Removed SNIMarsManager, and modified TdsParserStateObjectManaged so t…

…hat it manages its own SNIMarsConnection if MARS is enabled. This prevents SNIMarsConnections from accumulating forever in a static SNIMarsManager singleton. (#22709) (#23357)

src/System.Data.SqlClient/src/System.Data.SqlClient.csproj

@@ -161,7 +161,6 @@
     <Compile Include="System\Data\SqlClient\SNI\SNILoadHandle.cs" />
     <Compile Include="System\Data\SqlClient\SNI\SNIMarsConnection.cs" />
     <Compile Include="System\Data\SqlClient\SNI\SNIMarsHandle.cs" />
-    <Compile Include="System\Data\SqlClient\SNI\SNIMarsManager.cs" />
     <Compile Include="System\Data\SqlClient\SNI\SNIMarsQueuedPacket.cs" />
     <Compile Include="System\Data\SqlClient\SNI\SNINpHandle.cs" />
     <Compile Include="System\Data\SqlClient\SNI\SNIPacket.cs" />

src/System.Data.SqlClient/src/System/Data/SqlClient/SNI/SNIMarsConnection.cs

@@ -45,7 +45,7 @@ public SNIMarsConnection(SNIHandle lowerHandle)
             _lowerHandle.SetAsyncCallbacks(HandleReceiveComplete, HandleSendComplete);
         }
 
-        public SNIMarsHandle CreateSession(object callbackObject, bool async)
+        public SNIMarsHandle CreateMarsSession(object callbackObject, bool async)
         {
             lock (this)
             {

src/System.Data.SqlClient/src/System/Data/SqlClient/SNI/SNIProxy.cs

@@ -38,21 +38,6 @@ public void Terminate()
         {
         }
 
-        /// <summary>
-        /// Enable MARS support on a connection
-        /// </summary>
-        /// <param name="handle">Connection handle</param>
-        /// <returns>SNI error code</returns>
-        public uint EnableMars(SNIHandle handle)
-        {
-            if (SNIMarsManager.Singleton.CreateMarsConnection(handle) == TdsEnums.SNI_SUCCESS_IO_PENDING)
-            {
-                return TdsEnums.SNI_SUCCESS;
-            }
-
-            return TdsEnums.SNI_ERROR;
-        }
-
         /// <summary>
         /// Enable SSL on a connection
         /// </summary>
@@ -432,20 +417,6 @@ private SNINpHandle CreateNpHandle(DataSource details, long timerExpire, object
             return new SNINpHandle(details.PipeHostName, details.PipeName, timerExpire, callbackObject);
         }
 
-        /// <summary>
-        /// Create MARS handle
-        /// </summary>
-        /// <param name="callbackObject">Asynchronous I/O callback object</param>
-        /// <param name="physicalConnection">SNI connection handle</param>
-        /// <param name="defaultBufferSize">Default buffer size</param>
-        /// <param name="async">Asynchronous connection</param>
-        /// <returns>SNI error status</returns>
-        public SNIHandle CreateMarsHandle(object callbackObject, SNIHandle physicalConnection, int defaultBufferSize, bool async)
-        {
-            SNIMarsConnection connection = SNIMarsManager.Singleton.GetConnection(physicalConnection);
-            return connection.CreateSession(callbackObject, async);
-        }
-
         /// <summary>
         /// Read packet asynchronously
         /// </summary>

src/System.Data.SqlClient/src/System/Data/SqlClient/TdsParserStateObjectManaged.cs

@@ -11,7 +11,7 @@ namespace System.Data.SqlClient.SNI
 {
     internal class TdsParserStateObjectManaged : TdsParserStateObject
     {
-
+        private SNIMarsConnection _marsConnection = null;
         private SNIHandle _sessionHandle = null;              // the SNI handle we're to work on
         private SNIPacket _sniPacket = null;                // Will have to re-vamp this for MARS
         internal SNIPacket _sniAsyncAttnPacket = null;                // Packet to use to send Attn
@@ -45,7 +45,13 @@ protected override void CreateSessionHandle(TdsParserStateObject physicalConnect
         {
             Debug.Assert(physicalConnection is TdsParserStateObjectManaged, "Expected a stateObject of type " + this.GetType());
             TdsParserStateObjectManaged managedSNIObject = physicalConnection as TdsParserStateObjectManaged;
-            _sessionHandle = SNIProxy.Singleton.CreateMarsHandle(this, managedSNIObject.Handle, _outBuff.Length, async);
+
+            _sessionHandle = managedSNIObject.CreateMarsSession(this, async);
+        }
+
+        internal SNIMarsHandle CreateMarsSession(object callbackObject, bool async)
+        {
+            return _marsConnection.CreateMarsSession(callbackObject, async);
         }
 
         protected override uint SNIPacketGetData(object packet, byte[] _inBuff, ref uint dataSize) => SNIProxy.Singleton.PacketGetData(packet as SNIPacket, _inBuff, ref dataSize);
@@ -84,10 +90,7 @@ internal override void Dispose()
             _sniPacket = null;
             _sessionHandle = null;
             _sniAsyncAttnPacket = null;
-
-            _sniPacket = null;
-            _sessionHandle = null;
-            _sniAsyncAttnPacket = null;
+            _marsConnection = null;
 
             DisposeCounters();
 
@@ -218,7 +221,16 @@ internal override void ClearAllWritePackets()
 
         internal override uint DisabeSsl() => SNIProxy.Singleton.DisableSsl(Handle);
 
-        internal override uint EnableMars(ref uint info) => SNIProxy.Singleton.EnableMars(Handle);
+        internal override uint EnableMars(ref uint info)
+        {
+            _marsConnection = new SNIMarsConnection(Handle);
+            if (_marsConnection.StartReceive() == TdsEnums.SNI_SUCCESS_IO_PENDING)
+            {
+                return TdsEnums.SNI_SUCCESS;
+            }
+
+            return TdsEnums.SNI_ERROR;
+        }
 
         internal override uint EnableSsl(ref uint info)=>  SNIProxy.Singleton.EnableSsl(Handle, info);