67 lines
1.8 KiB
Python
67 lines
1.8 KiB
Python
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from dataclasses import dataclass, field
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from io import BufferedRandom
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from os.path import getsize
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from time import time
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@dataclass
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class Shard:
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size: int
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file: BufferedRandom
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file_size: int
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@staticmethod
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def load_shard(filename: str) -> 'Shard':
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file = open(filename, 'r+b')
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size = int.from_bytes(file.read(8), 'big')
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file.seek(0, 2)
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file_size = file.tell()
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return Shard(size, file, file_size)
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def write_entry(self, entry: 'Entry'):
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data = entry.to_bytes()
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data_length = len(data)
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if self.size + 1 + data_length > self.file_size:
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raise EOFError()
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self.file.seek(self.size + 1)
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self.file.write(data)
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self.size += data_length
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self.file.seek(0)
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self.file.write(self.size.to_bytes(8, 'big'))
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def close(self):
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self.file.close()
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@dataclass
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class Entry:
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shard: Shard
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timestamp_start: int = field(default_factory=lambda: int(time()))
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timestamp_end: int = field(default_factory=lambda: int(time()))
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content: bytes = field(default_factory=bytes)
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@staticmethod
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def from_bytes(shard: Shard, data: BufferedRandom) -> 'Entry':
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timestamp_start = int.from_bytes(data.read(8), 'big')
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timestamp_end = int.from_bytes(data.read(8), 'big')
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content_length = int.from_bytes(data.read(8), 'big')
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content = data.read(content_length)
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return Entry(shard, timestamp_start, timestamp_end, content)
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def to_bytes(self) -> bytes:
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data = self.timestamp_start.to_bytes(8, 'big')
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data += self.timestamp_end.to_bytes(8, 'big')
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data += len(self.content).to_bytes(8, 'big')
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data += self.content
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return data
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def add_content(self, content: bytes):
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self.timestamp_end = int(time())
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self.content += content
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