More changes to rules and chains.

Now a link has a rule, action, chain, and function, not all of which needs to
be specified.  The action is a LinkAction enum adn specifies what to do should
the rule match.  The use of the chain or function depends on what the action
is.

Several interface changes now make it easier to jump to other chains, push
(i.e. detour) to chains, etc.  Rules can also now specify that they should not
be recorded in X-* headers.

Added a TruthRule which always matches.

1 files changed, 20 insertions, 0 deletions

diff --git a/Mailman/app/rules.py b/Mailman/app/rules.py
index a3846541e..f0209c767 100644
--- a/Mailman/app/rules.py
+++ b/Mailman/app/rules.py
@@ -18,10 +18,13 @@
 """Various rule helpers"""
 
 __all__ = [
+    'TruthRule',
     'initialize',
     ]
+__metaclass__ = type
 
 
+from zope.interface import implements
 from zope.interface.verify import verifyObject
 
 from Mailman.app.plugins import get_plugins
@@ -30,8 +33,25 @@ from Mailman.interfaces import IRule
 
 
 
+class TruthRule:
+    """A rule that always matches."""
+    implements(IRule)
+
+    name = 'truth'
+    description = 'A rule which always matches.'
+    record = False
+
+    def check(self, mlist, msg, msgdata):
+        """See `IRule`."""
+        return True
+
+
+
 def initialize():
     """Find and register all rules in all plugins."""
+    # Register built in rules.
+    config.rules[TruthRule.name] = TruthRule()
+    # Find rules in plugins.
     for rule_finder in get_plugins('mailman.rules'):
         for rule_class in rule_finder():
             rule = rule_class()