# -*- coding: utf-8 -*-
"""The fake file system implementation."""
from dfvfs.lib import definitions
from dfvfs.lib import errors
from dfvfs.path import fake_path_spec
from dfvfs.vfs import file_system
from dfvfs.vfs import fake_file_entry
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class FakeFileSystem(file_system.FileSystem):
"""Fake file system."""
TYPE_INDICATOR = definitions.TYPE_INDICATOR_FAKE
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def __init__(self, resolver_context, path_spec):
"""Initializes a file system.
Args:
resolver_context (Context): a resolver context.
path_spec (PathSpec): a path specification.
"""
super(FakeFileSystem, self).__init__(resolver_context, path_spec)
self._paths = {}
self.AddFileEntry(
self.LOCATION_ROOT,
file_entry_type=definitions.FILE_ENTRY_TYPE_DIRECTORY)
def _Close(self):
"""Closes the file system.
Raises:
IOError: if the close failed.
"""
return
def _Open(self, mode='rb'):
"""Opens the file system defined by path specification.
Args:
mode (Optional[str]): file access mode. The default is 'rb' which
represents read-only binary.
Raises:
AccessError: if the access to open the file was denied.
IOError: if the file system could not be opened.
PathSpecError: if the path specification is incorrect.
ValueError: if the path specification is invalid.
"""
if self._path_spec.HasParent():
raise errors.PathSpecError(
'Unsupported path specification with parent.')
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def AddFileEntry(
self, path, file_entry_type=definitions.FILE_ENTRY_TYPE_FILE,
file_data=None, link_data=None):
"""Adds a fake file entry.
Args:
path (str): path of the file entry.
file_entry_type (Optional[str]): type of the file entry object.
file_data (Optional[bytes]): data of the fake file-like object.
link_data (Optional[bytes]): link data of the fake file entry object.
Raises:
KeyError: if the path already exists.
ValueError: if the file data is set but the file entry type is not a file
or if the link data is set but the file entry type is not a link.
"""
if path in self._paths:
raise KeyError(f'File entry already set for path: {path:s}.')
if file_data and file_entry_type != definitions.FILE_ENTRY_TYPE_FILE:
raise ValueError('File data set for non-file file entry type.')
if link_data and file_entry_type != definitions.FILE_ENTRY_TYPE_LINK:
raise ValueError('Link data set for non-link file entry type.')
if file_data is not None:
path_data = file_data
elif link_data is not None:
path_data = link_data
else:
path_data = None
self._paths[path] = (file_entry_type, path_data)
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def FileEntryExistsByPath(self, path):
"""Determines if a file entry for a path exists.
Args:
path (str): path of the file entry.
Returns:
bool: True if the file entry exists.
"""
return path and path in self._paths
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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.
"""
location = getattr(path_spec, 'location', None)
return self.FileEntryExistsByPath(location)
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def GetDataByPath(self, path):
"""Retrieves the data associated to a path.
Args:
path (str): path of the file entry.
Returns:
bytes: data or None if not available.
"""
_, path_data = self._paths.get(path, (None, None))
return path_data
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def GetFileEntryByPath(self, path):
"""Retrieves a file entry for a path.
Args:
path (str): path of the file entry.
Returns:
FakeFileEntry: a file entry or None if not available.
"""
if path is None:
return None
file_entry_type, _ = self._paths.get(path, (None, None))
if not file_entry_type:
return None
path_spec = fake_path_spec.FakePathSpec(location=path)
is_root = bool(path == self.LOCATION_ROOT)
return fake_file_entry.FakeFileEntry(
self._resolver_context, self, path_spec,
file_entry_type=file_entry_type, is_root=is_root)
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def GetFileEntryByPathSpec(self, path_spec):
"""Retrieves a file entry for a path specification.
Args:
path_spec (PathSpec): path specification.
Returns:
FakeFileEntry: a file entry or None if not available.
"""
location = getattr(path_spec, 'location', None)
return self.GetFileEntryByPath(location)
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def GetPaths(self):
"""Retrieves the paths dictionary.
Returns:
dict[str, FileIO]: file-like object per path.
"""
return self._paths
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def GetRootFileEntry(self):
"""Retrieves the root file entry.
Returns:
FakeFileEntry: a file entry or None if not available.
"""
path_spec = fake_path_spec.FakePathSpec(location=self.LOCATION_ROOT)
return self.GetFileEntryByPathSpec(path_spec)