from abc import ABC, abstractmethod
from typing import Sequence, Any

Matrix = Sequence[Sequence[Any]]


class Closable(ABC):
    @abstractmethod
    def close(self):
        pass


class ByteSource(Closable):
    last_message:bytes = None

    @abstractmethod
    def read_leb128(self) -> int:
        pass

    @abstractmethod
    def read_leb128_str(self) -> str:
        pass

    @abstractmethod
    def read_uint64(self) -> int:
        pass

    @abstractmethod
    def read_bytes(self, sz: int) -> bytes:
        pass

    @abstractmethod
    def read_str_col(self, num_rows: int, encoding: str, nullable: bool = False, null_obj: Any = None):
        pass

    @abstractmethod
    def read_bytes_col(self, sz: int, num_rows: int):
        pass

    @abstractmethod
    def read_fixed_str_col(self, sz: int, num_rows: int, encoding: str):
        pass

    @abstractmethod
    def read_array(self, array_type: str, num_rows: int):
        pass

    @abstractmethod
    def read_byte(self) -> int:
        pass