Clear undo buffer when undo buffer is saved. Breaks /redo.

Drawing/DrawOps/RedoDrawOp.cs

@@ -74,7 +74,6 @@ namespace MCGalaxy.Drawing.Ops {
                 buffer.CheckIfSend(true);
                 node = node.Prev;
             }
-            return;
         }
     }
 }

Player/Player.cs

@@ -123,14 +123,9 @@ namespace MCGalaxy {
                 ecos.money = money;
                 Economy.UpdateEcoStats(ecos);
             }
+            
             Server.zombie.SaveZombieStats(this);
-
-            try {
-                SaveUndo(this);
-            } catch (Exception e) {
-                Server.s.Log("Error saving undo data.");
-                Server.ErrorLog(e);
-            }
+            SaveUndo(this);
         }
 
         #region == GLOBAL MESSAGES ==

Player/Undo/UndoCache.cs

@@ -39,25 +39,30 @@ namespace MCGalaxy.Util {
         /// <summary> Used to sychronise clearing an undo cache. </summary>
         public ReaderWriterLockSlim ClearLock = new ReaderWriterLockSlim();
         
+        /// <summary> Used to sychronise adding to an undo cache. </summary>
+        public object AddLock = new object();
+        
         public const int TimeDeltaMax = (1 << 13) - 1;
         
         /// <summary> Appends an item to the cache. </summary>
         public void Add(Level lvl, Player.UndoPos item) {
-            DateTime time = Server.StartTime.AddTicks(item.timeDelta * TimeSpan.TicksPerSecond);
-            if (Tail == null) {
-                Tail = UndoCacheNode.Make(lvl, time); Head = Tail;
-            }
+            lock (AddLock) {
+                DateTime time = Server.StartTime.AddTicks(item.timeDelta * TimeSpan.TicksPerSecond);
+                if (Tail == null) {
+                    Tail = UndoCacheNode.Make(lvl, time); Head = Tail;
+                }
 
-            if (lvl.name != Tail.MapName || lvl.Width != Tail.Width || lvl.Height != Tail.Height ||
-                lvl.Length != Tail.Length || Math.Abs((time - Tail.BaseTime).TotalSeconds) > TimeDeltaMax) {
-                UndoCacheNode node = UndoCacheNode.Make(lvl, time);
-                Tail.Next = node; node.Prev = Tail;
-                Tail = node;
+                if (lvl.name != Tail.MapName || lvl.Width != Tail.Width || lvl.Height != Tail.Height ||
+                    lvl.Length != Tail.Length || Math.Abs((time - Tail.BaseTime).TotalSeconds) > TimeDeltaMax) {
+                    UndoCacheNode node = UndoCacheNode.Make(lvl, time);
+                    Tail.Next = node; node.Prev = Tail;
+                    Tail = node;
+                }
+                
+                short timeDiff = (short)(time - Tail.BaseTime).TotalSeconds;
+                Tail.Items.Add(UndoCacheItem.Make(Tail, timeDiff, ref item));
+                Count++;
             }
-            
-            short timeDiff = (short)(time - Tail.BaseTime).TotalSeconds;
-            Tail.Items.Add(UndoCacheItem.Make(Tail, timeDiff, ref item));
-            Count++;
         }
         
         /// <summary> Removes all items from the cache and resets the state to default. </summary>
@@ -81,7 +86,7 @@ namespace MCGalaxy.Util {
         public int Width, Height, Length;
         public DateTime BaseTime;
         
-        public UndoCacheNode Prev;
+        public UndoCacheNode Prev, Next;
         public List<UndoCacheItem> Items = new List<UndoCacheItem>();
         
         public static UndoCacheNode Make(Level lvl, DateTime time) {

Player/Undo/UndoFile.cs

@@ -64,6 +64,11 @@ namespace MCGalaxy.Util {
             using (IDisposable locker = cache.ClearLock.AccquireReadLock()) {
                 NewFormat.SaveUndoData(cache, path);
             }
+
+            using (IDisposable locker = cache.ClearLock.AccquireWriteLock()) {
+            	lock (cache.AddLock)
+            	    cache.Clear();
+            }
         }
         
         public static void UndoPlayer(Player p, string target, Vec3S32[] marks, DateTime start, ref bool FoundUser) {

Player/Undo/UndoFileCBin.cs

@@ -70,12 +70,11 @@ namespace MCGalaxy.Util {
         }
         
         protected override void SaveUndoData(UndoCache buffer, string path) {
-            // TODO: should be writing Head first??
             using (FileStream fs = File.Create(path)) {
                 BinaryWriter w = new BinaryWriter(fs);
                 long entriesPos = 0;
                 ChunkHeader last = default(ChunkHeader);
-                UndoCacheNode node = buffer.Tail;
+                UndoCacheNode node = buffer.Head;
                 
                 while (node != null) {
                     List<UndoCacheItem> items = node.Items;
@@ -95,7 +94,7 @@ namespace MCGalaxy.Util {
                     }
                     if (last.Entries > 0)
                         WriteChunkEntries(w, last.Entries, entriesPos);
-                    node = node.Prev;
+                    node = node.Next;
                 }
             }
         }