func (c *FrontendConnection) readDescribeMessage(msg *fbcore.Message) (byte, error) {
	typ, err := fbbuf.ReadByte(msg.Payload())
	if err != nil {
		return 0, err
	}
	if typ != 'S' && typ != 'P' {
		return 0, fmt.Errorf("invalid type %q", typ)
	}
	statementName, err := fbbuf.ReadCString(msg.Payload())
	if err != nil {
		return 0, err
	}
	if statementName != "" {
		return 0, fmt.Errorf("tried to use statement/portal name %q; only unnamed statements and portals are supported")
	}
	// TODO: ensure we're at the end of the packet
	return typ, nil
}
Esempio n. 2
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func parseLogRecord(
	dst *logRecord, data []byte, exit exitFn) {

	b := bytes.NewBuffer(data)

	// Read the next nullable string from b, returning a 'nil'
	// *string should it be null.
	nextNullableString := func() *string {
		np, err := buf.ReadByte(b)
		if err != nil {
			exit(err)
		}

		switch np {
		case 'P':
			s, err := buf.ReadCString(b)
			if err != nil {
				exit(err)
			}

			return &s

		case 'N':
			// 'N' is still followed by a NUL byte that
			// must be consumed.
			_, err := buf.ReadCString(b)
			if err != nil {
				exit(err)
			}

			return nil

		default:
			exit("Expected nullable string "+
				"control character, got %c", np)

		}

		exit("Prior switch should always return")
		panic("exit should panic/return, " +
			"but the compiler doesn't know that")
	}

	// Read a non-nullable string from b
	nextString := func() string {
		s, err := buf.ReadCString(b)
		if err != nil {
			exit(err)
		}

		return s
	}

	nextInt32 := func() int32 {
		i32, err := buf.ReadInt32(b)
		if err != nil {
			exit(err)
		}

		return i32
	}

	nextInt64 := func() int64 {
		i64, err := readInt64(b)
		if err != nil {
			exit(err)
		}

		return i64
	}

	nextUint64 := func() uint64 {
		ui64, err := readUint64(b)
		if err != nil {
			exit(err)
		}

		return ui64
	}

	dst.LogTime = nextString()
	dst.UserName = nextNullableString()
	dst.DatabaseName = nextNullableString()
	dst.Pid = nextInt32()
	dst.ClientAddr = nextNullableString()
	dst.SessionID = nextString()
	dst.SeqNum = nextInt64()
	dst.PsDisplay = nextNullableString()
	dst.SessionStart = nextString()
	dst.Vxid = nextNullableString()
	dst.Txid = nextUint64()
	dst.ELevel = nextInt32()
	dst.SQLState = nextNullableString()
	dst.ErrMessage = nextNullableString()
	dst.ErrDetail = nextNullableString()
	dst.ErrHint = nextNullableString()
	dst.InternalQuery = nextNullableString()
	dst.InternalQueryPos = nextInt32()
	dst.ErrContext = nextNullableString()
	dst.UserQuery = nextNullableString()
	dst.UserQueryPos = nextInt32()
	dst.FileErrPos = nextNullableString()
	dst.ApplicationName = nextNullableString()

	if b.Len() != 0 {
		exit("LogRecord message has mismatched "+
			"length header and cString contents: remaining %d",
			b.Len())
	}
}