# -*- coding: utf-8 -*-
"""The PHDI image file-like object."""
import pyphdi
from dfvfs.file_io import file_object_io
from dfvfs.lib import errors
from dfvfs.path import factory as path_spec_factory
from dfvfs.resolver import resolver
[docs]
class PHDIFile(file_object_io.FileObjectIO):
"""File input/output (IO) object using pyphdi."""
def _OpenFileObject(self, path_spec):
"""Opens the file-like object defined by path specification.
Args:
path_spec (PathSpec): path specification.
Returns:
pyphdi.handle: a file-like object.
Raises:
IOError: if the file-like object could not be opened.
OSError: if the file-like object could not be opened.
PathSpecError: if the path specification is incorrect.
"""
if not path_spec.HasParent():
raise errors.PathSpecError(
'Unsupported path specification without parent.')
parent_path_spec = path_spec.parent
parent_location = getattr(parent_path_spec, 'location', None)
if not parent_location:
raise errors.PathSpecError(
'Unsupported parent path specification without location.')
# Note that we cannot use pyphdi's open_extent_data_files_as_file_objects
# function since it does not handle the file system abstraction dfVFS
# provides.
file_system = resolver.Resolver.OpenFileSystem(
parent_path_spec, resolver_context=self._resolver_context)
file_object = resolver.Resolver.OpenFileObject(
parent_path_spec, resolver_context=self._resolver_context)
phdi_handle = pyphdi.handle()
phdi_handle.open_file_object(file_object)
parent_location_path_segments = file_system.SplitPath(parent_location)
number_of_image_descriptors = 0
extent_data_files = []
for extent_descriptor in iter(phdi_handle.extent_descriptors):
for image_descriptor in iter(extent_descriptor.image_descriptors):
number_of_image_descriptors += 1
extent_data_filename = image_descriptor.filename
_, path_separator, filename = extent_data_filename.rpartition('/')
if not path_separator:
_, path_separator, filename = extent_data_filename.rpartition('\\')
if not path_separator:
filename = extent_data_filename
# The last parent location path segment contains the extent data
# filename. Since we want to check if the next extent data file exists
# we remove the previous one form the path segments list and add the new
# filename. After that the path segments list can be used to create
# the location string.
parent_location_path_segments.pop()
parent_location_path_segments.append(filename)
extent_data_file_location = file_system.JoinPath(
parent_location_path_segments)
# Note that we don't want to set the keyword arguments when not used
# because the path specification base class will check for unused
# keyword arguments and raise.
kwargs = path_spec_factory.Factory.GetProperties(parent_path_spec)
kwargs['location'] = extent_data_file_location
if parent_path_spec.parent is not None:
kwargs['parent'] = parent_path_spec.parent
extent_data_file_path_spec = path_spec_factory.Factory.NewPathSpec(
parent_path_spec.type_indicator, **kwargs)
if not file_system.FileEntryExistsByPathSpec(
extent_data_file_path_spec):
break
extent_data_files.append(extent_data_file_path_spec)
if len(extent_data_files) != number_of_image_descriptors:
raise IOError('Unable to locate all extent data files.')
file_objects = []
for extent_data_file_path_spec in extent_data_files:
file_object = resolver.Resolver.OpenFileObject(
extent_data_file_path_spec, resolver_context=self._resolver_context)
file_objects.append(file_object)
phdi_handle.open_extent_data_files_as_file_objects(file_objects)
return phdi_handle
[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._file_object.get_media_size()