1 files changed, 146 insertions, 0 deletions
diff --git a/cvs2svn_lib/serializer.py b/cvs2svn_lib/serializer.py
new file mode 100644
index 0000000..24bd81c
--- /dev/null
+++ b/cvs2svn_lib/serializer.py
@@ -0,0 +1,146 @@
+# (Be in -*- python -*- mode.)
+#
+# ====================================================================
+# Copyright (c) 2000-2008 CollabNet.  All rights reserved.
+#
+# This software is licensed as described in the file COPYING, which
+# you should have received as part of this distribution.  The terms
+# are also available at http://subversion.tigris.org/license-1.html.
+# If newer versions of this license are posted there, you may use a
+# newer version instead, at your option.
+#
+# This software consists of voluntary contributions made by many
+# individuals.  For exact contribution history, see the revision
+# history and logs, available at http://cvs2svn.tigris.org/.
+# ====================================================================
+
+"""Picklers and unpicklers that are primed with known objects."""
+
+
+import cStringIO
+import marshal
+import cPickle
+import zlib
+
+
+class Serializer:
+  """An object able to serialize/deserialize some class of objects."""
+
+  def dumpf(self, f, object):
+    """Serialize OBJECT to file-like object F."""
+
+    raise NotImplementedError()
+
+  def dumps(self, object):
+    """Return a string containing OBJECT in serialized form."""
+
+    raise NotImplementedError()
+
+  def loadf(self, f):
+    """Return the next object deserialized from file-like object F."""
+
+    raise NotImplementedError()
+
+  def loads(self, s):
+    """Return the object deserialized from string S."""
+
+    raise NotImplementedError()
+
+
+class MarshalSerializer(Serializer):
+  """This class uses the marshal module to serialize/deserialize.
+
+  This means that it shares the limitations of the marshal module,
+  namely only being able to serialize a few simple python data types
+  without reference loops."""
+
+  def dumpf(self, f, object):
+    marshal.dump(object, f)
+
+  def dumps(self, object):
+    return marshal.dumps(object)
+
+  def loadf(self, f):
+    return marshal.load(f)
+
+  def loads(self, s):
+    return marshal.loads(s)
+
+
+class PrimedPickleSerializer(Serializer):
+  """This class acts as a pickler/unpickler with a pre-initialized memo.
+
+  The picklers and unpicklers are 'pre-trained' to recognize the
+  objects that are in the primer.  If objects are recognized
+  from PRIMER, then only their persistent IDs need to be pickled
+  instead of the whole object.  (Note that the memos needed for
+  pickling and unpickling are different.)
+
+  A new pickler/unpickler is created for each use, each time with the
+  memo initialized appropriately for pickling or unpickling."""
+
+  def __init__(self, primer):
+    """Prepare to make picklers/unpicklers with the specified primer.
+
+    The Pickler and Unpickler are 'primed' by pre-pickling PRIMER,
+    which can be an arbitrary object (e.g., a list of objects that are
+    expected to occur frequently in the objects to be serialized)."""
+
+    f = cStringIO.StringIO()
+    pickler = cPickle.Pickler(f, -1)
+    pickler.dump(primer)
+    self.pickler_memo = pickler.memo
+
+    unpickler = cPickle.Unpickler(cStringIO.StringIO(f.getvalue()))
+    unpickler.load()
+    self.unpickler_memo = unpickler.memo
+
+  def dumpf(self, f, object):
+    """Serialize OBJECT to file-like object F."""
+
+    pickler = cPickle.Pickler(f, -1)
+    pickler.memo = self.pickler_memo.copy()
+    pickler.dump(object)
+
+  def dumps(self, object):
+    """Return a string containing OBJECT in serialized form."""
+
+    f = cStringIO.StringIO()
+    self.dumpf(f, object)
+    return f.getvalue()
+
+  def loadf(self, f):
+    """Return the next object deserialized from file-like object F."""
+
+    unpickler = cPickle.Unpickler(f)
+    unpickler.memo = self.unpickler_memo.copy()
+    return unpickler.load()
+
+  def loads(self, s):
+    """Return the object deserialized from string S."""
+
+    return self.loadf(cStringIO.StringIO(s))
+
+
+class CompressingSerializer(Serializer):
+  """This class wraps other Serializers to compress their serialized data."""
+
+  def __init__(self, wrapee):
+    """Constructor.  WRAPEE is the Serializer whose bitstream ought to be
+    compressed."""
+
+    self.wrapee = wrapee
+
+  def dumpf(self, f, object):
+    marshal.dump(zlib.compress(self.wrapee.dumps(object), 9), f)
+
+  def dumps(self, object):
+    return marshal.dumps(zlib.compress(self.wrapee.dumps(object), 9))
+
+  def loadf(self, f):
+    return self.wrapee.loads(zlib.decompress(marshal.load(f)))
+
+  def loads(self, s):
+    return self.wrapee.loads(zlib.decompress(marshal.loads(s)))
+
+