content.module in Content Construction Kit (CCK) 6

Allows administrators to associate custom fields to content types.

File

content.module

<?php

/**
 * @file
 * Allows administrators to associate custom fields to content types.
 */
define('CONTENT_DB_STORAGE_PER_FIELD', 0);
define('CONTENT_DB_STORAGE_PER_CONTENT_TYPE', 1);
define('CONTENT_CONTEXTS_SIMPLE', 0);
define('CONTENT_CONTEXTS_ADVANCED', 1);
define('CONTENT_CONTEXTS_ALL', 2);
define('CONTENT_CALLBACK_NONE', 0x1);
define('CONTENT_CALLBACK_DEFAULT', 0x2);
define('CONTENT_CALLBACK_CUSTOM', 0x4);
define('CONTENT_HANDLE_CORE', 0x1);
define('CONTENT_HANDLE_MODULE', 0x2);
function content_help($path, $arg) {
  switch ($path) {
    case 'admin/help#content':
      $output = '<p>' . t('The content module, a required component of the Content Construction Kit (CCK), allows administrators to associate custom fields with content types. In Drupal, content types are used to define the characteristics of a post, including the title and description of the fields displayed on its add and edit pages. Using the content module (and the other helper modules included in CCK), custom fields beyond the default "Title" and "Body" may be added. CCK features are accessible through tabs on the <a href="@content-types">content types administration page</a>. (See the <a href="@node-help">node module help page</a> for more information about content types.)', array(
        '@content-types' => url('admin/content/types'),
        '@node-help' => url('admin/help/node'),
      )) . '</p>';
      $output .= '<p>' . t('When adding a custom field to a content type, you determine its type (whether it will contain text, numbers, or references to other objects) and how it will be displayed (either as a text field or area, a select box, checkbox, radio button, or autocompleting field). A field may have multiple values (i.e., a "person" may have multiple e-mail addresses) or a single value (i.e., an "employee" has a single employee identification number). As you add and edit fields, CCK automatically adjusts the structure of the database as necessary. CCK also provides a number of other features, including intelligent caching for your custom data, an import and export facility for content type definitions, and integration with other contributed modules.') . '</p>';
      $output .= '<p>' . t('Custom field types are provided by a set of optional modules included with CCK (each module provides a different type). The <a href="@modules">modules page</a> allows you to enable or disable CCK components. A default installation of CCK includes:', array(
        '@modules' => url('admin/build/modules'),
      )) . '</p>';
      $output .= '<ul>';
      $output .= '<li>' . t('<em>number</em>, which adds numeric field types, in integer, decimal or floating point form. You may define a set of allowed inputs, or specify an allowable range of values. A variety of common formats for displaying numeric data are available.') . '</li>';
      $output .= '<li>' . t("<em>text</em>, which adds text field types. A text field may contain plain text only, or optionally, may use Drupal's input format filters to securely manage rich text input. Text input fields may be either a single line (text field), multiple lines (text area), or for greater input control, a select box, checkbox, or radio buttons. If desired, CCK can validate the input to a set of allowed values.") . '</li>';
      $output .= '<li>' . t('<em>nodereference</em>, which creates custom references between Drupal nodes. By adding a <em>nodereference</em> field and two different content types, for instance, you can easily create complex parent/child relationships between data (multiple "employee" nodes may contain a <em>nodereference</em> field linking to an "employer" node).') . '</li>';
      $output .= '<li>' . t('<em>userreference</em>, which creates custom references to your sites\' user accounts. By adding a <em>userreference</em> field, you can create complex relationships between your site\'s users and posts. To track user involvement in a post beyond Drupal\'s standard <em>Authored by</em> field, for instance, add a <em>userreference</em> field named "Edited by" to a content type to store a link to an editor\'s user account page.') . '</li>';
      $output .= '<li>' . t('<em>fieldgroup</em>, which creates collapsible fieldsets to hold a group of related fields. A fieldset may either be open or closed by default. The order of your fieldsets, and the order of fields within a fieldset, is managed via a drag-and-drop interface provided by content module.') . '</li>';
      $output .= '</ul>';
      $output .= '<p>' . t('For more information, see the online handbook entry for <a href="@handbook-cck">CCK</a> or the <a href="@project-cck">CCK project page</a>.', array(
        '@handbook-cck' => 'http://drupal.org/handbook/modules/cck',
        '@project-cck' => 'http://drupal.org/project/cck',
      )) . '</p>';
      return $output;
  }
  if (preg_match('!^admin/content/node-type/.*/display!', $path)) {
    if (preg_match('!^admin/content/node-type/.*/display$!', $path)) {
      return t("Configure how this content type's fields and field labels should be displayed when it's viewed in teaser and full-page mode.");
    }
    else {
      return t("Configure how this content type's fields should be displayed when it's rendered in the following contexts.");
    }
  }
  if (preg_match('!^admin/content/node-type/.*/fields$!', $path)) {
    return t('Control the order of fields in the input form.');
  }
}

/**
 * Implementation of hook_devel_caches.
 * Include {cache_content} in the list of tables cleared by devel's 'empty cache'
 */
function content_devel_caches() {
  return array(
    content_cache_tablename(),
  );
}

/**
 * Implementation of hook_flush_caches.
 */
function content_flush_caches() {
  return array(
    content_cache_tablename(),
  );
}

/**
 * Implementation of hook_init().
 */
function content_init() {
  drupal_add_css(drupal_get_path('module', 'content') . '/theme/content.css');
  if (module_exists('views')) {
    module_load_include('inc', 'content', 'includes/content.views');
  }
  if (module_exists('token') && !function_exists('content_token_values')) {
    module_load_include('inc', 'content', 'includes/content.token');
  }
  if (module_exists('diff') && !function_exists('content_diff')) {
    module_load_include('inc', 'content', 'includes/content.diff');
  }
  if (content_menu_needs_rebuild()) {
    content_clear_type_cache(TRUE);
    menu_rebuild();
    content_menu_needs_rebuild(FALSE);
  }
}

/**
 * Flag / unflag the menus for rebuilding, or read the current
 * value of the flag.
 *
 * When adding new content types and fields, a menu rebuild is needed
 * to update field paths, but sometimes it won't work right until
 * other processes complete.
 * We therefore store a flag in the session and actually rebuild on next
 * page load (content_init()).
 */
function content_menu_needs_rebuild($rebuild = NULL) {
  if (!isset($rebuild)) {
    return isset($_SESSION['content_menu_needs_rebuild']);
  }
  elseif ($rebuild) {
    $_SESSION['content_menu_needs_rebuild'] = TRUE;
  }
  else {
    unset($_SESSION['content_menu_needs_rebuild']);
  }
}

/**
 * Implementation of hook_menu().
 */
function content_menu() {
  $items = array();
  $items['admin/content/types/fields'] = array(
    'title' => 'Fields',
    'page callback' => '_content_admin_type_fields',
    'access arguments' => array(
      'administer content types',
    ),
    'file' => 'includes/content.admin.inc',
    'type' => MENU_LOCAL_TASK,
  );

  // Callback for AHAH add more buttons.
  $items['content/js_add_more'] = array(
    'page callback' => 'content_add_more_js',
    // TODO : access rule ?
    'access arguments' => array(
      'access content',
    ),
    'file' => 'includes/content.node_form.inc',
    'type' => MENU_CALLBACK,
  );

  // Make sure this doesn't fire until content_types is working,
  // needed to avoid errors on initial installation.
  if (!defined('MAINTENANCE_MODE')) {
    foreach (node_get_types() as $type) {
      $type_name = $type->type;
      $content_type = content_types($type_name);
      $type_url_str = $content_type['url_str'];
      $items['admin/content/node-type/' . $type_url_str . '/fields'] = array(
        'title' => 'Manage fields',
        'page callback' => 'drupal_get_form',
        'page arguments' => array(
          'content_admin_field_overview_form',
          $type_name,
        ),
        'access arguments' => array(
          'administer content types',
        ),
        'file' => 'includes/content.admin.inc',
        'type' => MENU_LOCAL_TASK,
        'weight' => 1,
      );
      $items['admin/content/node-type/' . $type_url_str . '/display'] = array(
        'title' => 'Display fields',
        'page callback' => 'drupal_get_form',
        'page arguments' => array(
          'content_admin_display_overview_form',
          $type_name,
        ),
        'access arguments' => array(
          'administer content types',
        ),
        'file' => 'includes/content.admin.inc',
        'type' => MENU_LOCAL_TASK,
        'weight' => 2,
      );
      $items['admin/content/node-type/' . $type_url_str . '/display/general'] = array(
        'title' => 'General',
        'page arguments' => array(
          'content_admin_display_overview_form',
          $type_name,
        ),
        'type' => MENU_DEFAULT_LOCAL_TASK,
        'weight' => 0,
      );
      $items['admin/content/node-type/' . $type_url_str . '/display/advanced'] = array(
        'title' => 'Advanced',
        'page arguments' => array(
          'content_admin_display_overview_form',
          $type_name,
          (string) CONTENT_CONTEXTS_ADVANCED,
        ),
        'access arguments' => array(
          'administer content types',
        ),
        'type' => MENU_LOCAL_TASK,
        'weight' => 1,
      );
      $items['admin/content/node-type/' . $type_url_str . '/add_field'] = array(
        'title' => 'Add field',
        'page callback' => '_content_admin_field_add',
        'page arguments' => array(
          $type_name,
        ),
        'access arguments' => array(
          'administer content types',
        ),
        'file' => 'includes/content.admin.inc',
        'type' => MENU_LOCAL_TASK,
        'weight' => 3,
      );
      foreach ($content_type['fields'] as $field) {
        $field_name = $field['field_name'];
        $items['admin/content/node-type/' . $type_url_str . '/fields/' . $field_name] = array(
          'title' => $field['widget']['label'],
          'page callback' => 'drupal_get_form',
          'page arguments' => array(
            '_content_admin_field',
            $type_name,
            $field_name,
          ),
          'access arguments' => array(
            'administer content types',
          ),
          'file' => 'includes/content.admin.inc',
          'type' => MENU_LOCAL_TASK,
        );
        $items['admin/content/node-type/' . $type_url_str . '/fields/' . $field_name . '/remove'] = array(
          'title' => 'Remove field',
          'page callback' => 'drupal_get_form',
          'page arguments' => array(
            '_content_admin_field_remove',
            $type_name,
            $field_name,
          ),
          'access arguments' => array(
            'administer content types',
          ),
          'file' => 'includes/content.admin.inc',
          'type' => MENU_CALLBACK,
        );
      }
    }
  }
  return $items;
}

/**
 * Implementation of hook_theme().
 */
function content_theme() {
  $path = drupal_get_path('module', 'content') . '/theme';
  return array(
    'content_field_view' => array(
      'template' => 'field',
      'arguments' => array(
        'element' => NULL,
      ),
      'path' => $path,
    ),
    'content_admin_field_overview_form' => array(
      'arguments' => array(
        'form' => NULL,
      ),
    ),
    'content_admin_display_overview_form' => array(
      'arguments' => array(
        'form' => NULL,
      ),
    ),
    'content_admin_field_add_new_field_widget_type' => array(
      'arguments' => array(
        'form' => NULL,
      ),
    ),
    'content_view_multiple_field' => array(
      'arguments' => array(
        'items' => NULL,
        'field' => NULL,
        'data' => NULL,
      ),
    ),
    'content_multiple_values' => array(
      'arguments' => array(
        'element' => NULL,
      ),
    ),
  );
}

/**
 * Load data for a node type's fields.
 *
 * When loading one of the content.module nodes, we need to let each field handle
 * its own loading. This can make for a number of queries in some cases, so we
 * cache the loaded object structure and invalidate it during the update process.
 */
function content_load($node) {
  $cid = 'content:' . $node->nid . ':' . $node->vid;
  if ($cached = cache_get($cid, content_cache_tablename())) {
    return $cached->data;
  }
  else {
    $default_additions = _content_field_invoke_default('load', $node);
    if ($default_additions) {
      foreach ($default_additions as $key => $value) {
        $node->{$key} = $value;
      }
    }
    $additions = _content_field_invoke('load', $node);
    if ($additions) {
      foreach ($additions as $key => $value) {
        $node->{$key} = $value;
        $default_additions[$key] = $value;
      }
    }
    cache_set($cid, $default_additions, content_cache_tablename());
    return $default_additions;
  }
}

/**
 * Nodeapi 'validate' op.
 *
 */
function content_validate(&$node) {
  _content_field_invoke('validate', $node);
  _content_field_invoke_default('validate', $node);
}

/**
 * Nodeapi 'presave' op.
 *
 */
function content_presave(&$node) {
  _content_field_invoke('presave', $node);
  _content_field_invoke_default('presave', $node);
}

/**
 * Nodeapi 'insert' op.
 *
 * Insert node type fields.
 */
function content_insert(&$node) {
  _content_field_invoke('insert', $node);
  _content_field_invoke_default('insert', $node);
}

/**
 * Nodeapi 'update' op.
 *
 * Update node type fields.
 */
function content_update(&$node) {
  _content_field_invoke('update', $node);
  _content_field_invoke_default('update', $node);
  cache_clear_all('content:' . $node->nid . ':' . $node->vid, content_cache_tablename());
}

/**
 * Nodeapi 'delete' op.
 *
 * Delete node type fields.
 */
function content_delete(&$node) {
  $type = content_types($node->type);
  if (!empty($type['fields'])) {
    _content_field_invoke('delete', $node);
    _content_field_invoke_default('delete', $node);
  }
  $table = _content_tablename($type['type'], CONTENT_DB_STORAGE_PER_CONTENT_TYPE);
  if (db_table_exists($table)) {
    db_query('DELETE FROM {' . $table . '} WHERE nid = %d', $node->nid);
  }
  cache_clear_all('content:' . $node->nid, content_cache_tablename(), TRUE);
}

/**
 * Nodeapi 'delete_revision' op.
 *
 * Delete node type fields for a revision.
 */
function content_delete_revision(&$node) {
  $type = content_types($node->type);
  if (!empty($type['fields'])) {
    _content_field_invoke('delete revision', $node);
    _content_field_invoke_default('delete revision', $node);
  }
  $table = _content_tablename($type['type'], CONTENT_DB_STORAGE_PER_CONTENT_TYPE);
  if (db_table_exists($table)) {
    db_query('DELETE FROM {' . $table . '} WHERE vid = %d', $node->vid);
  }
  cache_clear_all('content:' . $node->nid . ':' . $node->vid, content_cache_tablename());
}

/**
 * Nodeapi 'view' op.
 *
 * Generate field render arrays.
 */
function content_view(&$node, $teaser = FALSE, $page = FALSE) {

  // Let field modules sanitize their data for output.
  _content_field_invoke('sanitize', $node, $teaser, $page);

  // Merge fields.
  $additions = _content_field_invoke_default('view', $node, $teaser, $page);
  $node->content = array_merge((array) $node->content, $additions);

  // Adjust weights for non-CCK fields.
  $type = content_types($node->type);
  foreach ($type['extra'] as $key => $value) {

    // Some core 'fields' use a different key in node forms and in 'view'
    // render arrays.
    if (isset($value['view']) && isset($node->content[$value['view']])) {
      $node->content[$value['view']]['#weight'] = $value['weight'];
    }
    elseif (isset($node->content[$key])) {
      $node->content[$key]['#weight'] = $value['weight'];
    }
  }
}

/**
 * Nodeapi 'alter' op.
 *
 * Add back the formatted values in the 'view' element for all fields,
 * so that node templates can use it.
 */
function content_alter(&$node, $teaser = FALSE, $page = FALSE) {
  _content_field_invoke_default('alter', $node, $teaser, $page);
}

/**
 * Nodeapi 'prepare translation' op.
 *
 * Generate field render arrays.
 */
function content_prepare_translation(&$node) {
  $additions = _content_field_invoke_default('prepare translation', $node);
  $node = (object) array_merge((array) $node, $additions);
}

/**
 * Implementation of hook_nodeapi().
 */
function content_nodeapi(&$node, $op, $teaser, $page) {
  switch ($op) {
    case 'load':
      return content_load($node);
    case 'validate':
      content_validate($node);
      break;
    case 'presave':
      content_presave($node);
      break;
    case 'insert':
      content_insert($node);
      break;
    case 'update':
      content_update($node);
      break;
    case 'delete':
      content_delete($node);
      break;
    case 'delete revision':
      content_delete_revision($node);
      break;
    case 'view':
      content_view($node, $teaser, $page);
      break;
    case 'alter':
      content_alter($node, $teaser, $page);
      break;
    case 'prepare translation':
      content_prepare_translation($node);
      break;
  }
}

/**
 *  Implementation of hook_form_alter().
 */
function content_form_alter(&$form, $form_state, $form_id) {
  if (isset($form['type']) && isset($form['#node']) && $form['type']['#value'] . '_node_form' == $form_id) {
    module_load_include('inc', 'content', 'includes/content.node_form');

    // Merge field widgets.
    $form = array_merge($form, content_form($form, $form_state));

    // Adjust weights for non-CCK fields.
    $type = content_types($form['type']['#value']);
    foreach ($type['extra'] as $key => $value) {
      if (isset($form[$key])) {
        $form[$key]['#weight'] = $value['weight'];

        // Special case for the 'menu path' fieldset : we keep it
        // just below the title.
        if ($key == 'title' && isset($form['menu'])) {
          $form['menu']['#weight'] = $value['weight'] + 0.1;
        }
      }
    }
  }
}

/**
 * Theme an individual form element.
 *
 * Combine multiple values into a table with drag-n-drop reordering.
 */
function theme_content_multiple_values($element) {
  $field_name = $element['#field_name'];
  $field = content_fields($field_name);
  $output = '';
  if ($field['multiple'] >= 1) {
    $table_id = $element['#field_name'] . '_values';
    $order_class = $element['#field_name'] . '-delta-order';
    $required = !empty($element['#required']) ? '<span class="form-required" title="' . t('This field is required.') . '">*</span>' : '';
    $header = array(
      array(
        'data' => t('!title: !required', array(
          '!title' => filter_xss_admin($element['#title']),
          '!required' => $required,
        )),
        'colspan' => 2,
      ),
      t('Order'),
    );
    $rows = array();
    foreach (element_children($element) as $key) {
      if ($key !== $element['#field_name'] . '_add_more') {
        $element[$key]['_weight']['#attributes']['class'] = $order_class;
        $delta_element = drupal_render($element[$key]['_weight']);
        $cells = array(
          array(
            'data' => '',
            'class' => 'content-multiple-drag',
          ),
          drupal_render($element[$key]),
          array(
            'data' => $delta_element,
            'class' => 'delta-order',
          ),
        );
        $rows[] = array(
          'data' => $cells,
          'class' => 'draggable',
        );
      }
    }
    $output .= theme('table', $header, $rows, array(
      'id' => $table_id,
      'class' => 'content-multiple-table',
    ));
    $output .= $element['#description'] ? '<div class="description">' . $element['#description'] . '</div>' : '';
    $output .= drupal_render($element[$element['#field_name'] . '_add_more']);
    drupal_add_tabledrag($table_id, 'order', 'sibling', $order_class);

    // Change the button title to reflect the behavior when using JavaScript.
    // TODO : this should be made a behavior, so it can be reattached when the
    // form is AHAH-updated
    $field_name_css = str_replace('_', '-', $field_name);
    drupal_add_js('if (Drupal.jsEnabled) { $(document).ready(function() { $("#edit-' . $field_name_css . '-' . $field_name_css . '-add-more").val("' . t('Add another item') . '"); }); }', 'inline');
  }
  else {
    foreach (element_children($element) as $key) {
      $output .= drupal_render($element[$key]);
    }
  }
  return $output;
}

/**
 * Modules notify Content module when uninstalled, disabled, etc.
 *
 * @param string $op
 *   the module operation: uninstall, install, enable, disable
 * @param string $module
 *   the name of the affected module.
 * @TODO
 *   figure out exactly what needs to be done by content module when
 *   field modules are installed, uninstalled, enabled or disabled.
 */
function content_notify($op, $module) {
  switch ($op) {
    case 'install':
      content_clear_type_cache();
      break;
    case 'uninstall':
      module_load_include('inc', 'content', 'includes/content.crud');
      content_module_delete($module);
      content_clear_type_cache(TRUE);
      break;
    case 'enable':
      content_associate_fields($module);
      content_clear_type_cache();
      break;
    case 'disable':
      content_clear_type_cache(TRUE);
      break;
  }
}

/**
 * Allows a module to update the database for fields and columns it controls.
 *
 * @param string $module
 *   The name of the module to update on.
 */
function content_associate_fields($module) {
  $module_fields = module_invoke($module, 'field_info');
  if ($module_fields) {
    foreach ($module_fields as $name => $field_info) {
      watchdog('content', 'Updating field type %type with module %module.', array(
        '%type' => $name,
        '%module' => $module,
      ));
      db_query("UPDATE {" . content_field_tablename() . "} SET module = '%s', active = %d WHERE type = '%s'", $module, 1, $name);
    }
  }
  $module_widgets = module_invoke($module, 'widget_info');
  if ($module_widgets) {
    foreach ($module_widgets as $name => $widget_info) {
      watchdog('content', 'Updating widget type %type with module %module.', array(
        '%type' => $name,
        '%module' => $module,
      ));
      db_query("UPDATE {" . content_instance_tablename() . "} SET widget_module = '%s', widget_active = %d WHERE widget_type = '%s'", $module, 1, $name);
    }
  }

  // This is called from updates and installs, so get the install-safe
  // version of a fields array.
  $fields_set = array();
  module_load_include('install', 'content');
  $types = content_types_install();
  foreach ($types as $type_name => $fields) {
    foreach ($fields as $field) {
      if ($field['module'] == $module && !in_array($field['field_name'], $fields_set)) {
        $columns = module_invoke($field['module'], 'field_settings', 'database columns', $field);
        db_query("UPDATE {" . content_field_tablename() . "} SET db_columns = '%s' WHERE field_name = '%s'", serialize($columns), $field['field_name']);
        $fields_set[] = $field['field_name'];
      }
    }
  }
}

/**
 * Implementation of hook_field(). Handles common field housekeeping.
 *
 * This implementation is special, as content.module does not define any field
 * types. Instead, this function gets called after the type-specific hook, and
 * takes care of default stuff common to all field types.
 *
 * Db-storage ops ('load', 'insert', 'update', 'delete', 'delete revisions')
 * are not executed field by field, and are thus handled separately in
 * content_storage.
 *
 * The 'view' operation constructs the $node in a way that you can use
 * drupal_render() to display the formatted output for an individual field.
 * i.e. print drupal_render($node->field_foo);
 *
 * The code now supports both single value formatters, which theme an
 * individual item value as has been done in previous version of CCK,
 * and multiple value formatters, which theme all values for the field
 * in a single theme. The multiple value formatters could be used, for
 * instance, to plot field values on a single map or display them
 * in a graph. Single value formatters are the default, multiple value
 * formatters can be designated as such in formatter_info().
 *
 * The node array will look like:
 *   $node->content['field_foo'] = array(
 *     '#type' => 'content_field_view',
 *     '#title' => 'label'
 *     '#field_name' => 'field_name',
 *     '#node' => $node,
 *     'items' =>
 *       0 => array(
 *         '#item' => $items[0],
 *         // Only for 'single-value' formatters
 *         '#theme' => $theme,
 *         '#field_name' => 'field_name',
 *         '#type_name' => $node->type,
 *         '#formatter' => $formatter_name,
 *       ),
 *       1 => array(
 *         '#item' => $items[1],
 *         // Only for 'single-value' formatters
 *         '#theme' => $theme,
 *         '#field_name' => 'field_name',
 *         '#type_name' => $node->type,
 *         '#formatter' => $formatter_name,
 *       ),
 *       // Only for 'multiple-value' formatters
 *       '#theme' => $theme,
 *       '#field_name' => 'field_name',
 *       '#type_name' => $node->type,
 *       '#formatter' => $formatter_name,
 *     ),
 *   );
 */
function content_field($op, &$node, $field, &$items, $teaser, $page) {
  switch ($op) {
    case 'validate':

      // TODO : here we could validate that the number of multiple data is correct ?
      // We're controlling the number of fields to fill out and saving empty
      // ones if a specified number is requested, so no reason to do any validation
      // here right now, but if later create a method to indicate whether
      // 'required' means all values must be filled out, we can come back
      // here and check that they're not empty.
      break;
    case 'presave':

      // Manual node_save calls might not have all fields filled in.
      // On node insert, we need to make sure all tables get at least an empty
      // record, or subsequent edits, using drupal_write_record() in update mode,
      // won't insert any data.
      // Missing fields on node update are handled in content_storage().
      if (empty($items) && !isset($node->nid)) {
        foreach (array_keys($field['columns']) as $column) {
          $items[0][$column] = NULL;
        }
        $node->{$field}['field_name'] = $items;
      }

      // If there was an AHAH add more button in this field, don't save it.
      // TODO : is it still needed ?
      unset($items[$field['field_name'] . '_add_more']);

      // If content module is handling multiple values, don't save empty items.
      if (content_handle('widget', 'multiple values', $field) == CONTENT_HANDLE_CORE) {

        // Filter out empty values.
        $items = content_set_empty($field, $items);

        // Reorder items to account for drag-n-drop reordering.
        $items = _content_sort_items($field, $items);
      }
      break;
    case 'view':
      $element = array();
      if ($node->build_mode == NODE_BUILD_NORMAL) {
        $context = $teaser ? 'teaser' : 'full';
      }
      else {
        $context = $node->build_mode;
      }

      // Do not include field labels when indexing content.
      if ($context == NODE_BUILD_SEARCH_INDEX) {
        $field['display_settings']['label']['format'] = 'hidden';
      }
      $field_types = _content_field_types();
      $formatters = $field_types[$field['type']]['formatters'];
      $formatter_name = isset($field['display_settings'][$context]['format']) ? $field['display_settings'][$context]['format'] : 'default';
      if (!isset($formatters[$formatter_name]) && $formatter_name != 'hidden') {

        // This might happen when the selected formatter has been renamed in the
        // module, or if the module has been disabled since then.
        $formatter_name = 'default';
      }
      if (isset($formatters[$formatter_name])) {
        $formatter = $formatters[$formatter_name];
        $theme = $formatter['module'] . '_formatter_' . $formatter_name;
        $single = content_handle('formatter', 'multiple values', $formatter) == CONTENT_HANDLE_CORE;
        $element = array(
          '#type' => 'content_field_view',
          '#title' => $field['widget']['label'],
          '#weight' => $field['widget']['weight'],
          '#field_name' => $field['field_name'],
          '#access' => $formatter_name != 'hidden',
          '#node' => $node,
          '#teaser' => $teaser,
          '#page' => $page,
          '#single' => $single,
          'items' => array(),
        );

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

        // Append formatter information either on each item ('single-value' formatter)
        // or at the upper 'items' level ('multiple-value' formatter)
        $format_info = array(
          '#theme' => $theme,
          '#field_name' => $field['field_name'],
          '#type_name' => $node->type,
          '#formatter' => $formatter_name,
        );
        if ($single) {
          foreach ($items as $delta => $item) {
            $element['items'][$delta] += $format_info;
          }
        }
        else {
          $element['items'] += $format_info;
        }
      }
      return array(
        $field['field_name'] => $element,
      );
    case 'alter':

      // Add back the formatted values in the 'view' element,
      // so that node templates can use it.
      if (isset($node->content[$field['field_name']])) {
        $element = $node->content[$field['field_name']];
        if ($element['#single']) {

          // Single value formatter.
          foreach (element_children($element['items']) as $delta) {

            // Use isset() to avoid undefined index message on #children when field values are empty.
            $items[$delta]['view'] = isset($element['items'][$delta]['#children']) ? $element['items'][$delta]['#children'] : '';
          }
        }
        else {

          // Multiple values formatter.
          $items[0]['view'] = $element['items']['#children'];
        }
      }
      else {
        $items[0]['view'] = '';
      }
      break;
    case 'prepare translation':
      $addition = array();
      if (isset($node->translation_source->{$field}['field_name'])) {
        $addition[$field['field_name']] = $node->translation_source->{$field}['field_name'];
      }
      return $addition;
  }
}

/**
 * Helper function to set NULL values and unset items where needed.
 *
 * If a specified number of multiple values was requested or this is
 * the zero delta, save even if empty and keep a NULL value for each
 * of its columns so there is a marker row in the database, otherwise
 * unset the item.
 *
 * @param array $field
 * @param array $items
 * @return array
 *   returns emptied and adjusted item array
 */
function content_set_empty($field, $items) {
  $function = $field['module'] . '_content_is_empty';
  $max_delta = $field['multiple'] > 1 ? $field['multiple'] : 0;
  foreach ((array) $items as $delta => $item) {
    if ($function($item, $field)) {
      if ($delta <= $max_delta) {
        foreach (array_keys($field['columns']) as $column) {
          $items[$delta][$column] = NULL;
        }
      }
      else {
        unset($items[$delta]);
      }
    }
  }
  return $items;
}

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

/**
 * Sort function for items order.
 * (copied form element_sort(), which acts on #weight keys)
 */
function _content_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;
}

/**
 * TODO : PHPdoc
 */
function content_storage($op, $node) {
  $type_name = $node->type;
  $type = content_types($type_name);
  switch ($op) {
    case 'load':

      // OPTIMIZE : load all non multiple fields in a single JOIN query ?
      // warning : 61-join limit in MySQL ?
      $additions = array();

      // For each table used by this content type,
      foreach ($type['tables'] as $table) {
        $schema = drupal_get_schema($table);
        $query = 'SELECT * FROM {' . $table . '} WHERE vid = %d';

        // If we're loading a table for a multiple field,
        // we fetch all rows (values) ordered by delta,
        // else we only fetch one row.
        $result = isset($schema['fields']['delta']) ? db_query($query . ' ORDER BY delta', $node->vid) : db_query_range($query, $node->vid, 0, 1);

        // For each table row, populate the fields.
        while ($row = db_fetch_array($result)) {

          // For each field stored in the table, add the field item.
          foreach ($schema['content fields'] as $field_name) {
            $item = array();
            $field = content_fields($field_name, $type_name);
            $db_info = content_database_info($field);

            // For each column declared by the field, populate the item.
            foreach ($db_info['columns'] as $column => $attributes) {
              $item[$column] = $row[$attributes['column']];
            }

            // Add the item to the field values for the node.
            if (!isset($additions[$field_name])) {
              $additions[$field_name] = array();
            }
            $additions[$field_name][] = $item;
          }
        }
      }
      return $additions;
    case 'insert':
    case 'update':
      foreach ($type['tables'] as $table) {
        $schema = drupal_get_schema($table);
        $record = array();
        foreach ($schema['content fields'] as $field_name) {
          if (isset($node->{$field_name})) {
            $field = content_fields($field_name, $type_name);

            // Multiple fields need specific handling, we'll deal with them later on.
            if ($field['multiple']) {
              continue;
            }
            $db_info = content_database_info($field);
            foreach ($db_info['columns'] as $column => $attributes) {
              $record[$attributes['column']] = $node->{$field_name}[0][$column];
            }
          }
        }
        if (count($record)) {
          $record['nid'] = $node->nid;
          $record['vid'] = $node->vid;

          // Can't rely on the insert/update op of the node to decide if this
          // is an insert or an update, a node or revision may have existed
          // before any fields were created, so there may not be an entry here.
          // TODO - should we auto create an entry for all existing nodes when
          // fields are added to content types -- either a NULL value
          // or the default value? May need to offer the user an option of
          // how to handle that.
          if (db_result(db_query("SELECT COUNT(*) FROM {" . $table . "} WHERE vid = %d", $node->vid))) {
            content_write_record($table, $record, array(
              'vid',
            ));
          }
          else {
            content_write_record($table, $record);
          }
        }
      }

      // Handle multiple fields.
      foreach ($type['fields'] as $field) {
        if ($field['multiple'] && isset($node->{$field}['field_name'])) {
          $db_info = content_database_info($field);

          // Delete and insert, rather than update, in case a value was added.
          if ($op == 'update') {
            db_query('DELETE FROM {' . $db_info['table'] . '} WHERE vid = %d', $node->vid);
          }
          foreach ($node->{$field}['field_name'] as $delta => $item) {
            $record = array();
            foreach ($db_info['columns'] as $column => $attributes) {
              $record[$attributes['column']] = $item[$column];
            }
            $record['nid'] = $node->nid;
            $record['vid'] = $node->vid;
            $record['delta'] = $delta;
            content_write_record($db_info['table'], $record);
          }
        }
      }
      break;
    case 'delete':
      foreach ($type['tables'] as $table) {
        db_query('DELETE FROM {' . $table . '} WHERE nid = %d', $node->nid);
      }
      break;
    case 'delete revision':
      foreach ($type['tables'] as $table) {
        db_query('DELETE FROM {' . $table . '} WHERE vid = %d', $node->vid);
      }
      break;
  }
}

/**
 * Save a record to the database based upon the schema.
 *
 * Directly copied from core's drupal_write_record, which can't update a
 * column to NULL.
 *
 * Default values are filled in for missing items, and 'serial' (auto increment)
 * types are filled in with IDs.
 *
 * @param $table
 *   The name of the table; this must exist in schema API.
 * @param $object
 *   The object to write. This is a reference, as defaults according to
 *   the schema may be filled in on the object, as well as ID on the serial
 *   type(s). Both array an object types may be passed.
 * @param $update
 *   If this is an update, specify the primary keys' field names. It is the
 *   caller's responsibility to know if a record for this object already
 *   exists in the database. If there is only 1 key, you may pass a simple string.
 * @return
 *   Failure to write a record will return FALSE. Otherwise SAVED_NEW or
 *   SAVED_UPDATED is returned depending on the operation performed. The
 *   $object parameter contains values for any serial fields defined by
 *   the $table. For example, $object->nid will be populated after inserting
 *   a new node.
 */
function content_write_record($table, &$object, $update = array()) {

  // Standardize $update to an array.
  if (is_string($update)) {
    $update = array(
      $update,
    );
  }

  // Convert to an object if needed.
  if (is_array($object)) {
    $object = (object) $object;
    $array = TRUE;
  }
  else {
    $array = FALSE;
  }
  $schema = drupal_get_schema($table);
  if (empty($schema)) {
    return FALSE;
  }
  $fields = $defs = $values = $serials = $placeholders = array();

  // Go through our schema, build SQL, and when inserting, fill in defaults for
  // fields that are not set.
  foreach ($schema['fields'] as $field => $info) {

    // Special case -- skip serial types if we are updating.
    if ($info['type'] == 'serial' && count($update)) {
      continue;
    }

    // For inserts, populate defaults from Schema if not already provided
    if (!isset($object->{$field}) && !count($update) && isset($info['default'])) {
      $object->{$field} = $info['default'];
    }

    // Track serial fields so we can helpfully populate them after the query.
    if ($info['type'] == 'serial') {
      $serials[] = $field;

      // Ignore values for serials when inserting data. Unsupported.
      unset($object->{$field});
    }

    // Build arrays for the fields, placeholders, and values in our query.
    if (isset($object->{$field}) || array_key_exists($field, $object)) {
      $fields[] = $field;
      if (isset($object->{$field})) {
        $placeholders[] = db_type_placeholder($info['type']);
        if (empty($info['serialize'])) {
          $values[] = $object->{$field};
        }
        else {
          $values[] = serialize($object->{$field});
        }
      }
      else {
        $placeholders[] = 'NULL';
      }
    }
  }

  // Build the SQL.
  $query = '';
  if (!count($update)) {
    $query = "INSERT INTO {" . $table . "} (" . implode(', ', $fields) . ') VALUES (' . implode(', ', $placeholders) . ')';
    $return = SAVED_NEW;
  }
  else {
    $query = '';
    foreach ($fields as $id => $field) {
      if ($query) {
        $query .= ', ';
      }
      $query .= $field . ' = ' . $placeholders[$id];
    }
    foreach ($update as $key) {
      $conditions[] = "{$key} = " . db_type_placeholder($schema['fields'][$key]['type']);
      $values[] = $object->{$key};
    }
    $query = "UPDATE {" . $table . "} SET {$query} WHERE " . implode(' AND ', $conditions);
    $return = SAVED_UPDATED;
  }

  // Execute the SQL.
  if (db_query($query, $values)) {
    if ($serials) {

      // Get last insert ids and fill them in.
      foreach ($serials as $field) {
        $object->{$field} = db_last_insert_id($table, $field);
      }
    }

    // If we began with an array, convert back so we don't surprise the caller.
    if ($array) {
      $object = (array) $object;
    }
    return $return;
  }
  return FALSE;
}

/**
 * Invoke a field hook.
 *
 * For each operation, both this function and _content_field_invoke_default() are
 * called so that the default database handling can occur.
 */
function _content_field_invoke($op, &$node, $teaser = NULL, $page = NULL) {
  $type_name = is_string($node) ? $node : (is_array($node) ? $node['type'] : $node->type);
  $type = content_types($type_name);
  $field_types = _content_field_types();
  $return = array();
  foreach ($type['fields'] as $field) {
    $items = isset($node->{$field}['field_name']) ? $node->{$field}['field_name'] : array();

    // Make sure AHAH 'add more' button isn't sent to the fields for processing.
    unset($items[$field['field_name'] . '_add_more']);
    $module = $field_types[$field['type']]['module'];
    $function = $module . '_field';
    if (function_exists($function)) {
      $result = $function($op, $node, $field, $items, $teaser, $page);
      if (is_array($result)) {
        $return = array_merge($return, $result);
      }
      else {
        if (isset($result)) {
          $return[] = $result;
        }
      }
    }

    // test for values in $items in case modules added items on insert
    if (isset($node->{$field}['field_name']) || count($items)) {
      $node->{$field}['field_name'] = $items;
    }
  }
  return $return;
}

/**
 * Invoke content.module's version of a field hook.
 */
function _content_field_invoke_default($op, &$node, $teaser = NULL, $page = NULL) {
  $type_name = is_string($node) ? $node : (is_array($node) ? $node['type'] : $node->type);
  $type = content_types($type_name);
  $field_types = _content_field_types();
  $return = array();

  // The operations involving database queries are better off handled by table
  // rather than by field.
  if (in_array($op, array(
    'load',
    'insert',
    'update',
    'delete',
    'delete revision',
  ))) {
    return content_storage($op, $node);
  }
  else {
    foreach ($type['fields'] as $field) {
      $items = isset($node->{$field}['field_name']) ? $node->{$field}['field_name'] : array();
      $result = content_field($op, $node, $field, $items, $teaser, $page);
      if (is_array($result)) {
        $return = array_merge($return, $result);
      }
      else {
        if (isset($result)) {
          $return[] = $result;
        }
      }
      if (isset($node->{$field}['field_name'])) {
        $node->{$field}['field_name'] = $items;
      }
    }
  }
  return $return;
}

/**
 * Return a list of all content types.
 *
 * @param $content_type_name
 *   If set, return information on just this type.
 */
function content_types($type_name = NULL) {

  // handle type name with either an underscore or a dash
  $type_name = !empty($type_name) ? str_replace('-', '_', $type_name) : NULL;
  $info = _content_type_info();
  if (isset($info['content types'])) {
    if (!isset($type_name)) {
      return $info['content types'];
    }
    if (isset($info['content types'][$type_name])) {
      return $info['content types'][$type_name];
    }
  }
}

/**
 * Return a list of all fields.
 *
 * @param $field_name
 *   If set, return information on just this field.
 * @param $content_type_name
 *   If set, return information of the field within the context of this content
 *   type.
 */
function content_fields($field_name = NULL, $content_type_name = NULL) {
  $info = _content_type_info();
  if (isset($info['fields'])) {
    if (!isset($field_name)) {
      return $info['fields'];
    }
    if (isset($info['fields'][$field_name])) {
      if (!isset($content_type_name)) {
        return $info['fields'][$field_name];
      }
      if (isset($info['content types'][$content_type_name]['fields'][$field_name])) {
        return $info['content types'][$content_type_name]['fields'][$field_name];
      }
    }
  }
}

/**
 * Return a list of field types.
 */
function _content_field_types() {
  $info = _content_type_info();
  return isset($info['field types']) ? $info['field types'] : array();
}

/**
 * Return a list of widget types.
 */
function _content_widget_types() {
  $info = _content_type_info();
  return isset($info['widget types']) ? $info['widget types'] : array();
}

/**
 * Collate all information on content types, fields, and related structures.
 *
 * @param $reset
 *   If TRUE, clear the cache and fetch the information from the database again.
 */
function _content_type_info($reset = FALSE) {
  static $info;
  if ($reset || !isset($info)) {

    // Make sure this function doesn't run until the tables have been created,
    // for instance, when first enabled and called from content_menu().
    if (!db_table_exists(content_field_tablename()) || !db_table_exists(content_instance_tablename())) {
      return array();
    }
    if ($cached = cache_get('content_type_info', content_cache_tablename())) {
      $info = $cached->data;
    }
    else {
      $info = array(
        'field types' => array(),
        'widget types' => array(),
        'fields' => array(),
        'content types' => array(),
      );

      // Populate field types.
      foreach (module_list() as $module) {
        $module_field_types = module_invoke($module, 'field_info');
        if ($module_field_types) {
          foreach ($module_field_types as $name => $field_info) {

            // Truncate names to match the value that is stored in the database.
            $db_name = substr($name, 0, 32);
            $info['field types'][$db_name] = $field_info;
            $info['field types'][$db_name]['module'] = $module;
            $info['field types'][$db_name]['formatters'] = array();
          }
        }
      }

      // Populate widget types and formatters for known field types.
      foreach (module_list() as $module) {
        if ($module_widgets = module_invoke($module, 'widget_info')) {
          foreach ($module_widgets as $name => $widget_info) {

            // Truncate names to match the value that is stored in the database.
            $db_name = substr($name, 0, 32);
            $info['widget types'][$db_name] = $widget_info;
            $info['widget types'][$db_name]['module'] = $module;

            // Replace field types with db_compatible version of known field types.
            $info['widget types'][$db_name]['field types'] = array();
            foreach ($widget_info['field types'] as $field_type) {
              $field_type_db_name = substr($field_type, 0, 32);
              if (isset($info['field types'][$field_type_db_name])) {
                $info['widget types'][$db_name]['field types'][] = $field_type_db_name;
              }
            }
          }
        }
        if ($module_formatters = module_invoke($module, 'field_formatter_info')) {
          foreach ($module_formatters as $name => $formatter_info) {
            foreach ($formatter_info['field types'] as $field_type) {

              // Truncate names to match the value that is stored in the database.
              $db_name = substr($field_type, 0, 32);
              if (isset($info['field types'][$db_name])) {
                $info['field types'][$db_name]['formatters'][$name] = $formatter_info;
                $info['field types'][$db_name]['formatters'][$name]['module'] = $module;
              }
            }
          }
        }
      }

      // Populate actual field instances.
      module_load_include('inc', 'content', 'includes/content.crud');
      foreach (node_get_types() as $type_name => $data) {
        $type = (array) $data;
        $type['url_str'] = str_replace('_', '-', $type['type']);
        $type['fields'] = array();
        $type['tables'] = array();
        $fields = content_field_instance_read(array(
          'type_name' => $type_name,
        ));
        foreach ($fields as $field) {
          $type['fields'][$field['field_name']] = $field;
          $db_info = content_database_info($field);
          $type['tables'][$db_info['table']] = $db_info['table'];
          $info['fields'][$field['field_name']] = $field;
        }

        // Gather information about non-CCK 'fields'.
        $extra = module_invoke_all('content_extra_fields', $type_name);
        drupal_alter('content_extra_fields', $extra, $type_name);

        // Add saved weights.
        foreach (variable_get('content_extra_weights_' . $type_name, array()) as $key => $value) {

          // Some stored entries might not exist anymore, for instance if uploads
          // have been disabled, or vocabularies removed...
          if (isset($extra[$key])) {
            $extra[$key]['weight'] = $value;
          }
        }
        $type['extra'] = $extra;
        $info['content types'][$type_name] = $type;
      }
      cache_set('content_type_info', $info, content_cache_tablename());
    }
  }
  return $info;
}

/**
 *  Implementation of hook_node_type()
 *  React to change in node types
 */
function content_node_type($op, $info) {
  switch ($op) {
    case 'insert':
      module_load_include('inc', 'content', 'includes/content.crud');
      content_type_create($info);
      break;
    case 'update':
      module_load_include('inc', 'content', 'includes/content.crud');
      content_type_update($info);
      break;
    case 'delete':
      module_load_include('inc', 'content', 'includes/content.crud');
      content_type_delete($info);
      break;
  }
}

/**
 * Clear the cache of content_types; called in several places when content
 * information is changed.
 */
function content_clear_type_cache($rebuild_schema = FALSE) {
  cache_clear_all('*', content_cache_tablename(), TRUE);
  _content_type_info(TRUE);

  // Refresh the schema to pick up new information.
  if ($rebuild_schema) {
    $schema = drupal_get_schema(NULL, TRUE);
  }

  //  if (module_exists('views')) {
  //    // Needed because this can be called from .install files
  //    module_load_include('module', 'views');
  //    views_invalidate_cache();
  //  }
}

/**
 * Retrieve the database storage location(s) for a field.
 *
 * TODO : add a word about why it's not included in the global _content_type_info array.
 *
 * @param $field
 *   The field whose database information is requested.
 * @return
 *   An array with the keys:
 *     "table": The name of the database table where the field data is stored.
 *     "columns": An array of columns stored for this field. Each is a collection
 *       of information returned from hook_field_settings('database columns'),
 *       with the addition of a "column" attribute which holds the name of the
 *       database column that stores the data.
 */
function content_database_info($field) {
  $db_info = array();
  if ($field['db_storage'] == CONTENT_DB_STORAGE_PER_FIELD) {
    $db_info['table'] = _content_tablename($field['field_name'], CONTENT_DB_STORAGE_PER_FIELD);
  }
  else {
    $db_info['table'] = _content_tablename($field['type_name'], CONTENT_DB_STORAGE_PER_CONTENT_TYPE);
  }
  $db_info['columns'] = (array) $field['columns'];

  // Generate column names for this field from generic column names.
  foreach ($db_info['columns'] as $column_name => $attributes) {
    $db_info['columns'][$column_name]['column'] = $field['field_name'] . '_' . $column_name;
  }
  return $db_info;
}

/**
 * Helper function for identifying the storage type for a field.
 */
function content_storage_type($field) {
  if ($field['multiple'] > 0) {
    return CONTENT_DB_STORAGE_PER_FIELD;
  }
  else {
    module_load_include('inc', 'content', 'includes/content.crud');
    $instances = content_field_instance_read(array(
      'field_name' => $field['field_name'],
    ));
    if (count($instances) > 1) {
      return CONTENT_DB_STORAGE_PER_FIELD;
    }
  }
  return CONTENT_DB_STORAGE_PER_CONTENT_TYPE;
}

/**
 * Manipulate a 2D array to reverse rows and columns.
 *
 * The default data storage for fields is delta first, column names second.
 * This is sometimes inconvenient for field modules, so this function can be
 * used to present the data in an alternate format.
 *
 * @param $array
 *   The array to be transposed. It must be at least two-dimensional, and
 *   the subarrays must all have the same keys or behavior is undefined.
 * @return
 *   The transposed array.
 */
function content_transpose_array_rows_cols($array) {
  $result = array();
  if (is_array($array)) {
    foreach ($array as $key1 => $value1) {
      if (is_array($value1)) {
        foreach ($value1 as $key2 => $value2) {
          if (!isset($result[$key2])) {
            $result[$key2] = array();
          }
          $result[$key2][$key1] = $value2;
        }
      }
    }
  }
  return $result;
}

/**
 *  Create an array of the allowed values for this field.
 *
 *  Used by number and text fields, expects to find either
 *  PHP code that will return the correct value, or a string
 *  with keys and labels separated with '|' and with each
 *  new value on its own line.
 */
function content_allowed_values($field) {
  static $allowed_values;
  if (isset($allowed_values[$field['field_name']])) {
    return $allowed_values[$field['field_name']];
  }
  $allowed_values[$field['field_name']] = array();
  if (isset($field['allowed_values_php'])) {
    ob_start();
    $result = eval($field['allowed_values_php']);
    if (is_array($result)) {
      $allowed_values[$field['field_name']] = $result;
    }
    ob_end_clean();
  }
  if (empty($allowed_values[$field['field_name']]) && isset($field['allowed_values'])) {
    $list = explode("\n", $field['allowed_values']);
    $list = array_map('trim', $list);
    $list = array_filter($list, 'strlen');
    foreach ($list as $opt) {
      if (strpos($opt, '|') !== FALSE) {
        list($key, $value) = explode('|', $opt);
        $allowed_values[$field['field_name']][$key] = $value ? $value : $key;
      }
      else {
        $allowed_values[$field['field_name']][$opt] = $opt;
      }
    }
  }
  return $allowed_values[$field['field_name']];
}

/**
 * Format a field item for display.
 *
 * 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
 * using a different formatter than the one set up on the Display Fields tab
 * 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)
 * @param $formatter
 *   The name of the formatter to use.
 * @param $node
 *   Optionally, the containing node object for context purposes and
 *   field-instance options.
 *
 * @return
 *   A string containing the contents of the field item(s) sanitized for display.
 *   It will have been passed through the necessary check_plain() or check_markup()
 *   functions as necessary.
 */
function content_format($field, $item, $formatter = 'default', $node = NULL) {
  if (!is_array($field)) {
    $field = content_fields($field);
  }
  $field_types = _content_field_types();
  $formatters = $field_types[$field['type']]['formatters'];
  if (!isset($formatters[$formatter])) {
    $formatter = 'default';
  }
  $formatter_name = $formatter;
  $formatter = $formatters[$formatter_name];
  $theme = $formatter['module'] . '_formatter_' . $formatter_name;
  $element = array(
    '#theme' => $theme,
    '#field_name' => $field['field_name'],
    '#type_name' => isset($node->type) ? $node->type : '',
    '#formatter' => $formatter_name,
  );
  if (content_handle('formatter', 'multiple values', $formatter) == CONTENT_HANDLE_CORE) {

    // Single value formatter.
    // hook_field('sanitize') expects an array of items, so we build one.
    $items = array(
      $item,
    );
    $function = $field['module'] . '_field';
    if (function_exists($function)) {
      $function('sanitize', $node, $field, $items, FALSE, FALSE);
    }
    $element['#item'] = $items[0];
  }
  else {

    // Multiple values formatter.
    $items = $item;
    $function = $field['module'] . '_field';
    if (function_exists($function)) {
      $function('sanitize', $node, $field, $items, FALSE, FALSE);
    }
    foreach ($items as $delta => $item) {
      $element[$delta] = array(
        '#item' => $item,
        '#weight' => $delta,
      );
    }
  }
  return theme($theme, $element);
}

/**
 * Array of possible display contexts for fields.
 */
function _content_admin_display_contexts($selector = CONTENT_CONTEXTS_ALL) {
  $contexts = array();
  if ($selector == CONTENT_CONTEXTS_ALL || $selector == CONTENT_CONTEXTS_SIMPLE) {
    $contexts['teaser'] = t('Teaser');
    $contexts['full'] = t('Full node');
  }
  if ($selector == CONTENT_CONTEXTS_ALL || $selector == CONTENT_CONTEXTS_ADVANCED) {
    $contexts[NODE_BUILD_RSS] = t('RSS Item');
    if (module_exists('search')) {
      $contexts[NODE_BUILD_SEARCH_INDEX] = t('Search Index');
      $contexts[NODE_BUILD_SEARCH_RESULT] = t('Search Result');
    }
  }
  return $contexts;
}

/**
 * Generate a table name for a field or a content type.
 *
 * @param $name
 *   The name of the content type or content field
 * @param $storage
 *   CONTENT_DB_STORAGE_PER_FIELD or CONTENT_DB_STORAGE_PER_CONTENT_TYPE
 * @return
 *   A string containing the generated name for the database table
 */
function _content_tablename($name, $storage, $version = NULL) {
  if (is_null($version)) {
    $version = variable_get('content_schema_version', 0);
  }
  if ($version < 1003) {
    $version = 0;
  }
  else {
    $version = 1003;
  }
  $name = str_replace('-', '_', $name);
  switch ("{$version}-{$storage}") {
    case '0-' . CONTENT_DB_STORAGE_PER_CONTENT_TYPE:
      return "node_{$name}";
    case '0-' . CONTENT_DB_STORAGE_PER_FIELD:
      return "node_data_{$name}";
    case '1003-' . CONTENT_DB_STORAGE_PER_CONTENT_TYPE:
      return "content_type_{$name}";
    case '1003-' . CONTENT_DB_STORAGE_PER_FIELD:
      return "content_{$name}";
  }
}

/**
 * Generate table name for the content field table.
 *
 * Needed because the table name changes depending on version.
 * Using 'content_node_field' instead of 'content_field'
 * to avoid conflicts with field tables that will be prefixed
 * with 'content_field'.
 */
function content_field_tablename($version = NULL) {
  if (is_null($version)) {
    $version = variable_get('content_schema_version', 0);
  }
  return $version < 6001 ? 'node_field' : 'content_node_field';
}

/**
 * Generate table name for the content field instance table.
 *
 * Needed because the table name changes depending on version.
 */
function content_instance_tablename($version = NULL) {
  if (is_null($version)) {
    $version = variable_get('content_schema_version', 0);
  }
  return $version < 6001 ? 'node_field_instance' : 'content_node_field_instance';
}

/**
 * Generate table name for the content cache table.
 *
 * Needed because the table name changes depending on version. Because of
 * a new database column, the content_cache table will be unusable until
 * update 6000 runs, so the cache table will be used instead.
 */
function content_cache_tablename() {
  if (variable_get('content_schema_version', -1) < 6000) {
    return 'cache';
  }
  else {
    return 'cache_content';
  }
}

/**
 * A basic schema used by all field and type tables.
 *
 * This will only add the columns relevant for the specified field.
 * Leave $field['columns'] empty to get only the base schema,
 * otherwise the function will return the whole thing.
 */
function content_table_schema($field = NULL) {
  $schema = array(
    'fields' => array(
      'vid' => array(
        'type' => 'int',
        'unsigned' => TRUE,
        'not null' => TRUE,
        'default' => 0,
      ),
      'nid' => array(
        'type' => 'int',
        'unsigned' => TRUE,
        'not null' => TRUE,
        'default' => 0,
      ),
    ),
    'primary key' => array(
      'vid',
    ),
  );

  // Add delta column if needed.
  if (!empty($field['multiple'])) {
    $schema['fields']['delta'] = array(
      'type' => 'int',
      'unsigned' => TRUE,
      'not null' => TRUE,
      'default' => 0,
    );
    $schema['primary key'][] = 'delta';
  }
  $schema['content fields'] = array();

  // Add field columns column if needed.
  // This function is called from install files where it is not safe
  // to use content_fields() or content_database_info(), so we
  // just used the column values stored in the $field.
  // We also need the schema to include fields from disabled modules
  // or there will be no way to delete those fields.
  if (!empty($field['columns'])) {
    foreach ($field['columns'] as $column => $attributes) {
      $column_name = $field['field_name'] . '_' . $column;
      unset($attributes['column']);
      unset($attributes['sortable']);
      $schema['fields'][$column_name] = $attributes;
    }
    $schema['content fields'][] = $field['field_name'];
  }
  return $schema;
}

/**
 *  Helper function for determining the behavior of a field or a widget
 *  with respect to a given operation. (currently used for field 'view',
 *  and widget 'default values' and 'multiple values')
 *
 *  @param $entity
 *    'field' or 'widget'
 *  @param $op
 *    the name of the operation ('view', 'default value'...)
 *  @param $field
 *    The field array, including widget info.
 *  @return
 *    CONTENT_CALLBACK_NONE    - do nothing for this operation
 *    CONTENT_CALLBACK_CUSTOM  - use the module's callback function.
 *    CONTENT_CALLBACK_DEFAULT - use content module default behavior
 *
 */
function content_callback($entity, $op, $field) {
  switch ($entity) {
    case 'field':
      $info = module_invoke($field['module'], "field_info");
      return isset($info[$field['type']]['callbacks'][$op]) ? $info[$field['type']]['callbacks'][$op] : CONTENT_CALLBACK_DEFAULT;
    case 'widget':
      $info = module_invoke($field['widget']['module'], "widget_info");
      return isset($info[$field['widget']['type']]['callbacks'][$op]) ? $info[$field['widget']['type']]['callbacks'][$op] : CONTENT_CALLBACK_DEFAULT;
  }
}

/**
 *  Helper function for determining the handling of a field, widget or
 *  formatter with respect to a given operation.
 *
 *  Currently used for widgets and formatters 'multiple values'.
 *
 *  @param $entity
 *    'field', 'widget' or 'formatter'
 *  @param $op
 *    the name of the operation ('default values'...)
 *  @param $object
 *    - if $entity is 'field' or 'widget' : the field array,
 *      including widget info.
 *    - if $entity is 'formater' : the formatter array.
 *  @return
 *    CONTENT_HANDLE_CORE    - the content module handles this operation.
 *    CONTENT_HANDLE_MODULE  - the implementing module handles this operation.
 */
function content_handle($entity, $op, $object) {
  switch ($entity) {
    case 'field':
      $info = module_invoke($object['module'], "field_info");
      return isset($info[$object['type']][$op]) ? $info[$object['type']][$op] : CONTENT_HANDLE_CORE;
    case 'widget':
      $info = module_invoke($object['widget']['module'], "widget_info");
      return isset($info[$object['widget']['type']][$op]) ? $info[$object['widget']['type']][$op] : CONTENT_HANDLE_CORE;
    case 'formatter':

      // Much simpler, formatters arrays *are* the 'formatter_info' itself.
      // We let content_handle deal with them only for code consistency.
      return isset($object[$op]) ? $object[$op] : CONTENT_HANDLE_CORE;
  }
}

/**
 *  Helper function to return the correct default value for a field.
 *
 *  @param $node
 *    The node.
 *  @param $field
 *    The field array.
 *  @param $items
 *    The value of the field in the node.
 *  @return
 *    The default value for that field.
 */
function content_default_value(&$form, &$form_state, $field, $delta) {
  $widget_types = _content_widget_types();
  $module = $widget_types[$field['widget']['type']]['module'];
  $default_value = array();
  if (!empty($field['widget']['default_value_php'])) {
    ob_start();
    $result = eval($field['widget']['default_value_php']);
    ob_end_clean();
    if (is_array($result)) {
      $default_value = $result;
    }
  }
  elseif (!empty($field['widget']['default_value'])) {
    $default_value = $field['widget']['default_value'];
  }
  return (array) $default_value;
}

/**
 * Hook elements().
 *
 * Used to add multiple value processing, validation, and themes.
 *
 * FAPI callbacks can be declared here, and the element will be
 * passed to those callbacks.
 *
 * Drupal will automatically theme the element using a theme with
 * the same name as the hook_elements key.
 */
function content_elements() {
  return array(
    'content_multiple_values' => array(),
    'content_field_view' => array(),
  );
}

/**
 * Process variables for field.tpl.php.
 *
 * The $variables array contains the following arguments:
 * - $node
 * - $field
 * - $items
 * - $teaser
 * - $page
 *
 * @see field.tpl.php
 */
function template_preprocess_content_field_view(&$variables) {
  $element = $variables['element'];
  $field = content_fields($element['#field_name'], $element['#node']->type);
  $variables['node'] = $element['#node'];
  $variables['field'] = $field;
  $variables['items'] = array();
  if ($element['#single']) {

    // Single value formatter.
    foreach (element_children($element['items']) as $delta) {
      $variables['items'][$delta] = $element['items'][$delta]['#item'];

      // Use isset() to avoid undefined index message on #children when field values are empty.
      $variables['items'][$delta]['view'] = isset($element['items'][$delta]['#children']) ? $element['items'][$delta]['#children'] : '';
    }
  }
  else {

    // Multiple values formatter.
    // We display the 'all items' output as $items[0], as if it was the
    // output of a single valued field.
    // Raw values are still exposed for all items.
    foreach (element_children($element['items']) as $delta) {
      $variables['items'][$delta] = $element['items'][$delta]['#item'];
    }
    $variables['items'][0]['view'] = $element['items']['#children'];
  }
  $variables['teaser'] = $element['#teaser'];
  $variables['page'] = $element['#page'];
  $field_empty = TRUE;
  foreach ($variables['items'] as $delta => $item) {
    if (!isset($item['view']) || empty($item['view']) && $item['view'] !== 0) {
      $variables['items'][$delta]['empty'] = TRUE;
    }
    else {
      $field_empty = FALSE;
      $variables['items'][$delta]['empty'] = FALSE;
    }
  }
  $additions = array(
    'field_type' => $field['type'],
    'field_name' => $field['field_name'],
    'field_type_css' => strtr($field['type'], '_', '-'),
    'field_name_css' => strtr($field['field_name'], '_', '-'),
    'label' => $field['widget']['label'],
    'label_display' => isset($field['display_settings']['label']['format']) ? $field['display_settings']['label']['format'] : 'above',
    'field_empty' => $field_empty,
  );
  $variables = array_merge($variables, $additions);
}

/**
 * Debugging using hook_content_fieldapi.
 *
 * @TODO remove later
 *
 * @param $op
 * @param $field
 */
function content_content_fieldapi($op, $field) {
  if (module_exists('devel')) {

    //dsm($op);

    //dsm($field);
  }
}

/**
 * Implementation of hook_content_extra_fields.
 *
 * Informations for non-CCK 'node fields' defined in core.
 */
function content_content_extra_fields($type_name) {
  $type = node_get_types('type', $type_name);
  $extra = array();
  if ($type->has_title) {
    $extra['title'] = array(
      'label' => $type->title_label,
      'weight' => -5,
    );
  }
  if ($type->has_body) {
    $extra['body_field'] = array(
      'label' => $type->body_label,
      'weight' => 0,
      'view' => 'body',
    );
  }
  if (module_exists('locale') && variable_get("language_{$type_name}", 0)) {
    $extra['language'] = array(
      'label' => t('Language'),
      'weight' => 0,
    );
  }
  if (module_exists('taxonomy') && taxonomy_get_vocabularies($type_name)) {
    $extra['taxonomy'] = array(
      'label' => t('Taxonomy'),
      'weight' => -3,
    );
  }
  if (module_exists('upload') && variable_get("upload_{$type_name}", TRUE)) {
    $extra['attachments'] = array(
      'label' => t('File attachments'),
      'weight' => 30,
      'view' => 'files',
    );
  }
  return $extra;
}

/**
 * Retrieve the user-defined weight for non-CCK node 'fields'.
 *
 * CCK's 'Manage fields' page lets users reorder node fields, including non-CCK
 * items (body, taxonomy, other hook_nodeapi-added elements by contrib modules...).
 * Contrib modules that want to have their 'fields' supported need to expose
 * them with hook_content_extra_fields, and use this function to retrieve the
 * user-defined weight.
 *
 * @param $type_name
 *   The content type name.
 * @param $pseudo_field_name
 *   The name of the 'field'.
 * @return
 *   The weight for the 'field', respecting the user settings stored
 *   by content.module.
 */
function content_extra_field_weight($type_name, $pseudo_field_name) {
  $type = content_types($type_name);

  // If we don't have the requested item, this may be because the cached
  // information for 'extra' fields hasn't been refreshed yet.
  if (!isset($type['extra'][$pseudo_field_name])) {
    content_clear_type_cache();
  }
  if (isset($type['extra'][$pseudo_field_name])) {
    return $type['extra'][$pseudo_field_name]['weight'];
  }
}

Functions

Name	Description
content_allowed_values	Create an array of the allowed values for this field.
content_alter	Nodeapi 'alter' op.
content_associate_fields	Allows a module to update the database for fields and columns it controls.
content_cache_tablename	Generate table name for the content cache table.
content_callback	Helper function for determining the behavior of a field or a widget with respect to a given operation. (currently used for field 'view', and widget 'default values' and 'multiple values')
content_clear_type_cache	Clear the cache of content_types; called in several places when content information is changed.
content_content_extra_fields	Implementation of hook_content_extra_fields.
content_content_fieldapi	Debugging using hook_content_fieldapi.
content_database_info	Retrieve the database storage location(s) for a field.
content_default_value	Helper function to return the correct default value for a field.
content_delete	Nodeapi 'delete' op.
content_delete_revision	Nodeapi 'delete_revision' op.
content_devel_caches	Implementation of hook_devel_caches. Include {cache_content} in the list of tables cleared by devel's 'empty cache'
content_elements	Hook elements().
content_extra_field_weight	Retrieve the user-defined weight for non-CCK node 'fields'.
content_field	Implementation of hook_field(). Handles common field housekeeping.
content_fields	Return a list of all fields.
content_field_tablename	Generate table name for the content field table.
content_flush_caches	Implementation of hook_flush_caches.
content_format	Format a field item for display.
content_form_alter	Implementation of hook_form_alter().
content_handle	Helper function for determining the handling of a field, widget or formatter with respect to a given operation.
content_help
content_init	Implementation of hook_init().
content_insert	Nodeapi 'insert' op.
content_instance_tablename	Generate table name for the content field instance table.
content_load	Load data for a node type's fields.
content_menu	Implementation of hook_menu().
content_menu_needs_rebuild	Flag / unflag the menus for rebuilding, or read the current value of the flag.
content_nodeapi	Implementation of hook_nodeapi().
content_node_type	Implementation of hook_node_type() React to change in node types
content_notify	Modules notify Content module when uninstalled, disabled, etc.
content_prepare_translation	Nodeapi 'prepare translation' op.
content_presave	Nodeapi 'presave' op.
content_set_empty	Helper function to set NULL values and unset items where needed.
content_storage	TODO : PHPdoc
content_storage_type	Helper function for identifying the storage type for a field.
content_table_schema	A basic schema used by all field and type tables.
content_theme	Implementation of hook_theme().
content_transpose_array_rows_cols	Manipulate a 2D array to reverse rows and columns.
content_types	Return a list of all content types.
content_update	Nodeapi 'update' op.
content_validate	Nodeapi 'validate' op.
content_view	Nodeapi 'view' op.
content_write_record	Save a record to the database based upon the schema.
template_preprocess_content_field_view	Process variables for field.tpl.php.
theme_content_multiple_values	Theme an individual form element.
_content_admin_display_contexts	Array of possible display contexts for fields.
_content_field_invoke	Invoke a field hook.
_content_field_invoke_default	Invoke content.module's version of a field hook.
_content_field_types	Return a list of field types.
_content_sort_items	Helper function to sort items in a field according to user drag-n-drop reordering.
_content_sort_items_helper	Sort function for items order. (copied form element_sort(), which acts on #weight keys)
_content_tablename	Generate a table name for a field or a content type.
_content_type_info	Collate all information on content types, fields, and related structures.
_content_widget_types	Return a list of widget types.

Constants

Name	Description
CONTENT_CALLBACK_CUSTOM
CONTENT_CALLBACK_DEFAULT
CONTENT_CALLBACK_NONE
CONTENT_CONTEXTS_ADVANCED
CONTENT_CONTEXTS_ALL
CONTENT_CONTEXTS_SIMPLE
CONTENT_DB_STORAGE_PER_CONTENT_TYPE
CONTENT_DB_STORAGE_PER_FIELD	@file Allows administrators to associate custom fields to content types.
CONTENT_HANDLE_CORE
CONTENT_HANDLE_MODULE