Exemplo n.º 1
0
        //
        // Read in a SQLVariant
        //
        // SQLVariant looks like:
        // struct
        // {
        //      BYTE TypeTag
        //      BYTE cbPropBytes
        //      BYTE[] Properties
        //      BYTE[] DataVal
        // }
        internal bool TryReadSqlVariant(SqlBuffer value, int lenTotal, TdsParserStateObject stateObj)
        {
            // get the SQLVariant type
            byte type;
            if (!stateObj.TryReadByte(out type))
            {
                return false;
            }
            ushort lenMax = 0; // maximum lenData of value inside variant

            // read cbPropBytes
            byte cbPropsActual;
            if (!stateObj.TryReadByte(out cbPropsActual))
            {
                return false;
            }
            MetaType mt = MetaType.GetSqlDataType(type, 0 /*no user datatype*/, 0 /* no lenData, non-nullable type */);
            byte cbPropsExpected = mt.PropBytes;

            int lenConsumed = TdsEnums.SQLVARIANT_SIZE + cbPropsActual; // type, count of propBytes, and actual propBytes
            int lenData = lenTotal - lenConsumed; // length of actual data

            // read known properties and skip unknown properties
            Debug.Assert(cbPropsActual >= cbPropsExpected, "cbPropsActual is less that cbPropsExpected!");

            //
            // now read the value
            //
            switch (type)
            {
                case TdsEnums.SQLBIT:
                case TdsEnums.SQLINT1:
                case TdsEnums.SQLINT2:
                case TdsEnums.SQLINT4:
                case TdsEnums.SQLINT8:
                case TdsEnums.SQLFLT4:
                case TdsEnums.SQLFLT8:
                case TdsEnums.SQLMONEY:
                case TdsEnums.SQLMONEY4:
                case TdsEnums.SQLDATETIME:
                case TdsEnums.SQLDATETIM4:
                case TdsEnums.SQLUNIQUEID:
                    if (!TryReadSqlValueInternal(value, type, lenData, stateObj))
                    {
                        return false;
                    }
                    break;

                case TdsEnums.SQLDECIMALN:
                case TdsEnums.SQLNUMERICN:
                    {
                        Debug.Assert(cbPropsExpected == 2, "SqlVariant: invalid PropBytes for decimal/numeric type!");

                        byte precision;
                        if (!stateObj.TryReadByte(out precision))
                        {
                            return false;
                        }
                        byte scale;
                        if (!stateObj.TryReadByte(out scale))
                        {
                            return false;
                        }

                        // skip over unknown properties
                        if (cbPropsActual > cbPropsExpected)
                        {
                            if (!stateObj.TrySkipBytes(cbPropsActual - cbPropsExpected))
                            {
                                return false;
                            }
                        }

                        if (!TryReadSqlDecimal(value, TdsEnums.MAX_NUMERIC_LEN, precision, scale, stateObj))
                        {
                            return false;
                        }
                        break;
                    }

                case TdsEnums.SQLBIGBINARY:
                case TdsEnums.SQLBIGVARBINARY:
                    //Debug.Assert(TdsEnums.VARNULL == lenData, "SqlVariant: data length for Binary indicates null?");
                    Debug.Assert(cbPropsExpected == 2, "SqlVariant: invalid PropBytes for binary type!");

                    if (!stateObj.TryReadUInt16(out lenMax))
                    {
                        return false;
                    }
                    Debug.Assert(lenMax != TdsEnums.SQL_USHORTVARMAXLEN, "bigvarbinary(max) in a sqlvariant");

                    // skip over unknown properties
                    if (cbPropsActual > cbPropsExpected)
                    {
                        if (!stateObj.TrySkipBytes(cbPropsActual - cbPropsExpected))
                        {
                            return false;
                        }
                    }

                    goto case TdsEnums.SQLBIT;

                case TdsEnums.SQLBIGCHAR:
                case TdsEnums.SQLBIGVARCHAR:
                case TdsEnums.SQLNCHAR:
                case TdsEnums.SQLNVARCHAR:
                    {
                        Debug.Assert(cbPropsExpected == 7, "SqlVariant: invalid PropBytes for character type!");

                        SqlCollation collation;
                        if (!TryProcessCollation(stateObj, out collation))
                        {
                            return false;
                        }

                        if (!stateObj.TryReadUInt16(out lenMax))
                        {
                            return false;
                        }
                        Debug.Assert(lenMax != TdsEnums.SQL_USHORTVARMAXLEN, "bigvarchar(max) or nvarchar(max) in a sqlvariant");

                        // skip over unknown properties
                        if (cbPropsActual > cbPropsExpected)
                        {
                            if (!stateObj.TrySkipBytes(cbPropsActual - cbPropsExpected))
                            {
                                return false;
                            }
                        }

                        Encoding encoding = Encoding.GetEncoding(GetCodePage(collation, stateObj));
                        if (!TryReadSqlStringValue(value, type, lenData, encoding, false, stateObj))
                        {
                            return false;
                        }
                        break;
                    }
                case TdsEnums.SQLDATE:
                    if (!TryReadSqlDateTime(value, type, lenData, 0, stateObj))
                    {
                        return false;
                    }
                    break;

                case TdsEnums.SQLTIME:
                case TdsEnums.SQLDATETIME2:
                case TdsEnums.SQLDATETIMEOFFSET:
                    {
                        Debug.Assert(cbPropsExpected == 1, "SqlVariant: invalid PropBytes for time/datetime2/datetimeoffset type!");

                        byte scale;
                        if (!stateObj.TryReadByte(out scale))
                        {
                            return false;
                        }

                        // skip over unknown properties
                        if (cbPropsActual > cbPropsExpected)
                        {
                            if (!stateObj.TrySkipBytes(cbPropsActual - cbPropsExpected))
                            {
                                return false;
                            }
                        }

                        if (!TryReadSqlDateTime(value, type, lenData, scale, stateObj))
                        {
                            return false;
                        }
                        break;
                    }

                default:
                    Debug.Assert(false, "Unknown tds type in SqlVariant!" + type.ToString(CultureInfo.InvariantCulture));
                    break;
            } // switch

            return true;
        }
Exemplo n.º 2
0
        internal bool TrySkipPlpValue(ulong cb, TdsParserStateObject stateObj, out ulong totalBytesSkipped)
        {
            // Read and skip cb bytes or until  ReadPlpLength returns 0.
            int bytesSkipped;
            totalBytesSkipped = 0;

            if (stateObj._longlenleft == 0)
            {
                ulong ignored;
                if (!stateObj.TryReadPlpLength(false, out ignored))
                {
                    return false;
                }
            }

            while ((totalBytesSkipped < cb) &&
                    (stateObj._longlenleft > 0))
            {
                if (stateObj._longlenleft > Int32.MaxValue)
                    bytesSkipped = Int32.MaxValue;
                else
                    bytesSkipped = (int)stateObj._longlenleft;
                bytesSkipped = ((cb - totalBytesSkipped) < (ulong)bytesSkipped) ? (int)(cb - totalBytesSkipped) : bytesSkipped;

                if (!stateObj.TrySkipBytes(bytesSkipped))
                {
                    return false;
                }
                stateObj._longlenleft -= (ulong)bytesSkipped;
                totalBytesSkipped += (ulong)bytesSkipped;

                if (stateObj._longlenleft == 0)
                {
                    ulong ignored;
                    if (!stateObj.TryReadPlpLength(false, out ignored))
                    {
                        return false;
                    }
                }
            }

            return true;
        }
Exemplo n.º 3
0
        private bool TryProcessColumnHeaderNoNBC(SqlMetaDataPriv col, TdsParserStateObject stateObj, out bool isNull, out ulong length)
        {
            if (col.metaType.IsLong && !col.metaType.IsPlp)
            {
                //
                // we don't care about TextPtrs, simply go after the data after it
                //
                byte textPtrLen;
                if (!stateObj.TryReadByte(out textPtrLen))
                {
                    isNull = false;
                    length = 0;
                    return false;
                }

                if (0 != textPtrLen)
                {
                    // read past text pointer
                    if (!stateObj.TrySkipBytes(textPtrLen))
                    {
                        isNull = false;
                        length = 0;
                        return false;
                    }

                    // read past timestamp
                    if (!stateObj.TrySkipBytes(TdsEnums.TEXT_TIME_STAMP_LEN))
                    {
                        isNull = false;
                        length = 0;
                        return false;
                    }

                    isNull = false;
                    return TryGetDataLength(col, stateObj, out length);
                }
                else
                {
                    isNull = true;
                    length = 0;
                    return true;
                }
            }
            else
            {
                // non-blob columns
                ulong longlen;
                if (!TryGetDataLength(col, stateObj, out longlen))
                {
                    isNull = false;
                    length = 0;
                    return false;
                }
                isNull = IsNull(col.metaType, longlen);
                length = (isNull ? 0 : longlen);
                return true;
            }
        }
Exemplo n.º 4
0
        /// <summary>
        /// This method skips bytes of a single column value from the media. It supports NBCROW and handles all types of values, including PLP and long
        /// </summary>
        internal bool TrySkipValue(SqlMetaDataPriv md, int columnOrdinal, TdsParserStateObject stateObj)
        {
            if (stateObj.IsNullCompressionBitSet(columnOrdinal))
            {
                return true;
            }

            if (md.metaType.IsPlp)
            {
                ulong ignored;
                if (!TrySkipPlpValue(UInt64.MaxValue, stateObj, out ignored))
                {
                    return false;
                }
            }
            else if (md.metaType.IsLong)
            {
                Debug.Assert(!md.metaType.IsPlp, "Plp types must be handled using SkipPlpValue");

                byte textPtrLen;
                if (!stateObj.TryReadByte(out textPtrLen))
                {
                    return false;
                }

                if (0 != textPtrLen)
                {
                    if (!stateObj.TrySkipBytes(textPtrLen + TdsEnums.TEXT_TIME_STAMP_LEN))
                    {
                        return false;
                    }

                    int length;
                    if (!TryGetTokenLength(md.tdsType, stateObj, out length))
                    {
                        return false;
                    }
                    if (!stateObj.TrySkipBytes(length))
                    {
                        return false;
                    }
                }
            }
            else
            {
                int length;
                if (!TryGetTokenLength(md.tdsType, stateObj, out length))
                {
                    return false;
                }

                // if false, no value to skip - it's null
                if (!IsNull(md.metaType, (ulong)length))
                {
                    if (!stateObj.TrySkipBytes(length))
                    {
                        return false;
                    }
                }
            }

            return true;
        }
Exemplo n.º 5
0
        internal bool TryProcessAltMetaData(int cColumns, TdsParserStateObject stateObj, out _SqlMetaDataSet metaData)
        {
            Debug.Assert(cColumns > 0, "should have at least 1 column in altMetaData!");

            metaData = null;

            _SqlMetaDataSet altMetaDataSet = new _SqlMetaDataSet(cColumns);
            int[] indexMap = new int[cColumns];

            if (!stateObj.TryReadUInt16(out altMetaDataSet.id))
            {
                return false;
            }

            byte byCols;
            if (!stateObj.TryReadByte(out byCols))
            {
                return false;
            }

            while (byCols > 0)
            {
                if (!stateObj.TrySkipBytes(2))
                { // ignore ColNum ...
                    return false;
                }
                byCols--;
            }

            // pass 1, read the meta data off the wire
            for (int i = 0; i < cColumns; i++)
            {
                // internal meta data class
                _SqlMetaData col = altMetaDataSet[i];

                byte op;
                if (!stateObj.TryReadByte(out op))
                {
                    return false;
                }
                ushort operand;
                if (!stateObj.TryReadUInt16(out operand))
                {
                    return false;
                }

                if (!TryCommonProcessMetaData(stateObj, col))
                {
                    return false;
                }

                indexMap[i] = i;
            }

            altMetaDataSet.indexMap = indexMap;
            altMetaDataSet.visibleColumns = cColumns;

            metaData = altMetaDataSet;
            return true;
        }
Exemplo n.º 6
0
        // augments current metadata with table and key information
        private bool TryProcessColInfo(_SqlMetaDataSet columns, SqlDataReader reader, TdsParserStateObject stateObj, out _SqlMetaDataSet metaData)
        {
            Debug.Assert(columns != null && columns.Length > 0, "no metadata available!");

            metaData = null;

            for (int i = 0; i < columns.Length; i++)
            {
                _SqlMetaData col = columns[i];

                byte ignored;
                if (!stateObj.TryReadByte(out ignored))
                { // colnum, ignore
                    return false;
                }
                if (!stateObj.TryReadByte(out ignored))
                { // tablenum, ignore
                    return false;
                }

                // interpret status
                byte status;
                if (!stateObj.TryReadByte(out status))
                {
                    return false;
                }

                col.isKey = (TdsEnums.SQLKey == (status & TdsEnums.SQLKey));
                col.isHidden = (TdsEnums.SQLHidden == (status & TdsEnums.SQLHidden));

                // read off the base table name if it is different than the select list column name
                if (TdsEnums.SQLDifferentName == (status & TdsEnums.SQLDifferentName))
                {
                    byte len;
                    if (!stateObj.TryReadByte(out len))
                    {
                        return false;
                    }
                    if (!stateObj.TrySkipBytes(len * ADP.CharSize))
                    {
                        return false;
                    }
                }


                if (TdsEnums.SQLExpression == (status & TdsEnums.SQLExpression))
                {
                    col.updatability = 0;
                }
            }

            // set the metadata so that the stream knows some metadata info has changed
            metaData = columns;
            return true;
        }
Exemplo n.º 7
0
        private bool TryProcessLoginAck(TdsParserStateObject stateObj, out SqlLoginAck sqlLoginAck)
        {
            SqlLoginAck a = new SqlLoginAck();

            sqlLoginAck = null;

            // read past interface type and version
            if (!stateObj.TrySkipBytes(1))
            {
                return false;
            }

            byte[] b = new byte[TdsEnums.VERSION_SIZE];
            if (!stateObj.TryReadByteArray(b, 0, b.Length))
            {
                return false;
            }
            a.tdsVersion = (UInt32)((((((b[0] << 8) | b[1]) << 8) | b[2]) << 8) | b[3]); // bytes are in motorola order (high byte first)
            UInt32 majorMinor = a.tdsVersion & 0xff00ffff;
            UInt32 increment = (a.tdsVersion >> 16) & 0xff;

            // Server responds:
            // 0x07000000 -> Sphinx         // Notice server response format is different for bwd compat
            // 0x07010000 -> Shiloh RTM     // Notice server response format is different for bwd compat
            // 0x71000001 -> Shiloh SP1
            // 0x72xx0002 -> Yukon RTM
            // information provided by S. Ashwin

            switch (majorMinor)
            {
                case TdsEnums.YUKON_MAJOR << 24 | TdsEnums.YUKON_RTM_MINOR:     // Yukon
                    if (increment != TdsEnums.YUKON_INCREMENT) { throw SQL.InvalidTDSVersion(); }
                    break;
                case TdsEnums.KATMAI_MAJOR << 24 | TdsEnums.KATMAI_MINOR:
                    if (increment != TdsEnums.KATMAI_INCREMENT) { throw SQL.InvalidTDSVersion(); }
                    _isKatmai = true;
                    break;
                case TdsEnums.DENALI_MAJOR << 24 | TdsEnums.DENALI_MINOR:
                    if (increment != TdsEnums.DENALI_INCREMENT) { throw SQL.InvalidTDSVersion(); }
                    _isDenali = true;
                    break;
                default:
                    throw SQL.InvalidTDSVersion();
            }

            _isKatmai |= _isDenali;

            stateObj._outBytesUsed = stateObj._outputHeaderLen;
            byte len;
            if (!stateObj.TryReadByte(out len))
            {
                return false;
            }

            if (!stateObj.TrySkipBytes(len * ADP.CharSize))
            {
                return false;
            }
            if (!stateObj.TryReadByte(out a.majorVersion))
            {
                return false;
            }
            if (!stateObj.TryReadByte(out a.minorVersion))
            {
                return false;
            }
            byte buildNumHi, buildNumLo;
            if (!stateObj.TryReadByte(out buildNumHi))
            {
                return false;
            }
            if (!stateObj.TryReadByte(out buildNumLo))
            {
                return false;
            }

            a.buildNum = (short)((buildNumHi << 8) + buildNumLo);

            Debug.Assert(_state == TdsParserState.OpenNotLoggedIn, "ProcessLoginAck called with state not TdsParserState.OpenNotLoggedIn");
            _state = TdsParserState.OpenLoggedIn;

            {
                if (_fMARS)
                {
                    _resetConnectionEvent = new AutoResetEvent(true);
                }
            }

            // Fail if SSE UserInstance and we have not received this info.
            if (_connHandler.ConnectionOptions.UserInstance &&
                ADP.IsEmpty(_connHandler.InstanceName))
            {
                stateObj.AddError(new SqlError(0, 0, TdsEnums.FATAL_ERROR_CLASS, Server, SQLMessage.UserInstanceFailure(), "", 0));
                ThrowExceptionAndWarning(stateObj);
            }

            sqlLoginAck = a;
            return true;
        }
Exemplo n.º 8
0
        private bool TryProcessSessionState(TdsParserStateObject stateObj, int length, SessionData sdata)
        {
            if (length < 5)
            {
                throw SQL.ParsingError();
            }
            UInt32 seqNum;
            if (!stateObj.TryReadUInt32(out seqNum))
            {
                return false;
            }
            if (seqNum == UInt32.MaxValue)
            {
                _connHandler.DoNotPoolThisConnection();
            }
            byte status;
            if (!stateObj.TryReadByte(out status))
            {
                return false;
            }
            if (status > 1)
            {
                throw SQL.ParsingError();
            }
            bool recoverable = status != 0;
            length -= 5;
            while (length > 0)
            {
                byte stateId;
                if (!stateObj.TryReadByte(out stateId))
                {
                    return false;
                }
                int stateLen;
                byte stateLenByte;
                if (!stateObj.TryReadByte(out stateLenByte))
                {
                    return false;
                }
                if (stateLenByte < 0xFF)
                {
                    stateLen = stateLenByte;
                }
                else
                {
                    if (!stateObj.TryReadInt32(out stateLen))
                    {
                        return false;
                    }
                }
                byte[] buffer = null;
                lock (sdata._delta)
                {
                    if (sdata._delta[stateId] == null)
                    {
                        buffer = new byte[stateLen];
                        sdata._delta[stateId] = new SessionStateRecord { _version = seqNum, _dataLength = stateLen, _data = buffer, _recoverable = recoverable };
                        sdata._deltaDirty = true;
                        if (!recoverable)
                        {
                            checked { sdata._unrecoverableStatesCount++; }
                        }
                    }
                    else
                    {
                        if (sdata._delta[stateId]._version <= seqNum)
                        {
                            SessionStateRecord sv = sdata._delta[stateId];
                            sv._version = seqNum;
                            sv._dataLength = stateLen;
                            if (sv._recoverable != recoverable)
                            {
                                if (recoverable)
                                {
                                    Debug.Assert(sdata._unrecoverableStatesCount > 0, "Unrecoverable states count >0");
                                    sdata._unrecoverableStatesCount--;
                                }
                                else
                                {
                                    checked { sdata._unrecoverableStatesCount++; }
                                }
                                sv._recoverable = recoverable;
                            }
                            buffer = sv._data;
                            if (buffer.Length < stateLen)
                            {
                                buffer = new byte[stateLen];
                                sv._data = buffer;
                            }
                        }
                    }
                }
                if (buffer != null)
                {
                    if (!stateObj.TryReadByteArray(buffer, 0, stateLen))
                    {
                        return false;
                    }
                }
                else
                {
                    if (!stateObj.TrySkipBytes(stateLen))
                        return false;
                }

                if (stateLenByte < 0xFF)
                {
                    length -= 2 + stateLen;
                }
                else
                {
                    length -= 6 + stateLen;
                }
            }
            sdata.AssertUnrecoverableStateCountIsCorrect();

            return true;
        }
Exemplo n.º 9
0
        private bool TryProcessEnvChange(int tokenLength, TdsParserStateObject stateObj, out SqlEnvChange[] sqlEnvChange)
        {
            // There could be multiple environment change messages following this token.
            byte byteLength;
            int processedLength = 0;
            int nvalues = 0;
            SqlEnvChange[] envarray = new SqlEnvChange[3];  // Why is this hardcoded to 3?

            sqlEnvChange = null;

            while (tokenLength > processedLength)
            {
                if (nvalues >= envarray.Length)
                {
                    // This is a rare path. Most of the time we will have 1 or 2 envchange data streams.
                    SqlEnvChange[] newenvarray = new SqlEnvChange[envarray.Length + 3];

                    for (int ii = 0; ii < envarray.Length; ii++)
                        newenvarray[ii] = envarray[ii];

                    envarray = newenvarray;
                }

                SqlEnvChange env = new SqlEnvChange();

                if (!stateObj.TryReadByte(out env.type))
                {
                    return false;
                }

                envarray[nvalues] = env;
                nvalues++;

                switch (env.type)
                {
                    case TdsEnums.ENV_DATABASE:
                    case TdsEnums.ENV_LANG:
                        if (!TryReadTwoStringFields(env, stateObj))
                        {
                            return false;
                        }
                        break;

                    case TdsEnums.ENV_CHARSET:
                        // we copied this behavior directly from luxor - see charset envchange
                        // section from sqlctokn.c
                        if (!TryReadTwoStringFields(env, stateObj))
                        {
                            return false;
                        }
                        if (env.newValue == TdsEnums.DEFAULT_ENGLISH_CODE_PAGE_STRING)
                        {
                            _defaultCodePage = TdsEnums.DEFAULT_ENGLISH_CODE_PAGE_VALUE;
                            _defaultEncoding = System.Text.Encoding.GetEncoding(_defaultCodePage);
                        }
                        else
                        {
                            Debug.Assert(env.newValue.Length > TdsEnums.CHARSET_CODE_PAGE_OFFSET, "TdsParser.ProcessEnvChange(): charset value received with length <=10");

                            string stringCodePage = env.newValue.Substring(TdsEnums.CHARSET_CODE_PAGE_OFFSET);

                            _defaultCodePage = Int32.Parse(stringCodePage, NumberStyles.Integer, CultureInfo.InvariantCulture);
                            _defaultEncoding = System.Text.Encoding.GetEncoding(_defaultCodePage);
                        }

                        break;

                    case TdsEnums.ENV_PACKETSIZE:
                        // take care of packet size right here
                        Debug.Assert(stateObj._syncOverAsync, "Should not attempt pends in a synchronous call");
                        if (!TryReadTwoStringFields(env, stateObj))
                        {
                            // Changing packet size does not support retry, should not pend"
                            throw SQL.SynchronousCallMayNotPend();
                        }
                        // Only set on physical state object - this should only occur on LoginAck prior
                        // to MARS initialization!
                        Int32 packetSize = Int32.Parse(env.newValue, NumberStyles.Integer, CultureInfo.InvariantCulture);

                        if (_physicalStateObj.SetPacketSize(packetSize))
                        {
                            // If packet size changed, we need to release our SNIPackets since
                            // those are tied to packet size of connection.
                            _physicalStateObj.ClearAllWritePackets();

                            // Update SNI ConsumerInfo value to be resulting packet size
                            UInt32 unsignedPacketSize = (UInt32)packetSize;
                            UInt32 result = SNINativeMethodWrapper.SNISetInfo(_physicalStateObj.Handle, SNINativeMethodWrapper.QTypes.SNI_QUERY_CONN_BUFSIZE, ref unsignedPacketSize);

                            Debug.Assert(result == TdsEnums.SNI_SUCCESS, "Unexpected failure state upon calling SNISetInfo");
                        }

                        break;

                    case TdsEnums.ENV_LOCALEID:
                        if (!TryReadTwoStringFields(env, stateObj))
                        {
                            return false;
                        }
                        _defaultLCID = Int32.Parse(env.newValue, NumberStyles.Integer, CultureInfo.InvariantCulture);
                        break;

                    case TdsEnums.ENV_COMPFLAGS:
                        if (!TryReadTwoStringFields(env, stateObj))
                        {
                            return false;
                        }
                        break;

                    case TdsEnums.ENV_COLLATION:
                        Debug.Assert(env.newLength == 5 || env.newLength == 0, "Improper length in new collation!");
                        if (!stateObj.TryReadByte(out byteLength))
                        {
                            return false;
                        }
                        env.newLength = byteLength;
                        if (env.newLength == 5)
                        {
                            if (!TryProcessCollation(stateObj, out env.newCollation))
                            {
                                return false;
                            }

                            // give the parser the new collation values in case parameters don't specify one
                            _defaultCollation = env.newCollation;
                            int newCodePage = GetCodePage(env.newCollation, stateObj);
                            if (newCodePage != _defaultCodePage)
                            {
                                _defaultCodePage = newCodePage;
                                _defaultEncoding = System.Text.Encoding.GetEncoding(_defaultCodePage);
                            }
                            _defaultLCID = env.newCollation.LCID;
                        }

                        if (!stateObj.TryReadByte(out byteLength))
                        {
                            return false;
                        }
                        env.oldLength = byteLength;
                        Debug.Assert(env.oldLength == 5 || env.oldLength == 0, "Improper length in old collation!");
                        if (env.oldLength == 5)
                        {
                            if (!TryProcessCollation(stateObj, out env.oldCollation))
                            {
                                return false;
                            }
                        }

                        env.length = 3 + env.newLength + env.oldLength;
                        break;

                    case TdsEnums.ENV_BEGINTRAN:
                    case TdsEnums.ENV_COMMITTRAN:
                    case TdsEnums.ENV_ROLLBACKTRAN:

                        if (!stateObj.TryReadByte(out byteLength))
                        {
                            return false;
                        }
                        env.newLength = byteLength;
                        Debug.Assert(env.newLength == 0 || env.newLength == 8, "Improper length for new transaction id!");

                        if (env.newLength > 0)
                        {
                            if (!stateObj.TryReadInt64(out env.newLongValue))
                            {
                                return false;
                            }
                            Debug.Assert(env.newLongValue != SqlInternalTransaction.NullTransactionId, "New transaction id is null?"); // the server guarantees that zero is an invalid transaction id.
                        }
                        else
                        {
                            env.newLongValue = SqlInternalTransaction.NullTransactionId; // the server guarantees that zero is an invalid transaction id.
                        }

                        if (!stateObj.TryReadByte(out byteLength))
                        {
                            return false;
                        }
                        env.oldLength = byteLength;
                        Debug.Assert(env.oldLength == 0 || env.oldLength == 8, "Improper length for old transaction id!");

                        if (env.oldLength > 0)
                        {
                            if (!stateObj.TryReadInt64(out env.oldLongValue))
                            {
                                return false;
                            }
                            Debug.Assert(env.oldLongValue != SqlInternalTransaction.NullTransactionId, "Old transaction id is null?"); // the server guarantees that zero is an invalid transaction id.
                        }
                        else
                        {
                            env.oldLongValue = SqlInternalTransaction.NullTransactionId; // the server guarantees that zero is an invalid transaction id.
                        }

                        // env.length includes 1 byte type token
                        env.length = 3 + env.newLength + env.oldLength;
                        break;

                    case TdsEnums.ENV_LOGSHIPNODE:
                        // env.newBinValue is secondary node, env.oldBinValue is witness node
                        // comes before LoginAck so we can't assert this
                        if (!TryReadTwoStringFields(env, stateObj))
                        {
                            return false;
                        }
                        break;

                    case TdsEnums.ENV_SPRESETCONNECTIONACK:
                        if (!TryReadTwoBinaryFields(env, stateObj))
                        {
                            return false;
                        }
                        break;

                    case TdsEnums.ENV_USERINSTANCE:
                        if (!TryReadTwoStringFields(env, stateObj))
                        {
                            return false;
                        }
                        break;

                    case TdsEnums.ENV_ROUTING:
                        ushort newLength;
                        if (!stateObj.TryReadUInt16(out newLength))
                        {
                            return false;
                        }
                        env.newLength = newLength;
                        byte protocol;
                        if (!stateObj.TryReadByte(out protocol))
                        {
                            return false;
                        }
                        ushort port;
                        if (!stateObj.TryReadUInt16(out port))
                        {
                            return false;
                        }
                        UInt16 serverLen;
                        if (!stateObj.TryReadUInt16(out serverLen))
                        {
                            return false;
                        }
                        string serverName;
                        if (!stateObj.TryReadString(serverLen, out serverName))
                        {
                            return false;
                        }
                        env.newRoutingInfo = new RoutingInfo(protocol, port, serverName);
                        UInt16 oldLength;
                        if (!stateObj.TryReadUInt16(out oldLength))
                        {
                            return false;
                        }
                        if (!stateObj.TrySkipBytes(oldLength))
                        {
                            return false;
                        }
                        env.length = env.newLength + oldLength + 5; // 5=2*sizeof(UInt16)+sizeof(byte) [token+newLength+oldLength]
                        break;

                    // ENVCHANGE tokens not supported by CoreCLR
                    case TdsEnums.ENV_ENLISTDTC:
                    case TdsEnums.ENV_DEFECTDTC:
                    case TdsEnums.ENV_TRANSACTIONENDED:
                    case TdsEnums.ENV_PROMOTETRANSACTION:
                    case TdsEnums.ENV_TRANSACTIONMANAGERADDRESS:
                        throw SQL.UnsupportedFeatureAndToken(_connHandler, ((TdsEnums.EnvChangeType)env.type).ToString());

                    default:
                        Debug.Assert(false, "Unknown environment change token: " + env.type);
                        break;
                }
                processedLength += env.length;
            }

            sqlEnvChange = envarray;
            return true;
        }
Exemplo n.º 10
0
        // Main parse loop for the top-level tds tokens, calls back into the I*Handler interfaces
        internal bool TryRun(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj, out bool dataReady)
        {
            Debug.Assert((SniContext.Undefined != stateObj.SniContext) &&       // SniContext must not be Undefined
                ((stateObj._attentionSent) || ((SniContext.Snix_Execute != stateObj.SniContext) && (SniContext.Snix_SendRows != stateObj.SniContext))),  // SniContext should not be Execute or SendRows unless attention was sent (and, therefore, we are looking for an ACK)
                        String.Format("Unexpected SniContext on call to TryRun; SniContext={0}", stateObj.SniContext));

            if (TdsParserState.Broken == State || TdsParserState.Closed == State)
            {
                dataReady = true;
                return true; // Just in case this is called in a loop, expecting data to be returned.
            }

            dataReady = false;

            do
            {
                // If there is data ready, but we didn't exit the loop, then something is wrong
                Debug.Assert(!dataReady, "dataReady not expected - did we forget to skip the row?");

                if (stateObj._internalTimeout)
                {
                    runBehavior = RunBehavior.Attention;
                }

                if (TdsParserState.Broken == State || TdsParserState.Closed == State)
                    break; // jump out of the loop if the state is already broken or closed.

                if (!stateObj._accumulateInfoEvents && (stateObj._pendingInfoEvents != null))
                {
                    if (RunBehavior.Clean != (RunBehavior.Clean & runBehavior))
                    {
                        SqlConnection connection = null;
                        if (_connHandler != null)
                            connection = _connHandler.Connection; // SqlInternalConnection holds the user connection object as a weak ref
                        // We are omitting checks for error.Class in the code below (see processing of INFO) since we know (and assert) that error class
                        // error.Class < TdsEnums.MIN_ERROR_CLASS for info message. 
                        // Also we know that TdsEnums.MIN_ERROR_CLASS<TdsEnums.MAX_USER_CORRECTABLE_ERROR_CLASS
                        if ((connection != null) && connection.FireInfoMessageEventOnUserErrors)
                        {
                            foreach (SqlError error in stateObj._pendingInfoEvents)
                                FireInfoMessageEvent(connection, stateObj, error);
                        }
                        else
                            foreach (SqlError error in stateObj._pendingInfoEvents)
                                stateObj.AddWarning(error);
                    }
                    stateObj._pendingInfoEvents = null;
                }

                byte token;
                if (!stateObj.TryReadByte(out token))
                {
                    return false;
                }

                if (!IsValidTdsToken(token))
                {
                    Debug.Assert(false, String.Format((IFormatProvider)null, "unexpected token; token = {0,-2:X2}", token));
                    _state = TdsParserState.Broken;
                    _connHandler.BreakConnection();
                    throw SQL.ParsingError();
                }

                int tokenLength;
                if (!TryGetTokenLength(token, stateObj, out tokenLength))
                {
                    return false;
                }

                switch (token)
                {
                    case TdsEnums.SQLERROR:
                    case TdsEnums.SQLINFO:
                        {
                            if (token == TdsEnums.SQLERROR)
                            {
                                stateObj._errorTokenReceived = true; // Keep track of the fact error token was received - for Done processing.
                            }

                            SqlError error;
                            if (!TryProcessError(token, stateObj, out error))
                            {
                                return false;
                            }

                            if (token == TdsEnums.SQLINFO && stateObj._accumulateInfoEvents)
                            {
                                Debug.Assert(error.Class < TdsEnums.MIN_ERROR_CLASS, "INFO with class > TdsEnums.MIN_ERROR_CLASS");

                                if (stateObj._pendingInfoEvents == null)
                                    stateObj._pendingInfoEvents = new List<SqlError>();
                                stateObj._pendingInfoEvents.Add(error);
                                stateObj._syncOverAsync = true;
                                break;
                            }

                            if (RunBehavior.Clean != (RunBehavior.Clean & runBehavior))
                            {
                                // If FireInfoMessageEventOnUserErrors is true, we have to fire event without waiting.
                                // Otherwise we can go ahead and add it to errors/warnings collection.
                                SqlConnection connection = null;
                                if (_connHandler != null)
                                    connection = _connHandler.Connection; // SqlInternalConnection holds the user connection object as a weak ref

                                if ((connection != null) &&
                                    (connection.FireInfoMessageEventOnUserErrors == true) &&
                                    (error.Class <= TdsEnums.MAX_USER_CORRECTABLE_ERROR_CLASS))
                                {
                                    // Fire SqlInfoMessage here
                                    FireInfoMessageEvent(connection, stateObj, error);
                                }
                                else
                                {
                                    // insert error/info into the appropriate exception - warning if info, exception if error
                                    if (error.Class < TdsEnums.MIN_ERROR_CLASS)
                                    {
                                        stateObj.AddWarning(error);
                                    }
                                    else if (error.Class < TdsEnums.FATAL_ERROR_CLASS)
                                    {
                                        // Continue results processing for all non-fatal errors (<20)

                                        stateObj.AddError(error);

                                        // Add it to collection - but do NOT change run behavior UNLESS
                                        // we are in an ExecuteReader call - at which time we will be throwing
                                        // anyways so we need to consume all errors.  This is not the case
                                        // if we have already given out a reader.  If we have already given out
                                        // a reader we need to throw the error but not halt further processing.  We used to
                                        // halt processing.

                                        if (null != dataStream)
                                        {
                                            if (!dataStream.IsInitialized)
                                            {
                                                runBehavior = RunBehavior.UntilDone;
                                            }
                                        }
                                    }
                                    else
                                    {
                                        stateObj.AddError(error);

                                        // Else we have a fatal error and we need to change the behavior
                                        // since we want the complete error information in the exception.
                                        // Besides - no further results will be received.
                                        runBehavior = RunBehavior.UntilDone;
                                    }
                                }
                            }
                            else if (error.Class >= TdsEnums.FATAL_ERROR_CLASS)
                            {
                                stateObj.AddError(error);
                            }
                            break;
                        }

                    case TdsEnums.SQLCOLINFO:
                        {
                            if (null != dataStream)
                            {
                                _SqlMetaDataSet metaDataSet;
                                if (!TryProcessColInfo(dataStream.MetaData, dataStream, stateObj, out metaDataSet))
                                {
                                    return false;
                                }
                                if (!dataStream.TrySetMetaData(metaDataSet, false))
                                {
                                    return false;
                                }
                                dataStream.BrowseModeInfoConsumed = true;
                            }
                            else
                            { // no dataStream
                                if (!stateObj.TrySkipBytes(tokenLength))
                                {
                                    return false;
                                }
                            }
                            break;
                        }

                    case TdsEnums.SQLDONE:
                    case TdsEnums.SQLDONEPROC:
                    case TdsEnums.SQLDONEINPROC:
                        {
                            // RunBehavior can be modified
                            if (!TryProcessDone(cmdHandler, dataStream, ref runBehavior, stateObj))
                            {
                                return false;
                            }
                            if ((token == TdsEnums.SQLDONEPROC) && (cmdHandler != null))
                            {
                                cmdHandler.OnDoneProc();
                            }

                            break;
                        }

                    case TdsEnums.SQLORDER:
                        {
                            // don't do anything with the order token so read off the pipe
                            if (!stateObj.TrySkipBytes(tokenLength))
                            {
                                return false;
                            }
                            break;
                        }

                    case TdsEnums.SQLALTMETADATA:
                        {
                            stateObj.CloneCleanupAltMetaDataSetArray();

                            if (stateObj._cleanupAltMetaDataSetArray == null)
                            {
                                // create object on demand (lazy creation)
                                stateObj._cleanupAltMetaDataSetArray = new _SqlMetaDataSetCollection();
                            }

                            _SqlMetaDataSet cleanupAltMetaDataSet;
                            if (!TryProcessAltMetaData(tokenLength, stateObj, out cleanupAltMetaDataSet))
                            {
                                return false;
                            }

                            stateObj._cleanupAltMetaDataSetArray.SetAltMetaData(cleanupAltMetaDataSet);
                            if (null != dataStream)
                            {
                                byte metadataConsumedByte;
                                if (!stateObj.TryPeekByte(out metadataConsumedByte))
                                {
                                    return false;
                                }
                                if (!dataStream.TrySetAltMetaDataSet(cleanupAltMetaDataSet, (TdsEnums.SQLALTMETADATA != metadataConsumedByte)))
                                {
                                    return false;
                                }
                            }

                            break;
                        }

                    case TdsEnums.SQLALTROW:
                        {
                            if (!stateObj.TryStartNewRow(isNullCompressed: false))
                            { // altrows are not currently null compressed
                                return false;
                            }

                            // read will call run until dataReady. Must not read any data if returnimmetiately set
                            if (RunBehavior.ReturnImmediately != (RunBehavior.ReturnImmediately & runBehavior))
                            {
                                ushort altRowId;
                                if (!stateObj.TryReadUInt16(out altRowId))
                                { // get altRowId
                                    return false;
                                }

                                if (!TrySkipRow(stateObj._cleanupAltMetaDataSetArray.GetAltMetaData(altRowId), stateObj))
                                { // skip altRow
                                    return false;
                                }
                            }
                            else
                            {
                                dataReady = true;
                            }

                            break;
                        }

                    case TdsEnums.SQLENVCHANGE:
                        {
                            // ENVCHANGE must be processed synchronously (since it can modify the state of many objects)
                            stateObj._syncOverAsync = true;

                            SqlEnvChange[] env;
                            if (!TryProcessEnvChange(tokenLength, stateObj, out env))
                            {
                                return false;
                            }

                            for (int ii = 0; ii < env.Length; ii++)
                            {
                                if (env[ii] != null && !this.Connection.IgnoreEnvChange)
                                {
                                    switch (env[ii].type)
                                    {
                                        case TdsEnums.ENV_BEGINTRAN:
                                            // When we get notification from the server of a new
                                            // transaction, we move any pending transaction over to
                                            // the current transaction, then we store the token in it.
                                            // if there isn't a pending transaction, then it's either
                                            // a TSQL transaction or a distributed transaction.
                                            Debug.Assert(null == _currentTransaction, "non-null current transaction with an ENV Change");
                                            _currentTransaction = _pendingTransaction;
                                            _pendingTransaction = null;

                                            if (null != _currentTransaction)
                                            {
                                                _currentTransaction.TransactionId = env[ii].newLongValue;   // this is defined as a ULongLong in the server and in the TDS Spec.
                                            }
                                            else
                                            {
                                                TransactionType transactionType = TransactionType.LocalFromTSQL;
                                                _currentTransaction = new SqlInternalTransaction(_connHandler, transactionType, null, env[ii].newLongValue);
                                            }
                                            if (null != _statistics && !_statisticsIsInTransaction)
                                            {
                                                _statistics.SafeIncrement(ref _statistics._transactions);
                                            }
                                            _statisticsIsInTransaction = true;
                                            break;
                                        case TdsEnums.ENV_COMMITTRAN:
                                            // SQLHOT 483
                                            //  Must clear the retain id if the server-side transaction ends by anything other
                                            //  than rollback.
                                            goto case TdsEnums.ENV_ROLLBACKTRAN;
                                        case TdsEnums.ENV_ROLLBACKTRAN:
                                            // When we get notification of a completed transaction
                                            // we null out the current transaction.
                                            if (null != _currentTransaction)
                                            {
#if DEBUG
                                                // Check null for case where Begin and Rollback obtained in the same message.
                                                if (SqlInternalTransaction.NullTransactionId != _currentTransaction.TransactionId)
                                                {
                                                    Debug.Assert(_currentTransaction.TransactionId != env[ii].newLongValue, "transaction id's are not equal!");
                                                }
#endif

                                                if (TdsEnums.ENV_COMMITTRAN == env[ii].type)
                                                {
                                                    _currentTransaction.Completed(TransactionState.Committed);
                                                }
                                                else if (TdsEnums.ENV_ROLLBACKTRAN == env[ii].type)
                                                {
                                                    //  Hold onto transaction id if distributed tran is rolled back.  This must
                                                    //  be sent to the server on subsequent executions even though the transaction
                                                    //  is considered to be rolled back.
                                                    _currentTransaction.Completed(TransactionState.Aborted);
                                                }
                                                else
                                                {
                                                    _currentTransaction.Completed(TransactionState.Unknown);
                                                }
                                                _currentTransaction = null;
                                            }
                                            _statisticsIsInTransaction = false;
                                            break;
                                        case TdsEnums.ENV_ENLISTDTC:
                                        case TdsEnums.ENV_DEFECTDTC:
                                        case TdsEnums.ENV_TRANSACTIONENDED:
                                            Debug.Assert(false, "Should have thrown if DTC token encountered");
                                            break;
                                        default:
                                            _connHandler.OnEnvChange(env[ii]);
                                            break;
                                    }
                                }
                            }
                            break;
                        }
                    case TdsEnums.SQLLOGINACK:
                        {
                            SqlLoginAck ack;
                            if (!TryProcessLoginAck(stateObj, out ack))
                            {
                                return false;
                            }

                            _connHandler.OnLoginAck(ack);
                            break;
                        }
                    case TdsEnums.SQLFEATUREEXTACK:
                        {
                            if (!TryProcessFeatureExtAck(stateObj))
                            {
                                return false;
                            }
                            break;
                        }
                    case TdsEnums.SQLSESSIONSTATE:
                        {
                            if (!TryProcessSessionState(stateObj, tokenLength, _connHandler._currentSessionData))
                            {
                                return false;
                            }
                            break;
                        }
                    case TdsEnums.SQLCOLMETADATA:
                        {
                            if (tokenLength != TdsEnums.VARNULL)
                            {
                                _SqlMetaDataSet metadata;
                                if (!TryProcessMetaData(tokenLength, stateObj, out metadata))
                                {
                                    return false;
                                }
                                stateObj._cleanupMetaData = metadata;
                            }
                            else
                            {
                                if (cmdHandler != null)
                                {
                                    stateObj._cleanupMetaData = cmdHandler.MetaData;
                                }
                            }

                            if (null != dataStream)
                            {
                                byte peekedToken;
                                if (!stateObj.TryPeekByte(out peekedToken))
                                { // temporarily cache next byte
                                    return false;
                                }

                                if (!dataStream.TrySetMetaData(stateObj._cleanupMetaData, (TdsEnums.SQLTABNAME == peekedToken || TdsEnums.SQLCOLINFO == peekedToken)))
                                {
                                    return false;
                                }
                            }
                            else if (null != bulkCopyHandler)
                            {
                                bulkCopyHandler.SetMetaData(stateObj._cleanupMetaData);
                            }
                            break;
                        }
                    case TdsEnums.SQLROW:
                    case TdsEnums.SQLNBCROW:
                        {
                            Debug.Assert(stateObj._cleanupMetaData != null, "Reading a row, but the metadata is null");

                            if (token == TdsEnums.SQLNBCROW)
                            {
                                if (!stateObj.TryStartNewRow(isNullCompressed: true, nullBitmapColumnsCount: stateObj._cleanupMetaData.Length))
                                {
                                    return false;
                                }
                            }
                            else
                            {
                                if (!stateObj.TryStartNewRow(isNullCompressed: false))
                                {
                                    return false;
                                }
                            }

                            if (null != bulkCopyHandler)
                            {
                                if (!TryProcessRow(stateObj._cleanupMetaData, bulkCopyHandler.CreateRowBuffer(), bulkCopyHandler.CreateIndexMap(), stateObj))
                                {
                                    return false;
                                }
                            }
                            else if (RunBehavior.ReturnImmediately != (RunBehavior.ReturnImmediately & runBehavior))
                            {
                                if (!TrySkipRow(stateObj._cleanupMetaData, stateObj))
                                { // skip rows
                                    return false;
                                }
                            }
                            else
                            {
                                dataReady = true;
                            }

                            if (_statistics != null)
                            {
                                _statistics.WaitForDoneAfterRow = true;
                            }
                            break;
                        }
                    case TdsEnums.SQLRETURNSTATUS:
                        int status;
                        if (!stateObj.TryReadInt32(out status))
                        {
                            return false;
                        }
                        if (cmdHandler != null)
                        {
                            cmdHandler.OnReturnStatus(status);
                        }
                        break;
                    case TdsEnums.SQLRETURNVALUE:
                        {
                            SqlReturnValue returnValue;
                            if (!TryProcessReturnValue(tokenLength, stateObj, out returnValue))
                            {
                                return false;
                            }
                            if (cmdHandler != null)
                            {
                                cmdHandler.OnReturnValue(returnValue);
                            }
                            break;
                        }
                    case TdsEnums.SQLSSPI:
                        {
                            // token length is length of SSPI data - call ProcessSSPI with it

                            Debug.Assert(stateObj._syncOverAsync, "ProcessSSPI does not support retry, do not attempt asynchronously");
                            stateObj._syncOverAsync = true;

                            ProcessSSPI(tokenLength);
                            break;
                        }
                    case TdsEnums.SQLTABNAME:
                        {
                            {
                                if (!stateObj.TrySkipBytes(tokenLength))
                                {
                                    return false;
                                }
                            }
                            break;
                        }

                    default:
                        Debug.Assert(false, "Unhandled token:  " + token.ToString(CultureInfo.InvariantCulture));
                        break;
                }

                Debug.Assert(stateObj._pendingData || !dataReady, "dataReady is set, but there is no pending data");
            }

            // Loop while data pending & runbehavior not return immediately, OR
            // if in attention case, loop while no more pending data & attention has not yet been
            // received.
            while ((stateObj._pendingData &&
                    (RunBehavior.ReturnImmediately != (RunBehavior.ReturnImmediately & runBehavior))) ||
                (!stateObj._pendingData && stateObj._attentionSent && !stateObj._attentionReceived));

#if DEBUG
            if ((stateObj._pendingData) && (!dataReady))
            {
                byte token;
                if (!stateObj.TryPeekByte(out token))
                {
                    return false;
                }
                Debug.Assert(IsValidTdsToken(token), string.Format("DataReady is false, but next token is not valid: {0,-2:X2}", token));
            }
#endif

            if (!stateObj._pendingData)
            {
                if (null != CurrentTransaction)
                {
                    CurrentTransaction.Activate();
                }
            }

            // if we recieved an attention (but this thread didn't send it) then
            // we throw an Operation Cancelled error
            if (stateObj._attentionReceived)
            {
                // Dev11 #344723: SqlClient stress hang System_Data!Tcp::ReadSync via a call to SqlDataReader::Close
                // Spin until SendAttention has cleared _attentionSending, this prevents a race condition between receiving the attention ACK and setting _attentionSent
                SpinWait.SpinUntil(() => !stateObj._attentionSending);

                Debug.Assert(stateObj._attentionSent, "Attention ACK has been received without attention sent");
                if (stateObj._attentionSent)
                {
                    // Reset attention state.
                    stateObj._attentionSent = false;
                    stateObj._attentionReceived = false;

                    if (RunBehavior.Clean != (RunBehavior.Clean & runBehavior) && !stateObj._internalTimeout)
                    {
                        // Add attention error to collection - if not RunBehavior.Clean!
                        stateObj.AddError(new SqlError(0, 0, TdsEnums.MIN_ERROR_CLASS, _server, SQLMessage.OperationCancelled(), "", 0));
                    }
                }
            }

            if (stateObj.HasErrorOrWarning)
            {
                ThrowExceptionAndWarning(stateObj);
            }
            return true;
        }
Exemplo n.º 11
0
        internal bool TryProcessAltMetaData(int cColumns, TdsParserStateObject stateObj, out _SqlMetaDataSet metaData) {
            Debug.Assert(cColumns > 0, "should have at least 1 column in altMetaData!");

            metaData = null;
            _SqlMetaDataSet altMetaDataSet = new _SqlMetaDataSet(cColumns, null);
            int[] indexMap = new int[cColumns];

            if (!stateObj.TryReadUInt16(out altMetaDataSet.id)) {
                return false;
            }

            byte byCols;
            if (!stateObj.TryReadByte(out byCols)) {
                return false;
            }

            while (byCols > 0) {
                if (!stateObj.TrySkipBytes(2)) { // ignore ColNum ...
                    return false;
                }
                byCols--;
            }

            // pass 1, read the meta data off the wire
            for (int i = 0; i < cColumns; i++) {
                // internal meta data class
                _SqlMetaData col = altMetaDataSet[i];

                if (!stateObj.TryReadByte(out col.op)) {
                    return false;
                }
                if (!stateObj.TryReadUInt16(out col.operand)) {
                    return false;
                }

                // TCE is not applicable to AltMetadata.
                if (!TryCommonProcessMetaData(stateObj, col, null, fColMD: false, columnEncryptionSetting: SqlCommandColumnEncryptionSetting.Disabled)) {
                    return false;
                }

                if (ADP.IsEmpty(col.column)) {
                    // create column name from op
                    switch (col.op) {
                        case TdsEnums.AOPAVG:
                            col.column = "avg";
                            break;

                        case TdsEnums.AOPCNT:
                            col.column = "cnt";
                            break;

                        case TdsEnums.AOPCNTB:
                            col.column = "cntb";
                            break;

                        case TdsEnums.AOPMAX:
                            col.column = "max";
                            break;

                        case TdsEnums.AOPMIN:
                            col.column = "min";
                            break;

                        case TdsEnums.AOPSUM:
                            col.column = "sum";
                            break;

                        case TdsEnums.AOPANY:
                            col.column = "any";
                            break;

                        case TdsEnums.AOPNOOP:
                            col.column = "noop";
                            break;

                        case TdsEnums.AOPSTDEV:
                            col.column = "stdev";
                            break;

                        case TdsEnums.AOPSTDEVP:
                            col.column = "stdevp";
                            break;

                        case TdsEnums.AOPVAR:
                            col.column = "var";
                            break;

                        case TdsEnums.AOPVARP:
                            col.column = "varp";
                            break;
                    }
                }
                indexMap[i] = i;
            }

            altMetaDataSet.indexMap = indexMap;
            altMetaDataSet.visibleColumns = cColumns;

            metaData = altMetaDataSet;
            return true;
        }