Refactor to insert FreeGcHandle

Author: edwardneal

src/Microsoft.Data.SqlClient/netcore/src/Microsoft/Data/SqlClient/TdsParserStateObject.netcore.cs

@@ -67,8 +67,6 @@ protected TdsParserStateObject(TdsParser parser, TdsParserStateObject physicalCo
         // General methods //
         /////////////////////
 
-        protected abstract void FreeGcHandle(int remaining, bool release);
-
         internal abstract uint EnableSsl(ref uint info, bool tlsFirst, string serverCertificateFilename);
 
         internal abstract uint WaitForSSLHandShakeToComplete(out int protocolVersion);
@@ -81,7 +79,9 @@ internal int DecrementPendingCallbacks(bool release)
         {
             int remaining = Interlocked.Decrement(ref _pendingCallbacks);
             SqlClientEventSource.Log.TryAdvancedTraceEvent("TdsParserStateObject.DecrementPendingCallbacks | ADV | State Object Id {0}, after decrementing _pendingCallbacks: {1}", _objectID, _pendingCallbacks);
+            
             FreeGcHandle(remaining, release);
+
             // NOTE: TdsParserSessionPool may call DecrementPendingCallbacks on a TdsParserStateObject which is already disposed
             // This is not dangerous (since the stateObj is no longer in use), but we need to add a workaround in the assert for it
             Debug.Assert((remaining == -1 && SessionHandle.IsNull) || (0 <= remaining && remaining < 3), $"_pendingCallbacks values is invalid after decrementing: {remaining}");

src/Microsoft.Data.SqlClient/netfx/src/Microsoft/Data/SqlClient/TdsParserStateObject.netfx.cs

@@ -27,7 +27,7 @@ internal partial class TdsParserStateObject
         internal SNIPacket _sniAsyncAttnPacket = null;                // Packet to use to send Attn
 
         // Async variables
-        private GCHandle _gcHandle;                                    // keeps this object alive until we're closed.
+        protected GCHandle _gcHandle;                                    // keeps this object alive until we're closed.
 
         // Used for blanking out password in trace.
         internal int _tracePasswordOffset = 0;
@@ -112,11 +112,7 @@ internal int DecrementPendingCallbacks(bool release)
             int remaining = Interlocked.Decrement(ref _pendingCallbacks);
             SqlClientEventSource.Log.TryAdvancedTraceEvent("<sc.TdsParserStateObject.DecrementPendingCallbacks|ADV> {0}, after decrementing _pendingCallbacks: {1}", ObjectID, _pendingCallbacks);
 
-            if ((0 == remaining || release) && _gcHandle.IsAllocated)
-            {
-                SqlClientEventSource.Log.TryAdvancedTraceEvent("<sc.TdsParserStateObject.DecrementPendingCallbacks|ADV> {0}, FREEING HANDLE!", ObjectID);
-                _gcHandle.Free();
-            }
+            FreeGcHandle(remaining, release);
 
             // NOTE: TdsParserSessionPool may call DecrementPendingCallbacks on a TdsParserStateObject which is already disposed
             // This is not dangerous (since the stateObj is no longer in use), but we need to add a workaround in the assert for it

src/Microsoft.Data.SqlClient/netfx/src/Microsoft/Data/SqlClient/TdsParserStateObjectNative.cs

@@ -7,6 +7,8 @@
 using System.Diagnostics;
 using System.Net;
 using System.Runtime.CompilerServices;
+using System.Runtime.ConstrainedExecution;
+using System.Runtime.InteropServices;
 using System.Threading.Tasks;
 using Interop.Windows.Sni;
 using Microsoft.Data.Common;
@@ -186,6 +188,16 @@ protected override void RemovePacketFromPendingList(PacketHandle ptr)
             }
         }
 
+        [ReliabilityContract(Consistency.WillNotCorruptState, Cer.Success)]
+        protected override void FreeGcHandle(int remaining, bool release)
+        {
+            if ((0 == remaining || release) && _gcHandle.IsAllocated)
+            {
+                SqlClientEventSource.Log.TryAdvancedTraceEvent("<sc.TdsParserStateObject.DecrementPendingCallbacks|ADV> {0}, FREEING HANDLE!", ObjectID);
+                _gcHandle.Free();
+            }
+        }
+
         internal override bool IsFailedHandle() => _sessionHandle.Status != TdsEnums.SNI_SUCCESS;
 
         internal override bool IsPacketEmpty(PacketHandle readPacket)

src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/TdsParserStateObject.cs

@@ -514,6 +514,8 @@ internal abstract void CreatePhysicalSNIHandle(
 
         protected abstract bool CheckPacket(PacketHandle packet, TaskCompletionSource<object> source);
 
+        protected abstract void FreeGcHandle(int remaining, bool release);
+
         internal abstract bool IsFailedHandle();
 
         internal abstract bool IsPacketEmpty(PacketHandle readPacket);