Replace use of sweet_pickle in naming, and delete sweet_pickle subpackage

README.rst

@@ -28,9 +28,6 @@ that is commonly needed by many applications
   listener of selected items in an application.
 - **apptools.scripting**: A framework for automatic recording of Python
   scripts.
-- **apptools.sweet_pickle**: Handles class-level versioning, to support
-  loading of saved data that exist over several generations of internal class
-  structures.
 - **apptools.undo**: Supports undoing and scripting application commands.
 
 Prerequisites

apptools/naming/object_serializer.py

@@ -18,12 +18,10 @@
 import logging
 from traceback import print_exc
 from os.path import splitext
-
-# import cPickle
-# import pickle
+import pickle
 
 # Enthought library imports.
-import apptools.sweet_pickle as sweet_pickle
+from apptools.persistence.versioned_unpickler import VersionedUnpickler
 from traits.api import HasTraits, Str
 
 
@@ -57,9 +55,7 @@ def load(self, path):
         f = open(path, "rb")
         try:
             try:
-                obj = sweet_pickle.load(f)
-            #                obj = cPickle.load(f)
-            #                obj = pickle.load(f)
+                 obj = VersionedUnpickler(f).load()
             except Exception as ex:
                 print_exc()
                 logger.exception(
@@ -89,9 +85,7 @@ def save(self, path, obj):
         # Pickle the object.
         f = open(actual_path, "wb")
         try:
-            sweet_pickle.dump(obj, f, 1)
-        #            cPickle.dump(obj, f, 1)
-        #            pickle.dump(obj, f, 1)
+            pickle.dump(obj, f, 1)
         except Exception as ex:
             logger.exception(
                 "Failed to pickle into file: %s, %s, object:%s"

apptools/naming/tests/test_object_serializer.py

@@ -0,0 +1,52 @@
+# (C) Copyright 2005-2020 Enthought, Inc., Austin, TX
+# All rights reserved.
+#
+# This software is provided without warranty under the terms of the BSD
+# license included in LICENSE.txt and may be redistributed only under
+# the conditions described in the aforementioned license. The license
+# is also available online at http://www.enthought.com/licenses/BSD.txt
+#
+# Thanks for using Enthought open source!
+import os
+import shutil
+import tempfile
+import unittest
+
+from traits.api import cached_property, HasTraits, Property, Str, Event
+
+from apptools.naming.api import ObjectSerializer
+
+
+class FooWithTraits(HasTraits):
+    """Dummy HasTraits class for testing ObjectSerizalizer."""
+
+    full_name = Str()
+
+    last_name = Property(depends_on="full_name")
+
+    event = Event()
+
+    @cached_property
+    def _get_last_name(self):
+        return self.full_name.split(" ")[-1]
+
+class TestObjectSerializer(unittest.TestCase):
+
+    def setUp(self):
+        self.tmpdir = tempfile.mkdtemp()
+        self.addCleanup(shutil.rmtree, self.tmpdir)
+        self.tmp_file = os.path.join(self.tmpdir, "tmp.pickle")
+
+    def test_save_load_roundtrip(self):
+        # Test HasTraits objects can be serialized and deserialized as expected
+        obj = FooWithTraits(full_name="John Doe")
+
+        serializer = ObjectSerializer()
+        serializer.save(self.tmp_file, obj)
+
+        self.assertTrue(serializer.can_load(self.tmp_file))
+        deserialized = serializer.load(self.tmp_file)
+
+        self.assertIsInstance(deserialized, FooWithTraits)
+        self.assertEqual(deserialized.full_name, "John Doe")
+        self.assertEqual(deserialized.last_name, "Doe")

apptools/persistence/tests/test_class_mapping.py

@@ -0,0 +1,79 @@
+# -----------------------------------------------------------------------------
+#
+#  Copyright (c) 2006 by Enthought, Inc.
+#  All rights reserved.
+#
+#  Author: Dave Peterson <dpeterson@enthought.com>
+#
+# -----------------------------------------------------------------------------
+
+""" Tests the class mapping functionality of the enthought.pickle
+    framework.
+"""
+
+# Standard library imports.
+import io
+import pickle
+import unittest
+
+# Enthought library imports
+from apptools.persistence.versioned_unpickler import VersionedUnpickler
+from apptools.persistence.updater import Updater
+
+
+##############################################################################
+# Classes to use within the tests
+##############################################################################
+
+
+class Foo:
+    pass
+
+
+class Bar:
+    pass
+
+
+class Baz:
+    pass
+
+
+##############################################################################
+# class 'ClassMappingTestCase'
+##############################################################################
+
+
+class ClassMappingTestCase(unittest.TestCase):
+    """Tests the class mapping functionality of the apptools.sweet_pickle
+    framework.
+    """
+
+    ##########################################################################
+    # 'TestCase' interface
+    ##########################################################################
+
+    ### public interface #####################################################
+
+    def test_unpickled_class_mapping(self):
+
+        class TestUpdater(Updater):
+            def __init__(self):
+                self.refactorings = {
+                    (Foo.__module__, Foo.__name__): (Bar.__module__, Bar.__name__),
+                    (Bar.__module__, Bar.__name__): (Baz.__module__, Baz.__name__),
+                }
+                self.setstates = {}
+
+        # Validate that unpickling the first class gives us an instance of
+        # the second class.
+        start = Foo()
+        test_file = io.BytesIO(pickle.dumps(start, 2))
+        end = VersionedUnpickler(test_file, updater=TestUpdater()).load()
+        self.assertIsInstance(end, Bar)
+
+        # Validate that unpickling the second class gives us an instance of
+        # the third class.
+        start = Bar()
+        test_file = io.BytesIO(pickle.dumps(start, 2))
+        end = VersionedUnpickler(test_file, updater=TestUpdater()).load()
+        self.assertIsInstance(end, Baz)

apptools/sweet_pickle/tests/test_two_stage_unpickler.py → apptools/persistence/tests/test_two_stage_unpickler.py

@@ -7,17 +7,22 @@
 #          Prabhu Ramachandran <prabhu@aero.iitb.ac.in>
 # -----------------------------------------------------------------------------
 
-# Test cases.
-from __future__ import print_function
+""" This was previously a test for the now deleted apptools.sweet_pickle
+sub package.  It is included here to showcase how apptools.persistance can be
+used to replace sweet_pickle functionality.
+"""
 
+import io
 import random
+import re
 import pickle
 import unittest
 
-import apptools.sweet_pickle as sweet_pickle
+from apptools.persistence.versioned_unpickler import VersionedUnpickler
 
 ########################################
 
+
 # Usecase1: generic case
 class A(object):
     def __init__(self, b=None):
@@ -66,8 +71,6 @@ def __initialize__(self):
 
 class GenericTestCase(unittest.TestCase):
     def test_generic(self):
-        print("\nRunning generic test...")
-
         a = A()
         b = B()
         a.x = random.randint(1, 100)
@@ -79,24 +82,19 @@ def test_generic(self):
         s = pickle.dumps(a)
         new_a = pickle.loads(s)
         try:
-            print("\ta.x: %s" % new_a.x)
-            print("\ta.b_ref.y: %s" % new_a.b_ref.y)
-        except Exception as msg:
-            print("\t%s" % "Expected Error".center(75, "*"))
-            print("\t%s" % msg)
-            print("\t%s" % ("*" * 75))
+            new_a.x
+            new_a.b_ref.y
+        except Exception:
+            pass
 
         # This will work!
         s = pickle.dumps(a)
-        new_a = sweet_pickle.loads(s)
+        new_a = VersionedUnpickler(io.BytesIO(s)).load()
         assert new_a.x == new_a.b_ref.y == value
 
-        print("Generic test succesfull.\n\n")
-
 
 ########################################
 # Usecase2: Toy Application
-import re
 
 
 class StringFinder(object):
@@ -154,14 +152,11 @@ def __init__(self):
         self.finder = StringFinder(self.reader, "e")
 
     def get(self):
-        print("\t%s" % self.finder.data)
-        print("\t%s" % self.reader.data)
+        pass
 
 
 class ToyAppTestCase(unittest.TestCase):
     def test_toy_app(self):
-        print("\nRunning toy app test...")
-
         a = Application()
         a.finder.find()
         a.get()
@@ -170,19 +165,9 @@ def test_toy_app(self):
         # Won't work.
         try:
             b.get()
-        except Exception as msg:
-            print("\t%s" % "Expected Error".center(75, "*"))
-            print("\t%s" % msg)
-            print("\t%s" % ("*" * 75))
+        except Exception:
+            pass
 
         # Works fine.
-        c = sweet_pickle.loads(s)
+        c = VersionedUnpickler(io.BytesIO(s)).load()
         c.get()
-
-        print("Toy app test succesfull.\n\n")
-
-
-if __name__ == "__main__":
-    test_generic()
-    test_toy_app()
-    print("ALL TESTS SUCCESFULL\n")

apptools/persistence/versioned_unpickler.py

@@ -1,5 +1,6 @@
 # Standard library imports
-from pickle import BUILD, Unpickler, UnpicklingError
+from pickle import _Unpickler as Unpickler
+from pickle import UnpicklingError, BUILD
 import logging
 from types import GeneratorType