mail.inc

<?php


/**
 * @file
 * API functions for processing and sending e-mail.
 */

/**
 * Auto-detect appropriate line endings for e-mails.
 *
 * $conf['mail_line_endings'] will override this setting.
 */
define('MAIL_LINE_ENDINGS', isset($_SERVER['WINDIR']) || isset($_SERVER['SERVER_SOFTWARE']) && strpos($_SERVER['SERVER_SOFTWARE'], 'Win32') !== FALSE ? "\r\n" : "\n");

/**
 * Special characters, defined in RFC_2822.
 */
define('MAIL_RFC_2822_SPECIALS', '()<>[]:;@\\,."');

/**
 * Composes and optionally sends an e-mail message.
 *
 * Sending an e-mail works with defining an e-mail template (subject, text
 * and possibly e-mail headers) and the replacement values to use in the
 * appropriate places in the template. Processed e-mail templates are
 * requested from hook_mail() from the module sending the e-mail. Any module
 * can modify the composed e-mail message array using hook_mail_alter().
 * Finally drupal_mail_system()->mail() sends the e-mail, which can
 * be reused if the exact same composed e-mail is to be sent to multiple
 * recipients.
 *
 * Finding out what language to send the e-mail with needs some consideration.
 * If you send e-mail to a user, her preferred language should be fine, so
 * use user_preferred_language(). If you send email based on form values
 * filled on the page, there are two additional choices if you are not
 * sending the e-mail to a user on the site. You can either use the language
 * used to generate the page ($language global variable) or the site default
 * language. See language_default(). The former is good if sending e-mail to
 * the person filling the form, the later is good if you send e-mail to an
 * address previously set up (like contact addresses in a contact form).
 *
 * Taking care of always using the proper language is even more important
 * when sending e-mails in a row to multiple users. Hook_mail() abstracts
 * whether the mail text comes from an administrator setting or is
 * static in the source code. It should also deal with common mail tokens,
 * only receiving $params which are unique to the actual e-mail at hand.
 *
 * An example:
 *
 * @code
 *   function example_notify($accounts) {
 *     foreach ($accounts as $account) {
 *       $params['account'] = $account;
 *       // example_mail() will be called based on the first drupal_mail() parameter.
 *       drupal_mail('example', 'notice', $account->mail, user_preferred_language($account), $params);
 *     }
 *   }
 *
 *   function example_mail($key, &$message, $params) {
 *     $data['user'] = $params['account'];
 *     $options['language'] = $message['language'];
 *     user_mail_tokens($variables, $data, $options);
 *     switch($key) {
 *       case 'notice':
 *         // If the recipient can receive such notices by instant-message, do
 *         // not send by email.
 *         if (example_im_send($key, $message, $params)) {
 *           $message['send'] = FALSE;
 *           break;
 *         }
 *         $langcode = $message['language']->language;
 *         $message['subject'] = t('Notification from !site', $variables, array('langcode' => $langcode));
 *         $message['body'][] = t("Dear !username\n\nThere is new content available on the site.", $variables, array('langcode' => $langcode));
 *         break;
 *     }
 *   }
 * @endcode
 *
 * Another example, which uses drupal_mail() to format a message for sending
 * later:
 *
 * @code
 *   $params = array('current_conditions' => $data);
 *   $to = 'user@example.com';
 *   $message = drupal_mail('example', 'notice', $to, $language, $params, FALSE);
 *   // Only add to the spool if sending was not canceled.
 *   if ($message['send']) {
 *     example_spool_message($message);
 *   }
 * @endcode
 *
 * @param $module
 *   A module name to invoke hook_mail() on. The {$module}_mail() hook will be
 *   called to complete the $message structure which will already contain common
 *   defaults.
 * @param $key
 *   A key to identify the e-mail sent. The final e-mail id for e-mail altering
 *   will be {$module}_{$key}.
 * @param $to
 *   The e-mail address or addresses where the message will be sent to. The
 *   formatting of this string will be validated with the
 *   @link http://php.net/manual/filter.filters.validate.php PHP e-mail validation filter. @endlink
 *   Some examples are:
 *   - user@example.com
 *   - user@example.com, anotheruser@example.com
 *   - User <user@example.com>
 *   - User <user@example.com>, Another User <anotheruser@example.com>
 * @param $language
 *   Language object to use to compose the e-mail.
 * @param $params
 *   Optional parameters to build the e-mail.
 * @param $from
 *   Sets From to this value, if given.
 * @param $send
 *   If TRUE, drupal_mail() will call drupal_mail_system()->mail() to deliver
 *   the message, and store the result in $message['result']. Modules
 *   implementing hook_mail_alter() may cancel sending by setting
 *   $message['send'] to FALSE.
 *
 * @return
 *   The $message array structure containing all details of the
 *   message. If already sent ($send = TRUE), then the 'result' element
 *   will contain the success indicator of the e-mail, failure being already
 *   written to the watchdog. (Success means nothing more than the message being
 *   accepted at php-level, which still doesn't guarantee it to be delivered.)
 */
function drupal_mail($module, $key, $to, $language, $params = array(), $from = NULL, $send = TRUE) {
    $default_from = variable_get('site_mail', ini_get('sendmail_from'));
    // Bundle up the variables into a structured array for altering.
    $message = array(
        'id' => $module . '_' . $key,
        'module' => $module,
        'key' => $key,
        'to' => $to,
        'from' => isset($from) ? $from : $default_from,
        'language' => $language,
        'params' => $params,
        'send' => TRUE,
        'subject' => '',
        'body' => array(),
    );
    // Build the default headers
    $headers = array(
        'MIME-Version' => '1.0',
        'Content-Type' => 'text/plain; charset=UTF-8; format=flowed; delsp=yes',
        'Content-Transfer-Encoding' => '8Bit',
        'X-Mailer' => 'Drupal',
    );
    if ($default_from) {
        // To prevent e-mail from looking like spam, the addresses in the Sender and
        // Return-Path headers should have a domain authorized to use the originating
        // SMTP server.
        $headers['From'] = $headers['Sender'] = $headers['Return-Path'] = $default_from;
        if (variable_get('mail_display_name_site_name', FALSE)) {
            $display_name = variable_get('site_name', 'Drupal');
            $headers['From'] = drupal_mail_format_display_name($display_name) . ' <' . $default_from . '>';
        }
    }
    if ($from && $from != $default_from) {
        $headers['From'] = $from;
    }
    $message['headers'] = $headers;
    // Build the e-mail (get subject and body, allow additional headers) by
    // invoking hook_mail() on this module. We cannot use module_invoke() as
    // we need to have $message by reference in hook_mail().
    if (function_exists($function = $module . '_mail')) {
        $function($key, $message, $params);
    }
    // Invoke hook_mail_alter() to allow all modules to alter the resulting e-mail.
    drupal_alter('mail', $message);
    // Retrieve the responsible implementation for this message.
    $system = drupal_mail_system($module, $key);
    // Format the message body.
    $message = $system->format($message);
    // Optionally send e-mail.
    if ($send) {
        // The original caller requested sending. Sending was canceled by one or
        // more hook_mail_alter() implementations. We set 'result' to NULL, because
        // FALSE indicates an error in sending.
        if (empty($message['send'])) {
            $message['result'] = NULL;
        }
        else {
            $message['result'] = $system->mail($message);
            // Log errors.
            if (!$message['result']) {
                watchdog('mail', 'Error sending e-mail (from %from to %to).', array(
                    '%from' => $message['from'],
                    '%to' => $message['to'],
                ), WATCHDOG_ERROR);
                drupal_set_message(t('Unable to send e-mail. Contact the site administrator if the problem persists.'), 'error');
            }
        }
    }
    return $message;
}

/**
 * Returns an object that implements the MailSystemInterface interface.
 *
 * Allows for one or more custom mail backends to format and send mail messages
 * composed using drupal_mail().
 *
 * An implementation needs to implement the following methods:
 * - format: Allows to preprocess, format, and postprocess a mail
 *   message before it is passed to the sending system. By default, all messages
 *   may contain HTML and are converted to plain-text by the DefaultMailSystem
 *   implementation. For example, an alternative implementation could override
 *   the default implementation and additionally sanitize the HTML for usage in
 *   a MIME-encoded e-mail, but still invoking the DefaultMailSystem
 *   implementation to generate an alternate plain-text version for sending.
 * - mail: Sends a message through a custom mail sending engine.
 *   By default, all messages are sent via PHP's mail() function by the
 *   DefaultMailSystem implementation.
 *
 * The selection of a particular implementation is controlled via the variable
 * 'mail_system', which is a keyed array.  The default implementation
 * is the class whose name is the value of 'default-system' key. A more specific
 * match first to key and then to module will be used in preference to the
 * default. To specify a different class for all mail sent by one module, set
 * the class name as the value for the key corresponding to the module name. To
 * specify a class for a particular message sent by one module, set the class
 * name as the value for the array key that is the message id, which is
 * "${module}_${key}".
 *
 * For example to debug all mail sent by the user module by logging it to a
 * file, you might set the variable as something like:
 *
 * @code
 * array(
 *   'default-system' => 'DefaultMailSystem',
 *   'user' => 'DevelMailLog',
 * );
 * @endcode
 *
 * Finally, a different system can be specified for a specific e-mail ID (see
 * the $key param), such as one of the keys used by the contact module:
 *
 * @code
 * array(
 *   'default-system' => 'DefaultMailSystem',
 *   'user' => 'DevelMailLog',
 *   'contact_page_autoreply' => 'DrupalDevNullMailSend',
 * );
 * @endcode
 *
 * Other possible uses for system include a mail-sending class that actually
 * sends (or duplicates) each message to SMS, Twitter, instant message, etc, or
 * a class that queues up a large number of messages for more efficient bulk
 * sending or for sending via a remote gateway so as to reduce the load
 * on the local server.
 *
 * @param $module
 *   The module name which was used by drupal_mail() to invoke hook_mail().
 * @param $key
 *   A key to identify the e-mail sent. The final e-mail ID for the e-mail
 *   alter hook in drupal_mail() would have been {$module}_{$key}.
 *
 * @return MailSystemInterface
 */
function drupal_mail_system($module, $key) {
    $instances =& drupal_static(__FUNCTION__, array());
    $id = $module . '_' . $key;
    $configuration = variable_get('mail_system', array(
        'default-system' => 'DefaultMailSystem',
    ));
    // Look for overrides for the default class, starting from the most specific
    // id, and falling back to the module name.
    if (isset($configuration[$id])) {
        $class = $configuration[$id];
    }
    elseif (isset($configuration[$module])) {
        $class = $configuration[$module];
    }
    else {
        $class = $configuration['default-system'];
    }
    if (empty($instances[$class])) {
        $interfaces = class_implements($class);
        if (isset($interfaces['MailSystemInterface'])) {
            $instances[$class] = new $class();
        }
        else {
            throw new Exception(t('Class %class does not implement interface %interface', array(
                '%class' => $class,
                '%interface' => 'MailSystemInterface',
            )));
        }
    }
    return $instances[$class];
}

/**
 * An interface for pluggable mail back-ends.
 */
interface MailSystemInterface {
    
    /**
     * Format a message composed by drupal_mail() prior sending.
     *
     * @param $message
     *   A message array, as described in hook_mail_alter().
     *
     * @return
     *   The formatted $message.
     */
    public function format(array $message);
    
    /**
     * Send a message composed by drupal_mail().
     *
     * @param $message
     *   Message array with at least the following elements:
     *   - id: A unique identifier of the e-mail type. Examples: 'contact_user_copy',
     *     'user_password_reset'.
     *   - to: The mail address or addresses where the message will be sent to.
     *     The formatting of this string will be validated with the
     *     @link http://php.net/manual/filter.filters.validate.php PHP e-mail validation filter. @endlink
     *     Some examples are:
     *     - user@example.com
     *     - user@example.com, anotheruser@example.com
     *     - User <user@example.com>
     *     - User <user@example.com>, Another User <anotheruser@example.com>
     *   - subject: Subject of the e-mail to be sent. This must not contain any
     *     newline characters, or the mail may not be sent properly.
     *   - body: Message to be sent. Accepts both CRLF and LF line-endings.
     *     E-mail bodies must be wrapped. You can use drupal_wrap_mail() for
     *     smart plain text wrapping.
     *   - headers: Associative array containing all additional mail headers not
     *     defined by one of the other parameters.  PHP's mail() looks for Cc and
     *     Bcc headers and sends the mail to addresses in these headers too.
     *
     * @return
     *   TRUE if the mail was successfully accepted for delivery, otherwise FALSE.
     */
    public function mail(array $message);

}

/**
 * Performs format=flowed soft wrapping for mail (RFC 3676).
 *
 * We use delsp=yes wrapping, but only break non-spaced languages when
 * absolutely necessary to avoid compatibility issues.
 *
 * We deliberately use LF rather than CRLF, see drupal_mail().
 *
 * @param string $text
 *   The plain text to process.
 * @param string $indent (optional)
 *   A string to indent the text with. Only '>' characters are repeated on
 *   subsequent wrapped lines. Others are replaced by spaces.
 *
 * @return string
 *   The content of the email as a string with formatting applied.
 */
function drupal_wrap_mail($text, $indent = '') {
    // Convert CRLF into LF.
    $text = str_replace("\r", '', $text);
    // See if soft-wrapping is allowed.
    $clean_indent = _drupal_html_to_text_clean($indent);
    $soft = strpos($clean_indent, ' ') === FALSE;
    // Check if the string has line breaks.
    if (strpos($text, "\n") !== FALSE) {
        // Remove trailing spaces to make existing breaks hard, but leave signature
        // marker untouched (RFC 3676, Section 4.3).
        $text = preg_replace('/(?(?<!^--) +\\n|  +\\n)/m', "\n", $text);
        // Wrap each line at the needed width.
        $lines = explode("\n", $text);
        array_walk($lines, '_drupal_wrap_mail_line', array(
            'soft' => $soft,
            'length' => strlen($indent),
        ));
        $text = implode("\n", $lines);
    }
    else {
        // Wrap this line.
        _drupal_wrap_mail_line($text, 0, array(
            'soft' => $soft,
            'length' => strlen($indent),
        ));
    }
    // Empty lines with nothing but spaces.
    $text = preg_replace('/^ +\\n/m', "\n", $text);
    // Space-stuff special lines.
    $text = preg_replace('/^(>| |From)/m', ' $1', $text);
    // Apply indentation. We only include non-'>' indentation on the first line.
    $text = $indent . substr(preg_replace('/^/m', $clean_indent, $text), strlen($indent));
    return $text;
}

/**
 * Transforms an HTML string into plain text, preserving its structure.
 *
 * The output will be suitable for use as 'format=flowed; delsp=yes' text
 * (RFC 3676) and can be passed directly to drupal_mail() for sending.
 *
 * We deliberately use LF rather than CRLF, see drupal_mail().
 *
 * This function provides suitable alternatives for the following tags:
 * <a> <em> <i> <strong> <b> <br> <p> <blockquote> <ul> <ol> <li> <dl> <dt>
 * <dd> <h1> <h2> <h3> <h4> <h5> <h6> <hr>
 *
 * @param $string
 *   The string to be transformed.
 * @param $allowed_tags (optional)
 *   If supplied, a list of tags that will be transformed. If omitted, all
 *   all supported tags are transformed.
 *
 * @return
 *   The transformed string.
 */
function drupal_html_to_text($string, $allowed_tags = NULL) {
    // Cache list of supported tags.
    static $supported_tags;
    if (empty($supported_tags)) {
        $supported_tags = array(
            'a',
            'em',
            'i',
            'strong',
            'b',
            'br',
            'p',
            'blockquote',
            'ul',
            'ol',
            'li',
            'dl',
            'dt',
            'dd',
            'h1',
            'h2',
            'h3',
            'h4',
            'h5',
            'h6',
            'hr',
        );
    }
    // Make sure only supported tags are kept.
    $allowed_tags = isset($allowed_tags) ? array_intersect($supported_tags, $allowed_tags) : $supported_tags;
    // Make sure tags, entities and attributes are well-formed and properly nested.
    $string = _filter_htmlcorrector(filter_xss($string, $allowed_tags));
    // Apply inline styles.
    $string = preg_replace('!</?(em|i)((?> +)[^>]*)?>!i', '/', $string);
    $string = preg_replace('!</?(strong|b)((?> +)[^>]*)?>!i', '*', $string);
    // Replace inline <a> tags with the text of link and a footnote.
    // 'See <a href="http://drupal.org">the Drupal site</a>' becomes
    // 'See the Drupal site [1]' with the URL included as a footnote.
    _drupal_html_to_mail_urls(NULL, TRUE);
    $pattern = '@(<a[^>]+?href="([^"]*)"[^>]*?>(.+?)</a>)@i';
    $string = preg_replace_callback($pattern, '_drupal_html_to_mail_urls', $string);
    $urls = _drupal_html_to_mail_urls();
    $footnotes = '';
    if (count($urls)) {
        $footnotes .= "\n";
        for ($i = 0, $max = count($urls); $i < $max; $i++) {
            $footnotes .= '[' . ($i + 1) . '] ' . $urls[$i] . "\n";
        }
    }
    // Split tags from text.
    $split = preg_split('/<([^>]+?)>/', $string, -1, PREG_SPLIT_DELIM_CAPTURE);
    // Note: PHP ensures the array consists of alternating delimiters and literals
    // and begins and ends with a literal (inserting $null as required).
    $tag = FALSE;
    // Odd/even counter (tag or no tag)
    $casing = NULL;
    // Case conversion function
    $output = '';
    $indent = array();
    // All current indentation string chunks
    $lists = array();
    // Array of counters for opened lists
    foreach ($split as $value) {
        $chunk = NULL;
        // Holds a string ready to be formatted and output.
        // Process HTML tags (but don't output any literally).
        if ($tag) {
            list($tagname) = explode(' ', strtolower($value), 2);
            switch ($tagname) {
                // List counters
                case 'ul':
                    array_unshift($lists, '*');
                    break;
                case 'ol':
                    array_unshift($lists, 1);
                    break;
                case '/ul':
                case '/ol':
                    array_shift($lists);
                    $chunk = '';
                    // Ensure blank new-line.
                    break;
                // Quotation/list markers, non-fancy headers
                case 'blockquote':
                    // Format=flowed indentation cannot be mixed with lists.
                    $indent[] = count($lists) ? ' "' : '>';
                    break;
                case 'li':
                    $indent[] = isset($lists[0]) && is_numeric($lists[0]) ? ' ' . $lists[0]++ . ') ' : ' * ';
                    break;
                case 'dd':
                    $indent[] = '    ';
                    break;
                case 'h3':
                    $indent[] = '.... ';
                    break;
                case 'h4':
                    $indent[] = '.. ';
                    break;
                case '/blockquote':
                    if (count($lists)) {
                        // Append closing quote for inline quotes (immediately).
                        $output = rtrim($output, "> \n") . "\"\n";
                        $chunk = '';
                        // Ensure blank new-line.
                    }
                // Fall-through
                case '/li':
                case '/dd':
                    array_pop($indent);
                    break;
                case '/h3':
                case '/h4':
                    array_pop($indent);
                case '/h5':
                case '/h6':
                    $chunk = '';
                    // Ensure blank new-line.
                    break;
                // Fancy headers
                case 'h1':
                    $indent[] = '======== ';
                    $casing = 'drupal_strtoupper';
                    break;
                case 'h2':
                    $indent[] = '-------- ';
                    $casing = 'drupal_strtoupper';
                    break;
                case '/h1':
                case '/h2':
                    $casing = NULL;
                    // Pad the line with dashes.
                    $output = _drupal_html_to_text_pad($output, $tagname == '/h1' ? '=' : '-', ' ');
                    array_pop($indent);
                    $chunk = '';
                    // Ensure blank new-line.
                    break;
                // Horizontal rulers
                case 'hr':
                    // Insert immediately.
                    $output .= drupal_wrap_mail('', implode('', $indent)) . "\n";
                    $output = _drupal_html_to_text_pad($output, '-');
                    break;
                // Paragraphs and definition lists
                case '/p':
                case '/dl':
                    $chunk = '';
                    // Ensure blank new-line.
                    break;
            }
        }
        else {
            // Convert inline HTML text to plain text; not removing line-breaks or
            // white-space, since that breaks newlines when sanitizing plain-text.
            $value = trim(decode_entities($value));
            if (drupal_strlen($value)) {
                $chunk = $value;
            }
        }
        // See if there is something waiting to be output.
        if (isset($chunk)) {
            // Apply any necessary case conversion.
            if (isset($casing)) {
                $chunk = $casing($chunk);
            }
            // Format it and apply the current indentation.
            $output .= drupal_wrap_mail($chunk, implode('', $indent)) . MAIL_LINE_ENDINGS;
            // Remove non-quotation markers from indentation.
            $indent = array_map('_drupal_html_to_text_clean', $indent);
        }
        $tag = !$tag;
    }
    return $output . $footnotes;
}

/**
 * Return a RFC-2822 compliant "display-name" component.
 *
 * The "display-name" component is used in mail header "Originator" fields
 * (From, Sender, Reply-to) to give a human-friendly description of the
 * address, i.e. From: My Display Name <xyz@example.org>. RFC-822 and
 * RFC-2822 define its syntax and rules. This method gets as input a string
 * to be used as "display-name" and formats it to be RFC compliant.
 *
 * @param string $string
 *   A string to be used as "display-name".
 *
 * @return string
 *   A RFC compliant version of the string, ready to be used as
 *   "display-name" in mail originator header fields.
 */
function drupal_mail_format_display_name($string) {
    // Make sure we don't process html-encoded characters. They may create
    // unneeded trouble if left encoded, besides they will be correctly
    // processed if decoded.
    $string = decode_entities($string);
    // If string contains non-ASCII characters it must be (short) encoded
    // according to RFC-2047. The output of a "B" (Base64) encoded-word is
    // always safe to be used as display-name.
    $safe_display_name = mime_header_encode($string, TRUE);
    // Encoded-words are always safe to be used as display-name because don't
    // contain any RFC 2822 "specials" characters. However
    // mimeHeaderEncode() encodes a string only if it contains any
    // non-ASCII characters, and leaves its value untouched (un-encoded) if
    // ASCII only. For this reason in order to produce a valid display-name we
    // still need to make sure there are no "specials" characters left.
    if (preg_match('/[' . preg_quote(MAIL_RFC_2822_SPECIALS) . ']/', $safe_display_name)) {
        // If string is already quoted, it may or may not be escaped properly, so
        // don't trust it and reset.
        if (preg_match('/^"(.+)"$/', $safe_display_name, $matches)) {
            $safe_display_name = str_replace(array(
                '\\\\',
                '\\"',
            ), array(
                '\\',
                '"',
            ), $matches[1]);
        }
        // Transform the string in a RFC-2822 "quoted-string" by wrapping it in
        // double-quotes. Also make sure '"' and '\' occurrences are escaped.
        $safe_display_name = '"' . str_replace(array(
            '\\',
            '"',
        ), array(
            '\\\\',
            '\\"',
        ), $safe_display_name) . '"';
    }
    return $safe_display_name;
}

/**
 * Wraps words on a single line.
 *
 * Callback for array_walk() within drupal_wrap_mail().
 */
function _drupal_wrap_mail_line(&$line, $key, $values) {
    // Use soft-breaks only for purely quoted or unindented text.
    $line = wordwrap($line, 77 - $values['length'], $values['soft'] ? " \n" : "\n");
    // Break really long words at the maximum width allowed.
    $line = wordwrap($line, 996 - $values['length'], $values['soft'] ? " \n" : "\n", TRUE);
}

/**
 * Keeps track of URLs and replaces them with placeholder tokens.
 *
 * Callback for preg_replace_callback() within drupal_html_to_text().
 */
function _drupal_html_to_mail_urls($match = NULL, $reset = FALSE) {
    global $base_url, $base_path;
    static $urls = array(), $regexp;
    if ($reset) {
        // Reset internal URL list.
        $urls = array();
    }
    else {
        if (empty($regexp)) {
            $regexp = '@^' . preg_quote($base_path, '@') . '@';
        }
        if ($match) {
            list(, , $url, $label) = $match;
            // Ensure all URLs are absolute.
            $urls[] = strpos($url, '://') ? $url : preg_replace($regexp, $base_url . '/', $url);
            return $label . ' [' . count($urls) . ']';
        }
    }
    return $urls;
}

/**
 * Replaces non-quotation markers from a given piece of indentation with spaces.
 *
 * Callback for array_map() within drupal_html_to_text().
 */
function _drupal_html_to_text_clean($indent) {
    return preg_replace('/[^>]/', ' ', $indent);
}

/**
 * Pads the last line with the given character.
 *
 * @see drupal_html_to_text()
 */
function _drupal_html_to_text_pad($text, $pad, $prefix = '') {
    // Remove last line break.
    $text = substr($text, 0, -1);
    // Calculate needed padding space and add it.
    if (($p = strrpos($text, "\n")) === FALSE) {
        $p = -1;
    }
    $n = max(0, 79 - (strlen($text) - $p) - strlen($prefix));
    // Add prefix and padding, and restore linebreak.
    return $text . $prefix . str_repeat($pad, $n) . "\n";
}