1 files changed, 185 insertions, 0 deletions

diff --git a/OpenSim/Framework/Communications/GenericAsyncResult.cs b/OpenSim/Framework/Communications/GenericAsyncResult.cs
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+++ b/OpenSim/Framework/Communications/GenericAsyncResult.cs
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+/*
+ * Copyright (c) Contributors, http://opensimulator.org/
+ * See CONTRIBUTORS.TXT for a full list of copyright holders.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the OpenSimulator Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+using System;
+using System.Threading;
+
+namespace OpenSim.Framework.Communications
+{
+    internal class SimpleAsyncResult : IAsyncResult
+    {
+        private readonly AsyncCallback m_callback;
+
+        /// <summary>
+        /// Is process completed?
+        /// </summary>
+        /// <remarks>Should really be boolean, but VolatileRead has no boolean method</remarks>
+        private byte m_completed;
+
+        /// <summary>
+        /// Did process complete synchronously?
+        /// </summary>
+        /// <remarks>I have a hard time imagining a scenario where this is the case, again, same issue about
+        /// booleans and VolatileRead as m_completed
+        /// </remarks>
+        private byte m_completedSynchronously;
+
+        private readonly object m_asyncState;
+        private ManualResetEvent m_waitHandle;
+        private Exception m_exception;
+
+        internal SimpleAsyncResult(AsyncCallback cb, object state)
+        {
+            m_callback = cb;
+            m_asyncState = state;
+            m_completed = 0;
+            m_completedSynchronously = 1;
+        }
+
+        #region IAsyncResult Members
+
+        public object AsyncState
+        {
+            get { return m_asyncState; }
+        }
+
+        public WaitHandle AsyncWaitHandle
+        {
+            get
+            {
+                if (m_waitHandle == null)
+                {
+                    bool done = IsCompleted;
+                    ManualResetEvent mre = new ManualResetEvent(done);
+                    if (Interlocked.CompareExchange(ref m_waitHandle, mre, null) != null)
+                    {
+                        mre.Close();
+                    }
+                    else
+                    {
+                        if (!done && IsCompleted)
+                        {
+                            m_waitHandle.Set();
+                        }
+                    }
+                }
+                
+                return m_waitHandle;
+            }
+        }
+
+
+        public bool CompletedSynchronously
+        {
+            get { return Thread.VolatileRead(ref m_completedSynchronously) == 1; }
+        }
+
+
+        public bool IsCompleted
+        {
+            get { return Thread.VolatileRead(ref m_completed) == 1; }
+        }
+
+        #endregion
+
+        #region class Methods
+
+        internal void SetAsCompleted(bool completedSynchronously)
+        {
+            m_completed = 1;
+            if (completedSynchronously)
+                m_completedSynchronously = 1;
+            else
+                m_completedSynchronously = 0;
+
+            SignalCompletion();
+        }
+
+        internal void HandleException(Exception e, bool completedSynchronously)
+        {
+            m_completed = 1;
+            if (completedSynchronously)
+                m_completedSynchronously = 1;
+            else
+                m_completedSynchronously = 0;
+            m_exception = e;
+
+            SignalCompletion();
+        }
+
+        private void SignalCompletion()
+        {
+            if (m_waitHandle != null) m_waitHandle.Set();
+
+            if (m_callback != null) m_callback(this);
+        }
+
+        public void EndInvoke()
+        {
+            // This method assumes that only 1 thread calls EndInvoke
+            if (!IsCompleted)
+            {
+                // If the operation isn't done, wait for it
+                AsyncWaitHandle.WaitOne();
+                AsyncWaitHandle.Close();
+                m_waitHandle.Close();
+                m_waitHandle = null; // Allow early GC
+            }
+
+            // Operation is done: if an exception occured, throw it
+            if (m_exception != null) throw m_exception;
+        }
+
+        #endregion
+    }
+
+    internal class AsyncResult<T> : SimpleAsyncResult
+    {
+        private T m_result = default(T);
+
+        public AsyncResult(AsyncCallback asyncCallback, Object state) :
+            base(asyncCallback, state)
+        {
+        }
+
+        public void SetAsCompleted(T result, bool completedSynchronously)
+        {
+            // Save the asynchronous operation's result
+            m_result = result;
+
+            // Tell the base class that the operation completed
+            // sucessfully (no exception)
+            base.SetAsCompleted(completedSynchronously);
+        }
+
+        public new T EndInvoke()
+        {
+            base.EndInvoke();
+            return m_result;
+        }
+    }
+}
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