86 lines
2.8 KiB
Python
86 lines
2.8 KiB
Python
"""
|
|
Move a file in the safest way possible::
|
|
|
|
>>> from django.core.files.move import file_move_safe
|
|
>>> file_move_safe("/tmp/old_file", "/tmp/new_file")
|
|
"""
|
|
|
|
import os
|
|
from django.core.files import locks
|
|
|
|
try:
|
|
from shutil import copystat
|
|
except ImportError:
|
|
import stat
|
|
def copystat(src, dst):
|
|
"""Copy all stat info (mode bits, atime and mtime) from src to dst"""
|
|
st = os.stat(src)
|
|
mode = stat.S_IMODE(st.st_mode)
|
|
if hasattr(os, 'utime'):
|
|
os.utime(dst, (st.st_atime, st.st_mtime))
|
|
if hasattr(os, 'chmod'):
|
|
os.chmod(dst, mode)
|
|
|
|
__all__ = ['file_move_safe']
|
|
|
|
def _samefile(src, dst):
|
|
# Macintosh, Unix.
|
|
if hasattr(os.path,'samefile'):
|
|
try:
|
|
return os.path.samefile(src, dst)
|
|
except OSError:
|
|
return False
|
|
|
|
# All other platforms: check for same pathname.
|
|
return (os.path.normcase(os.path.abspath(src)) ==
|
|
os.path.normcase(os.path.abspath(dst)))
|
|
|
|
def file_move_safe(old_file_name, new_file_name, chunk_size = 1024*64, allow_overwrite=False):
|
|
"""
|
|
Moves a file from one location to another in the safest way possible.
|
|
|
|
First, tries ``os.rename``, which is simple but will break across filesystems.
|
|
If that fails, streams manually from one file to another in pure Python.
|
|
|
|
If the destination file exists and ``allow_overwrite`` is ``False``, this
|
|
function will throw an ``IOError``.
|
|
"""
|
|
|
|
# There's no reason to move if we don't have to.
|
|
if _samefile(old_file_name, new_file_name):
|
|
return
|
|
|
|
try:
|
|
os.rename(old_file_name, new_file_name)
|
|
return
|
|
except OSError:
|
|
# This will happen with os.rename if moving to another filesystem
|
|
# or when moving opened files on certain operating systems
|
|
pass
|
|
|
|
# first open the old file, so that it won't go away
|
|
with open(old_file_name, 'rb') as old_file:
|
|
# now open the new file, not forgetting allow_overwrite
|
|
fd = os.open(new_file_name, os.O_WRONLY | os.O_CREAT | getattr(os, 'O_BINARY', 0) |
|
|
(os.O_EXCL if not allow_overwrite else 0))
|
|
try:
|
|
locks.lock(fd, locks.LOCK_EX)
|
|
current_chunk = None
|
|
while current_chunk != b'':
|
|
current_chunk = old_file.read(chunk_size)
|
|
os.write(fd, current_chunk)
|
|
finally:
|
|
locks.unlock(fd)
|
|
os.close(fd)
|
|
copystat(old_file_name, new_file_name)
|
|
|
|
try:
|
|
os.remove(old_file_name)
|
|
except OSError as e:
|
|
# Certain operating systems (Cygwin and Windows)
|
|
# fail when deleting opened files, ignore it. (For the
|
|
# systems where this happens, temporary files will be auto-deleted
|
|
# on close anyway.)
|
|
if getattr(e, 'winerror', 0) != 32 and getattr(e, 'errno', 0) != 13:
|
|
raise
|