Misc: Make @last handle --regexp in a single process for all messages

Spawning one process for each message was a little silly, considering
there can be thousands of messages.

Plus, some instances do reach the timeout after running for a few weeks,
so we really need to fix this.

Ideally, `regexp_wrapper` should also be removed from other plugins
(Todo, Notes, ...) as they have the same issues, but this will do for
now.

plugins/Misc/plugin.py

@@ -1,7 +1,7 @@
 ###
 # Copyright (c) 2002-2005, Jeremiah Fincher
 # Copyright (c) 2009, James McCoy
-# Copyright (c) 2010-2021, Valentin Lorentz
+# Copyright (c) 2010-2022, Valentin Lorentz
 # All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
@@ -34,7 +34,9 @@ import os
 import sys
 import json
 import time
+import queue
 import functools
+import multiprocessing
 
 
 import supybot
@@ -43,6 +45,7 @@ import supybot.conf as conf
 from supybot import commands
 import supybot.utils as utils
 from supybot.commands import *
+from supybot.commands import ProcessTimeoutError
 import supybot.ircdb as ircdb
 import supybot.irclib as irclib
 import supybot.utils.minisix as minisix
@@ -458,6 +461,9 @@ class Misc(callbacks.Plugin):
                                                            msg.channel)
         else:
             skipfirst = False
+
+        final_predicates = []
+
         for (option, arg) in optlist:
             if option == 'from':
                 def f(m, arg=arg):
@@ -482,22 +488,34 @@ class Misc(callbacks.Plugin):
                     return arg.lower() not in m.args[1].lower()
                 predicates.setdefault('without', []).append(f)
             elif option == 'regexp':
-                def f(m, arg=arg):
-                    def f1(s, arg):
-                        """Since we can't enqueue match objects into the multiprocessing queue,
-                        we'll just wrap the function to return bools."""
-                        if process(arg.search, s, timeout=0.1) is not None:
-                            return True
-                        else:
-                            return False
-                    if ircmsgs.isAction(m):
-                        m1 = ircmsgs.unAction(m)
-                    else:
-                        m1 = m.args[1]
-                    return regexp_wrapper(m1, reobj=arg, timeout=0.1,
-                                          plugin_name=self.name(),
-                                          fcn_name='last')
-                predicates.setdefault('regexp', []).append(f)
+                def f(messages, arg=arg):
+                    reobj = re.compile(arg)
+
+                    # using a queue to return results, so we can return at
+                    # least some results in case of timeout
+                    q = multiprocessing.Queue()
+
+                    def p(messages):
+                        for m in messages:
+                            if ircmsgs.isAction(m):
+                                s = ircmsgs.unAction(m)
+                            else:
+                                s = m.args[1]
+                            if reobj.search(s):
+                                q.put(m)
+                    try:
+                        process(p, messages, timeout=3.,
+                                pn=self.name(), cn='last')
+                    except ProcessTimeoutError:
+                        pass
+                    results = []
+                    while True:
+                        try:
+                            results.append(q.get(False))
+                        except queue.Empty:
+                            break
+                    return results
+                final_predicates.append(f)
             elif option == 'nolimit':
                 nolimit = True
         iterable = filter(functools.partial(self._validLastMsg, irc),
@@ -531,24 +549,32 @@ class Misc(callbacks.Plugin):
             showNick = False
         else:
             showNick = True
+
+        candidates = []
+
+        # Run predicates that filter on individual messages
         for m in iterable:
             for predicate in predicates:
-                try:
-                    if not predicate(m):
-                        break
-                except RegexpTimeout:
-                    irc.error(_('The regular expression timed out.'))
-                    return
+                if not predicate(m):
+                    break
             else:
-                if nolimit:
-                    resp.append(ircmsgs.prettyPrint(m,
-                                                    timestampFormat=tsf,
-                                                    showNick=showNick))
-                else:
-                    irc.reply(ircmsgs.prettyPrint(m,
-                                                  timestampFormat=tsf,
-                                                  showNick=showNick))
-                    return
+                candidates.append(m)
+
+        # Run predicates that filter lists of messages
+        for predicate in final_predicates:
+            candidates = predicate(candidates)
+
+        for m in candidates:
+            if nolimit:
+                resp.append(ircmsgs.prettyPrint(m,
+                                                timestampFormat=tsf,
+                                                showNick=showNick))
+            else:
+                irc.reply(ircmsgs.prettyPrint(m,
+                                              timestampFormat=tsf,
+                                              showNick=showNick))
+                return
+
         if not resp:
             irc.error(_('I couldn\'t find a message matching that criteria in '
                       'my history of %s messages.') % len(irc.state.history))