132 lines
4.6 KiB
Python
132 lines
4.6 KiB
Python
import os
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def GetVolumeLetter() -> str:
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from ntfs_utils.main import volume_letter
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return volume_letter
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def CopySingleFragmentFiles(source_data_dict, target_path):
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"""
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根据起始字节和长度，从磁盘中读取数据并保存为目标文件
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:param source_data_dict: 包含源数据信息的字典
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:param target_path: 目标文件夹路径
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"""
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start_byte = source_data_dict.get("start_byte")
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byte_length = source_data_dict.get("length")
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absolute_path = source_data_dict.get("absolute_path")
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file_name = source_data_dict.get("filename")
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if byte_length <= 0:
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print("错误：字节长度无效")
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return
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if not absolute_path or not file_name:
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print("错误：缺少必要的文件信息")
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return
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source_disk_path = GetVolumeLetter()
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target_file_path = os.path.join(target_path, file_name)
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try:
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# 创建目标目录（如果不存在）
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os.makedirs(target_path, exist_ok=True)
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with open(fr"\\.\{source_disk_path}:", 'rb') as disk:
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disk.seek(start_byte)
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with open(target_file_path, 'wb') as f:
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remaining = byte_length
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CHUNK_SIZE = 1024 * 1024 # 1MB
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while remaining > 0:
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read_size = min(CHUNK_SIZE, remaining)
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chunk = disk.read(read_size)
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if not chunk:
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print("警告：读取到空数据，可能已到达磁盘末尾。")
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break
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f.write(chunk)
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remaining -= len(chunk)
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print(
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f"成功：已从字节偏移量 {start_byte} 读取 {byte_length} 字节，保存为 {target_file_path}")
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except PermissionError:
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print("错误：需要管理员权限访问磁盘设备，请以管理员身份运行此程序")
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except Exception as e:
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print(f"发生错误: {str(e)}")
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def ReadDiskBytes(volume_letter: str, start_byte: int, length: int) -> bytes:
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"""
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从指定磁盘的指定起始位置读取指定长度的字节。
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:param volume_letter: 盘符（如 "Y"）
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:param start_byte: 起始字节位置（整数）
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:param length: 要读取的字节数（整数）
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:return: 读取到的原始字节数据（bytes）
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"""
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if not isinstance(volume_letter, str) or len(volume_letter.strip()) != 1:
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raise ValueError("drive_letter 必须是单个字母，如 'Y'")
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# 构建 Windows 设备路径格式：\\.\Y:
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disk_path = f"\\\\.\\{volume_letter.strip().upper()}:"
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try:
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with open(disk_path, "rb") as disk:
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disk.seek(start_byte)
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data = disk.read(length)
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return data
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except PermissionError:
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raise PermissionError("权限不足，请以管理员身份运行程序")
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except Exception as e:
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raise RuntimeError(f"读取磁盘失败：{e}")
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def CopyMultiFragmentFiles(
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item: dict,
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fragment_lists: dict,
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target_path: str
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):
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"""
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处理具有多个分片的文件，读取并按顺序拼接内容，最终写入磁盘。
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:param item: 包含文件分片信息的字典
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:param fragment_lists: 存储各文件分片内容的字典
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:param target_path: 恢复文件的目标保存路径
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:return: None
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"""
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file_name = item['filename']
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extent_count = item['extent_count']
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fragment_index = item['fragment_index']
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start_byte = item['start_byte']
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length_byte = item['length']
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volume_letter = GetVolumeLetter()
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# 读取分片内容
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fragment_content = ReadDiskBytes(volume_letter, start_byte, length_byte)
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# 如果还没有为这个文件创建列表，则初始化
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if file_name not in fragment_lists:
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fragment_lists[file_name] = [None] * extent_count
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# 将内容插入到指定位置
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if fragment_index <= extent_count:
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fragment_lists[file_name][fragment_index - 1] = fragment_content
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print(f"已写入 {file_name} 的第 {fragment_index} 个片段。")
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else:
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print(f"警告：{file_name} 的 fragment_index 超出范围：{fragment_index} / {extent_count}")
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# 检查是否所有分片都已加载
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fragments = fragment_lists[file_name]
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if None not in fragments:
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full_content = b''.join(fragments)
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target_file_path = os.path.join(target_path, file_name)
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try:
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with open(target_file_path, 'wb') as f:
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f.write(full_content)
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print(f"已成功恢复文件：{file_name}")
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except Exception as e:
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print(f"写入文件失败：{file_name}，错误：{e}")
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