date.module

<?php

/**
 * @file
 * Defines date/time field types for the Content Construction Kit (CCK).
 */

module_load_include('theme', 'date', 'date');
module_load_include('inc', 'date', '/date.field');
module_load_include('inc', 'date', '/date_elements');

/**
 * Implements hook_menu().
 *
 * Add menu tabs to display pages with details about repeating date values.
 */
function date_menu() {
  $items = array();
  // Repeat dates tab on entity
  if (!module_exists('date_repeat')) {
    return $items;
  }

  $values = date_repeat_bundles();
  foreach ($values as $entity_type => $bundles) {
    if (module_exists('field_collection') && $entity_type == 'field_collection_item') {
      foreach ($bundles as $bundle => $fields) {
        $field = field_info_field($bundle);
        if ($field['type'] == 'field_collection') {
          $path = field_collection_field_get_path($field);
          $count = count(explode('/', $path));
          $items[$path . '/%field_collection_item/repeats'] = array(
           'title' => 'Repeats',
           'page callback' => 'date_repeat_page',
           'page arguments' => array($entity_type, $count),
           'access callback' => 'date_repeat_show',
           'access arguments' => array($entity_type, $count),
           'type' => MENU_LOCAL_TASK,
           'context' => MENU_CONTEXT_PAGE | MENU_CONTEXT_INLINE,
          );
        }
      }
    }
    else {
      $path = $entity_type . '/%' . $entity_type;
      $items[$path . '/repeats'] = array(
       'title' => 'Repeats',
       'page callback' => 'date_repeat_page',
       'page arguments' => array($entity_type, 1),
       'access callback' => 'date_repeat_show',
       'access arguments' => array($entity_type, 1),
       'type' => MENU_LOCAL_TASK,
       'context' => MENU_CONTEXT_PAGE | MENU_CONTEXT_INLINE,
      );
    }
  }
  return $items;
}

/**
 * Implements hook_permission().
 */
function date_permission() {
  return array('view date repeats' => array(
    'title' => t('View Repeating Dates'),
    'description' => t('Allow user to see a page with all the times a date repeats.'),
  ));
}

/**
 * See if the user can access repeat date info for this field.
 */
function date_repeat_show($entity_type = 'node', $entity = NULL) {
  $bundle = date_get_entity_bundle($entity_type, $entity);
  $fields = field_info_instances($entity_type, $bundle);
  foreach ($fields as $field_name => $data) {
    $field = field_info_field($field_name);
    if (in_array($field['type'], array('date', 'datestamp', 'datetime'))) {
      return user_access('view date repeats');
    }
  }
  return FALSE;
}

/**
 * A page to list all values for a repeating date.
 */
function date_repeat_page($entity_type = 'node', $entity = NULL) {
  $bundle = date_get_entity_bundle($entity_type, $entity);
  $info = entity_get_info($entity_type);
  $key = $info['entity keys']['id'];
  drupal_set_title(t('Repeats'));
  $entity->date_repeat_show_all = TRUE;
  $entity->content = array();
  $output = '';
  $fields = field_info_instances($entity_type, $bundle);
  foreach ($fields as $field_name => $data) {
    $field = field_info_field($field_name);
    if (in_array($field['type'], array('date', 'datestamp', 'datetime'))) {
      $field = field_view_field($entity_type, $entity, $field_name, 'full');
      $output .= drupal_render($field);
    }
  }
  return $output;
}

/**
 * Return an array of all entity types and bundles that have repeating date fields.
 */
function date_repeat_bundles() {
  $values = array();
  $items = field_info_instances();
  foreach ($items as $entity_type => $bundles) {
    foreach ($bundles as $bundle => $widgets) {
      foreach ($widgets as $field_name => $widget) {
        $field = field_info_field($field_name);
        if (in_array($field['type'], array('date', 'datestamp', 'datetime')) && $field['settings']['repeat']) {
          $values[$entity_type][$bundle][] = $field_name;
        }
      }
    }
  }
  return $values;
}

/**
 * Helper function to figure out the bundle name for an entity.
 */
function date_get_entity_bundle($entity_type, $entity) {
  switch ($entity_type) {
    case 'field_collection_item':
      $bundle = $entity->field_name;
      break;
    default:
      $bundle = field_extract_bundle($entity_type, $entity);
      break;
  }
  // If there is no bundle name, field_info() uses the entity name as the bundle name in its arrays.
  if (empty($bundle)) {
    $bundle = $entity_type;
  }
  return $bundle;
}

function date_is_repeat_field($field, $instance = NULL) {
  if (is_string($field)) {
    $field = field_info_field($field);
  }

  if (!isset($field['settings']['repeat'])) {
    return FALSE;
  }

  $value = $field['settings']['repeat'];

  // This might be either a field form or a real field.
  if (is_array($value)) {
    return $value['#value'];
  }
  else {
    return $value;
  }
}

function date_default_format($type) {
  if (stristr($type, 'date_popup') && module_exists('date_popup')) {
    $formats = date_popup_formats();
    $default_format = array_shift($formats);
  }
  else {
    // example input formats must show all possible date parts, so add seconds.
    $default_format = str_replace('i', 'i:s', variable_get('date_format_short', 'm/d/Y - H:i'));
  }
  return $default_format;
}

function date_input_date($field, $instance, $element, $input) {
  switch ($instance['widget']['type']) {
    case 'date_text':
      $function = 'date_text_input_date';
      break;
    case 'date_popup':
      $function = 'date_popup_input_date';
      break;
    default:
      $function = 'date_select_input_date';
  }
  return $function($element, $input);
}

/**
 * A helper function to check if the all day flag is set on the parent of an
 * element, and adjust the date_format accordingly so the missing time will
 * not cause validation errors.
 */
function date_all_day_value(&$element, $form_state) {
  if (!empty($element['#date_all_day_id'])) {
    $parents = $element['#parents'];
    array_pop($parents);
    $parent_element = drupal_array_get_nested_value($form_state['values'], $parents);
    if (!empty($parent_element) && !empty($parent_element['all_day'])) {
      $element['#date_format'] = date_part_format('date', $element['#date_format']);
      return $parent_element['all_day'];
    }
  }
  return FALSE;
}

/**
 * Implements hook_theme().
 */
function date_theme() {
  $path = drupal_get_path('module', 'date');
  module_load_include('theme', 'date', 'date');

  $base = array(
    'file' => 'date.theme',
    'path' => "$path",
  );
  $themes = array(
    'date_combo' => $base + array('render element' => 'element'),
    'date_text_parts' => $base + array('render element' => 'element'),
    'date' => $base + array('render element' => 'element'),
    'date_all_day' => $base + array(
      'variables' => array(
        'field' => NULL,
        'instance' => NULL,
        'which' => NULL,
        'date1' => NULL,
        'date2' => NULL,
        'format' => NULL,
        'entity_type' => NULL,
        'entity' => NULL,
        'view' => NULL
      )
    ),
    'date_all_day_label' => $base + array('variables' => array()),
    'date_display_single' => $base + array('variables' => array(
        'date' => NULL,
        'timezone' => NULL,
        'dates' => NULL,
        'attributes' => array(),
        'rdf_mapping' => NULL,
        'add_rdf' => NULL,
    )),
    'date_display_range' => $base + array(
      'variables' => array(
        'date1' => NULL,
        'date2' => NULL,
        'timezone' => NULL,
        'dates' => NULL,
        // HTML attributes that will be applied to both the start and end dates
        // (unless overridden).
        'attributes' => array(),
        // HTML attributes that will be applied to the start date only.
        'attributes_start' => array(),
        // HTML attributes that will be applied to the end date only.
        'attributes_end' => array(),
        'rdf_mapping' => NULL,
        'add_rdf' => NULL,
    )),
    'date_repeat_display' => $base + array(
      'variables' => array(
        'field' => NULL,
        'item' => NULL,
        'entity_type' => NULL,
        'entity' => NULL,
        'dates' => NULL
      ),
      'function' => 'theme_date_repeat_display',
    ),
    'date_display_combination' => $base + array(
      'variables' => array(
        'entity_type' => NULL,
        'entity' => NULL,
        'field' => NULL,
        'instance' => NULL,
        'langcode' => NULL,
        'item' => NULL,
        'delta' => NULL,
        'display' => NULL,
        'dates' => NULL,
        'attributes' => array(),
        'rdf_mapping' => NULL,
        'add_rdf' => NULL,
      ),
    ),
    'date_display_interval' => $base + array(
      'variables' => array(
        'entity_type' => NULL,
        'entity' => NULL,
        'field' => NULL,
        'instance' => NULL,
        'langcode' => NULL,
        'item' => NULL,
        'delta' => NULL,
        'display' => NULL,
        'dates' => NULL,
        'attributes' => array(),
        'rdf_mapping' => NULL,
        'add_rdf' => NULL,
       ),
    ),
  );

  return $themes;
}

/**
 * Implements hook_element_info().
 *
 * date_combo will create a 'start' and optional 'end' date, along with
 * an optional 'timezone' column for date-specific timezones. Each
 * 'start' and 'end' date will be constructed from date_select or date_text.
 */
function date_element_info() {
  $type = array();
  $type['date_combo'] = array(
    '#input' => TRUE,
    '#delta' => 0,
    '#columns' => array('value', 'value2', 'timezone', 'offset', 'offset2'),
    '#process' => array('date_combo_element_process'),
    '#element_validate' => array('date_combo_validate'),
    '#theme_wrappers' => array('date_combo'),
  );
  if (module_exists('ctools')) {
    $type['date_combo']['#pre_render'] = array('ctools_dependent_pre_render');
  }
  return $type;
}

/**
 * Helper function for creating formatted date arrays from a formatter.
 *
 * Use the Date API to get an object representation of a date field
 *
 * @param array $field
 * @param array $item - a entity field item, like $entity->myfield[0]
 *
 * @return array that holds the Start and End date objects
 *  Each date object looks like:
 *       date [value] => array (
 *         [db] => array (  // the value stored in the database
 *           [object] => the datetime object
 *           [datetime] => 2007-02-15 20:00:00
 *         )
 *         [local] => array (  // the local representation of that value
 *           [object] => the datetime object
 *           [datetime] => 2007-02-15 14:00:00
 *           [timezone] => US/Central
 *           [offset] => -21600
 *         )
 *      )
 */
function date_formatter_process($formatter, $entity_type, $entity, $field, $instance, $langcode, $item, $display) {
  $dates = array();
  $timezone = date_default_timezone();
  if (empty($timezone)) {
    return $dates;
  }

  $granularity = date_granularity($field);
  $settings = $display['settings'];
  $field_name = $field['field_name'];
  $format = date_formatter_format($formatter, $settings, $granularity, $langcode);
  $timezone = isset($item['timezone']) ? $item['timezone'] : '';
  $timezone = date_get_timezone($field['settings']['tz_handling'], $timezone);
  $timezone_db = date_get_timezone_db($field['settings']['tz_handling']);
  $process = date_process_values($field);
  foreach ($process as $processed) {
    if (empty($item[$processed])) {
      $dates[$processed] = NULL;
    }
    else {
      // create a date object with a gmt timezone from the database value
      $value = $item[$processed];
      $db_format = date_type_format($field['type']);
      $date = new DateObject($value, $timezone_db, $db_format);
      $date->limitGranularity($field['settings']['granularity']);

      $dates[$processed] = array();
      $dates[$processed]['db']['object'] = $date;
      $dates[$processed]['db']['datetime'] = date_format($date, DATE_FORMAT_DATETIME);

      date_timezone_set($date, timezone_open($timezone));
      $dates[$processed]['local']['object'] = $date;
      $dates[$processed]['local']['datetime'] = date_format($date, DATE_FORMAT_DATETIME);
      $dates[$processed]['local']['timezone'] = $timezone;
      $dates[$processed]['local']['offset'] = date_offset_get($date);

      //format the date, special casing the 'interval' format which doesn't need to be processed
      $dates[$processed]['formatted'] = '';
      $dates[$processed]['formatted_iso'] = date_format_date($date, 'custom', 'c');
      if (is_object($date)) {
        if ($format == 'format_interval') {
           $dates[$processed]['interval'] = date_format_interval($date);
        }
        elseif ($format == 'format_calendar_day') {
           $dates[$processed]['calendar_day'] = date_format_calendar_day($date);
        }
        elseif ($format == 'U') {
          $dates[$processed]['formatted'] = date_format_date($date, 'custom', $format);
          $dates[$processed]['formatted_date'] = date_format_date($date, 'custom', $format);
          $dates[$processed]['formatted_time'] = '';
          $dates[$processed]['formatted_timezone'] = '';
        }
        elseif (!empty($format)) {
          $dates[$processed]['formatted'] = date_format_date($date, 'custom', $format);
          $dates[$processed]['formatted_date'] = date_format_date($date, 'custom', date_limit_format($format, array('year', 'month', 'day')));
          $dates[$processed]['formatted_time'] = date_format_date($date, 'custom', date_limit_format($format, array('hour', 'minute', 'second')));
          $dates[$processed]['formatted_timezone'] = date_format_date($date, 'custom', date_limit_format($format, array('timezone')));
        }
      }
    }
  }
  if (empty($dates['value2'])) {
    $dates['value2'] = $dates['value'];
  }
  $date1 = $dates['value']['local']['object'];
  $date2 = $dates['value2']['local']['object'];
  $is_all_day = date_field_all_day($field, $instance, $date1, $date2);

  $all_day1 = '';
  $all_day2 = '';
  if ($format != 'format_interval' && $is_all_day) {
    $all_day1 = theme('date_all_day', array(
      'field' => $field,
      'instance' => $instance,
      'which' => 'date1',
      'date1' => $date1,
      'date2' => $date2,
      'format' => $format,
      'entity_type' => $entity_type,
      'entity' => $entity));
    $all_day2 = theme('date_all_day', array(
      'field' => $field,
      'instance' => $instance,
      'which' => 'date2',
      'date1' => $date1,
      'date2' => $date2,
      'format' => $format,
      'entity_type' => $entity_type,
      'entity' => $entity));
    $dates['value']['formatted_time'] = theme('date_all_day_label');
    $dates['value2']['formatted_time'] = theme('date_all_day_label');
    $dates['value']['formatted'] = $all_day1;
    $dates['value2']['formatted'] = $all_day2;
  }
  $dates['format'] = $format;
  return $dates;
}

/**
 * $field['settings']['granularity'] will contain an array like ('hour' => 'hour', 'month' => 0)
 * where the values turned on return their own names and the values turned off return a zero
 * need to reconfigure this into a simple array of the turned on values
 */
function date_granularity($field) {
  if (!is_array($field) || !is_array($field['settings']['granularity'])) {
    $field['settings']['granularity'] = drupal_map_assoc(array('year', 'month', 'day'));
  }
  return array_values(array_filter($field['settings']['granularity']));
}

/**
 * Helper function to create an array of the date values in a
 * field that need to be processed.
 */
function date_process_values($field) {
  return $field['settings']['todate'] ? array('value', 'value2') : array('value');
}

/**
 * Implements hook_form_FORM_ID_alter().
 */
function date_form_field_ui_field_edit_form_alter(&$form, &$form_state, $form_id) {
  $field = $form['#field'];
  $instance = $form['#instance'];

  if (!in_array($field['type'], array('date', 'datetime', 'datestamp'))) {
    return;
  }

  // If using repeating dates, override the Field module's handling of the multiple values option.
  if (module_exists('date_repeat') && date_is_repeat_field($field, $instance)) {
    $form['field']['cardinality']['#disabled'] = TRUE;
    $form['field']['cardinality']['#value'] = FIELD_CARDINALITY_UNLIMITED;
  }

  // Reorganize the instance settings and widget settings sections into a more
  // intuitive combined fieldset.
  $form['instance']['defaults'] = array(
    '#type' => 'fieldset',
    '#title' => t('More settings and values'),
    '#collapsible' => TRUE,
    '#collapsed' => TRUE,
  );
  $form['instance']['date_format'] = array(
    '#type' => 'fieldset',
    '#title' => t('Date entry'),
    '#collapsible' => TRUE,
    '#collapsed' => FALSE,
  );
  $form['instance']['default_values'] = array(
    '#type' => 'fieldset',
    '#title' => t('Default values'),
    '#collapsible' => TRUE,
    '#collapsed' => FALSE,
  );
  $form['instance']['years_back_and_forward'] = array(
    '#type' => 'fieldset',
    '#title' => t('Starting and ending year'),
    '#collapsible' => TRUE,
    '#collapsed' => FALSE,
  );

  $form['instance']['#pre_render'][] = 'date_field_ui_field_edit_form_pre_render';
}

/**
 * Rearrange form elements into fieldsets for presentation only.
 */
function date_field_ui_field_edit_form_pre_render($form) {
  foreach ($form as $name => $element) {
    if (is_array($element) && isset($element['#fieldset'])) {
      $fieldset = $element['#fieldset'];
      $form[$fieldset][$name] = $element;
      unset($form[$name]);
    }
  }
  foreach (array('date_format', 'default_values', 'years_back_and_forward') as $name) {
    if (element_children($form[$name])) {
      // Force the items in the fieldset to be resorted now that the instance
      // and widget settings are combined.
      $form[$name]['#sorted'] = FALSE;
      $form['defaults'][$name] = $form[$name];
    }
    unset($form[$name]);
  }
  return $form;
}

/**
 * Implements hook_field_widget_error().
 */
function date_field_widget_error($element, $error, $form, &$form_state) {
  form_error($element[$error['error']], $error['message']);
}

/**
 * Retrieve a date format string from formatter settings.
 */
function date_formatter_format($formatter, $settings, $granularity = array(), $langcode = NULL) {
  $format_type = !empty($settings['format_type']) ? $settings['format_type'] : 'format_interval';

  switch ($formatter) {
    case 'format_interval':
      return 'format_interval';
      break;
    case 'date_plain':
      return 'date_plain';
      break;
    default:
      return date_format_type_format($format_type, $langcode);
      break;
  }

  // A selected format might include timezone information.
  array_push($granularity, 'timezone');
  return date_limit_format($format, $granularity);
}

/**
 * Helper function to get the right format for a format type.
 * Checks for locale-based format first.
 */
function date_format_type_format($format_type, $langcode = NULL) {
  $format = system_date_format_locale($langcode, $format_type);

  // If locale enabled and $format_type inexistent in {date_format_locale}
  // we receive (due to inconsistency of core api) an array of all (other)
  // formats available for $langcode in locale table.
  // However there's no guarantee that the key $format_type exists.
  // See http://drupal.org/node/1302358.
  if (!is_string($format)) {
    // If the configuration page at admin/config/regional/date-time was
    // never saved, the default core date format variables
    // ('date_format_short', 'date_format_medium', and 'date_format_long')
    // will not be stored in the database, so we have to define their
    // expected defaults here.
    switch ($format_type) {
      case 'short':
        $default = 'm/d/Y - H:i';
        break;
      case 'long':
        $default = 'l, F j, Y - H:i';
        break;
      // If it's not one of the core date types and isn't stored in the
      // database, we'll fall back on using the same default format as the
      // 'medium' type.
      case 'medium':
      default:
        // @todo: If a non-core module provides a date type and does not
        //   variable_set() a default for it, the default assumed here may
        //   not be correct (since the default format used by 'medium' may
        //   not even be one of the allowed formats for the date type in
        //   question). To fix this properly, we should really call
        //   system_get_date_formats($format_type) and take the first
        //   format from that list as the default. However, this function
        //   is called often (on many different page requests), so calling
        //   system_get_date_formats() from here would be a performance hit
        //   since that function writes several records to the database
        //   during each page request that calls it.
        $default = 'D, m/d/Y - H:i';
        break;
    }
    $format = variable_get('date_format_'. $format_type, $default);
  }
  return $format;
}

/**
 * Helper function to adapt entity date fields to formatter settings.
 */
function date_prepare_entity($formatter, $entity_type, $entity, $field, $instance, $langcode, $item, $display) {

  // If there are options to limit multiple values,
  // alter the entity values to match.
  $field_name = $field['field_name'];
  $options = $display['settings'];
  $max_count = $options['multiple_number'];

  // If no results should be shown, empty the values and return.
  if (is_numeric($max_count) && $max_count == 0) {
    $entity->{$field_name} = array();
    return $entity;
  }

  // Otherwise removed values that should not be displayed.
  if (!empty($options['multiple_from']) || !empty($options['multiple_to']) || !empty($max_count)) {
    $format = date_type_format($field['type']);
    include_once(drupal_get_path('module', 'date_api') . '/date_api_sql.inc');
    $date_handler = new date_sql_handler($field);
    $arg0 = !empty($options['multiple_from']) ? $date_handler->arg_replace($options['multiple_from']) : variable_get('date_min_year', 100) . '-01-01T00:00:00';
    $arg1 = !empty($options['multiple_to']) ? $date_handler->arg_replace($options['multiple_to']) : variable_get('date_max_year', 4000) . '-12-31T23:59:59';
    if (!empty($arg0) && !empty($arg1)) {
      $arg = $arg0 . '--' . $arg1;
    }
    elseif (!empty($arg0)) {
      $arg = $arg0;
    }
    elseif (!empty($arg1)) {
      $arg = $arg1;
    }
    if (!empty($arg)) {
      $range = $date_handler->arg_range($arg);
      $start = date_format($range[0], $format);
      $end = date_format($range[1], $format);
      // Empty out values we don't want to see.
      $count = 0;
      foreach ($entity->{$field_name}[$langcode] as $delta => $value) {
        if (!empty($entity->date_repeat_show_all)) {
          break;
        }
        elseif ((!empty($max_count) && is_numeric($max_count) && $count >= $max_count) ||
          (!empty($value['value'])  && $value['value'] < $start) ||
          (!empty($value['value2']) && $value['value2'] > $end)) {
            unset($entity->{$field_name}[$langcode][$delta]);
        }
        else {
          $count++;
        }
      }
    }
  }

  return $entity;
}

/**
 * Generate a DateAPI SQL handler for the given CCK date field.
 *
 * The handler will be set up to make the correct timezone adjustments
 * for the field settings.
 *
 * @param $field
 *  - a $field array.
 * @param $compare_tz
 *  - the timezone used for comparison values in the SQL.
 */
 function date_field_get_sql_handler($field, $compare_tz = NULL) {
   module_load_include('inc', 'date_api', 'date_api_sql');

   $db_info = date_api_database_info($field);

   // Create a DateAPI SQL handler class for this field type.
   $handler = new date_sql_handler($field['type']);

   // If this date field stores a timezone in the DB, tell the handler about it.
   if ($field['settings']['tz_handling'] == 'date') {
     $handler->db_timezone_field = $db_info['columns']['timezone']['column'];
   }
   else {
     $handler->db_timezone = date_get_timezone_db($field['settings']['tz_handling']);
   }

   if (empty($compare_tz)) {
     $compare_tz = date_get_timezone($field['settings']['tz_handling']);
   }
   $handler->local_timezone = $compare_tz;

  // Now that the handler is properly initialized, force the DB
  // to use UTC so no timezone conversions get added to things like
  // NOW() or FROM_UNIXTIME().
  $handler->set_db_timezone();

  return $handler;
}

/**
 * Callback to alter the property info of date fields.
 *
 * @see date_field_info()
 */
function date_entity_metadata_property_info_alter(&$info, $entity_type, $field, $instance, $field_type) {
  $name = $field['field_name'];
  $property = &$info[$entity_type]['bundles'][$instance['bundle']]['properties'][$name];

  if ($field['type'] != 'datestamp' || $field['settings']['timezone_db'] != 'UTC') {
    // Add a getter callback to convert the date into the right format.
    $property['getter callback'] = 'date_entity_metadata_field_getter';
    $property['setter callback'] = 'date_entity_metadata_field_setter';
    unset($property['query callback']);
  }
  if (!empty($field['settings']['todate'])) {
    // Define a simple data structure containing both dates.
    $property['type'] = ($field['cardinality'] != 1) ? 'list<struct>' : 'struct';
    $property['getter callback'] = 'entity_metadata_field_verbatim_get';
    $property['setter callback'] = 'entity_metadata_field_verbatim_set';
    $property['property info'] = array(
      'value' => array(
        'type' => 'date',
        'label' => t('Start date'),
        'getter callback' => 'date_entity_metadata_struct_getter',
        'setter callback' => 'date_entity_metadata_struct_setter',
        // The getter and setter callbacks for 'value' and 'value2'
        // will not provide the field name as $name, we'll add it to $info.
        'field_name' => $field['field_name'],
      ),
      'value2' => array(
        'type' => 'date',
        'label' => t('End date'),
        'getter callback' => 'date_entity_metadata_struct_getter',
        'setter callback' => 'date_entity_metadata_struct_setter',
        // The getter and setter callbacks for 'value' and 'value2'
        // will not provide the field name as $name, we'll add it to $info.
        'field_name' => $field['field_name'],
      ),
      'duration' => array(
        'type' => 'duration',
        'label' => t('Duration'),
        'desription' => t('The duration of the time period given by the dates.'),
        'getter callback' => 'date_entity_metadata_duration_getter',
        // No setter callback for duration.
        // The getter callback for duration will not provide the field name
        // as $name, we'll add it to $info.
        'field_name' => $field['field_name'],
      ),
    );
    unset($property['query callback']);
  }
}

/**
 * Getter callback to return date values as datestamp in UTC from the field.
 */
function date_entity_metadata_field_getter($entity, array $options, $name, $entity_type, &$context) {

  $return = entity_metadata_field_verbatim_get($entity, $options, $name, $entity_type, $context);
  $items = ($context['field']['cardinality'] == 1) ? array($return) : $return;
  foreach ($items as $key => $item) {
    $items[$key] = date_entity_metadata_struct_getter($item, $options, 'value', 'struct', $context);
  }
  return ($context['field']['cardinality'] == 1) ? $items[0] : $items;
}

/**
 * Getter callback to return date values as datestamp in UTC.
 */
function date_entity_metadata_struct_getter($item, array $options, $name, $type, $info) {
  $value = trim($item[$name]);
  if (empty($value)) {
    return NULL;
  }
  $timezone_db = !empty($item['timezone_db']) ? $item['timezone_db'] : 'UTC';
  $date = new DateObject($value, $timezone_db);
  return !empty($date) ? date_format_date($date, 'custom', 'U') : NULL;
}

/**
 * Getter callback to return the duration of the time period given by the dates.
 */
function date_entity_metadata_duration_getter($item, array $options, $name, $type, $info) {
  $value = date_entity_metadata_struct_getter($item, $options, 'value', 'struct', $info);
  $value2 = date_entity_metadata_struct_getter($item, $options, 'value2', 'struct', $info);
  if ($value && $value2) {
    return $value2 - $value;
  }
}

/**
 * Callback for setting field property values.
 *
 * Based on entity_metadata_field_property_set(), the original property setter,
 * adapted to transform non-timestamp date values to timestamps.
 */
function date_entity_metadata_field_setter(&$entity, $name, $value, $langcode, $entity_type, $info) {
  $field = field_info_field($name);
  if (!isset($langcode)) {
    // Try to figure out the default language used by the entity.
    // @todo: Update once http://drupal.org/node/1260640 has been fixed.
    $langcode = isset($entity->language) ? $entity->language : LANGUAGE_NONE;
  }
  $values = $field['cardinality'] == 1 ? array($value) : (array) $value;

  $items = array();
  foreach ($values as $delta => $value) {
    // Make use of the struct setter to convert the date back to a timestamp.
    $info['field_name'] = $name;
    date_entity_metadata_struct_setter($items[$delta], 'value', $value, $langcode, 'struct', $info);
  }
  $entity->{$name}[$langcode] = $items;
  // Empty the static field language cache, so the field system picks up any
  // possible new languages.
  drupal_static_reset('field_language');
}

/**
 * Callback for setting an individual field value if a to-date may be there too.
 * Based on entity_property_verbatim_set().
 *
 * The passed in unix timestamp (UTC) is converted to the right value and
 * format dependent on the field.
 *
 * $name is either 'value' or 'value2'.
 */
function date_entity_metadata_struct_setter(&$item, $name, $value, $langcode, $type, $info) {

  if (!isset($value)) {
    $item[$name] = NULL;
  }
  else {
    $field = field_info_field($info['field_name']);
    $format = date_type_format($field['type']);
    $timezone_db = date_get_timezone_db($field['settings']['tz_handling']);

    $date = new DateObject($value, 'UTC');
    if ($timezone_db != 'UTC') {
      date_timezone_set($date, timezone_open($timezone_db));
    }
    $item[$name] = $date->format($format);
  }
}

/**
 * Determine if a Start/End date combination qualify as 'All day'.
 *
 * @param array $field, the field definition for this date field.
 * @param object $date1, a date/time object for the 'Start' date.
 * @param object $date2, a date/time object for the 'End' date.
 * @return TRUE or FALSE.
 */
function date_field_all_day($field, $instance, $date1, $date2 = NULL) {
  if (empty($date1) || !is_object($date1)) {
    return FALSE;
  }
  elseif (!date_has_time($field['settings']['granularity'])) {
    return TRUE;
  }
  if (empty($date2)) {
    $date2 = $date1;
  }

  $granularity = date_granularity_precision($field['settings']['granularity']);
  $increment = isset($instance['widget']['settings']['increment']) ? $instance['widget']['settings']['increment'] : 1;
  return date_is_all_day(date_format($date1, DATE_FORMAT_DATETIME), date_format($date2, DATE_FORMAT_DATETIME), $granularity, $increment);

}