CodeEditApp · thecoolwinter · Apr 9, 2025 · Apr 8, 2025 · Apr 9, 2025 · Apr 9, 2025
diff --git a/Sources/CodeEditTextView/TextLayoutManager/TextLayoutManager+Edits.swift b/Sources/CodeEditTextView/TextLayoutManager/TextLayoutManager+Edits.swift
@@ -10,17 +10,50 @@ import AppKit
 // MARK: - Edits
 
 extension TextLayoutManager: NSTextStorageDelegate {
-    /// Notifies the layout manager of an edit.
+    /// Receives edit notifications from the text storage and updates internal data structures to stay in sync with
+    /// text content.
     ///
-    /// Used by the `TextView` to tell the layout manager about any edits that will happen.
-    /// Use this to keep the layout manager's line storage in sync with the text storage.
+    /// If the changes are only attribute changes, this method invalidates layout for the edited range and returns.
     ///
-    /// - Parameters:
-    ///   - range: The range of the edit.
-    ///   - string: The string to replace in the given range.
-    public func willReplaceCharactersInRange(range: NSRange, with string: String) {
+    /// Otherwise, any lines that were removed or replaced by the edit are first removed from the text line layout
+    /// storage. Then, any new lines are inserted into the same storage.
+    ///
+    /// For instance, if inserting a newline this method will:
+    /// - Remove no lines (none were replaced)
+    /// - Update the current line's range to contain the newline character.
+    /// - Insert a new line after the current line.
+    ///
+    /// If a selection containing a newline is deleted and replaced with two more newlines this method will:
+    /// - Delete the original line.
+    /// - Insert two lines.
+    ///
+    /// - Note: This method *does not* cause a layout calculation. If a method is finding `NaN` values for line
+    ///         fragments, ensure `layout` or `ensureLayoutUntil` are called on the subject ranges.
+    public func textStorage(
+        _ textStorage: NSTextStorage,
+        didProcessEditing editedMask: NSTextStorageEditActions,
+        range editedRange: NSRange,
+        changeInLength delta: Int
+    ) {
+        guard editedMask.contains(.editedCharacters) else {
+            if editedMask.contains(.editedAttributes) && delta == 0 {
+                invalidateLayoutForRange(editedRange)
+            }
+            return
+        }
+
+        let insertedStringRange = NSRange(location: editedRange.location, length: editedRange.length - delta)
+        removeLayoutLinesIn(range: insertedStringRange)
+        insertNewLines(for: editedRange)
+        invalidateLayoutForRange(editedRange)
+    }
+
+    /// Removes all lines in the range, as if they were deleted. This is a setup for inserting the lines back in on an
+    /// edit.
+    /// - Parameter range: The range that was deleted.
+    private func removeLayoutLinesIn(range: NSRange) {
         // Loop through each line being replaced in reverse, updating and removing where necessary.
-         for linePosition in lineStorage.linesInRange(range).reversed() {
+        for linePosition in lineStorage.linesInRange(range).reversed() {
             // Two cases: Updated line, deleted line entirely
             guard let intersection = linePosition.range.intersection(range), !intersection.isEmpty else { continue }
             if intersection == linePosition.range && linePosition.range.max != lineStorage.length {
@@ -38,25 +71,24 @@ extension TextLayoutManager: NSTextStorageDelegate {
                 lineStorage.update(atIndex: linePosition.range.location, delta: -intersection.length, deltaHeight: 0)
             }
         }
+    }
 
+    /// Inserts any newly inserted lines into the line layout storage. Exits early if the range is empty.
+    /// - Parameter range: The range of the string that was inserted into the text storage.
+    private func insertNewLines(for range: NSRange) {
+        guard !range.isEmpty, let string = textStorage?.substring(from: range) as? NSString else { return }
         // Loop through each line being inserted, inserting & splitting where necessary
-        if !string.isEmpty {
-            var index = 0
-            while let nextLine = (string as NSString).getNextLine(startingAt: index) {
-                let lineRange = NSRange(start: index, end: nextLine.max)
-                applyLineInsert((string as NSString).substring(with: lineRange) as NSString, at: range.location + index)
-                index = nextLine.max
-            }
+        var index = 0
+        while let nextLine = string.getNextLine(startingAt: index) {
+            let lineRange = NSRange(start: index, end: nextLine.max)
+            applyLineInsert(string.substring(with: lineRange) as NSString, at: range.location + index)
+            index = nextLine.max
+        }
 
-            if index < (string as NSString).length {
-                // Get the last line.
-                applyLineInsert(
-                    (string as NSString).substring(from: index) as NSString,
-                    at: range.location + index
-                )
-            }
+        if index < string.length {
+            // Get the last line.
+            applyLineInsert(string.substring(from: index) as NSString, at: range.location + index)
         }
-        setNeedsLayout()
     }
 
     /// Applies a line insert to the internal line storage tree.
@@ -65,7 +97,7 @@ extension TextLayoutManager: NSTextStorageDelegate {
     ///   - location: The location the string is being inserted into.
     private func applyLineInsert(_ insertedString: NSString, at location: Int) {
         if LineEnding(line: insertedString as String) != nil {
-            if location == textStorage?.length ?? 0 {
+            if location == lineStorage.length {
                 // Insert a new line at the end of the document, need to insert a new line 'cause there's nothing to
                 // split. Also, append the new text to the last line.
                 lineStorage.update(atIndex: location, delta: insertedString.length, deltaHeight: 0.0)
@@ -96,18 +128,4 @@ extension TextLayoutManager: NSTextStorageDelegate {
             lineStorage.update(atIndex: location, delta: insertedString.length, deltaHeight: 0.0)
         }
     }
-
-    /// This method is to simplify keeping the layout manager in sync with attribute changes in the storage object.
-    /// This does not handle cases where characters have been inserted or removed from the storage.
-    /// For that, see the `willPerformEdit` method.
-    public func textStorage(
-        _ textStorage: NSTextStorage,
-        didProcessEditing editedMask: NSTextStorageEditActions,
-        range editedRange: NSRange,
-        changeInLength delta: Int
-    ) {
-        if editedMask.contains(.editedAttributes) && delta == 0 {
-            invalidateLayoutForRange(editedRange)
-        }
-    }
 }
diff --git a/Sources/CodeEditTextView/TextLayoutManager/TextLayoutManager+Public.swift b/Sources/CodeEditTextView/TextLayoutManager/TextLayoutManager+Public.swift
@@ -121,7 +121,7 @@ extension TextLayoutManager {
             return nil
         }
         if linePosition.data.lineFragments.isEmpty {
-            let newHeight = ensureLayoutFor(position: linePosition)
+            let newHeight = preparePositionForDisplay(linePosition)
             if linePosition.height != newHeight {
                 delegate?.layoutManagerHeightDidUpdate(newHeight: lineStorage.height)
             }
@@ -165,7 +165,8 @@ extension TextLayoutManager {
     ///   - line: The line to calculate rects for.
     /// - Returns: Multiple bounding rects. Will return one rect for each line fragment that overlaps the given range.
     public func rectsFor(range: NSRange) -> [CGRect] {
-        lineStorage.linesInRange(range).flatMap { self.rectsFor(range: range, in: $0) }
+        ensureLayoutUntil(range.max)
+        return lineStorage.linesInRange(range).flatMap { self.rectsFor(range: range, in: $0) }
     }
 
     /// Calculates all text bounding rects that intersect with a given range, with a given line position.
@@ -190,6 +191,7 @@ extension TextLayoutManager {
         for fragmentPosition in line.data.lineFragments.linesInRange(relativeRange) {
             guard let intersectingRange = fragmentPosition.range.intersection(relativeRange) else { continue }
             let fragmentRect = fragmentPosition.data.rectFor(range: intersectingRange)
+            guard fragmentRect.width > 0 else { continue }
             rects.append(
                 CGRect(
                     x: fragmentRect.minX + edgeInsets.left,
@@ -239,6 +241,8 @@ extension TextLayoutManager {
         // Combine the points in clockwise order
         let points = leftSidePoints + rightSidePoints
 
+        guard points.allSatisfy({ $0.x.isFinite && $0.y.isFinite }) else { return nil }
+
         // Close the path
         if let firstPoint = points.first {
             return NSBezierPath.smoothPath(points + [firstPoint], radius: cornerRadius)
@@ -286,7 +290,7 @@ extension TextLayoutManager {
         for linePosition in lineStorage.linesInRange(
             NSRange(start: startingLinePosition.range.location, end: linePosition.range.max)
         ) {
-            let height = ensureLayoutFor(position: linePosition)
+            let height = preparePositionForDisplay(linePosition)
             if height != linePosition.height {
                 lineStorage.update(
                     atIndex: linePosition.range.location,

diff --git a/Sources/CodeEditTextView/TextLayoutManager/TextLayoutManager+Transaction.swift b/Sources/CodeEditTextView/TextLayoutManager/TextLayoutManager+Transaction.swift
diff --git a/Sources/CodeEditTextView/TextLayoutManager/TextLayoutManager+ensureLayout.swift b/Sources/CodeEditTextView/TextLayoutManager/TextLayoutManager+ensureLayout.swift
@@ -8,9 +8,10 @@
 import Foundation
 
 extension TextLayoutManager {
-    /// Forces layout calculation for all lines up to and including the given offset.
-    /// - Parameter offset: The offset to ensure layout until.
-    package func ensureLayoutFor(position: TextLineStorage<TextLine>.TextLinePosition) -> CGFloat {
+    /// Invalidates and prepares a line position for display.
+    /// - Parameter position: The line position to prepare.
+    /// - Returns: The height of the newly laid out line and all it's fragments.
+    package func preparePositionForDisplay(_ position: TextLineStorage<TextLine>.TextLinePosition) -> CGFloat {
         guard let textStorage else { return 0 }
         let displayData = TextLine.DisplayData(
             maxWidth: maxLineLayoutWidth,

diff --git a/Sources/CodeEditTextView/TextLayoutManager/TextLayoutManager.swift b/Sources/CodeEditTextView/TextLayoutManager/TextLayoutManager.swift
@@ -199,8 +199,6 @@ public class TextLayoutManager: NSObject {
     /// ``TextLayoutManager/estimateLineHeight()`` is called.
     private var _estimateLineHeight: CGFloat?
 
-    // MARK: - Layout
-
     /// Asserts that the caller is not in an active layout pass.
     /// See docs on ``isInLayout`` for more details.
     private func assertNotInLayout() {
@@ -209,6 +207,8 @@ public class TextLayoutManager: NSObject {
         #endif
     }
 
+    // MARK: - Layout
+
     /// Lays out all visible lines
     func layoutLines(in rect: NSRect? = nil) { // swiftlint:disable:this function_body_length
         assertNotInLayout()
@@ -217,9 +217,15 @@ public class TextLayoutManager: NSObject {
               let textStorage else {
             return
         }
+
+        // The macOS may call `layout` on the textView while we're laying out fragment views. This ensures the view
+        // tree modifications caused by this method are atomic, so macOS won't call `layout` while we're already doing
+        // that
+        CATransaction.begin()
         #if DEBUG
         isInLayout = true
         #endif
+
         let minY = max(visibleRect.minY - verticalLayoutPadding, 0)
         let maxY = max(visibleRect.maxY + verticalLayoutPadding, 0)
         let originalHeight = lineStorage.height
@@ -265,16 +271,17 @@ public class TextLayoutManager: NSObject {
             newVisibleLines.insert(linePosition.data.id)
         }
 
+        #if DEBUG
+        isInLayout = false
+        #endif
+        CATransaction.commit()
+
         // Enqueue any lines not used in this layout pass.
         viewReuseQueue.enqueueViews(notInSet: usedFragmentIDs)
 
         // Update the visible lines with the new set.
         visibleLineIds = newVisibleLines
 
-        #if DEBUG
-        isInLayout = false
-        #endif
-
         // These are fine to update outside of `isInLayout` as our internal data structures are finalized at this point
         // so laying out again won't break our line storage or visible line.
 

diff --git a/Sources/CodeEditTextView/TextSelectionManager/TextSelectionManager.swift b/Sources/CodeEditTextView/TextSelectionManager/TextSelectionManager.swift
@@ -86,6 +86,8 @@ public class TextSelectionManager: NSObject {
     /// Set the selected ranges to new ranges. Overrides any existing selections.
     /// - Parameter range: The selected ranges to set.
     public func setSelectedRanges(_ ranges: [NSRange]) {
+        let oldRanges = textSelections.map(\.range)
+
         textSelections.forEach { $0.view?.removeFromSuperview() }
         // Remove duplicates, invalid ranges, update suggested X position.
         textSelections = Set(ranges)
@@ -99,8 +101,11 @@ public class TextSelectionManager: NSObject {
                 return selection
             }
         updateSelectionViews()
-        NotificationCenter.default.post(Notification(name: Self.selectionChangedNotification, object: self))
         delegate?.setNeedsDisplay()
+
+        if oldRanges != textSelections.map(\.range) {
+            NotificationCenter.default.post(Notification(name: Self.selectionChangedNotification, object: self))
+        }
     }
 
     /// Append a new selected range to the existing ones.

diff --git a/Sources/CodeEditTextView/TextView/TextView+ReplaceCharacters.swift b/Sources/CodeEditTextView/TextView/TextView+ReplaceCharacters.swift
@@ -16,7 +16,6 @@ extension TextView {
     public func replaceCharacters(in ranges: [NSRange], with string: String) {
         guard isEditable else { return }
         NotificationCenter.default.post(name: Self.textWillChangeNotification, object: self)
-        layoutManager.beginTransaction()
         textStorage.beginEditing()
 
         // Can't insert an empty string into an empty range. One must be not empty
@@ -25,7 +24,6 @@ extension TextView {
         (delegate?.textView(self, shouldReplaceContentsIn: range, with: string) ?? true) {
             delegate?.textView(self, willReplaceContentsIn: range, with: string)
 
-            layoutManager.willReplaceCharactersInRange(range: range, with: string)
             _undoManager?.registerMutation(
                 TextMutation(string: string as String, range: range, limit: textStorage.length)
             )
@@ -39,7 +37,6 @@ extension TextView {
         }
 
         textStorage.endEditing()
-        layoutManager.endTransaction()
         selectionManager.notifyAfterEdit()
         NotificationCenter.default.post(name: Self.textDidChangeNotification, object: self)
 

diff --git a/Sources/CodeEditTextView/TextView/TextView.swift b/Sources/CodeEditTextView/TextView/TextView.swift
@@ -58,7 +58,6 @@ public class TextView: NSView, NSTextContent {
             textStorage.string
         }
         set {
-            layoutManager.willReplaceCharactersInRange(range: documentRange, with: newValue)
             textStorage.setAttributedString(NSAttributedString(string: newValue, attributes: typingAttributes))
         }
     }
@@ -339,6 +338,7 @@ public class TextView: NSView, NSTextContent {
 
         layoutManager = setUpLayoutManager(lineHeightMultiplier: lineHeightMultiplier, wrapLines: wrapLines)
         storageDelegate.addDelegate(layoutManager)
+
         selectionManager = setUpSelectionManager()
         selectionManager.useSystemCursor = useSystemCursor
 

diff --git a/Sources/CodeEditTextView/Utils/CEUndoManager.swift b/Sources/CodeEditTextView/Utils/CEUndoManager.swift
@@ -173,19 +173,13 @@ public class CEUndoManager {
 
     /// Groups all incoming mutations.
     public func beginUndoGrouping() {
-        guard !isGrouping else {
-            assertionFailure("UndoManager already in a group. Call `beginUndoGrouping` before this can be called.")
-            return
-        }
+        guard !isGrouping else { return }
         isGrouping = true
     }
 
     /// Stops grouping all incoming mutations.
     public func endUndoGrouping() {
-        guard isGrouping else {
-            assertionFailure("UndoManager not in a group. Call `endUndoGrouping` before this can be called.")
-            return
-        }
+        guard isGrouping else { return }
         isGrouping = false
     }
 

diff --git a/Tests/CodeEditTextViewTests/EmphasisManagerTests.swift b/Tests/CodeEditTextViewTests/EmphasisManagerTests.swift
@@ -4,7 +4,8 @@ import Foundation
 
 @Suite()
 struct EmphasisManagerTests {
-    @Test() @MainActor
+    @Test()
+    @MainActor
     func testFlashEmphasisLayersNotLeaked() {
         // Ensure layers are not leaked when switching from flash emphasis to any other emphasis type.
         let textView = TextView(string: "Lorem Ipsum")