Assorted filesystem related utility functions, some of which have been bloating cs.fileutils for too long.

Latest release 20220918:

• FSPathBasedSingleton.init: return True on the first call, False on subsequent calls.
• FSPathBasedSingleton.init: probe dict for '_lock' instead of using hasattr (which plays poorly this early on with classes with their own getattr).
• needdir: accept optional log parameter to log mkdir or makedirs.
• HasFSPath: add a default str.

Function atomic_directory(*da, **dkw)

Decorator for a function which fills in a directory which calls the function against a temporary directory then renames the temporary to the target name on completion.

Parameters:

• infill_func: the function to fill in the target directory
• make_placeholder: optional flag, default False: if true an empty directory will be make at the target name and after completion it will be removed and the completed directory renamed to the target name

Function fnmatchdir(dirpath, fnglob)

Return a list of the names in dirpath matching the glob fnglob.

Class FSPathBasedSingleton(cs.obj.SingletonMixin, HasFSPath)

The basis for a SingletonMixin based on realpath(self.fspath).

Method FSPathBasedSingleton.__init__(self, fspath: Optional[str] = None, lock=None): Initialise the singleton:

On the first call:

• set .fspath to self._resolve_fspath(fspath)
• set ._lock to lock (or threading.Lock() if not specified)
• return True On subsequent calls return False.

Class HasFSPath

An object with a .fspath attribute representing a filesystem location.

Function is_clean_subpath(subpath: str)

Test that subpath is clean:

• not empty or '.' or '..'
• not an absolute path
• normalised
• does not walk up out of its parent directory

Examples:

>>> is_clean_subpath('')
False
>>> is_clean_subpath('.')

Function longpath(path, environ=None, prefixes=None)

Return path with prefixes and environment variables substituted. The converse of shortpath().

Function needdir(dirpath, mode=511, *, use_makedirs=False, log=None)

Create the directory dirpath if missing.

Parameters:

• dirpath: the required directory path
• mode: the permissions mode, default 0o777
• log: log makedirs or mkdir call
• use_makedirs: optional creation mode, default False; if true, use os.makedirs, otherwise os.mkdir

Function rpaths(dirpath='.', *, only_suffixes=None, skip_suffixes=None, sort_paths=False)

Yield relative file paths from a directory.

Parameters:

• dirpath: optional top directory, default '.'
• only_suffixes: optional iterable of suffixes of interest; if provided only files ending in these suffixes will be yielded
• skip_suffixes: optional iterable if suffixes to ignore; if provided files ending in these suffixes will not be yielded
• sort_paths: optional flag specifying that filenames should be sorted, default False

Function shortpath(path, environ=None, prefixes=None)

Return path with the first matching leading prefix replaced.

Parameters:

• environ: environment mapping if not os.environ
• prefixes: iterable of (prefix,subst) to consider for replacement; each prefix is subject to environment variable substitution before consideration The default considers "$HOME/" for replacement by "~/".

Release Log

Release 20220918:

• FSPathBasedSingleton.init: return True on the first call, False on subsequent calls.
• FSPathBasedSingleton.init: probe dict for '_lock' instead of using hasattr (which plays poorly this early on with classes with their own getattr).
• needdir: accept optional log parameter to log mkdir or makedirs.
• HasFSPath: add a default str.

Release 20220805: Doc update.

Release 20220530: FSPathBasedSingleton._resolve_fspath: new envvar and default_attr parameters.

Release 20220429:

• New HasFSPath and FSPathBasedSingleton.
• Add longpath and shortpath from cs.fileutils.
• New is_clean_subpath(subpath).
• New needdir(path).
• New fnmatchdir(dirpath,fnglob) pulled out from HasFSPath.fnmatch(fnglob).

Release 20220327: New module cs.fs to contain more filesystem focussed functions than cs.fileutils, which is feeling a bit bloated.