better cleanup of socket / pipe

StackExchange.Redis/StackExchange/Redis/PhysicalConnection.cs

@@ -73,7 +73,6 @@ private static readonly Message
         private IDuplexPipe _ioPipe;
 
         private Socket _socket;
-        private SocketAsyncEventArgs _socketArgs;
 
         public PhysicalConnection(PhysicalBridge bridge)
         {
@@ -105,16 +104,19 @@ internal async void BeginConnectAsync(TextWriter log)
 
             bridge.Multiplexer.LogLocked(log, "BeginConnect: {0}", Format.ToString(endpoint));
 
+            CancellationTokenSource timeoutSource = null;
+            try
+            {
                 var awaitable = new SocketAwaitable();
-            _socketArgs = new SocketAsyncEventArgs
+                
+                using (var _socketArgs = new SocketAsyncEventArgs
                 {
                     UserToken = awaitable,
                     RemoteEndPoint = endpoint,
-            };
-            _socketArgs.Completed += SocketAwaitable.Callback;
-            CancellationTokenSource timeoutSource = null;
-            try
+                })
                 {
+                    _socketArgs.Completed += SocketAwaitable.Callback;
+                    
                     if (_socket.ConnectAsync(_socketArgs))
                     {   // asynchronous operation is pending
                         timeoutSource = ConfigureTimeout(_socketArgs, bridge.Multiplexer.RawConfig.ConnectTimeout);
@@ -123,7 +125,7 @@ internal async void BeginConnectAsync(TextWriter log)
                     {   // completed synchronously
                         SocketAwaitable.OnCompleted(_socketArgs);
                     }
-
+                }
                 // Complete connection
                 try
                 {
@@ -132,8 +134,11 @@ internal async void BeginConnectAsync(TextWriter log)
                     if (ignoreConnect) return;
 
                     await awaitable; // wait for the connect to complete or fail (will throw)
-                    timeoutSource?.Cancel();
-
+                    if (timeoutSource != null)
+                    {
+                        timeoutSource.Cancel();
+                        timeoutSource.Dispose();
+                    }
                     if (await ConnectedAsync(_socket, log, bridge.Multiplexer.SocketManager).ForAwait())
                     {
                         bridge.Multiplexer.LogLocked(log, "Starting read");
@@ -181,6 +186,10 @@ internal async void BeginConnectAsync(TextWriter log)
                 }
                 throw;
             }
+            finally
+            {
+                if (timeoutSource != null) try { timeoutSource.Dispose(); } catch { }
+            }
         }
 
         private static CancellationTokenSource ConfigureTimeout(SocketAsyncEventArgs args, int timeoutMilliseconds)
@@ -235,21 +244,12 @@ private bool IncludeDetailInExceptions
         [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2202:Do not dispose objects multiple times")]
         internal void Shutdown()
         {
+            var ioPipe = _ioPipe;
             var socket = _socket;
+            _ioPipe = null;
             socket = null;
-            if (socket != null)
-            {
-                try { socket.Shutdown(SocketShutdown.Both); } catch { }
-                try { socket.Close(); } catch { }
-                try { socket.Dispose(); } catch { }
-            }
-            try { using (_socketArgs) { } } catch { }
-        }
 
-        public void Dispose()
-        {
-            var ioPipe = _ioPipe;
-            _ioPipe = null;
+
             if (ioPipe != null)
             {
                 Trace("Disconnecting...");
@@ -257,18 +257,28 @@ public void Dispose()
                 try { ioPipe.Input?.Complete(); } catch { }
                 try { ioPipe.Output?.CancelPendingFlush(); } catch { }
                 try { ioPipe.Output?.Complete(); } catch { }
-                ioPipe.Output?.Complete();
-            }
+
                 try { using (ioPipe as IDisposable) { } } catch { }
+            }            
             
-            if (_socket != null)
+            if (socket != null)
             {
+                try { socket.Shutdown(SocketShutdown.Both); } catch { }
+                try { socket.Close(); } catch { }
+                try { socket.Dispose(); } catch { }
+            }
+        }
+
+        public void Dispose()
+        {
+            bool markDisposed = _socket != null;
             Shutdown();
+            if (markDisposed)
+            {
                 Trace("Disconnected");
                 RecordConnectionFailed(ConnectionFailureType.ConnectionDisposed);
             }
             OnCloseEcho();
-
             GC.SuppressFinalize(this);
         }