port from perforce

intromat/Intromat/ViewModels/UndoItemGroup.cs

@@ -0,0 +1,36 @@
+using System.Collections.Generic;
+using System.Linq;
+using Intromat.Interfaces;
+using ReactiveUI;
+
+namespace Intromat.ViewModels
+{
+    public class UndoItemGroup : ReactiveObject, IUndoItem
+    {
+        public List<IUndoItem> Items = new();
+
+        public UndoItemGroup(IFile file)
+        {
+            File = file;
+        }
+
+        public IFile File { get; }
+
+        public void Redo()
+        {
+            foreach (var item in Items)
+                item.Redo();
+        }
+
+        public void Undo()
+        {
+            foreach (var item in Items.Reverse<IUndoItem>())
+                item.Undo();
+        }
+
+        public void Push(IUndoItem item)
+        {
+            Items.Add(item);
+        }
+    }
+}