Created
September 9, 2012 14:34
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##################################################################### | |
# COPY FROM http://www.gnome.org/~jdub/bzr/planet/2.0/planet/htmltmpl.py | |
# and inspired from http://www.python.org/pypi/zc.lockfile | |
# LICENSE: BSD | |
# Modified by: Limodou(limodou@gmail.com) | |
##################################################################### | |
__all__ = ['LOCK_EX', 'LOCK_SH', 'LOCK_UN', 'lock_file', 'unlock_file', | |
'LockFile', 'LockError'] | |
import os | |
class LockError(Exception): | |
"""Couldn't get a lock | |
""" | |
LOCKTYPE_FCNTL = 1 | |
LOCKTYPE_MSVCRT = 2 | |
LOCKTYPE = None | |
try: | |
import fcntl | |
except: | |
try: | |
import msvcrt | |
except: | |
LOCKTYPE = None | |
else: | |
LOCKTYPE = LOCKTYPE_MSVCRT | |
else: | |
LOCKTYPE = LOCKTYPE_FCNTL | |
LOCK_EX = 1 | |
LOCK_SH = 2 | |
LOCK_UN = 3 | |
def lock_file(f, lock=LOCK_SH): | |
try: | |
fd = f.fileno() | |
if LOCKTYPE == LOCKTYPE_FCNTL: | |
if lock == LOCK_SH: | |
fcntl.flock(fd, fcntl.LOCK_SH) | |
elif lock == LOCK_EX: | |
fcntl.flock(fd, fcntl.LOCK_EX) | |
elif lock == LOCK_UN: | |
fcntl.flock(fd, fcntl.LOCK_UN) | |
else: | |
raise LockError, "BUG: bad lock in lock_file" | |
elif LOCKTYPE == LOCKTYPE_MSVCRT: | |
if lock == LOCK_SH: | |
# msvcrt does not support shared locks :-( | |
msvcrt.locking(fd, msvcrt.LK_LOCK, 1) | |
elif lock == LOCK_EX: | |
msvcrt.locking(fd, msvcrt.LK_LOCK, 1) | |
elif lock == LOCK_UN: | |
msvcrt.locking(fd, msvcrt.LK_UNLCK, 1) | |
else: | |
raise LockError, "BUG: bad lock in lock_file" | |
else: | |
raise LockError, "BUG: bad locktype in lock_file" | |
except IOError: | |
raise LockError("Couldn't lock %r" % f.name) | |
def unlock_file(f): | |
lock_file(f, LOCK_UN) | |
class LockFile(object): | |
def __init__(self, lockfilename): | |
self._f = lockfilename | |
self._create_flag = False | |
self._checkfile() | |
def _checkfile(self): | |
if os.path.exists(self._f): | |
self._fd = open(self._f, 'rb') | |
else: | |
dir = os.path.dirname(self._f) | |
if dir and not os.path.exists(dir): | |
os.makedirs(dir) | |
self._fd = open(self._f, 'wb') | |
self._create_flag = True | |
def lock(self, lock_flag=LOCK_SH): | |
lock_file(self._fd, lock_flag) | |
def close(self): | |
unlock_file(self._fd) | |
self._fd.close() | |
def delete(self): | |
self._fd.close() | |
os.unlink(self._f) |
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