Only set mode of new patch if the target file was removed before.
If the file is writable by the user, but owned by a different user, the
chmod will otherwise fail with "Operation not permitted".
Additionally make very sure that the file is only written if either the number
of links is <= 1 or the file was successfully removed.
Maybe this minimal COW code should be replaced by something from util.
import os, stat
def _mode_to_kind(mode):
if stat.S_ISREG(mode): return stat.S_IFREG
if stat.S_ISDIR(mode): return stat.S_IFDIR
if stat.S_ISLNK(mode): return stat.S_IFLNK
if stat.S_ISBLK(mode): return stat.S_IFBLK
if stat.S_ISCHR(mode): return stat.S_IFCHR
if stat.S_ISFIFO(mode): return stat.S_IFIFO
if stat.S_ISSOCK(mode): return stat.S_IFSOCK
return mode
def listdir(path, stat=False):
'''listdir(path, stat=False) -> list_of_tuples
Return a sorted list containing information about the entries
in the directory.
If stat is True, each element is a 3-tuple:
(name, type, stat object)
Otherwise, each element is a 2-tuple:
(name, type)
'''
result = []
prefix = path + os.sep
names = os.listdir(path)
names.sort()
for fn in names:
st = os.lstat(prefix + fn)
if stat:
result.append((fn, _mode_to_kind(st.st_mode), st))
else:
result.append((fn, _mode_to_kind(st.st_mode)))
return result