/usr/share/pyshared/werkzeug/posixemulation.py is in python-werkzeug 0.8.1+dfsg-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 | # -*- coding: utf-8 -*-
r"""
werkzeug.posixemulation
~~~~~~~~~~~~~~~~~~~~~~~
Provides a POSIX emulation for some features that are relevant to
web applications. The main purpose is to simplify support for
systems such as Windows NT that are not 100% POSIX compatible.
Currently this only implements a :func:`rename` function that
follows POSIX semantics. Eg: if the target file already exists it
will be replaced without asking.
This module was introduced in 0.6.1 and is not a public interface.
It might become one in later versions of Werkzeug.
:copyright: (c) 2011 by the Werkzeug Team, see AUTHORS for more details.
:license: BSD, see LICENSE for more details.
"""
import sys
import os
import errno
import time
import random
can_rename_open_file = False
if os.name == 'nt': # pragma: no cover
_rename = lambda src, dst: False
_rename_atomic = lambda src, dst: False
try:
import ctypes
_MOVEFILE_REPLACE_EXISTING = 0x1
_MOVEFILE_WRITE_THROUGH = 0x8
_MoveFileEx = ctypes.windll.kernel32.MoveFileExW
def _rename(src, dst):
if not isinstance(src, unicode):
src = unicode(src, sys.getfilesystemencoding())
if not isinstance(dst, unicode):
dst = unicode(dst, sys.getfilesystemencoding())
if _rename_atomic(src, dst):
return True
retry = 0
rv = False
while not rv and retry < 100:
rv = _MoveFileEx(src, dst, _MOVEFILE_REPLACE_EXISTING |
_MOVEFILE_WRITE_THROUGH)
if not rv:
time.sleep(0.001)
retry += 1
return rv
# new in Vista and Windows Server 2008
_CreateTransaction = ctypes.windll.ktmw32.CreateTransaction
_CommitTransaction = ctypes.windll.ktmw32.CommitTransaction
_MoveFileTransacted = ctypes.windll.kernel32.MoveFileTransactedW
_CloseHandle = ctypes.windll.kernel32.CloseHandle
can_rename_open_file = True
def _rename_atomic(src, dst):
ta = _CreateTransaction(None, 0, 0, 0, 0, 1000, 'Werkzeug rename')
if ta == -1:
return False
try:
retry = 0
rv = False
while not rv and retry < 100:
rv = _MoveFileTransacted(src, dst, None, None,
_MOVEFILE_REPLACE_EXISTING |
_MOVEFILE_WRITE_THROUGH, ta)
if rv:
rv = _CommitTransaction(ta)
break
else:
time.sleep(0.001)
retry += 1
return rv
finally:
_CloseHandle(ta)
except Exception:
pass
def rename(src, dst):
# Try atomic or pseudo-atomic rename
if _rename(src, dst):
return
# Fall back to "move away and replace"
try:
os.rename(src, dst)
except OSError, e:
if e.errno != errno.EEXIST:
raise
old = "%s-%08x" % (dst, random.randint(0, sys.maxint))
os.rename(dst, old)
os.rename(src, dst)
try:
os.unlink(old)
except Exception:
pass
else:
rename = os.rename
can_rename_open_file = True
|