Source code for dfvfs.file_io.apfs_file_io

# -*- coding: utf-8 -*-
"""The Apple File System (APFS) file-like object implementation."""

import os

from dfvfs.file_io import file_io
from dfvfs.lib import errors
from dfvfs.resolver import resolver


[docs] class APFSFile(file_io.FileIO): """File input/output (IO) object using pyfsapfs.file_entry."""
[docs] def __init__(self, resolver_context, path_spec): """Initializes a file input/output (IO) object. Args: resolver_context (Context): resolver context. path_spec (PathSpec): a path specification. """ super(APFSFile, self).__init__(resolver_context, path_spec) self._file_system = None self._fsapfs_file_entry = None
def _Close(self): """Closes the file-like object.""" self._file_system = None self._fsapfs_file_entry = None def _Open(self, mode='rb'): """Opens the file-like object defined by path specification. Args: mode (Optional[str]): file access mode. Raises: AccessError: if the access to open the file was denied. IOError: if the file-like object could not be opened. NotSupported: if a data stream, like the resource or named fork, is requested to be opened. OSError: if the file-like object could not be opened. PathSpecError: if the path specification is incorrect. """ data_stream = getattr(self._path_spec, 'data_stream', None) if data_stream: raise errors.NotSupported( f'Open data stream: {data_stream:s} not supported.') self._file_system = resolver.Resolver.OpenFileSystem( self._path_spec, resolver_context=self._resolver_context) file_entry = self._file_system.GetFileEntryByPathSpec(self._path_spec) if not file_entry: raise IOError('Unable to open file entry.') fsapfs_file_entry = file_entry.GetAPFSFileEntry() if not fsapfs_file_entry: raise IOError('Unable to open APFS file entry.') self._fsapfs_file_entry = fsapfs_file_entry # Note: that the following functions do not follow the style guide # because they are part of the file-like object interface. # pylint: disable=invalid-name
[docs] def read(self, size=None): """Reads a byte string from the file-like object at the current offset. The function will read a byte string of the specified size or all of the remaining data if no size was specified. Args: size (Optional[int]): number of bytes to read, where None is all remaining data. Returns: bytes: data read. Raises: IOError: if the read failed. OSError: if the read failed. """ if not self._is_open: raise IOError('Not opened.') return self._fsapfs_file_entry.read(size=size)
[docs] def seek(self, offset, whence=os.SEEK_SET): """Seeks to an offset within the file-like object. Args: offset (int): offset to seek to. whence (Optional(int)): value that indicates whether offset is an absolute or relative position within the file. Raises: IOError: if the seek failed. OSError: if the seek failed. """ if not self._is_open: raise IOError('Not opened.') self._fsapfs_file_entry.seek(offset, whence)
[docs] def get_offset(self): """Retrieves the current offset into the file-like object. Return: int: current offset into the file-like object. Raises: IOError: if the file-like object has not been opened. OSError: if the file-like object has not been opened. """ if not self._is_open: raise IOError('Not opened.') return self._fsapfs_file_entry.get_offset()
[docs] def get_size(self): """Retrieves the size of the file-like object. Returns: int: size of the file-like object data. Raises: IOError: if the file-like object has not been opened. OSError: if the file-like object has not been opened. """ if not self._is_open: raise IOError('Not opened.') return self._fsapfs_file_entry.get_size()