def fwalk(top=".",
topdown=True,
onerror=None,
*,
follow_symlinks=False,
dir_fd=None):
"""Directory tree generator.
This behaves exactly like walk(), except that it yields a 4-tuple
dirpath, dirnames, filenames, dirfd
`dirpath`, `dirnames` and `filenames` are identical to walk() output,
and `dirfd` is a file descriptor referring to the directory `dirpath`.
The advantage of fwalk() over walk() is that it's safe against symlink
races (when follow_symlinks is False).
If dir_fd is not None, it should be a file descriptor open to a directory,
and top should be relative; top will then be relative to that directory.
(dir_fd is always supported for fwalk.)
Caution:
Since fwalk() yields file descriptors, those are only valid until the
next iteration step, so you should dup() them if you want to keep them
for a longer period.
Example:
import os
for root, dirs, files, rootfd in os.fwalk('python/Lib/email'):
print(root, "consumes", end="")
print(sum([os.stat(name, dir_fd=rootfd).st_size for name in files]),
end="")
print("bytes in", len(files), "non-directory files")
if 'CVS' in dirs:
dirs.remove('CVS') # don't visit CVS directories
"""
if not isinstance(top, int) or not hasattr(top, '__index__'):
top = fspath(top)
# Note: To guard against symlink races, we use the standard
# lstat()/open()/fstat() trick.
orig_st = stat(top, follow_symlinks=False, dir_fd=dir_fd)
topfd = open(top, O_RDONLY, dir_fd=dir_fd)
try:
if (follow_symlinks or (st.S_ISDIR(orig_st.st_mode)
and path.samestat(orig_st, stat(topfd)))):
yield from _fwalk(topfd, top, topdown, onerror,
follow_symlinks)
finally:
close(topfd)
def _fwalk(topfd, toppath, topdown, onerror, follow_symlinks):
# Note: This uses O(depth of the directory tree) file descriptors: if
# necessary, it can be adapted to only require O(1) FDs, see issue
# #13734.
names = listdir(topfd)
dirs, nondirs = [], []
for name in names:
try:
# Here, we don't use AT_SYMLINK_NOFOLLOW to be consistent with
# walk() which reports symlinks to directories as directories.
# We do however check for symlinks before recursing into
# a subdirectory.
if st.S_ISDIR(stat(name, dir_fd=topfd).st_mode):
dirs.append(name)
else:
nondirs.append(name)
except OSError:
try:
# Add dangling symlinks, ignore disappeared files
if st.S_ISLNK(
stat(name, dir_fd=topfd,
follow_symlinks=False).st_mode):
nondirs.append(name)
except OSError:
continue
if topdown:
yield toppath, dirs, nondirs, topfd
for name in dirs:
try:
orig_st = stat(name,
dir_fd=topfd,
follow_symlinks=follow_symlinks)
dirfd = open(name, O_RDONLY, dir_fd=topfd)
except OSError as err:
if onerror is not None:
onerror(err)
continue
try:
if follow_symlinks or path.samestat(orig_st, stat(dirfd)):
dirpath = path.join(toppath, name)
yield from _fwalk(dirfd, dirpath, topdown, onerror,
follow_symlinks)
finally:
close(dirfd)
if not topdown:
yield toppath, dirs, nondirs, topfd
def update_event(self, inp=-1):
self.set_output_val(0, ntpath.samestat(self.input(0), self.input(1)))