--- dts/framework/serializer.py | 115 ++++++++++++++++++++++++++++++++++++ 1 file changed, 115 insertions(+) create mode 100644 dts/framework/serializer.py
diff --git a/dts/framework/serializer.py b/dts/framework/serializer.py new file mode 100644 index 0000000000..0ffa16a592 --- /dev/null +++ b/dts/framework/serializer.py @@ -0,0 +1,115 @@ +# BSD LICENSE +# +# Copyright(c) 2010-2014 Intel Corporation. All rights reserved. +# All rights reserved. +# +# Redistribution and use in source and binary forms, with or without +# modification, are permitted provided that the following conditions +# are met: +# +# * Redistributions of source code must retain the above copyright +# notice, this list of conditions and the following disclaimer. +# * Redistributions in binary form must reproduce the above copyright +# notice, this list of conditions and the following disclaimer in +# the documentation and/or other materials provided with the +# distribution. +# * Neither the name of Intel Corporation nor the names of its +# contributors may be used to endorse or promote products derived +# from this software without specific prior written permission. +# +# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + +""" +Wrapper class for serializer module +""" +import os +import pickle + + +class Singleton(type): + _instances = {} + + def __call__(self, *args, **kwargs): + if self not in self._instances: + self._instances[self] = super(Singleton, self).__call__(*args, **kwargs) + return self._instances[self] + + +class Serializer(object): + + """ + Two-levels cache implementation for storing/retrieving any kind of object + using using a key-value model. It uses the pickle module to store objects + into a file. + This class implements the Singleton pattern. Everytime its constructor + is called it will return a reference to the same instance. + """ + + def __init__(self): + self.volatile_cache = {} + self.filename = "serializer.cache" + + def save(self, object_name, object_to_save): + """ + Saves an object into the volatile dictionary cache - which + resides in memory. + """ + self.volatile_cache[object_name] = object_to_save + + def load(self, object_name): + """ + Loads and returns an object from the volatile cache. + """ + return self.volatile_cache.get(object_name, None) + + def set_serialized_filename(self, filename): + """ + Sets the name of the non-volatile cache file to be used in the future + """ + self.filename = filename + + def save_to_file(self): + """ + Saves the volatile cache to a file (non-volatile) using the pickle + module. Returns True in case everything went OK, False otherwise. + """ + try: + serialized_file = open(self.filename, "w") + pickle.dump(self.volatile_cache, serialized_file) + serialized_file.close() + return True + except: + return False + + def load_from_file(self): + """ + Reads from a pickle-like file using pickle module and populates the + volatile cache. Returns True in case everything went OK, False + otherwise. + """ + try: + serialized_file = open(self.filename, "r") + self.volatile_cache = pickle.load(serialized_file) + serialized_file.close() + return True + except: + self.volatile_cache.clear() + return False + + def discard_cache(self): + """ + Discards both volatile and non-volatile cache. + """ + self.volatile_cache.clear() + if os.path.exists(self.filename): + os.remove(self.filename) -- 2.20.1