def getSize(obj):
"""Calculate the size as cheap as possible
"""
# Try the cheap variants first.
# Actually the checks ensure the code never fails but beeing sure
# is better.
try:
# check if to return zero (length is zero)
if len(obj) == 0:
return 0
except:
pass
try:
# check if ``IStreamableReference``
if IStreamableReference.providedBy(obj):
size = obj.getSize()
if size is not None:
return size
except:
pass
try:
# string
if isinstance(obj, types.StringTypes):
return len(obj)
except:
pass
try:
# file like object
methods = dir(obj)
if "seek" in methods and "tell" in methods:
currentPos = obj.tell()
obj.seek(0, 2)
size = obj.tell()
obj.seek(currentPos)
return size
except:
pass
try:
# fallback: pickling the object
stream = StringIO()
p = Pickler(stream, 1)
p.dump(obj)
size = stream.tell()
except:
size = None
return size
def _save(self, history_id, object, referenced_data={}, metadata=None):
histories = self._histories
cloned_referenced_data = {}
for key, ref in referenced_data.items():
# a real storage may treat IStreamableReference obj differently
if IStreamableReference.providedBy(ref):
cloned_referenced_data[key] = deepCopy(ref.getObject())
else:
cloned_referenced_data[key] = deepCopy(ref)
vdata = StorageVersionData(object=deepCopy(object),
referenced_data=cloned_referenced_data,
metadata=metadata)
if history_id in histories.keys():
histories[history_id].append(vdata)
else:
histories[history_id] = [vdata]
return len(histories[history_id]) - 1
def _save(self, history_id, object, referenced_data={}, metadata=None):
histories = self._histories
cloned_referenced_data = {}
for key, ref in referenced_data.items():
# a real storage may treat IStreamableReference obj differently
if IStreamableReference.providedBy(ref):
cloned_referenced_data[key] = deepCopy(ref.getObject())
else:
cloned_referenced_data[key] = deepCopy(ref)
vdata = StorageVersionData(object=deepCopy(object),
referenced_data=cloned_referenced_data,
metadata=metadata)
if history_id in histories.keys():
histories[history_id].append(vdata)
else:
histories[history_id] = [vdata]
return len(histories[history_id]) - 1