From c9a66c0d07a8a89267355133a0eb8caead972c88 Mon Sep 17 00:00:00 2001
From: smoogipoo <smoogipoo@smgi.me>
Date: Thu, 5 Dec 2019 18:31:28 +0900
Subject: [PATCH] Expose a version to indicate path changes

---
 osu.Game/Rulesets/Objects/SliderPath.cs | 25 ++++++++++++++++++-------
 1 file changed, 18 insertions(+), 7 deletions(-)

diff --git a/osu.Game/Rulesets/Objects/SliderPath.cs b/osu.Game/Rulesets/Objects/SliderPath.cs
index bbeb03992e..6ad5d2f1c3 100644
--- a/osu.Game/Rulesets/Objects/SliderPath.cs
+++ b/osu.Game/Rulesets/Objects/SliderPath.cs
@@ -16,6 +16,13 @@ namespace osu.Game.Rulesets.Objects
 {
     public class SliderPath
     {
+        /// <summary>
+        /// The current version of this <see cref="SliderPath"/>. Updated when any change to the path occurs.
+        /// </summary>
+        public IBindable<int> Version => version;
+
+        private readonly Bindable<int> version = new Bindable<int>();
+
         /// <summary>
         /// The user-set distance of the path. If non-null, <see cref="Distance"/> will match this value,
         /// and the path will be shortened/lengthened to match this length.
@@ -39,25 +46,23 @@ namespace osu.Game.Rulesets.Objects
         /// </summary>
         public SliderPath()
         {
-            ExpectedDistance.ValueChanged += _ => pathCache.Invalidate();
+            ExpectedDistance.ValueChanged += _ => invalidate();
 
             ControlPoints.ItemsAdded += items =>
             {
                 foreach (var c in items)
-                    c.Changed += onControlPointChanged;
+                    c.Changed += invalidate;
 
-                onControlPointChanged();
+                invalidate();
             };
 
             ControlPoints.ItemsRemoved += items =>
             {
                 foreach (var c in items)
-                    c.Changed -= onControlPointChanged;
+                    c.Changed -= invalidate;
 
-                onControlPointChanged();
+                invalidate();
             };
-
-            void onControlPointChanged() => pathCache.Invalidate();
         }
 
         /// <summary>
@@ -141,6 +146,12 @@ namespace osu.Game.Rulesets.Objects
             return interpolateVertices(indexOfDistance(d), d);
         }
 
+        private void invalidate()
+        {
+            pathCache.Invalidate();
+            version.Value++;
+        }
+
         private void ensureValid()
         {
             if (pathCache.IsValid)