//.........这里部分代码省略.........
                    $courses[$courseid] = $course;
                } else {
                    mtrace('Could not find course '.$courseid);
                    unset($posts[$pid]);
                    continue;
                }
            }
            if (!isset($coursemodules[$forumid])) {
                if ($cm = get_coursemodule_from_instance('forum', $forumid, $courseid)) {
                    $coursemodules[$forumid] = $cm;
                } else {
                    mtrace('Could not find course module for forum '.$forumid);
                    unset($posts[$pid]);
                    continue;
                }
            }


            // caching subscribed users of each forum
            if (!isset($subscribedusers[$forumid])) {
                $modcontext = context_module::instance($coursemodules[$forumid]->id);
                if ($subusers = forum_subscribed_users($courses[$courseid], $forums[$forumid], 0, $modcontext, "u.*")) {
                    foreach ($subusers as $postuser) {
                        // this user is subscribed to this forum
                        $subscribedusers[$forumid][$postuser->id] = $postuser->id;
                        $userscount++;
                        if ($userscount > FORUM_CRON_USER_CACHE) {
                            // Store minimal user info.
                            $minuser = new stdClass();
                            $minuser->id = $postuser->id;
                            $users[$postuser->id] = $minuser;
                        } else {
                            // Cache full user record.
                            forum_cron_minimise_user_record($postuser);
                            $users[$postuser->id] = $postuser;
                        }
                    }
                    // Release memory.
                    unset($subusers);
                    unset($postuser);
                }
            }

            $mailcount[$pid] = 0;
            $errorcount[$pid] = 0;
        }
    }

    if ($users && $posts) {

        $urlinfo = parse_url($CFG->wwwroot);
        $hostname = $urlinfo['host'];

        foreach ($users as $userto) {

            @set_time_limit(120); // terminate if processing of any account takes longer than 2 minutes

            mtrace('Processing user '.$userto->id);

            // Init user caches - we keep the cache for one cycle only,
            // otherwise it could consume too much memory.
            if (isset($userto->username)) {
                $userto = clone($userto);
            } else {
                $userto = $DB->get_record('user', array('id' => $userto->id));
                forum_cron_minimise_user_record($userto);

//.........这里部分代码省略.........
                } else {
                    mtrace('Could not find course ' . $courseid);
                    unset($posts[$pid]);
                    continue;
                }
            }
            if (!isset($coursemodules[$forumid])) {
                if ($cm = get_coursemodule_from_instance('forum', $forumid, $courseid)) {
                    $coursemodules[$forumid] = $cm;
                } else {
                    mtrace('Could not find course module for forum ' . $forumid);
                    unset($posts[$pid]);
                    continue;
                }
            }
            // Save the Inbound Message datakey here to reduce DB queries later.
            $messageinboundgenerator->set_data($pid);
            $messageinboundhandlers[$pid] = $messageinboundgenerator->fetch_data_key();
            // Caching subscribed users of each forum.
            if (!isset($subscribedusers[$forumid])) {
                $modcontext = context_module::instance($coursemodules[$forumid]->id);
                if ($subusers = \mod_forum\subscriptions::fetch_subscribed_users($forums[$forumid], 0, $modcontext, 'u.*', true)) {
                    foreach ($subusers as $postuser) {
                        // this user is subscribed to this forum
                        $subscribedusers[$forumid][$postuser->id] = $postuser->id;
                        $userscount++;
                        if ($userscount > FORUM_CRON_USER_CACHE) {
                            // Store minimal user info.
                            $minuser = new stdClass();
                            $minuser->id = $postuser->id;
                            $users[$postuser->id] = $minuser;
                        } else {
                            // Cache full user record.
                            forum_cron_minimise_user_record($postuser);
                            $users[$postuser->id] = $postuser;
                        }
                    }
                    // Release memory.
                    unset($subusers);
                    unset($postuser);
                }
            }
            $mailcount[$pid] = 0;
            $errorcount[$pid] = 0;
        }
    }
    if ($users && $posts) {
        foreach ($users as $userto) {
            // Terminate if processing of any account takes longer than 2 minutes.
            core_php_time_limit::raise(120);
            mtrace('Processing user ' . $userto->id);
            // Init user caches - we keep the cache for one cycle only, otherwise it could consume too much memory.
            if (isset($userto->username)) {
                $userto = clone $userto;
            } else {
                $userto = $DB->get_record('user', array('id' => $userto->id));
                forum_cron_minimise_user_record($userto);
            }
            $userto->viewfullnames = array();
            $userto->canpost = array();
            $userto->markposts = array();
            // Setup this user so that the capabilities are cached, and environment matches receiving user.
            cron_setup_user($userto);
            // Reset the caches.
            foreach ($coursemodules as $forumid => $unused) {
                $coursemodules[$forumid]->cache = new stdClass();