<?php
// $Id: print_pdf.module,v 1.65 2010-08-21 23:12:56 jcnventura Exp $

/**
 * @file
 * Displays Printer-friendly versions of Drupal pages.
 *
 * @ingroup print
 */

define('PRINTPDF_PATH', 'printpdf');

define('PRINT_PDF_FORMAT', 'pdf');

define('PRINT_PDF_LIB_PATH', 'sites/all/libraries');

define('PRINT_PDF_LINK_POS_DEFAULT', 'link');
define('PRINT_PDF_LINK_TEASER_DEFAULT', 0);
define('PRINT_PDF_SHOW_LINK_DEFAULT', 1);
define('PRINT_PDF_NODE_LINK_VISIBILITY_DEFAULT', 0);
define('PRINT_PDF_NODE_LINK_PAGES_DEFAULT', '');
define('PRINT_PDF_LINK_CLASS_DEFAULT', 'print-pdf');
define('PRINT_PDF_SYS_LINK_VISIBILITY_DEFAULT', 1);
define('PRINT_PDF_SYS_LINK_PAGES_DEFAULT', '');
define('PRINT_PDF_LINK_USE_ALIAS_DEFAULT', 0);
define('PRINT_PDF_BOOK_LINK_DEFAULT', 1);
define('PRINT_PDF_PDF_TOOL_DEFAULT', 0);
define('PRINT_PDF_CONTENT_DISPOSITION_DEFAULT', 2);
define('PRINT_PDF_PAPER_SIZE_DEFAULT', 'A4');
define('PRINT_PDF_PAGE_ORIENTATION_DEFAULT', 'portrait');
define('PRINT_PDF_AUTOCONFIG_DEFAULT', 1);
define('PRINT_PDF_FONT_FAMILY_DEFAULT', 'dejavusans');
define('PRINT_PDF_FONT_SIZE_DEFAULT', 10);
define('PRINT_PDF_FILENAME_DEFAULT', '[site:name] - [node:title] - [node:changed:custom:Y-m-d]');
define('PRINT_PDF_DOMPDF_UNICODE_DEFAULT', 0);
define('PRINT_PDF_WKHTMLTOPDF_OPTIONS', "--footer-font-size 7 --footer-right '[page]'");

/**
 * Implements hook_permission().
 */
function print_pdf_permission() {
  return array(
    'access PDF version' => array(
      'title' => t('Access the PDF version'),
      'description' => t('View the PDF versions and the links to them in the original pages.'),
    ),
  );
}

/**
 * Implements hook_theme().
 */
function print_pdf_theme() {
  return array(
    'print_pdf_format_link' => array(
      'variables' => array(),
    ),
    'print_pdf_dompdf_footer' => array(
      'variables' => array('html' => ''),
      'file' => 'print_pdf.pages.inc',
    ),
    'print_pdf_tcpdf_header' => array(
      'variables' => array('pdf' => NULL, 'html' => '', 'font' => array()),
      'file' => 'print_pdf.pages.inc',
    ),
    'print_pdf_tcpdf_page' => array(
      'variables' => array('pdf' => NULL),
      'file' => 'print_pdf.pages.inc',
    ),
    'print_pdf_tcpdf_content' => array(
      'variables' => array('pdf' => NULL, 'html' => '', 'font' => array()),
      'file' => 'print_pdf.pages.inc',
    ),
    'print_pdf_tcpdf_footer' => array(
      'variables' => array('pdf' => NULL, 'html' => '', 'font' => array()),
      'file' => 'print_pdf.pages.inc',
    ),
    'print_pdf_tcpdf_footer2' => array(
      'variables' => array('pdf' => NULL),
      'file' => 'print_pdf.pages.inc',
    ),
  );
}

/**
 * Implements hook_menu().
 */
function print_pdf_menu() {
  $items = array();

  $items[PRINTPDF_PATH] = array(
    'title' => 'Printer-friendly PDF',
    'page callback' => 'print_pdf_controller',
    'access arguments' => array('access PDF version'),
    'type' => MENU_CALLBACK,
    'file' => 'print_pdf.pages.inc',
  );
  $items[PRINTPDF_PATH . '/' . PRINTPDF_PATH] = array(
    'access callback' => FALSE,
  );
  $items['admin/config/print/pdf'] = array(
    'title' => 'PDF',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('print_pdf_settings'),
    'access arguments'  => array('administer print'),
    'weight' => 3,
    'type' => MENU_LOCAL_TASK,
    'file' => 'print_pdf.admin.inc',
  );
  $items['admin/config/print/pdf/options'] = array(
    'title' => 'Options',
    'weight' => 1,
    'type' => MENU_DEFAULT_LOCAL_TASK,
  );
  $items['admin/config/print/pdf/strings'] = array(
    'title' => 'Text strings',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('print_pdf_strings_settings'),
    'access arguments'  => array('administer print'),
    'weight' => 2,
    'type' => MENU_LOCAL_TASK,
    'file' => 'print_pdf.admin.inc',
  );

  return $items;
}

/**
 * Implements hook_block_info().
 */
function print_pdf_block_info() {
      $block['print_pdf-top']['info'] = t('Most PDFd');
      $block['print_pdf-top']['cache'] = DRUPAL_CACHE_GLOBAL;
      return $block;
}

/**
 * Implements hook_block_view().
 */
function print_pdf_block_view($delta = 0) {
      switch ($delta) {
      case 'print_pdf-top':
        $block['subject'] = t('Most PDFd');
        $result = db_query_range("SELECT path FROM {print_pdf_page_counter} ORDER BY totalcount DESC", 0, 3)
                    ->fetchAll();
        if (count($result)) {
          $block['content'] = '<div class="item-list"><ul>';
          foreach ($result as $obj) {
            $block['content'] .= '<li>' . l(_print_get_title($obj->path), $obj->path) . '</li>';
          }
          $block['content'] .= '</ul></div>';
        }
        break;
      }
      return $block;
}

/**
 * Implements hook_requirements().
 */
function print_pdf_requirements($phase) {
  $requirements = array();
  $t = get_t();
  switch ($phase) {
    // At runtime, make sure that a PDF generation tool is selected
    case 'runtime':
      $print_pdf_pdf_tool = variable_get('print_pdf_pdf_tool', PRINT_PDF_PDF_TOOL_DEFAULT);
      if (empty($print_pdf_pdf_tool)) {
        $requirements['print_pdf_tool'] = array(
          'title' => $t('PDF generation library'),
          'value' => $t('No PDF tool selected'),
          'description' => $t('Please configure it in the <a href="@url">PDF settings page</a>.', array('@url' => url('admin/config/print/pdf'))),
          'severity' => REQUIREMENT_ERROR,
        );
      }
      else {
        if (!is_file($print_pdf_pdf_tool) || !is_readable($print_pdf_pdf_tool)) {
          $requirements['print_pdf_tool'] = array(
            'title' => $t('PDF generation tool'),
            'value' => $t('File not found'),
            'description' => $t('The currently selected PDF generation library (%file) is no longer accessible.', array('%file' => $print_pdf_pdf_tool)),
            'severity' => REQUIREMENT_ERROR,
          );
        }
        elseif (basename($print_pdf_pdf_tool) == 'dompdf_config.inc.php') {
          $directory = dirname($print_pdf_pdf_tool) . '/lib/fonts';
          if (!is_dir($directory) || !is_writable($directory)) {
            $requirements['print_pdf_tool'] = array(
              'title' => $t('DOMPDF font cache directory'),
              'value' => $t('Non-writable permissions'),
              'description' => $t('You must change the %fontdir permissions to be writable, as dompdf requires write-access to that directory.', array('%fontdir' => $directory)),
              'severity' => REQUIREMENT_ERROR,
            );
          }
        }
        elseif (substr(basename($print_pdf_pdf_tool, '.exe'), 0, 11) == 'wkhtmltopdf') {
          if (function_exists('is_executable') && !is_executable($print_pdf_pdf_tool)) {
            $requirements['print_pdf_tool'] = array(
              'title' => $t('wkhtmltopdf library'),
              'value' => $t('Non-executable permissions'),
              'description' => $t('You must modify the permissions of the wkhtmltopdf file (%file) to make it executable.', array('%file' => $print_pdf_pdf_tool)),
              'severity' => REQUIREMENT_ERROR,
            );
          }
          else {
            $version = _print_pdf_wkhtmltopdf_version();
            if (version_compare($version, '0.9.6', '<')) {
              $requirements['print_pdf_tool'] = array(
                'title' => $t('wkhtmltopdf library'),
                'value' => $t('Unsupported version'),
                'description' => $t('The currently selected version of wkhtmltopdf (@version) is not supported. Please update to a <a href="@url">newer version</a>.', array('@version' => $version, '@url' => url('http://code.google.com/p/wkhtmltopdf/'))),
                'severity' => REQUIREMENT_ERROR,
              );
            }
          }
        }
      }
      break;
  }
  return $requirements;
}

/**
 * Implements hook_node_view().
 */
function print_pdf_node_view($node, $build_mode) {
  $print_pdf_link_pos = variable_get('print_pdf_link_pos', array(PRINT_PDF_LINK_POS_DEFAULT => PRINT_PDF_LINK_POS_DEFAULT));
  $print_pdf_link_use_alias = variable_get('print_pdf_link_use_alias', PRINT_PDF_LINK_USE_ALIAS_DEFAULT);
  $allowed_type = print_pdf_link_allowed(array('type' => 'node', 'node' => $node, 'teaser' => ($build_mode == 'teaser')));
  if (($allowed_type) && !empty($print_pdf_link_pos['link'])) {
    drupal_add_css(drupal_get_path('module', 'print') . '/css/printlinks.css');
    $links = array();
    $format = theme('print_pdf_format_link');

    // Show book link
    if ($allowed_type === PRINT_ALLOW_BOOK_LINK) {
      $links['book_pdf'] = array('href' => PRINTPDF_PATH . '/book/export/html/' . $node->nid,
                                 'title' => $format['text'],
                                 'attributes' => $format['attributes'],
                                 'html' => $format['html'],
      );
    }
    elseif ($allowed_type === PRINT_ALLOW_NORMAL_LINK) {
      $query_arr = $_GET;
      if ('node' == 'comment') {
        $query_arr['comment'] = $node->cid;
      }
      $query = print_query_string_encode($query_arr, array('q'));
      if (empty($query)) $query = NULL;

      if ($print_pdf_link_use_alias) {
        $path = drupal_get_path_alias('node/' . $node->nid);
      }
      else {
        $path = $node->nid;
      }

      $links['print_pdf'] = array('href' => PRINTPDF_PATH . '/' . $path,
                                  'title' => $format['text'],
                                  'attributes' => $format['attributes'],
                                  'html' => $format['html'],
                                  'query' => $query,
      );
    }
    $node->content['links']['print_pdf'] = array(
      '#theme' => 'links',
      '#links' => $links,
      '#attributes' => array('class' => array('links', 'inline')),
    );
  }

  // Insert content corner links
  if ((!empty($print_pdf_link_pos['corner'])) && ($build_mode == 'full')) {
    $node->content['print_links']['#markup'] .= print_pdf_insert_link(NULL, $node);
  }
}

/**
 * Implements hook_help().
 */
function print_pdf_help($path, $arg) {
  $print_pdf_link_pos = variable_get('print_pdf_link_pos', array(PRINT_PDF_LINK_POS_DEFAULT => PRINT_PDF_LINK_POS_DEFAULT));
  if (($path !== 'node/%') && !(empty($print_pdf_link_pos['link']) && empty($print_pdf_link_pos['corner']))) {
    static $output = FALSE;

    if ($output === FALSE) {
      $output = TRUE;

      $link = print_pdf_insert_link();
      if ($link) {
        return "<span class='print-syslink'>$link</span>";
      }
    }
  }
}

/**
 * Implements hook_node_load().
 */
function print_pdf_node_load($nodes, $types) {
  foreach ($nodes as $node) {
    _print_pdf_set_node_fields($node);
  }
}

/**
 * Implements hook_node_insert().
 */
function print_pdf_node_insert($node) {
  if (user_access('administer print') || user_access('node-specific print configuration')) {
    if ($node->print_pdf_display === NULL) $node->print_pdf_display = variable_get('print_pdf_display_' . $node->type, PRINT_TYPE_SHOW_LINK_DEFAULT);
    if ($node->print_pdf_display_comment === NULL) $node->print_pdf_display_comment = variable_get('print_pdf_display_comment_' . $node->type, PRINT_TYPE_COMMENT_LINK_DEFAULT);
    if ($node->print_pdf_display_urllist === NULL) $node->print_pdf_display_urllist = variable_get('print_pdf_display_urllist_' . $node->type, PRINT_TYPE_URLLIST_DEFAULT);

    _print_pdf_node_conf_modify($node->nid, $node->print_pdf_display, $node->print_pdf_display_comment, $node->print_pdf_display_urllist);
  }
}

/**
 * Implements hook_node_update().
 */
function print_pdf_node_update($node) {
  if (user_access('administer print') || user_access('node-specific print configuration')) {
    if ($node->print_pdf_display === NULL) $node->print_pdf_display = variable_get('print_pdf_display_' . $node->type, PRINT_TYPE_SHOW_LINK_DEFAULT);
    if ($node->print_pdf_display_comment === NULL) $node->print_pdf_display_comment = variable_get('print_pdf_display_comment_' . $node->type, PRINT_TYPE_COMMENT_LINK_DEFAULT);
    if ($node->print_pdf_display_urllist === NULL) $node->print_pdf_display_urllist = variable_get('print_pdf_display_urllist_' . $node->type, PRINT_TYPE_URLLIST_DEFAULT);

    _print_pdf_node_conf_modify($node->nid, $node->print_pdf_display, $node->print_pdf_display_comment, $node->print_pdf_display_urllist);
  }
}

/**
 * Implements hook_node_delete().
 */
function print_pdf_node_delete($node) {
  db_delete('print_pdf_node_conf')
    ->condition('nid', $node->nid)
    ->execute();
  db_delete('print_pdf_page_counter')
    ->condition('path', 'node/' . $node->nid)
    ->execute();
}

/**
 * Implements hook_form_alter().
 */
function print_pdf_form_alter(&$form, &$form_state, $form_id) {
  // Add the node-type settings option to activate the PDF version link
  if ((user_access('administer print') || user_access('node-specific print configuration')) &&
      (($form_id == 'node_type_form') || !empty($form['#node_edit_form']))) {
    $form['print']['pdf_label'] = array(
      '#type' => 'markup',
      '#markup' => '<p><strong>' . t('PDF version') . '</strong></p>',
    );

    $form['print']['print_pdf_display'] = array(
      '#type' => 'checkbox',
      '#title' => t('Show link'),
    );
    $form['print']['print_pdf_display_comment'] = array(
      '#type' => 'checkbox',
      '#title' => t('Show link in individual comments'),
    );
    $form['print']['print_pdf_display_urllist'] = array(
      '#type' => 'checkbox',
      '#title' => t('Show Printer-friendly URLs list'),
    );

    if ($form_id == 'node_type_form') {
      $form['print']['print_pdf_display']['#default_value'] = variable_get('print_pdf_display_' . $form['#node_type']->type, PRINT_TYPE_SHOW_LINK_DEFAULT);
      $form['print']['print_pdf_display_comment']['#default_value'] = variable_get('print_pdf_display_comment_' . $form['#node_type']->type, PRINT_TYPE_COMMENT_LINK_DEFAULT);
      $form['print']['print_pdf_display_urllist']['#default_value'] = variable_get('print_pdf_display_urllist_' . $form['#node_type']->type, PRINT_TYPE_URLLIST_DEFAULT);
    }
    else {
      $node = $form['#node'];
      $form['print']['print_pdf_display']['#default_value'] = isset($node->print_pdf_display) ? $node->print_pdf_display : variable_get('print_pdf_display_' . $node->type, PRINT_TYPE_SHOW_LINK_DEFAULT);
      $form['print']['print_pdf_display_comment']['#default_value'] = isset($node->print_pdf_display_comment) ? $node->print_pdf_display_comment : variable_get('print_pdf_display_comment_' . $node->type, PRINT_TYPE_COMMENT_LINK_DEFAULT);
      $form['print']['print_pdf_display_urllist']['#default_value'] = isset($node->print_pdf_display_urllist) ? $node->print_pdf_display_urllist : variable_get('print_pdf_display_urllist_' . $node->type, PRINT_TYPE_URLLIST_DEFAULT);
    }
  }
}

/**
 * Auxiliary function to assign the per-node settings to the node object fields
 *
 * @param $node
 *   node to be modified
 */
function _print_pdf_set_node_fields(&$node) {
  if (isset($node->nid)) {
    $res = db_query("SELECT link, comments, url_list FROM {print_pdf_node_conf} WHERE nid = :nid", array(':nid' => $node->nid))
              ->fetch();
  }
  else {
    $res = FALSE;
  }
  $node->print_pdf_display = $res ? intval($res->link) : variable_get('print_pdf_display_' . $node->type, PRINT_TYPE_SHOW_LINK_DEFAULT);
  $node->print_pdf_display_comment = $res ? intval($res->comments) : variable_get('print_pdf_display_comment_' . $node->type, PRINT_TYPE_COMMENT_LINK_DEFAULT);
  $node->print_pdf_display_urllist = $res ? intval($res->url_list) : variable_get('print_pdf_display_urllist_' . $node->type, PRINT_TYPE_URLLIST_DEFAULT);
}

/**
 * Update the print_pdf_node_conf table to reflect the given attributes
 * If updating to the default values, delete the record.
 *
 * @param $nid
 *   value of the nid field (primary key)
 * @param $link
 *   value of the link field (0 or 1)
 * @param $comments
 *   value of the comments field (0 or 1)
 * @param $url_list
 *   value of the url_list field (0 or 1)
 */
function _print_pdf_node_conf_modify($nid, $link, $comments, $url_list) {
    db_merge('print_pdf_node_conf')
      ->key(array('nid' => $nid))
      ->fields(array(
        'link' => $link,
        'comments' => $comments,
        'url_list' => $url_list,
      ))
      ->execute();
}

/**
 * Format the PDF version link
 *
 * @return
 *   array of formatted attributes
 * @ingroup themeable
 */
function theme_print_pdf_format_link() {
  $print_pdf_link_class  = variable_get('print_pdf_link_class', PRINT_PDF_LINK_CLASS_DEFAULT);
  $print_pdf_content_disposition = variable_get('print_pdf_content_disposition', PRINT_PDF_CONTENT_DISPOSITION_DEFAULT);
  $print_pdf_show_link = variable_get('print_pdf_show_link', PRINT_PDF_SHOW_LINK_DEFAULT);
  $print_pdf_link_text = filter_xss(variable_get('print_pdf_link_text', t('PDF version')));

  $img = drupal_get_path('module', 'print') . '/icons/pdf_icon.gif';
  $title = t('Display a PDF version of this page.');
  $class = strip_tags($print_pdf_link_class);
  $new_window = ($print_pdf_content_disposition == 1);
  $format = _print_format_link_aux($print_pdf_show_link, $print_pdf_link_text, $img);

  return array('text' => $format['text'],
               'html' => $format['html'],
               'attributes' => print_fill_attributes($title, $class, $new_window),
              );
}

/**
 * Auxiliary function to display a formatted PDF version link
 *
 * Function made available so that developers may call this function from
 * their defined pages/blocks.
 *
 * @param $path
 *   path of the original page (optional). If not specified, the current URL
 *   is used
 * @param $node
 *   an optional node object, to be used in defining the path, if used, the
 *   path argument is irrelevant
 * @return
 *   string with the HTML link to the printer-friendly page
 */
function print_pdf_insert_link($path = NULL, $node = NULL) {
  if ($node !== NULL) {
    $nid = $node->nid;
    $path = 'node/' . $nid;
    $allowed_type = print_pdf_link_allowed(array('node' => $node));
  }
  else {
    if ($path === NULL) {
      $nid = preg_replace('!^node/!', '', $_GET['q']);
      $path = $_GET['q'];
    }
    else {
      $nid = NULL;
    }
    $allowed_type = print_pdf_link_allowed(array('path' => $path));
  }

  if ($allowed_type) {
    if ($nid !== NULL) {
      if ($allowed_type === PRINT_ALLOW_BOOK_LINK) {
        $path = 'book/export/html/' . $nid;
      }
      else {
        if (variable_get('print_pdf_link_use_alias', PRINT_PDF_LINK_USE_ALIAS_DEFAULT)) {
          $path = drupal_get_path_alias($path);
        }
        else {
          $path = $nid;
        }
      }
      $path = PRINTPDF_PATH . '/' . $path;
      $query = print_query_string_encode($_GET, array('q'));
      if (empty($query)) {
        $query = NULL;
      }
    }
    else {
      $query = NULL;
    }
    drupal_add_css(drupal_get_path('module', 'print') . '/css/printlinks.css');
    $format = theme('print_pdf_format_link');
    return '<span class="print_pdf">' . l($format['text'], $path, array('attributes' => $format['attributes'], 'query' => $query, 'absolute' => TRUE, 'html' => $format['html'])) . '</span>';
  }
  else {
    return FALSE;
  }
}

/**
 * Determine a the link to the PDF version is allowed depending on all possible settings
 *
 * @param $args
 *   array containing the possible parameters:
 *    teaser, node, type, path
 * @return
 *   FALSE if not allowed
 *   PRINT_ALLOW_NORMAL_LINK if a normal link is allowed
 *   PRINT_ALLOW_BOOK_LINK if a link is allowed in a book node
 */
function print_pdf_link_allowed($args) {
  $print_pdf_pdf_tool = variable_get('print_pdf_pdf_tool', PRINT_PDF_PDF_TOOL_DEFAULT);
  if ((!empty($args['teaser']) && !variable_get('print_pdf_link_teaser', PRINT_PDF_LINK_TEASER_DEFAULT))
      || !user_access('access PDF version') || (empty($print_pdf_pdf_tool))) {
    // If the teaser link is disabled or the user is not allowed
    return FALSE;
  }
  if (!empty($args['path'])) {
    $nid = preg_replace('!^node/!', '', drupal_get_normal_path($args['path']));
    if (is_numeric($nid)) {
      $args['node'] = node_load($nid);
    }
  }
  if (!empty($args['node'])) {
    static $node_type = FALSE;

    $node = $args['node'];
    if (isset($node->type)) {
      $node_type = $node->type;
    }
    // Node
    $print_pdf_node_link_visibility = variable_get('print_pdf_node_link_visibility', PRINT_PDF_NODE_LINK_VISIBILITY_DEFAULT);
    $print_pdf_node_link_pages = variable_get('print_pdf_node_link_pages', PRINT_PDF_NODE_LINK_PAGES_DEFAULT);

    if (!_print_page_match($print_pdf_node_link_visibility, "node/" . $node->nid, $print_pdf_node_link_pages)) {
      // Page not in visibility list
      return FALSE;
    }
    elseif (isset($args['type']) && ($args['type'] == 'comment') && isset($node_type)) {
      // Link is for a comment, return the configured setting
      $res = db_query("SELECT comments FROM {print_pdf_node_conf} WHERE nid = :nid", array(':nid' => $node->nid))
                ->fetch();
      $print_display_comment = $res ? intval($res->comments) : variable_get('print_pdf_display_comment_' . $node_type, PRINT_TYPE_COMMENT_LINK_DEFAULT);
      if ($print_display_comment) {
        return PRINT_ALLOW_NORMAL_LINK;
      }
    }
    else {
      // Node link
      if (!$node->print_pdf_display) {
        // Link for this node is disabled
        return FALSE;
      }
      elseif (isset($node->book)) {
        // Node is a book;
        $print_pdf_book_link = variable_get('print_pdf_book_link', PRINT_PDF_BOOK_LINK_DEFAULT);
        switch ($print_pdf_book_link) {
          case 1:
            if (user_access('access printer-friendly version')) {
              return PRINT_ALLOW_BOOK_LINK;
            }
            break;
          case 2:
            return PRINT_ALLOW_NORMAL_LINK;
        }
      }
      else {
        return PRINT_ALLOW_NORMAL_LINK;
      }
    }
  }
  else {
    // 'System' page
    $print_pdf_sys_link_visibility = variable_get('print_pdf_sys_link_visibility', PRINT_PDF_SYS_LINK_VISIBILITY_DEFAULT);
    $print_pdf_sys_link_pages = variable_get('print_pdf_sys_link_pages', PRINT_PDF_SYS_LINK_PAGES_DEFAULT);

    return _print_page_match($print_pdf_sys_link_visibility, $_GET['q'], $print_pdf_sys_link_pages);
  }
  return FALSE;
}

function _print_pdf_wkhtmltopdf_version() {
  $print_pdf_pdf_tool = variable_get('print_pdf_pdf_tool', PRINT_PDF_PDF_TOOL_DEFAULT);
  $descriptor = array(0 => array('pipe', 'r'), 1 => array('pipe', 'w'), 2 => array('pipe', 'w'));

  $cmd = realpath($print_pdf_pdf_tool) . ' --version';
  $process = proc_open($cmd, $descriptor, $pipes, NULL, NULL);
  if (is_resource($process)) {
    $out = preg_match('!.*?(\d+\.\d+\.\d+).*$!m', stream_get_contents($pipes[1]), $matches);
    fclose($pipes[0]);
    fclose($pipes[1]);
    fclose($pipes[2]);
    $retval = proc_terminate($process);
  }

  return ($matches[1]);
}