cs.fs 20240422

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

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

Latest release 20240422: New scandirtree scandir based version of os.walk, yielding (is_dir,fspath). New shim scandirpaths.

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 findup(dirpath: str, criterion: Union[str, Callable[[str], Any]]) -> str

Walk up the filesystem tree looking for a directory where criterion(fspath) is not None, where fspath starts at dirpath. Return the result of criterion(fspath). Return None if no such path is found.

Parameters:

• dirpath: the starting directory
• criterion: a str or a callable accepting a str

If criterion is a str, use look for the existence of os.path.join(fspath,criterion)

Example:

# find a directory containing a `.envrc` file
envrc_path = findup('.', '.envrc')

# find a Tagger rules file for the Downloads directory
rules_path = findup(expanduser('~/Downloads', '.taggerrc')

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

A mixin for an object with a .fspath attribute representing a filesystem location.

The __init__ method just sets the .fspath attribute, and need not be called if the main class takes care of that itself.

Method HasFSPath.fnmatch(self, fnglob): Return a list of the names in self.fspath matching the glob fnglob.

Method HasFSPath.listdir(self): Return os.listdir(self.fspath).

Method HasFSPath.pathto(self, *subpaths): The full path to subpaths, comprising a relative path below self.fspath. This is a shim for os.path.join which requires that all the subpaths be relative paths.

Property HasFSPath.shortpath: The short version of self.fspath.

Function is_valid_rpath(rpath, log=None) -> bool

Test that rpath is a clean relative path with no funny business.

This is a Boolean wrapper for validate_rpath().

Function longpath(path, 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='.', **scan_kw)

A shim for scandirtree to yield relative file paths from a directory.

Parameters:

• dirpath: optional top directory, default '.'

Other keyword arguments are passed to scandirtree.

Function scandirpaths(dirpath='.', **scan_kw)

A shim for scandirtree to yield filesystem paths from a directory.

Parameters:

• dirpath: optional top directory, default '.'

Other keyword arguments are passed to scandirtree.

Function scandirtree(dirpath='.', *, include_dirs=False, name_selector=None, only_suffixes=None, skip_suffixes=None, sort_names=False, follow_symlinks=False, recurse=True)

Generator to recurse over dirpath, yielding (is_dir,subpath) for all selected subpaths.

Parameters:

• dirpath: the directory to scan, default '.'
• include_dirs: if true yield directories; default False
• name_selector: optional callable to select particular names; the default is to select names no starting with a dot ('.')
• only_suffixes: if supplied, skip entries whose extension is not in only_suffixes
• skip_suffixes: if supplied, skip entries whose extension is in skip_suffixes
• sort_names: option flag, default False; yield entires in lexical order if true
• follow_symlinks: optional flag, default False; passed to scandir
• recurse: optional flag, default True; if true, recurse into subdrectories

Function shortpath(path, prefixes=None)

Return path with the first matching leading prefix replaced.

Parameters:

• environ: environment mapping if not os.environ
• prefixes: optional 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 "~/".

Function validate_rpath(rpath: str)

Test that rpath is a clean relative path with no funny business; raise ValueError if the test fails.

Tests:

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

Examples:

>>> validate_rpath('')
False
>>> validate_rpath('.')

Release Log

Release 20240422: New scandirtree scandir based version of os.walk, yielding (is_dir,fspath). New shim scandirpaths.

Release 20240412: HasFSPath: explain that the init is optional in the docstring.

Release 20240316: Fixed release upload artifacts.

Release 20240201:

• FSPathBasedSingleton: drop the default_factory parameter/attribute, let default_attr specify a callable.
• Singleton._resolve_fspath: fix reference to class name.

Release 20231129:

• HasFSPath: new listdir method.
• HasFSPath.pathto: accept multiple relative subpaths.
• FSPathBasedSingleton: accept cls.FSPATH_FACTORY as a factory function for the default fspath, makes it possible to defer the path lookup.
• Replace is_clean_subpath with validate_rpath/is_valid_rpath pair.

Release 20230806:

• Reimplement fnmatchdir using fnmatch.filter.
• No longer claim Python 2 compatibility.

Release 20230401: HasFSPath.shortpath: hand call before .fspath set.

Release 20221221: Replace use of cs.env.envsub with os.path.expandvars and drop unused environ parameter.

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.