paimon-python/pypaimon/index/data_evolution_index_source_meta.py

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"""Java DataEvolutionIndexSourceMeta stored in GlobalIndexMeta.source_meta."""

import struct
from dataclasses import dataclass


@dataclass(frozen=True)
class DataEvolutionIndexSourceMeta:
    scan_snapshot_id: int

    MAGIC = 0x44454958
    VERSION = 1

    def __post_init__(self):
        if self.scan_snapshot_id <= 0:
            raise ValueError('Scan snapshot id must be positive.')

    def serialize(self):
        return struct.pack('>iiq', self.MAGIC, self.VERSION, self.scan_snapshot_id)

    @classmethod
    def is_data_evolution_meta(cls, data):
        return data is not None and len(data) >= 4 and data[:4] == b'DEIX'

    @classmethod
    def deserialize(cls, data):
        if len(data) != 16 or not cls.is_data_evolution_meta(data):
            raise ValueError('Invalid data-evolution index source metadata.')
        _, version, snapshot_id = struct.unpack('>iiq', data)
        if version != cls.VERSION:
            raise ValueError('Unsupported data-evolution index source version: {}.'.format(version))
        return cls(snapshot_id)