Undo buff rental in netfx to simplify 6.0 diff.

dotnet · cheenamalhotra · Aug 14, 2025 · Aug 5, 2025 · Aug 5, 2025 · Aug 5, 2025
commit a4ac40a5f628dd334bf2f3b8b971a6773e79a833
@@ -6220,35 +6220,19 @@ private TdsOperationStatus TryReadSqlStringValue(SqlBuffer value, byte type, int
                         if (isPlp)
                         {
                             char[] cc = null;
-                            bool buffIsRented = false;
-                            result = TryReadPlpUnicodeChars(ref cc, 0, length >> 1, stateObj, out length, supportRentedBuff: true, rentedBuff: ref buffIsRented);
+                            result = TryReadPlpUnicodeChars(ref cc, 0, length >> 1, stateObj, out length);
 
-                            if (result == TdsOperationStatus.Done)
+                            if (result != TdsOperationStatus.Done)
                             {
-                                if (length > 0)
-                                {
-                                    s = new string(cc, 0, length);
-                                }
-                                else
-                                {
-                                    s = string.Empty;
-                                }
+                                return result;
                             }
-
-                            if (buffIsRented)
+                            if (length > 0)
                             {
-                                // do not use clearArray:true on the rented array because it can be massively larger
-                                // than the space we've used and we would incur performance clearing memory that
-                                // we haven't used and can't leak out information.
-                                // clear only the length that we know we have used.
-                                cc.AsSpan(0, length).Clear();
-                                ArrayPool<char>.Shared.Return(cc, clearArray: false);
-                                cc = null;
+                                s = new string(cc, 0, length);
                             }
-
-                            if (result != TdsOperationStatus.Done)
+                            else
                             {
-                                return result;
+                                s = string.Empty;
                             }
                         }
                         else
@@ -13270,13 +13254,12 @@ internal TdsOperationStatus TryReadPlpUnicodeChars(
             int offst,
             int len,
             TdsParserStateObject stateObj,
-            out int totalCharsRead,
-            bool supportRentedBuff,
-            ref bool rentedBuff)
+            out int totalCharsRead)
         {
             int charsRead = 0;
             int charsLeft = 0;
             char[] newbuf;
+            TdsOperationStatus result;
 
             if (stateObj._longlen == 0)
             {
@@ -13285,29 +13268,18 @@ internal TdsOperationStatus TryReadPlpUnicodeChars(
                 return TdsOperationStatus.Done;       // No data
             }
 
-            Debug.Assert((ulong)stateObj._longlen != TdsEnums.SQL_PLP_NULL, "Out of sync plp read request");
+            Debug.Assert(((ulong)stateObj._longlen != TdsEnums.SQL_PLP_NULL),
+                    "Out of sync plp read request");
 
             Debug.Assert((buff == null && offst == 0) || (buff.Length >= offst + len), "Invalid length sent to ReadPlpUnicodeChars()!");
             charsLeft = len;
 
-            // If total length is known up front, the length isn't specified as unknown 
-            // and the caller doesn't pass int.max/2 indicating that it doesn't know the length
-            // allocate the whole buffer in one shot instead of realloc'ing and copying over each time
-            if (buff == null && stateObj._longlen != TdsEnums.SQL_PLP_UNKNOWNLEN && len < (int.MaxValue >> 1))
+            // If total length is known up front, allocate the whole buffer in one shot instead of realloc'ing and copying over each time
+            if (buff == null && stateObj._longlen != TdsEnums.SQL_PLP_UNKNOWNLEN)
             {
-                if (supportRentedBuff && len < 1073741824) // 1 Gib
-                {
-                    buff = ArrayPool<char>.Shared.Rent((int)Math.Min((int)stateObj._longlen, len));
-                    rentedBuff = true;
-                }
-                else
-                {
-                    buff = new char[(int)Math.Min((int)stateObj._longlen, len)];
-                    rentedBuff = false;
-                }
+                buff = new char[(int)Math.Min((int)stateObj._longlen, len)];
             }
 
-            TdsOperationStatus result;
             if (stateObj._longlenleft == 0)
             {
                 result = stateObj.TryReadPlpLength(false, out _);
@@ -13329,26 +13301,11 @@ internal TdsOperationStatus TryReadPlpUnicodeChars(
                 charsRead = (int)Math.Min((stateObj._longlenleft + 1) >> 1, (ulong)charsLeft);
                 if ((buff == null) || (buff.Length < (offst + charsRead)))
                 {
-                    bool returnRentedBufferAfterCopy = rentedBuff;
-                    if (supportRentedBuff && (offst + charsRead) < 1073741824) // 1 Gib
-                    {
-                        newbuf = ArrayPool<char>.Shared.Rent(offst + charsRead);
-                        rentedBuff = true;
-                    }
-                    else
-                    {
-                        newbuf = new char[offst + charsRead];
-                        rentedBuff = false;
-                    }
-
+                    // Grow the array
+                    newbuf = new char[offst + charsRead];
                     if (buff != null)
                     {
                         Buffer.BlockCopy(buff, 0, newbuf, 0, offst * 2);
-                        if (returnRentedBufferAfterCopy)
-                        {
-                            buff.AsSpan(0, offst).Clear();
-                            ArrayPool<char>.Shared.Return(buff, clearArray: false);
-                        }
                     }
                     buff = newbuf;
                 }