# -*- coding: utf-8 -*-
"""The HFS file system implementation."""
import pyfshfs
from dfvfs.lib import definitions
from dfvfs.lib import errors
from dfvfs.path import hfs_path_spec
from dfvfs.resolver import resolver
from dfvfs.vfs import file_system
from dfvfs.vfs import hfs_file_entry
[docs]
class HFSFileSystem(file_system.FileSystem):
"""File system that uses pyfshfs."""
ROOT_DIRECTORY_IDENTIFIER_NUMBER = 2
TYPE_INDICATOR = definitions.TYPE_INDICATOR_HFS
[docs]
def __init__(self, resolver_context, path_spec):
"""Initializes an HFS file system.
Args:
resolver_context (Context): resolver context.
path_spec (PathSpec): a path specification.
"""
super(HFSFileSystem, self).__init__(resolver_context, path_spec)
self._file_object = None
self._fshfs_volume = None
def _Close(self):
"""Closes the file system.
Raises:
IOError: if the close failed.
"""
self._fshfs_volume = None
self._file_object = None
def _Open(self, mode='rb'):
"""Opens the file system 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 system object could not be opened.
PathSpecError: if the path specification is incorrect.
ValueError: if the path specification is invalid.
"""
if not self._path_spec.HasParent():
raise errors.PathSpecError(
'Unsupported path specification without parent.')
file_object = resolver.Resolver.OpenFileObject(
self._path_spec.parent, resolver_context=self._resolver_context)
fshfs_volume = pyfshfs.volume()
fshfs_volume.open_file_object(file_object)
self._file_object = file_object
self._fshfs_volume = fshfs_volume
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def FileEntryExistsByPathSpec(self, path_spec):
"""Determines if a file entry for a path specification exists.
Args:
path_spec (PathSpec): path specification.
Returns:
bool: True if the file entry exists.
Raises:
BackEndError: if the file entry cannot be opened.
"""
# Opening a file by identifier is faster than opening a file by location.
fshfs_file_entry = None
location = getattr(path_spec, 'location', None)
identifier = getattr(path_spec, 'identifier', None)
try:
if identifier is not None:
fshfs_file_entry = self._fshfs_volume.get_file_entry_by_identifier(
identifier)
elif location is not None:
fshfs_file_entry = self._fshfs_volume.get_file_entry_by_path(location)
except IOError as exception:
raise errors.BackEndError(exception)
return fshfs_file_entry is not None
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def GetFileEntryByPathSpec(self, path_spec):
"""Retrieves a file entry for a path specification.
Args:
path_spec (PathSpec): path specification.
Returns:
HFSFileEntry: file entry or None if not available.
Raises:
BackEndError: if the file entry cannot be opened.
"""
# Opening a file by identifier is faster than opening a file by location.
fshfs_file_entry = None
location = getattr(path_spec, 'location', None)
identifier = getattr(path_spec, 'identifier', None)
if (location == self.LOCATION_ROOT or
identifier == self.ROOT_DIRECTORY_IDENTIFIER_NUMBER):
fshfs_file_entry = self._fshfs_volume.get_root_directory()
return hfs_file_entry.HFSFileEntry(
self._resolver_context, self, path_spec,
fshfs_file_entry=fshfs_file_entry, is_root=True)
try:
if identifier is not None:
fshfs_file_entry = self._fshfs_volume.get_file_entry_by_identifier(
identifier)
elif location is not None:
fshfs_file_entry = self._fshfs_volume.get_file_entry_by_path(location)
except IOError as exception:
raise errors.BackEndError(exception)
if fshfs_file_entry is None:
return None
return hfs_file_entry.HFSFileEntry(
self._resolver_context, self, path_spec,
fshfs_file_entry=fshfs_file_entry)
[docs]
def GetHFSFileEntryByPathSpec(self, path_spec):
"""Retrieves the HFS file entry for a path specification.
Args:
path_spec (PathSpec): a path specification.
Returns:
pyfshfs.file_entry: file entry.
Raises:
PathSpecError: if the path specification is missing location and
identifier.
"""
# Opening a file by identifier is faster than opening a file by location.
location = getattr(path_spec, 'location', None)
identifier = getattr(path_spec, 'identifier', None)
if identifier is not None:
fshfs_file_entry = self._fshfs_volume.get_file_entry_by_identifier(
identifier)
elif location is not None:
fshfs_file_entry = self._fshfs_volume.get_file_entry_by_path(location)
else:
raise errors.PathSpecError(
'Path specification missing location and identifier.')
return fshfs_file_entry
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def GetRootFileEntry(self):
"""Retrieves the root file entry.
Returns:
HFSFileEntry: file entry.
"""
path_spec = hfs_path_spec.HFSPathSpec(
location=self.LOCATION_ROOT,
identifier=self.ROOT_DIRECTORY_IDENTIFIER_NUMBER,
parent=self._path_spec.parent)
return self.GetFileEntryByPathSpec(path_spec)