Make all classes new-style.

On PyPy, it's documented (http://pypy.org/performance.html#id3) that
old-style classes are slow, and classes that derive from both old and
new are especially slow. I checked with the PyPy devs on IRC today and
they confirmed that's still true with the latest PyPy2 releases.

Unfortunately, FileStorage was one such mixed class, as was Connection.

Moving to new-style classes seems to have a positive impact in the
benchmarks. Here's zodbshootout on PyPy2 5.7.1 against a
FileStorage (running in --threads and with 5 reps to be sure we get
warmed up). First, current ZODB:

"Transaction",                fs
"Add 1000 Objects",            31,738
"Update 1000 Objects",         42,444
"Read 1000 Cold Objects",      51,894
"Read 1000 Hot Objects",       53,187
"Read 1000 Steamin' Objects", 835,877

And with this PR:

"Transaction",                fs
"Add 1000 Objects",             35,651
"Update 1000 Objects",          54,906
"Read 1000 Cold Objects",      103,484
"Read 1000 Hot Objects",        84,721
"Read 1000 Steamin' Objects", 2,112,095

The tests that hit the storage extensively are notably faster, as are
steamin and hot, Connection having been a mixed class.

I ran all tests multiple times. The data files were removed between
runs. There's some variation, but the new-style classes always seem
better.

For comparison, here's CPython 2.7.13:

"Transaction",                fs
"Add 1000 Objects",            19,531
"Update 1000 Objects",         16,201
"Read 1000 Cold Objects",      22,111
"Read 1000 Hot Objects",       21,851
"Read 1000 Steamin' Objects", 880,582

Locally I've run the tests under 2.7 and they all passed.

CHANGES.rst

@@ -5,7 +5,9 @@
 5.2.4 (unreleased)
 ==================
 
-- Nothing changed yet.
+- All classes are new-style classes on Python 2 (they were already
+  new-style on Python 3). This improves performance on PyPy. See
+  `issue 159 <<https://github.com/zopefoundation/ZODB/issues/158>`_.
 
 
 5.2.3 (2017-04-11)

src/ZODB/ActivityMonitor.py

@@ -19,7 +19,7 @@
 from . import utils
 
 
-class ActivityMonitor:
+class ActivityMonitor(object):
     """ZODB load/store activity monitor
 
     This simple implementation just keeps a small log in memory

src/ZODB/ConflictResolution.py

@@ -211,7 +211,7 @@ def klass(self):
         elif isinstance(data, list) and data[0] == 'm':
             return data[1][2]
 
-class PersistentReferenceFactory:
+class PersistentReferenceFactory(object):
 
     data = None
 

src/ZODB/Connection.py

@@ -1120,7 +1120,7 @@ def _prefetch_flatten(self, args):
                         yield ob._p_oid
 
 @implementer(IDataManagerSavepoint)
-class Savepoint:
+class Savepoint(object):
 
     def __init__(self, datamanager, state):
         self.datamanager = datamanager
@@ -1131,7 +1131,7 @@ def rollback(self):
 
 
 @implementer(IBlobStorage)
-class TmpStore:
+class TmpStore(object):
     """A storage-like thing to support savepoints."""
 
 

src/ZODB/DB.py

@@ -1005,7 +1005,7 @@ def open_then_close_db_when_connection_closes(self):
         return conn
 
 
-class ContextManager:
+class ContextManager(object):
     """PEP 343 context manager
     """
 

src/ZODB/ExportImport.py

@@ -29,7 +29,7 @@
 
 logger = logging.getLogger('ZODB.ExportImport')
 
-class ExportImport:
+class ExportImport(object):
 
     def exportFile(self, oid, f=None):
         if f is None:

src/ZODB/FileStorage/FileStorage.py

@@ -2083,7 +2083,7 @@ def __init__(self, oid, tid, data, prev, pos):
         self.pos = pos
 
 
-class UndoSearch:
+class UndoSearch(object):
 
     def __init__(self, file, pos, first, last, filter=None):
         self.file = file
@@ -2144,7 +2144,7 @@ def _readnext(self):
         d.update(e)
         return d
 
-class FilePool:
+class FilePool(object):
 
     closed = False
     writing = False

src/ZODB/FileStorage/fsdump.py

@@ -56,7 +56,7 @@ def fmt(p64):
     # Return a nicely formatted string for a packaged 64-bit value
     return "%016x" % u64(p64)
 
-class Dumper:
+class Dumper(object):
     """A very verbose dumper for debuggin FileStorage problems."""
 
     # TODO:  Should revise this class to use FileStorageFormatter.

src/ZODB/MappingStorage.py

@@ -332,7 +332,7 @@ def tpc_vote(self, transaction):
             raise ZODB.POSException.StorageTransactionError(
                 "tpc_vote called with wrong transaction")
 
-class TransactionRecord:
+class TransactionRecord(object):
 
     status = ' '
 

src/ZODB/UndoLogCompatible.py

@@ -14,7 +14,7 @@
 """Provide backward compatibility with storages that only have undoLog()."""
 
 
-class UndoLogCompatible:
+class UndoLogCompatible(object):
 
     def undoInfo(self, first=0, last=-20, specification=None):
         if specification:

src/ZODB/blob.py

@@ -345,7 +345,7 @@ def log(msg, level=logging.INFO, subsys=_pid, exc_info=False):
     logger.log(level, message, exc_info=exc_info)
 
 
-class FilesystemHelper:
+class FilesystemHelper(object):
     # Storages that implement IBlobStorage can choose to use this
     # helper class to generate and parse blob filenames.  This is not
     # a set-in-stone interface for all filesystem operations dealing
@@ -519,7 +519,7 @@ def listOIDs(self):
             yield oid, path
 
 
-class NoBlobsFileSystemHelper:
+class NoBlobsFileSystemHelper(object):
 
     @property
     def temp_dir(self):

src/ZODB/broken.py

@@ -163,7 +163,7 @@ def find_global(modulename, globalname,
 
        If we "repair" a missing global::
 
-         >>> class ZODBnotthere:
+         >>> class ZODBnotthere(object):
          ...     atall = []
 
          >>> sys.modules['ZODB.not'] = ZODBnotthere
@@ -233,7 +233,7 @@ def rebuild(modulename, globalname, *args):
 
        If we "repair" the brokenness::
 
-         >>> class notthere: # fake notthere module
+         >>> class notthere(object): # fake notthere module
          ...     class atall(object):
          ...         def __new__(self, *args):
          ...             ob = object.__new__(self)

src/ZODB/config.py

@@ -103,7 +103,7 @@ def storageFromURL(url):
 def storageFromConfig(section):
     return section.open()
 
-class BaseConfig:
+class BaseConfig(object):
     """Object representing a configured storage or database.
 
     Methods:

src/ZODB/conversionhack.py

@@ -14,7 +14,7 @@
 
 import persistent.mapping
 
-class fixer:
+class fixer(object):
     def __of__(self, parent):
         def __setstate__(state, self=parent):
             self._container=state
@@ -23,7 +23,7 @@ def __setstate__(state, self=parent):
 
 fixer=fixer()
 
-class hack: pass
+class hack(object): pass
 hack=hack()
 
 def __basicnew__():

src/ZODB/fstools.py

@@ -27,7 +27,7 @@
 from persistent.TimeStamp import TimeStamp
 
 
-class TxnHeader:
+class TxnHeader(object):
     """Object representing a transaction record header.
 
     Attribute   Position  Value
@@ -100,7 +100,7 @@ def prev_txn(self):
         tlen = u64(self._file.read(8))
         return TxnHeader(self._file, self._pos - (tlen + 8))
 
-class DataHeader:
+class DataHeader(object):
     """Object representing a data record header.
 
     Attribute         Position  Value

src/ZODB/scripts/analyze.py

@@ -26,7 +26,7 @@ def FakeUnpickler(f):
     return unpickler
 
 
-class Report:
+class Report(object):
     def __init__(self):
         self.OIDMAP = {}
         self.TYPEMAP = {}

src/ZODB/scripts/fstest.py

@@ -44,7 +44,7 @@
 class FormatError(ValueError):
     """There is a problem with the format of the FileStorage."""
 
-class Status:
+class Status(object):
     checkpoint = b'c'
     undone = b'u'
 

src/ZODB/scripts/migrate.py

@@ -112,7 +112,7 @@ def main():
     except getopt.error as msg:
         error(2, msg)
 
-    class Options:
+    class Options(object):
         stype = 'FileStorage'
         dtype = 'FileStorage'
         verbose = 0
@@ -329,7 +329,7 @@ def doit(srcdb, dstdb, options):
 # helper to deal with differences between old-style store() return and
 # new-style store() return that supports ZEO
 
-class RevidAccumulator:
+class RevidAccumulator(object):
 
     def __init__(self):
         self.data = {}

src/ZODB/scripts/repozo.py

@@ -164,7 +164,7 @@ def parseargs(argv):
     except getopt.error as msg:
         usage(1, msg)
 
-    class Options:
+    class Options(object):
         mode = None         # BACKUP, RECOVER or VERIFY
         file = None         # name of input Data.fs file
         repository = None   # name of directory holding backups

src/ZODB/scripts/tests/test_repozo.py

@@ -38,7 +38,7 @@ def _read_file(name, mode='rb'):
         return f.read()
 
 
-class OurDB:
+class OurDB(object):
 
     _file_name = None
 
@@ -241,7 +241,7 @@ def test_verify_ignored_args(self):
                       sys.stderr.getvalue())
 
 
-class FileopsBase:
+class FileopsBase(object):
 
     def _makeChunks(self):
         from ZODB.scripts.repozo import READCHUNK
@@ -316,7 +316,7 @@ def test_nonempty_read_count(self):
         self.assertEqual(sum, md5(b'x' * 42).hexdigest())
 
 
-class OptionsTestBase:
+class OptionsTestBase(object):
 
     _repository_directory = None
     _data_directory = None
@@ -408,7 +408,7 @@ def test_w_gzipped_files_no_ofp(self):
 
     def test_w_ofp(self):
 
-        class Faux:
+        class Faux(object):
             _closed = False
             def __init__(self):
                 self._written = []

src/ZODB/scripts/zodbload.py

@@ -123,7 +123,7 @@
 import time
 import transaction
 
-class JobProducer:
+class JobProducer(object):
 
     def __init__(self):
         self.jobs = []
@@ -143,7 +143,7 @@ def __nonzero__(self):
 
 
 
-class MBox:
+class MBox(object):
 
     def __init__(self, filename):
         if ' ' in filename:
@@ -247,7 +247,7 @@ def setup(lib_python):
                        PLexicon('lex', '', Splitter(), CaseNormalizer())
                        )
 
-    class extra:
+    class extra(object):
         doc_attr = 'PrincipiaSearchSource'
         lexicon_id = 'lex'
         index_type = 'Okapi BM25 Rank'
@@ -371,7 +371,7 @@ def index(connection, messages, catalog, max):
 
     return message.number
 
-class IndexJob:
+class IndexJob(object):
     needs_mbox = 1
     catalog = 1
     prefix = 'index'
@@ -444,7 +444,7 @@ def edit(connection, mbox, catalog=1):
 
     return norig, ndel, nins
 
-class EditJob:
+class EditJob(object):
     needs_mbox = 1
     prefix = 'edit'
     catalog = 1
@@ -480,7 +480,7 @@ def search(connection, terms, number):
 
     return n
 
-class SearchJob:
+class SearchJob(object):
 
     def __init__(self, terms='', number=10):
 

src/ZODB/serialize.py

@@ -159,7 +159,7 @@ def myhasattr(obj, name, _marker=object()):
     return getattr(obj, name, _marker) is not _marker
 
 
-class ObjectWriter:
+class ObjectWriter(object):
     """Serializes objects for storage in the database.
 
     The ObjectWriter creates object pickles in the ZODB format.  It
@@ -183,7 +183,7 @@ def persistent_id(self, obj):
         """Return the persistent id for obj.
 
         >>> from ZODB.tests.util import P
-        >>> class DummyJar:
+        >>> class DummyJar(object):
         ...     xrefs = True
         ...     def new_oid(self):
         ...         return 42
@@ -192,7 +192,7 @@ def persistent_id(self, obj):
         ...     databases = {}
 
         >>> jar = DummyJar()
-        >>> class O:
+        >>> class O(object):
         ...     _p_jar = jar
         >>> writer = ObjectWriter(O)
 
@@ -260,7 +260,7 @@ def persistent_id(self, obj):
 
         Check that a classic class doesn't get identified improperly:
 
-        >>> class ClassicClara:
+        >>> class ClassicClara(object):
         ...    pass
         >>> clara = ClassicClara()
 
@@ -432,7 +432,7 @@ def _dump(self, classmeta, state):
     def __iter__(self):
         return NewObjectIterator(self._stack)
 
-class NewObjectIterator:
+class NewObjectIterator(object):
 
     # The pickler is used as a forward iterator when the connection
     # is looking for new objects to pickle.
@@ -452,7 +452,7 @@ def __next__(self):
 
     next = __next__
 
-class ObjectReader:
+class ObjectReader(object):
 
     def __init__(self, conn=None, cache=None, factory=None):
         self._conn = conn
@@ -680,7 +680,7 @@ def get_refs(a_pickle):
     u.noload()
 
     # Now we have a list of references.  Need to convert to list of
-    # oids and class info:
+    # oids and class info(object):
 
     result = []
 

src/ZODB/tests/BasicStorage.py

@@ -32,7 +32,7 @@
 
 ZERO = b'\0'*8
 
-class BasicStorage:
+class BasicStorage(object):
     def checkBasics(self):
         self.assertEqual(self._storage.lastTransaction(), ZERO)