90 lines
2.8 KiB
Python
90 lines
2.8 KiB
Python
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import os
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import hashlib
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class FileReader:
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"""
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实现01-文件读取.md描述的 file_reader 模块。
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功能描述：
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- 支持流式读取大文件，不阻塞内存。
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- 校验文件存在性及可读性。
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- 实时计算总大小和SHA-256哈希值。
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"""
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def __init__(self, file_path: str, chunk_size: int = 1 * 1024 * 1024):
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"""
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A[接收文件路径 + 卷大小]
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Args:
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file_path (str): 目标文件的路径。
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chunk_size (int): 单次读取的数据块大小（字节），默认1MB。
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"""
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self.file_path = file_path
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self.chunk_size = chunk_size
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# B["文件存在 / 可读 ?"] -> 校验节点
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if not os.path.exists(file_path):
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raise FileNotFoundError(f"文件不存在: {file_path}")
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if not os.access(file_path, os.R_OK):
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raise PermissionError(f"无读权限: {file_path}")
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def __iter__(self):
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# C["打开二进制流"]
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self._total_size = 0
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self._sha256_hash = hashlib.sha256()
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with open(self.file_path, 'rb') as f:
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while True:
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chunk = f.read(self.chunk_size)
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# E["EOF ?"] -> 检查文件是否结束
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if not chunk:
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break
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# 更新元数据状态 (对应F节点输出的元信息)
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self._total_size += len(chunk)
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self._sha256_hash.update(chunk)
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yield chunk
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@property
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def total_size(self) -> int:
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"""返回文件总大小"""
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return self._total_size
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@property
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def sha256_hash(self) -> str:
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"""返回SHA-256哈希值"""
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return self._sha256_hash.hexdigest()
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# --- 使用示例 (Usage Example) ---
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if __name__ == "__main__":
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try:
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# 初始化读取器
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reader = FileReader("kali-2026.zip", chunk_size=1024*1024)
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print(f"开始读取...")
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total_chunks = 0
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# D/E/F节点逻辑：遍历数据流并模拟下游处理
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for data_chunk in reader:
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# 此处模拟传递给 crypto 加密引擎
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# process_crypto_engine(data_chunk)
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total_chunks += 1
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# 可选：实时查看进度 (实际工程中通常由外部状态管理模块处理)
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print(f"已读取第 {total_chunks} 块数据，当前大小: {reader.total_size} bytes")
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print("-" * 30)
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print(f"文件读取完毕。")
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print(f"总大小: {reader.total_size} bytes")
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print(f"SHA-256: {reader.sha256_hash}")
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except Exception as e:
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# B节点报错处理
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print(f"读取失败: {e}")
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