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diff --git a/src/mailman/model/messagestore.py b/src/mailman/model/messagestore.py
new file mode 100644
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+++ b/src/mailman/model/messagestore.py
@@ -0,0 +1,137 @@
+# Copyright (C) 2007-2009 by the Free Software Foundation, Inc.
+#
+# This file is part of GNU Mailman.
+#
+# GNU Mailman is free software: you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free
+# Software Foundation, either version 3 of the License, or (at your option)
+# any later version.
+#
+# GNU Mailman is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+# more details.
+#
+# You should have received a copy of the GNU General Public License along with
+# GNU Mailman.  If not, see <http://www.gnu.org/licenses/>.
+
+"""Model for message stores."""
+
+
+from __future__ import absolute_import, unicode_literals
+
+__metaclass__ = type
+__all__ = [
+    'MessageStore',
+    ]
+
+import os
+import errno
+import base64
+import hashlib
+import cPickle as pickle
+
+from zope.interface import implements
+
+from mailman.config import config
+from mailman.interfaces.messages import IMessageStore
+from mailman.model.message import Message
+from mailman.utilities.filesystem import makedirs
+
+
+# It could be very bad if you have already stored files and you change this
+# value.  We'd need a script to reshuffle and resplit.
+MAX_SPLITS = 2
+EMPTYSTRING = ''
+
+
+
+class MessageStore:
+    implements(IMessageStore)
+
+    def add(self, message):
+        # Ensure that the message has the requisite headers.
+        message_ids = message.get_all('message-id', [])
+        if len(message_ids) <> 1:
+            raise ValueError('Exactly one Message-ID header required')
+        # Calculate and insert the X-Message-ID-Hash.
+        message_id = message_ids[0]
+        # Complain if the Message-ID already exists in the storage.
+        existing = config.db.store.find(Message,
+                                        Message.message_id == message_id).one()
+        if existing is not None:
+            raise ValueError(
+                'Message ID already exists in message store: {0}'.format(
+                    message_id))
+        shaobj = hashlib.sha1(message_id)
+        hash32 = base64.b32encode(shaobj.digest())
+        del message['X-Message-ID-Hash']
+        message['X-Message-ID-Hash'] = hash32
+        # Calculate the path on disk where we're going to store this message
+        # object, in pickled format.
+        parts = []
+        split = list(hash32)
+        while split and len(parts) < MAX_SPLITS:
+            parts.append(split.pop(0) + split.pop(0))
+        parts.append(hash32)
+        relpath = os.path.join(*parts)
+        # Store the message in the database.  This relies on the database
+        # providing a unique serial number, but to get this information, we
+        # have to use a straight insert instead of relying on Elixir to create
+        # the object.
+        row = Message(message_id=message_id,
+                      message_id_hash=hash32,
+                      path=relpath)
+        # Now calculate the full file system path.
+        path = os.path.join(config.MESSAGES_DIR, relpath)
+        # Write the file to the path, but catch the appropriate exception in
+        # case the parent directories don't yet exist.  In that case, create
+        # them and try again.
+        while True:
+            try:
+                with open(path, 'w') as fp:
+                    # -1 says to use the highest protocol available.
+                    pickle.dump(message, fp, -1)
+                    break
+            except IOError as error:
+                if error.errno <> errno.ENOENT:
+                    raise
+            makedirs(os.path.dirname(path))
+        return hash32
+
+    def _get_message(self, row):
+        path = os.path.join(config.MESSAGES_DIR, row.path)
+        with open(path) as fp:
+            return pickle.load(fp)
+
+    def get_message_by_id(self, message_id):
+        row = config.db.store.find(Message, message_id=message_id).one()
+        if row is None:
+            return None
+        return self._get_message(row)
+
+    def get_message_by_hash(self, message_id_hash):
+        # It's possible the hash came from a message header, in which case it
+        # will be a Unicode.  However when coming from source code, it may be
+        # an 8-string.  Coerce to the latter if necessary; it must be
+        # US-ASCII.
+        if isinstance(message_id_hash, unicode):
+            message_id_hash = message_id_hash.encode('ascii')
+        row = config.db.store.find(Message,
+                                   message_id_hash=message_id_hash).one()
+        if row is None:
+            return None
+        return self._get_message(row)
+
+    @property
+    def messages(self):
+        for row in config.db.store.find(Message):
+            yield self._get_message(row)
+
+    def delete_message(self, message_id):
+        row = config.db.store.find(Message, message_id=message_id).one()
+        if row is None:
+            raise LookupError(message_id)
+        path = os.path.join(config.MESSAGES_DIR, row.path)
+        os.remove(path)
+        config.db.store.remove(row)