def lock(self, blocking=True):
"""
lock the file
:param blocking:
If blocking is True, will block there until cup gets the lock.
True by default.
:return:
return False if locking fails
:raise Exception:
raise cup.err.LockFileError if blocking is False and
the lock action failed
"""
if platforms.is_linux():
flags = 0x1
if FILELOCK_SHARED == self._locktype:
flags = FILELOCK_SHARED
elif FILELOCK_EXCLUSIVE == self._locktype:
flags = FILELOCK_EXCLUSIVE
else:
raise err.LockFileError('does not support this lock type')
if not blocking:
flags |= FILELOCK_NONBLOCKING
ret = None
try:
ret = fcntl.flock(self._fhandle, flags)
except IOError as error:
raise err.LockFileError(error)
except Exception as error:
raise err.LockFileError(error)
return ret
elif platforms.is_windows():
win_lockfile(self._fhandle, blocking)
def unlock(self):
"""unlock the locked file"""
if platforms.is_linux():
try:
fcntl.flock(self._fhandle, FILELOCK_UNLOCK)
except Exception as error:
raise err.LockFileError(error)
elif platforms.is_windows():
win_unlockfile(self._fhandle)
from cup import platforms
__all__ = [
'LockFile', 'FILELOCK_SHARED', 'FILELOCK_EXCLUSIVE',
'FILELOCK_NONBLOCKING', 'FILELOCK_UNLOCK', 'mk_newnode'
]
CANNOT_DEL_PATHLIST = ['/']
if platforms.is_linux() or platforms.is_mac():
import fcntl
FILELOCK_EXCLUSIVE = fcntl.LOCK_EX
FILELOCK_SHARED = fcntl.LOCK_SH
FILELOCK_NONBLOCKING = fcntl.LOCK_NB
FILELOCK_UNLOCK = fcntl.LOCK_UN
elif platforms.is_windows():
import msvcrt
def file_size(fobj):
"""win file size"""
return os.path.getsize(os.path.realpath(fobj.name))
def win_lockfile(fobj, blocking=True):
"""win lock file"""
flags = msvcrt.LK_RLCK
if not blocking:
flags = msvcrt.LK_NBRLCK
msvcrt.locking(fobj.fileno(), flags, file_size(fobj))
def win_unlockfile(fobj):
"""win unlock file"""
