Add PyReader and PyWriter ABC

chdb/rwabc.py

@@ -0,0 +1,64 @@
+from abc import ABC, abstractmethod
+from typing import List, Any
+
+
+class PyReader(ABC):
+    def __init__(self, data: Any):
+        """
+        Initialize the reader with data. The exact type and structure of `data` can vary.
+
+        Args:
+            data (Any): The data with which to initialize the reader, format and type are not strictly defined.
+        """
+        self.data = data
+
+    @abstractmethod
+    def read(self, col_names: List[str], count: int) -> bytes:
+        """
+        Read a specified number of rows from the given columns. Must be implemented by subclasses.
+
+        Args:
+            col_names (List[str]): List of column names to read.
+            count (int): Maximum number of rows to read.
+
+        Returns:
+            bytes: Serialized data representing the requested rows.
+        """
+        pass
+
+
+class PyWriter(ABC):
+    def __init__(self, col_names: List[str], types: List[type], data: Any):
+        """
+        Initialize the writer with column names, their types, and initial data.
+
+        Args:
+            col_names (List[str]): List of column names.
+            types (List[type]): List of types corresponding to each column.
+            data (Any): Initial data to setup the writer, format and type are not strictly defined.
+        """
+        self.col_names = col_names
+        self.types = types
+        self.data = data
+        self.blocks = []
+
+    @abstractmethod
+    def write(self, col_names: List[str], columns: List[List[Any]]) -> None:
+        """
+        Save columns of data to blocks. Must be implemented by subclasses.
+
+        Args:
+            col_names (List[str]): List of column names that are being written.
+            columns (List[List[Any]]): List of columns data, each column is represented by a list.
+        """
+        pass
+
+    @abstractmethod
+    def finalize(self) -> bytes:
+        """
+        Assemble and return the final data from blocks. Must be implemented by subclasses.
+
+        Returns:
+            bytes: The final serialized data.
+        """
+        pass