filefield.module

   1 <?php
   2 // $Id$
   3
   4 /**
   5  * @file
   6  * FileField: Defines a CCK file field type.
   7  *
   8  * Uses content.module to store the fid and field specific metadata,
   9  * and Drupal's {files} table to store the actual file data.
  10  */
  11
  12 include_once('field_file.inc');
  13
  14 /**
  15  * Implementation of hook_init().
  16  */
  17 function filefield_init() {
  18   // File hooks and callbacks may be used by any module.
  19   module_load_include('inc', 'filefield', 'filefield_widget');
  20   drupal_add_css(drupal_get_path('module', 'filefield') .'/filefield.css');
  21
  22   // Conditional module support.
  23   if (module_exists('token')) {
  24     module_load_include('inc', 'filefield', 'filefield.token');
  25   }
  26 }
  27
  28 /**
  29  * Implementation of hook_menu().
  30  */
  31 function filefield_menu() {
  32   $items = array();
  33
  34   $items['filefield/ahah/%/%/%'] = array(
  35     'page callback' => 'filefield_js',
  36     'page arguments' => array(2, 3, 4),
  37     'access callback' => 'filefield_edit_access',
  38     'access arguments' => array(3),
  39     'type' => MENU_CALLBACK,
  40   );
  41   return $items;
  42 }
  43
  44 /**
  45  * Implementation of hook_elements().
  46  * @todo: autogenerate element registry entries for widgets.
  47  */
  48 function filefield_elements() {
  49   $elements = array();
  50   $elements['filefield_widget'] =  array(
  51     '#input' => TRUE,
  52     '#columns' => array('fid', 'list', 'data'),
  53     '#process' => array('filefield_widget_process'),
  54     '#value_callback' => 'filefield_widget_value',
  55     '#element_validate' => array('filefield_widget_validate'),
  56     '#description' => t('Changes made to the attachments are not permanent until you save this post.'),
  57   );
  58   return $elements;
  59 }
  60
  61 /**
  62  * Implementation of hook_theme().
  63  * @todo: autogenerate theme registry entrys for widgets.
  64  */
  65 function filefield_theme() {
  66   return array(
  67     'filefield_file' => array(
  68       'arguments' => array('file' => NULL),
  69       'file' => 'filefield_formatter.inc',
  70     ),
  71     'filefield_icon' => array(
  72       'arguments' => array('file' => NULL),
  73       'file' => 'filefield.theme.inc',
  74     ),
  75     'filefield_widget' => array(
  76       'arguments' => array('element' => NULL),
  77       'file' => 'filefield_widget.inc',
  78     ),
  79     'filefield_widget_item' => array(
  80       'arguments' => array('element' => NULL),
  81       'file' => 'filefield_widget.inc',
  82     ),
  83     'filefield_widget_preview' => array(
  84       'arguments' => array('element' => NULL),
  85       'file' => 'filefield_widget.inc',
  86     ),
  87     'filefield_widget_file' => array(
  88       'arguments' => array('element' => NULL),
  89       'file' => 'filefield_widget.inc',
  90     ),
  91
  92
  93     'filefield_formatter_default' => array(
  94       'arguments' => array('element' => NULL),
  95       'file' => 'filefield_formatter.inc',
  96     ),
  97     'filefield_formatter_url_plain' => array(
  98       'arguments' => array('element' => NULL),
  99       'file' => 'filefield_formatter.inc',
 100     ),
 101     'filefield_formatter_path_plain' => array(
 102       'arguments' => array('element' => NULL),
 103       'file' => 'filefield_formatter.inc',
 104     ),
 105     'filefield_item' => array(
 106       'arguments' => array('file' => NULL, 'field' => NULL),
 107       'file' => 'filefield_formatter.inc',
 108     ),
 109     'filefield_file' => array(
 110       'arguments' => array('file' => NULL),
 111       'file' => 'filefield_formatter.inc',
 112     ),
 113
 114  );
 115 }
 116
 117 /**
 118  * Implementation of hook_file_download(). Yes, *that* hook that causes
 119  * any attempt for file upload module interoperability to fail spectacularly.
 120  */
 121 function filefield_file_download($file) {
 122   $file = file_create_path($file);
 123
 124   $result = db_query("SELECT * FROM {files} WHERE filepath = '%s'", $file);
 125   if (!$file = db_fetch_object($result)) {
 126     // We don't really care about this file.
 127     return;
 128   }
 129
 130   // Find out if any filefield contains this file, and if so, which field
 131   // and node it belongs to. Required for later access checking.
 132   $cck_files = array();
 133   foreach (content_fields() as $field) {
 134     if ($field['type'] == 'filefield' || $field['type'] == 'image') {
 135       $db_info = content_database_info($field);
 136       $table = $db_info['table'];
 137       $fid_column = $db_info['columns']['fid']['column'];
 138
 139       $columns = array('vid', 'nid');
 140       foreach ($db_info['columns'] as $property_name => $column_info) {
 141         $columns[] = $column_info['column'] .' AS '. $property_name;
 142       }
 143       $result = db_query("SELECT ". implode(', ', $columns) ."
 144                           FROM {". $table ."}
 145                           WHERE ". $fid_column ." = %d", $file->fid);
 146
 147       while ($content = db_fetch_array($result)) {
 148         $content['field'] = $field;
 149         $cck_files[$field['field_name']][$content['vid']] = $content;
 150       }
 151     }
 152   }
 153   // If no filefield item is involved with this file, we don't care about it.
 154   if (empty($cck_files)) {
 155     return;
 156   }
 157
 158   // If any node includes this file but the user may not view this field,
 159   // then deny the download.
 160   foreach ($cck_files as $field_name => $field_files) {
 161     if (!filefield_view_access($field_name)) {
 162       return -1;
 163     }
 164   }
 165
 166   // So the overall field view permissions are not denied, but if access is
 167   // denied for a specific node containing the file, deny the download as well.
 168   // It's probably a little too restrictive, but I can't think of a
 169   // better way at the moment. Input appreciated.
 170   // (And yeah, node access checks also include checking for 'access content'.)
 171   $nodes = array();
 172   foreach ($cck_files as $field_name => $field_files) {
 173     foreach ($field_files as $revision_id => $content) {
 174       // Checking separately for each revision is probably not the best idea -
 175       // what if 'view revisions' is disabled? So, let's just check for the
 176       // current revision of that node.
 177       if (isset($nodes[$content['nid']])) {
 178         continue; // don't check the same node twice
 179       }
 180       $node = node_load($content['nid']);
 181       if (!node_access('view', $node)) {
 182         // You don't have permission to view the node this file is attached to.
 183         return -1;
 184       }
 185       $nodes[$content['nid']] = $node;
 186     }
 187   }
 188
 189   // Well I guess you can see this file.
 190   $name = mime_header_encode($file->filename);
 191   $type = mime_header_encode($file->filemime);
 192   // Serve images and text inline for the browser to display rather than download.
 193   $disposition = ereg('^(text/|image/)', $file->filemime) ? 'inline' : 'attachment';
 194   return array(
 195     'Content-Type: '. $type .'; name='. $name,
 196     'Content-Length: '. $file->filesize,
 197     'Content-Disposition: '. $disposition .'; filename='. $name,
 198     'Cache-Control: private',
 199   );
 200 }
 201
 202 /**
 203  * Implementation of hook_form_alter().
 204  *
 205  * Set the appropriate attibutes to allow file uploads on the field settings
 206  * form.
 207  */
 208 function filefield_form_alter(&$form, $form_state, $form_id) {
 209   if ($form_id == 'content_field_edit_form' && isset($form['#field']) && $form['#field']['type'] == 'filefield') {
 210     $form['#attributes']['enctype'] = 'multipart/form-data';
 211   }
 212
 213   if (preg_match('/_node_form$/', $form_id)) {
 214     $form['#attributes']['enctype'] = 'multipart/form-data';
 215   }
 216 }
 217
 218 /**
 219  * Implementation of CCK's hook_field_info().
 220  */
 221 function filefield_field_info() {
 222   return array(
 223     'filefield' => array(
 224       'label' => 'File',
 225       'description' => t('Store an arbitrary file.'),
 226     ),
 227   );
 228 }
 229
 230 /**
 231  * Implementation of hook_field_settings().
 232  */
 233 function filefield_field_settings($op, $field) {
 234   $return = array();
 235
 236   module_load_include('inc', 'filefield', 'filefield_field');
 237   $op = str_replace(' ', '_', $op);
 238   // add filefield specific handlers...
 239   $function = 'filefield_field_settings_'. $op;
 240   if (function_exists($function)) {
 241     $result = $function($field);
 242     if (isset($result) && is_array($result)) {
 243       $return = $result;
 244     }
 245   }
 246
 247   // dynamically load widgets file and callbacks for other fields utilizing
 248   // filefield's hook_field_settings implementation.
 249   module_load_include('inc', $field['module'], $field['type'] .'_field');
 250   $function = $field['module'] .'_'. $field['type'] .'_field_settings_'. $op;
 251   if (function_exists($function)) {
 252     $result = $function($field);
 253     if (isset($result) && is_array($result)) {
 254       $return = array_merge($return, $result);
 255     }
 256   }
 257
 258   return $return;
 259
 260 }
 261
 262 /**
 263  * Implementtation of CCK's hook_field().
 264  */
 265 function filefield_field($op, $node, $field, &$items, $teaser, $page) {
 266   module_load_include('inc', 'filefield', 'filefield_field');
 267   $op = str_replace(' ', '_', $op);
 268   // add filefield specific handlers...
 269   $function = 'filefield_field_'. $op;
 270   if (function_exists($function)) {
 271     return $function($node, $field, $items, $teaser, $page);
 272   }
 273 }
 274
 275 /**
 276  * Implementation of CCK's hook_widget_settings().
 277  */
 278 function filefield_widget_settings($op, $widget) {
 279   switch ($op) {
 280     case 'form':
 281       return filefield_widget_settings_form($widget);
 282     case 'save':
 283       return filefield_widget_settings_save($widget);
 284   }
 285 }
 286
 287 /**
 288  * Implementation of hook_widget().
 289  */
 290 function filefield_widget(&$form, &$form_state, $field, $items, $delta = 0) {
 291   // CCK doesn't give a validate callback at the field level...
 292   // and FAPI's #require is naieve to complex structures...
 293   // we validate at the field level ourselves.
 294   if (empty($form['#validate']) || !in_array('filefield_node_form_validate', $form['#validate'])) {
 295     $form['#validate'][] = 'filefield_node_form_validate';
 296   }
 297   if (empty($form['#submit']) || !in_array('filefield_node_form_submit', $form['#submit'])) {
 298     $form['#submit'][] = 'filefield_node_form_submit';
 299   }
 300   $form['#attributes'] = array('enctype' => 'multipart/form-data');
 301
 302   module_load_include('inc', 'filefield', 'field_widget');
 303   module_load_include('inc', $field['widget']['module'], $field['widget']['module'] .'_widget');
 304
 305   $item = array('fid' => 0, 'list' => $field['list_default'], 'data' => array('description' => ''));
 306   if (isset($items[$delta])) {
 307     $item = array_merge($item, $items[$delta]);
 308   }
 309   $element = array(
 310     '#title' => $field['widget']['label'],
 311     '#type' => $field['widget']['type'],
 312     '#default_value' => $item,
 313     '#upload_validators' => filefield_widget_upload_validators($field),
 314   );
 315
 316   return $element;
 317 }
 318
 319 /**
 320  * Get the upload validators for a file field.
 321  *
 322  * @param $field
 323  *   A CCK field array.
 324  * @return
 325  *   An array suitable for passing to file_save_upload() or the file field
 326  *   element's '#upload_validators' property.
 327  */
 328 function filefield_widget_upload_validators($field) {
 329   $max_filesize = parse_size(file_upload_max_size());
 330   if (!empty($field['widget']['max_filesize_per_file']) && parse_size($field['widget']['max_filesize_per_file']) < $max_filesize) {
 331     $max_filesize = parse_size($field['widget']['max_filesize_per_file']);
 332   }
 333
 334   $validators = array(
 335     // associate the field to the file on validation.
 336     'filefield_validate_associate_field' => array($field),
 337     'filefield_validate_size' => array($max_filesize),
 338     // Override core since it excludes uid 1 on the extension check.
 339     // Filefield only excuses uid 1 of quota requirements.
 340     'filefield_validate_extensions' => array($field['widget']['file_extensions']),
 341   );
 342   return $validators;
 343 }
 344
 345 /**
 346  * Implementation of CCK's hook_content_is_empty().
 347  *
 348  * The result of this determines whether content.module will save the value of
 349  * the field. Note that content module has some interesting behaviors for empty
 350  * values. It will always save at least one record for every node revision,
 351  * even if the values are all NULL. If it is a multi-value field with an
 352  * explicit limit, CCK will save that number of empty entries.
 353  */
 354 function filefield_content_is_empty($item, $field) {
 355   return empty($item['fid']) || (int)$item['fid'] == 0;
 356 }
 357
 358 /**
 359  * Implementation of CCK's hook_widget_info().
 360  */
 361 function filefield_widget_info() {
 362   return array(
 363     'filefield_widget' => array(
 364       'label' => t('File Upload'),
 365       'field types' => array('filefield'),
 366       'multiple values' => CONTENT_HANDLE_CORE,
 367       'callbacks' => array('default value' => CONTENT_CALLBACK_CUSTOM),
 368       'description' => t('A plain file upload widget.'),
 369     ),
 370   );
 371 }
 372
 373 /**
 374  * Implementation of CCK's hook_field_formatter_info().
 375  */
 376 function filefield_field_formatter_info() {
 377   return array(
 378     'default' => array(
 379       'label' => t('Generic files'),
 380       'field types' => array('filefield'),
 381       'multiple values' => CONTENT_HANDLE_CORE,
 382       'description' => t('Displays all kinds of files with an icon and a linked file description.'),
 383     ),
 384     'path_plain' => array(
 385       'label' => t('Path to file'),
 386       'field types' => array('filefield'),
 387       'description' => t('Displays the file system path to the file.'),
 388     ),
 389     'url_plain' => array(
 390       'label' => t('URL to file'),
 391       'field types' => array('filefield'),
 392       'description' => t('Displays a full URL to the file.'),
 393     ),
 394   );
 395 }
 396
 397 /**
 398  * Determine the most appropriate icon for the given file's mimetype.
 399  *
 400  * @param $file
 401  *   A file object.
 402  * @return
 403  *   The URL of the icon image file, or FALSE if no icon could be found.
 404  */
 405 function filefield_icon_url($file) {
 406   include_once(drupal_get_path('module', 'filefield') .'/filefield.theme.inc');
 407   return _filefield_icon_url($file);
 408 }
 409
 410 /**
 411  * Access callback for the JavaScript upload and deletion AHAH callbacks.
 412  *
 413  * The content_permissions module provides nice fine-grained permissions for
 414  * us to check, so we can make sure that the user may actually edit the file.
 415  */
 416 function filefield_edit_access($field_name) {
 417   if (module_exists('content_permissions')) {
 418     return user_access('edit '. $field_name);
 419   }
 420   // No content permissions to check, so let's fall back to a more general permission.
 421   return user_access('access content');
 422 }
 423
 424 /**
 425  * Access callback that checks if the current user may view the filefield.
 426  */
 427 function filefield_view_access($field_name) {
 428   if (module_exists('content_permissions')) {
 429     return user_access('view '. $field_name);
 430   }
 431   // No content permissions to check, so let's fall back to a more general permission.
 432   return user_access('access content');
 433 }
 434
 435 /**
 436  * Menu callback; Shared AHAH callback for uploads and deletions.
 437  *
 438  * This rebuilds the form element for a particular field item. As long as the
 439  * form processing is properly encapsulated in the widget element the form
 440  * should rebuild correctly using FAPI without the need for additional callbacks
 441  * or processing.
 442  */
 443 function filefield_js($type_name, $field_name, $delta) {
 444   $field = content_fields($field_name, $type_name);
 445
 446   if (empty($field) || empty($_POST['form_build_id'])) {
 447     // Invalid request.
 448     print drupal_to_js(array('data' => ''));
 449     exit;
 450   }
 451
 452   // Build the new form.
 453   $form_state = array('submitted' => FALSE);
 454   $form_build_id = $_POST['form_build_id'];
 455   $form = form_get_cache($form_build_id, $form_state);
 456
 457   if (!$form) {
 458     // Invalid form_build_id.
 459     print drupal_to_js(array('data' => ''));
 460     exit;
 461   }
 462
 463   // Build the form. This calls the file field's #value_callback function and
 464   // saves the uploaded file. Since this form is already marked as cached
 465   // (the #cache property is TRUE), the cache is updated automatically and we
 466   // don't need to call form_set_cache().
 467   $args = $form['#parameters'];
 468   $form_id = array_shift($args);
 469   $form['#post'] = $_POST;
 470   $form = form_builder($form_id, $form, $form_state);
 471
 472   // Update the cached form with the new element at the right place in the form.
 473   if (module_exists('fieldgroup') && ($group_name = _fieldgroup_field_get_group($type_name, $field_name))) {
 474     if (isset($form['#multigroups']) && isset($form['#multigroups'][$group_name][$field_name])) {
 475       $form_element = $form[$group_name][$delta][$field_name];
 476     }
 477     else {
 478       $form_element = $form[$group_name][$field_name][$delta];
 479     }
 480   }
 481   else {
 482     $form_element = $form[$field_name][$delta];
 483   }
 484
 485   if (isset($form_element['_weight'])) {
 486     unset($form_element['_weight']);
 487   }
 488
 489   $output = drupal_render($form_element);
 490
 491   // AHAH is not being nice to us and doesn't know the "other" button (that is,
 492   // either "Upload" or "Delete") yet. Which in turn causes it not to attach
 493   // AHAH behaviours after replacing the element. So we need to tell it first.
 494
 495   // Loop through the JS settings and find the settings needed for our buttons.
 496   $javascript = drupal_add_js(NULL, NULL);
 497   $filefield_ahah_settings = array();
 498   if (isset($javascript['setting'])) {
 499     foreach ($javascript['setting'] as $settings) {
 500       if (isset($settings['ahah'])) {
 501         foreach ($settings['ahah'] as $id => $ahah_settings) {
 502           if (strpos($id, 'filefield-upload') || strpos($id, 'filefield-remove')) {
 503             $filefield_ahah_settings[$id] = $ahah_settings;
 504           }
 505         }
 506       }
 507     }
 508   }
 509
 510   // Add the AHAH settings needed for our new buttons.
 511   if (!empty($filefield_ahah_settings)) {
 512     $output .= '<script type="text/javascript">jQuery.extend(Drupal.settings.ahah, '. drupal_to_js($filefield_ahah_settings) .');</script>';
 513   }
 514
 515   $output = theme('status_messages') . $output;
 516
 517   // For some reason, file uploads don't like drupal_json() with its manual
 518   // setting of the text/javascript HTTP header. So use this one instead.
 519   $GLOBALS['devel_shutdown'] = FALSE;
 520   print drupal_to_js(array('status' => TRUE, 'data' => $output));
 521   exit;
 522 }
 523
 524 /**
 525  * Implementation of hook_file_references().
 526  */
 527 function filefield_file_references($file) {
 528   $references = 0;
 529   foreach (content_fields() as $field) {
 530     if ($field['type'] != 'filefield') {
 531       continue;
 532     }
 533     $references += field_file_references($file, $field);
 534   }
 535   return array('filefield' => $references);
 536 }
 537
 538 /**
 539  * Implementation of hook_file_delete().
 540  */
 541 function filefield_file_delete($file) {
 542   // foreach  field... remove items referencing $file.
 543 }
 544
 545 /**
 546  * An #upload_validators callback. Check the file matches an allowed extension.
 547  *
 548  * If the mimedetect module is available, this will also validate that the
 549  * content of the file matches the extension. User #1 is included in this check.
 550  *
 551  * @param $file
 552  *   A Drupal file object.
 553  * @param $extensions
 554  *   A string with a space separated list of allowed extensions.
 555  * @return
 556  *   An array of any errors cause by this file if it failed validation.
 557  */
 558 function filefield_validate_extensions($file, $extensions) {
 559   global $user;
 560   $errors = array();
 561
 562   if (!empty($extensions)) {
 563     $regex = '/\.('. ereg_replace(' +', '|', preg_quote($extensions)) .')$/i';
 564     $matches = array();
 565     if (preg_match($regex, $file->filename, $matches)) {
 566       $extension = $matches[1];
 567       // If the extension validates, check that the mimetype matches.
 568       if (module_exists('mimedetect')) {
 569         $type = mimedetect_mime($file);
 570         if ($type != $file->filemime) {
 571           $errors[] = t('The file contents (@type) do not match its extension (@extension).', array('@type' => $type, '@extension' => $extension));
 572         }
 573       }
 574     }
 575     else {
 576       $errors[] = t('Only files with the following extensions are allowed: %files-allowed.', array('%files-allowed' => $extensions));
 577     }
 578   }
 579
 580   return $errors;
 581 }
 582
 583 /**
 584  * Help text automatically appended to fields that have extension validation.
 585  */
 586 function filefield_validate_extensions_help($extensions) {
 587   if (!empty($extensions)) {
 588     return t('Allowed Extensions: %ext', array('%ext' => $extensions));
 589   }
 590   else {
 591     return '';
 592   }
 593 }
 594
 595 /**
 596  * An #upload_validators callback. Check the file size does not exceed a limit.
 597  *
 598  * @param $file
 599  *   A Drupal file object.
 600  * @param $file_limit
 601  *   An integer value limiting the maximum file size in bytes.
 602  * @param $file_limit
 603  *   An integer value limiting the maximum size in bytes a user can upload on
 604  *   the entire site.
 605  * @return
 606  *   An array of any errors cause by this file if it failed validation.
 607  */
 608 function filefield_validate_size($file, $file_limit = 0, $user_limit = 0) {
 609   global $user;
 610
 611   $errors = array();
 612
 613   if ($file_limit && $file->filesize > $file_limit) {
 614     $errors[] = t('The file is %filesize exceeding the maximum file size of %maxsize.', array('%filesize' => format_size($file->filesize), '%maxsize' => format_size($file_limit)));
 615   }
 616
 617   // Bypass user limits for uid  = 1.
 618   if ($user->uid != 1) {
 619     $total_size = file_space_used($user->uid) + $file->filesize;
 620     if ($user_limit && $total_size > $user_limit) {
 621       $errors[] = t('The file is %filesize which would exceed your disk quota of %quota.', array('%filesize' => format_size($file->filesize), '%quota' => format_size($user_limit)));
 622     }
 623   }
 624   return $errors;
 625 }
 626
 627 /**
 628  * Automatic help text appended to fields that have file size validation.
 629  */
 630 function filefield_validate_size_help($size) {
 631   return t('Maximum Filesize: %size', array('%size' => format_size(parse_size($size))));
 632 }
 633
 634 /**
 635  * An #upload_validators callback. Check an image resolution.
 636  *
 637  * @param $file
 638  *   A Drupal file object.
 639  * @param $max_size
 640  *   A string in the format WIDTHxHEIGHT. If the image is larger than this size
 641  *   the image will be scaled to fit within these dimensions.
 642  * @param $min_size
 643  *   A string in the format WIDTHxHEIGHT. If the image is smaller than this size
 644  *   a validation error will be returned.
 645  * @return
 646  *   An array of any errors cause by this file if it failed validation.
 647  */
 648 function filefield_validate_image_resolution(&$file, $maximum_dimensions = 0, $minimum_dimensions = 0) {
 649   $errors = array();
 650
 651   // Check first that the file is an image.
 652   if ($info = image_get_info($file->filepath)) {
 653     if ($maximum_dimensions) {
 654       // Check that it is smaller than the given dimensions.
 655       list($width, $height) = explode('x', $maximum_dimensions);
 656       if ($info['width'] > $width || $info['height'] > $height) {
 657         // Try to resize the image to fit the dimensions.
 658         if (image_get_toolkit() && image_scale($file->filepath, $file->filepath, $width, $height)) {
 659           drupal_set_message(t('The image was resized to fit within the maximum allowed dimensions of %dimensions pixels.', array('%dimensions' => $maximum_dimensions)));
 660
 661           // Clear the cached filesize and refresh the image information.
 662           clearstatcache();
 663           $info = image_get_info($file->filepath);
 664           $file->filesize = $info['file_size'];
 665         }
 666         else {
 667           $errors[] = t('The image is too large; the maximum dimensions are %dimensions pixels.', array('%dimensions' => $maximum_dimensions));
 668         }
 669       }
 670     }
 671
 672     if ($minimum_dimensions) {
 673       // Check that it is larger than the given dimensions.
 674       list($width, $height) = explode('x', $minimum_dimensions);
 675       if ($info['width'] < $width || $info['height'] < $height) {
 676         $errors[] = t('The image is too small; the minimum dimensions are %dimensions pixels.', array('%dimensions' => $minimum_dimensions));
 677       }
 678     }
 679   }
 680
 681   return $errors;
 682 }
 683
 684 /**
 685  * Automatic help text appended to fields that have image resolution validation.
 686  */
 687 function filefield_validate_image_resolution_help($max_size = '0', $min_size = '0') {
 688   if (!empty($max_size)) {
 689     if (!empty($min_size)) {
 690       if ($max_size == $min_size) {
 691         return t('Images must be exactly @min_size pixels', array('@min_size' => $min_size));
 692       }
 693       else {
 694         return t('Images must be between @min_size pixels and @max_size', array('@max_size' => $max_size, '@min_size' => $min_size));
 695       }
 696     }
 697     else {
 698       if (image_get_toolkit()) {
 699         return t('Images larger than @max_size pixels will be scaled', array('@max_size' => $max_size));
 700       }
 701       else {
 702         return t('Images must be smaller than @max_size pixels', array('@max_size' => $max_size));
 703       }
 704     }
 705   }
 706   if (!empty($min_size)) {
 707     return t('Images must be larger than @max_size pixels', array('@max_size' => $min_size));
 708   }
 709 }
 710
 711
 712 /**
 713  * An #upload_validators callback. Check that a file is an image.
 714  *
 715  * This check should allow any image that PHP can identify, including png, jpg,
 716  * gif, tif, bmp, psd, swc, iff, jpc, jp2, jpx, jb2, xbm, and wbmp.
 717  *
 718  * This check should be combined with filefield_validate_extensions() to ensure
 719  * only web-based images are allowed, however it provides a better check than
 720  * extension checking alone if the mimedetect module is not available.
 721  *
 722  * @param $file
 723  *   A Drupal file object.
 724  * @return
 725  *   An array of any errors cause by this file if it failed validation.
 726  */
 727 function filefield_validate_is_image(&$file) {
 728   $errors = array();
 729   $info = image_get_info($file->filepath);
 730   if (!$info || empty($info['extension'])) {
 731     $errors[] = t('The file is not a known image format.');
 732   }
 733   return $errors;
 734 }
 735
 736 /**
 737  * An #upload_validators callback. Add the field to the file object.
 738  *
 739  * This validation function adds the field to the file object for later
 740  * use in field aware modules implementing hook_file. It's not truly a
 741  * validation at all, rather a convient way to add properties to the uploaded
 742  * file.
 743  */
 744 function filefield_validate_associate_field(&$file, $field) {
 745   $file->field = $field;
 746   return array();
 747 }