Merge pull request #8741 from peppy/limit-max-history

Limit upper number of editor beatmap states saved to 50

osu.Game.Tests/Editor/EditorChangeHandlerTest.cs

@@ -0,0 +1,71 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using NUnit.Framework;
+using osu.Game.Beatmaps;
+using osu.Game.Screens.Edit;
+
+namespace osu.Game.Tests.Editor
+{
+    [TestFixture]
+    public class EditorChangeHandlerTest
+    {
+        [Test]
+        public void TestSaveRestoreState()
+        {
+            var handler = new EditorChangeHandler(new EditorBeatmap(new Beatmap()));
+
+            Assert.That(handler.HasUndoState, Is.False);
+
+            handler.SaveState();
+
+            Assert.That(handler.HasUndoState, Is.True);
+
+            handler.RestoreState(-1);
+
+            Assert.That(handler.HasUndoState, Is.False);
+        }
+
+        [Test]
+        public void TestMaxStatesSaved()
+        {
+            var handler = new EditorChangeHandler(new EditorBeatmap(new Beatmap()));
+
+            Assert.That(handler.HasUndoState, Is.False);
+
+            for (int i = 0; i < EditorChangeHandler.MAX_SAVED_STATES; i++)
+                handler.SaveState();
+
+            Assert.That(handler.HasUndoState, Is.True);
+
+            for (int i = 0; i < EditorChangeHandler.MAX_SAVED_STATES; i++)
+            {
+                Assert.That(handler.HasUndoState, Is.True);
+                handler.RestoreState(-1);
+            }
+
+            Assert.That(handler.HasUndoState, Is.False);
+        }
+
+        [Test]
+        public void TestMaxStatesExceeded()
+        {
+            var handler = new EditorChangeHandler(new EditorBeatmap(new Beatmap()));
+
+            Assert.That(handler.HasUndoState, Is.False);
+
+            for (int i = 0; i < EditorChangeHandler.MAX_SAVED_STATES * 2; i++)
+                handler.SaveState();
+
+            Assert.That(handler.HasUndoState, Is.True);
+
+            for (int i = 0; i < EditorChangeHandler.MAX_SAVED_STATES; i++)
+            {
+                Assert.That(handler.HasUndoState, Is.True);
+                handler.RestoreState(-1);
+            }
+
+            Assert.That(handler.HasUndoState, Is.False);
+        }
+    }
+}

osu.Game/Screens/Edit/EditorChangeHandler.cs

@@ -25,6 +25,8 @@ namespace osu.Game.Screens.Edit
         private int bulkChangesStarted;
         private bool isRestoring;
 
+        public const int MAX_SAVED_STATES = 50;
+
         /// <summary>
         /// Creates a new <see cref="EditorChangeHandler"/>.
         /// </summary>
@@ -43,6 +45,8 @@ namespace osu.Game.Screens.Edit
             SaveState();
         }
 
+        public bool HasUndoState => currentState > 0;
+
         private void hitObjectAdded(HitObject obj) => SaveState();
 
         private void hitObjectRemoved(HitObject obj) => SaveState();
@@ -74,6 +78,9 @@ namespace osu.Game.Screens.Edit
             if (currentState < savedStates.Count - 1)
                 savedStates.RemoveRange(currentState + 1, savedStates.Count - currentState - 1);
 
+            if (savedStates.Count > MAX_SAVED_STATES)
+                savedStates.RemoveAt(0);
+
             using (var stream = new MemoryStream())
             {
                 using (var sw = new StreamWriter(stream, Encoding.UTF8, 1024, true))