Python os.supports_fd() Examples

def test_rmtree_uses_safe_fd_version_if_available(self):
        _use_fd_functions = ({os.open, os.stat, os.unlink, os.rmdir} <=
                             os.supports_dir_fd and
                             os.listdir in os.supports_fd and
                             os.stat in os.supports_follow_symlinks)
        if _use_fd_functions:
            self.assertTrue(shutil._use_fd_functions)
            self.assertTrue(shutil.rmtree.avoids_symlink_attacks)
            tmp_dir = self.mkdtemp()
            d = os.path.join(tmp_dir, 'a')
            os.mkdir(d)
            try:
                real_rmtree = shutil._rmtree_safe_fd
                class Called(Exception): pass
                def _raiser(*args, **kwargs):
                    raise Called
                shutil._rmtree_safe_fd = _raiser
                self.assertRaises(Called, shutil.rmtree, d)
            finally:
                shutil._rmtree_safe_fd = real_rmtree
        else:
            self.assertFalse(shutil._use_fd_functions)
            self.assertFalse(shutil.rmtree.avoids_symlink_attacks) 

def test_rmtree_uses_safe_fd_version_if_available(self):
        _use_fd_functions = ({os.open, os.stat, os.unlink, os.rmdir} <=
                             os.supports_dir_fd and
                             os.listdir in os.supports_fd and
                             os.stat in os.supports_follow_symlinks)
        if _use_fd_functions:
            self.assertTrue(shutil._use_fd_functions)
            self.assertTrue(shutil.rmtree.avoids_symlink_attacks)
            tmp_dir = self.mkdtemp()
            d = os.path.join(tmp_dir, 'a')
            os.mkdir(d)
            try:
                real_rmtree = shutil._rmtree_safe_fd
                class Called(Exception): pass
                def _raiser(*args, **kwargs):
                    raise Called
                shutil._rmtree_safe_fd = _raiser
                self.assertRaises(Called, shutil.rmtree, d)
            finally:
                shutil._rmtree_safe_fd = real_rmtree
        else:
            self.assertFalse(shutil._use_fd_functions)
            self.assertFalse(shutil.rmtree.avoids_symlink_attacks) 

def test_rmtree_uses_safe_fd_version_if_available(self):
        _use_fd_functions = ({os.open, os.stat, os.unlink, os.rmdir} <=
                             os.supports_dir_fd and
                             os.listdir in os.supports_fd and
                             os.stat in os.supports_follow_symlinks)
        if _use_fd_functions:
            self.assertTrue(shutil._use_fd_functions)
            self.assertTrue(shutil.rmtree.avoids_symlink_attacks)
            tmp_dir = self.mkdtemp()
            d = os.path.join(tmp_dir, 'a')
            os.mkdir(d)
            try:
                real_rmtree = shutil._rmtree_safe_fd
                class Called(Exception): pass
                def _raiser(*args, **kwargs):
                    raise Called
                shutil._rmtree_safe_fd = _raiser
                self.assertRaises(Called, shutil.rmtree, d)
            finally:
                shutil._rmtree_safe_fd = real_rmtree
        else:
            self.assertFalse(shutil._use_fd_functions)
            self.assertFalse(shutil.rmtree.avoids_symlink_attacks) 

def touch(fname, mode=0o666, dir_fd=None, **kwargs):
    ## After http://stackoverflow.com/questions/1158076/implement-touch-using-python
    if sys.version_info < (3, 3, 0):
        with open(fname, 'a'):
            os.utime(fname, None) # set to now
    else:
        flags = os.O_CREAT | os.O_APPEND
        with os.fdopen(os.open(fname, flags=flags, mode=mode, dir_fd=dir_fd)) as f:
            os.utime(f.fileno() if os.utime in os.supports_fd else fname,
                     dir_fd=None if os.supports_fd else dir_fd, **kwargs) 

def touch(fname, mode=0o666, dir_fd=None, **kwargs):
    """Utility function for updating a file time stamp.

    Source:
        https://stackoverflow.com/questions/1158076/implement-touch-using-python
    """
    flags = os.O_CREAT | os.O_APPEND
    with os.fdopen(os.open(fname, flags=flags, mode=mode, dir_fd=dir_fd)) as f:
        os.utime(f.fileno() if os.utime in os.supports_fd else fname,
                 dir_fd=None if os.supports_fd else dir_fd, **kwargs) 

def touch(fpath, mode=0o666, dir_fd=None, verbose=0, **kwargs):
    """
    change file timestamps

    Works like the touch unix utility

    Args:
        fpath (str | PathLike): name of the file
        mode (int): file permissions (python3 and unix only)
        dir_fd (file): optional directory file descriptor. If specified, fpath
            is interpreted as relative to this descriptor (python 3 only).
        verbose (int): verbosity
        **kwargs : extra args passed to ``os.utime`` (python 3 only).

    Returns:
        str: path to the file

    References:
        https://stackoverflow.com/questions/1158076/implement-touch-using-python

    Example:
        >>> import ubelt as ub
        >>> from os.path import join
        >>> dpath = ub.ensure_app_cache_dir('ubelt')
        >>> fpath = join(dpath, 'touch_file')
        >>> assert not exists(fpath)
        >>> ub.touch(fpath)
        >>> assert exists(fpath)
        >>> os.unlink(fpath)
    """
    if verbose:
        print('Touching file {}'.format(fpath))
    if six.PY2:  # nocover
        with open(fpath, 'a'):
            os.utime(fpath, None)
    else:
        flags = os.O_CREAT | os.O_APPEND
        with os.fdopen(os.open(fpath, flags=flags, mode=mode, dir_fd=dir_fd)) as f:
            os.utime(f.fileno() if os.utime in os.supports_fd else fpath,
                     dir_fd=None if os.supports_fd else dir_fd, **kwargs)
    return fpath 

def touch_file(filename, mode=0o666, times=None, dir_fd=None, ref=None, **kwargs):
    '''update/create a sentinel file.

    modified from: https://stackoverflow.com/questions/1158076/implement-touch-using-python

    Compressed files (ending in .gz) are created as empty 'gzip'
    files, i.e., with a header.

    '''
    flags = os.O_CREAT | os.O_APPEND
    existed = os.path.exists(filename)

    if filename.endswith(".gz") and not existed:
        # this will automatically add a gzip header
        with gzip.GzipFile(filename, "w") as fhandle:
            pass

    if ref:
        stattime = os.stat(ref)
        times = (stattime.st_atime, stattime.st_mtime)

    with os.fdopen(os.open(
            filename, flags=flags, mode=mode, dir_fd=dir_fd)) as fhandle:
        os.utime(
            fhandle.fileno() if os.utime in os.supports_fd else filename,
            dir_fd=None if os.supports_fd else dir_fd,
            **kwargs) 

def touch(fname, mode=0o666, dir_fd=None, **kwargs):
    """
    Implementation of coreutils touch
    http://stackoverflow.com/a/1160227
    """
    flags = os.O_CREAT | os.O_APPEND
    with os.fdopen(os.open(fname, flags=flags, mode=mode, dir_fd=dir_fd)) as f:
        os.utime(f.fileno() if os.utime in os.supports_fd else fname,
                 dir_fd=None if os.supports_fd else dir_fd, **kwargs)