class SlfFS(FS):
"""
Implements a read-only file system on top of a SLF-file
"""
_meta = {
'thread_safe': False,
'virtual': False,
'read_only': True,
'unicode_paths': False,
'case_insensitive_paths': False,
'network': False,
'atomic.setcontents': False
}
def __init__(self, slf_filename):
super(SlfFS, self).__init__()
if isinstance(slf_filename, str):
slf_filename = os.path.expanduser(os.path.expandvars(slf_filename))
slf_filename = os.path.normpath(os.path.abspath(slf_filename))
try:
self.file_name = slf_filename
self.file = open(slf_filename, 'rb')
except FileNotFoundError as e:
raise CreateFailedError(
'Slf file not found ({0})'.format(slf_filename),
details=e
)
else:
self.file_name = 'file-like'
self.file = slf_filename
self.header = SlfHeader.from_bytes(self.file.read(SlfHeader.get_size()))
self.entries = list(map(self._read_entry, range(self.header['number_of_entries'])))
self.library_name = self.header['library_name']
self.library_path = self.header['library_path']
self.sort = self.header['sort']
self.version = self.header['version']
self._path_fs = MemoryFS()
for e in self.entries:
path = _get_normalized_filename(e['file_name']).split('/')
directory = '/'.join(path[:-1]) if len(path) > 2 else '/'
if self._path_fs.isfile(directory):
# Sometimes there exists a file that has the same name as a directory
# Solution: Rename it with a _DIRECTORY_CONFLICT suffix
self._path_fs.move(directory, directory + DIRECTORY_CONFLICT_SUFFIX)
if self._path_fs.isdir('/'.join(path)):
self._path_fs.createfile('/'.join(path) + DIRECTORY_CONFLICT_SUFFIX)
else:
self._path_fs.makedir(directory, recursive=True, allow_recreate=True)
self._path_fs.createfile('/'.join(path))
def _read_entry(self, index):
entry_size = SlfEntry.get_size()
self.file.seek(-entry_size * (self.header['number_of_entries'] - index), os.SEEK_END)
return SlfEntry.from_bytes(self.file.read(entry_size))
def __str__(self):
return '<SlfFS: {0}>'.format(self['library_name'])
def isfile(self, path):
return self._path_fs.isfile(path)
def isdir(self, path):
return self._path_fs.isdir(path)
def listdir(self, path="/", wildcard=None, full=False, absolute=False, dirs_only=False, files_only=False):
return self._path_fs.listdir(path, wildcard, full, absolute, dirs_only, files_only)
def open(self, path, mode='r', buffering=-1, encoding='ascii', errors=None, newline=None, line_buffering=False, **kwargs):
if mode != 'r' and mode != 'rb':
raise UnsupportedError(WRITING_NOT_SUPPORTED_ERROR.format('open'))
if not self.exists(path):
raise ResourceNotFoundError(path)
if self.isdir(path):
raise ResourceInvalidError(path)
slf_entry = self._get_slf_entry_for_path(path)
self.file.seek(slf_entry['offset'], os.SEEK_SET)
if mode == 'rb':
return io.BytesIO(self.file.read(slf_entry['length']))
return io.StringIO(self.file.read(slf_entry['length']).decode(encoding))
def getinfo(self, path):
if not self.exists(path):
raise ResourceNotFoundError(path)
if self.isdir(path):
return {
'size': 0
}
slf_entry = self._get_slf_entry_for_path(path)
return {
'size': slf_entry['length'],
'modified_time': slf_entry['time']
}
def makedir(self, path, recursive=False, allow_recreate=False):
raise UnsupportedError(WRITING_NOT_SUPPORTED_ERROR.format('makedir'))
def remove(self, path):
raise UnsupportedError(WRITING_NOT_SUPPORTED_ERROR.format('remove'))
def removedir(self, path, recursive=False, force=False):
raise UnsupportedError(WRITING_NOT_SUPPORTED_ERROR.format('removedir'))
def rename(self, src, dst):
raise UnsupportedError(WRITING_NOT_SUPPORTED_ERROR.format('rename'))
def _get_slf_entry_for_path(self, path):
if path.endswith(DIRECTORY_CONFLICT_SUFFIX):
path = path[:-len(DIRECTORY_CONFLICT_SUFFIX)]
return next(e for e in self.entries if _get_normalized_filename(e['file_name']) == path)
