path: root/includes/form.inc

<?php
// $Id$

/**
 * @defgroup forms Form builder functions
 * @{
 * Functions that build an abstract representation of a HTML form.
 *
 * All modules should declare their form builder functions to be in this
 * group and each builder function should reference its validate and submit
 * functions using \@see. Conversely, validate and submit functions should
 * reference the form builder function using \@see. For examples, of this see
 * system_modules_uninstall() or user_pass(), the latter of which has the
 * following in its doxygen documentation:
 *
 * \@ingroup forms
 * \@see user_pass_validate().
 * \@see user_pass_submit().
 *
 * @} End of "defgroup forms".
 */

/**
 * @defgroup form_api Form generation
 * @{
 * Functions to enable the processing and display of HTML forms.
 *
 * Drupal uses these functions to achieve consistency in its form processing and
 * presentation, while simplifying code and reducing the amount of HTML that
 * must be explicitly generated by modules.
 *
 * The drupal_get_form() function handles retrieving and processing an HTML
 * form for modules automatically. For example:
 *
 * @code
 *   // Display the user registration form.
 *   $output = drupal_get_form('user_register_form');
 * @endcode
 *
 * Forms can also be built and submitted programmatically without any user input
 * using the drupal_form_submit() function.
 *
 * For information on the format of the structured arrays used to define forms,
 * and more detailed explanations of the Form API workflow, see the
 * @link http://api.drupal.org/api/file/developer/topics/forms_api_reference.html reference @endlink
 * and the @link http://api.drupal.org/api/file/developer/topics/forms_api.html quickstart guide. @endlink
 */

/**
 * Wrapper for drupal_build_form() for use when $form_state is not needed.
 *
 * @param $form_id
 *   The unique string identifying the desired form. If a function with that
 *   name exists, it is called to build the form array. Modules that need to
 *   generate the same form (or very similar forms) using different $form_ids
 *   can implement hook_forms(), which maps different $form_id values to the
 *   proper form constructor function. Examples may be found in node_forms(),
 *   search_forms(), and user_forms().
 * @param ...
 *   Any additional arguments are passed on to the functions called by
 *   drupal_get_form(), including the unique form constructor function. For
 *   example, the node_edit form requires that a node object is passed in here
 *   when it is called.
 * @return
 *   The form array.
 *
 * @see drupal_build_form()
 */
function drupal_get_form($form_id) {
  $form_state = array();

  $args = func_get_args();
  // Remove $form_id from the arguments.
  array_shift($args);
  $form_state['build_info']['args'] = $args;

  return drupal_build_form($form_id, $form_state);
}

/**
 * Build and process a form based on a form id.
 *
 * The form may also be retrieved from the cache if the form was built in a
 * previous page-load. The form is then passed on for processing, validation
 * and submission if there is proper input.
 *
 * @param $form_id
 *   The unique string identifying the desired form. If a function with that
 *   name exists, it is called to build the form array. Modules that need to
 *   generate the same form (or very similar forms) using different $form_ids
 *   can implement hook_forms(), which maps different $form_id values to the
 *   proper form constructor function. Examples may be found in node_forms(),
 *   search_forms(), and user_forms().
 * @param &$form_state
 *   An array which stores information about the form. This is passed as a
 *   reference so that the caller can use it to examine what in the form changed
 *   when the form submission process is complete. Furthermore, it may be used
 *   to store information related to the processed data in the form, which will
 *   persist across page requests when the 'cache' or 'rebuild' flag is set.
 *   The following parameters may be set in $form_state to affect how the form
 *   is rendered:
 *   - build_info: A keyed array of build information that is necessary to
 *     rebuild the form from cache when the original context may no longer be
 *     available:
 *     - args: An array of arguments to pass to the form builder.
 *     - file: An optional include file that contains the form and is
 *       automatically loaded by form_get_cache(). Defaults to the current menu
 *       router item's 'file' definition, if existent.
 *   - rebuild: Normally, after the entire form processing is completed and
 *     submit handlers ran, a form is considered to be done and
 *     drupal_redirect_form() will redirect the user to a new page using a GET
 *     request (so a browser refresh does not re-submit the form). However, if
 *     'rebuild' has been set to TRUE, then a new copy of the form is
 *     immediately built and sent to the browser; instead of a redirect. This is
 *     used for multi-step forms, such as wizards and confirmation forms. Also,
 *     if a form validation handler has set 'rebuild' to TRUE and a validation
 *     error occurred, then the form is rebuilt prior to being returned,
 *     enabling form elements to be altered, as appropriate to the particular
 *     validation error.
 *   - input: An array of input that corresponds to $_POST or $_GET, depending
 *     on the 'method' chosen (see below).
 *   - method: The HTTP form method to use for finding the input for this form.
 *     May be 'post' or 'get'. Defaults to 'post'. Note that 'get' method
 *     forms do not use form ids so are always considered to be submitted, which
 *     can have unexpected effects. The 'get' method should only be used on
 *     forms that do not change data, as that is exclusively the domain of post.
 *   - no_redirect: If set to TRUE the form will NOT perform a drupal_goto(),
 *     even if 'redirect' is set.
 *   - cache: If set to TRUE the original, unprocessed form structure will be
 *     cached, which allows to rebuild the entire form from cache.
 *   - no_cache: If set to TRUE the form will NOT be cached, even if 'cache' is
 *     set.
 *   - always_process: If TRUE and the method is GET, a form_id is not
 *     necessary. This should only be used on RESTful GET forms that do NOT
 *     write data, as this could lead to security issues. It is useful so that
 *     searches do not need to have a form_id in their query arguments to
 *     trigger the search.
 *   - must_validate: Ordinarily, a form is only validated once but there are
 *     times when a form is resubmitted internally and should be validated
 *     again. Setting this to TRUE will force that to happen. This is most
 *     likely to occur during AHAH or AJAX operations.
 *   - temporary: An array holding temporary data accessible during the current
 *     page request only. It may be used to temporary save any data that doesn't
 *     need to or shouldn't be cached during the whole form workflow, e.g. data
 *     that needs to be accessed during the current form build process only.
 *   - wrapper_callback: Modules that wish to pre-populate certain forms with
 *     common elements, such as back/next/save buttons in multi-step form
 *     wizards, may define a form builder function name that returns a form
 *     structure, which is passed on to the actual form builder function.
 *     Such implementations may either define the 'wrapper_callback' via
 *     hook_forms() or have to invoke drupal_build_form() (instead of
 *     drupal_get_form()) on their own in a custom menu callback to prepare
 *     $form_state accordingly.
 *   Further $form_state properties controlling the redirection behavior after
 *   form submission may be found in drupal_redirect_form().
 *
 * @return
 *   The rendered form or NULL, depending upon the $form_state flags that were set.
 *
 * @see drupal_redirect_form()
 */
function drupal_build_form($form_id, &$form_state) {
  // Ensure some defaults; if already set they will not be overridden.
  $form_state += form_state_defaults();

  if (!isset($form_state['input'])) {
    $form_state['input'] = $form_state['method'] == 'get' ? $_GET : $_POST;
  }

  if (isset($_SESSION['batch_form_state'])) {
    // We've been redirected here after a batch processing : the form has
    // already been processed, so we grab the post-process $form_state value
    // and move on to form display. See _batch_finished() function.
    $form_state = $_SESSION['batch_form_state'];
    unset($_SESSION['batch_form_state']);
  }
  else {
    // If the incoming input contains a form_build_id, we'll check the
    // cache for a copy of the form in question. If it's there, we don't
    // have to rebuild the form to proceed. In addition, if there is stored
    // form_state data from a previous step, we'll retrieve it so it can
    // be passed on to the form processing code.
    if (isset($form_state['input']['form_id']) && $form_state['input']['form_id'] == $form_id && !empty($form_state['input']['form_build_id'])) {
      $form_build_id = $form_state['input']['form_build_id'];
      $form = form_get_cache($form_build_id, $form_state);
    }

    // If the previous bit of code didn't result in a populated $form
    // object, we're hitting the form for the first time and we need
    // to build it from scratch.
    if (!isset($form)) {
      // Record the filepath of the include file containing the original form,
      // so the form builder callbacks can be loaded when the form is being
      // rebuilt from cache on a different path (such as 'system/ajax').
      // @see form_get_cache()
      // menu_get_item() is not available at installation time.
      if (!isset($form_state['build_info']['file']) && !defined('MAINTENANCE_MODE')) {
        $item = menu_get_item();
        if (!empty($item['file'])) {
          $form_state['build_info']['file'] = $item['file'];
        }
      }

      $form = drupal_retrieve_form($form_id, $form_state);
      $form_build_id = 'form-' . md5(uniqid(mt_rand(), TRUE));
      $form['#build_id'] = $form_build_id;

      // Fix the form method, if it is 'get' in $form_state, but not in $form.
      if ($form_state['method'] == 'get' && !isset($form['#method'])) {
        $form['#method'] = 'get';
      }

      drupal_prepare_form($form_id, $form, $form_state);
      // Store a copy of the unprocessed form to cache in case
      // $form_state['cache'] is set.
      $original_form = $form;
    }

    // Now that we know we have a form, we'll process it (validating,
    // submitting, and handling the results returned by its submission
    // handlers. Submit handlers accumulate data in the form_state by
    // altering the $form_state variable, which is passed into them by
    // reference.
    drupal_process_form($form_id, $form, $form_state);
  }

  // Most simple, single-step forms will be finished by this point --
  // drupal_process_form() usually redirects to another page (or to
  // a 'fresh' copy of the form) once processing is complete. If one
  // of the form's handlers has set $form_state['redirect'] to FALSE,
  // the form will simply be re-rendered with the values still in its
  // fields.
  //
  // If $form_state['rebuild'] has been set and input has been processed, we
  // know that we're in a multi-part process of some sort and the form's
  // workflow is not complete. We need to construct a fresh copy of the form,
  // passing in the latest $form_state in addition to any other variables passed
  // into drupal_get_form().
  if ($form_state['rebuild'] && $form_state['process_input'] && !form_get_errors()) {
    $form = drupal_rebuild_form($form_id, $form_state);
  }
  // After processing the form, the form builder or a #process callback may
  // have set $form_state['cache'] to indicate that the original form and the
  // $form_state shall be cached. But the form may only be cached if the
  // special 'no_cache' property is not set to TRUE and we are not rebuilding.
  elseif (isset($form_build_id) && $form_state['cache'] && empty($form_state['no_cache'])) {
    // Cache the original, unprocessed form upon initial build of the form.
    if (isset($original_form)) {
      form_set_cache($form_build_id, $original_form, $form_state);
    }
    // After processing a cached form, only update the cached form state.
    else {
      form_set_cache($form_build_id, NULL, $form_state);
    }
  }

  // Don't override #theme if someone already set it.
  if (!isset($form['#theme'])) {
    drupal_theme_initialize();
    $registry = theme_get_registry();
    if (isset($registry[$form_id])) {
      $form['#theme'] = $form_id;
    }
  }

  return $form;
}

/**
 * Retrieve default values for the $form_state array.
 */
function form_state_defaults() {
  return array(
    'rebuild' => FALSE,
    'redirect' => NULL,
    'build_info' => array('args' => array()),
    'temporary' => array(),
    'submitted' => FALSE,
    'programmed' => FALSE,
    'cache'=> FALSE,
    'method' => 'post',
    'groups' => array(),
  );
}

/**
 * Retrieves a form, caches it and processes it again.
 *
 * If your AHAH callback simulates the pressing of a button, then your AHAH
 * callback will need to do the same as what drupal_get_form would do when the
 * button is pressed: get the form from the cache, run drupal_process_form over
 * it and then if it needs rebuild, run drupal_rebuild_form over it. Then send
 * back a part of the returned form.
 * $form_state['clicked_button']['#array_parents'] will help you to find which
 * part.
 *
 * @param $form_id
 *   The unique string identifying the desired form. If a function
 *   with that name exists, it is called to build the form array.
 *   Modules that need to generate the same form (or very similar forms)
 *   using different $form_ids can implement hook_forms(), which maps
 *   different $form_id values to the proper form constructor function. Examples
 *   may be found in node_forms(), search_forms(), and user_forms().
 * @param $form_state
 *   A keyed array containing the current state of the form.
 * @param $form_build_id
 *   If the AHAH callback calling this function only alters part of the form,
 *   then pass in the existing form_build_id so we can re-cache with the same
 *   csid.
 * @return
 *   The newly built form.
 */
function drupal_rebuild_form($form_id, &$form_state, $form_build_id = NULL) {
  // AJAX and other contexts may call drupal_rebuild_form() even when
  // $form_state['rebuild'] isn't set, but _form_builder_handle_input_element()
  // needs to distinguish a rebuild from an initial build in order to process
  // user input correctly. Form constructors and form processing functions may
  // also need to handle a rebuild differently than an initial build.
  $form_state['rebuild'] = TRUE;

  $form = drupal_retrieve_form($form_id, $form_state);

  if (!isset($form_build_id)) {
    // We need a new build_id for the new version of the form.
    $form_build_id = 'form-' . md5(mt_rand());
  }
  $form['#build_id'] = $form_build_id;
  drupal_prepare_form($form_id, $form, $form_state);

  if (empty($form_state['no_cache'])) {
    // We cache the form structure and the form state so it can be retrieved
    // later for validation.
    form_set_cache($form_build_id, $form, $form_state);
  }

  // Clear out all group associations as these might be different when
  // re-rendering the form.
  $form_state['groups'] = array();

  // Do not call drupal_process_form(), since it would prevent the rebuilt form
  // to submit.
  $form = form_builder($form_id, $form, $form_state);
  return $form;
}

/**
 * Fetch a form from cache.
 */
function form_get_cache($form_build_id, &$form_state) {
  if ($cached = cache_get('form_' . $form_build_id, 'cache_form')) {
    $form = $cached->data;

    global $user;
    if ((isset($form['#cache_token']) && drupal_valid_token($form['#cache_token'])) || (!isset($form['#cache_token']) && !$user->uid)) {
      if ($cached = cache_get('form_state_' . $form_build_id, 'cache_form')) {
        // Re-populate $form_state for subsequent rebuilds.
        $form_state = $cached->data + $form_state;

        // If the original form is contained in an include file, load the file.
        // @see drupal_build_form()
        if (!empty($form_state['build_info']['file']) && file_exists($form_state['build_info']['file'])) {
          require_once DRUPAL_ROOT . '/' . $form_state['build_info']['file'];
        }
      }
      return $form;
    }
  }
}

/**
 * Store a form in the cache.
 */
function form_set_cache($form_build_id, $form, $form_state) {
  // 6 hours cache life time for forms should be plenty.
  $expire = 21600;

  // Cache form structure.
  if (isset($form)) {
    if ($GLOBALS['user']->uid) {
      $form['#cache_token'] = drupal_get_token();
    }
    cache_set('form_' . $form_build_id, $form, 'cache_form', REQUEST_TIME + $expire);
  }

  // Cache form state.
  if ($data = array_diff_key($form_state, array_flip(form_state_keys_no_cache()))) {
    cache_set('form_state_' . $form_build_id, $data, 'cache_form', REQUEST_TIME + $expire);
  }
}

/**
 * Returns an array of $form_state keys that shouldn't be cached.
 */
function form_state_keys_no_cache() {
  return array(
    // Public properties defined by form constructors and form handlers.
    'always_process',
    'must_validate',
    'rebuild',
    'redirect',
    'no_redirect',
    'temporary',
    // Internal properties defined by form processing.
    'buttons',
    'clicked_button',
    'complete form',
    'groups',
    'input',
    'method',
    'submit_handlers',
    'submitted',
    'validate_handlers',
    'values',
  );
}

/**
 * Retrieves a form using a form_id, populates it with $form_state['values'],
 * processes it, and returns any validation errors encountered. This
 * function is the programmatic counterpart to drupal_get_form().
 *
 * @param $form_id
 *   The unique string identifying the desired form. If a function
 *   with that name exists, it is called to build the form array.
 *   Modules that need to generate the same form (or very similar forms)
 *   using different $form_ids can implement hook_forms(), which maps
 *   different $form_id values to the proper form constructor function. Examples
 *   may be found in node_forms(), search_forms(), and user_forms().
 * @param $form_state
 *   A keyed array containing the current state of the form. Most important is
 *   the $form_state['values'] collection, a tree of data used to simulate the
 *   incoming $_POST information from a user's form submission. If a key is not
 *   filled in $form_state['values'], then the default value of the respective
 *   element is used. To submit an unchecked checkbox or other control that
 *   browsers submit by not having a $_POST entry, include the key, but set the
 *   value to NULL.
 * @param ...
 *   Any additional arguments are passed on to the functions called by
 *   drupal_form_submit(), including the unique form constructor function.
 *   For example, the node_edit form requires that a node object be passed
 *   in here when it is called.
 * For example:
 *
 * @code
 * // register a new user
 * $form_state = array();
 * $form_state['values']['name'] = 'robo-user';
 * $form_state['values']['mail'] = 'robouser@example.com';
 * $form_state['values']['pass']['pass1'] = 'password';
 * $form_state['values']['pass']['pass2'] = 'password';
 * $form_state['values']['op'] = t('Create new account');
 * drupal_form_submit('user_register_form', $form_state);
 *
 * // Create a new node
 * $form_state = array();
 * module_load_include('inc', 'node', 'node.pages');
 * $node = array('type' => 'story');
 * $form_state['values']['title'] = 'My node';
 * $form_state['values']['body'] = 'This is the body text!';
 * $form_state['values']['name'] = 'robo-user';
 * $form_state['values']['op'] = t('Save');
 * drupal_form_submit('story_node_form', $form_state, (object)$node);
 * @endcode
 */
function drupal_form_submit($form_id, &$form_state) {
  if (!isset($form_state['build_info']['args'])) {
    $args = func_get_args();
    array_shift($args);
    array_shift($args);
    $form_state['build_info']['args'] = $args;
  }
  // Merge in default values.
  $form_state += form_state_defaults();

  $form = drupal_retrieve_form($form_id, $form_state);
  $form_state['input'] = $form_state['values'];
  $form_state['programmed'] = TRUE;
  // Programmed forms are always submitted.
  $form_state['submitted'] = TRUE;

  drupal_prepare_form($form_id, $form, $form_state);
  drupal_process_form($form_id, $form, $form_state);
}

/**
 * Retrieves the structured array that defines a given form.
 *
 * @param $form_id
 *   The unique string identifying the desired form. If a function
 *   with that name exists, it is called to build the form array.
 *   Modules that need to generate the same form (or very similar forms)
 *   using different $form_ids can implement hook_forms(), which maps
 *   different $form_id values to the proper form constructor function.
 * @param $form_state
 *   A keyed array containing the current state of the form.
 * @param ...
 *   Any additional arguments needed by the unique form constructor
 *   function. Generally, these are any arguments passed into the
 *   drupal_get_form() or drupal_form_submit() functions after the first
 *   argument. If a module implements hook_forms(), it can examine
 *   these additional arguments and conditionally return different
 *   builder functions as well.
 */
function drupal_retrieve_form($form_id, &$form_state) {
  $forms = &drupal_static(__FUNCTION__);

  // We save two copies of the incoming arguments: one for modules to use
  // when mapping form ids to constructor functions, and another to pass to
  // the constructor function itself.
  $args = $form_state['build_info']['args'];

  // We first check to see if there's a function named after the $form_id.
  // If there is, we simply pass the arguments on to it to get the form.
  if (!function_exists($form_id)) {
    // In cases where many form_ids need to share a central constructor function,
    // such as the node editing form, modules can implement hook_forms(). It
    // maps one or more form_ids to the correct constructor functions.
    //
    // We cache the results of that hook to save time, but that only works
    // for modules that know all their form_ids in advance. (A module that
    // adds a small 'rate this comment' form to each comment in a list
    // would need a unique form_id for each one, for example.)
    //
    // So, we call the hook if $forms isn't yet populated, OR if it doesn't
    // yet have an entry for the requested form_id.
    if (!isset($forms) || !isset($forms[$form_id])) {
      $forms = module_invoke_all('forms', $form_id, $args);
    }
    $form_definition = $forms[$form_id];
    if (isset($form_definition['callback arguments'])) {
      $args = array_merge($form_definition['callback arguments'], $args);
    }
    if (isset($form_definition['callback'])) {
      $callback = $form_definition['callback'];
    }
    // In case $form_state['wrapper_callback'] is not defined already, we also
    // allow hook_forms() to define one.
    if (!isset($form_state['wrapper_callback']) && isset($form_definition['wrapper_callback'])) {
      $form_state['wrapper_callback'] = $form_definition['wrapper_callback'];
    }
  }

  $form = array();
  // We need to pass $form_state by reference in order for forms to modify it,
  // since call_user_func_array() requires that referenced variables are passed
  // explicitly.
  $args = array_merge(array($form, &$form_state), $args);

  // When the passed $form_state (not using drupal_get_form()) defines a
  // 'wrapper_callback', then it requests to invoke a separate (wrapping) form
  // builder function to pre-populate the $form array with form elements, which
  // the actual form builder function ($callback) expects. This allows for
  // pre-populating a form with common elements for certain forms, such as
  // back/next/save buttons in multi-step form wizards.
  // @see drupal_build_form()
  if (isset($form_state['wrapper_callback']) && function_exists($form_state['wrapper_callback'])) {
    $form = call_user_func_array($form_state['wrapper_callback'], $args);
    // Put the prepopulated $form into $args.
    $args[0] = $form;
  }

  // If $callback was returned by a hook_forms() implementation, call it.
  // Otherwise, call the function named after the form id.
  $form = call_user_func_array(isset($callback) ? $callback : $form_id, $args);
  $form['#form_id'] = $form_id;

  return $form;
}

/**
 * Processes a form submission.
 *
 * This function is the heart of form API. The form gets built, validated and in
 * appropriate cases, submitted.
 *
 * @param $form_id
 *   The unique string identifying the current form.
 * @param $form
 *   An associative array containing the structure of the form.
 * @param $form_state
 *   A keyed array containing the current state of the form. This
 *   includes the current persistent storage data for the form, and
 *   any data passed along by earlier steps when displaying a
 *   multi-step form. Additional information, like the sanitized $_POST
 *   data, is also accumulated here.
 */
function drupal_process_form($form_id, &$form, &$form_state) {
  $form_state['values'] = array();

  // With $_GET, these forms are always submitted if requested.
  if ($form_state['method'] == 'get' && !empty($form_state['always_process'])) {
    if (!isset($form_state['input']['form_build_id'])) {
      $form_state['input']['form_build_id'] = $form['#build_id'];
    }
    if (!isset($form_state['input']['form_id'])) {
      $form_state['input']['form_id'] = $form_id;
    }
    if (!isset($form_state['input']['form_token']) && isset($form['#token'])) {
      $form_state['input']['form_token'] = drupal_get_token($form['#token']);
    }
  }

  // Build the form.
  $form = form_builder($form_id, $form, $form_state);

  // Only process the input if we have a correct form submission.
  if ($form_state['process_input']) {
    drupal_validate_form($form_id, $form, $form_state);

    // drupal_html_id() maintains a cache of element IDs it has seen,
    // so it can prevent duplicates. We want to be sure we reset that
    // cache when a form is processed, so scenarios that result in
    // the form being built behind the scenes and again for the
    // browser don't increment all the element IDs needlessly.
    drupal_static_reset('drupal_html_id');

    if ($form_state['submitted'] && !form_get_errors() && !$form_state['rebuild']) {
      // Execute form submit handlers.
      form_execute_handlers('submit', $form, $form_state);

      // We'll clear out the cached copies of the form and its stored data
      // here, as we've finished with them. The in-memory copies are still
      // here, though.
      if (variable_get('cache', CACHE_DISABLED) == CACHE_DISABLED && !empty($form_state['values']['form_build_id'])) {
        cache_clear_all('form_' . $form_state['values']['form_build_id'], 'cache_form');
        cache_clear_all('storage_' . $form_state['values']['form_build_id'], 'cache_form');
      }

      // If batches were set in the submit handlers, we process them now,
      // possibly ending execution. We make sure we do not react to the batch
      // that is already being processed (if a batch operation performs a
      // drupal_form_submit).
      if ($batch =& batch_get() && !isset($batch['current_set'])) {
        // Store $form_state information in the batch definition.
        // We need the full $form_state when either:
        // - Some submit handlers were saved to be called during batch
        //   processing. See form_execute_handlers().
        // - The form is multistep.
        // In other cases, we only need the information expected by
        // drupal_redirect_form().
        if ($batch['has_form_submits'] || !empty($form_state['rebuild']) || !empty($form_state['storage'])) {
          $batch['form_state'] = $form_state;
        }
        else {
          $batch['form_state'] = array_intersect_key($form_state, array_flip(array('programmed', 'rebuild', 'storage', 'no_redirect', 'redirect')));
        }

        $batch['progressive'] = !$form_state['programmed'];
        batch_process();

        // Execution continues only for programmatic forms.
        // For 'regular' forms, we get redirected to the batch processing
        // page. Form redirection will be handled in _batch_finished(),
        // after the batch is processed.
      }

      // Set a flag to indicate the the form has been processed and executed.
      $form_state['executed'] = TRUE;

      // Redirect the form based on values in $form_state.
      drupal_redirect_form($form_state);
    }
  }
}

/**
 * Prepares a structured form array by adding required elements,
 * executing any hook_form_alter functions, and optionally inserting
 * a validation token to prevent tampering.
 *
 * @param $form_id
 *   A unique string identifying the form for validation, submission,
 *   theming, and hook_form_alter functions.
 * @param $form
 *   An associative array containing the structure of the form.
 * @param $form_state
 *   A keyed array containing the current state of the form. Passed
 *   in here so that hook_form_alter() calls can use it, as well.
 */
function drupal_prepare_form($form_id, &$form, &$form_state) {
  global $user;

  $form['#type'] = 'form';
  $form_state['programmed'] = isset($form_state['programmed']) ? $form_state['programmed'] : FALSE;

  if (isset($form['#build_id'])) {
    $form['form_build_id'] = array(
      '#type' => 'hidden',
      '#value' => $form['#build_id'],
      '#id' => $form['#build_id'],
      '#name' => 'form_build_id',
    );
  }

  // Add a token, based on either #token or form_id, to any form displayed to
  // authenticated users. This ensures that any submitted form was actually
  // requested previously by the user and protects against cross site request
  // forgeries.
  // This does not apply to programmatically submitted forms. Furthermore, since
  // tokens are session-bound and forms displayed to anonymous users are very
  // likely cached, we cannot assign a token for them.
  // During installation, there is no $user yet.
  if (!empty($user->uid) && !$form_state['programmed']) {
    // Form constructors may explicitly set #token to FALSE when cross site
    // request forgery is irrelevant to the form, such as search forms.
    if (isset($form['#token']) && $form['#token'] === FALSE) {
      unset($form['#token']);
    }
    // Otherwise, generate a public token based on the form id.
    else {
      $form['#token'] = $form_id;
      $form['form_token'] = array(
        '#id' => drupal_html_id('edit-' . $form_id . '-form-token'),
        '#type' => 'token',
        '#default_value' => drupal_get_token($form['#token']),
      );
    }
  }

  if (isset($form_id)) {
    $form['form_id'] = array(
      '#type' => 'hidden',
      '#value' => $form_id,
      '#id' => drupal_html_id("edit-$form_id"),
    );
  }
  if (!isset($form['#id'])) {
    $form['#id'] = drupal_html_id($form_id);
  }

  $form += element_info('form');
  $form += array('#tree' => FALSE, '#parents' => array());

  if (!isset($form['#validate'])) {
    if (function_exists($form_id . '_validate')) {
      $form['#validate'] = array($form_id . '_validate');
    }
  }

  if (!isset($form['#submit'])) {
    if (function_exists($form_id . '_submit')) {
      // We set submit here so that it can be altered.
      $form['#submit'] = array($form_id . '_submit');
    }
  }

  // Invoke hook_form_FORM_ID_alter() implementations.
  drupal_alter('form_' . $form_id, $form, $form_state);

  // Invoke hook_form_alter() implementations.
  drupal_alter('form', $form, $form_state, $form_id);
}


/**
 * Validates user-submitted form data from the $form_state using
 * the validate functions defined in a structured form array.
 *
 * @param $form_id
 *   A unique string identifying the form for validation, submission,
 *   theming, and hook_form_alter functions.
 * @param $form
 *   An associative array containing the structure of the form, which is passed
 *   by reference. Form validation handlers are able to alter the form structure
 *   (like #process and #after_build callbacks during form building) in case of
 *   a validation error. If a validation handler alters the form structure, it
 *   is responsible for validating the values of changed form elements in
 *   $form_state['values'] to prevent form submit handlers from receiving
 *   unvalidated values.
 * @param $form_state
 *   A keyed array containing the current state of the form. The current
 *   user-submitted data is stored in $form_state['values'], though
 *   form validation functions are passed an explicit copy of the
 *   values for the sake of simplicity. Validation handlers can also
 *   $form_state to pass information on to submit handlers. For example:
 *     $form_state['data_for_submission'] = $data;
 *   This technique is useful when validation requires file parsing,
 *   web service requests, or other expensive requests that should
 *   not be repeated in the submission step.
 */
function drupal_validate_form($form_id, &$form, &$form_state) {
  $validated_forms = &drupal_static(__FUNCTION__, array());

  if (isset($validated_forms[$form_id]) && empty($form_state['must_validate'])) {
    return;
  }

  // If the session token was set by drupal_prepare_form(), ensure that it
  // matches the current user's session.
  if (isset($form['#token'])) {
    if (!drupal_valid_token($form_state['values']['form_token'], $form['#token'])) {
      // Setting this error will cause the form to fail validation.
      form_set_error('form_token', t('Validation error, please try again. If this error persists, please contact the site administrator.'));
    }
  }

  _form_validate($form, $form_state, $form_id);
  $validated_forms[$form_id] = TRUE;
}

/**
 * Redirects the user to a URL after a form has been processed.
 *
 * After a form was executed, the data in $form_state controls whether the form
 * is redirected. By default, we redirect to a new destination page. The path of
 * the destination page can be set in $form_state['redirect']. If that is not
 * set, the user is redirected to the current page to display a fresh,
 * unpopulated copy of the form.
 *
 * There are several triggers that may prevent a redirection though:
 * - If $form_state['redirect'] is FALSE, a form builder function or form
 *   validation/submit handler does not want a user to be redirected, which
 *   means that drupal_goto() is not invoked. For most forms, the redirection
 *   logic will be the same regardless of whether $form_state['redirect'] is
 *   undefined or FALSE. However, in case it was not defined and the current
 *   request contains a 'destination' query string, drupal_goto() will redirect
 *   to that given destination instead. Only setting $form_state['redirect'] to
 *   FALSE will prevent any redirection.
 * - If $form_state['no_redirect'] is TRUE, then the callback that originally
 *   built the form explicitly disallows any redirection, regardless of the
 *   redirection value in $form_state['redirect']. For example, ajax_get_form()
 *   defines $form_state['no_redirect'] when building a form in an AJAX
 *   callback to prevent any redirection. $form_state['no_redirect'] should NOT
 *   be altered by form builder functions or form validation/submit handlers.
 * - If $form_state['programmed'] is TRUE, the form submission was usually
 *   invoked via drupal_form_submit(), so any redirection would break the script
 *   that invoked drupal_form_submit().
 * - If $form_state['rebuild'] is TRUE, the form needs to be rebuilt without
 *   redirection.
 *
 * @param $form_state
 *   A keyed array containing the current state of the form.
 *
 * @see drupal_process_form()
 * @see drupal_build_form()
 */
function drupal_redirect_form($form_state) {
  // Skip redirection for form submissions invoked via drupal_form_submit().
  if (!empty($form_state['programmed'])) {
    return;
  }
  // Skip redirection if rebuild is activated.
  if (!empty($form_state['rebuild'])) {
    return;
  }
  // Skip redirection if it was explicitly disallowed.
  if (!empty($form_state['no_redirect'])) {
    return;
  }
  // Only invoke drupal_goto() if redirect value was not set to FALSE.
  if (!isset($form_state['redirect']) || $form_state['redirect'] !== FALSE) {
    if (isset($form_state['redirect'])) {
      if (is_array($form_state['redirect'])) {
        call_user_func_array('drupal_goto', $form_state['redirect']);
      }
      else {
        // This function can be called from the installer, which guarantees
        // that $redirect will always be a string, so catch that case here
        // and use the appropriate redirect function.
        $function = drupal_installation_attempted() ? 'install_goto' : 'drupal_goto';
        $function($form_state['redirect']);
      }
    }
    drupal_goto($_GET['q']);
  }
}

/**
 * Performs validation on form elements. First ensures required fields are
 * completed, #maxlength is not exceeded, and selected options were in the
 * list of options given to the user. Then calls user-defined validators.
 *
 * @param $elements
 *   An associative array containing the structure of the form.
 * @param $form_state
 *   A keyed array containing the current state of the form. The current
 *   user-submitted data is stored in $form_state['values'], though
 *   form validation functions are passed an explicit copy of the
 *   values for the sake of simplicity. Validation handlers can also
 *   $form_state to pass information on to submit handlers. For example:
 *     $form_state['data_for_submission'] = $data;
 *   This technique is useful when validation requires file parsing,
 *   web service requests, or other expensive requests that should
 *   not be repeated in the submission step.
 * @param $form_id
 *   A unique string identifying the form for validation, submission,
 *   theming, and hook_form_alter functions.
 */
function _form_validate(&$elements, &$form_state, $form_id = NULL) {
  // Also used in the installer, pre-database setup.
  $t = get_t();

  // Recurse through all children.
  foreach (element_children($elements) as $key) {
    if (isset($elements[$key]) && $elements[$key]) {
      _form_validate($elements[$key], $form_state);
    }
  }

  // Validate the current input.
  if (!isset($elements['#validated']) || !$elements['#validated']) {
    // The following errors are always shown.
    if (isset($elements['#needs_validation'])) {
      // Verify that the value is not longer than #maxlength.
      if (isset($elements['#maxlength']) && drupal_strlen($elements['#value']) > $elements['#maxlength']) {
        form_error($elements, $t('!name cannot be longer than %max characters but is currently %length characters long.', array('!name' => empty($elements['#title']) ? $elements['#parents'][0] : $elements['#title'], '%max' => $elements['#maxlength'], '%length' => drupal_strlen($elements['#value']))));
      }

      if (isset($elements['#options']) && isset($elements['#value'])) {
        if ($elements['#type'] == 'select') {
          $options = form_options_flatten($elements['#options']);
        }
        else {
          $options = $elements['#options'];
        }
        if (is_array($elements['#value'])) {
          $value = $elements['#type'] == 'checkboxes' ? array_keys(array_filter($elements['#value'])) : $elements['#value'];
          foreach ($value as $v) {
            if (!isset($options[$v])) {
              form_error($elements, $t('An illegal choice has been detected. Please contact the site administrator.'));
              watchdog('form', 'Illegal choice %choice in !name element.', array('%choice' => $v, '!name' => empty($elements['#title']) ? $elements['#parents'][0] : $elements['#title']), WATCHDOG_ERROR);
            }
          }
        }
        elseif (!isset($options[$elements['#value']])) {
          form_error($elements, $t('An illegal choice has been detected. Please contact the site administrator.'));
          watchdog('form', 'Illegal choice %choice in %name element.', array('%choice' => $elements['#value'], '%name' => empty($elements['#title']) ? $elements['#parents'][0] : $elements['#title']), WATCHDOG_ERROR);
        }
      }
    }

    // While this element is being validated, it may be desired that some calls
    // to form_set_error() be suppressed and not result in a form error, so
    // that a button that implements low-risk functionality (such as "Previous"
    // or "Add more") that doesn't require all user input to be valid can still
    // have its submit handlers triggered. The clicked button's
    // #limit_validation_errors property contains the information for which
    // errors are needed, and all other errors are to be suppressed. The
    // #limit_validation_errors property is ignored if the button doesn't also
    // define its own submit handlers, because it's too large a security risk to
    // have any invalid user input when executing form-level submit handlers.
    if (isset($form_state['clicked_button']['#limit_validation_errors']) && isset($form_state['clicked_button']['#submit'])) {
      form_set_error(NULL, '', $form_state['clicked_button']['#limit_validation_errors']);
    }
    else {
      // As an extra security measure, explicitly turn off error suppression.
      // Since this is also done at the end of this function, doing it here is
      // only to handle the rare edge case where a validate handler invokes form
      // processing of another form.
      drupal_static_reset('form_set_error:limit_validation_errors');
    }
    // Make sure a value is passed when the field is required.
    // A simple call to empty() will not cut it here as some fields, like
    // checkboxes, can return a valid value of '0'. Instead, check the
    // length if it's a string, and the item count if it's an array.
    // An unchecked checkbox has a #value of numeric 0, different than string
    // '0', which could be a valid value.
    if (isset($elements['#needs_validation']) && $elements['#required'] && (!count($elements['#value']) || (is_string($elements['#value']) && strlen(trim($elements['#value'])) == 0) || $elements['#value'] === 0)) {
      form_error($elements, $t('!name field is required.', array('!name' => $elements['#title'])));
    }

    // Call user-defined form level validators.
    if (isset($form_id)) {
      form_execute_handlers('validate', $elements, $form_state);
    }
    // Call any element-specific validators. These must act on the element
    // #value data.
    elseif (isset($elements['#element_validate'])) {
      foreach ($elements['#element_validate'] as $function) {
        $function($elements, $form_state, $form_state['complete form']);
      }
    }
    $elements['#validated'] = TRUE;
  }

  // Done validating this element, so turn off error suppression.
  // _form_validate() turns it on again when starting on the next element, if
  // it's still appropriate to do so.
  drupal_static_reset('form_set_error:limit_validation_errors');
}

/**
 * A helper function used to execute custom validation and submission
 * handlers for a given form. Button-specific handlers are checked
 * first. If none exist, the function falls back to form-level handlers.
 *
 * @param $type
 *   The type of handler to execute. 'validate' or 'submit' are the
 *   defaults used by Form API.
 * @param $form
 *   An associative array containing the structure of the form.
 * @param $form_state
 *   A keyed array containing the current state of the form. If the user
 *   submitted the form by clicking a button with custom handler functions
 *   defined, those handlers will be stored here.
 */
function form_execute_handlers($type, &$form, &$form_state) {
  $return = FALSE;
  // If there was a button pressed, use its handlers.
  if (isset($form_state[$type . '_handlers'])) {
    $handlers = $form_state[$type . '_handlers'];
  }
  // Otherwise, check for a form-level handler.
  elseif (isset($form['#' . $type])) {
    $handlers = $form['#' . $type];
  }
  else {
    $handlers = array();
  }

  foreach ($handlers as $function) {
    // Check if a previous _submit handler has set a batch, but make sure we
    // do not react to a batch that is already being processed (for instance
    // if a batch operation performs a drupal_form_submit()).
    if ($type == 'submit' && ($batch =& batch_get()) && !isset($batch['id'])) {
      // Some previous submit handler has set a batch. To ensure correct
      // execution order, store the call in a special 'control' batch set.
      // See _batch_next_set().
      $batch['sets'][] = array('form_submit' => $function);
      $batch['has_form_submits'] = TRUE;
    }
    else {
      $function($form, $form_state);
    }
    $return = TRUE;
  }
  return $return;
}

/**
 * Files an error against a form element.
 *
 * @param $name
 *   The name of the form element. If the #parents property of your form
 *   element is array('foo', 'bar', 'baz') then you may set an error on 'foo'
 *   or 'foo][bar][baz'. Setting an error on 'foo' sets an error for every
 *   element where the #parents array starts with 'foo'.
 * @param $message
 *   The error message to present to the user.
 * @param $limit_validation_errors
 *   Internal use only. The #limit_validation_errors property of the clicked
 *   button if it exists. Multistep forms not wanting to validate the whole form
 *   can set the #limit_validation_errors property on buttons to avoid
 *   validation errors of some elements preventing the button's submit handlers
 *   from running. For example, pressing the "Previous" button should not fire
 *   validation errors just because the current step has invalid values. AJAX is
 *   another typical example.
 *   If this property is set on the clicked button, the button must also define
 *   its #submit property and those handlers will be executed even if there is
 *   invalid input, so extreme care should be taken with respect to what is
 *   performed by them. This is typically not a problem with buttons like
 *   "Previous" or "Add more" that do not invoke persistent storage of the
 *   submitted form values.
 *   Do not use the #limit_validation_errors property on buttons that trigger
 *   saving of form values to the database.
 *   The #limit_validation_errors property is a list of "sections" within
 *   $form_state['values'] that must contain valid values. Each "section" is an
 *   array with the ordered set of keys needed to reach that part of
 *   $form_state['values'] (i.e., the #parents property of the element).
 *   For example:
 *   @code
 *     $form['actions']['previous']['#limit_validation_errors'] = array(
 *       array('step1'),
 *       array('foo', 'bar'),
 *     );
 *   @endcode
 *   This will require $form_state['values']['step1'] and everything within it
 *   (for example, $form_state['values']['step1']['choice']) to be valid, so
 *   calls to form_set_error('step1', $message) or
 *   form_set_error('step1][choice', $message) will prevent the submit handlers
 *   from running, and result in the error message being displayed to the user.
 *   However, calls to form_set_error('step2', $message) and
 *   form_set_error('step2][groupX][choiceY', $message) will be suppressed,
 *   resulting in the message not being displayed to the user, and the submit
 *   handlers will run despite $form_state['values']['step2'] and
 *   $form_state['values']['step2']['groupX']['choiceY'] containing invalid
 *   values. Errors for an invalid $form_state['values']['foo'] will be
 *   suppressed, but errors for invalid values for
 *   $form_state['values']['foo']['bar'] and everything within it will be
 *   recorded. If the button doesn't need any user input to be valid, then the
 *   #limit_validation_errors can be set to an empty array, in which case, all
 *   calls to form_set_error() will be suppressed.
 *   Partial form validation is implemented by suppressing errors rather than by
 *   skipping the input processing and validation steps entirely, because some
 *   forms have button-level submit handlers that call Drupal API functions that
 *   assume that certain data exists within $form_state['values'], and while not
 *   doing anything with that data that requires it to be valid, PHP errors
 *   would be triggered if the input processing and validation steps were fully
 *   skipped. @see http://drupal.org/node/370537.
 *
 * @return
 *   Return value is for internal use only. To get a list of errors, use
 *   form_get_errors() or form_get_error().
 */
function form_set_error($name = NULL, $message = '', $limit_validation_errors = NULL) {
  $form = &drupal_static(__FUNCTION__, array());
  $sections = &drupal_static(__FUNCTION__ . ':limit_validation_errors');
  if (isset($limit_validation_errors)) {
    $sections = $limit_validation_errors;
  }

  if (isset($name) && !isset($form[$name])) {
    $record = TRUE;
    if (isset($sections)) {
      // #limit_validation_errors is an array of "sections" within which user
      // input must be valid. If the element is within one of these sections,
      // the error must be recorded. Otherwise, it can be suppressed.
      // #limit_validation_errors can be an empty array, in which case all
      // errors are suppressed. For example, a "Previous" button might want its
      // submit action to be triggered even if none of the submitted values are
      // valid.
      $record = FALSE;
      foreach ($sections as $section) {
        // Exploding by '][' reconstructs the element's #parents. If the
        // reconstructed #parents begin with the same keys as the specified
        // section, then the element's values are within the part of
        // $form_state['values'] that the clicked button requires to be valid,
        // so errors for this element must be recorded.
        if (array_slice(explode('][', $name), 0, count($section)) === $section) {
          $record = TRUE;
          break;
        }
      }
    }
    if ($record) {
      $form[$name] = $message;
      if ($message) {
        drupal_set_message($message, 'error');
      }
    }
  }

  return $form;
}

/**
 * Clear all errors against all form elements made by form_set_error().
 */
function form_clear_error() {
  drupal_static_reset('form_set_error');
}

/**
 * Return an associative array of all errors.
 */
function form_get_errors() {
  $form = form_set_error();
  if (!empty($form)) {
    return $form;
  }
}

/**
 * Return the error message filed against the form with the specified name.
 */
function form_get_error($element) {
  $form = form_set_error();
  $key = $element['#parents'][0];
  if (isset($form[$key])) {
    return $form[$key];
  }
  $key = implode('][', $element['#parents']);
  if (isset($form[$key])) {
    return $form[$key];
  }
}

/**
 * Flag an element as having an error.
 */
function form_error(&$element, $message = '') {
  form_set_error(implode('][', $element['#parents']), $message);
}

/**
 * Walk through the structured form array, adding any required
 * properties to each element and mapping the incoming input
 * data to the proper elements. Also, execute any #process handlers
 * attached to a specific element.
 *
 * @param $form_id
 *   A unique string identifying the form for validation, submission,
 *   theming, and hook_form_alter functions.
 * @param $element
 *   An associative array containing the structure of the current element.
 * @param $form_state
 *   A keyed array containing the current state of the form. In this
 *   context, it is used to accumulate information about which button
 *   was clicked when the form was submitted, as well as the sanitized
 *   $_POST data.
 */
function form_builder($form_id, $element, &$form_state) {
  // Initialize as unprocessed.
  $element['#processed'] = FALSE;

  // Use element defaults.
  if (isset($element['#type']) && ($info = element_info($element['#type']))) {
    // Overlay $info onto $element, retaining preexisting keys in $element.
    $element += $info;
    $element['#defaults_loaded'] = TRUE;
  }
  // Assign basic defaults common for all form elements.
  $element += array(
    '#required' => FALSE,
    '#attributes' => array(),
    '#title_display' => 'before',
  );

  // Special handling if we're on the top level form element.
  if (isset($element['#type']) && $element['#type'] == 'form') {
    if (!empty($element['#https']) && variable_get('https', FALSE) &&
        !url_is_external($element['#action'])) {
      global $base_root;

      // Not an external URL so ensure that it is secure.
      $element['#action'] = str_replace('http://', 'https://', $base_root) . $element['#action'];
    }

    // Store a complete copy of the form in form_state prior to building the form.
    $form_state['complete form'] = $element;
    // Set a flag if we have a correct form submission. This is always TRUE for
    // programmed forms coming from drupal_form_submit(), or if the form_id coming
    // from the POST data is set and matches the current form_id.
    if ($form_state['programmed'] || (!empty($form_state['input']) && (isset($form_state['input']['form_id']) && ($form_state['input']['form_id'] == $form_id)))) {
      $form_state['process_input'] = TRUE;
    }
    else {
      $form_state['process_input'] = FALSE;
    }
  }

  if (!isset($element['#id'])) {
    $element['#id'] = drupal_html_id('edit-' . implode('-', $element['#parents']));
  }
  // Handle input elements.
  if (!empty($element['#input'])) {
    _form_builder_handle_input_element($form_id, $element, $form_state);
  }
  // Allow for elements to expand to multiple elements, e.g., radios,
  // checkboxes and files.
  if (isset($element['#process']) && !$element['#processed']) {
    foreach ($element['#process'] as $process) {
      $element = $process($element, $form_state, $form_state['complete form']);
    }
    $element['#processed'] = TRUE;
  }

  // We start off assuming all form elements are in the correct order.
  $element['#sorted'] = TRUE;

  // Recurse through all child elements.
  $count = 0;
  foreach (element_children($element) as $key) {
    // Don't squash an existing tree value.
    if (!isset($element[$key]['#tree'])) {
      $element[$key]['#tree'] = $element['#tree'];
    }

    // Deny access to child elements if parent is denied.
    if (isset($element['#access']) && !$element['#access']) {
      $element[$key]['#access'] = FALSE;
    }

    // Don't squash existing parents value.
    if (!isset($element[$key]['#parents'])) {
      // Check to see if a tree of child elements is present. If so,
      // continue down the tree if required.
      $element[$key]['#parents'] = $element[$key]['#tree'] && $element['#tree'] ? array_merge($element['#parents'], array($key)) : array($key);
    }
    // Ensure #array_parents follows the actual form structure.
    $array_parents = isset($element['#array_parents']) ? $element['#array_parents'] : array();
    $array_parents[] = $key;
    $element[$key]['#array_parents'] = $array_parents;

    // Assign a decimal placeholder weight to preserve original array order.
    if (!isset($element[$key]['#weight'])) {
      $element[$key]['#weight'] = $count/1000;
    }
    else {
      // If one of the child elements has a weight then we will need to sort
      // later.
      unset($element['#sorted']);
    }
    $element[$key] = form_builder($form_id, $element[$key], $form_state);
    $count++;
  }

  // The #after_build flag allows any piece of a form to be altered
  // after normal input parsing has been completed.
  if (isset($element['#after_build']) && !isset($element['#after_build_done'])) {
    foreach ($element['#after_build'] as $function) {
      $element = $function($element, $form_state);
    }
    $element['#after_build_done'] = TRUE;
  }

  // Now that we've processed everything, we can go back to handle the funky
  // Internet Explorer button-click scenario.
  _form_builder_ie_cleanup($element, $form_state);

  // If there is a file element, we need to flip a flag so later the
  // form encoding can be set.
  if (isset($element['#type']) && $element['#type'] == 'file') {
    $form_state['has_file_element'] = TRUE;
  }

  if (isset($element['#type']) && $element['#type'] == 'form') {
    // We are on the top form.
    // If there is a file element, we set the form encoding.
    if (isset($form_state['has_file_element'])) {
      $element['#attributes']['enctype'] = 'multipart/form-data';
    }
    // Update the copy of the complete form for usage in validation handlers.
    $form_state['complete form'] = $element;
  }
  return $element;
}

/**
 * Populate the #value and #name properties of input elements so they
 * can be processed and rendered.
 */
function _form_builder_handle_input_element($form_id, &$element, &$form_state) {
  if (!isset($element['#name'])) {
    $name = array_shift($element['#parents']);
    $element['#name'] = $name;
    if ($element['#type'] == 'file') {
      // To make it easier to handle $_FILES in file.inc, we place all
      // file fields in the 'files' array. Also, we do not support
      // nested file names.
      $element['#name'] = 'files[' . $element['#name'] . ']';
    }
    elseif (count($element['#parents'])) {
      $element['#name'] .= '[' . implode('][', $element['#parents']) . ']';
    }
    array_unshift($element['#parents'], $name);
  }

  if (!empty($element['#disabled'])) {
    $element['#attributes']['disabled'] = 'disabled';
  }

  // Set the element's #value property.
  if (!isset($element['#value']) && !array_key_exists('#value', $element)) {
    $value_callback = !empty($element['#value_callback']) ? $element['#value_callback'] : 'form_type_' . $element['#type'] . '_value';

    if ($form_state['programmed'] || ($form_state['process_input'] && (!isset($element['#access']) || $element['#access']))) {
      // Get the input for the current element. NULL values in the input need to
      // be explicitly distinguished from missing input. (see below)
      $input = $form_state['input'];
      $input_exists = TRUE;
      foreach ($element['#parents'] as $parent) {
        if (is_array($input) && array_key_exists($parent, $input)) {
          $input = $input[$parent];
        }
        else {
          $input = NULL;
          $input_exists = FALSE;
          break;
        }
      }
      // For browser-submitted forms, the submitted values do not contain values
      // for certain elements (empty multiple select, unchecked checkbox).
      // During initial form processing, we add explicit NULL values for such
      // elements in $form_state['input']. When rebuilding the form, we can
      // distinguish elements having NULL input from elements that were not part
      // of the initially submitted form and can therefore use default values
      // for the latter, if required. Programmatically submitted forms can
      // submit explicit NULL values when calling drupal_form_submit(), so we do
      // not modify $form_state['input'] for them.
      if (!$input_exists && !$form_state['rebuild'] && !$form_state['programmed']) {
        // We leverage the internal logic of form_set_value() to change the
        // input values by passing $form_state['input'] instead of the usual
        // $form_state['values']. In effect, this adds the necessary parent keys
        // to $form_state['input'] and sets the element's input value to NULL.
        _form_set_value($form_state['input'], $element, $element['#parents'], NULL);
        $input_exists = TRUE;
      }
      // If we have input for the current element, assign it to the #value
      // property, optionally filtered through $value_callback.
      if ($input_exists) {
        if (function_exists($value_callback)) {
          $element['#value'] = $value_callback($element, $input, $form_state);
        }
        if (!isset($element['#value']) && isset($input)) {
          $element['#value'] = $input;
        }
      }
      // Mark all posted values for validation.
      if (isset($element['#value']) || (!empty($element['#required']))) {
        $element['#needs_validation'] = TRUE;
      }
    }
    // Load defaults.
    if (!isset($element['#value'])) {
      // Call #type_value without a second argument to request default_value handling.
      if (function_exists($value_callback)) {
        $element['#value'] = $value_callback($element, FALSE, $form_state);
      }
      // Final catch. If we haven't set a value yet, use the explicit default value.
      // Avoid image buttons (which come with garbage value), so we only get value
      // for the button actually clicked.
      if (!isset($element['#value']) && empty($element['#has_garbage_value'])) {
        $element['#value'] = isset($element['#default_value']) ? $element['#default_value'] : '';
      }
    }
  }

  // Determine which button (if any) was clicked to submit the form.
  // We compare the incoming values with the buttons defined in the form,
  // and flag the one that matches. We have to do some funky tricks to
  // deal with Internet Explorer's handling of single-button forms, though.
  if (!empty($form_state['input']) && isset($element['#executes_submit_callback'])) {
    // First, accumulate a collection of buttons, divided into two bins:
    // those that execute full submit callbacks and those that only validate.
    $button_type = $element['#executes_submit_callback'] ? 'submit' : 'button';
    $form_state['buttons'][$button_type][] = $element;

    if (_form_button_was_clicked($element, $form_state)) {
      $form_state['submitted'] = $form_state['submitted'] || $element['#executes_submit_callback'];

      // In most cases, we want to use form_set_value() to manipulate
      // the global variables. In this special case, we want to make sure that
      // the value of this element is listed in $form_variables under 'op'.
      $form_state['values'][$element['#name']] = $element['#value'];
      $form_state['clicked_button'] = $element;

      if (isset($element['#validate'])) {
        $form_state['validate_handlers'] = $element['#validate'];
      }
      if (isset($element['#submit'])) {
        $form_state['submit_handlers'] = $element['#submit'];
      }
    }
  }
  form_set_value($element, $element['#value'], $form_state);
}

/**
 * Helper function to handle the sometimes-convoluted logic of button
 * click detection.
 *
 * In Internet Explorer, if ONLY one submit button is present, AND the
 * enter key is used to submit the form, no form value is sent for it
 * and we'll never detect a match. That special case is handled by
 * _form_builder_ie_cleanup().
 */
function _form_button_was_clicked($form, &$form_state) {
  // First detect normal 'vanilla' button clicks. Traditionally, all
  // standard buttons on a form share the same name (usually 'op'),
  // and the specific return value is used to determine which was
  // clicked. This ONLY works as long as $form['#name'] puts the
  // value at the top level of the tree of $_POST data.
  if (isset($form_state['input'][$form['#name']]) && $form_state['input'][$form['#name']] == $form['#value']) {
    return TRUE;
  }
  // When image buttons are clicked, browsers do NOT pass the form element
  // value in $_POST. Instead they pass an integer representing the
  // coordinates of the click on the button image. This means that image
  // buttons MUST have unique $form['#name'] values, but the details of
  // their $_POST data should be ignored.
  elseif (!empty($form['#has_garbage_value']) && isset($form['#value']) && $form['#value'] !== '') {
    return TRUE;
  }
  return FALSE;
}

/**
 * In IE, if only one submit button is present, AND the enter key is
 * used to submit the form, no form value is sent for it and our normal
 * button detection code will never detect a match. We call this
 * function after all other button-detection is complete to check
 * for the proper conditions, and treat the single button on the form
 * as 'clicked' if they are met.
 */
function _form_builder_ie_cleanup($form, &$form_state) {
  // Quick check to make sure we're always looking at the full form
  // and not a sub-element.
  if (!empty($form['#type']) && $form['#type'] == 'form') {
    // If we haven't recognized a submission yet, and there's a single
    // submit button, we know that we've hit the right conditions. Grab
    // the first one and treat it as the clicked button.
    if (empty($form_state['submitted']) && !empty($form_state['buttons']['submit']) && empty($form_state['buttons']['button'])) {
      $button = $form_state['buttons']['submit'][0];

      // Set up all the $form_state information that would have been
      // populated had the button been recognized earlier.
      $form_state['submitted'] = TRUE;
      $form_state['submit_handlers'] = empty($button['#submit']) ? NULL : $button['#submit'];
      $form_state['validate_handlers'] = empty($button['#validate']) ? NULL : $button['#validate'];
      $form_state['values'][$button['#name']] = $button['#value'];
      $form_state['clicked_button'] = $button;
    }
  }
}

/**
 * Removes internal Form API elements and buttons from submitted form values.
 *
 * This function can be used when a module wants to store all submitted form
 * values, for example, by serializing them into a single database column. In
 * such cases, all internal Form API values and all form button elements should
 * not be contained, and this function allows to remove them before the module
 * proceeds to storage. Next to button elements, the following internal values
 * are removed:
 * - form_id
 * - form_token
 * - form_build_id
 * - op
 *
 * @param &$form_state
 *   A keyed array containing the current state of the form, including
 *   submitted form values; altered by reference.
 */
function form_state_values_clean(&$form_state) {
  // Remove internal Form API values.
  unset($form_state['values']['form_id'], $form_state['values']['form_token'], $form_state['values']['form_build_id'], $form_state['values']['op']);

  // Remove button values.
  // form_builder() collects all button elements in a form, keyed by button
  // type. We remove the button value separately for each button element.
  foreach ($form_state['buttons'] as $button_type => $buttons) {
    foreach ($buttons as $button) {
      // Remove this button's value from the submitted form values by finding
      // the value corresponding to this button.
      // We iterate over the #parents of this button and move a reference to
      // each parent in $form_state['values']. For example, if #parents is:
      //   array('foo', 'bar', 'baz')
      // then the corresponding $form_state['values'] part will look like this:
      // array(
      //   'foo' => array(
      //     'bar' => array(
      //       'baz' => 'button_value',
      //     ),
      //   ),
      // )
      // We start by (re)moving 'baz' to $last_parent, so we are able unset it
      // at the end of the iteration. Initially, $values will contain a
      // reference to $form_state['values'], but in the iteration we move the
      // reference to $form_state['values']['foo'], and finally to
      // $form_state['values']['foo']['bar'], which is the level where we can
      // unset 'baz' (that is stored in $last_parent).
      $parents = $button['#parents'];
      $values = &$form_state['values'];
      $last_parent = array_pop($parents);
      foreach ($parents as $parent) {
        $values = &$values[$parent];
      }
      unset($values[$last_parent]);
    }
  }
}

/**
 * Helper function to determine the value for an image button form element.
 *
 * @param $form
 *   The form element whose value is being populated.
 * @param $input
 *   The incoming input to populate the form element. If this is FALSE,
 *   the element's default value should be returned.
 * @param $form_state
 *   A keyed array containing the current state of the form.
 * @return
 *   The data that will appear in the $form_state['values'] collection
 *   for this element. Return nothing to use the default.
 */
function form_type_image_button_value($form, $input, $form_state) {
  if ($input !== FALSE) {
    if (!empty($input)) {
      // If we're dealing with Mozilla or Opera, we're lucky. It will
      // return a proper value, and we can get on with things.
      return $form['#return_value'];
    }
    else {
      // Unfortunately, in IE we never get back a proper value for THIS
      // form element. Instead, we get back two split values: one for the
      // X and one for the Y coordinates on which the user clicked the
      // button. We'll find this element in the #post data, and search
      // in the same spot for its name, with '_x'.
      $input = $form_state['input'];
      foreach (explode('[', $form['#name']) as $element_name) {
        // chop off the ] that may exist.
        if (substr($element_name, -1) == ']') {
          $element_name = substr($element_name, 0, -1);
        }

        if (!isset($input[$element_name])) {
          if (isset($input[$element_name . '_x'])) {
            return $form['#return_value'];
          }
          return NULL;
        }
        $input = $input[$element_name];
      }
      return $form['#return_value'];
    }
  }
}

/**
 * Helper function to determine the value for a checkbox form element.
 *
 * @param $form
 *   The form element whose value is being populated.
*  @param $input
 *   The incoming input to populate the form element. If this is FALSE,
 *   the element's default value should be returned.
 * @return
 *   The data that will appear in the $element_state['values'] collection
 *   for this element. Return nothing to use the default.
 */
function form_type_checkbox_value($element, $input = FALSE) {
  if ($input !== FALSE) {
    if (empty($element['#disabled'])) {
      // Successful (checked) checkboxes are present with a value (possibly '0').
      // http://www.w3.org/TR/html401/interact/forms.html#successful-controls
      // For an unchecked checkbox, we return numeric 0, so we can explicitly
      // test for a value different than string '0'.
      return isset($input) ? $element['#return_value'] : 0;
    }
    else {
      // Disabled form controls are not submitted by the browser. Ignore any
      // submitted value and always return default.
      return $element['#default_value'];
    }
  }
}

/**
 * Helper function to determine the value for a checkboxes form element.
 *
 * @param $element
 *   The form element whose value is being populated.
 * @param $input
 *   The incoming input to populate the form element. If this is FALSE,
 *   the element's default value should be returned.
 * @return
 *   The data that will appear in the $element_state['values'] collection
 *   for this element. Return nothing to use the default.
 */
function form_type_checkboxes_value($element, $input = FALSE) {
  if ($input === FALSE) {
    $value = array();
    $element += array('#default_value' => array());
    foreach ($element['#default_value'] as $key) {
      $value[$key] = 1;
    }
    return $value;
  }
  elseif (!isset($input)) {
    return array();
  }
}

/**
 * Helper function to determine the value for a password_confirm form
 * element.
 *
 * @param $element
 *   The form element whose value is being populated.
 * @param $input
 *   The incoming input to populate the form element. If this is FALSE,
 *   the element's default value should be returned.
 * @return
 *   The data that will appear in the $element_state['values'] collection
 *   for this element. Return nothing to use the default.
 */
function form_type_password_confirm_value($element, $input = FALSE) {
  if ($input === FALSE) {
    $element += array('#default_value' => array());
    return $element['#default_value'] + array('pass1' => '', 'pass2' => '');
  }
}

/**
 * Helper function to determine the value for a select form element.
 *
 * @param $element
 *   The form element whose value is being populated.
 * @param $input
 *   The incoming input to populate the form element. If this is FALSE,
 *   the element's default value should be returned.
 * @return
 *   The data that will appear in the $element_state['values'] collection
 *   for this element. Return nothing to use the default.
 */
function form_type_select_value($element, $input = FALSE) {
  if ($input !== FALSE) {
    if (isset($element['#multiple']) && $element['#multiple']) {
      return (is_array($input)) ? drupal_map_assoc($input) : array();
    }
    else {
      return $input;
    }
  }
}

/**
 * Helper function to determine the value for a textfield form element.
 *
 * @param $element
 *   The form element whose value is being populated.
 * @param $input
 *   The incoming input to populate the form element. If this is FALSE,
 *   the element's default value should be returned.
 * @return
 *   The data that will appear in the $element_state['values'] collection
 *   for this element. Return nothing to use the default.
 */
function form_type_textfield_value($element, $input = FALSE) {
  if ($input !== FALSE) {
    // Equate $input to the form value to ensure it's marked for
    // validation.
    return str_replace(array("\r", "\n"), '', $input);
  }
}

/**
 * Helper function to determine the value for form's token value.
 *
 * @param $element
 *   The form element whose value is being populated.
 * @param $input
 *   The incoming input to populate the form element. If this is FALSE,
 *   the element's default value should be returned.
 * @return
 *   The data that will appear in the $element_state['values'] collection
 *   for this element. Return nothing to use the default.
 */
function form_type_token_value($element, $input = FALSE) {
  if ($input !== FALSE) {
    return (string)$input;
  }
}

/**
 * Change submitted form values during form validation.
 *
 * Use this function to change the submitted value of a form element in a form
 * validation function, so that the changed value persists in $form_state
 * through to the submission handlers.
 *
 * Note that form validation functions are specified in the '#validate'
 * component of the form array (the value of $form['#validate'] is an array of
 * validation function names). If the form does not originate in your module,
 * you can implement hook_form_FORM_ID_alter() to add a validation function
 * to $form['#validate'].
 *
 * @param $element
 *   The form element that should have its value updated; in most cases you can
 *   just pass in the element from the $form array, although the only component
 *   that is actually used is '#parents'. If constructing yourself, set
 *   $element['#parents'] to be an array giving the path through the form
 *   array's keys to the element whose value you want to update. For instance,
 *   if you want to update the value of $form['elem1']['elem2'], which should be
 *   stored in $form_state['values']['elem1']['elem2'], you would set
 *   $element['#parents'] = array('elem1','elem2').
 * @param $value
 *   The new value for the form element.
 * @param $form_state
 *   Form state array where the value change should be recorded.
 */
function form_set_value($element, $value, &$form_state) {
  _form_set_value($form_state['values'], $element, $element['#parents'], $value);
}

/**
 * Helper function for form_set_value() and _form_builder_handle_input_element().
 *
 * We iterate over $parents and create nested arrays for them in $form_values if
 * needed. Then we insert the value into the last parent key.
 */
function _form_set_value(&$form_values, $element, $parents, $value) {
  $parent = array_shift($parents);
  if (empty($parents)) {
    $form_values[$parent] = $value;
  }
  else {
    if (!isset($form_values[$parent])) {
      $form_values[$parent] = array();
    }
    _form_set_value($form_values[$parent], $element, $parents, $value);
  }
}

function form_options_flatten($array) {
  // Always reset static var when first entering the recursion.
  drupal_static_reset('_form_options_flatten');
  return _form_options_flatten($array);
}

function _form_options_flatten($array) {
  $return = &drupal_static(__FUNCTION__);

  foreach ($array as $key => $value) {
    if (is_object($value)) {
      _form_options_flatten($value->option);
    }
    elseif (is_array($value)) {
      _form_options_flatten($value);
    }
    else {
      $return[$key] = 1;
    }
  }

  return $return;
}

/**
 * Theme select form element.
 *
 * @param $variables
 *   An associative array containing:
 *   - element: An associative array containing the properties of the element.
 *     Properties used: #title, #value, #options, #description, #extra,
 *     #multiple, #required, #name, #attributes, #size.
 *
 * @return
 *   A themed HTML string representing the form element.
 *
 * @ingroup themeable
 *
 * It is possible to group options together; to do this, change the format of
 * $options to an associative array in which the keys are group labels, and the
 * values are associative arrays in the normal $options format.
 */
function theme_select($variables) {
  $element = $variables['element'];
  $size = $element['#size'] ? ' size="' . $element['#size'] . '"' : '';
  _form_set_class($element, array('form-select'));
  $multiple = $element['#multiple'];
  return '<select name="' . $element['#name'] . '' . ($multiple ? '[]' : '') . '"' . ($multiple ? ' multiple="multiple" ' : '') . drupal_attributes($element['#attributes']) . ' id="' . $element['#id'] . '" ' . $size . '>' . form_select_options($element) . '</select>';
}

/**
 * Convert a select form element's options array into an HTML.
 *
 * @param $element
 *   An associative array containing the properties of the element.
 * @param $choices
 *   Mixed: Either an associative array of items to list as choices, or an
 *   object with an 'option' member that is an associative array. This
 *   parameter is only used internally and should not be passed.
 * @return
 *   An HTML string of options for the select form element.
 */
function form_select_options($element, $choices = NULL) {
  if (!isset($choices)) {
    $choices = $element['#options'];
  }
  // array_key_exists() accommodates the rare event where $element['#value'] is NULL.
  // isset() fails in this situation.
  $value_valid = isset($element['#value']) || array_key_exists('#value', $element);
  $value_is_array = is_array($element['#value']);
  $options = '';
  foreach ($choices as $key => $choice) {
    if (is_array($choice)) {
      $options .= '<optgroup label="' . $key . '">';
      $options .= form_select_options($element, $choice);
      $options .= '</optgroup>';
    }
    elseif (is_object($choice)) {
      $options .= form_select_options($element, $choice->option);
    }
    else {
      $key = (string)$key;
      if ($value_valid && (!$value_is_array && (string)$element['#value'] === $key || ($value_is_array && in_array($key, $element['#value'])))) {
        $selected = ' selected="selected"';
      }
      else {
        $selected = '';
      }
      $options .= '<option value="' . check_plain($key) . '"' . $selected . '>' . check_plain($choice) . '</option>';
    }
  }
  return $options;
}

/**
 * Traverses a select element's #option array looking for any values
 * that hold the given key. Returns an array of indexes that match.
 *
 * This function is useful if you need to modify the options that are
 * already in a form element; for example, to remove choices which are
 * not valid because of additional filters imposed by another module.
 * One example might be altering the choices in a taxonomy selector.
 * To correctly handle the case of a multiple hierarchy taxonomy,
 * #options arrays can now hold an array of objects, instead of a
 * direct mapping of keys to labels, so that multiple choices in the
 * selector can have the same key (and label). This makes it difficult
 * to manipulate directly, which is why this helper function exists.
 *
 * This function does not support optgroups (when the elements of the
 * #options array are themselves arrays), and will return FALSE if
 * arrays are found. The caller must either flatten/restore or
 * manually do their manipulations in this case, since returning the
 * index is not sufficient, and supporting this would make the
 * "helper" too complicated and cumbersome to be of any help.
 *
 * As usual with functions that can return array() or FALSE, do not
 * forget to use === and !== if needed.
 *
 * @param $element
 *   The select element to search.
 * @param $key
 *   The key to look for.
 * @return
 *   An array of indexes that match the given $key. Array will be
 *   empty if no elements were found. FALSE if optgroups were found.
 */
function form_get_options($element, $key) {
  $keys = array();
  foreach ($element['#options'] as $index => $choice) {
    if (is_array($choice)) {
      return FALSE;
    }
    elseif (is_object($choice)) {
      if (isset($choice->option[$key])) {
        $keys[] = $index;
      }
    }
    elseif ($index == $key) {
      $keys[] = $index;
    }
  }
  return $keys;
}

/**
 * Theme a fieldset form element.
 *
 * @param $variables
 *   An associative array containing:
 *   - element: An associative array containing the properties of the element.
 *     Properties used: #attributes, #children, #collapsed, #collapsible,
 *     #description, #id, #title, #value.
 *
 * @return
 *   A themed HTML string representing the group of items.
 *
 * @ingroup themeable
 */
function theme_fieldset($variables) {
  $element = $variables['element'];

  $output = '<fieldset' . drupal_attributes($element['#attributes']) . '>';
  if (!empty($element['#title'])) {
    // Always wrap fieldset legends in a SPAN for CSS positioning.
    $output .= '<legend><span class="fieldset-legend">' . $element['#title'] . '</span></legend>';
  }
  $output .= '<div class="fieldset-wrapper">';
  if (!empty($element['#description'])) {
    $output .= '<div class="fieldset-description">' . $element['#description'] . '</div>';
  }
  $output .= $element['#children'];
  if (isset($element['#value'])) {
    $output .= $element['#value'];
  }
  $output .= '</div>';
  $output .= "</fieldset>\n";
  return $output;
}

/**
 * Theme a radio button form element.
 *
 * @param $variables
 *   An associative array containing:
 *   - element: An associative array containing the properties of the element.
 *     Properties used: #required, #return_value, #value, #attributes, #title,
 *     #description
 *
 * @return
 *   A themed HTML string representing the form item group.
 *
 * @ingroup themeable
 */
function theme_radio($variables) {
  $element = $variables['element'];
  _form_set_class($element, array('form-radio'));
  $output = '<input type="radio" ';
  $output .= 'id="' . $element['#id'] . '" ';
  $output .= 'name="' . $element['#name'] . '" ';
  $output .= 'value="' . $element['#return_value'] . '" ';
  $output .= (check_plain($element['#value']) == $element['#return_value']) ? ' checked="checked" ' : ' ';
  $output .= drupal_attributes($element['#attributes']) . ' />';

  return $output;
}

/**
 * Theme a set of radio button form elements.
 *
 * @param $variables
 *   An associative array containing:
 *   - element: An associative array containing the properties of the element.
 *     Properties used: #title, #value, #options, #description, #required,
 *     #attributes, #children.
 *
 * @return
 *   A themed HTML string representing the radio button set.
 *
 * @ingroup themeable
 */
function theme_radios($variables) {
  $element = $variables['element'];
  $class = 'form-radios';
  if (!empty($element['#attributes']['class'])) {
    $class .= ' ' . implode(' ', $element['#attributes']['class']);
  }
  $element['#children'] = '<div class="' . $class . '">' . (!empty($element['#children']) ? $element['#children'] : '') . '</div>';

  return $element['#children'];
}

/**
 * Expand a password_confirm field into two text boxes.
 */
function form_process_password_confirm($element) {
  $element['pass1'] =  array(
    '#type' => 'password',
    '#title' => t('Password'),
    '#value' => empty($element['#value']) ? NULL : $element['#value']['pass1'],
    '#required' => $element['#required'],
    '#attributes' => array('class' => array('password-field')),
  );
  $element['pass2'] =  array(
    '#type' => 'password',
    '#title' => t('Confirm password'),
    '#value' => empty($element['#value']) ? NULL : $element['#value']['pass2'],
    '#required' => $element['#required'],
    '#attributes' => array('class' => array('password-confirm')),
  );
  $element['#element_validate'] = array('password_confirm_validate');
  $element['#tree'] = TRUE;

  if (isset($element['#size'])) {
    $element['pass1']['#size'] = $element['pass2']['#size'] = $element['#size'];
  }

  return $element;
}

/**
 * Validate password_confirm element.
 */
function password_confirm_validate($element, &$element_state) {
  $pass1 = trim($element['pass1']['#value']);
  if (!empty($pass1)) {
    $pass2 = trim($element['pass2']['#value']);
    if (strcmp($pass1, $pass2)) {
      form_error($element, t('The specified passwords do not match.'));
    }
  }
  elseif ($element['#required'] && !empty($element_state['input'])) {
    form_error($element, t('Password field is required.'));
  }

  // Password field must be converted from a two-element array into a single
  // string regardless of validation results.
  form_set_value($element['pass1'], NULL, $element_state);
  form_set_value($element['pass2'], NULL, $element_state);
  form_set_value($element, $pass1, $element_state);

  return $element;

}

/**
 * Theme a date selection form element.
 *
 * @param $variables
 *   An associative array containing:
 *   - element: An associative array containing the properties of the element.
 *     Properties used: #title, #value, #options, #description, #required,
 *     #attributes.
 *
 * @return
 *   A themed HTML string representing the date selection boxes.
 *
 * @ingroup themeable
 */
function theme_date($variables) {
  $element = $variables['element'];
  return '<div class="container-inline">' . drupal_render_children($element) . '</div>';
}

/**
 * Roll out a single date element.
 */
function form_process_date($element) {
  // Default to current date
  if (empty($element['#value'])) {
    $element['#value'] = array('day' => format_date(REQUEST_TIME, 'custom', 'j'),
                            'month' => format_date(REQUEST_TIME, 'custom', 'n'),
                            'year' => format_date(REQUEST_TIME, 'custom', 'Y'));
  }

  $element['#tree'] = TRUE;

  // Determine the order of day, month, year in the site's chosen date format.
  $format = variable_get('date_format_short', 'm/d/Y - H:i');
  $sort = array();
  $sort['day'] = max(strpos($format, 'd'), strpos($format, 'j'));
  $sort['month'] = max(strpos($format, 'm'), strpos($format, 'M'));
  $sort['year'] = strpos($format, 'Y');
  asort($sort);
  $order = array_keys($sort);

  // Output multi-selector for date.
  foreach ($order as $type) {
    switch ($type) {
      case 'day':
        $options = drupal_map_assoc(range(1, 31));
        break;
      case 'month':
        $options = drupal_map_assoc(range(1, 12), 'map_month');
        break;
      case 'year':
        $options = drupal_map_assoc(range(1900, 2050));
        break;
    }

    $element[$type] = array(
      '#type' => 'select',
      '#value' => $element['#value'][$type],
      '#attributes' => $element['#attributes'],
      '#options' => $options,
    );
  }

  return $element;
}

/**
 * Validates the date type to stop dates like February 30, 2006.
 */
function date_validate($form) {
  if (!checkdate($form['#value']['month'], $form['#value']['day'], $form['#value']['year'])) {
    form_error($form, t('The specified date is invalid.'));
  }
}

/**
 * Helper function for usage with drupal_map_assoc to display month names.
 */
function map_month($month) {
  $months = &drupal_static(__FUNCTION__, array(
    1 => 'Jan',
    2 => 'Feb',
    3 => 'Mar',
    4 => 'Apr',
    5 => 'May',
    6 => 'Jun',
    7 => 'Jul',
    8 => 'Aug',
    9 => 'Sep',
    10 => 'Oct',
    11 => 'Nov',
    12 => 'Dec',
  ));
  return t($months[$month]);
}

/**
 * If no default value is set for weight select boxes, use 0.
 */
function weight_value(&$form) {
  if (isset($form['#default_value'])) {
    $form['#value'] = $form['#default_value'];
  }
  else {
    $form['#value'] = 0;
  }
}

/**
 * Roll out a single radios element to a list of radios,
 * using the options array as index.
 */
function form_process_radios($element) {
  if (count($element['#options']) > 0) {
    foreach ($element['#options'] as $key => $choice) {
      if (!isset($element[$key])) {
        // Generate the parents as the autogenerator does, so we will have a
        // unique id for each radio button.
        $parents_for_id = array_merge($element['#parents'], array($key));
        $element[$key] = array(
          '#type' => 'radio',
          '#title' => $choice,
          '#return_value' => check_plain($key),
          '#default_value' => isset($element['#default_value']) ? $element['#default_value'] : NULL,
          '#attributes' => $element['#attributes'],
          '#parents' => $element['#parents'],
          '#id' => drupal_html_id('edit-' . implode('-', $parents_for_id)),
          '#ajax' => isset($element['#ajax']) ? $element['#ajax'] : NULL,
        );
      }
    }
  }
  return $element;
}

/**
 * Add text format selector to text elements with the #text_format property.
 *
 * The #text_format property should be the ID of an text format, found in
 * {filter_format}.format, which gets passed to filter_form().
 *
 * If the property #text_format is set, the form element will be expanded into
 * two separate form elements, one holding the content of the element, and the
 * other holding the text format selector. The original element is shifted into
 * a child element, but is otherwise unaltered, so that the format selector is
 * at the same level as the text field which it affects.
 *
 * For example:
 * @code
 *   // A simple textarea, such as a node body.
 *   $form['body'] = array(
 *     '#type' => 'textarea',
 *     '#title' => t('Body'),
 *     '#text_format' => isset($node->format) ? $node->format : filter_default_format(),
 *   );
 * @endcode
 *
 * Becomes:
 * @code
 *   $form['body'] = array(
 *     // Type switches to 'markup', as we're only interested in submitting the child elements.
 *     '#type' => 'markup',
 *     // 'value' holds the original element.
 *     'value' => array(
 *       '#type' => 'textarea',
 *       '#title' => t('Body'),
 *       '#parents' => array('body'),
 *     ),
 *     // 'format' holds the text format selector.
 *     'format' => array(
 *       '#parents' => array('body_format'),
 *       ...
 *     ),
 *   );
 * @endcode
 *
 * And would result in:
 * @code
 *   // Original, unaltered form element value.
 *   $form_state['values']['body'] = 'Example content';
 *   // Chosen text format.
 *   $form_state['values']['body_format'] = 1;
 * @endcode
 *
 * @see system_element_info(), filter_form()
 */
function form_process_text_format($element) {
  if (isset($element['#text_format'])) {
    // Determine the form element parents and element name to use for the input
    // format widget. This simulates the 'element' and 'element_format' pair of
    // parents that filter_form() expects.
    $element_parents = $element['#parents'];
    $element_name = array_pop($element_parents);
    $element_parents[] = $element_name . '_format';

    // We need to break references, otherwise form_builder recurses infinitely.
    $element['value'] = (array)$element;
    $element['value']['#weight'] = 0;
    unset($element['value']['#description']);
    $element['#type'] = 'markup';
    $element['#theme'] = NULL;
    $element['#theme_wrappers'] = array('text_format_wrapper');
    $element['format'] = filter_form($element['#text_format'], 1, $element_parents);

    // We need to clear the #text_format from the new child otherwise we
    // would get into an infinite loop.
    unset($element['value']['#text_format']);
  }
  return $element;
}

/**
 * Theme a text format form element.
 *
 * @param $variables
 *   An associative array containing:
 *   - element: An associative array containing the properties of the element.
 *     Properties used: #children, #description
 *
 * @return
 *   A string representing the form element.
 *
 * @ingroup themeable
 */
function theme_text_format_wrapper($variables) {
  $element = $variables['element'];
  $output = '<div class="text-format-wrapper">' . "\n";

  $output .= $element['#children'] . "\n";

  if (!empty($element['#description'])) {
    $output .= '<div class="description">' . $element['#description'] . "</div>\n";
  }

  $output .= "</div>\n";

  return $output;
}

/**
 * Theme a checkbox form element.
 *
 * @param $variables
 *   An associative array containing:
 *   - element: An associative array containing the properties of the element.
 *     Properties used: #title, #value, #return_value, #description, #required,
 *     #attributes.
 *
 * @return
 *   A themed HTML string representing the checkbox.
 *
 * @ingroup themeable
 */
function theme_checkbox($variables) {
  $element = $variables['element'];
  $t = get_t();
  _form_set_class($element, array('form-checkbox'));
  $checkbox = '<input ';
  $checkbox .= 'type="checkbox" ';
  $checkbox .= 'name="' . $element['#name'] . '" ';
  $checkbox .= 'id="' . $element['#id'] . '" ' ;
  $checkbox .= 'value="' . $element['#return_value'] . '" ';
  // Unchecked checkbox has #value of numeric 0.
  if ($element['#value'] !== 0 && $element['#value'] == $element['#return_value']) {
    $checkbox .= 'checked="checked" ';
  }
  $checkbox .= drupal_attributes($element['#attributes']) . ' />';

  return $checkbox;
}

/**
 * Theme a set of checkbox form elements.
 *
 * @param $variables
 *   An associative array containing:
 *   - element: An associative array containing the properties of the element.
 *     Properties used: #children, #attributes.
 *
 * @return
 *   A themed HTML string representing the checkbox set.
 *
 * @ingroup themeable
 */
function theme_checkboxes($variables) {
  $element = $variables['element'];
  $class = 'form-checkboxes';
  if (!empty($element['#attributes']['class'])) {
    $class .= ' ' . implode(' ', $element['#attributes']['class']);
  }
  $element['#children'] = '<div class="' . $class . '">' . (!empty($element['#children']) ? $element['#children'] : '') . '</div>';

  return $element['#children'];
}

/**
 * Add form_element theming to an element if title or description is set.
 *
 * This is used as a pre render function for checkboxes and radios.
 */
function form_pre_render_conditional_form_element($element) {
  // Set the element's title attribute to show #title as a tooltip, if needed.
  if (isset($element['#title']) && $element['#title_display'] == 'attribute') {
    $element['#attributes']['title'] = $element['#title'];
    if (!empty($element['#required'])) {
      // Append an indication that this field is required.
      $element['#attributes']['title'] .= ' (' . $t('Required') . ')';
    }
  }

  if (isset($element['#title']) || isset($element['#description'])) {
    unset($element['#id']);
    $element['#theme_wrappers'][] = 'form_element';
  }
  return $element;
}

function form_process_checkboxes($element) {
  $value = is_array($element['#value']) ? $element['#value'] : array();
  $element['#tree'] = TRUE;
  if (count($element['#options']) > 0) {
    if (!isset($element['#default_value']) || $element['#default_value'] == 0) {
      $element['#default_value'] = array();
    }
    foreach ($element['#options'] as $key => $choice) {
      if (!isset($element[$key])) {
        $element[$key] = array(
          '#type' => 'checkbox',
          '#processed' => TRUE,
          '#title' => $choice,
          '#return_value' => $key,
          '#default_value' => isset($value[$key]) ? $key : NULL,
          '#attributes' => $element['#attributes'],
          '#ajax' => isset($element['#ajax']) ? $element['#ajax'] : NULL,
        );
      }
    }
  }
  return $element;
}

/**
 * Processes a container element.
 *
 * @param $element
 *   An associative array containing the properties and children of the
 *   container.
 * @param $form_state
 *   The $form_state array for the form this element belongs to.
 * @return
 *   The processed element.
 */
function form_process_container($element, &$form_state) {
  // Generate the ID of the element if it's not explicitly given.
  if (!isset($element['#id'])) {
    $element['#id'] = drupal_html_id(implode('-', $element['#parents']) . '-wrapper');
  }
  return $element;
}

/**
 * Adds a container for grouped items.
 *
 * @param $variables
 *   An associative array containing:
 *   - element: An associative array containing the properties of the element.
 *     Properties used: #id, #attributes, #children.
 * @return
 *   A themed HTML string representing the form element.
 *
 * @ingroup themeable
 */
function theme_container($variables) {
  $element = $variables['element'];
  if (!isset($element['#attributes']['id'])) {
    $element['#attributes']['id'] = $element['#id'];
  }
  // Force the 'form-wrapper' class.
  $element['#attributes']['class'][] = 'form-wrapper';
  return '<div' . drupal_attributes($element['#attributes']) . '>' . $element['#children'] . '</div>';
}

/**
 * Formats a table with radio buttons or checkboxes.
 *
 * @param $variables
 *   An associative array containing:
 *   - element: An associative array containing the properties and children of
 *     the tableselect element. Properties used: #header, #options, #empty,
 *     and #js_select. The #options property is an array of selection options;
 *     each array element of #options is an array of properties. These
 *     properties can include #attributes, which is added to the
 *     table row's HTML attributes (see theme_table()). Example:
 * @code
 * $options = array();
 * $options[0]['title'] = "A red row"
 * $options[0]['#attributes'] = array ('class' => array('red-row'));
 * $options[1]['title'] = "A blue row"
 * $options[1]['#attributes'] = array ('class' => array('blue-row'));
 *
 * $form['myselector'] = array (
 * '#type' => 'tableselect',
 * '#title' => 'My Selector'
 * '#options' => $options,
 * );
 * @endcode
 *
 * @return
 *   A themed HTML string representing the table.
 *
 * @ingroup themeable
 */
function theme_tableselect($variables) {
  $element = $variables['element'];
  $rows = array();
  $header = $element['#header'];
  if (!empty($element['#options'])) {
    // Generate a table row for each selectable item in #options.
    foreach ($element['#options'] as $key => $value) {
      $row = array();

      $row['data'] = array();
      if (isset($value['#attributes'])) {
        $row += $value['#attributes'];
      }
      // Render the checkbox / radio element.
      $row['data'][] = drupal_render($element[$key]);

      // As theme_table only maps header and row columns by order, create the
      // correct order by iterating over the header fields.
      foreach ($element['#header'] as $fieldname => $title) {
        $row['data'][] = $element['#options'][$key][$fieldname];
      }
      $rows[] = $row;
    }
    // Add an empty header or a "Select all" checkbox to provide room for the
    // checkboxes/radios in the first table column.
    $first_col = $element['#js_select'] ? array(theme('table_select_header_cell')) : array('');
    $header = array_merge($first_col, $header);
  }
  return theme('table', array('header' => $header, 'rows' => $rows, 'empty' => $element['#empty'], 'attributes' => $element['#attributes']));
}

/**
 * Create the correct amount of checkbox or radio elements to populate the table.
 *
 * @param $element
 *   An associative array containing the properties and children of the
 *   tableselect element.
 * @return
 *   The processed element.
 */
function form_process_tableselect($element) {

  if ($element['#multiple']) {
    $value = is_array($element['#value']) ? $element['#value'] : array();
  }
  else {
    // Advanced selection behaviour make no sense for radios.
    $element['#js_select'] = FALSE;
  }

  $element['#tree'] = TRUE;

  if (count($element['#options']) > 0) {
    if (!isset($element['#default_value']) || $element['#default_value'] === 0) {
      $element['#default_value'] = array();
    }

    // Sort the options by their #weight if they have a #weight.
    uasort($element['#options'], 'element_sort');
    // Create a checkbox or radio for each item in #options in such a way that
    // the value of the tableselect element behaves as if it had been of type
    // checkboxes or radios.
    foreach ($element['#options'] as $key => $choice) {
      // Do not overwrite manually created children.
      if (!isset($element[$key])) {
        if ($element['#multiple']) {
          $element[$key] = array(
            '#type' => 'checkbox',
            '#title' => '',
            '#return_value' => $key,
            '#default_value' => isset($value[$key]) ? $key : NULL,
            '#attributes' => $element['#attributes'],
            '#ajax' => isset($element['#ajax']) ? $element['#ajax'] : NULL,
          );
        }
        else {
          // Generate the parents as the autogenerator does, so we will have a
          // unique id for each radio button.
          $parents_for_id = array_merge($element['#parents'], array($key));
          $element[$key] = array(
            '#type' => 'radio',
            '#title' => '',
            '#return_value' => $key,
            '#default_value' => ($element['#default_value'] == $key) ? $key : NULL,
            '#attributes' => $element['#attributes'],
            '#parents' => $element['#parents'],
            '#id' => drupal_html_id('edit-' . implode('-', $parents_for_id)),
            '#ajax' => isset($element['#ajax']) ? $element['#ajax'] : NULL,
          );
        }
      }
    }
  }
  else {
    $element['#value'] = array();
  }
  return $element;
}

/**
 * Adds fieldsets to the specified group or adds group members to this
 * fieldset.
 *
 * @param &$element
 *   An associative array containing the properties and children of the
 *   fieldset. Note that $element must be taken by reference here, so processed
 *   child elements are taken over into $form_state.
 * @param $form_state
 *   The $form_state array for the form this fieldset belongs to.
 * @return
 *   The processed element.
 */
function form_process_fieldset(&$element, &$form_state) {
  $parents = implode('][', $element['#parents']);

  // Each fieldset forms a new group. The #type 'vertical_tabs' basically only
  // injects a new fieldset.
  $form_state['groups'][$parents]['#group_exists'] = TRUE;
  $element['#groups'] = &$form_state['groups'];

  // Process vertical tabs group member fieldsets.
  if (isset($element['#group'])) {
    // Add this fieldset to the defined group (by reference).
    $group = $element['#group'];
    $form_state['groups'][$group][] = &$element;
  }

  // Contains form element summary functionalities.
  $element['#attached']['js']['misc/form.js'] = array('weight' => JS_LIBRARY + 1);

  // Collapsible fieldsets
  if (!empty($element['#collapsible'])) {
    $element['#attached']['js'][] = 'misc/collapse.js';
    if (!isset($element['#attributes']['class'])) {
      $element['#attributes']['class'] = array();
    }

    $element['#attributes']['class'][] = 'collapsible';
    if (!empty($element['#collapsed'])) {
      $element['#attributes']['class'][] = 'collapsed';
    }
  }
  $element['#attributes']['id'] = $element['#id'];

  return $element;
}

/**
 * Adds members of this group as actual elements for rendering.
 *
 * @param $element
 *   An associative array containing the properties and children of the
 *   fieldset.
 *
 * @return
 *   The modified element with all group members.
 */
function form_pre_render_fieldset($element) {
  // Inject group member elements belonging to this group.
  $parents = implode('][', $element['#parents']);
  $children = element_children($element['#groups'][$parents]);
  if (!empty($children)) {
    foreach ($children as $key) {
      // Break references and indicate that the element should be rendered as
      // group member.
      $child = (array) $element['#groups'][$parents][$key];
      $child['#group_fieldset'] = TRUE;
      // Inject the element as new child element.
      $element[] = $child;

      $sort = TRUE;
    }
    // Re-sort the element's children if we injected group member elements.
    if (isset($sort)) {
      $element['#sorted'] = FALSE;
    }
  }

  if (isset($element['#group'])) {
    $group = $element['#group'];
    // If this element belongs to a group, but the group-holding element does
    // not exist, we need to render it (at its original location).
    if (!isset($element['#groups'][$group]['#group_exists'])) {
      // Intentionally empty to clarify the flow; we simply return $element.
    }
    // If we injected this element into the group, then we want to render it.
    elseif (!empty($element['#group_fieldset'])) {
      // Intentionally empty to clarify the flow; we simply return $element.
    }
    // Otherwise, this element belongs to a group and the group exists, so we do
    // not render it.
    elseif (element_children($element['#groups'][$group])) {
      $element['#printed'] = TRUE;
    }
  }

  return $element;
}

/**
 * Creates a group formatted as vertical tabs.
 *
 * @param $element
 *   An associative array containing the properties and children of the
 *   fieldset.
 * @param $form_state
 *   The $form_state array for the form this vertical tab widget belongs to.
 * @return
 *   The processed element.
 */
function form_process_vertical_tabs($element, &$form_state) {
  // Inject a new fieldset as child, so that form_process_fieldset() processes
  // this fieldset like any other fieldset.
  $element['group'] = array(
    '#type' => 'fieldset',
    '#theme_wrappers' => array(),
    '#parents' => $element['#parents'],
  );

  // The JavaScript stores the currently selected tab in this hidden
  // field so that the active tab can be restored the next time the
  // form is rendered, e.g. on preview pages or when form validation
  // fails.
  $name = implode('__', $element['#parents']);
  if (isset($form_state['values'][$name . '__active_tab'])) {
    $element['#default_tab'] = $form_state['values'][$name . '__active_tab'];
  }
  $element[$name . '__active_tab'] = array(
    '#type' => 'hidden',
    '#default_value' => $element['#default_tab'],
    '#attributes' => array('class' => array('vertical-tabs-active-tab')),
  );

  return $element;
}

/**
 * Makes the element's children fieldsets be vertical tabs.
 *
 * @param $variables
 *   An associative array containing:
 *   - element: An associative array containing the properties and children of the
 *     fieldset. Properties used: #children.
 *
 * @return
 *   A themed HTML string representing the form element.
 *
 * @ingroup themeable
 */
function theme_vertical_tabs($variables) {
  $element = $variables['element'];
  // Add required JavaScript and Stylesheet.
  drupal_add_library('system', 'vertical-tabs');

  return '<div class="vertical-tabs-panes">' . $element['#children'] . '</div>';
}

/**
 * Theme a submit button form element.
 *
 * @param $variables
 *   An associative array containing:
 *   - element: An associative array containing the properties of the element.
 *     Properties used: #attributes, #button_type, #name, #value.
 *
 * @return
 *   A themed HTML string representing the form element.
 *
 * @ingroup themeable
 */
function theme_submit($variables) {
  $element = $variables['element'];
  return theme('button', $element);
}

/**
 * Theme a button form element.
 *
 * @param $variables
 *   An associative array containing:
 *   - element: An associative array containing the properties of the element.
 *     Properties used: #attributes, #button_type, #name, #value.
 *
 * @return
 *   A themed HTML string representing the form element.
 *
 * @ingroup themeable
 */
function theme_button($variables) {
  $element = $variables['element'];
  $element['#attributes']['class'][] = 'form-' . $element['#button_type'];

  return '<input type="submit" ' . (empty($element['#name']) ? '' : 'name="' . $element['#name'] . '" ') . 'id="' . $element['#id'] . '" value="' . check_plain($element['#value']) . '" ' . drupal_attributes($element['#attributes']) . " />\n";
}

/**
 * Theme a image button form element.
 *
 * @param $variables
 *   An associative array containing:
 *   - element: An associative array containing the properties of the element.
 *     Properties used: #attributes, #button_type, #name, #value, #title, #src.
 *
 * @return
 *   A themed HTML string representing the form element.
 * @ingroup themeable
 */
function theme_image_button($variables) {
  $element = $variables['element'];
  $element['#attributes']['class'][] = 'form-' . $element['#button_type'];

  return '<input type="image" name="' . $element['#name'] . '" ' .
    (!empty($element['#value']) ? ('value="' . check_plain($element['#value']) . '" ') : '') .
    'id="' . $element['#id'] . '" ' .
    drupal_attributes($element['#attributes']) .
    ' src="' . file_create_url($element['#src']) . '" ' .
    (!empty($element['#title']) ? 'alt="' . check_plain($element['#title']) . '" title="' . check_plain($element['#title']) . '" ' : '' ) .
    "/>\n";
}

/**
 * Theme a hidden form element.
 *
 * @param $variables
 *   An associative array containing:
 *   - element: An associative array containing the properties of the element.
 *     Properties used: #name, #value, #attributes.
 *
 * @return
 *   A themed HTML string representing the form element.
 *
 * @ingroup themeable
 */
function theme_hidden($variables) {
  $element = $variables['element'];
  return '<input type="hidden" name="' . $element['#name'] . '" id="' . $element['#id'] . '" value="' . check_plain($element['#value']) . "\" " . drupal_attributes($element['#attributes']) . " />\n";
}

/**
 * Theme a textfield form element.
 *
 * @param $variables
 *   An associative array containing:
 *   - element: An associative array containing the properties of the element.
 *     Properties used: #title, #value, #description, #size, #maxlength,
 *     #required, #attributes, #autocomplete_path.
 *
 * @return
 *   A themed HTML string representing the textfield.
 *
 * @ingroup themeable
 */
function theme_textfield($variables) {
  $element = $variables['element'];
  $size = empty($element['#size']) ? '' : ' size="' . $element['#size'] . '"';
  $maxlength = empty($element['#maxlength']) ? '' : ' maxlength="' . $element['#maxlength'] . '"';
  $class = array('form-text');
  $extra = '';
  $output = '';

  if ($element['#autocomplete_path'] && drupal_valid_path($element['#autocomplete_path'])) {
    drupal_add_js('misc/autocomplete.js');
    $class[] = 'form-autocomplete';
    $extra =  '<input class="autocomplete" type="hidden" id="' . $element['#id'] . '-autocomplete" value="' . check_url(url($element['#autocomplete_path'], array('absolute' => TRUE))) . '" disabled="disabled" />';
  }
  _form_set_class($element, $class);

  if (isset($element['#field_prefix'])) {
    $output .= '<span class="field-prefix">' . $element['#field_prefix'] . '</span> ';
  }

  $output .= '<input type="text"' . $maxlength . ' name="' . $element['#name'] . '" id="' . $element['#id'] . '"' . $size . ' value="' . check_plain($element['#value']) . '"' . drupal_attributes($element['#attributes']) . ' />';

  if (isset($element['#field_suffix'])) {
    $output .= ' <span class="field-suffix">' . $element['#field_suffix'] . '</span>';
  }
  return $output . $extra;
}

/**
 * Theme a form.
 *
 * @param $variables
 *   An associative array containing:
 *   - element: An associative array containing the properties of the element.
 *     Properties used: #action, #method, #attributes, #children
 *
 * @return
 *   A themed HTML string representing the form.
 *
 * @ingroup themeable
 */
function theme_form($variables) {
  $element = $variables['element'];
  // Anonymous div to satisfy XHTML compliance.
  $action = $element['#action'] ? 'action="' . check_url($element['#action']) . '" ' : '';
  return '<form ' . $action . ' accept-charset="UTF-8" method="' . $element['#method'] . '" id="' . $element['#id'] . '"' . drupal_attributes($element['#attributes']) . ">\n<div>" . $element['#children'] . "\n</div></form>\n";
}

/**
 * Theme a textarea form element.
 *
 * @param $variables
 *   An associative array containing:
 *   - element: An associative array containing the properties of the element.
 *     Properties used: #title, #value, #description, #rows, #cols, #required,
 *     #attributes
 *
 * @return
 *   A themed HTML string representing the textarea.
 *
 * @ingroup themeable
 */
function theme_textarea($variables) {
  $element = $variables['element'];
  $class = array('form-textarea');

  // Add resizable behavior
  if ($element['#resizable'] !== FALSE) {
    drupal_add_js('misc/textarea.js');
    $class[] = 'resizable';
  }

  _form_set_class($element, $class);
  return '<textarea cols="' . $element['#cols'] . '" rows="' . $element['#rows'] . '" name="' . $element['#name'] . '" id="' . $element['#id'] . '" ' . drupal_attributes($element['#attributes']) . '>' . check_plain($element['#value']) . '</textarea>';
}

/**
 * Theme a password form element.
 *
 * @param $variables
 *   An associative array containing:
 *   - element: An associative array containing the properties of the element.
 *     Properties used: #title, #value, #description, #size, #maxlength,
 *     #required, #attributes.
 *
 * @return
 *   A themed HTML string representing the form element.
 *
 * @ingroup themeable
 */
function theme_password($variables) {
  $element = $variables['element'];
  $size = $element['#size'] ? ' size="' . $element['#size'] . '" ' : '';
  $maxlength = $element['#maxlength'] ? ' maxlength="' . $element['#maxlength'] . '" ' : '';

  _form_set_class($element, array('form-text'));
  $output = '<input type="password" name="' . $element['#name'] . '" id="' . $element['#id'] . '" ' . $maxlength . $size . drupal_attributes($element['#attributes']) . ' />';
  return $output;
}

/**
 * Expand weight elements into selects.
 */
function form_process_weight($element) {
  for ($n = (-1 * $element['#delta']); $n <= $element['#delta']; $n++) {
    $weights[$n] = $n;
  }
  $element['#options'] = $weights;
  $element['#type'] = 'select';
  $element['#is_weight'] = TRUE;
  $element += element_info('select');
  return $element;
}

/**
 * Theme a file upload form element.
 *
 * @param $variables
 *   An associative array containing:
 *   - element: An associative array containing the properties of the element.
 *     Properties used: #title, #name, #size, #description, #required,
 *     #attributes.
 *
 * @return
 *   A themed HTML string representing the field.
 *
 * @ingroup themeable
 *
 * For assistance with handling the uploaded file correctly, see the API
 * provided by file.inc.
 */
function theme_file($variables) {
  $element = $variables['element'];
  _form_set_class($element, array('form-file'));
  return '<input type="file" name="' . $element['#name'] . '"' . ($element['#attributes'] ? ' ' . drupal_attributes($element['#attributes']) : '') . ' id="' . $element['#id'] . '" size="' . $element['#size'] . "\" />\n";
}

/**
 * Theme a form element.
 *
 * Each form element is wrapped in a DIV with #type and #name classes. In
 * addition to the element itself, the div contains a label before or after
 * the element based on the optional #title_display property. After the label
 * and fields this function outputs the optional element #description.
 *
 * The optional #title_display property can have these values:
 * - before: The label is output before the element. This is the default.
 *   The label includes the #title and the required marker, if #required.
 * - after: The label is output after the element. For example, this is used
 *   for radio and checkbox #type elements as set in system_element_info().
 *   If the #title is empty but the field is #required, the label will
 *   contain only the required marker.
 * - attribute: Set the title attribute on the element to create a tooltip
 *   but output no label element. This is supported only for checkboxes
 *   and radios in form_pre_render_conditional_form_element(). It is used
 *   where a visual label is not needed, such as a table of checkboxes where
 *   the row and column provide the context. The tooltip will include the
 *   title and required marker.
 *
 * If the #title property is not set, then the label and any required marker
 * will not be output, regardless of the #title_display or #required values.
 * This can be useful in cases such as the password_confirm element, which
 * creates children elements that have their own labels and required markers,
 * but the parent element should have neither. Use this carefully because a
 * field without an associated label can cause accessibility challenges.
 *
 * @param $variables
 *   An associative array containing:
 *   - element: An associative array containing the properties of the element.
 *     Properties used: #title, #title_display, #description, #id, #required,
 *     #children, #type, #name.
 *
 * @return
 *   A string representing the form element.
 *
 * @ingroup themeable
 */
function theme_form_element($variables) {
  $element = $variables['element'];
  // This is also used in the installer, pre-database setup.
  $t = get_t();

  // Add element's #type and #name as class to aid with JS/CSS selectors.
  $class = array('form-item');
  if (!empty($element['#type'])) {
    $class[] = 'form-type-' . strtr($element['#type'], '_', '-');
  }
  if (!empty($element['#name'])) {
    $class[] = 'form-item-' . strtr($element['#name'], array(' ' => '-', '_' => '-', '[' => '-', ']' => ''));
  }

  // If #title is not set, we don't display any label or required marker.
  if (!isset($element['#title'])) {
    $element['#title_display'] = 'none';
  }

  $output = '<div class="' . implode(' ', $class) . '">' . "\n";

  switch ($element['#title_display']) {
    case 'before':
      $output .= ' ' . theme('form_element_label', $variables);
      $output .= ' ' . $element['#children'] . "\n";
      break;

    case 'after':
      $output .= ' ' . $element['#children'];
      $output .= ' ' . theme('form_element_label', $variables) . "\n";
      break;

    case 'none':
    case 'attribute':
      // Output no label and no required marker, only the children.
      $output .= ' ' . $element['#children'] . "\n";
      break;
  }

  if (!empty($element['#description'])) {
    $output .= ' <div class="description">' . $element['#description'] . "</div>\n";
  }

  $output .= "</div>\n";

  return $output;
}

/**
 * Theme the marker for required form elements.
 *
 * @param $variables
 *   An associative array containing:
 *   - element: An associative array containing the properties of the element.
 * @return
 *   A string representing the marker to identify required form elements.
 *
 * @ingroup themeable
 */
function theme_form_required_marker($variables) {
  // This is also used in the installer, pre-database setup.
  $t = get_t();
  $attributes = array(
    'class' => 'form-required',
    'title' => $t('This field is required.'),
  );
  return '<span' . drupal_attributes($attributes) . '>*</span>';
}

/**
 * Theme a form element label and required marker.
 *
 * Form element labels include the #title and a #required marker. The label is
 * associated with the element itself by the element #id. Labels may appear
 * before or after elements, depending on theme_form_element() and #title_display.
 *
 * This function will not be called for elements with no labels, depending on
 * #title_display. For elements that have an empty #title and are not required,
 * this function will output no label (''). For required elements that have an
 * empty #title, this will output the required marker alone within the label.
 * The label will use the #id to associate the marker with the field that is
 * required. That is especially important for screenreader users to know
 * which field is required.
 *
 * @param $variables
 *   An associative array containing:
 *   - element: An associative array containing the properties of the element.
 *     Properties used: #required, #title, #id, #value, #description.
 * @return
 *   A string representing the form element label.
 *
 * @ingroup themeable
 */
function theme_form_element_label($variables) {
  $element = $variables['element'];
  // This is also used in the installer, pre-database setup.
  $t = get_t();

  // If title and required marker are both empty, output no label.
  if (empty($element['#title']) && empty($element['#required'])) {
    return '';
  }

  // If the element is required, a required marker is appended to the label.
  $required = !empty($element['#required']) ? theme('form_required_marker', array('element' => $element)) : '';

  $title = filter_xss_admin($element['#title']);

  $attributes = array();
  if ($element['#title_display'] == 'after') {
    // Style the label as class option to display inline with the element.
    $attributes['class'] = 'option';
  }
  if (!empty($element['#id'])) {
    $attributes['for'] = $element['#id'];
  }

  // The leading whitespace helps visually separate fields from inline labels.
  return ' <label' . drupal_attributes($attributes) . '>' . $t('!title !required', array('!title' => $title, '!required' => $required)) . "</label>\n";
}

/**
 * Sets a form element's class attribute.
 *
 * Adds 'required' and 'error' classes as needed.
 *
 * @param &$element
 *   The form element.
 * @param $name
 *   Array of new class names to be added.
 */
function _form_set_class(&$element, $class = array()) {
  if (!empty($class)) {
    if (!isset($element['#attributes']['class'])) {
      $element['#attributes']['class'] = array();
    }
    $element['#attributes']['class'] = array_merge($element['#attributes']['class'], $class);
  }
  if ($element['#required']) {
    $element['#attributes']['class'][] = 'required';
  }
  if (form_get_error($element)) {
    $element['#attributes']['class'][] = 'error';
  }
}

/**
 * @} End of "defgroup form_api".
 */

/**
 * @defgroup batch Batch operations
 * @{
 * Functions allowing forms processing to be spread out over several page
 * requests, thus ensuring that the processing does not get interrupted
 * because of a PHP timeout, while allowing the user to receive feedback
 * on the progress of the ongoing operations.
 *
 * The API is primarily designed to integrate nicely with the Form API
 * workflow, but can also be used by non-FAPI scripts (like update.php)
 * or even simple page callbacks (which should probably be used sparingly).
 *
 * Example:
 * @code
 * $batch = array(
 *   'title' => t('Exporting'),
 *   'operations' => array(
 *     array('my_function_1', array($account->uid, 'story')),
 *     array('my_function_2', array()),
 *   ),
 *   'finished' => 'my_finished_callback',
 *   'file' => 'path_to_file_containing_myfunctions',
 * );
 * batch_set($batch);
 * // only needed if not inside a form _submit handler :
 * batch_process();
 * @endcode
 *
 * Note: if the batch 'title', 'init_message', 'progress_message', or
 * 'error_message' could contain any user input, it is the responsibility of
 * the code calling batch_set() to sanitize them first with a function like
 * check_plain() or filter_xss().
 *
 * Sample batch operations:
 * @code
 * // Simple and artificial: load a node of a given type for a given user
 * function my_function_1($uid, $type, &$context) {
 *   // The $context array gathers batch context information about the execution (read),
 *   // as well as 'return values' for the current operation (write)
 *   // The following keys are provided :
 *   // 'results' (read / write): The array of results gathered so far by
 *   //   the batch processing, for the current operation to append its own.
 *   // 'message' (write): A text message displayed in the progress page.
 *   // The following keys allow for multi-step operations :
 *   // 'sandbox' (read / write): An array that can be freely used to
 *   //   store persistent data between iterations. It is recommended to
 *   //   use this instead of $_SESSION, which is unsafe if the user
 *   //   continues browsing in a separate window while the batch is processing.
 *   // 'finished' (write): A float number between 0 and 1 informing
 *   //   the processing engine of the completion level for the operation.
 *   //   1 (or no value explicitly set) means the operation is finished
 *   //   and the batch processing can continue to the next operation.
 *
 *   $node = node_load(array('uid' => $uid, 'type' => $type));
 *   $context['results'][] = $node->nid . ' : ' . $node->title;
 *   $context['message'] = $node->title;
 * }
 *
 * // More advanced example: multi-step operation - load all nodes, five by five
 * function my_function_2(&$context) {
 *   if (empty($context['sandbox'])) {
 *     $context['sandbox']['progress'] = 0;
 *     $context['sandbox']['current_node'] = 0;
 *     $context['sandbox']['max'] = db_query('SELECT COUNT(DISTINCT nid) FROM {node}')->fetchField();
 *   }
 *   $limit = 5;
 *   $result = db_select('node')
 *     ->fields('node', array('nid'))
 *     ->condition('nid', $context['sandbox']['current_node'], '>')
 *     ->orderBy('nid')
 *     ->range(0, $limit)
 *     ->execute();
 *   foreach ($result as $row) {
 *     $node = node_load($row->nid, NULL, TRUE);
 *     $context['results'][] = $node->nid . ' : ' . $node->title;
 *     $context['sandbox']['progress']++;
 *     $context['sandbox']['current_node'] = $node->nid;
 *     $context['message'] = $node->title;
 *   }
 *   if ($context['sandbox']['progress'] != $context['sandbox']['max']) {
 *     $context['finished'] = $context['sandbox']['progress'] / $context['sandbox']['max'];
 *   }
 * }
 * @endcode
 *
 * Sample 'finished' callback:
 * @code
 * function batch_test_finished($success, $results, $operations) {
 *   if ($success) {
 *     $message = format_plural(count($results), 'One post processed.', '@count posts processed.');
 *   }
 *   else {
 *     $message = t('Finished with an error.');
 *   }
 *   drupal_set_message($message);
 *   // Providing data for the redirected page is done through $_SESSION.
 *   foreach ($results as $result) {
 *     $items[] = t('Loaded node %title.', array('%title' => $result));
 *   }
 *   $_SESSION['my_batch_results'] = $items;
 * }
 * @endcode
 */

/**
 * Opens a new batch.
 *
 * @param $batch
 *   An array defining the batch. The following keys can be used -- only
 *   'operations' is required, and batch_init() provides default values for
 *   the messages.
 *   - 'operations': Array of function calls to be performed.
 *     Example:
 *     @code
 *     array(
 *       array('my_function_1', array($arg1)),
 *       array('my_function_2', array($arg2_1, $arg2_2)),
 *     )
 *     @endcode
 *   - 'title': Title for the progress page. Only safe strings should be passed.
 *     Defaults to t('Processing').
 *   - 'init_message': Message displayed while the processing is initialized.
 *     Defaults to t('Initializing.').
 *   - 'progress_message': Message displayed while processing the batch.
 *     Available placeholders are @current, @remaining, @total, @percentage,
 *     @estimate and @elapsed. Defaults to t('Completed @current of @total.').
 *   - 'error_message': Message displayed if an error occurred while processing
 *     the batch. Defaults to t('An error has occurred.').
 *   - 'finished': Name of a function to be executed after the batch has
 *     completed. This should be used to perform any result massaging that
 *     may be needed, and possibly save data in $_SESSION for display after
 *     final page redirection.
 *   - 'file': Path to the file containing the definitions of the
 *     'operations' and 'finished' functions, for instance if they don't
 *     reside in the main .module file. The path should be relative to
 *     base_path(), and thus should be built using drupal_get_path().
 *   - 'css': Array of paths to CSS files to be used on the progress page.
 *   - 'url_options': options passed to url() when constructing redirect
 *     URLs for the batch.
 *
 * Operations are added as new batch sets. Batch sets are used to ensure
 * clean code independence, ensuring that several batches submitted by
 * different parts of the code (core / contrib modules) can be processed
 * correctly while not interfering or having to cope with each other. Each
 * batch set gets to specify his own UI messages, operates on its own set
 * of operations and results, and triggers its own 'finished' callback.
 * Batch sets are processed sequentially, with the progress bar starting
 * fresh for every new set.
 */
function batch_set($batch_definition) {
  if ($batch_definition) {
    $batch =& batch_get();

    // Initialize the batch if needed.
    if (empty($batch)) {
      $batch = array(
        'sets' => array(),
        'has_form_submits' => FALSE,
      );
    }

    // Base and default properties for the batch set.
    // Use get_t() to allow batches at install time.
    $t = get_t();
    $init = array(
      'sandbox' => array(),
      'results' => array(),
      'success' => FALSE,
      'start' => 0,
      'elapsed' => 0,
    );
    $defaults = array(
      'title' => $t('Processing'),
      'init_message' => $t('Initializing.'),
      'progress_message' => $t('Completed @current of @total.'),
      'error_message' => $t('An error has occurred.'),
      'css' => array(),
    );
    $batch_set = $init + $batch_definition + $defaults;

    // Tweak init_message to avoid the bottom of the page flickering down after
    // init phase.
    $batch_set['init_message'] .= '<br/>&nbsp;';

    // The non-concurrent workflow of batch execution allows us to save
    // numberOfItems() queries by handling our own counter.
    $batch_set['total'] = count($batch_set['operations']);
    $batch_set['count'] = $batch_set['total'];

    // Add the set to the batch.
    if (empty($batch['id'])) {
      // The batch is not running yet. Simply add the new set.
      $batch['sets'][] = $batch_set;
    }
    else {
      // The set is being added while the batch is running. Insert the new set
      // right after the current one to ensure execution order, and store its
      // operations in a queue.
      $index = $batch['current_set'] + 1;
      $slice1 = array_slice($batch['sets'], 0, $index);
      $slice2 = array_slice($batch['sets'], $index);
      $batch['sets'] = array_merge($slice1, array($batch_set), $slice2);
      _batch_populate_queue($batch, $index);
    }
  }
}

/**
 * Processes the batch.
 *
 * Unless the batch has been marked with 'progressive' = FALSE, the function
 * issues a drupal_goto and thus ends page execution.
 *
 * This function is generally not needed in form submit handlers;
 * Form API takes care of batches that were set during form submission.
 *
 * @param $redirect
 *   (optional) Path to redirect to when the batch has finished processing.
 * @param $url
 *   (optional - should only be used for separate scripts like update.php)
 *   URL of the batch processing page.
 * @param $redirect_callback
 *   (optional) Specify a function to be called to redirect to the progressive
 *   processing page. By default drupal_goto() will be used to redirect to a
 *   page which will do the progressive page. Specifying another function will
 *   allow the progressive processing to be processed differently.
 */
function batch_process($redirect = NULL, $url = 'batch', $redirect_callback = 'drupal_goto') {
  $batch =& batch_get();

  drupal_theme_initialize();

  if (isset($batch)) {
    // Add process information
    $process_info = array(
      'current_set' => 0,
      'progressive' => TRUE,
      'url' => $url,
      'url_options' => array(),
      'source_url' => $_GET['q'],
      'redirect' => $redirect,
      'theme' => $GLOBALS['theme_key'],
      'redirect_callback' => $redirect_callback,
    );
    $batch += $process_info;

    // The batch is now completely built. Allow other modules to make changes
    // to the batch so that it is easier to reuse batch processes in other
    // environments.
    drupal_alter('batch', $batch);

    // Assign an arbitrary id: don't rely on a serial column in the 'batch'
    // table, since non-progressive batches skip database storage completely.
    $batch['id'] = db_next_id();

    // Move operations to a job queue. Non-progressive batches will use a
    // memory-based queue.
    foreach ($batch['sets'] as $key => $batch_set) {
      _batch_populate_queue($batch, $key);
    }

    // Initiate processing.
    if ($batch['progressive']) {
      // Now that we have a batch id, we can generate the redirection link in
      // the generic error message.
      $t = get_t();
      $batch['error_message'] = $t('Please continue to <a href="@error_url">the error page</a>', array('@error_url' => url($url, array('query' => array('id' => $batch['id'], 'op' => 'finished')))));

      // Clear the way for the drupal_goto() redirection to the batch processing
      // page, by saving and unsetting the 'destination', if there is any.
      if (isset($_GET['destination'])) {
        $batch['destination'] = $_GET['destination'];
        unset($_GET['destination']);
      }

      // Store the batch.
      db_insert('batch')
        ->fields(array(
          'bid' => $batch['id'],
          'timestamp' => REQUEST_TIME,
          'token' => drupal_get_token($batch['id']),
          'batch' => serialize($batch),
        ))
        ->execute();

      // Set the batch number in the session to guarantee that it will stay alive.
      $_SESSION['batches'][$batch['id']] = TRUE;

      // Redirect for processing.
      $function = $batch['redirect_callback'];
      if (function_exists($function)) {
        $function($batch['url'], array('query' => array('op' => 'start', 'id' => $batch['id'])));
      }
    }
    else {
      // Non-progressive execution: bypass the whole progressbar workflow
      // and execute the batch in one pass.
      require_once DRUPAL_ROOT . '/includes/batch.inc';
      _batch_process();
    }
  }
}

/**
 * Retrieves the current batch.
 */
function &batch_get() {
  // Not drupal_static(), because Batch API operates at a lower level than most
  // use-cases for resetting static variables, and we specifically do not want a
  // global drupal_static_reset() resetting the batch information. Functions
  // that are part of the Batch API and need to reset the batch information may
  // call batch_get() and manipulate the result by reference. Functions that are
  // not part of the Batch API can also do this, but shouldn't.
  static $batch = array();
  return $batch;
}

/**
 * Populates a job queue with the operations of a batch set.
 *
 * Depending on whether the batch is progressive or not, the BatchQueue or
 * BatchStaticQueue handler classes will be used.
 *
 * @param $batch
 *   The batch array.
 * @param $set_id
 *   The id of the set to process.
 * @return
 *   The name and class of the queue are added by reference to the batch set.
 */
function _batch_populate_queue(&$batch, $set_id) {
  $batch_set = &$batch['sets'][$set_id];

  if (isset($batch_set['operations'])) {
    $batch_set += array(
      'queue' => array(
        'name' => 'drupal_batch:' . $batch['id'] . ':' . $set_id,
        'class' => $batch['progressive'] ? 'BatchQueue' : 'BatchMemoryQueue',
      ),
    );

    $queue = _batch_queue($batch_set);
    $queue->createQueue();
    foreach ($batch_set['operations'] as $operation) {
      $queue->createItem($operation);
    }

    unset($batch_set['operations']);
  }
}

/**
 * Returns a queue object for a batch set.
 *
 * @param $batch_set
 *   The batch set.
 * @return
 *   The queue object.
 */
function _batch_queue($batch_set) {
  static $queues;

  // The class autoloader is not available when running update.php, so make
  // sure the files are manually included.
  if (is_null($queues)) {
    $queues = array();
    require_once DRUPAL_ROOT . '/modules/system/system.queue.inc';
    require_once DRUPAL_ROOT . '/includes/batch.queue.inc';
  }

  if (isset($batch_set['queue'])) {
    $name = $batch_set['queue']['name'];
    $class = $batch_set['queue']['class'];

    if (!isset($queues[$class][$name])) {
      $queues[$class][$name] = new $class($name);
    }
    return $queues[$class][$name];
  }
}

/**
 * @} End of "defgroup batch".
 */