--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/VirtualMailManager/quotalimit.py	Thu Jun 28 19:26:50 2012 +0000
@@ -0,0 +1,126 @@
+# -*- coding: UTF-8 -*-
+# Copyright (c) 2011 - 2012, Pascal Volk
+# See COPYING for distribution information.
+"""
+    VirtualMailManager.quotalimit
+    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+    Virtual Mail Manager's QuotaLimit class to manage quota limits
+    for domains and accounts.
+"""
+
+from VirtualMailManager.pycompat import all
+
+_ = lambda msg: msg
+
+
+class QuotaLimit(object):
+    """Class to handle quota limit specific data."""
+    __slots__ = ('_dbh', '_qid', '_bytes', '_messages')
+    _kwargs = ('qid', 'bytes', 'messages')
+
+    def __init__(self, dbh, **kwargs):
+        """Create a new QuotaLimit instance.
+
+        Either the `qid` keyword or the `bytes` and `messages` keywords
+        must be specified.
+
+        Arguments:
+
+        `dbh` : pyPgSQL.PgSQL.Connection || psycopg2._psycopg.connection
+          A database connection for the database access.
+
+        Keyword arguments:
+
+        `qid` : int
+          The id of a quota limit
+        `bytes` : long
+          The quota limit in bytes.
+        `messages` : int
+          The quota limit in number of messages
+        """
+        self._dbh = dbh
+        self._qid = 0
+        self._bytes = 0
+        self._messages = 0
+
+        for key in kwargs.iterkeys():
+            if key not in self.__class__._kwargs:
+                raise ValueError('unrecognized keyword: %r' % key)
+        qid = kwargs.get('qid')
+        if qid is not None:
+            assert isinstance(qid, (int, long))
+            self._load_by_qid(qid)
+        else:
+            bytes_, msgs = kwargs.get('bytes'), kwargs.get('messages')
+            assert all(isinstance(i, (int, long)) for i in (bytes_, msgs))
+            if bytes_ < 0:
+                self._bytes = -bytes_
+            else:
+                self._bytes = bytes_
+            if msgs < 0:
+                self._messages = -msgs
+            else:
+                self._messages = msgs
+            self._load_by_limit()
+
+    @property
+    def bytes(self):
+        """Quota limit in bytes."""
+        return self._bytes
+
+    @property
+    def messages(self):
+        """Quota limit in number of messages."""
+        return self._messages
+
+    @property
+    def qid(self):
+        """The quota limit's unique ID."""
+        return self._qid
+
+    def __eq__(self, other):
+        if isinstance(other, self.__class__):
+            return self._qid == other._qid
+        return NotImplemented
+
+    def __ne__(self, other):
+        if isinstance(other, self.__class__):
+            return self._qid != other._qid
+        return NotImplemented
+
+    def _load_by_limit(self):
+        """Load the quota limit by limit values from the database."""
+        dbc = self._dbh.cursor()
+        dbc.execute('SELECT qid FROM quotalimit WHERE bytes = %s AND '
+                    'messages = %s', (self._bytes, self._messages))
+        res = dbc.fetchone()
+        dbc.close()
+        if res:
+            self._qid = res[0]
+        else:
+            self._save()
+
+    def _load_by_qid(self, qid):
+        """Load the quota limit by its unique ID from the database."""
+        dbc = self._dbh.cursor()
+        dbc.execute('SELECT bytes, messages FROM quotalimit WHERE qid = %s',
+                    (qid,))
+        res = dbc.fetchone()
+        dbc.close()
+        if not res:
+            raise ValueError('Unknown quota limit id specified: %r' % qid)
+        self._qid = qid
+        self._bytes, self._messages = res
+
+    def _save(self):
+        """Store a new quota limit in the database."""
+        dbc = self._dbh.cursor()
+        dbc.execute("SELECT nextval('quotalimit_id')")
+        self._qid = dbc.fetchone()[0]
+        dbc.execute('INSERT INTO quotalimit (qid, bytes, messages) VALUES '
+                    '(%s, %s, %s)', (self._qid, self._bytes, self._messages))
+        self._dbh.commit()
+        dbc.close()
+
+del _