def dump(this, filename, gzip=False, lock=None, timeout=None):
"""
Writes a python object to a file, using python cPickle
Supports also '~' or '~user'.
@param this: The object, which will be written to disk
@type this: Any python object
@param filename: Filename of the new file
@type filename: String
@param gzip: Use gzip to compress the file
@type gzip: Boolean
@param lock: Use a lockfile to restrict access
"""
## check whether file is locked
## file locked?
filename = os.path.expanduser(filename)
if lock is not None:
lockdir = filename + '.lock'
if timeout is not None and timeout > 0:
end_time = timeout + time.time()
while True:
try:
os.mkdir(lockdir)
except OSError as e:
# File is already locked
if e.errno == errno.EEXIST:
if timeout is not None and time.time() > end_time:
raise IOError("Failed to acquire Lock")
else:
raise IOError("Failed to acquire Lock")
else:
break
if gzip:
import gzip
stream = gzip.GzipFile(filename, 'wb')
else:
stream = open(filename, 'wb')
try:
if type(this).__name__ == 'array':
import Numeric #@UnresolvedImport
p = Numeric.Pickler(stream)
p.dump(this)
else:
Pickle.dump(this, stream, 2)
finally:
stream.close()
if lock is not None:
## release lock
try:
os.rmdir(lockdir)
except:
raise IOError('missing lockfile {0}'.format(lockdir))
