def lock(self):
"""Lock the file-viewer.
If locked, no one is allowed to run any extraction in `self.src` to
avoid files / directories get messed up.
There is a potential race-condition between getting and setting the
lock.
TODO: This should be re-implemented once we're on Django 1.9+ which
has support for get_or_set.
:return: `True` if the lock was attained,
`False` if there is an already existing lock.
"""
cache_key = self._cache_key(LOCKED)
msg = Message(cache_key)
if msg.get():
# Already locked
yield False
else:
# Not yet locked, save flag and delete on exit.
msg.save(True, time=LOCKED_TIMEOUT)
try:
yield True
finally:
msg.delete()
def test_extract_file_locked_message(self):
self.viewer.src = get_file('dictionary-test.xpi')
assert not self.viewer.is_extracted()
msg = Message(self.viewer._cache_key(LOCKED))
msg.save(True)
msg = extract_file(self.viewer)
assert str(msg.get()).startswith(u'File viewer is locked')
msg.delete()
def test_extract_file_locked_message(self):
self.viewer.src = get_file('dictionary-test.xpi')
assert not self.viewer.is_extracted()
msg = Message(self.viewer._cache_key(LOCKED))
msg.save(True)
msg = extract_file(self.viewer)
assert str(msg.get()).startswith(u'File viewer is locked')
msg.delete()