System.Data.SqlClient.TdsParser.WriteBulkCopyValue C# (CSharp) Method

        internal Task WriteBulkCopyValue(object value, SqlMetaDataPriv metadata, TdsParserStateObject stateObj, bool isSqlType, bool isDataFeed, bool isNull)
        {
            Debug.Assert(!isSqlType || value is INullable, "isSqlType is true, but value can not be type cast to an INullable");
            Debug.Assert(!isDataFeed ^ value is DataFeed, "Incorrect value for isDataFeed");

            Encoding saveEncoding = _defaultEncoding;
            SqlCollation saveCollation = _defaultCollation;
            int saveCodePage = _defaultCodePage;
            int saveLCID = _defaultLCID;
            Task resultTask = null;
            Task internalWriteTask = null;

            if (!(State == TdsParserState.OpenNotLoggedIn || State == TdsParserState.OpenLoggedIn))
            {
                throw ADP.ClosedConnectionError();
            }
            try
            {
                if (metadata.encoding != null)
                {
                    _defaultEncoding = metadata.encoding;
                }
                if (metadata.collation != null)
                {
                    _defaultCollation = metadata.collation;
                    _defaultLCID = _defaultCollation.LCID;
                }
                _defaultCodePage = metadata.codePage;

                MetaType metatype = metadata.metaType;
                int ccb = 0;
                int ccbStringBytes = 0;

                if (isNull)
                {
                    // For UDT, remember we treat as binary even though it is a PLP
                    if (metatype.IsPlp && (metatype.NullableType != TdsEnums.SQLUDT || metatype.IsLong))
                    {
                        WriteLong(unchecked((long)TdsEnums.SQL_PLP_NULL), stateObj);
                    }
                    else if (!metatype.IsFixed && !metatype.IsLong && !metatype.IsVarTime)
                    {
                        WriteShort(TdsEnums.VARNULL, stateObj);
                    }
                    else
                    {
                        stateObj.WriteByte(TdsEnums.FIXEDNULL);
                    }
                    return resultTask;
                }

                if (!isDataFeed)
                {
                    switch (metatype.NullableType)
                    {
                        case TdsEnums.SQLBIGBINARY:
                        case TdsEnums.SQLBIGVARBINARY:
                        case TdsEnums.SQLIMAGE:
                        case TdsEnums.SQLUDT:
                            ccb = (isSqlType) ? ((SqlBinary)value).Length : ((byte[])value).Length;
                            break;
                        case TdsEnums.SQLUNIQUEID:
                            ccb = GUID_SIZE;   // that's a constant for guid
                            break;
                        case TdsEnums.SQLBIGCHAR:
                        case TdsEnums.SQLBIGVARCHAR:
                        case TdsEnums.SQLTEXT:
                            if (null == _defaultEncoding)
                            {
                                ThrowUnsupportedCollationEncountered(null); // stateObject only when reading
                            }

                            string stringValue = null;
                            if (isSqlType)
                            {
                                stringValue = ((SqlString)value).Value;
                            }
                            else
                            {
                                stringValue = (string)value;
                            }

                            ccb = stringValue.Length;
                            ccbStringBytes = _defaultEncoding.GetByteCount(stringValue);
                            break;
                        case TdsEnums.SQLNCHAR:
                        case TdsEnums.SQLNVARCHAR:
                        case TdsEnums.SQLNTEXT:
                            ccb = ((isSqlType) ? ((SqlString)value).Value.Length : ((string)value).Length) * 2;
                            break;
                        case TdsEnums.SQLXMLTYPE:
                            // Value here could be string or XmlReader
                            if (value is XmlReader)
                            {
                                value = MetaType.GetStringFromXml((XmlReader)value);
                            }
                            ccb = ((isSqlType) ? ((SqlString)value).Value.Length : ((string)value).Length) * 2;
                            break;

                        default:
                            ccb = metadata.length;
                            break;
                    }
                }
                else
                {
                    Debug.Assert(metatype.IsLong &&
                        ((metatype.SqlDbType == SqlDbType.VarBinary && value is StreamDataFeed) ||
                         ((metatype.SqlDbType == SqlDbType.VarChar || metatype.SqlDbType == SqlDbType.NVarChar) && value is TextDataFeed) ||
                         (metatype.SqlDbType == SqlDbType.Xml && value is XmlDataFeed)),
                   "Stream data feed should only be assigned to VarBinary(max), Text data feed should only be assigned to [N]VarChar(max), Xml data feed should only be assigned to XML(max)");
                }


                // Expected the text length in data stream for bulk copy of text, ntext, or image data.
                //
                if (metatype.IsLong)
                {
                    switch (metatype.SqlDbType)
                    {
                        case SqlDbType.Text:
                        case SqlDbType.NText:
                        case SqlDbType.Image:
                            stateObj.WriteByteArray(s_longDataHeader, s_longDataHeader.Length, 0);
                            WriteTokenLength(metadata.tdsType, ccbStringBytes == 0 ? ccb : ccbStringBytes, stateObj);
                            break;

                        case SqlDbType.VarChar:
                        case SqlDbType.NVarChar:
                        case SqlDbType.VarBinary:
                        case SqlDbType.Xml:
                        case SqlDbType.Udt:
                            // plp data
                            WriteUnsignedLong(TdsEnums.SQL_PLP_UNKNOWNLEN, stateObj);
                            break;
                    }
                }
                else
                {
                    WriteTokenLength(metadata.tdsType, ccbStringBytes == 0 ? ccb : ccbStringBytes, stateObj);
                }

                if (isSqlType)
                {
                    internalWriteTask = WriteSqlValue(value, metatype, ccb, ccbStringBytes, 0, stateObj);
                }
                else if (metatype.SqlDbType != SqlDbType.Udt || metatype.IsLong)
                {
                    internalWriteTask = WriteValue(value, metatype, metadata.scale, ccb, ccbStringBytes, 0, stateObj, metadata.length, isDataFeed);
                    if ((internalWriteTask == null) && (_asyncWrite))
                    {
                        internalWriteTask = stateObj.WaitForAccumulatedWrites();
                    }
                    Debug.Assert(_asyncWrite || stateObj.WaitForAccumulatedWrites() == null, "Should not have accumulated writes when writing sync");
                }
                else
                {
                    WriteShort(ccb, stateObj);
                    internalWriteTask = stateObj.WriteByteArray((byte[])value, ccb, 0);
                }

#if DEBUG
                //In DEBUG mode, when SetAlwaysTaskOnWrite is true, we create a task. Allows us to verify async execution paths.
                if (_asyncWrite && internalWriteTask == null && SqlBulkCopy.SetAlwaysTaskOnWrite == true)
                {
                    internalWriteTask = Task.FromResult<object>(null);
                }
#endif
                if (internalWriteTask != null)
                { //i.e. the write was async.
                    resultTask = WriteBulkCopyValueSetupContinuation(internalWriteTask, saveEncoding, saveCollation, saveCodePage, saveLCID);
                }
            }
            finally
            {
                if (internalWriteTask == null)
                {
                    _defaultEncoding = saveEncoding;
                    _defaultCollation = saveCollation;
                    _defaultCodePage = saveCodePage;
                    _defaultLCID = saveLCID;
                }
            }
            return resultTask;
        }