1 files changed, 108 insertions, 0 deletions

diff --git a/OpenSim/Framework/Util.cs b/OpenSim/Framework/Util.cs
index ada4e89..7f0850f 100644
--- a/OpenSim/Framework/Util.cs
+++ b/OpenSim/Framework/Util.cs
@@ -2233,4 +2233,112 @@ namespace OpenSim.Framework
             return str.Replace("_", "\\_").Replace("%", "\\%");
         }
     }
+
+    public class DoubleQueue<T> where T:class
+    {
+        private Queue<T> m_lowQueue = new Queue<T>();
+        private Queue<T> m_highQueue = new Queue<T>();
+
+        private object m_syncRoot = new object();
+        private Semaphore m_s = new Semaphore(0, 1);
+
+        public DoubleQueue()
+        {
+        }
+
+        public virtual int Count
+        {
+            get { return m_highQueue.Count + m_lowQueue.Count; }
+        }
+
+        public virtual void Enqueue(T data)
+        {
+            Enqueue(m_lowQueue, data);
+        }
+
+        public virtual void EnqueueLow(T data)
+        {
+            Enqueue(m_lowQueue, data);
+        }
+
+        public virtual void EnqueueHigh(T data)
+        {
+            Enqueue(m_highQueue, data);
+        }
+
+        private void Enqueue(Queue<T> q, T data)
+        {
+            lock (m_syncRoot)
+            {
+                m_lowQueue.Enqueue(data);
+                m_s.WaitOne(0);
+                m_s.Release();
+            }
+        }
+
+        public virtual T Dequeue()
+        {
+            return Dequeue(Timeout.Infinite);
+        }
+
+        public virtual T Dequeue(int tmo)
+        {
+            return Dequeue(TimeSpan.FromMilliseconds(tmo));
+        }
+
+        public virtual T Dequeue(TimeSpan wait)
+        {
+            T res = null;
+
+            if (!Dequeue(wait, ref res))
+                return null;
+
+            return res;
+        }
+
+        public bool Dequeue(int timeout, ref T res)
+        {
+            return Dequeue(TimeSpan.FromMilliseconds(timeout), ref res);
+        }
+
+        public bool Dequeue(TimeSpan wait, ref T res)
+        {
+            if (!m_s.WaitOne(wait))
+                return false;
+
+            lock (m_syncRoot)
+            {
+                if (m_highQueue.Count > 0)
+                    res = m_highQueue.Dequeue();
+                else
+                    res = m_lowQueue.Dequeue();
+
+                if (m_highQueue.Count == 0 && m_lowQueue.Count == 0)
+                    return true;
+
+                try
+                {
+                    m_s.Release();
+                }
+                catch
+                {
+                }
+
+                return true;
+            }
+        }
+
+        public virtual void Clear()
+        {
+
+            lock (m_syncRoot)
+            {
+                // Make sure sem count is 0
+                m_s.WaitOne(0);
+
+                m_lowQueue.Clear();
+                m_highQueue.Clear();
+            }
+        }
+    }
 }