5 files changed, 640 insertions, 0 deletions
diff --git a/mailman/core/chains.py b/mailman/core/chains.py
new file mode 100644
index 000000000..bebbf5bee
--- /dev/null
+++ b/mailman/core/chains.py
@@ -0,0 +1,115 @@
+# Copyright (C) 2007-2008 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."""
+
+__all__ = [
+    'initialize',
+    'process',
+    ]
+__metaclass__ = type
+
+
+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.configuration import config
+from mailman.interfaces 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 = chain_iter.next()
+        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: %s' % 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: %s' % 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
diff --git a/mailman/core/pipelines.py b/mailman/core/pipelines.py
new file mode 100644
index 000000000..c790901b2
--- /dev/null
+++ b/mailman/core/pipelines.py
@@ -0,0 +1,122 @@
+# Copyright (C) 2008 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/>.
+
+"""Pipeline processor."""
+
+__metaclass__ = type
+__all__ = [
+    'initialize',
+    'process',
+    ]
+
+
+from zope.interface import implements
+from zope.interface.verify import verifyObject
+
+from mailman.configuration import config
+from mailman.core.plugins import get_plugins
+from mailman.i18n import _
+from mailman.interfaces import IHandler, IPipeline
+
+
+
+def process(mlist, msg, msgdata, pipeline_name='built-in'):
+    """Process the message through the given pipeline.
+
+    :param mlist: the IMailingList for this message.
+    :param msg: The Message object.
+    :param msgdata: The message metadata dictionary.
+    :param pipeline_name: The name of the pipeline to process through.
+    """
+    pipeline = config.pipelines[pipeline_name]
+    for handler in pipeline:
+        handler.process(mlist, msg, msgdata)
+
+
+
+class BasePipeline:
+    """Base pipeline implementation."""
+
+    implements(IPipeline)
+
+    _default_handlers = ()
+
+    def __init__(self):
+        self._handlers = []
+        for handler_name in self._default_handlers:
+            self._handlers.append(config.handlers[handler_name])
+
+    def __iter__(self):
+        """See `IPipeline`."""
+        for handler in self._handlers:
+            yield handler
+
+
+class BuiltInPipeline(BasePipeline):
+    """The built-in pipeline."""
+
+    name = 'built-in'
+    description = _('The built-in pipeline.')
+
+    _default_handlers = (
+        'mime-delete',
+        'scrubber',
+        'tagger',
+        'calculate-recipients',
+        'avoid-duplicates',
+        'cleanse',
+        'cleanse-dkim',
+        'cook-headers',
+        'to-digest',
+        'to-archive',
+        'to-usenet',
+        'after-delivery',
+        'acknowledge',
+        'to-outgoing',
+        )
+
+
+class VirginPipeline(BasePipeline):
+    """The processing pipeline for virgin messages.
+
+    Virgin messages are those that are crafted internally by Mailman.
+    """
+    name = 'virgin'
+    description = _('The virgin queue pipeline.')
+
+    _default_handlers = (
+        'cook-headers',
+        'to-outgoing',
+        )
+
+
+
+def initialize():
+    """Initialize the pipelines."""
+    # Find all handlers in the registered plugins.
+    for handler_finder in get_plugins('mailman.handlers'):
+        for handler_class in handler_finder():
+            handler = handler_class()
+            verifyObject(IHandler, handler)
+            assert handler.name not in config.handlers, (
+                'Duplicate handler "%s" found in %s' %
+                (handler.name, handler_finder))
+            config.handlers[handler.name] = handler
+    # Set up some pipelines.
+    for pipeline_class in (BuiltInPipeline, VirginPipeline):
+        pipeline = pipeline_class()
+        config.pipelines[pipeline.name] = pipeline
diff --git a/mailman/core/plugins.py b/mailman/core/plugins.py
new file mode 100644
index 000000000..cf22ad377
--- /dev/null
+++ b/mailman/core/plugins.py
@@ -0,0 +1,65 @@
+# Copyright (C) 2007-2008 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/>.
+
+"""Get a requested plugin."""
+
+import pkg_resources
+
+
+
+def get_plugin(group):
+    """Get the named plugin.
+
+    In general, this returns exactly one plugin.  If no plugins have been
+    added to the named group, the 'stock' plugin will be used.  If more than
+    one plugin -- other than the stock one -- exists, an exception will be
+    raised.
+
+    :param group: The plugin group name.
+    :return: The loaded plugin.
+    :raises RuntimeError: If more than one plugin overrides the stock plugin
+        for the named group.
+    """
+    entry_points = list(pkg_resources.iter_entry_points(group))
+    if len(entry_points) == 0:
+        raise RuntimeError('No entry points found for group: %s' % group)
+    elif len(entry_points) == 1:
+        # Okay, this is the one to use.
+        return entry_points[0].load()
+    elif len(entry_points) == 2:
+        # Find the one /not/ named 'stock'.
+        entry_points = [ep for ep in entry_points if ep.name <> 'stock']
+        if len(entry_points) == 0:
+            raise RuntimeError('No stock plugin found for group: %s' % group)
+        elif len(entry_points) == 2:
+            raise RuntimeError('Too many stock plugins defined')
+        else:
+            raise AssertionError('Insanity')
+        return entry_points[0].load()
+    else:
+        raise RuntimeError('Too many plugins for group: %s' % group)
+
+
+
+def get_plugins(group):
+    """Get and return all plugins in the named group.
+
+    :param group: Plugin group name.
+    :return: The loaded plugin.
+    """
+    for entry_point in pkg_resources.iter_entry_points(group):
+        yield entry_point.load()
diff --git a/mailman/core/rules.py b/mailman/core/rules.py
new file mode 100644
index 000000000..2c1e4fb3b
--- /dev/null
+++ b/mailman/core/rules.py
@@ -0,0 +1,44 @@
+# Copyright (C) 2007-2008 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/>.
+
+"""Various rule helpers"""
+
+__metaclass__ = type
+__all__ = [
+    'initialize',
+    ]
+
+
+from zope.interface import implements
+from zope.interface.verify import verifyObject
+
+from mailman.configuration import config
+from mailman.core.plugins import get_plugins
+from mailman.interfaces import IRule
+
+
+
+def initialize():
+    """Find and register all rules in all plugins."""
+    # Find rules in plugins.
+    for rule_finder in get_plugins('mailman.rules'):
+        for rule_class in rule_finder():
+            rule = rule_class()
+            verifyObject(IRule, rule)
+            assert rule.name not in config.rules, (
+                'Duplicate rule "%s" found in %s' % (rule.name, rule_finder))
+            config.rules[rule.name] = rule
diff --git a/mailman/core/styles.py b/mailman/core/styles.py
new file mode 100644
index 000000000..96104c204
--- /dev/null
+++ b/mailman/core/styles.py
@@ -0,0 +1,294 @@
+# Copyright (C) 2007-2008 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 of list styles to new and existing lists."""
+
+__metaclass__ = type
+__all__ = [
+    'DefaultStyle',
+    'style_manager',
+    ]
+
+import datetime
+
+from operator import attrgetter
+from zope.interface import implements
+from zope.interface.verify import verifyObject
+
+from mailman import Utils
+from mailman.configuration import config
+from mailman.core.plugins import get_plugins
+from mailman.i18n import _
+from mailman.interfaces import (
+    Action, DuplicateStyleError, IStyle, IStyleManager, NewsModeration,
+    Personalization)
+
+
+
+class DefaultStyle:
+    """The defalt (i.e. legacy) style."""
+
+    implements(IStyle)
+
+    name = 'default'
+    priority = 0    # the lowest priority style
+
+    def apply(self, mailing_list):
+        """See `IStyle`."""
+        # For cut-n-paste convenience.
+        mlist = mailing_list
+        # Most of these were ripped from the old MailList.InitVars() method.
+        mlist.volume = 1
+        mlist.post_id = 1
+        mlist.new_member_options = config.DEFAULT_NEW_MEMBER_OPTIONS
+        # This stuff is configurable
+        mlist.real_name = mlist.list_name.capitalize()
+        mlist.respond_to_post_requests = True
+        mlist.advertised = config.DEFAULT_LIST_ADVERTISED
+        mlist.max_num_recipients = config.DEFAULT_MAX_NUM_RECIPIENTS
+        mlist.max_message_size = config.DEFAULT_MAX_MESSAGE_SIZE
+        mlist.reply_goes_to_list = config.DEFAULT_REPLY_GOES_TO_LIST
+        mlist.reply_to_address = u''
+        mlist.first_strip_reply_to = config.DEFAULT_FIRST_STRIP_REPLY_TO
+        mlist.admin_immed_notify = config.DEFAULT_ADMIN_IMMED_NOTIFY
+        mlist.admin_notify_mchanges = (
+            config.DEFAULT_ADMIN_NOTIFY_MCHANGES)
+        mlist.require_explicit_destination = (
+            config.DEFAULT_REQUIRE_EXPLICIT_DESTINATION)
+        mlist.acceptable_aliases = config.DEFAULT_ACCEPTABLE_ALIASES
+        mlist.send_reminders = config.DEFAULT_SEND_REMINDERS
+        mlist.send_welcome_msg = config.DEFAULT_SEND_WELCOME_MSG
+        mlist.send_goodbye_msg = config.DEFAULT_SEND_GOODBYE_MSG
+        mlist.bounce_matching_headers = (
+            config.DEFAULT_BOUNCE_MATCHING_HEADERS)
+        mlist.header_matches = []
+        mlist.anonymous_list = config.DEFAULT_ANONYMOUS_LIST
+        mlist.description = u''
+        mlist.info = u''
+        mlist.welcome_msg = u''
+        mlist.goodbye_msg = u''
+        mlist.subscribe_policy = config.DEFAULT_SUBSCRIBE_POLICY
+        mlist.subscribe_auto_approval = config.DEFAULT_SUBSCRIBE_AUTO_APPROVAL
+        mlist.unsubscribe_policy = config.DEFAULT_UNSUBSCRIBE_POLICY
+        mlist.private_roster = config.DEFAULT_PRIVATE_ROSTER
+        mlist.obscure_addresses = config.DEFAULT_OBSCURE_ADDRESSES
+        mlist.admin_member_chunksize = config.DEFAULT_ADMIN_MEMBER_CHUNKSIZE
+        mlist.administrivia = config.DEFAULT_ADMINISTRIVIA
+        mlist.preferred_language = config.DEFAULT_SERVER_LANGUAGE
+        mlist.include_rfc2369_headers = True
+        mlist.include_list_post_header = True
+        mlist.filter_mime_types = config.DEFAULT_FILTER_MIME_TYPES
+        mlist.pass_mime_types = config.DEFAULT_PASS_MIME_TYPES
+        mlist.filter_filename_extensions = (
+            config.DEFAULT_FILTER_FILENAME_EXTENSIONS)
+        mlist.pass_filename_extensions = config.DEFAULT_PASS_FILENAME_EXTENSIONS
+        mlist.filter_content = config.DEFAULT_FILTER_CONTENT
+        mlist.collapse_alternatives = config.DEFAULT_COLLAPSE_ALTERNATIVES
+        mlist.convert_html_to_plaintext = (
+            config.DEFAULT_CONVERT_HTML_TO_PLAINTEXT)
+        mlist.filter_action = config.DEFAULT_FILTER_ACTION
+        # Digest related variables
+        mlist.digestable = config.DEFAULT_DIGESTABLE
+        mlist.digest_is_default = config.DEFAULT_DIGEST_IS_DEFAULT
+        mlist.mime_is_default_digest = config.DEFAULT_MIME_IS_DEFAULT_DIGEST
+        mlist.digest_size_threshhold = config.DEFAULT_DIGEST_SIZE_THRESHHOLD
+        mlist.digest_send_periodic = config.DEFAULT_DIGEST_SEND_PERIODIC
+        mlist.digest_header = config.DEFAULT_DIGEST_HEADER
+        mlist.digest_footer = config.DEFAULT_DIGEST_FOOTER
+        mlist.digest_volume_frequency = config.DEFAULT_DIGEST_VOLUME_FREQUENCY
+        mlist.one_last_digest = {}
+        mlist.digest_members = {}
+        mlist.next_digest_number = 1
+        mlist.nondigestable = config.DEFAULT_NONDIGESTABLE
+        mlist.personalize = Personalization.none
+        # New sender-centric moderation (privacy) options
+        mlist.default_member_moderation = (
+            config.DEFAULT_DEFAULT_MEMBER_MODERATION)
+        # Archiver
+        mlist.archive = config.DEFAULT_ARCHIVE
+        mlist.archive_private = config.DEFAULT_ARCHIVE_PRIVATE
+        mlist.archive_volume_frequency = (
+            config.DEFAULT_ARCHIVE_VOLUME_FREQUENCY)
+        mlist.emergency = False
+        mlist.member_moderation_action = Action.hold
+        mlist.member_moderation_notice = u''
+        mlist.accept_these_nonmembers = []
+        mlist.hold_these_nonmembers = []
+        mlist.reject_these_nonmembers = []
+        mlist.discard_these_nonmembers = []
+        mlist.forward_auto_discards = config.DEFAULT_FORWARD_AUTO_DISCARDS
+        mlist.generic_nonmember_action = (
+            config.DEFAULT_GENERIC_NONMEMBER_ACTION)
+        mlist.nonmember_rejection_notice = u''
+        # Ban lists
+        mlist.ban_list = []
+        # Max autoresponses per day.  A mapping between addresses and a
+        # 2-tuple of the date of the last autoresponse and the number of
+        # autoresponses sent on that date.
+        mlist.hold_and_cmd_autoresponses = {}
+        mlist.subject_prefix = _(config.DEFAULT_SUBJECT_PREFIX)
+        mlist.msg_header = config.DEFAULT_MSG_HEADER
+        mlist.msg_footer = config.DEFAULT_MSG_FOOTER
+        # Set this to Never if the list's preferred language uses us-ascii,
+        # otherwise set it to As Needed
+        if Utils.GetCharSet(mlist.preferred_language) == 'us-ascii':
+            mlist.encode_ascii_prefixes = 0
+        else:
+            mlist.encode_ascii_prefixes = 2
+        # scrub regular delivery
+        mlist.scrub_nondigest = config.DEFAULT_SCRUB_NONDIGEST
+        # automatic discarding
+        mlist.max_days_to_hold = config.DEFAULT_MAX_DAYS_TO_HOLD
+        # Autoresponder
+        mlist.autorespond_postings = False
+        mlist.autorespond_admin = False
+        # this value can be
+        #  0 - no autoresponse on the -request line
+        #  1 - autorespond, but discard the original message
+        #  2 - autorespond, and forward the message on to be processed
+        mlist.autorespond_requests = 0
+        mlist.autoresponse_postings_text = u''
+        mlist.autoresponse_admin_text = u''
+        mlist.autoresponse_request_text = u''
+        mlist.autoresponse_graceperiod = datetime.timedelta(days=90)
+        mlist.postings_responses = {}
+        mlist.admin_responses = {}
+        mlist.request_responses = {}
+        # Bounces
+        mlist.bounce_processing = config.DEFAULT_BOUNCE_PROCESSING
+        mlist.bounce_score_threshold = config.DEFAULT_BOUNCE_SCORE_THRESHOLD
+        mlist.bounce_info_stale_after = config.DEFAULT_BOUNCE_INFO_STALE_AFTER
+        mlist.bounce_you_are_disabled_warnings = (
+            config.DEFAULT_BOUNCE_YOU_ARE_DISABLED_WARNINGS)
+        mlist.bounce_you_are_disabled_warnings_interval = (
+            config.DEFAULT_BOUNCE_YOU_ARE_DISABLED_WARNINGS_INTERVAL)
+        mlist.bounce_unrecognized_goes_to_list_owner = (
+            config.DEFAULT_BOUNCE_UNRECOGNIZED_GOES_TO_LIST_OWNER)
+        mlist.bounce_notify_owner_on_disable = (
+            config.DEFAULT_BOUNCE_NOTIFY_OWNER_ON_DISABLE)
+        mlist.bounce_notify_owner_on_removal = (
+            config.DEFAULT_BOUNCE_NOTIFY_OWNER_ON_REMOVAL)
+        # This holds legacy member related information.  It's keyed by the
+        # member address, and the value is an object containing the bounce
+        # score, the date of the last received bounce, and a count of the
+        # notifications left to send.
+        mlist.bounce_info = {}
+        # New style delivery status
+        mlist.delivery_status = {}
+        # NNTP gateway
+        mlist.nntp_host = config.DEFAULT_NNTP_HOST
+        mlist.linked_newsgroup = u''
+        mlist.gateway_to_news = False
+        mlist.gateway_to_mail = False
+        mlist.news_prefix_subject_too = True
+        # In patch #401270, this was called newsgroup_is_moderated, but the
+        # semantics weren't quite the same.
+        mlist.news_moderation = NewsModeration.none
+        # Topics
+        #
+        # `topics' is a list of 4-tuples of the following form:
+        #
+        #     (name, pattern, description, emptyflag)
+        #
+        # name is a required arbitrary string displayed to the user when they
+        # get to select their topics of interest
+        #
+        # pattern is a required verbose regular expression pattern which is
+        # used as IGNORECASE.
+        #
+        # description is an optional description of what this topic is
+        # supposed to match
+        #
+        # emptyflag is a boolean used internally in the admin interface to
+        # signal whether a topic entry is new or not (new ones which do not
+        # have a name or pattern are not saved when the submit button is
+        # pressed).
+        mlist.topics = []
+        mlist.topics_enabled = False
+        mlist.topics_bodylines_limit = 5
+        # This is a mapping between user "names" (i.e. addresses) and
+        # information about which topics that user is interested in.  The
+        # values are a list of topic names that the user is interested in,
+        # which should match the topic names in mlist.topics above.
+        #
+        # If the user has not selected any topics of interest, then the rule
+        # is that they will get all messages, and they will not have an entry
+        # in this dictionary.
+        mlist.topics_userinterest = {}
+        # The processing chain that messages coming into this list get
+        # processed by.
+        mlist.start_chain = u'built-in'
+        # The default pipeline to send accepted messages through.
+        mlist.pipeline = u'built-in'
+
+    def match(self, mailing_list, styles):
+        """See `IStyle`."""
+        # If no other styles have matched, then the default style matches.
+        if len(styles) == 0:
+            styles.append(self)
+
+
+
+class StyleManager:
+    """The built-in style manager."""
+
+    implements(IStyleManager)
+
+    def __init__(self):
+        """Install all styles from registered plugins, and install them."""
+        self._styles = {}
+        # Install all the styles provided by plugins.
+        for style_factory in get_plugins('mailman.styles'):
+            style = style_factory()
+            # Let DuplicateStyleErrors percolate up.
+            self.register(style)
+
+    def get(self, name):
+        """See `IStyleManager`."""
+        return self._styles.get(name)
+
+    def lookup(self, mailing_list):
+        """See `IStyleManager`."""
+        matched_styles = []
+        for style in self.styles:
+            style.match(mailing_list, matched_styles)
+        for style in matched_styles:
+            yield style
+
+    @property
+    def styles(self):
+        """See `IStyleManager`."""
+        for style in sorted(self._styles.values(),
+                            key=attrgetter('priority'),
+                            reverse=True):
+            yield style
+
+    def register(self, style):
+        """See `IStyleManager`."""
+        verifyObject(IStyle, style)
+        if style.name in self._styles:
+            raise DuplicateStyleError(style.name)
+        self._styles[style.name] = style
+
+    def unregister(self, style):
+        """See `IStyleManager`."""
+        # Let KeyErrors percolate up.
+        del self._styles[style.name]
+
+
+
+style_manager = StyleManager()