--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/VirtualMailManager/transport.py	Thu Jun 28 19:26:50 2012 +0000
@@ -0,0 +1,100 @@
+# -*- coding: UTF-8 -*-
+# Copyright (c) 2008 - 2012, Pascal Volk
+# See COPYING for distribution information.
+"""
+    VirtualMailManager.transport
+    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+    Virtual Mail Manager's Transport class to manage the transport for
+    domains and accounts.
+"""
+
+from VirtualMailManager.pycompat import any
+
+_ = lambda msg: msg
+
+
+class Transport(object):
+    """A wrapper class that provides access to the transport table"""
+    __slots__ = ('_tid', '_transport', '_dbh')
+
+    def __init__(self, dbh, tid=None, transport=None):
+        """Creates a new Transport instance.
+
+        Either tid or transport must be specified. When both arguments
+        are given, tid will be used.
+
+        Keyword arguments:
+        dbh -- a pyPgSQL.PgSQL.connection
+        tid -- the id of a transport (int/long)
+        transport -- the value of the transport (str)
+
+        """
+        self._dbh = dbh
+        self._tid = 0
+        assert any((tid, transport))
+        if tid:
+            assert not isinstance(tid, bool) and isinstance(tid, (int, long))
+            self._load_by_id(tid)
+        else:
+            assert isinstance(transport, basestring)
+            self._transport = transport
+            self._load_by_name()
+
+    @property
+    def tid(self):
+        """The transport's unique ID."""
+        return self._tid
+
+    @property
+    def transport(self):
+        """The transport's value, ex: 'dovecot:'"""
+        return self._transport
+
+    def __eq__(self, other):
+        if isinstance(other, self.__class__):
+            return self._tid == other._tid
+        return NotImplemented
+
+    def __ne__(self, other):
+        if isinstance(other, self.__class__):
+            return self._tid != other._tid
+        return NotImplemented
+
+    def __str__(self):
+        return self._transport
+
+    def _load_by_id(self, tid):
+        """load a transport by its id from the database"""
+        dbc = self._dbh.cursor()
+        dbc.execute('SELECT transport FROM transport WHERE tid = %s', (tid,))
+        result = dbc.fetchone()
+        dbc.close()
+        if not result:
+            raise ValueError('Unknown transport id specified: %r' % tid)
+        self._transport = result[0]
+        self._tid = tid
+
+    def _load_by_name(self):
+        """Load a transport by its transport name from the database."""
+        dbc = self._dbh.cursor()
+        dbc.execute('SELECT tid FROM transport WHERE transport = %s',
+                    (self._transport,))
+        result = dbc.fetchone()
+        dbc.close()
+        if result:
+            self._tid = result[0]
+        else:
+            self._save()
+
+    def _save(self):
+        """Save the new transport in the database."""
+        dbc = self._dbh.cursor()
+        dbc.execute("SELECT nextval('transport_id')")
+        self._tid = dbc.fetchone()[0]
+        dbc.execute('INSERT INTO transport (tid, transport) VALUES (%s, %s)',
+                    (self._tid, self._transport))
+        self._dbh.commit()
+        dbc.close()
+
+del _