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# Copyright 2012 Pinterest.com
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import logging
from io import BytesIO
import six
from six.moves import cPickle as pickle
try:
long_type = long # noqa
except NameError:
long_type = None
FLAG_BYTES = 0
FLAG_PICKLE = 1 << 0
FLAG_INTEGER = 1 << 1
FLAG_LONG = 1 << 2
FLAG_COMPRESSED = 1 << 3 # unused, to main compatability with python-memcached
FLAG_TEXT = 1 << 4
# Pickle protocol version (-1 for highest available to runtime)
# Warning with `0`: If somewhere in your value lies a slotted object,
# ie defines `__slots__`, even if you do not include it in your pickleable
# state via `__getstate__`, python will complain with something like:
# TypeError: a class that defines __slots__ without defining __getstate__
# cannot be pickled
PICKLE_VERSION = -1
def python_memcache_serializer(key, value):
flags = 0
value_type = type(value)
# Check against exact types so that subclasses of native types will be
# restored as their native type
if value_type is bytes:
pass
elif value_type is six.text_type:
flags |= FLAG_TEXT
value = value.encode('utf8')
elif value_type is int:
flags |= FLAG_INTEGER
value = "%d" % value
elif six.PY2 and value_type is long_type:
flags |= FLAG_LONG
value = "%d" % value
else:
flags |= FLAG_PICKLE
output = BytesIO()
pickler = pickle.Pickler(output, PICKLE_VERSION)
pickler.dump(value)
value = output.getvalue()
return value, flags
def python_memcache_deserializer(key, value, flags):
if flags == 0:
return value
elif flags & FLAG_TEXT:
return value.decode('utf8')
elif flags & FLAG_INTEGER:
return int(value)
elif flags & FLAG_LONG:
if six.PY3:
return int(value)
else:
return long_type(value)
elif flags & FLAG_PICKLE:
try:
buf = BytesIO(value)
unpickler = pickle.Unpickler(buf)
return unpickler.load()
except Exception:
logging.info('Pickle error', exc_info=True)
return None
return value
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