field.module 27.5 KB
Newer Older
1
2
3
4
<?php
// $Id$
/**
 * @file
5
 * Attach custom data fields to Drupal objects.
6
7
 */

8
/*
9
10
11
 * Load all public Field API functions. Drupal currently has no
 * mechanism for auto-loading core APIs, so we have to load them on
 * every page request.
12
 */
13
14
15
16
17
18
module_load_include('inc', 'field', 'field.crud');
module_load_include('inc', 'field', 'field.default');
module_load_include('inc', 'field', 'field.info');
module_load_include('inc', 'field', 'field.multilingual');
module_load_include('inc', 'field', 'field.attach');
module_load_include('inc', 'field', 'field.form');
19

20
21
22
23
24
25
26
/**
 * @defgroup field Field API
 * @{
 * Attach custom data fields to Drupal objects.
 *
 * The Field API allows custom data fields to be attached to Drupal
 * objects and takes care of storing, loading, editing, and rendering
27
 * field data. Any object type (node, user, etc.) can use the Field
28
 * API to make itself "fieldable" and thus allow fields to be attached
29
 * to it. Other modules can provide a user interface for managing custom
30
 * fields via a web browser as well as a wide and flexible variety of
31
32
33
34
 * data type, form element, and display format capabilities.
 *
 * - @link field_structs Data structures: Field, Instance, Bundle @endlink.
 *
35
36
 * - @link field_types Field Types API @endlink. Defines field types,
 *   widget types, and display formatters. Field modules use this API
37
38
39
 *   to provide field types like Text and Node Reference along with the
 *   associated form elements and display formatters.
 *
40
 * - @link field_crud Field CRUD API @endlink. Create, updates, and
41
42
 *   deletes fields, bundles (a.k.a. "content types"), and instances.
 *   Modules use this API, often in hook_install(), to create
43
 *   custom data structures.
44
 *
45
46
 * - @link field_attach Field Attach API @endlink. Connects object
 *   types to the Field API. Field Attach API functions load, store,
47
 *   generate Form API structures, display, and perform a variety of
48
49
50
51
 *   other functions for field data connected to individual objects.
 *   Fieldable object types like node and user use this API to make
 *   themselves fieldable.
 *
52
 * - @link field_info Field Info API @endlink. Exposes information
53
54
55
 *   about all fields, instances, widgets, and related information
 *   defined by or with the Field API.
 *
56
57
 * - @link field_storage Field Storage API @endlink. Provides a
 *   pluggable back-end storage system for actual field data. The
58
59
 *   default implementation, field_sql_storage.module, stores field data
 *   in the local SQL database.
60
 *
61
62
63
 * - @link field_purge Field API bulk data deletion @endlink. Cleans
 *   up after bulk deletion operations such as field_delete_field()
 *   and field_delete_instance().
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
 */

/**
 * Value for $field['cardinality'] property to indicate it can hold an
 * unlimited number of values.
 */
define('FIELD_CARDINALITY_UNLIMITED', -1);

/**
 * TODO
 */
define('FIELD_BEHAVIOR_NONE', 0x0001);
/**
 * TODO
 */
define('FIELD_BEHAVIOR_DEFAULT', 0x0002);
/**
 * TODO
 */
define('FIELD_BEHAVIOR_CUSTOM', 0x0004);

/**
 * Age argument for loading the most recent version of an object's
 * field data with field_attach_load().
 */
define('FIELD_LOAD_CURRENT', 'FIELD_LOAD_CURRENT');
/**
 * Age argument for loading the version of an object's field data
 * specified in the object with field_attach_load().
 */
define('FIELD_LOAD_REVISION', 'FIELD_LOAD_REVISION');

96
97
98
/**
 * @name Field query flags
 * @{
99
 * Flags for field_attach_query().
100
101
 */

102
103
104
105
106
107
/**
 * Limit argument for field_attach_query() to request all available
 * objects instead of a limited number.
 */
define('FIELD_QUERY_NO_LIMIT', 'FIELD_QUERY_NO_LIMIT');

108
/**
109
110
 * Cursor return value for field_attach_query() to indicate that no
 * more data is available.
111
 */
112
define('FIELD_QUERY_COMPLETE', 'FIELD_QUERY_COMPLETE');
113
114
115
116

/**
 * @} End of "Field query flags".
 */
117
118
119
120
121
122
123
124
125

/**
 * Base class for all exceptions thrown by Field API functions.
 *
 * This class has no functionality of its own other than allowing all
 * Field API exceptions to be caught by a single catch block.
 */
class FieldException extends Exception {}

126
127
128
129
130
/**
 * Exception class thrown by hook_field_update_forbid().
 */
class FieldUpdateForbiddenException extends FieldException {}

131
/**
132
 * Implements hook_flush_caches().
133
134
135
136
137
138
 */
function field_flush_caches() {
  return array('cache_field');
}

/**
139
 * Implements hook_help().
140
141
142
143
 */
function field_help($path, $arg) {
  switch ($path) {
    case 'admin/help#field':
144
145
146
147
148
149
      $output = '';
      $output .= '<h3>' . t('About') . '</h3>';
      $output .= '<p>' . t('The Field module allows custom data fields to be attached to Drupal <em>objects</em> (content nodes, users, taxonomy vocabularies, etc.) and takes care of storing, loading, editing, and rendering field data. Most users will not interact with the Field module directly, but will instead use the <a href="@field-ui-help">Field UI module</a> user interface. Module developers can use the Field API to make new objects "fieldable" and thus allow fields to be attached to their objects. For more information, see the online handbook entry for <a href="@field">Field module</a>.', array('@field-ui-help' => url('admin/help/field_ui'), '@field' => 'http://drupal.org/handbook/modules/field')) . '</p>';
      $output .= '<h3>' . t('Uses') . '</h3>';
      $output .= '<dl>';
      $output .= '<dt>' . t('Enabling field types') . '</dt>';
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
      $output .= '<dd>' . t('The Field module provides the infrastructure for fields and field attachment; the field types and input widgets themselves are provided by additional modules. Some of the modules are required; the optional modules can be enabled from the <a href="@modules">Modules administration page</a>. Drupal core includes the following field type modules: Number (required), Text (required), List (required), Taxonomy (optional), Image (optional), and File (optional); the required Options module provides input widgets for other field modules. Additional fields and widgets may be provided by contributed modules, which you can find in the <a href="@contrib">contributed module section of Drupal.org</a>. Currently enabled field and input widget modules:', array('@modules' => url('admin/config/modules'), '@contrib' => 'http://drupal.org/project/modules', '@options' => url('admin/help/options')));

      // Make a list of all widget and field modules currently enabled, in
      // order by displayed module name (module names are not translated).
      $items = array();
      $info = system_get_info('module');
      $modules = array_merge(module_implements('field_info'), module_implements('field_widget_info'));
      $modules = array_unique($modules);
      sort($modules);
      foreach ($modules as $module) {
        $display = $info[$module]['name'];
        if (module_hook($module, 'help')) {
          $items['items'][] = l($display, 'admin/help/' . $module);
        }
        else {
          $items['items'][] = $display;
        }
      }
      $output .= theme('item_list', $items) . '</dd>';
      $output .= '<dt>' . t('Managing field data storage') . '</dt>';
      $output .= '<dd>' . t('Developers of field modules can either use the default <a href="@sql-store">Field SQL storage module</a> to store data for their fields, or a contributed or custom module developed using the <a href="@storage-api">field storage API</a>.', array('@storage-api' => 'http://api.drupal.org/api/group/field_storage/7', '@sql-store' => url('admin/help/field_sql_storage'))) . '</dd>';
171
      $output .= '</dl>';
172
173
174
175
176
      return $output;
  }
}

/**
177
 * Implements hook_theme().
178
179
180
 */
function field_theme() {
  $path = drupal_get_path('module', 'field') . '/theme';
181
  $items = array(
182
183
    'field' => array(
      'template' => 'field',
184
      'render element' => 'element',
185
186
187
      'path' => $path,
    ),
    'field_multiple_value_form' => array(
188
      'render element' => 'element',
189
190
    ),
  );
191

192
  return $items;
193
194
}

195
/**
196
 * Implements hook_cron().
197
198
199
200
201
202
203
204
 *
 * Purges some deleted Field API data, if any exists.
 */
function field_cron() {
  $limit = variable_get('field_purge_batch_size', 10);
  field_purge_batch($limit);
}

205
/**
206
 * Implements hook_modules_installed().
207
208
209
210
211
212
 */
function field_modules_installed($modules) {
  field_cache_clear();
}

/**
213
 * Implements hook_modules_uninstalled().
214
215
216
217
218
219
220
221
222
223
 */
function field_modules_uninstalled($modules) {
  module_load_include('inc', 'field', 'field.crud');
  foreach ($modules as $module) {
    // TODO D7: field_module_delete is not yet implemented
    // field_module_delete($module);
  }
}

/**
224
 * Implements hook_modules_enabled().
225
226
227
228
229
230
231
232
233
 */
function field_modules_enabled($modules) {
  foreach ($modules as $module) {
    field_associate_fields($module);
  }
  field_cache_clear();
}

/**
234
 * Implements hook_modules_disabled().
235
236
237
238
239
240
241
 */
function field_modules_disabled($modules) {
  foreach ($modules as $module) {
    db_update('field_config')
      ->fields(array('active' => 0))
      ->condition('module', $module)
      ->execute();
242
243
244
245
    db_update('field_config')
      ->fields(array('storage_active' => 0))
      ->condition('storage_module', $module)
      ->execute();
246
247
248
249
250
251
252
253
254
255
256
    field_cache_clear(TRUE);
  }
}

/**
 * Allows a module to update the database for fields and columns it controls.
 *
 * @param string $module
 *   The name of the module to update on.
 */
function field_associate_fields($module) {
257
258
259
260
261
262
263
264
  // Associate field types.
  $field_types =(array) module_invoke($module, 'field_info');
  foreach ($field_types as $name => $field_info) {
    watchdog('field', 'Updating field type %type with module %module.', array('%type' => $name, '%module' => $module));
    db_update('field_config')
      ->fields(array('module' => $module, 'active' => 1))
      ->condition('type', $name)
      ->execute();
265
  }
266
267
268
269
270
271
272
273
274
  // Associate storage backends.
  $storage_types = (array) module_invoke($module, 'field_storage_info');
  foreach ($storage_types as $name => $storage_info) {
    watchdog('field', 'Updating field storage %type with module %module.', array('%type' => $name, '%module' => $module));
    db_update('field_config')
      ->fields(array('storage_module' => $module, 'storage_active' => 1))
      ->condition('storage_type', $name)
      ->execute();
  }
275
276
}

277
278
279
280
281
282
283
284
285
286
287
/**
 * Helper function to get the default value for a field on an object.
 *
 * @param $obj_type
 *   The type of $object; e.g. 'node' or 'user'.
 * @param $object
 *   The object for the operation.
 * @param $field
 *   The field structure.
 * @param $instance
 *   The instance structure.
288
289
 * @param $langcode
 *   The field language to fill-in with the default value.
290
 */
291
function field_get_default_value($obj_type, $object, $field, $instance, $langcode = NULL) {
292
293
294
  $items = array();
  if (!empty($instance['default_value_function'])) {
    $function = $instance['default_value_function'];
295
    if (function_exists($function)) {
296
      $items = $function($obj_type, $object, $field, $instance, $langcode);
297
298
299
300
301
302
303
304
    }
  }
  elseif (!empty($instance['default_value'])) {
    $items = $instance['default_value'];
  }
  return $items;
}

305
/**
306
 * Helper function to filter out empty field values.
307
 *
308
309
310
311
 * @param $field
 *   The field definition.
 * @param $items
 *   The field values to filter.
312
 *
313
314
315
 * @return
 *   The array of items without empty field values. The function also renumbers
 *   the array keys to ensure sequential deltas.
316
 */
317
function _field_filter_items($field, $items) {
318
  $function = $field['module'] . '_field_is_empty';
319
  function_exists($function);
320
  foreach ((array) $items as $delta => $item) {
321
    // Explicitly break if the function is undefined.
322
323
    if ($function($item, $field)) {
      unset($items[$delta]);
324
325
    }
  }
326
  return array_values($items);
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
}

/**
 * Helper function to sort items in a field according to
 * user drag-n-drop reordering.
 */
function _field_sort_items($field, $items) {
  if (($field['cardinality'] > 1 || $field['cardinality'] == FIELD_CARDINALITY_UNLIMITED) && isset($items[0]['_weight'])) {
    usort($items, '_field_sort_items_helper');
    foreach ($items as $delta => $item) {
      if (is_array($items[$delta])) {
        unset($items[$delta]['_weight']);
      }
    }
  }
  return $items;
}

/**
 * Sort function for items order.
 * (copied form element_sort(), which acts on #weight keys)
 */
function _field_sort_items_helper($a, $b) {
  $a_weight = (is_array($a) && isset($a['_weight'])) ? $a['_weight'] : 0;
  $b_weight = (is_array($b) && isset($b['_weight'])) ? $b['_weight'] : 0;
  if ($a_weight == $b_weight) {
    return 0;
  }
  return ($a_weight < $b_weight) ? -1 : 1;
}

/**
 * Same as above, using ['_weight']['#value']
 */
function _field_sort_items_value_helper($a, $b) {
  $a_weight = (is_array($a) && isset($a['_weight']['#value'])) ? $a['_weight']['#value'] : 0;
  $b_weight = (is_array($b) && isset($b['_weight']['#value'])) ? $b['_weight']['#value'] : 0;
  if ($a_weight == $b_weight) {
    return 0;
  }
  return ($a_weight < $b_weight) ? -1 : 1;
}

370
371
372
/**
 * Registry of pseudo-field components in a given bundle.
 *
373
374
375
 * @param $obj_type
 *   The type of $object; e.g. 'node' or 'user'.
 * @param $bundle
376
377
378
379
 *   The bundle name.
 * @return
 *   The array of pseudo-field elements in the bundle.
 */
380
function field_extra_fields($obj_type, $bundle) {
381
382
383
  $info = &drupal_static(__FUNCTION__, array());

  if (empty($info)) {
384
385
386
387
388
389
390
391
392
393
394
395
    $info = (array) module_invoke_all('field_extra_fields');
    drupal_alter('field_extra_fields', $info);

    // Add saved weights. The array is keyed by object type, bundle and
    // element name.
    $extra_weights = variable_get('field_extra_weights', array());
    foreach ($extra_weights as $obj_type_name => $bundles) {
      foreach ($bundles as $bundle_name => $weights) {
        foreach ($weights as $key => $value) {
          if (isset($info[$obj_type_name][$bundle_name][$key])) {
            $info[$obj_type_name][$bundle_name][$key]['weight'] = $value;
          }
396
397
398
399
        }
      }
    }
  }
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420

  return isset($info[$obj_type][$bundle]) ? $info[$obj_type][$bundle]: array();
}

/**
 * Retrieve the user-defined weight for a 'pseudo-field' component.
 *
 * @param $obj_type
 *   The type of $object; e.g. 'node' or 'user'.
 * @param $bundle
 *   The bundle name.
 * @param $pseudo_field
 *   The name of the 'pseudo-field'.
 * @return
 *   The weight for the 'pseudo-field', respecting the user settings stored by
 *   field.module.
 */
function field_extra_field_weight($obj_type, $bundle, $pseudo_field) {
  $extra = field_extra_fields($obj_type, $bundle);
  if (isset($extra[$pseudo_field])) {
    return $extra[$pseudo_field]['weight'];
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
  }
}

/**
 * Pre-render callback to adjust weights of non-field elements on objects.
 */
function _field_extra_weights_pre_render($elements) {
  if (isset($elements['#extra_fields'])) {
    foreach ($elements['#extra_fields'] as $key => $value) {
      // Some core 'fields' use a different key in node forms and in 'view'
      // render arrays. Ensure that we are not on a form first.
      if (!isset($elements['#build_id']) && isset($value['view']) && isset($elements[$value['view']])) {
        $elements[$value['view']]['#weight'] = $value['weight'];
      }
      elseif (isset($elements[$key])) {
        $elements[$key]['#weight'] = $value['weight'];
      }
    }
  }
  return $elements;
}

443
/**
444
 * Clear the field info and field data caches.
445
 */
446
function field_cache_clear() {
447
  cache_clear_all('*', 'cache_field', TRUE);
448
  field_info_cache_clear();
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
}

/**
 * Like filter_xss_admin(), but with a shorter list of allowed tags.
 *
 * Used for items entered by administrators, like field descriptions,
 * allowed values, where some (mainly inline) mark-up may be desired
 * (so check_plain() is not acceptable).
 */
function field_filter_xss($string) {
  return filter_xss($string, _field_filter_xss_allowed_tags());
}

/**
 * List of tags allowed by field_filter_xss().
 */
function _field_filter_xss_allowed_tags() {
  return array('a', 'b', 'big',  'code', 'del', 'em', 'i', 'ins',  'pre', 'q', 'small', 'span', 'strong', 'sub', 'sup', 'tt', 'ol', 'ul', 'li', 'p', 'br', 'img');
}

/**
 * Human-readable list of allowed tags, for display in help texts.
 */
function _field_filter_xss_display_allowed_tags() {
  return '<' . implode('> <', _field_filter_xss_allowed_tags()) . '>';
}

/**
 * Format a field item for display.
 *
 * TODO D7 : do we still need field_format ?
 * - backwards compatibility of templates - check what fallbacks we can propose...
481
 * - was used by Views integration in CCK in D6 - do we need now?
482
483
484
485
 * At least needs a little rehaul/update...
 *
 * Used to display a field's values outside the context of the $node, as
 * when fields are displayed in Views, or to display a field in a template
486
 * using a different formatter than the one set up on the 'Manage display' tab
487
488
489
490
491
492
493
 * for the node's context.
 *
 * @param $field
 *   Either a field array or the name of the field.
 * @param $item
 *   The field item(s) to be formatted (such as $node->field_foo[0],
 *   or $node->field_foo if the formatter handles multiple values itself)
494
495
 * @param $formatter_type
 *   The name of the formatter type to use.
496
497
498
499
500
501
502
503
504
 * @param $node
 *   Optionally, the containing node object for context purposes and
 *   field-instance options.
 *
 * @return
 *   A string containing the contents of the field item(s) sanitized for display.
 *   It will have been passed through the necessary check_plain() or check_markup()
 *   functions as necessary.
 */
505
function field_format($obj_type, $object, $field, $item, $formatter_type = NULL, $formatter_settings = array()) {
506
507
508
509
  if (!is_array($field)) {
    $field = field_info_field($field);
  }

510
  if (field_access('view', $field, $obj_type, $object)) {
511
512
513
    $field_type = field_info_field_types($field['type']);

    // We need $field, $instance, $obj_type, $object to be able to display a value...
514
    list(, , $bundle) = entity_extract_ids($obj_type, $object);
515
    $instance = field_info_instance($obj_type, $field['field_name'], $bundle);
516
517

    $display = array(
518
      'type' => $formatter_type ? $formatter_type : $field_type['default_formatter'],
519
520
      'settings' => $formatter_settings,
    );
521
522
523
    $display['settings'] += field_info_formatter_settings($display['type']);

    if ($display['type'] !== 'hidden') {
524
525
526
527
528
      $theme = $formatter['module'] . '_formatter_' . $display['type'];

      $element = array(
        '#theme' => $theme,
        '#field_name' => $field['field_name'],
529
        '#object_type' => $obj_type,
530
531
532
533
        '#bundle' => $bundle,
        '#formatter' => $display['type'],
        '#settings' => $display['settings'],
        '#object' => $object,
534
        '#object_type' => $obj_type,
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
        '#delta' => isset($item['#delta']) ? $item['#delta'] : NULL,
      );

      if (field_behaviors_formatter('multiple values', $display) == FIELD_BEHAVIOR_DEFAULT) {
        // Single value formatter.

        // hook_field('sanitize') expects an array of items, so we build one.
        $items = array($item);
        $function = $field['module'] . '_field_sanitize';
        if (function_exists($function)) {
          $function($obj_type, $object, $field, $instance, $items);
        }

        $element['#item'] = $items[0];
      }
      else {
        // Multiple values formatter.
        $items = $item;
        $function = $field['module'] . '_field_sanitize';
        if (function_exists($function)) {
          $function($obj_type, $object, $field, $instance, $items);
        }

        foreach ($items as $delta => $item) {
          $element[$delta] = array(
            '#item' => $item,
            '#weight' => $delta,
          );
        }
      }

      return theme($theme, $element);
    }
  }
}

/**
572
 * Returns a renderable array for the value of a single field in an object.
573
 *
574
 * The resulting output is a fully themed field with label and multiple values.
575
 *
576
577
578
579
580
581
 * This function can be used by third-party modules that need to output an
 * isolated field.
 * - Do not use inside node (or other entities) templates, use
 *   render($content[FIELD_NAME]) instead.
 * - Do not use to display all fields in an object, use
 *   field_attach_prepare_view() and field_attach_view() instead.
582
 *
583
584
585
586
587
 * The function takes care of invoking the prepare_view steps. It also respects
 * field access permissions.
 *
 * @param $obj_type
 *   The type of $object; e.g. 'node' or 'user'.
588
 * @param $object
589
590
591
592
593
594
 *   The object containing the field to display. Must at least contain the id
 *   key and the field data to display.
 * @param $field_name
 *   The name of the field to display.
 * @param $display
 *   Can be either:
595
596
 *   - The name of a view mode. The field will be displayed according to the
 *     display settings specified for this view mode in the $instance
597
 *     definition for the field in the object's bundle.
598
599
 *     If no display settings are found for the view mode, the settings for
 *     the 'full' view mode will be used.
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
 *   - An array of display settings, as found in the 'display' entry of
 *     $instance definitions. The following kay/value pairs are allowed:
 *     - label: (string) Position of the label. The default 'field' theme
 *       implementation supports the values 'inline', 'above' and 'hidden'.
 *       Defaults to 'above'.
 *     - type: (string) The formatter to use. Defaults to the
 *       'default_formatter' for the field type, specified in
 *       hook_field_info(). The default formatter will also be used if the
 *       requested formatter is not available.
 *     - settings: (array) Settings specific to the formatter. Defaults to the
 *       formatter's default settings, specified in
 *       hook_field_formatter_info().
 *     - weight: (float) The weight to assign to the renderable element.
 *       Defaults to 0.
 * @param $langcode
 *   (Optional) The language the field values are to be shown in. The site's
 *   current language fallback logic will be applied no values are available
 *   for the language. If no language is provided the current language will be
 *   used.
619
 * @return
620
 *   A renderable array for the field value.
621
 */
622
623
function field_view_field($obj_type, $object, $field_name, $display = array(), $langcode = NULL) {
  $output = array();
624

625
626
627
628
629
630
  if ($field = field_info_field($field_name)) {
    if (is_array($display)) {
      // When using custom display settings, fill in default values.
      $display = _field_info_prepare_instance_display($field, $display);
    }
    else {
631
632
      // When using a view mode, make sure we have settings for it, or fall
      // back to the 'full' view mode.
633
634
635
636
637
      list(, , $bundle) = entity_extract_ids($obj_type, $object);
      $instance = field_info_instance($obj_type, $field_name, $bundle);
      if (!isset($instance['display'][$display])) {
        $display = 'full';
      }
638
639
    }

640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
    // Hook invocations are done through the _field_invoke() functions in
    // 'single field' mode, to reuse the language fallback logic.
    $options = array('field_name' => $field_name, 'language' => field_multilingual_valid_language($langcode, FALSE));
    $null = NULL;
    list($id) = entity_extract_ids($obj_type, $object);

    // First let the field types do their preparation.
    _field_invoke_multiple('prepare_view', $obj_type, array($id => $object), $display, $null, $options);
    // Then let the formatters do their own specific massaging.
    _field_invoke_multiple_default('prepare_view', $obj_type, array($id => $object), $display, $null, $options);
    // Build the renderable array.
    $result = _field_invoke_default('view', $obj_type, $object, $display, $null, $options);

    // Invoke hook_field_attach_view_alter() to tet other modules alter the
    // renderable array, as in a full field_attach_view() execution.
    $context = array(
      'obj_type' => $obj_type,
      'object' => $object,
658
      'view_mode' => '_custom',
659
660
661
      'langcode' => $langcode,
    );
    drupal_alter('field_attach_view', $result, $context);
662

663
664
665
666
    if (isset($result[$field_name])) {
      $output = $result[$field_name];
      $output['#attached']['css'][] = drupal_get_path('module', 'field') . '/theme/field.css';
    }
667
  }
668

669
670
671
  return $output;
}

672
673
674
675
676
677
678
679
680
/**
 * Determine whether a field has any data.
 *
 * @param $field
 *   A field structure.
 * @return
 *   TRUE if the field has data for any object; FALSE otherwise.
 */
function field_has_data($field) {
681
  $results = field_attach_query($field['id'], array(), array('limit' => 1));
682
683
684
  return !empty($results);
}

685
686
687
688
689
690
691
692
693
/**
 * Determine whether the user has access to a given field.
 *
 * @param $op
 *   The operation to be performed. Possible values:
 *   - "edit"
 *   - "view"
 * @param $field
 *   The field on which the operation is to be performed.
694
695
696
697
 * @param $obj_type
 *   The type of $object; e.g. 'node' or 'user'.
 * @param $object
 *   (optional) The object for the operation.
698
699
700
701
702
703
 * @param $account
 *   (optional) The account to check, if not given use currently logged in user.
 * @return
 *   TRUE if the operation is allowed;
 *   FALSE if the operation is denied.
 */
704
function field_access($op, $field, $obj_type, $object = NULL, $account = NULL) {
705
706
  global $user;

707
  if (!isset($account)) {
708
709
710
    $account = $user;
  }

711
712
713
714
  foreach (module_implements('field_access') as $module) {
    $function = $module . '_field_access';
    $access = $function($op, $field, $obj_type, $object, $account);
    if ($access === FALSE) {
715
716
717
718
719
720
      return FALSE;
    }
  }
  return TRUE;
}

721
/**
722
 * Helper function to extract the bundle name of from a bundle object.
723
724
725
726
727
728
729
730
731
732
733
734
735
736
 *
 * @param $obj_type
 *   The type of $object; e.g. 'node' or 'user'.
 * @param $bundle
 *   The bundle object (or string if bundles for this object type do not exist
 *   as standalone objects).
 * @return
 *   The bundle name.
 */
function field_extract_bundle($obj_type, $bundle) {
  if (is_string($bundle)) {
    return $bundle;
  }

737
  $info = entity_get_info($obj_type);
738
739
740
741
742
  if (is_object($bundle) && isset($info['bundle keys']['bundle']) && isset($bundle->{$info['bundle keys']['bundle']})) {
    return $bundle->{$info['bundle keys']['bundle']};
  }
}

743
744
745
746
747
748
749
750
/**
 * Theme preprocess function for field.tpl.php.
 *
 * @see field.tpl.php
 */
function template_preprocess_field(&$variables) {
  $element = $variables['element'];

751
752
  // @todo Convert to using drupal_html_class() after benchmarking the impact of
  //   doing so.
753
754
  $field_type_css = strtr($element['#field_type'], '_', '-');
  $field_name_css = strtr($element['#field_name'], '_', '-');
755

756
  // Prepare an $items variable that the template can simply loop on.
757
758
759
  // Filter out non-children properties that might have been added if the
  // renderable array has gone through form_builder().
  $items = array_intersect_key($element, array_flip(element_children($element)));
760
761

  $additions = array(
762
    'object' => $element['#object'],
763
    'view_mode' => $element['#view_mode'],
764
    'items' => $items,
765
766
    'field_type' => $element['#field_type'],
    'field_name' => $element['#field_name'],
767
768
    'field_type_css' => $field_type_css,
    'field_name_css' => $field_name_css,
769
    'label' => check_plain($element['#title']),
770
    'label_display' => $element['#label_display'],
771
    'label_hidden' => $element['#label_display'] == 'hidden',
772
    'field_language' => $element['#language'],
773
    'field_translatable' => $element['#field_translatable'],
774
    'classes_array' => array(
775
      'field',
776
777
778
779
      'field-name-' . $field_name_css,
      'field-type-' . $field_type_css,
      'field-label-' . $element['#label_display'],
    ),
780
781
782
    'template_files' => array(
      'field',
      'field-' . $element['#field_name'],
783
784
      'field-' . $element['#bundle'],
      'field-' . $element['#field_name'] . '-' . $element['#bundle'],
785
786
787
    ),
  );
  $variables = array_merge($variables, $additions);
788
789

  // Initialize attributes for each item.
790
  $variables['item_attributes_array'] = array();
791
792
793
  foreach ($variables['items'] as $delta => $item) {
    $variables['item_attributes_array'][$delta] = array();
  }
794
795
}

796
797
798
799
800
801
802
803
804
805
806
/**
 * Theme process function for field.tpl.php.
 *
 * @see field.tpl.php
 */
function template_process_field(&$variables) {
  // Flatten out attributes for each item.
  foreach ($variables['items'] as $delta => $item) {
    $variables['item_attributes'][$delta] = drupal_attributes($variables['item_attributes_array'][$delta]);
  }
}
807
808
/**
 * @} End of "defgroup field"
809
 */