1 files changed, 118 insertions, 0 deletions

diff --git a/src/mailman/core/chains.py b/src/mailman/core/chains.py
new file mode 100644
index 000000000..40b8c779f
--- /dev/null
+++ b/src/mailman/core/chains.py
@@ -0,0 +1,118 @@
+# 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/>.
+
+"""Application support for chain processing."""
+
+from __future__ import absolute_import, unicode_literals
+
+__metaclass__ = type
+__all__ = [
+    'initialize',
+    'process',
+    ]
+
+
+from mailman.chains.accept import AcceptChain
+from mailman.chains.builtin import BuiltInChain
+from mailman.chains.discard import DiscardChain
+from mailman.chains.headers import HeaderMatchChain
+from mailman.chains.hold import HoldChain
+from mailman.chains.reject import RejectChain
+from mailman.config import config
+from mailman.interfaces.chain import LinkAction
+
+
+
+def process(mlist, msg, msgdata, start_chain='built-in'):
+    """Process the message through a chain.
+
+    :param mlist: the IMailingList for this message.
+    :param msg: The Message object.
+    :param msgdata: The message metadata dictionary.
+    :param start_chain: The name of the chain to start the processing with.
+    """
+    # Set up some bookkeeping.
+    chain_stack = []
+    msgdata['rule_hits'] = hits = []
+    msgdata['rule_misses'] = misses = []
+    # Find the starting chain and begin iterating through its links.
+    chain = config.chains[start_chain]
+    chain_iter = chain.get_links(mlist, msg, msgdata)
+    # Loop until we've reached the end of all processing chains.
+    while chain:
+        # Iterate over all links in the chain.  Do this outside a for-loop so
+        # we can capture a chain's link iterator in mid-flight.  This supports
+        # the 'detour' link action
+        try:
+            link = next(chain_iter)
+        except StopIteration:
+            # This chain is exhausted.  Pop the last chain on the stack and
+            # continue iterating through it.  If there's nothing left on the
+            # chain stack then we're completely finished processing.
+            if len(chain_stack) == 0:
+                return
+            chain, chain_iter = chain_stack.pop()
+            continue
+        # Process this link.
+        if link.rule.check(mlist, msg, msgdata):
+            if link.rule.record:
+                hits.append(link.rule.name)
+            # The rule matched so run its action.
+            if link.action is LinkAction.jump:
+                chain = link.chain
+                chain_iter = chain.get_links(mlist, msg, msgdata)
+                continue
+            elif link.action is LinkAction.detour:
+                # Push the current chain so that we can return to it when
+                # the next chain is finished.
+                chain_stack.append((chain, chain_iter))
+                chain = link.chain
+                chain_iter = chain.get_links(mlist, msg, msgdata)
+                continue
+            elif link.action is LinkAction.stop:
+                # Stop all processing.
+                return
+            elif link.action is LinkAction.defer:
+                # Just process the next link in the chain.
+                pass
+            elif link.action is LinkAction.run:
+                link.function(mlist, msg, msgdata)
+            else:
+                raise AssertionError(
+                    'Bad link action: {0}'.format(link.action))
+        else:
+            # The rule did not match; keep going.
+            if link.rule.record:
+                misses.append(link.rule.name)
+
+
+
+def initialize():
+    """Set up chains, both built-in and from the database."""
+    for chain_class in (DiscardChain, HoldChain, RejectChain, AcceptChain):
+        chain = chain_class()
+        assert chain.name not in config.chains, (
+            'Duplicate chain name: {0}'.format(chain.name))
+        config.chains[chain.name] = chain
+    # Set up a couple of other default chains.
+    chain = BuiltInChain()
+    config.chains[chain.name] = chain
+    # Create and initialize the header matching chain.
+    chain = HeaderMatchChain()
+    config.chains[chain.name] = chain
+    # XXX Read chains from the database and initialize them.
+    pass