Update View When Folds Change

Author: thecoolwinter

Sources/CodeEditSourceEditor/Gutter/LineFolding/FoldingRibbonView.swift

@@ -8,6 +8,7 @@
 import Foundation
 import AppKit
 import CodeEditTextView
+import Combine
 
 #warning("Replace before release")
 fileprivate let demoFoldProvider = IndentationLineFoldProvider()
@@ -83,6 +84,8 @@ class FoldingRibbonView: NSView {
         }
     }.cgColor
 
+    private var foldUpdateCancellable: AnyCancellable?
+
     override public var isFlipped: Bool {
         true
     }
@@ -96,12 +99,20 @@ class FoldingRibbonView: NSView {
         super.init(frame: .zero)
         layerContentsRedrawPolicy = .onSetNeedsDisplay
         clipsToBounds = false
+
+        foldUpdateCancellable = model.foldsUpdatedPublisher.sink {
+            self.needsDisplay = true
+        }
     }
 
     required init?(coder: NSCoder) {
         fatalError("init(coder:) has not been implemented")
     }
 
+    deinit {
+        foldUpdateCancellable?.cancel()
+    }
+
     // MARK: - Hover
 
     override func updateTrackingAreas() {

Sources/CodeEditSourceEditor/Gutter/LineFolding/LineFoldingModel.swift

@@ -7,6 +7,7 @@
 
 import AppKit
 import CodeEditTextView
+import Combine
 
 /// # Basic Premise
 ///
@@ -25,6 +26,8 @@ class LineFoldingModel: NSObject, NSTextStorageDelegate {
     weak var foldProvider: LineFoldProvider?
     weak var textView: TextView?
 
+    lazy var foldsUpdatedPublisher = PassthroughSubject<Void, Never>()
+
     init(textView: TextView, foldProvider: LineFoldProvider?) {
         self.textView = textView
         self.foldProvider = foldProvider
@@ -64,25 +67,25 @@ class LineFoldingModel: NSObject, NSTextStorageDelegate {
                     parent: currentFold,
                     subFolds: []
                 )
-                if currentDepth == 0 {
+
+                if currentFold == nil {
                     foldCache.append(newFold)
+                } else {
+                    currentFold?.subFolds.append(newFold)
                 }
-                currentFold?.subFolds.append(newFold)
                 currentFold = newFold
             } else if foldDepth < currentDepth {
                 // End this fold
                 if let fold = currentFold {
                     fold.lineRange = fold.lineRange.lowerBound...linePosition.index
-
-                    if foldDepth == 0 {
-                        currentFold = nil
-                    }
                 }
                 currentFold = currentFold?.parent
             }
 
             currentDepth = foldDepth
         }
+
+        foldsUpdatedPublisher.send()
     }
 
     func invalidateLine(lineNumber: Int) {