[6.1] Revert partial packet fixup and replay improvements (#3556)

* Revert 1af7327

* Revert "Fix TryReadPlpBytes throws ArgumentException (#3470) (#3474)"

This reverts commit 0a55896.

* Revert 44762d9

* Revert "Improve async string perf and fix reading chars with initial offset. (#3377)"

This reverts commit 05df554.

* Revert "Refine handling of moving between replay and continue states (#3337)"

This reverts commit 265f522.

* Revert "Fix SqlCached buffer async read with continue edge case. (#3329)"

This reverts commit c3857b1.

* Revert "Add `async` snapshot continue capability for multipacket fields (#3161)"

This reverts commit 33364e7.

* Revert "Add partial packet detection and fixup (#2714)"

This reverts commit 8d5e4f2.

* Remove methods previously moved to common file.

* Supply byte buffer to vector read.

* Minor compilation fixes that were missed in the reverts.

* Remove partial packet context switch helpers.

* Remove accidental duplication of SqlDataReader

* Revert len change

* Undo buff rental in netfx to simplify 6.0 diff.

* Fix missed rented buff code.

---------

Co-authored-by: Cheena Malhotra <cmalhotra@microsoft.com>

Author: mdaigle

src/Microsoft.Data.SqlClient/netcore/src/Microsoft.Data.SqlClient.csproj

@@ -354,9 +354,6 @@
     <Compile Include="$(CommonSourceRoot)Microsoft\Data\SqlClient\OnChangedEventHandler.cs">
       <Link>Microsoft\Data\SqlClient\OnChangedEventHandler.cs</Link>
     </Compile>
-    <Compile Include="$(CommonSourceRoot)Microsoft\Data\SqlClient\Packet.cs">
-      <Link>Microsoft\Data\SqlClient\Packet.cs</Link>
-    </Compile>
     <Compile Include="$(CommonSourceRoot)Microsoft\Data\SqlClient\ParameterPeekAheadValue.cs">
       <Link>Microsoft\Data\SqlClient\ParameterPeekAheadValue.cs</Link>
     </Compile>
@@ -762,9 +759,6 @@
     <Compile Include="$(CommonSourceRoot)Microsoft\Data\SqlClient\TdsParserStateObject.cs">
       <Link>Microsoft\Data\SqlClient\TdsParserStateObject.cs</Link>
     </Compile>
-    <Compile Include="$(CommonSourceRoot)Microsoft\Data\SqlClient\TdsParserStateObject.Multiplexer.cs">
-      <Link>Microsoft\Data\SqlClient\TdsParserStateObject.Multiplexer.cs</Link>
-    </Compile>
     <Compile Include="$(CommonSourceRoot)Microsoft\Data\SqlClient\TdsParserStaticMethods.cs">
       <Link>Microsoft\Data\SqlClient\TdsParserStaticMethods.cs</Link>
     </Compile>

src/Microsoft.Data.SqlClient/netcore/src/Microsoft/Data/SqlClient/TdsParser.Windows.cs

@@ -26,10 +26,6 @@ internal void PostReadAsyncForMars()
 
             _pMarsPhysicalConObj.IncrementPendingCallbacks();
             SessionHandle handle = _pMarsPhysicalConObj.SessionHandle;
-            // we do not need to consider partial packets when making this read because we
-            // expect this read to pend. a partial packet should not exist at setup of the
-            // parser
-            Debug.Assert(_physicalStateObj.PartialPacket==null);
             temp = _pMarsPhysicalConObj.ReadAsync(handle, out error);
 
             Debug.Assert(temp.Type == PacketHandle.NativePointerType, "unexpected packet type when requiring NativePointer");

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

@@ -167,22 +167,14 @@ private void ReadSniError(TdsParserStateObject stateObj, uint error)
                             stateObj.SendAttention(mustTakeWriteLock: true);
 
                             PacketHandle syncReadPacket = default;
-                            bool readFromNetwork = true;
                             RuntimeHelpers.PrepareConstrainedRegions();
                             bool shouldDecrement = false;
                             try
                             {
                                 Interlocked.Increment(ref _readingCount);
                                 shouldDecrement = true;
-                                readFromNetwork = !PartialPacketContainsCompletePacket();
-                                if (readFromNetwork)
-                                {
-                                    syncReadPacket = ReadSyncOverAsync(stateObj.GetTimeoutRemaining(), out error);
-                                }
-                                else
-                                {
-                                    error = TdsEnums.SNI_SUCCESS;
-                                }
+
+                                syncReadPacket = ReadSyncOverAsync(stateObj.GetTimeoutRemaining(), out error);
 
                                 Interlocked.Decrement(ref _readingCount);
                                 shouldDecrement = false;
@@ -195,7 +187,7 @@ private void ReadSniError(TdsParserStateObject stateObj, uint error)
                                 }
                                 else
                                 {
-                                    Debug.Assert(!readFromNetwork || !IsValidPacket(syncReadPacket), "unexpected syncReadPacket without corresponding SNIPacketRelease");
+                                    Debug.Assert(!IsValidPacket(syncReadPacket), "unexpected syncReadPacket without corresponding SNIPacketRelease");
                                     fail = true; // Subsequent read failed, time to give up.
                                 }
                             }
@@ -206,7 +198,7 @@ private void ReadSniError(TdsParserStateObject stateObj, uint error)
                                     Interlocked.Decrement(ref _readingCount);
                                 }
 
-                                if (readFromNetwork && !IsPacketEmpty(syncReadPacket))
+                                if (!IsPacketEmpty(syncReadPacket))
                                 {
                                     // Be sure to release packet, otherwise it will be leaked by native.
                                     ReleasePacket(syncReadPacket);
@@ -247,9 +239,60 @@ private void ReadSniError(TdsParserStateObject stateObj, uint error)
             AssertValidState();
         }
 
-        private uint GetSniPacket(PacketHandle packet, ref uint dataSize)
+        public void ProcessSniPacket(PacketHandle packet, uint error)
         {
-            return SniPacketGetData(packet, _inBuff, ref dataSize);
+            if (error != 0)
+            {
+                if ((_parser.State == TdsParserState.Closed) || (_parser.State == TdsParserState.Broken))
+                {
+                    // Do nothing with callback if closed or broken and error not 0 - callback can occur
+                    // after connection has been closed.  PROBLEM IN NETLIB - DESIGN FLAW.
+                    return;
+                }
+
+                AddError(_parser.ProcessSNIError(this));
+                AssertValidState();
+            }
+            else
+            {
+                uint dataSize = 0;
+
+                uint getDataError = SniPacketGetData(packet, _inBuff, ref dataSize);
+
+                if (getDataError == TdsEnums.SNI_SUCCESS)
+                {
+                    if (_inBuff.Length < dataSize)
+                    {
+                        Debug.Assert(true, "Unexpected dataSize on Read");
+                        throw SQL.InvalidInternalPacketSize(StringsHelper.GetString(Strings.SqlMisc_InvalidArraySizeMessage));
+                    }
+
+                    _lastSuccessfulIOTimer._value = DateTime.UtcNow.Ticks;
+                    _inBytesRead = (int)dataSize;
+                    _inBytesUsed = 0;
+
+                    if (_snapshot != null)
+                    {
+                        _snapshot.AppendPacketData(_inBuff, _inBytesRead);
+                        if (_snapshotReplay)
+                        {
+                            _snapshot.MoveNext();
+#if DEBUG
+                            _snapshot.AssertCurrent();
+#endif
+                        }
+                    }
+
+                    SniReadStatisticsAndTracing();
+                    SqlClientEventSource.Log.TryAdvancedTraceBinEvent("TdsParser.ReadNetworkPacketAsyncCallback | INFO | ADV | State Object Id {0}, Packet read. In Buffer: {1}, In Bytes Read: {2}", ObjectID, _inBuff, _inBytesRead);
+
+                    AssertValidState();
+                }
+                else
+                {
+                    throw SQL.ParsingError(ParsingErrorState.ProcessSniPacketFailed);
+                }
+            }
         }
 
         private void SetBufferSecureStrings()
@@ -321,7 +364,7 @@ public void ReadAsyncCallback(IntPtr key, PacketHandle packet, uint error)
             bool processFinallyBlock = true;
             try
             {
-                Debug.Assert((packet.Type == 0 && PartialPacketContainsCompletePacket()) || (CheckPacket(packet, source) && source != null), "AsyncResult null on callback");
+                Debug.Assert(CheckPacket(packet, source) && source != null, "AsyncResult null on callback");
 
                 if (_parser.MARSOn)
                 {

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

@@ -459,9 +459,6 @@
     <Compile Include="$(CommonSourceRoot)Microsoft\Data\SqlClient\OnChangedEventHandler.cs">
       <Link>Microsoft\Data\SqlClient\OnChangedEventHandler.cs</Link>
     </Compile>
-    <Compile Include="$(CommonSourceRoot)Microsoft\Data\SqlClient\Packet.cs">
-      <Link>Microsoft\Data\SqlClient\Packet.cs</Link>
-    </Compile>
     <Compile Include="$(CommonSourceRoot)Microsoft\Data\SqlClient\PacketHandle.Windows.cs">
       <Link>Microsoft\Data\SqlClient\PacketHandle.Windows.cs</Link>
     </Compile>
@@ -855,9 +852,6 @@
     <Compile Include="$(CommonSourceRoot)Microsoft\Data\SqlClient\TdsParserStateObject.cs">
       <Link>Microsoft\Data\SqlClient\TdsParserStateObject.cs</Link>
     </Compile>
-    <Compile Include="$(CommonSourceRoot)Microsoft\Data\SqlClient\TdsParserStateObject.Multiplexer.cs">
-      <Link>Microsoft\Data\SqlClient\TdsParserStateObject.Multiplexer.cs</Link>
-    </Compile>
     <Compile Include="$(CommonSourceRoot)Microsoft\Data\SqlClient\TdsParserStateObjectFactory.Windows.cs">
       <Link>Microsoft\Data\SqlClient\TdsParserStateObjectFactory.Windows.cs</Link>
     </Compile>