mirror of
https://github.com/evilhero/mylar
synced 2024-12-26 09:36:53 +00:00
141 lines
3.7 KiB
Python
Executable file
141 lines
3.7 KiB
Python
Executable file
# portalocker.py - Cross-platform (posix/nt) API for flock-style file locking.
|
|
# Requires python 1.5.2 or better.
|
|
"""Cross-platform (posix/nt) API for flock-style file locking.
|
|
|
|
Synopsis:
|
|
|
|
import portalocker
|
|
file = open("somefile", "r+")
|
|
portalocker.lock(file, portalocker.LOCK_EX)
|
|
file.seek(12)
|
|
file.write("foo")
|
|
file.close()
|
|
|
|
If you know what you're doing, you may choose to
|
|
|
|
portalocker.unlock(file)
|
|
|
|
before closing the file, but why?
|
|
|
|
Methods:
|
|
|
|
lock( file, flags )
|
|
unlock( file )
|
|
|
|
Constants:
|
|
|
|
LOCK_EX
|
|
LOCK_SH
|
|
LOCK_NB
|
|
|
|
Exceptions:
|
|
|
|
LockException
|
|
|
|
Notes:
|
|
|
|
For the 'nt' platform, this module requires the Python Extensions for Windows.
|
|
Be aware that this may not work as expected on Windows 95/98/ME.
|
|
|
|
History:
|
|
|
|
I learned the win32 technique for locking files from sample code
|
|
provided by John Nielsen <nielsenjf@my-deja.com> in the documentation
|
|
that accompanies the win32 modules.
|
|
|
|
Author: Jonathan Feinberg <jdf@pobox.com>,
|
|
Lowell Alleman <lalleman@mfps.com>,
|
|
Rick van Hattem <Rick.van.Hattem@Fawo.nl>
|
|
Version: 0.3
|
|
URL: https://github.com/WoLpH/portalocker
|
|
"""
|
|
|
|
|
|
__all__ = [
|
|
"lock",
|
|
"unlock",
|
|
"LOCK_EX",
|
|
"LOCK_SH",
|
|
"LOCK_NB",
|
|
"LockException",
|
|
]
|
|
|
|
import os
|
|
|
|
class LockException(Exception):
|
|
# Error codes:
|
|
LOCK_FAILED = 1
|
|
|
|
if os.name == 'nt':
|
|
import win32con
|
|
import win32file
|
|
import pywintypes
|
|
LOCK_EX = win32con.LOCKFILE_EXCLUSIVE_LOCK
|
|
LOCK_SH = 0 # the default
|
|
LOCK_NB = win32con.LOCKFILE_FAIL_IMMEDIATELY
|
|
# is there any reason not to reuse the following structure?
|
|
__overlapped = pywintypes.OVERLAPPED()
|
|
elif os.name == 'posix':
|
|
import fcntl
|
|
LOCK_EX = fcntl.LOCK_EX
|
|
LOCK_SH = fcntl.LOCK_SH
|
|
LOCK_NB = fcntl.LOCK_NB
|
|
else:
|
|
raise RuntimeError("PortaLocker only defined for nt and posix platforms")
|
|
|
|
if os.name == 'nt':
|
|
def lock(file, flags):
|
|
hfile = win32file._get_osfhandle(file.fileno())
|
|
try:
|
|
win32file.LockFileEx(hfile, flags, 0, -0x10000, __overlapped)
|
|
except pywintypes.error, exc_value:
|
|
# error: (33, 'LockFileEx', 'The process cannot access the file because another process has locked a portion of the file.')
|
|
if exc_value[0] == 33:
|
|
raise LockException(LockException.LOCK_FAILED, exc_value[2])
|
|
else:
|
|
# Q: Are there exceptions/codes we should be dealing with here?
|
|
raise
|
|
|
|
def unlock(file):
|
|
hfile = win32file._get_osfhandle(file.fileno())
|
|
try:
|
|
win32file.UnlockFileEx(hfile, 0, -0x10000, __overlapped)
|
|
except pywintypes.error, exc_value:
|
|
if exc_value[0] == 158:
|
|
# error: (158, 'UnlockFileEx', 'The segment is already unlocked.')
|
|
# To match the 'posix' implementation, silently ignore this error
|
|
pass
|
|
else:
|
|
# Q: Are there exceptions/codes we should be dealing with here?
|
|
raise
|
|
|
|
elif os.name == 'posix':
|
|
def lock(file, flags):
|
|
try:
|
|
fcntl.flock(file.fileno(), flags)
|
|
except IOError, exc_value:
|
|
# The exception code varies on different systems so we'll catch
|
|
# every IO error
|
|
raise LockException(*exc_value)
|
|
|
|
def unlock(file):
|
|
fcntl.flock(file.fileno(), fcntl.LOCK_UN)
|
|
|
|
|
|
|
|
if __name__ == '__main__':
|
|
from time import time, strftime, localtime
|
|
import sys
|
|
import portalocker
|
|
|
|
log = open('log.txt', "a+")
|
|
portalocker.lock(log, portalocker.LOCK_EX)
|
|
|
|
timestamp = strftime("%m/%d/%Y %H:%M:%S\n", localtime(time()))
|
|
log.write( timestamp )
|
|
|
|
print "Wrote lines. Hit enter to release lock."
|
|
dummy = sys.stdin.readline()
|
|
|
|
log.close()
|
|
|