Initial checkin

IDE/src/util/SettingHistoryManager.bf

@@ -0,0 +1,85 @@
+using System;
+using System.Collections.Generic;
+
+namespace IDE.util
+{
+	class SettingHistoryManager
+	{
+		public List<PropertyBag> mHistory = new .() ~ DeleteContainerAndItems!(_);
+		public int mHistoryIdx;
+		public PropertyBag mEmptyEnd ~ delete _;
+
+		public this(bool endOnEmpty)
+		{
+			if (endOnEmpty)
+				mEmptyEnd = new PropertyBag();
+		}
+
+		public bool HasPrev()
+		{
+			if ((mHistoryIdx == 0) || (mHistory == null))
+				return false;
+			return true;
+		}
+
+		public PropertyBag GetPrev()
+		{
+			if ((mHistoryIdx == 0) || (mHistory == null))
+				return null;
+			return mHistory[--mHistoryIdx];
+		}
+
+		public bool HasNext()
+		{
+			if (mHistoryIdx >= mHistory.Count - 1)
+			{
+				if (mEmptyEnd != null)
+					return true;
+				return false;
+			}
+			return true;
+		}
+
+		public PropertyBag GetNext()
+		{
+			if ((mHistoryIdx >= mHistory.Count - 1) && (mEmptyEnd != null))
+			{
+				if (mHistoryIdx == mHistory.Count - 1)
+					mHistoryIdx++;
+				return mEmptyEnd;
+			}
+
+			if (mHistoryIdx >= mHistory.Count - 1)
+				return null;
+			return mHistory[++mHistoryIdx];
+		}
+
+		public void Add(PropertyBag propertyBag)
+		{
+			while (mHistoryIdx < mHistory.Count - 1)
+			{
+				var prevEntry = mHistory.Back;
+				mHistory.PopBack();
+				delete prevEntry;
+			}
+
+			if (!mHistory.IsEmpty)
+			{
+				// Ignore duplicate
+				if (propertyBag == mHistory.Back)
+				{
+					delete propertyBag;
+					return;
+				}
+			}
+
+			mHistory.Add(propertyBag);
+			mHistoryIdx++;
+		}
+
+		public void ToEnd()
+		{
+			mHistoryIdx = mHistory.Count;
+		}
+	}
+}