perf(editor): apply native edit source to line index

Sources/SaplingEditor/DocumentLineIndex.swift

@@ -156,10 +156,16 @@ public struct DocumentLineIndex: Hashable, Sendable {
     public mutating func replace(_ edit: DocumentLineIndexEdit) -> DocumentLineIndexEditResult {
         let oldSource = source as NSString
         let oldLength = oldSource.length
-        let range = NSRange(
+        let range = clampedRange(edit.range, sourceLength: oldLength)
-            location: max(0, min(edit.range.location, oldLength)),
+        let updatedSource = oldSource.replacingCharacters(in: range, with: edit.replacement)
-            length: max(0, min(edit.range.length, oldLength - max(0, min(edit.range.location, oldLength))))
+        return replace(edit, updatedSource: updatedSource)
-        )
+    }
+
+    @discardableResult
+    public mutating func replace(_ edit: DocumentLineIndexEdit, updatedSource: String) -> DocumentLineIndexEditResult {
+        let oldSource = source as NSString
+        let oldLength = oldSource.length
+        let range = clampedRange(edit.range, sourceLength: oldLength)
         let replacement = edit.replacement
         let replacementLength = (replacement as NSString).length
         let locationDelta = replacementLength - range.length
@@ -172,7 +178,7 @@ public struct DocumentLineIndex: Hashable, Sendable {
         let scanStart = boundaries[lowerLineIndex].contentRange.location
         let oldScanEnd = boundaries[upperLineIndex].nextLineLocation
 
-        source = oldSource.replacingCharacters(in: range, with: replacement)
+        source = updatedSource
 
         let newSource = source as NSString
         let newScanEnd = max(scanStart, min(newSource.length, oldScanEnd + locationDelta))
@@ -202,6 +208,14 @@ public struct DocumentLineIndex: Hashable, Sendable {
         )
     }
 
+    private func clampedRange(_ range: NSRange, sourceLength: Int) -> NSRange {
+        let location = max(0, min(range.location, sourceLength))
+        return NSRange(
+            location: location,
+            length: max(0, min(range.length, sourceLength - location))
+        )
+    }
+
     private func editorLine(for boundary: DocumentLineBoundary, activeLineIndex: Int) -> EditorLine {
         let nsSource = source as NSString
         return EditorLine(

Sources/SaplingEditor/EditorArchitecture.swift

@@ -124,8 +124,12 @@ public struct EditorState: Hashable, Sendable {
         activeLineIndex = lineIndex.lineIndex(containing: selection.location)
     }
 
-    public mutating func updateSource(_ edit: DocumentLineIndexEdit, selection newSelection: EditorSelection? = nil) {
+    public mutating func updateSource(
-        lineIndex.replace(edit)
+        _ source: String,
+        edit: DocumentLineIndexEdit,
+        selection newSelection: EditorSelection? = nil
+    ) {
+        lineIndex.replace(edit, updatedSource: source)
         document.source = lineIndex.source
         selection = EditorActiveLineTracker.clampedSelection(newSelection ?? selection, in: document.source)
         activeLineIndex = lineIndex.lineIndex(containing: selection.location)

Sources/SaplingEditor/EditorPerformanceProfiling.swift

@@ -178,7 +178,7 @@ public enum EditorBenchmarkProfiler {
         )
         let changedSource = sourceByInsertingProbeText(in: source, at: midpoint)
         var changedLineIndex = lineIndex
-        changedLineIndex.replace(typingEdit)
+        changedLineIndex.replace(typingEdit, updatedSource: changedSource)
         let changedActiveLineIndex = changedLineIndex.lineIndex(containing: midpoint + 1)
 
         let activeLineResult = measure {
@@ -221,7 +221,8 @@ public enum EditorBenchmarkProfiler {
         let sourceUpdateResult = measure {
             var updatedState = state
             updatedState.updateSource(
-                typingEdit,
+                changedSource,
+                edit: typingEdit,
                 selection: EditorSelection(location: midpoint + typingEdit.replacementUTF16Length, length: 0)
             )
         }

Sources/SaplingEditor/HybridMarkdownEditor.swift

@@ -54,7 +54,7 @@ public final class HybridMarkdownEditorViewModel: ObservableObject, EditorCoordi
         guard state.document.source != source else { return }
         let previousActiveLineIndex = state.activeLineIndex
         if let edit {
-            state.updateSource(edit, selection: selection)
+            state.updateSource(source, edit: edit, selection: selection)
         } else {
             state.updateSource(source)
             if let selection {
@@ -286,7 +286,7 @@ private struct NativeMarkdownTextView: NSViewRepresentable {
             let selection = EditorSelection(range: textView.selectedRange())
             let edit = pendingEdit
             if let edit {
-                currentLineIndex.replace(edit)
+                currentLineIndex.replace(edit, updatedSource: textView.string)
             } else {
                 currentLineIndex = DocumentLineIndex(source: textView.string)
             }
@@ -515,7 +515,7 @@ private struct NativeMarkdownTextView: UIViewRepresentable {
             let selection = EditorSelection(range: textView.selectedRange)
             let edit = pendingEdit
             if let edit {
-                currentLineIndex.replace(edit)
+                currentLineIndex.replace(edit, updatedSource: textView.text)
             } else {
                 currentLineIndex = DocumentLineIndex(source: textView.text)
             }

Sources/SaplingEditorBenchmark/main.swift

@@ -7,6 +7,15 @@ struct BenchmarkScenario {
     var url: URL
 }
 
+let trackedInteractionMetricNames = [
+    "active_line_lookup",
+    "selection_update",
+    "dirty_line_invalidation_click",
+    "typing_state_update",
+    "dirty_line_invalidation_typing",
+    "render_update_typing_dirty"
+]
+
 let arguments = Array(CommandLine.arguments.dropFirst())
 let repositoryRoot = URL(fileURLWithPath: FileManager.default.currentDirectoryPath, isDirectory: true)
 
@@ -99,15 +108,6 @@ func printScenario(name: String, result: EditorBenchmarkResult) {
     print("")
 }
 
-let trackedInteractionMetricNames = [
-    "active_line_lookup",
-    "selection_update",
-    "dirty_line_invalidation_click",
-    "typing_state_update",
-    "dirty_line_invalidation_typing",
-    "render_update_typing_dirty"
-]
-
 func format(_ value: Double) -> String {
     String(format: "%.3f", value)
 }