/**
 * Send an email to a specified user
 *
 * @param stdClass $user  A {@link $USER} object
 * @param stdClass $from A {@link $USER} object
 * @param string $subject plain text subject line of the email
 * @param string $messagetext plain text version of the message
 * @param string $messagehtml complete html version of the message (optional)
 * @param string $attachment a file on the filesystem, either relative to $CFG->dataroot or a full path to a file in $CFG->tempdir
 * @param string $attachname the name of the file (extension indicates MIME)
 * @param bool $usetrueaddress determines whether $from email address should
 *          be sent out. Will be overruled by user profile setting for maildisplay
 * @param string $replyto Email address to reply to
 * @param string $replytoname Name of reply to recipient
 * @param int $wordwrapwidth custom word wrap width, default 79
 * @return bool Returns true if mail was sent OK and false if there was an error.
 */
function email_to_user($user, $from, $subject, $messagetext, $messagehtml = '', $attachment = '', $attachname = '', $usetrueaddress = true, $replyto = '', $replytoname = '', $wordwrapwidth = 79)
{
    global $CFG;
    if (empty($user) or empty($user->id)) {
        debugging('Can not send email to null user', DEBUG_DEVELOPER);
        return false;
    }
    if (empty($user->email)) {
        debugging('Can not send email to user without email: ' . $user->id, DEBUG_DEVELOPER);
        return false;
    }
    if (!empty($user->deleted)) {
        debugging('Can not send email to deleted user: ' . $user->id, DEBUG_DEVELOPER);
        return false;
    }
    if (defined('BEHAT_SITE_RUNNING')) {
        // Fake email sending in behat.
        return true;
    }
    if (!empty($CFG->noemailever)) {
        // Hidden setting for development sites, set in config.php if needed.
        debugging('Not sending email due to $CFG->noemailever config setting', DEBUG_NORMAL);
        return true;
    }
    if (!empty($CFG->divertallemailsto)) {
        $subject = "[DIVERTED {$user->email}] {$subject}";
        $user = clone $user;
        $user->email = $CFG->divertallemailsto;
    }
    // Skip mail to suspended users.
    if (isset($user->auth) && $user->auth == 'nologin' or isset($user->suspended) && $user->suspended) {
        return true;
    }
    if (!validate_email($user->email)) {
        // We can not send emails to invalid addresses - it might create security issue or confuse the mailer.
        debugging("email_to_user: User {$user->id} (" . fullname($user) . ") email ({$user->email}) is invalid! Not sending.");
        return false;
    }
    if (over_bounce_threshold($user)) {
        debugging("email_to_user: User {$user->id} (" . fullname($user) . ") is over bounce threshold! Not sending.");
        return false;
    }
    // TLD .invalid  is specifically reserved for invalid domain names.
    // For More information, see {@link http://tools.ietf.org/html/rfc2606#section-2}.
    if (substr($user->email, -8) == '.invalid') {
        debugging("email_to_user: User {$user->id} (" . fullname($user) . ") email domain ({$user->email}) is invalid! Not sending.");
        return true;
        // This is not an error.
    }
    // If the user is a remote mnet user, parse the email text for URL to the
    // wwwroot and modify the url to direct the user's browser to login at their
    // home site (identity provider - idp) before hitting the link itself.
    if (is_mnet_remote_user($user)) {
        require_once $CFG->dirroot . '/mnet/lib.php';
        $jumpurl = mnet_get_idp_jump_url($user);
        $callback = partial('mnet_sso_apply_indirection', $jumpurl);
        $messagetext = preg_replace_callback("%({$CFG->wwwroot}[^[:space:]]*)%", $callback, $messagetext);
        $messagehtml = preg_replace_callback("%href=[\"'`]({$CFG->wwwroot}[\\w_:\\?=#&@/;.~-]*)[\"'`]%", $callback, $messagehtml);
    }
    $mail = get_mailer();
    if (!empty($mail->SMTPDebug)) {
        echo '<pre>' . "\n";
    }
    $temprecipients = array();
    $tempreplyto = array();
    $supportuser = core_user::get_support_user();
    // Make up an email address for handling bounces.
    if (!empty($CFG->handlebounces)) {
        $modargs = 'B' . base64_encode(pack('V', $user->id)) . substr(md5($user->email), 0, 16);
        $mail->Sender = generate_email_processing_address(0, $modargs);
    } else {
        $mail->Sender = $supportuser->email;
    }
    if (!empty($CFG->emailonlyfromnoreplyaddress)) {
        $usetrueaddress = false;
        if (empty($replyto) && $from->maildisplay) {
            $replyto = $from->email;
            $replytoname = fullname($from);
        }
    }
    if (is_string($from)) {
        // So we can pass whatever we want if there is need.
        $mail->From = $CFG->noreplyaddress;
//.........这里部分代码省略.........

/**
 * Send an email to a specified user
 *
 * @param stdClass $user  A {@link $USER} object
 * @param stdClass $from A {@link $USER} object
 * @param string $subject plain text subject line of the email
 * @param string $messagetext plain text version of the message
 * @param string $messagehtml complete html version of the message (optional)
 * @param string $attachment a file on the filesystem, either relative to $CFG->dataroot or a full path to a file in $CFG->tempdir
 * @param string $attachname the name of the file (extension indicates MIME)
 * @param bool $usetrueaddress determines whether $from email address should
 *          be sent out. Will be overruled by user profile setting for maildisplay
 * @param string $replyto Email address to reply to
 * @param string $replytoname Name of reply to recipient
 * @param int $wordwrapwidth custom word wrap width, default 79
 * @return bool Returns true if mail was sent OK and false if there was an error.
 */
function email_to_user($user, $from, $subject, $messagetext, $messagehtml = '', $attachment = '', $attachname = '', $usetrueaddress = true, $replyto = '', $replytoname = '', $wordwrapwidth = 79)
{
    global $CFG, $PAGE, $SITE;
    if (empty($user) or empty($user->id)) {
        debugging('Can not send email to null user', DEBUG_DEVELOPER);
        return false;
    }
    if (empty($user->email)) {
        debugging('Can not send email to user without email: ' . $user->id, DEBUG_DEVELOPER);
        return false;
    }
    if (!empty($user->deleted)) {
        debugging('Can not send email to deleted user: ' . $user->id, DEBUG_DEVELOPER);
        return false;
    }
    if (defined('BEHAT_SITE_RUNNING')) {
        // Fake email sending in behat.
        return true;
    }
    if (!empty($CFG->noemailever)) {
        // Hidden setting for development sites, set in config.php if needed.
        debugging('Not sending email due to $CFG->noemailever config setting', DEBUG_NORMAL);
        return true;
    }
    if (email_should_be_diverted($user->email)) {
        $subject = "[DIVERTED {$user->email}] {$subject}";
        $user = clone $user;
        $user->email = $CFG->divertallemailsto;
    }
    // Skip mail to suspended users.
    if (isset($user->auth) && $user->auth == 'nologin' or isset($user->suspended) && $user->suspended) {
        return true;
    }
    if (!validate_email($user->email)) {
        // We can not send emails to invalid addresses - it might create security issue or confuse the mailer.
        debugging("email_to_user: User {$user->id} (" . fullname($user) . ") email ({$user->email}) is invalid! Not sending.");
        return false;
    }
    if (over_bounce_threshold($user)) {
        debugging("email_to_user: User {$user->id} (" . fullname($user) . ") is over bounce threshold! Not sending.");
        return false;
    }
    // TLD .invalid  is specifically reserved for invalid domain names.
    // For More information, see {@link http://tools.ietf.org/html/rfc2606#section-2}.
    if (substr($user->email, -8) == '.invalid') {
        debugging("email_to_user: User {$user->id} (" . fullname($user) . ") email domain ({$user->email}) is invalid! Not sending.");
        return true;
        // This is not an error.
    }
    // If the user is a remote mnet user, parse the email text for URL to the
    // wwwroot and modify the url to direct the user's browser to login at their
    // home site (identity provider - idp) before hitting the link itself.
    if (is_mnet_remote_user($user)) {
        require_once $CFG->dirroot . '/mnet/lib.php';
        $jumpurl = mnet_get_idp_jump_url($user);
        $callback = partial('mnet_sso_apply_indirection', $jumpurl);
        $messagetext = preg_replace_callback("%({$CFG->wwwroot}[^[:space:]]*)%", $callback, $messagetext);
        $messagehtml = preg_replace_callback("%href=[\"'`]({$CFG->wwwroot}[\\w_:\\?=#&@/;.~-]*)[\"'`]%", $callback, $messagehtml);
    }
    $mail = get_mailer();
    if (!empty($mail->SMTPDebug)) {
        echo '<pre>' . "\n";
    }
    $temprecipients = array();
    $tempreplyto = array();
    // Make sure that we fall back onto some reasonable no-reply address.
    $noreplyaddress = empty($CFG->noreplyaddress) ? 'noreply@' . get_host_from_url($CFG->wwwroot) : $CFG->noreplyaddress;
    // Make up an email address for handling bounces.
    if (!empty($CFG->handlebounces)) {
        $modargs = 'B' . base64_encode(pack('V', $user->id)) . substr(md5($user->email), 0, 16);
        $mail->Sender = generate_email_processing_address(0, $modargs);
    } else {
        $mail->Sender = $noreplyaddress;
    }
    $alloweddomains = null;
    if (!empty($CFG->allowedemaildomains)) {
        $alloweddomains = explode(PHP_EOL, $CFG->allowedemaildomains);
    }
    // Email will be sent using no reply address.
    if (empty($alloweddomains)) {
        $usetrueaddress = false;
    }
    if (is_string($from)) {
//.........这里部分代码省略.........

/**
 * Send an email to a specified user
 *
 * @global object
 * @global string
 * @global string IdentityProvider(IDP) URL user hits to jump to mnet peer.
 * @uses SITEID
 * @param stdClass $user  A {@link $USER} object
 * @param stdClass $from A {@link $USER} object
 * @param string $subject plain text subject line of the email
 * @param string $messagetext plain text version of the message
 * @param string $messagehtml complete html version of the message (optional)
 * @param string $attachment a file on the filesystem, relative to $CFG->dataroot
 * @param string $attachname the name of the file (extension indicates MIME)
 * @param bool $usetrueaddress determines whether $from email address should
 *          be sent out. Will be overruled by user profile setting for maildisplay
 * @param string $replyto Email address to reply to
 * @param string $replytoname Name of reply to recipient
 * @param int $wordwrapwidth custom word wrap width, default 79
 * @return bool Returns true if mail was sent OK and false if there was an error.
 */
function email_to_user($user, $from, $subject, $messagetext, $messagehtml = '', $attachment = '', $attachname = '', $usetrueaddress = true, $replyto = '', $replytoname = '', $wordwrapwidth = 79)
{
    global $CFG, $FULLME;
    if (empty($user) || empty($user->email)) {
        mtrace('Error: lib/moodlelib.php email_to_user(): User is null or has no email');
        return false;
    }
    if (!empty($user->deleted)) {
        // do not mail delted users
        mtrace('Error: lib/moodlelib.php email_to_user(): User is deleted');
        return false;
    }
    if (!empty($CFG->noemailever)) {
        // hidden setting for development sites, set in config.php if needed
        mtrace('Error: lib/moodlelib.php email_to_user(): Not sending email due to noemailever config setting');
        return true;
    }
    if (!empty($CFG->divertallemailsto)) {
        $subject = "[DIVERTED {$user->email}] {$subject}";
        $user = clone $user;
        $user->email = $CFG->divertallemailsto;
    }
    // skip mail to suspended users
    if (isset($user->auth) && $user->auth == 'nologin') {
        return true;
    }
    if (over_bounce_threshold($user)) {
        $bouncemsg = "User {$user->id} (" . fullname($user) . ") is over bounce threshold! Not sending.";
        error_log($bouncemsg);
        mtrace('Error: lib/moodlelib.php email_to_user(): ' . $bouncemsg);
        return false;
    }
    // If the user is a remote mnet user, parse the email text for URL to the
    // wwwroot and modify the url to direct the user's browser to login at their
    // home site (identity provider - idp) before hitting the link itself
    if (is_mnet_remote_user($user)) {
        require_once $CFG->dirroot . '/mnet/lib.php';
        $jumpurl = mnet_get_idp_jump_url($user);
        $callback = partial('mnet_sso_apply_indirection', $jumpurl);
        $messagetext = preg_replace_callback("%({$CFG->wwwroot}[^[:space:]]*)%", $callback, $messagetext);
        $messagehtml = preg_replace_callback("%href=[\"'`]({$CFG->wwwroot}[\\w_:\\?=#&@/;.~-]*)[\"'`]%", $callback, $messagehtml);
    }
    $mail = get_mailer();
    if (!empty($mail->SMTPDebug)) {
        echo '<pre>' . "\n";
    }
    $temprecipients = array();
    $tempreplyto = array();
    $supportuser = generate_email_supportuser();
    // make up an email address for handling bounces
    if (!empty($CFG->handlebounces)) {
        $modargs = 'B' . base64_encode(pack('V', $user->id)) . substr(md5($user->email), 0, 16);
        $mail->Sender = generate_email_processing_address(0, $modargs);
    } else {
        $mail->Sender = $supportuser->email;
    }
    if (is_string($from)) {
        // So we can pass whatever we want if there is need
        $mail->From = $CFG->noreplyaddress;
        $mail->FromName = $from;
    } else {
        if ($usetrueaddress and $from->maildisplay) {
            $mail->From = $from->email;
            $mail->FromName = fullname($from);
        } 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
//.........这里部分代码省略.........