates

* Only use the `CollapsibleReactionLayout` if there's more than 5 reactions on a particular message

* Upgrade Sentry to 8.13.0, disable various options as they're not useful and impact performance

* Address PR comments, fix unit tests

ElementX/Sources/Screens/RoomScreen/View/Style/TimelineBubbleLayout.swift

@@ -21,6 +21,10 @@ import SwiftUI
 /// A custom layout is required as the embedded quote bubbles should fill the entire width of
 /// the message bubble, without causing the width of the bubble to fill all of the available space.
 struct TimelineBubbleLayout: Layout {
+    struct Cache {
+        var sizes = [Int: [ProposedViewSize: CGSize]]()
+    }
+    
     /// The spacing between the components in the bubble.
     let spacing: CGFloat
     
@@ -36,13 +40,23 @@ struct TimelineBubbleLayout: Layout {
         static let regularText: Double = 1
     }
     
-    func sizeThatFits(proposal: ProposedViewSize, subviews: Subviews, cache: inout ()) -> CGSize {
+    func makeCache(subviews: Subviews) -> Cache {
+        Cache()
+    }
+    
+    func updateCache(_ cache: inout Cache, subviews: Subviews) {
+        // A subview changed, reset everything
+        cache = Cache()
+    }
+    
+    func sizeThatFits(proposal: ProposedViewSize, subviews: Subviews, cache: inout Cache) -> CGSize {
         guard !subviews.isEmpty else { return .zero }
         
         // Calculate the natural size using the regular text and non-greedy quote bubbles.
         let layoutSubviews = subviews.filter { $0.priority != Priority.visibleQuote }
+
+        let subviewSizes = layoutSubviews.map { size(for: $0, subviews: subviews, proposedSize: proposal, cache: &cache) }
         
-        let subviewSizes = layoutSubviews.map { $0.sizeThatFits(proposal) }
         let maxWidth = subviewSizes.map(\.width).reduce(0, max)
         let totalHeight = subviewSizes.map(\.height).reduce(0, +)
         let totalSpacing = CGFloat(layoutSubviews.count - 1) * spacing
@@ -50,16 +64,17 @@ struct TimelineBubbleLayout: Layout {
         return CGSize(width: maxWidth, height: totalHeight + totalSpacing)
     }
     
-    func placeSubviews(in bounds: CGRect, proposal: ProposedViewSize, subviews: Subviews, cache: inout ()) {
+    func placeSubviews(in bounds: CGRect, proposal: ProposedViewSize, subviews: Subviews, cache: inout Cache) {
         guard !subviews.isEmpty else { return }
         
         // Calculate the width using the regular text and the non-greedy quote bubbles.
         let layoutSubviews = subviews.filter { $0.priority != Priority.visibleQuote }
-        let maxWidth = layoutSubviews.map { $0.sizeThatFits(proposal).width }.reduce(0, max)
+        let maxWidth = layoutSubviews.map { size(for: $0, subviews: subviews, proposedSize: proposal, cache: &cache).width }.reduce(0, max)
         
         // Place the regular text and greedy quote bubbles using the calculated width.
         let visibleSubviews = subviews.filter { $0.priority != Priority.hiddenQuote }
-        let subviewSizes = visibleSubviews.map { $0.sizeThatFits(ProposedViewSize(width: maxWidth, height: proposal.height)) }
+
+        let subviewSizes = visibleSubviews.map { size(for: $0, subviews: subviews, proposedSize: ProposedViewSize(width: maxWidth, height: proposal.height), cache: &cache) }
         
         var y = bounds.minY
         for index in visibleSubviews.indices {
@@ -70,4 +85,25 @@ struct TimelineBubbleLayout: Layout {
             y += height + spacing
         }
     }
+    
+    // MARK: - Private
+    
+    private func size(for subview: LayoutSubview, subviews: LayoutSubviews, proposedSize: ProposedViewSize, cache: inout Cache) -> CGSize {
+        guard let index = subviews.firstIndex(of: subview) else {
+            fatalError()
+        }
+        
+        if cache.sizes[index] == nil {
+            cache.sizes[index] = [:]
+        }
+        
+        if let cachedSize = cache.sizes[index]?[proposedSize] {
+            return cachedSize
+        }
+        
+        let size = subview.sizeThatFits(proposedSize)
+        
+        cache.sizes[index]?[proposedSize] = size
+        return size
+    }
 }