First cut at a rules processor, separate from the disposition of rule hits.

The basic idea is that we process rules on a mlist, message, metadata triplet
making a list of all rules that hit.  Then a different part of the system will
decide on the disposition of a message based on which rules hit and their
priority.

The doctest and plugin architecture is in place, including the tie-in to
setup.py.  Ported the first rule -- emergency.py -- to the new rule
processor.

We no longer need SQLAlchemy as a requirement, and the setuptools/bzr plugin
name has changed.

2 files changed, 79 insertions, 1 deletions

diff --git a/Mailman/interfaces/__init__.py b/Mailman/interfaces/__init__.py
index c4094e365..20dff7fdf 100644
--- a/Mailman/interfaces/__init__.py
+++ b/Mailman/interfaces/__init__.py
@@ -46,7 +46,12 @@ def _populate():
                 is_enum = issubclass(obj, Enum)
             except TypeError:
                 is_enum = False
-            if IInterface.providedBy(obj) or is_enum:
+            is_interface = IInterface.providedBy(obj)
+            try:
+                is_exception = issubclass(obj, Exception)
+            except TypeError:
+                is_exception = False
+            if is_interface or is_exception or is_enum:
                 setattr(iface_mod, name, obj)
                 __all__.append(name)
 
diff --git a/Mailman/interfaces/rule.py b/Mailman/interfaces/rule.py
new file mode 100644
index 000000000..c0cf71697
--- /dev/null
+++ b/Mailman/interfaces/rule.py
@@ -0,0 +1,73 @@
+# Copyright (C) 2007 by the Free Software Foundation, Inc.
+#
+# This program 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 2
+# of the License, or (at your option) any later version.
+#
+# This program 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 this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
+# USA.
+
+"""Interface describing the basics of rules."""
+
+from zope.interface import Interface, Attribute
+
+
+
+class DuplicateRuleError(Exception):
+    """A rule or rule name is added to a processor more than once."""
+
+
+
+class IRule(Interface):
+    """A basic rule."""
+
+    name = Attribute('Rule name; must be unique.')
+    description = Attribute('A brief description of the rule.')
+
+    def check(mlist, msg, msgdata):
+        """Run the rule.
+
+        :param msg: The message object.
+        :param msgdata: The message metadata.
+        :return: A boolean specifying whether the rule was matched or not.
+        """
+
+
+
+class IRuleProcessor(Interface):
+    """A rule processor."""
+
+    def process(mlist, msg, msgdata):
+        """Run all rules this processor knows about.
+
+        :param mlist: The mailing list this message was posted to.
+        :param msg: The message object.
+        :param msgdata: The message metadata.
+        :return: A set of rule names that matched.
+        """
+
+    rules = Attribute('The set of all rules this processor knows about')
+
+    def __getitem__(rule_name):
+        """Return the named rule.
+
+        :param rule_name: The name of the rule.
+        :return: The IRule given by this name.
+        :raise: KeyError if no such rule is known by this processor.
+        """
+
+    def get(rule_name, default=None):
+        """Return the name rule.
+
+        :param rule_name: The name of the rule.
+        :return: The IRule given by this name, or `default` if no such rule
+            is known by this processor.
+        """