function useredit_update_bounces($user, $usernew)
{
    if (!isset($usernew->email)) {
        //locked field
        return;
    }
    if (!isset($user->email) || $user->email !== $usernew->email) {
        set_bounce_count($usernew, true);
        set_send_count($usernew, true);
    }
}

//.........这里部分代码省略.........
            // If no html has been given, BUT there is an html wrapping template then
            // auto convert the text to html and then wrap it.
            $autohtml = trim(text_to_html($messagetext));
            $context['body'] = $autohtml;
            $temphtml = $renderer->render_from_template('core/email_html', $context);
            if ($autohtml != $temphtml) {
                $messagehtml = $temphtml;
            }
        }
    }
    $context['body'] = $messagetext;
    $mail->Subject = $renderer->render_from_template('core/email_subject', $context);
    $mail->FromName = $renderer->render_from_template('core/email_fromname', $context);
    $messagetext = $renderer->render_from_template('core/email_text', $context);
    // Autogenerate a MessageID if it's missing.
    if (empty($mail->MessageID)) {
        $mail->MessageID = generate_email_messageid();
    }
    if ($messagehtml && !empty($user->mailformat) && $user->mailformat == 1) {
        // Don't ever send HTML to users who don't want it.
        $mail->isHTML(true);
        $mail->Encoding = 'quoted-printable';
        $mail->Body = $messagehtml;
        $mail->AltBody = "\n{$messagetext}\n";
    } else {
        $mail->IsHTML(false);
        $mail->Body = "\n{$messagetext}\n";
    }
    if ($attachment && $attachname) {
        if (preg_match("~\\.\\.~", $attachment)) {
            // Security check for ".." in dir path.
            $temprecipients[] = array($supportuser->email, fullname($supportuser, true));
            $mail->addStringAttachment('Error in attachment.  User attempted to attach a filename with a unsafe name.', 'error.txt', '8bit', 'text/plain');
        } else {
            require_once $CFG->libdir . '/filelib.php';
            $mimetype = mimeinfo('type', $attachname);
            $attachmentpath = $attachment;
            // Before doing the comparison, make sure that the paths are correct (Windows uses slashes in the other direction).
            $attachpath = str_replace('\\', '/', $attachmentpath);
            // Make sure both variables are normalised before comparing.
            $temppath = str_replace('\\', '/', realpath($CFG->tempdir));
            // If the attachment is a full path to a file in the tempdir, use it as is,
            // otherwise assume it is a relative path from the dataroot (for backwards compatibility reasons).
            if (strpos($attachpath, $temppath) !== 0) {
                $attachmentpath = $CFG->dataroot . '/' . $attachmentpath;
            }
            $mail->addAttachment($attachmentpath, $attachname, 'base64', $mimetype);
        }
    }
    // Check if the email should be sent in an other charset then the default UTF-8.
    if (!empty($CFG->sitemailcharset) || !empty($CFG->allowusermailcharset)) {
        // Use the defined site mail charset or eventually the one preferred by the recipient.
        $charset = $CFG->sitemailcharset;
        if (!empty($CFG->allowusermailcharset)) {
            if ($useremailcharset = get_user_preferences('mailcharset', '0', $user->id)) {
                $charset = $useremailcharset;
            }
        }
        // Convert all the necessary strings if the charset is supported.
        $charsets = get_list_of_charsets();
        unset($charsets['UTF-8']);
        if (in_array($charset, $charsets)) {
            $mail->CharSet = $charset;
            $mail->FromName = core_text::convert($mail->FromName, 'utf-8', strtolower($charset));
            $mail->Subject = core_text::convert($mail->Subject, 'utf-8', strtolower($charset));
            $mail->Body = core_text::convert($mail->Body, 'utf-8', strtolower($charset));
            $mail->AltBody = core_text::convert($mail->AltBody, 'utf-8', strtolower($charset));
            foreach ($temprecipients as $key => $values) {
                $temprecipients[$key][1] = core_text::convert($values[1], 'utf-8', strtolower($charset));
            }
            foreach ($tempreplyto as $key => $values) {
                $tempreplyto[$key][1] = core_text::convert($values[1], 'utf-8', strtolower($charset));
            }
        }
    }
    foreach ($temprecipients as $values) {
        $mail->addAddress($values[0], $values[1]);
    }
    foreach ($tempreplyto as $values) {
        $mail->addReplyTo($values[0], $values[1]);
    }
    if ($mail->send()) {
        set_send_count($user);
        if (!empty($mail->SMTPDebug)) {
            echo '</pre>';
        }
        return true;
    } else {
        // Trigger event for failing to send email.
        $event = \core\event\email_failed::create(array('context' => context_system::instance(), 'userid' => $from->id, 'relateduserid' => $user->id, 'other' => array('subject' => $subject, 'message' => $messagetext, 'errorinfo' => $mail->ErrorInfo)));
        $event->trigger();
        if (CLI_SCRIPT) {
            mtrace('Error: lib/moodlelib.php email_to_user(): ' . $mail->ErrorInfo);
        }
        if (!empty($mail->SMTPDebug)) {
            echo '</pre>';
        }
        return false;
    }
}

//.........这里部分代码省略.........
    }
    $mail->Subject = substr($subject, 0, 900);
    $temprecipients[] = array($user->email, fullname($user));
    // Set word wrap.
    $mail->WordWrap = $wordwrapwidth;
    if (!empty($from->customheaders)) {
        // Add custom headers.
        if (is_array($from->customheaders)) {
            foreach ($from->customheaders as $customheader) {
                $mail->addCustomHeader($customheader);
            }
        } else {
            $mail->addCustomHeader($from->customheaders);
        }
    }
    if (!empty($from->priority)) {
        $mail->Priority = $from->priority;
    }
    if ($messagehtml && !empty($user->mailformat) && $user->mailformat == 1) {
        // Don't ever send HTML to users who don't want it.
        $mail->isHTML(true);
        $mail->Encoding = 'quoted-printable';
        $mail->Body = $messagehtml;
        $mail->AltBody = "\n{$messagetext}\n";
    } else {
        $mail->IsHTML(false);
        $mail->Body = "\n{$messagetext}\n";
    }
    if ($attachment && $attachname) {
        if (preg_match("~\\.\\.~", $attachment)) {
            // Security check for ".." in dir path.
            $temprecipients[] = array($supportuser->email, fullname($supportuser, true));
            $mail->addStringAttachment('Error in attachment.  User attempted to attach a filename with a unsafe name.', 'error.txt', '8bit', 'text/plain');
        } else {
            require_once $CFG->libdir . '/filelib.php';
            $mimetype = mimeinfo('type', $attachname);
            $attachmentpath = $attachment;
            // Before doing the comparison, make sure that the paths are correct (Windows uses slashes in the other direction).
            $attachpath = str_replace('\\', '/', $attachmentpath);
            // Make sure both variables are normalised before comparing.
            $temppath = str_replace('\\', '/', $CFG->tempdir);
            // If the attachment is a full path to a file in the tempdir, use it as is,
            // otherwise assume it is a relative path from the dataroot (for backwards compatibility reasons).
            if (strpos($attachpath, realpath($temppath)) !== 0) {
                $attachmentpath = $CFG->dataroot . '/' . $attachmentpath;
            }
            $mail->addAttachment($attachmentpath, $attachname, 'base64', $mimetype);
        }
    }
    // Check if the email should be sent in an other charset then the default UTF-8.
    if (!empty($CFG->sitemailcharset) || !empty($CFG->allowusermailcharset)) {
        // Use the defined site mail charset or eventually the one preferred by the recipient.
        $charset = $CFG->sitemailcharset;
        if (!empty($CFG->allowusermailcharset)) {
            if ($useremailcharset = get_user_preferences('mailcharset', '0', $user->id)) {
                $charset = $useremailcharset;
            }
        }
        // Convert all the necessary strings if the charset is supported.
        $charsets = get_list_of_charsets();
        unset($charsets['UTF-8']);
        if (in_array($charset, $charsets)) {
            $mail->CharSet = $charset;
            $mail->FromName = core_text::convert($mail->FromName, 'utf-8', strtolower($charset));
            $mail->Subject = core_text::convert($mail->Subject, 'utf-8', strtolower($charset));
            $mail->Body = core_text::convert($mail->Body, 'utf-8', strtolower($charset));
            $mail->AltBody = core_text::convert($mail->AltBody, 'utf-8', strtolower($charset));
            foreach ($temprecipients as $key => $values) {
                $temprecipients[$key][1] = core_text::convert($values[1], 'utf-8', strtolower($charset));
            }
            foreach ($tempreplyto as $key => $values) {
                $tempreplyto[$key][1] = core_text::convert($values[1], 'utf-8', strtolower($charset));
            }
        }
    }
    foreach ($temprecipients as $values) {
        $mail->addAddress($values[0], $values[1]);
    }
    foreach ($tempreplyto as $values) {
        $mail->addReplyTo($values[0], $values[1]);
    }
    if ($mail->send()) {
        set_send_count($user);
        if (!empty($mail->SMTPDebug)) {
            echo '</pre>';
        }
        return true;
    } else {
        // Trigger event for failing to send email.
        $event = \core\event\email_failed::create(array('context' => context_system::instance(), 'userid' => $from->id, 'relateduserid' => $user->id, 'other' => array('subject' => $subject, 'message' => $messagetext, 'errorinfo' => $mail->ErrorInfo)));
        $event->trigger();
        if (CLI_SCRIPT) {
            mtrace('Error: lib/moodlelib.php email_to_user(): ' . $mail->ErrorInfo);
        }
        if (!empty($mail->SMTPDebug)) {
            echo '</pre>';
        }
        return false;
    }
}

//.........这里部分代码省略.........
            if (empty($replyto)) {
                $mail->AddReplyTo($CFG->noreplyaddress, get_string('noreplyname'));
            }
        }
    }
    if (!empty($replyto)) {
        $mail->AddReplyTo($replyto, $replytoname);
    }
    $mail->Subject = substr(stripslashes($subject), 0, 900);
    $mail->AddAddress(stripslashes($user->email), fullname($user));
    $mail->WordWrap = $wordwrapwidth;
    // set word wrap
    if (!empty($from->customheaders)) {
        // Add custom headers
        if (is_array($from->customheaders)) {
            foreach ($from->customheaders as $customheader) {
                $mail->AddCustomHeader($customheader);
            }
        } else {
            $mail->AddCustomHeader($from->customheaders);
        }
    }
    if (!empty($from->priority)) {
        $mail->Priority = $from->priority;
    }
    if ($messagehtml && $user->mailformat == 1) {
        // Don't ever send HTML to users who don't want it
        $mail->IsHTML(true);
        $mail->Encoding = 'quoted-printable';
        // Encoding to use
        $mail->Body = $messagehtml;
        $mail->AltBody = "\n{$messagetext}\n";
    } else {
        $mail->IsHTML(false);
        $mail->Body = "\n{$messagetext}\n";
    }
    if ($attachment && $attachname) {
        if (ereg("\\.\\.", $attachment)) {
            // Security check for ".." in dir path
            $mail->AddAddress($supportuser->email, fullname($supportuser, true));
            $mail->AddStringAttachment('Error in attachment.  User attempted to attach a filename with a unsafe name.', 'error.txt', '8bit', 'text/plain');
        } else {
            require_once $CFG->libdir . '/filelib.php';
            $mimetype = mimeinfo('type', $attachname);
            $mail->AddAttachment($CFG->dataroot . '/' . $attachment, $attachname, 'base64', $mimetype);
        }
    }
    /// If we are running under Unicode and sitemailcharset or allowusermailcharset are set, convert the email
    /// encoding to the specified one
    if (!empty($CFG->sitemailcharset) || !empty($CFG->allowusermailcharset)) {
        /// Set it to site mail charset
        $charset = $CFG->sitemailcharset;
        /// Overwrite it with the user mail charset
        if (!empty($CFG->allowusermailcharset)) {
            if ($useremailcharset = get_user_preferences('mailcharset', '0', $user->id)) {
                $charset = $useremailcharset;
            }
        }
        /// If it has changed, convert all the necessary strings
        $charsets = get_list_of_charsets();
        unset($charsets['UTF-8']);
        if (in_array($charset, $charsets)) {
            /// Save the new mail charset
            $mail->CharSet = $charset;
            /// And convert some strings
            $mail->FromName = $textlib->convert($mail->FromName, 'utf-8', $mail->CharSet);
            //From Name
            foreach ($mail->ReplyTo as $key => $rt) {
                //ReplyTo Names
                $mail->ReplyTo[$key][1] = $textlib->convert($rt[1], 'utf-8', $mail->CharSet);
            }
            $mail->Subject = $textlib->convert($mail->Subject, 'utf-8', $mail->CharSet);
            //Subject
            foreach ($mail->to as $key => $to) {
                $mail->to[$key][1] = $textlib->convert($to[1], 'utf-8', $mail->CharSet);
                //To Names
            }
            $mail->Body = $textlib->convert($mail->Body, 'utf-8', $mail->CharSet);
            //Body
            $mail->AltBody = $textlib->convert($mail->AltBody, 'utf-8', $mail->CharSet);
            //Subject
        }
    }
    if ($mail->Send()) {
        set_send_count($user);
        $mail->IsSMTP();
        // use SMTP directly
        if (!empty($mail->SMTPDebug)) {
            echo '</pre>';
        }
        return true;
    } else {
        mtrace('ERROR: ' . $mail->ErrorInfo);
        add_to_log(SITEID, 'library', 'mailer', $FULLME, 'ERROR: ' . $mail->ErrorInfo);
        if (!empty($mail->SMTPDebug)) {
            echo '</pre>';
        }
        return false;
    }
}

//.........这里部分代码省略.........
        } else {
            $mail->From = $CFG->noreplyaddress;
            $mail->FromName = fullname($from);
            if (empty($replyto)) {
                $tempreplyto[] = array($CFG->noreplyaddress, get_string('noreplyname'));
            }
        }
    }
    if (!empty($replyto)) {
        $tempreplyto[] = array($replyto, $replytoname);
    }
    $mail->Subject = substr($subject, 0, 900);
    $temprecipients[] = array($user->email, fullname($user));
    $mail->WordWrap = $wordwrapwidth;
    // set word wrap
    if (!empty($from->customheaders)) {
        // Add custom headers
        if (is_array($from->customheaders)) {
            foreach ($from->customheaders as $customheader) {
                $mail->AddCustomHeader($customheader);
            }
        } else {
            $mail->AddCustomHeader($from->customheaders);
        }
    }
    if (!empty($from->priority)) {
        $mail->Priority = $from->priority;
    }
    if ($messagehtml && !empty($user->mailformat) && $user->mailformat == 1) {
        // Don't ever send HTML to users who don't want it
        $mail->IsHTML(true);
        $mail->Encoding = 'quoted-printable';
        // Encoding to use
        $mail->Body = $messagehtml;
        $mail->AltBody = "\n{$messagetext}\n";
    } else {
        $mail->IsHTML(false);
        $mail->Body = "\n{$messagetext}\n";
    }
    if ($attachment && $attachname) {
        if (preg_match("~\\.\\.~", $attachment)) {
            // Security check for ".." in dir path
            $temprecipients[] = array($supportuser->email, fullname($supportuser, true));
            $mail->AddStringAttachment('Error in attachment.  User attempted to attach a filename with a unsafe name.', 'error.txt', '8bit', 'text/plain');
        } else {
            require_once $CFG->libdir . '/filelib.php';
            $mimetype = mimeinfo('type', $attachname);
            $mail->AddAttachment($CFG->dataroot . '/' . $attachment, $attachname, 'base64', $mimetype);
        }
    }
    // Check if the email should be sent in an other charset then the default UTF-8
    if (!empty($CFG->sitemailcharset) || !empty($CFG->allowusermailcharset)) {
        // use the defined site mail charset or eventually the one preferred by the recipient
        $charset = $CFG->sitemailcharset;
        if (!empty($CFG->allowusermailcharset)) {
            if ($useremailcharset = get_user_preferences('mailcharset', '0', $user->id)) {
                $charset = $useremailcharset;
            }
        }
        // convert all the necessary strings if the charset is supported
        $charsets = get_list_of_charsets();
        unset($charsets['UTF-8']);
        if (in_array($charset, $charsets)) {
            $textlib = textlib_get_instance();
            $mail->CharSet = $charset;
            $mail->FromName = $textlib->convert($mail->FromName, 'utf-8', strtolower($charset));
            $mail->Subject = $textlib->convert($mail->Subject, 'utf-8', strtolower($charset));
            $mail->Body = $textlib->convert($mail->Body, 'utf-8', strtolower($charset));
            $mail->AltBody = $textlib->convert($mail->AltBody, 'utf-8', strtolower($charset));
            foreach ($temprecipients as $key => $values) {
                $temprecipients[$key][1] = $textlib->convert($values[1], 'utf-8', strtolower($charset));
            }
            foreach ($tempreplyto as $key => $values) {
                $tempreplyto[$key][1] = $textlib->convert($values[1], 'utf-8', strtolower($charset));
            }
        }
    }
    foreach ($temprecipients as $values) {
        $mail->AddAddress($values[0], $values[1]);
    }
    foreach ($tempreplyto as $values) {
        $mail->AddReplyTo($values[0], $values[1]);
    }
    if ($mail->Send()) {
        set_send_count($user);
        $mail->IsSMTP();
        // use SMTP directly
        if (!empty($mail->SMTPDebug)) {
            echo '</pre>';
        }
        return true;
    } else {
        mtrace('ERROR: ' . $mail->ErrorInfo);
        add_to_log(SITEID, 'library', 'mailer', $FULLME, 'ERROR: ' . $mail->ErrorInfo);
        if (!empty($mail->SMTPDebug)) {
            echo '</pre>';
        }
        return false;
    }
}

//.........这里部分代码省略.........
            if (empty($replyto)) {
                $mail->AddReplyTo($CFG->noreplyaddress, get_string('noreplyname'));
            }
        }
    }
    if (!empty($replyto)) {
        $mail->AddReplyTo($replyto, $replytoname);
    }
    $mail->Subject = substr(stripslashes($subject), 0, 900);
    $mail->AddAddress($user->email, fullname($user));
    $mail->WordWrap = 79;
    // set word wrap
    if (!empty($from->customheaders)) {
        // Add custom headers
        if (is_array($from->customheaders)) {
            foreach ($from->customheaders as $customheader) {
                $mail->AddCustomHeader($customheader);
            }
        } else {
            $mail->AddCustomHeader($from->customheaders);
        }
    }
    if (!empty($from->priority)) {
        $mail->Priority = $from->priority;
    }
    if ($messagehtml && $user->mailformat == 1) {
        // Don't ever send HTML to users who don't want it
        $mail->IsHTML(true);
        $mail->Encoding = 'quoted-printable';
        // Encoding to use
        $mail->Body = $messagehtml;
        $mail->AltBody = "\n{$messagetext}\n";
    } else {
        $mail->IsHTML(false);
        $mail->Body = "\n{$messagetext}\n";
    }
    if ($attachment && $attachname) {
        if (ereg("\\.\\.", $attachment)) {
            // Security check for ".." in dir path
            $mail->AddAddress($supportuser->email, fullname($supportuser, true));
            $mail->AddStringAttachment('Error in attachment.  User attempted to attach a filename with a unsafe name.', 'error.txt', '8bit', 'text/plain');
        } else {
            require_once $CFG->libdir . '/filelib.php';
            $mimetype = mimeinfo('type', $attachname);
            $mail->AddAttachment($CFG->dataroot . '/' . $attachment, $attachname, 'base64', $mimetype);
        }
    }
    /// If we are running under Unicode and sitemailcharset or allowusermailcharset are set, convert the email
    /// encoding to the specified one
    if (!empty($CFG->sitemailcharset) || !empty($CFG->allowusermailcharset)) {
        /// Set it to site mail charset
        $charset = $CFG->sitemailcharset;
        /// Overwrite it with the user mail charset
        if (!empty($CFG->allowusermailcharset)) {
            if ($useremailcharset = get_user_preferences('mailcharset', '0', $user->id)) {
                $charset = $useremailcharset;
            }
        }
        /// If it has changed, convert all the necessary strings
        $charsets = get_list_of_charsets();
        unset($charsets['UTF-8']);
        if (in_array($charset, $charsets)) {
            /// Save the new mail charset
            $mail->CharSet = $charset;
            /// And convert some strings
            $mail->FromName = $textlib->convert($mail->FromName, 'utf-8', $mail->CharSet);
            //From Name
            foreach ($mail->ReplyTo as $key => $rt) {
                //ReplyTo Names
                $mail->ReplyTo[$key][1] = $textlib->convert($rt, 'utf-8', $mail->CharSet);
            }
            $mail->Subject = $textlib->convert($mail->Subject, 'utf-8', $mail->CharSet);
            //Subject
            foreach ($mail->to as $key => $to) {
                $mail->to[$key][1] = $textlib->convert($to, 'utf-8', $mail->CharSet);
                //To Names
            }
            $mail->Body = $textlib->convert($mail->Body, 'utf-8', $mail->CharSet);
            //Body
            $mail->AltBody = $textlib->convert($mail->AltBody, 'utf-8', $mail->CharSet);
            //Subject
        }
    }
    if ($mail->Send()) {
        set_send_count($user);
        $mail->IsSMTP();
        // use SMTP directly
        if (!empty($CFG->debugsmtp)) {
            echo '</pre>';
        }
        return true;
    } else {
        mtrace('ERROR: ' . $mail->ErrorInfo);
        add_to_log(SITEID, 'library', 'mailer', $FULLME, 'ERROR: ' . $mail->ErrorInfo);
        if (!empty($CFG->debugsmtp)) {
            echo '</pre>';
        }
        return false;
    }
}