Include required antl3 library and check if datastore is available
The datastore is checked for availability before requesting it to
be cleared. This is because gaeftest uses its own method for ensuring
no leakage of data by providing a temporary file as the backend.
Reviewed by: Sverre Rabbelier
"""
Portable file locking utilities.
Based partially on example by Jonathan Feignberg <jdf@pobox.com> in the Python
Cookbook, licensed under the Python Software License.
http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/65203
Example Usage::
>>> from django.core.files import locks
>>> f = open('./file', 'wb')
>>> locks.lock(f, locks.LOCK_EX)
>>> f.write('Django')
>>> f.close()
"""
__all__ = ('LOCK_EX','LOCK_SH','LOCK_NB','lock','unlock')
system_type = None
try:
import win32con
import win32file
import pywintypes
LOCK_EX = win32con.LOCKFILE_EXCLUSIVE_LOCK
LOCK_SH = 0
LOCK_NB = win32con.LOCKFILE_FAIL_IMMEDIATELY
__overlapped = pywintypes.OVERLAPPED()
system_type = 'nt'
except (ImportError, AttributeError):
pass
try:
import fcntl
LOCK_EX = fcntl.LOCK_EX
LOCK_SH = fcntl.LOCK_SH
LOCK_NB = fcntl.LOCK_NB
system_type = 'posix'
except (ImportError, AttributeError):
pass
def fd(f):
"""Get a filedescriptor from something which could be a file or an fd."""
return hasattr(f, 'fileno') and f.fileno() or f
if system_type == 'nt':
def lock(file, flags):
hfile = win32file._get_osfhandle(fd(file))
win32file.LockFileEx(hfile, flags, 0, -0x10000, __overlapped)
def unlock(file):
hfile = win32file._get_osfhandle(fd(file))
win32file.UnlockFileEx(hfile, 0, -0x10000, __overlapped)
elif system_type == 'posix':
def lock(file, flags):
fcntl.lockf(fd(file), flags)
def unlock(file):
fcntl.lockf(fd(file), fcntl.LOCK_UN)
else:
# File locking is not supported.
LOCK_EX = LOCK_SH = LOCK_NB = None
# Dummy functions that don't do anything.
def lock(file, flags):
pass
def unlock(file):
pass