//.........这里部分代码省略.........
                        continue;
                    }
                }

                // Make sure we're allowed to see it...
                if (!forum_user_can_see_post($forum, $discussion, $post, NULL, $cm)) {
                    mtrace('user '.$userto->id. ' can not see '.$post->id);
                    continue;
                }

                // OK so we need to send the email.

                // Does the user want this post in a digest?  If so postpone it for now.
                if ($userto->maildigest > 0) {
                    // This user wants the mails to be in digest form
                    $queue = new stdClass();
                    $queue->userid       = $userto->id;
                    $queue->discussionid = $discussion->id;
                    $queue->postid       = $post->id;
                    $queue->timemodified = $post->created;
                    $DB->insert_record('forum_queue', $queue);
                    continue;
                }


                // Prepare to actually send the post now, and build up the content

                $cleanforumname = str_replace('"', "'", strip_tags(format_string($forum->name)));

                $userfrom->customheaders = array (  // Headers to make emails easier to track
                           'Precedence: Bulk',
                           'List-Id: "'.$cleanforumname.'" <moodleforum'.$forum->id.'@'.$hostname.'>',
                           'List-Help: '.$CFG->wwwroot.'/mod/forum/view.php?f='.$forum->id,
                           'Message-ID: '.forum_get_email_message_id($post->id, $userto->id, $hostname),
                           'X-Course-Id: '.$course->id,
                           'X-Course-Name: '.format_string($course->fullname, true)
                );

                if ($post->parent) {  // This post is a reply, so add headers for threading (see MDL-22551)
                    $userfrom->customheaders[] = 'In-Reply-To: '.forum_get_email_message_id($post->parent, $userto->id, $hostname);
                    $userfrom->customheaders[] = 'References: '.forum_get_email_message_id($post->parent, $userto->id, $hostname);
                }

                $shortname = format_string($course->shortname, true, array('context' => context_course::instance($course->id)));

                $postsubject = html_to_text("$shortname: ".format_string($post->subject, true));
                $posttext = forum_make_mail_text($course, $cm, $forum, $discussion, $post, $userfrom, $userto);
                $posthtml = forum_make_mail_html($course, $cm, $forum, $discussion, $post, $userfrom, $userto);

                // Send the post now!

                mtrace('Sending ', '');

                $eventdata = new stdClass();
                $eventdata->component        = 'mod_forum';
                $eventdata->name             = 'posts';
                $eventdata->userfrom         = $userfrom;
                $eventdata->userto           = $userto;
                $eventdata->subject          = $postsubject;
                $eventdata->fullmessage      = $posttext;
                $eventdata->fullmessageformat = FORMAT_PLAIN;
                $eventdata->fullmessagehtml  = $posthtml;
                $eventdata->notification = 1;

                // If forum_replytouser is not set then send mail using the noreplyaddress.
                if (empty($CFG->forum_replytouser)) {

//.........这里部分代码省略.........
                }
                // Make sure groups allow this user to see this email.
                if ($discussion->groupid > 0 and $groupmode = groups_get_activity_groupmode($cm, $course)) {
                    // Groups are being used.
                    if (!groups_group_exists($discussion->groupid)) {
                        // Can't find group - be safe and don't this message.
                        continue;
                    }
                    if (!groups_is_member($discussion->groupid) and !has_capability('moodle/site:accessallgroups', $modcontext)) {
                        // Do not send posts from other groups when in SEPARATEGROUPS or VISIBLEGROUPS.
                        continue;
                    }
                }
                // Make sure we're allowed to see the post.
                if (!forum_user_can_see_post($forum, $discussion, $post, null, $cm)) {
                    mtrace('User ' . $userto->id . ' can not see ' . $post->id . '. Not sending message.');
                    continue;
                }
                // OK so we need to send the email.
                // Does the user want this post in a digest?  If so postpone it for now.
                $maildigest = forum_get_user_maildigest_bulk($digests, $userto, $forum->id);
                if ($maildigest > 0) {
                    // This user wants the mails to be in digest form.
                    $queue = new stdClass();
                    $queue->userid = $userto->id;
                    $queue->discussionid = $discussion->id;
                    $queue->postid = $post->id;
                    $queue->timemodified = $post->created;
                    $DB->insert_record('forum_queue', $queue);
                    continue;
                }
                // Prepare to actually send the post now, and build up the content.
                $cleanforumname = str_replace('"', "'", strip_tags(format_string($forum->name)));
                $userfrom->customheaders = array('List-Id: "' . $cleanforumname . '" ' . generate_email_messageid('moodleforum' . $forum->id), 'List-Help: ' . $CFG->wwwroot . '/mod/forum/view.php?f=' . $forum->id, 'Message-ID: ' . forum_get_email_message_id($post->id, $userto->id), 'X-Course-Id: ' . $course->id, 'X-Course-Name: ' . format_string($course->fullname, true), 'Precedence: Bulk', 'X-Auto-Response-Suppress: All', 'Auto-Submitted: auto-generated');
                $shortname = format_string($course->shortname, true, array('context' => context_course::instance($course->id)));
                // Generate a reply-to address from using the Inbound Message handler.
                $replyaddress = null;
                if ($userto->canpost[$discussion->id] && array_key_exists($post->id, $messageinboundhandlers)) {
                    $messageinboundgenerator->set_data($post->id, $messageinboundhandlers[$post->id]);
                    $replyaddress = $messageinboundgenerator->generate($userto->id);
                }
                if (!isset($userto->canpost[$discussion->id])) {
                    $canreply = forum_user_can_post($forum, $discussion, $userto, $cm, $course, $modcontext);
                } else {
                    $canreply = $userto->canpost[$discussion->id];
                }
                $data = new \mod_forum\output\forum_post_email($course, $cm, $forum, $discussion, $post, $userfrom, $userto, $canreply);
                $userfrom->customheaders[] = sprintf('List-Unsubscribe: <%s>', $data->get_unsubscribediscussionlink());
                if (!isset($userto->viewfullnames[$forum->id])) {
                    $data->viewfullnames = has_capability('moodle/site:viewfullnames', $modcontext, $userto->id);
                } else {
                    $data->viewfullnames = $userto->viewfullnames[$forum->id];
                }
                // Not all of these variables are used in the default language
                // string but are made available to support custom subjects.
                $a = new stdClass();
                $a->subject = $data->get_subject();
                $a->forumname = $cleanforumname;
                $a->sitefullname = format_string($site->fullname);
                $a->siteshortname = format_string($site->shortname);
                $a->courseidnumber = $data->get_courseidnumber();
                $a->coursefullname = $data->get_coursefullname();
                $a->courseshortname = $data->get_coursename();
                $postsubject = html_to_text(get_string('postmailsubject', 'forum', $a), 0);
                $rootid = forum_get_email_message_id($discussion->firstpost, $userto->id);
                if ($post->parent) {