defr/drupal/core: includes/form.inc comparison

comparison includes/form.inc @ 1:c1f4ac30525a 6.0

Drupal 6.0

author	Franck Deroche <webmaster@defr.org>
date	Tue, 23 Dec 2008 14:28:28 +0100
parents
children	fff6d4c8c043

comparison

equal deleted inserted replaced

-:5a113a1c4740
+:c1f4ac30525a
+<?php
+// $Id: form.inc,v 1.265.2.4 2008/02/11 14:45:57 goba Exp $
+/**
+* @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, processing, and
+* displaying a rendered HTML form for modules automatically. For example:
+*
+* @code
+* // Display the user registration form.
+* $output = drupal_get_form('user_register');
+* @endcode
+*
+* Forms can also be built and submitted programmatically without any user input
+* using the drupal_execute() 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
+*/
+/**
+* Retrieves a form from a constructor function, or from the cache if
+* the form was built in a previous page-load. The form is then passesed
+* on for processing, after and rendered for display if necessary.
+*
+* @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 $form_id values to the proper form constructor function. Examples
+*   may be found in node_forms(), search_forms(), and user_forms().
+* @param ...
+*   Any additional arguments are passed on to the functions called by
+*   drupal_get_form(), including the unique form constructor function.
+*   For example, the node_edit form requires that a node object be passed
+*   in here when it is called.
+* @return
+*   The rendered form.
+*/
+function drupal_get_form($form_id) {
+$form_state = array('storage' => NULL, 'submitted' => FALSE);
+$args = func_get_args();
+$cacheable = FALSE;
+if (isset($_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 $_POST contains a form_build_id, we'll check the
+// cache for a copy of the form in question. If it's there, we don't
+// have to rebuild the form to proceed. In addition, if there is stored
+// form_state data from a previous step, we'll retrieve it so it can
+// be passed on to the form processing code.
+if (isset($_POST['form_id']) && $_POST['form_id'] == $form_id && !empty($_POST['form_build_id'])) {
+$form = form_get_cache($_POST['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)) {
+$form_state['post'] = $_POST;
+// Use a copy of the function's arguments for manipulation
+$args_temp = $args;
+$args_temp[0] = &$form_state;
+array_unshift($args_temp, $form_id);
+$form = call_user_func_array('drupal_retrieve_form', $args_temp);
+$form_build_id = 'form-'. md5(mt_rand());
+$form['#build_id'] = $form_build_id;
+drupal_prepare_form($form_id, $form, $form_state);
+// Store a copy of the unprocessed form for caching and indicate that it
+// is cacheable if #cache will be set.
+$original_form = $form;
+$cacheable = TRUE;
+unset($form_state['post']);
+}
+$form['#post'] = $_POST;
+// 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, $form_state);
+if ($cacheable && !empty($form['#cache'])) {
+// Caching is done past drupal_process_form so #process callbacks can
+// set #cache. By not sending the form state, we avoid storing
+// $form_state['storage'].
+form_set_cache($form_build_id, $original_form, NULL);
+}
+}
+// 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['storage'] or $form_state['rebuild'] have been
+// set by any submit or validate handlers, however, we know that
+// we're in a complex 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 $form_state in addition to any
+// other variables passed into drupal_get_form().
+if (!empty($form_state['rebuild']) || !empty($form_state['storage'])) {
+$form = drupal_rebuild_form($form_id, $form_state, $args);
+}
+// If we haven't redirected to a new location by now, we want to
+// render whatever form array is currently in hand.
+return drupal_render_form($form_id, $form);
+}
+/**
+* Retrieves a form, caches it and processes it with an empty $_POST.
+*
+* This function clears $_POST and passes the empty $_POST to the form_builder.
+* To preserve some parts from $_POST, pass them in $form_state.
+*
+* 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. Most
+*   important is the $form_state['storage'] collection.
+* @param $args
+*   Any additional arguments are passed on to the functions called by
+*   drupal_get_form(), plus the original form_state in the beginning. If you
+*   are getting a form from the cache, use $form['#parameters'] to shift off
+*   the $form_id from its beginning then the resulting array can be used as
+*   $arg here.
+* @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, $args, $form_build_id = NULL) {
+// Remove the first argument. This is $form_id.when called from
+// drupal_get_form and the original $form_state when called from some AHAH
+// callback. Neither is needed. After that, put in the current state.
+$args[0] = &$form_state;
+// And the form_id.
+array_unshift($args, $form_id);
+$form = call_user_func_array('drupal_retrieve_form', $args);
+if (!isset($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);
+// Now, we cache the form structure so it can be retrieved later for
+// validation. If $form_state['storage'] is populated, we'll also cache
+// it so that it can be used to resume complex multi-step processes.
+form_set_cache($form_build_id, $form, $form_state);
+// Clear out all post data, as we don't want the previous step's
+// data to pollute this one and trigger validate/submit handling,
+// then process the form for rendering.
+$_POST = array();
+$form['#post'] = array();
+drupal_process_form($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 = $cached->data;
+if ($cached = cache_get('storage_'. $form_build_id, 'cache_form')) {
+$form_state['storage'] = $cached->data;
+}
+return $form;
+}
+}
+/**
+* Store a form in the cache
+*/
+function form_set_cache($form_build_id, $form, $form_state) {
+$expire = max(ini_get('session.cookie_lifetime'), 86400);
+cache_set('form_'. $form_build_id, $form, 'cache_form', $expire);
+if (!empty($form_state['storage'])) {
+cache_set('storage_'. $form_build_id, $form_state['storage'], 'cache_form', $expire);
+}
+}
+/**
+* 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.
+* @param ...
+*   Any additional arguments are passed on to the functions called by
+*   drupal_execute(), 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:
+*
+* // register a new user
+* $form_state = array();
+* $form_state['values']['name'] = 'robo-user';
+* $form_state['values']['mail'] = 'robouser@example.com';
+* $form_state['values']['pass'] = 'password';
+* $form_state['values']['op'] = t('Create new account');
+* drupal_execute('user_register', $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_execute('story_node_form', $form_state, (object)$node);
+*/
+function drupal_execute($form_id, &$form_state) {
+$args = func_get_args();
+$form = call_user_func_array('drupal_retrieve_form', $args);
+$form['#post'] = $form_state['values'];
+drupal_prepare_form($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 $form_state
+*   A keyed array containing the current state of the form.
+* @param ...
+*   Any additional arguments needed by the unique form constructor
+*   function. Generally, these are any arguments passed into the
+*   drupal_get_form() or drupal_execute() functions after the first
+*   argument. If a module implements hook_forms(), it can examine
+*   these additional arguments and conditionally return different
+*   builder functions as well.
+*/
+function drupal_retrieve_form($form_id, &$form_state) {
+static $forms;
+// 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. We shift out the first argument -- the
+// $form_id itself -- from the list to pass into the constructor function,
+// since it's already known.
+$args = func_get_args();
+$saved_args = $args;
+array_shift($args);
+if (isset($form_state)) {
+array_shift($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 = $form_definition['callback'];
+}
+}
+array_unshift($args, NULL);
+$args[0] = &$form_state;
+// 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);
+// We store the original function arguments, rather than the final $arg
+// value, so that form_alter functions can see what was originally
+// passed to drupal_retrieve_form(). This allows the contents of #parameters
+// to be saved and passed in at a later date to recreate the form.
+$form['#parameters'] = $saved_args;
+return $form;
+}
+/**
+* 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) {
+$form_state['values'] = array();
+$form = form_builder($form_id, $form, $form_state);
+// Only process the form if it is programmed or the form_id coming
+// from the POST data is set and matches the current form_id.
+if ((!empty($form['#programmed'])) || (!empty($form['#post']) && (isset($form['#post']['form_id']) && ($form['#post']['form_id'] == $form_id)))) {
+drupal_validate_form($form_id, $form, $form_state);
+// form_clean_id() maintains a cache of element IDs it has seen,
+// so it can prevent duplicates. We want to be sure we reset that
+// cache when a form is processed, so scenerios that result in
+// the form being built behind the scenes and again for the
+// browser don't increment all the element IDs needlessly.
+form_clean_id(NULL, TRUE);
+if ((!empty($form_state['submitted'])) && !form_get_errors() && empty($form_state['rebuild'])) {
+$form_state['redirect'] = NULL;
+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_'. $form_state['values']['form_build_id'], 'cache_form');
+}
+// If batches were set in the submit handlers, we process them now,
+// possibly ending execution. We make sure we do not react to the batch
+// that is already being processed (if a batch operation performs a
+// drupal_execute).
+if ($batch =& batch_get() && !isset($batch['current_set'])) {
+// The batch uses its own copies of $form and $form_state for
+// late execution of submit handers and post-batch redirection.
+$batch['form'] = $form;
+$batch['form_state'] = $form_state;
+$batch['progressive'] = !$form['#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.
+}
+// If no submit handlers have populated the $form_state['storage']
+// bundle, and the $form_state['rebuild'] flag has not been set,
+// we're finished and should redirect to a new destination page
+// if one has been set (and a fresh, unpopulated copy of the form
+// if one hasn't). If the form was called by drupal_execute(),
+// however, we'll skip this and let the calling function examine
+// the resulting $form_state bundle itself.
+if (!$form['#programmed'] && empty($form_state['rebuild']) && empty($form_state['storage'])) {
+drupal_redirect_form($form, $form_state['redirect']);
+}
+}
+}
+}
+/**
+* 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';
+$form['#programmed'] = isset($form['#post']);
+if (isset($form['#build_id'])) {
+$form['form_build_id'] = array(
+'#type' => 'hidden',
+'#value' => $form['#build_id'],
+'#id' => $form['#build_id'],
+'#name' => 'form_build_id',
+);
+}
+// Add a token, based on either #token or form_id, to any form displayed to
+// authenticated users. This ensures that any submitted form was actually
+// requested previously by the user and protects against cross site request
+// forgeries.
+if (isset($form['#token'])) {
+if ($form['#token'] === FALSE || $user->uid == 0 || $form['#programmed']) {
+unset($form['#token']);
+}
+else {
+$form['form_token'] = array('#type' => 'token', '#default_value' => drupal_get_token($form['#token']));
+}
+}
+else if (isset($user->uid) && $user->uid && !$form['#programmed']) {
+$form['#token'] = $form_id;
+$form['form_token'] = array(
+'#id' => form_clean_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' => $form_id,
+'#id' => form_clean_id("edit-$form_id"),
+);
+}
+if (!isset($form['#id'])) {
+$form['#id'] = form_clean_id($form_id);
+}
+$form += _element_info('form');
+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');
+}
+}
+// Normally, we would call drupal_alter($form_id, $form, $form_state).
+// However, drupal_alter() normally supports just one byref parameter. Using
+// the __drupal_alter_by_ref key, we can store any additional parameters
+// that need to be altered, and they'll be split out into additional params
+// for the hook_form_alter() implementations.
+// @todo: Remove this in Drupal 7.
+$data = &$form;
+$data['__drupal_alter_by_ref'] = array(&$form_state);
+drupal_alter('form_'. $form_id, $data);
+// __drupal_alter_by_ref is unset in the drupal_alter() function, we need
+// to repopulate it to ensure both calls get the data.
+$data['__drupal_alter_by_ref'] = array(&$form_state);
+drupal_alter('form', $data, $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.
+* @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_submision'] = $data;
+*   This technique is useful when validation requires file parsing,
+*   web service requests, or other expensive requests that should
+*   not be repeated in the submission step.
+*/
+function drupal_validate_form($form_id, $form, &$form_state) {
+static $validated_forms = array();
+if (isset($validated_forms[$form_id])) {
+return;
+}
+// If the session token was set by drupal_prepare_form(), ensure that it
+// matches the current user's session.
+if (isset($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;
+}
+/**
+* Renders a structured form array into themed HTML.
+*
+* @param $form_id
+*   A unique string identifying the form for validation, submission,
+*   theming, and hook_form_alter functions.
+* @param $form
+*   An associative array containing the structure of the form.
+* @return
+*   A string containing the path of the page to display when processing
+*   is complete.
+*/
+function drupal_render_form($form_id, &$form) {
+// Don't override #theme if someone already set it.
+if (!isset($form['#theme'])) {
+init_theme();
+$registry = theme_get_registry();
+if (isset($registry[$form_id])) {
+$form['#theme'] = $form_id;
+}
+}
+$output = drupal_render($form);
+return $output;
+}
+/**
+* Redirect the user to a URL after a form has been processed.
+*
+* @param $form
+*   An associative array containing the structure of the form.
+* @param $redirect
+*   An optional value containing the destination path to redirect
+*   to if none is specified by the form.
+*/
+function drupal_redirect_form($form, $redirect = NULL) {
+$goto = NULL;
+if (isset($redirect)) {
+$goto = $redirect;
+}
+if ($goto !== FALSE && isset($form['#redirect'])) {
+$goto = $form['#redirect'];
+}
+if (!isset($goto) || ($goto !== FALSE)) {
+if (isset($goto)) {
+if (is_array($goto)) {
+call_user_func_array('drupal_goto', $goto);
+}
+else {
+drupal_goto($goto);
+}
+}
+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_submision'] = $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) {
+static $complete_form;
+// Also used in the installer, pre-database setup.
+$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']) || !$elements['#validated']) {
+if (isset($elements['#needs_validation'])) {
+// 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.
+if ($elements['#required'] && (!count($elements['#value']) || (is_string($elements['#value']) && strlen(trim($elements['#value'])) == 0))) {
+form_error($elements, $t('!name field is required.', array('!name' => $elements['#title'])));
+}
+// Verify that the value is not longer than #maxlength.
+if (isset($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] : $elements['#title']), WATCHDOG_ERROR);
+}
+}
+}
+// Call user-defined form level validators and store a copy of the full
+// form so that element-specific validators can examine the entire structure
+// if necessary.
+if (isset($form_id)) {
+form_execute_handlers('validate', $elements, $form_state);
+$complete_form = $elements;
+}
+// Call any element-specific validators. These must act on the element
+// #value data.
+elseif (isset($elements['#element_validate'])) {
+foreach ($elements['#element_validate'] as $function) {
+if (function_exists($function))  {
+$function($elements, $form_state, $complete_form);
+}
+}
+}
+$elements['#validated'] = TRUE;
+}
+}
+/**
+* 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) {
+$return = FALSE;
+if (isset($form_state[$type .'_handlers'])) {
+$handlers = $form_state[$type .'_handlers'];
+}
+elseif (isset($form['#'. $type])) {
+$handlers = $form['#'. $type];
+}
+else {
+$handlers = array();
+}
+foreach ($handlers as $function) {
+if (function_exists($function))  {
+if ($type == 'submit' && ($batch =& batch_get())) {
+// Some previous _submit handler has set a batch. We store the call
+// in a special 'control' batch set, for execution at the correct
+// time during the batch processing workflow.
+$batch['sets'][] = array('form_submit' => $function);
+}
+else {
+$function($form, $form_state);
+}
+$return = TRUE;
+}
+}
+return $return;
+}
+/**
+* File 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 $message
+*   The error message to present to the user.
+* @return
+*   Never use the return value of this function, use form_get_errors and
+*   form_get_error instead.
+*/
+function form_set_error($name = NULL, $message = '') {
+static $form = array();
+if (isset($name) && !isset($form[$name])) {
+$form[$name] = $message;
+if ($message) {
+drupal_set_message($message, 'error');
+}
+}
+return $form;
+}
+/**
+* Return an associative array of all errors.
+*/
+function form_get_errors() {
+$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 $_POST
+* data to the proper elements.
+*
+* @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. 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, $form, &$form_state) {
+static $complete_form, $cache;
+// Initialize as unprocessed.
+$form['#processed'] = FALSE;
+// Use element defaults.
+if ((!empty($form['#type'])) && ($info = _element_info($form['#type']))) {
+// Overlay $info onto $form, retaining preexisting keys in $form.
+$form += $info;
+}
+if (isset($form['#type']) && $form['#type'] == 'form') {
+$cache = NULL;
+$complete_form = $form;
+if (!empty($form['#programmed'])) {
+$form_state['submitted'] = TRUE;
+}
+}
+if (isset($form['#input']) && $form['#input']) {
+_form_builder_handle_input_element($form_id, $form, $form_state, $complete_form);
+}
+$form['#defaults_loaded'] = TRUE;
+// We start off assuming all form elements are in the correct order.
+$form['#sorted'] = TRUE;
+// Recurse through all child elements.
+$count = 0;
+foreach (element_children($form) as $key) {
+$form[$key]['#post'] = $form['#post'];
+$form[$key]['#programmed'] = $form['#programmed'];
+// Don't squash an existing tree value.
+if (!isset($form[$key]['#tree'])) {
+$form[$key]['#tree'] = $form['#tree'];
+}
+// Deny access to child elements if parent is denied.
+if (isset($form['#access']) && !$form['#access']) {
+$form[$key]['#access'] = FALSE;
+}
+// Don't squash existing parents value.
+if (!isset($form[$key]['#parents'])) {
+// Check to see if a tree of child elements is present. If so,
+// continue down the tree if required.
+$form[$key]['#parents'] = $form[$key]['#tree'] && $form['#tree'] ? array_merge($form['#parents'], array($key)) : array($key);
+$array_parents = isset($form['#array_parents']) ? $form['#array_parents'] : array();
+$array_parents[] = $key;
+$form[$key]['#array_parents'] = $array_parents;
+}
+// Assign a decimal placeholder weight to preserve original array order.
+if (!isset($form[$key]['#weight'])) {
+$form[$key]['#weight'] = $count/1000;
+}
+else {
+// If one of the child elements has a weight then we will need to sort
+// later.
+unset($form['#sorted']);
+}
+$form[$key] = form_builder($form_id, $form[$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($form['#after_build']) && !isset($form['#after_build_done'])) {
+foreach ($form['#after_build'] as $function) {
+$form = $function($form, $form_state);
+$form['#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($form, $form_state);
+// We shoud keep the buttons array until the IE clean up function
+// has recognized the submit button so the form has been marked
+// as submitted. If we already know which button was submitted,
+// we don't need the array.
+if (!empty($form_state['submitted'])) {
+unset($form_state['buttons']);
+}
+// If some callback set #cache, we need to flip a static flag so later it
+// can be found.
+if (isset($form['#cache'])) {
+$cache = $form['#cache'];
+}
+// We are on the top form, we can copy back #cache if it's set.
+if (isset($form['#type']) && $form['#type'] == 'form' && isset($cache)) {
+$form['#cache'] = TRUE;
+}
+return $form;
+}
+/**
+* Populate the #value and #name properties of input elements so they
+* can be processed and rendered. Also, execute any #process handlers
+* attached to a specific element.
+*/
+function _form_builder_handle_input_element($form_id, &$form, &$form_state, $complete_form) {
+if (!isset($form['#name'])) {
+$name = array_shift($form['#parents']);
+$form['#name'] = $name;
+if ($form['#type'] == 'file') {
+// To make it easier to handle $_FILES in file.inc, we place all
+// file fields in the 'files' array. Also, we do not support
+// nested file names.
+$form['#name'] = 'files['. $form['#name'] .']';
+}
+elseif (count($form['#parents'])) {
+$form['#name'] .= '['. implode('][', $form['#parents']) .']';
+}
+array_unshift($form['#parents'], $name);
+}
+if (!isset($form['#id'])) {
+$form['#id'] = form_clean_id('edit-'. implode('-', $form['#parents']));
+}
+unset($edit);
+if (!empty($form['#disabled'])) {
+$form['#attributes']['disabled'] = 'disabled';
+}
+if (!isset($form['#value']) && !array_key_exists('#value', $form)) {
+$function = !empty($form['#value_callback']) ? $form['#value_callback'] : 'form_type_'. $form['#type'] .'_value';
+if (($form['#programmed']) || ((!isset($form['#access']) || $form['#access']) && isset($form['#post']) && (isset($form['#post']['form_id']) && $form['#post']['form_id'] == $form_id))) {
+$edit = $form['#post'];
+foreach ($form['#parents'] as $parent) {
+$edit = isset($edit[$parent]) ? $edit[$parent] : NULL;
+}
+if (!$form['#programmed'] || isset($edit)) {
+// Call #type_value to set the form value;
+if (function_exists($function)) {
+$form['#value'] = $function($form, $edit);
+}
+if (!isset($form['#value']) && isset($edit)) {
+$form['#value'] = $edit;
+}
+}
+// Mark all posted values for validation.
+if (isset($form['#value']) || (isset($form['#required']) && $form['#required'])) {
+$form['#needs_validation'] = TRUE;
+}
+}
+// Load defaults.
+if (!isset($form['#value'])) {
+// Call #type_value without a second argument to request default_value handling.
+if (function_exists($function)) {
+$form['#value'] = $function($form);
+}
+// 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($form['#value']) && empty($form['#has_garbage_value'])) {
+$form['#value'] = isset($form['#default_value']) ? $form['#default_value'] : '';
+}
+}
+}
+// Determine which button (if any) was clicked to submit the form.
+// We compare the incoming values with the buttons defined in the form,
+// and flag the one that matches. We have to do some funky tricks to
+// deal with Internet Explorer's handling of single-button forms, though.
+if (!empty($form['#post']) && isset($form['#executes_submit_callback'])) {
+// First, accumulate a collection of buttons, divided into two bins:
+// those that execute full submit callbacks and those that only validate.
+$button_type = $form['#executes_submit_callback'] ? 'submit' : 'button';
+$form_state['buttons'][$button_type][] = $form;
+if (_form_button_was_clicked($form)) {
+$form_state['submitted'] = $form_state['submitted'] || $form['#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'][$form['#name']] = $form['#value'];
+$form_state['clicked_button'] = $form;
+if (isset($form['#validate'])) {
+$form_state['validate_handlers'] = $form['#validate'];
+}
+if (isset($form['#submit'])) {
+$form_state['submit_handlers'] = $form['#submit'];
+}
+}
+}
+// Allow for elements to expand to multiple elements, e.g., radios,
+// checkboxes and files.
+if (isset($form['#process']) && !$form['#processed']) {
+foreach ($form['#process'] as $process) {
+if (function_exists($process)) {
+$form = $process($form, isset($edit) ? $edit : NULL, $form_state, $complete_form);
+}
+}
+$form['#processed'] = TRUE;
+}
+form_set_value($form, $form['#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) {
+// 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['#post'][$form['#name']]) && $form['#post'][$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;
+}
+}
+}
+/**
+* Helper function to determine the value for an image button form element.
+*
+* @param $form
+*   The form element whose value is being populated.
+* @param $edit
+*   The incoming POST data 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 $form_state['values'] collection
+*   for this element. Return nothing to use the default.
+*/
+function form_type_image_button_value($form, $edit = FALSE) {
+if ($edit !== FALSE) {
+if (!empty($edit)) {
+// 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 $form['#return_value'];
+}
+else {
+// Unfortunately, in IE we never get back a proper value for THIS
+// form element. Instead, we get back two split values: one for the
+// X and one for the Y coordinates on which the user clicked the
+// button. We'll find this element in the #post data, and search
+// in the same spot for its name, with '_x'.
+$post = $form['#post'];
+foreach (split('\[', $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($post[$element_name])) {
+if (isset($post[$element_name .'_x'])) {
+return $form['#return_value'];
+}
+return NULL;
+}
+$post = $post[$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 $edit
+*   The incoming POST data 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 $form_state['values'] collection
+*   for this element. Return nothing to use the default.
+*/
+function form_type_checkbox_value($form, $edit = FALSE) {
+if ($edit !== FALSE) {
+return !empty($edit) ? $form['#return_value'] : 0;
+}
+}
+/**
+* Helper function to determine the value for a checkboxes form element.
+*
+* @param $form
+*   The form element whose value is being populated.
+* @param $edit
+*   The incoming POST data 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 $form_state['values'] collection
+*   for this element. Return nothing to use the default.
+*/
+function form_type_checkboxes_value($form, $edit = FALSE) {
+if ($edit === FALSE) {
+$value = array();
+$form += array('#default_value' => array());
+foreach ($form['#default_value'] as $key) {
+$value[$key] = 1;
+}
+return $value;
+}
+elseif (!isset($edit)) {
+return array();
+}
+}
+/**
+* Helper function to determine the value for a password_confirm form
+* element.
+*
+* @param $form
+*   The form element whose value is being populated.
+* @param $edit
+*   The incoming POST data 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 $form_state['values'] collection
+*   for this element. Return nothing to use the default.
+*/
+function form_type_password_confirm_value($form, $edit = FALSE) {
+if ($edit === FALSE) {
+$form += array('#default_value' => array());
+return $form['#default_value'] + array('pass1' => '', 'pass2' => '');
+}
+}
+/**
+* Helper function to determine the value for a select form element.
+*
+* @param $form
+*   The form element whose value is being populated.
+* @param $edit
+*   The incoming POST data 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 $form_state['values'] collection
+*   for this element. Return nothing to use the default.
+*/
+function form_type_select_value($form, $edit = FALSE) {
+if ($edit !== FALSE) {
+if (isset($form['#multiple']) && $form['#multiple']) {
+return (is_array($edit)) ? drupal_map_assoc($edit) : array();
+}
+else {
+return $edit;
+}
+}
+}
+/**
+* Helper function to determine the value for a textfield form element.
+*
+* @param $form
+*   The form element whose value is being populated.
+* @param $edit
+*   The incoming POST data 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 $form_state['values'] collection
+*   for this element. Return nothing to use the default.
+*/
+function form_type_textfield_value($form, $edit = FALSE) {
+if ($edit !== FALSE) {
+// Equate $edit to the form value to ensure it's marked for
+// validation.
+return str_replace(array("\r", "\n"), '', $edit);
+}
+}
+/**
+* Helper function to determine the value for form's token value.
+*
+* @param $form
+*   The form element whose value is being populated.
+* @param $edit
+*   The incoming POST data 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 $form_state['values'] collection
+*   for this element. Return nothing to use the default.
+*/
+function form_type_token_value($form, $edit = FALSE) {
+if ($edit !== FALSE) {
+return (string)$edit;
+}
+}
+/**
+* Use this function to make changes to form values in the form validate
+* phase, so they will be available in the submit phase in $form_state.
+*
+* Specifically, if $form['#parents'] is array('foo', 'bar')
+* and $value is 'baz' then this function will make
+* $form_state['values']['foo']['bar'] to be 'baz'.
+*
+* @param $form
+*   The form item. Keys used: #parents, #value
+* @param $value
+*   The value for the form item.
+*/
+function form_set_value($form, $value, &$form_state) {
+_form_set_value($form_state['values'], $form, $form['#parents'], $value);
+}
+/**
+* Helper function for form_set_value().
+*
+* We iterate over $parents and create nested arrays for them
+* in $form_state['values'] if needed. Then we insert the value into
+* the right array.
+*/
+function _form_set_value(&$form_values, $form, $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], $form, $parents, $value);
+}
+}
+/**
+* Retrieve the default properties for the defined element type.
+*/
+function _element_info($type, $refresh = NULL) {
+static $cache;
+$basic_defaults = array(
+'#description' => NULL,
+'#attributes' => array(),
+'#required' => FALSE,
+'#tree' => FALSE,
+'#parents' => array()
+);
+if (!isset($cache) || $refresh) {
+$cache = array();
+foreach (module_implements('elements') as $module) {
+$elements = module_invoke($module, 'elements');
+if (isset($elements) && is_array($elements)) {
+$cache = array_merge_recursive($cache, $elements);
+}
+}
+if (sizeof($cache)) {
+foreach ($cache as $element_type => $info) {
+$cache[$element_type] = array_merge_recursive($basic_defaults, $info);
+}
+}
+}
+return $cache[$type];
+}
+function form_options_flatten($array, $reset = TRUE) {
+static $return;
+if ($reset) {
+$return = array();
+}
+foreach ($array as $key => $value) {
+if (is_object($value)) {
+form_options_flatten($value->option, FALSE);
+}
+else if (is_array($value)) {
+form_options_flatten($value, FALSE);
+}
+else {
+$return[$key] = 1;
+}
+}
+return $return;
+}
+/**
+* Format a dropdown menu or scrolling selection box.
+*
+* @param $element
+*   An associative array containing the properties of the element.
+*   Properties used: title, value, options, description, extra, multiple, required
+* @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 $options format.
+*/
+function theme_select($element) {
+$select = '';
+$size = $element['#size'] ? ' size="'. $element['#size'] .'"' : '';
+_form_set_class($element, array('form-select'));
+$multiple = $element['#multiple'];
+return theme('form_element', $element, '<select name="'. $element['#name'] .''. ($multiple ? '[]' : '') .'"'. ($multiple ? ' multiple="multiple" ' : '') . drupal_attributes($element['#attributes']) .' id="'. $element['#id'] .'" '. $size .'>'. form_select_options($element) .'</select>');
+}
+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;
+}
+else if (is_object($choice)) {
+if (isset($choice->option[$key])) {
+$keys[] = $index;
+}
+}
+else if ($index == $key) {
+$keys[] = $index;
+}
+}
+return $keys;
+}
+/**
+* Format a group of form items.
+*
+* @param $element
+*   An associative array containing the properties of the element.
+*   Properties used: attributes, title, value, description, children, collapsible, collapsed
+* @return
+*   A themed HTML string representing the form item group.
+*
+* @ingroup themeable
+*/
+function theme_fieldset($element) {
+if ($element['#collapsible']) {
+drupal_add_js('misc/collapse.js');
+if (!isset($element['#attributes']['class'])) {
+$element['#attributes']['class'] = '';
+}
+$element['#attributes']['class'] .= ' collapsible';
+if ($element['#collapsed']) {
+$element['#attributes']['class'] .= ' collapsed';
+}
+}
+return '<fieldset'. drupal_attributes($element['#attributes']) .'>'. ($element['#title'] ? '<legend>'. $element['#title'] .'</legend>' : '') . (isset($element['#description']) && $element['#description'] ? '<div class="description">'. $element['#description'] .'</div>' : '') . (!empty($element['#children']) ? $element['#children'] : '') . $element['#value'] ."</fieldset>\n";
+}
+/**
+* Format a radio button.
+*
+* @param $element
+*   An associative array containing the properties of the element.
+*   Properties used: required, return_value, value, attributes, title, description
+* @return
+*   A themed HTML string representing the form item group.
+*
+* @ingroup themeable
+*/
+function theme_radio($element) {
+_form_set_class($element, array('form-radio'));
+$output = '<input type="radio" ';
+$output .= 'name="'. $element['#name'] .'" ';
+$output .= 'value="'. $element['#return_value'] .'" ';
+$output .= (check_plain($element['#value']) == $element['#return_value']) ? ' checked="checked" ' : ' ';
+$output .= drupal_attributes($element['#attributes']) .' />';
+if (!is_null($element['#title'])) {
+$output = '<label class="option">'. $output .' '. $element['#title'] .'</label>';
+}
+unset($element['#title']);
+return theme('form_element', $element, $output);
+}
+/**
+* Format a set of radio buttons.
+*
+* @param $element
+*   An associative array containing the properties of the element.
+*   Properties used: title, value, options, description, required and attributes.
+* @return
+*   A themed HTML string representing the radio button set.
+*
+* @ingroup themeable
+*/
+function theme_radios($element) {
+$class = 'form-radios';
+if (isset($element['#attributes']['class'])) {
+$class .= ' '. $element['#attributes']['class'];
+}
+$element['#children'] = '<div class="'. $class .'">'. (!empty($element['#children']) ? $element['#children'] : '') .'</div>';
+if ($element['#title'] || $element['#description']) {
+unset($element['#id']);
+return theme('form_element', $element, $element['#children']);
+}
+else {
+return $element['#children'];
+}
+}
+/**
+* Format a password_confirm item.
+*
+* @param $element
+*   An associative array containing the properties of the element.
+*   Properties used: title, value, id, required, error.
+* @return
+*   A themed HTML string representing the form item.
+*
+* @ingroup themeable
+*/
+function theme_password_confirm($element) {
+return theme('form_element', $element, $element['#children']);
+}
+/**
+* Expand a password_confirm field into two text boxes.
+*/
+function expand_password_confirm($element) {
+$element['pass1'] =  array(
+'#type' => 'password',
+'#title' => t('Password'),
+'#value' => empty($element['#value']) ? NULL : $element['#value']['pass1'],
+'#required' => $element['#required'],
+'#attributes' => array('class' => 'password-field'),
+);
+$element['pass2'] =  array(
+'#type' => 'password',
+'#title' => t('Confirm password'),
+'#value' => empty($element['#value']) ? NULL : $element['#value']['pass2'],
+'#required' => $element['#required'],
+'#attributes' => array('class' => 'password-confirm'),
+);
+$element['#element_validate'] = array('password_confirm_validate');
+$element['#tree'] = TRUE;
+if (isset($element['#size'])) {
+$element['pass1']['#size'] = $element['pass2']['#size'] = $element['#size'];
+}
+return $element;
+}
+/**
+* Validate password_confirm element.
+*/
+function password_confirm_validate($form, &$form_state) {
+$pass1 = trim($form['pass1']['#value']);
+if (!empty($pass1)) {
+$pass2 = trim($form['pass2']['#value']);
+if ($pass1 != $pass2) {
+form_error($form, t('The specified passwords do not match.'));
+}
+}
+elseif ($form['#required'] && !empty($form['#post'])) {
+form_error($form, t('Password field is required.'));
+}
+// Password field must be converted from a two-element array into a single
+// string regardless of validation results.
+form_set_value($form['pass1'], NULL, $form_state);
+form_set_value($form['pass2'], NULL, $form_state);
+form_set_value($form, $pass1, $form_state);
+return $form;
+}
+/**
+* Format a date selection element.
+*
+* @param $element
+*   An associative array containing the properties of the element.
+*   Properties used: title, value, options, description, required and attributes.
+* @return
+*   A themed HTML string representing the date selection boxes.
+*
+* @ingroup themeable
+*/
+function theme_date($element) {
+return theme('form_element', $element, '<div class="container-inline">'. $element['#children'] .'</div>');
+}
+/**
+* Roll out a single date element.
+*/
+function expand_date($element) {
+// Default to current date
+if (empty($element['#value'])) {
+$element['#value'] = array('day' => format_date(time(), 'custom', 'j'),
+'month' => format_date(time(), 'custom', 'n'),
+'year' => format_date(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':
+$options = drupal_map_assoc(range(1900, 2050));
+break;
+}
+$parents = $element['#parents'];
+$parents[] = $type;
+$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) {
+return format_date(gmmktime(0, 0, 0, $month, 2, 1970), 'custom', 'M', 0);
+}
+/**
+* If no default value is set for weight select boxes, use 0.
+*/
+function weight_value(&$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 expand_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' => form_clean_id('edit-'. implode('-', $parents_for_id)),
+);
+}
+}
+}
+return $element;
+}
+/**
+* Add AHAH information about a form element to the page to communicate with
+* javascript. If #ahah[path] is set on an element, this additional javascript is
+* added to the page header to attach the AHAH behaviors. See ahah.js for more
+* information.
+*
+* @param $element
+*   An associative array containing the properties of the element.
+*   Properties used: ahah_event, ahah_path, ahah_wrapper, ahah_parameters,
+*   ahah_effect.
+* @return
+*   None. Additional code is added to the header of the page using
+*   drupal_add_js.
+*/
+function form_expand_ahah($element) {
+static $js_added = array();
+// Add a reasonable default event handler if none specified.
+if (isset($element['#ahah']['path']) && !isset($element['#ahah']['event'])) {
+switch ($element['#type']) {
+case 'submit':
+case 'button':
+case 'image_button':
+// Use the mousedown instead of the click event because form
+// submission via pressing the enter key triggers a click event on
+// submit inputs, inappropriately triggering AHAH behaviors.
+$element['#ahah']['event'] = 'mousedown';
+// Attach an additional event handler so that AHAH behaviours
+// can be triggered still via keyboard input.
+$element['#ahah']['keypress'] = TRUE;
+break;
+case 'password':
+case 'textfield':
+case 'textarea':
+$element['#ahah']['event'] = 'blur';
+break;
+case 'radio':
+case 'checkbox':
+case 'select':
+$element['#ahah']['event'] = 'change';
+break;
+}
+}
+// Adding the same javascript settings twice will cause a recursion error,
+// we avoid the problem by checking if the javascript has already been added.
+if (isset($element['#ahah']['path']) && isset($element['#ahah']['event']) && !isset($js_added[$element['#id']])) {
+drupal_add_js('misc/jquery.form.js');
+drupal_add_js('misc/ahah.js');
+$ahah_binding = array(
+'url'      => url($element['#ahah']['path']),
+'event'    => $element['#ahah']['event'],
+'keypress' => empty($element['#ahah']['keypress']) ? NULL : $element['#ahah']['keypress'],
+'wrapper'  => empty($element['#ahah']['wrapper']) ? NULL : $element['#ahah']['wrapper'],
+'selector' => empty($element['#ahah']['selector']) ? '#'. $element['#id'] : $element['#ahah']['selector'],
+'effect'   => empty($element['#ahah']['effect']) ? 'none' : $element['#ahah']['effect'],
+'method'   => empty($element['#ahah']['method']) ? 'replace' : $element['#ahah']['method'],
+'progress' => empty($element['#ahah']['progress']) ? array('type' => 'throbber') : $element['#ahah']['progress'],
+'button'   => isset($element['#executes_submit_callback']) ? array($element['#name'] => $element['#value']) : FALSE,
+);
+// Convert a simple #ahah[progress] type string into an array.
+if (is_string($ahah_binding['progress'])) {
+$ahah_binding['progress'] = array('type' => $ahah_binding['progress']);
+}
+// Change progress path to a full url.
+if (isset($ahah_binding['progress']['path'])) {
+$ahah_binding['progress']['url'] = url($ahah_binding['progress']['path']);
+}
+// Add progress.js if we're doing a bar display.
+if ($ahah_binding['progress']['type'] == 'bar') {
+drupal_add_js('misc/progress.js');
+}
+drupal_add_js(array('ahah' => array($element['#id'] => $ahah_binding)), 'setting');
+$js_added[$element['#id']] = TRUE;
+$element['#cache'] = TRUE;
+}
+return $element;
+}
+/**
+* Format a form item.
+*
+* @param $element
+*   An associative array containing the properties of the element.
+*   Properties used:  title, value, description, required, error
+* @return
+*   A themed HTML string representing the form item.
+*
+* @ingroup themeable
+*/
+function theme_item($element) {
+return theme('form_element', $element, $element['#value'] . (!empty($element['#children']) ? $element['#children'] : ''));
+}
+/**
+* Format a checkbox.
+*
+* @param $element
+*   An associative array containing the properties of the element.
+*   Properties used:  title, value, return_value, description, required
+* @return
+*   A themed HTML string representing the checkbox.
+*
+* @ingroup themeable
+*/
+function theme_checkbox($element) {
+_form_set_class($element, array('form-checkbox'));
+$checkbox = '<input ';
+$checkbox .= 'type="checkbox" ';
+$checkbox .= 'name="'. $element['#name'] .'" ';
+$checkbox .= 'id="'. $element['#id'] .'" ' ;
+$checkbox .= 'value="'. $element['#return_value'] .'" ';
+$checkbox .= $element['#value'] ? ' checked="checked" ' : ' ';
+$checkbox .= drupal_attributes($element['#attributes']) .' />';
+if (!is_null($element['#title'])) {
+$checkbox = '<label class="option">'. $checkbox .' '. $element['#title'] .'</label>';
+}
+unset($element['#title']);
+return theme('form_element', $element, $checkbox);
+}
+/**
+* Format a set of checkboxes.
+*
+* @param $element
+*   An associative array containing the properties of the element.
+* @return
+*   A themed HTML string representing the checkbox set.
+*
+* @ingroup themeable
+*/
+function theme_checkboxes($element) {
+$class = 'form-checkboxes';
+if (isset($element['#attributes']['class'])) {
+$class .= ' '. $element['#attributes']['class'];
+}
+$element['#children'] = '<div class="'. $class .'">'. (!empty($element['#children']) ? $element['#children'] : '') .'</div>';
+if ($element['#title'] || $element['#description']) {
+unset($element['#id']);
+return theme('form_element', $element, $element['#children']);
+}
+else {
+return $element['#children'];
+}
+}
+function expand_checkboxes($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]), '#attributes' => $element['#attributes']);
+}
+}
+}
+return $element;
+}
+/**
+* Theme a form submit button.
+*
+* @ingroup themeable
+*/
+function theme_submit($element) {
+return theme('button', $element);
+}
+/**
+* Theme a form button.
+*
+* @ingroup themeable
+*/
+function theme_button($element) {
+// Make sure not to overwrite classes.
+if (isset($element['#attributes']['class'])) {
+$element['#attributes']['class'] = 'form-'. $element['#button_type'] .' '. $element['#attributes']['class'];
+}
+else {
+$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($element['#attributes']) ." />\n";
+}
+/**
+* Theme a form image button.
+*
+* @ingroup themeable
+*/
+function theme_image_button($element) {
+// Make sure not to overwrite classes.
+if (isset($element['#attributes']['class'])) {
+$element['#attributes']['class'] = 'form-'. $element['#button_type'] .' '. $element['#attributes']['class'];
+}
+else {
+$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="'. base_path() . $element['#src'] .'" '.
+(!empty($element['#title']) ? 'alt="'. check_plain($element['#title']) .'" title="'. check_plain($element['#title']) .'" ' : '' ) .
+"/>\n";
+}
+/**
+* Format a hidden form field.
+*
+* @param $element
+*   An associative array containing the properties of the element.
+*   Properties used:  value, edit
+* @return
+*   A themed HTML string representing the hidden form field.
+*
+* @ingroup themeable
+*/
+function theme_hidden($element) {
+return '<input type="hidden" name="'. $element['#name'] .'" id="'. $element['#id'] .'" value="'. check_plain($element['#value']) ."\" ". drupal_attributes($element['#attributes']) ." />\n";
+}
+/**
+* Format a form token.
+*
+* @ingroup themeable
+*/
+function theme_token($element) {
+return theme('hidden', $element);
+}
+/**
+* Format a textfield.
+*
+* @param $element
+*   An associative array containing the properties of the element.
+*   Properties used:  title, value, description, size, maxlength, required, attributes autocomplete_path
+* @return
+*   A themed HTML string representing the textfield.
+*
+* @ingroup themeable
+*/
+function theme_textfield($element) {
+$size = empty($element['#size']) ? '' : ' size="'. $element['#size'] .'"';
+$maxlength = empty($element['#maxlength']) ? '' : ' maxlength="'. $element['#maxlength'] .'"';
+$class = array('form-text');
+$extra = '';
+$output = '';
+if ($element['#autocomplete_path']) {
+drupal_add_js('misc/autocomplete.js');
+$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 theme('form_element', $element, $output) . $extra;
+}
+/**
+* Format a form.
+*
+* @param $element
+*   An associative array containing the properties of the element.
+*   Properties used: action, method, attributes, children
+* @return
+*   A themed HTML string representing the form.
+*
+* @ingroup themeable
+*/
+function theme_form($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";
+}
+/**
+* Format a textarea.
+*
+* @param $element
+*   An associative array containing the properties of the element.
+*   Properties used: title, value, description, rows, cols, required, attributes
+* @return
+*   A themed HTML string representing the textarea.
+*
+* @ingroup themeable
+*/
+function theme_textarea($element) {
+$class = array('form-textarea');
+// Add teaser behavior (must come before resizable)
+if (!empty($element['#teaser'])) {
+drupal_add_js('misc/teaser.js');
+// Note: arrays are merged in drupal_get_js().
+drupal_add_js(array('teaserCheckbox' => array($element['#id'] => $element['#teaser_checkbox'])), 'setting');
+drupal_add_js(array('teaser' => array($element['#id'] => $element['#teaser'])), 'setting');
+$class[] = 'teaser';
+}
+// Add resizable behavior
+if ($element['#resizable'] !== FALSE) {
+drupal_add_js('misc/textarea.js');
+$class[] = 'resizable';
+}
+_form_set_class($element, $class);
+return theme('form_element', $element, '<textarea cols="'. $element['#cols'] .'" rows="'. $element['#rows'] .'" name="'. $element['#name'] .'" id="'. $element['#id'] .'" '. drupal_attributes($element['#attributes']) .'>'. check_plain($element['#value']) .'</textarea>');
+}
+/**
+* Format HTML markup for use in forms.
+*
+* This is used in more advanced forms, such as theme selection and filter format.
+*
+* @param $element
+*   An associative array containing the properties of the element.
+*   Properties used: value, children.
+* @return
+*   A themed HTML string representing the HTML markup.
+*
+* @ingroup themeable
+*/
+function theme_markup($element) {
+return (isset($element['#value']) ? $element['#value'] : '') . (isset($element['#children']) ? $element['#children'] : '');
+}
+/**
+* Format a password field.
+*
+* @param $element
+*   An associative array containing the properties of the element.
+*   Properties used:  title, value, description, size, maxlength, required, attributes
+* @return
+*   A themed HTML string representing the form.
+*
+* @ingroup themeable
+*/
+function theme_password($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 theme('form_element', $element, $output);
+}
+/**
+* Expand weight elements into selects.
+*/
+function process_weight($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;
+}
+/**
+* Format a file upload field.
+*
+* @param $title
+*   The label for the file upload field.
+* @param $name
+*   The internal name used to refer to the field.
+* @param $size
+*   A measure of the visible size of the field (passed directly to HTML).
+* @param $description
+*   Explanatory text to display after the form item.
+* @param $required
+*   Whether the user must upload a file to the field.
+* @return
+*   A themed HTML string representing the field.
+*
+* @ingroup themeable
+*
+* For assistance with handling the uploaded file correctly, see the API
+* provided by file.inc.
+*/
+function theme_file($element) {
+_form_set_class($element, array('form-file'));
+return theme('form_element', $element, '<input type="file" name="'. $element['#name'] .'"'. ($element['#attributes'] ? ' '. drupal_attributes($element['#attributes']) : '') .' id="'. $element['#id'] .'" size="'. $element['#size'] ."\" />\n");
+}
+/**
+* Return a themed form element.
+*
+* @param element
+*   An associative array containing the properties of the element.
+*   Properties used: title, description, id, required
+* @param $value
+*   The form element's data.
+* @return
+*   A string representing the form element.
+*
+* @ingroup themeable
+*/
+function theme_form_element($element, $value) {
+// This is also used in the installer, pre-database setup.
+$t = get_t();
+$output = '<div class="form-item"';
+if (!empty($element['#id'])) {
+$output .= ' id="'. $element['#id'] .'-wrapper"';
+}
+$output .= ">\n";
+$required = !empty($element['#required']) ? '<span class="form-required" title="'. $t('This field is required.') .'">*</span>' : '';
+if (!empty($element['#title'])) {
+$title = $element['#title'];
+if (!empty($element['#id'])) {
+$output .= ' <label for="'. $element['#id'] .'">'. $t('!title: !required', array('!title' => filter_xss_admin($title), '!required' => $required)) ."</label>\n";
+}
+else {
+$output .= ' <label>'. $t('!title: !required', array('!title' => filter_xss_admin($title), '!required' => $required)) ."</label>\n";
+}
+}
+$output .= " $value\n";
+if (!empty($element['#description'])) {
+$output .= ' <div class="description">'. $element['#description'] ."</div>\n";
+}
+$output .= "</div>\n";
+return $output;
+}
+/**
+* Sets a form element's class attribute.
+*
+* Adds 'required' and 'error' classes as needed.
+*
+* @param &$element
+*   The form element.
+* @param $name
+*   Array of new class names to be added.
+*/
+function _form_set_class(&$element, $class = array()) {
+if ($element['#required']) {
+$class[] = 'required';
+}
+if (form_get_error($element)) {
+$class[] = 'error';
+}
+if (isset($element['#attributes']['class'])) {
+$class[] = $element['#attributes']['class'];
+}
+$element['#attributes']['class'] = implode(' ', $class);
+}
+/**
+* Prepare an HTML ID attribute string for a form item.
+*
+* Remove invalid characters and guarantee uniqueness.
+*
+* @param $id
+*   The ID to clean.
+* @param $flush
+*   If set to TRUE, the function will flush and reset the static array
+*   which is built to test the uniqueness of element IDs. This is only
+*   used if a form has completed the validation process. This parameter
+*   should never be set to TRUE if this function is being called to
+*   assign an ID to the #ID element.
+* @return
+*   The cleaned ID.
+*/
+function form_clean_id($id = NULL, $flush = FALSE) {
+static $seen_ids = array();
+if ($flush) {
+$seen_ids = array();
+return;
+}
+$id = str_replace(array('][', '_', ' '), '-', $id);
+// Ensure IDs are unique. The first occurrence is held but left alone.
+// Subsequent occurrences get a number appended to them. This incrementing
+// will almost certainly break code that relies on explicit HTML IDs in
+// forms that appear more than once on the page, but the alternative is
+// outputting duplicate IDs, which would break JS code and XHTML
+// validity anyways. For now, it's an acceptable stopgap solution.
+if (isset($seen_ids[$id])) {
+$id = $id .'-'. $seen_ids[$id]++;
+}
+else {
+$seen_ids[$id] = 1;
+}
+return $id;
+}
+/**
+* @} 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',
+* );
+* batch_set($batch);
+* // only needed if not inside a form _submit handler :
+* batch_process();
+* @endcode
+*
+* Sample batch operations:
+* @code
+* // Simple and artificial: load a node of a given type for a given user
+* function my_function_1($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_result(db_query('SELECT COUNT(DISTINCT nid) FROM {node}'));
+*   }
+*   $limit = 5;
+*   $result = db_query_range("SELECT nid FROM {node} WHERE nid > %d ORDER BY nid ASC", $context['sandbox']['current_node'], 0, $limit);
+*   while ($row = db_fetch_array($result)) {
+*     $node = node_load($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
+*/
+/**
+* Open a new batch.
+*
+* @param $batch
+*   An array defining the batch. The following keys can be used:
+*     'operations': an array of function calls to be performed.
+*        Example:
+*        @code
+*        array(
+*          array('my_function_1', array($arg1)),
+*          array('my_function_2', array($arg2_1, $arg2_2)),
+*        )
+*        @endcode
+*     All the other values below are optional.
+*     batch_init() provides default values for the messages.
+*     'title': title for the progress page.
+*       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 and @percent.
+*       Defaults to t('Remaining @remaining of @total.').
+*     'error_message': message displayed if an error occurred while processing
+*       the batch.
+*       Defaults to t('An error has occurred.').
+*     'finished': the 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 $_SESSION for display after
+*       final page redirection.
+*     'file': the path to the file containing the definitions of the
+*       'operations' and 'finished' functions, for instance if they don't
+*       reside in the original '.module' file. The path should be relative to
+*       the base_path(), and thus should be built using drupal_get_path().
+*
+* Operations are added as new batch sets. Batch sets are used to ensure
+* clean code independence, ensuring that several batches submitted by
+* different parts of the code (core / contrib modules) can be processed
+* correctly while not interfering or having to cope with each other. Each
+* batch set gets to specify his own UI messages, operates on its own set
+* of operations and results, and triggers its own 'finished' callback.
+* Batch sets are processed sequentially, with the progress bar starting
+* fresh for every new set.
+*/
+function batch_set($batch_definition) {
+if ($batch_definition) {
+$batch =& batch_get();
+// Initialize the batch
+if (empty($batch)) {
+$batch = array(
+'sets' => array(),
+);
+}
+$init = array(
+'sandbox' => array(),
+'results' => array(),
+'success' => FALSE,
+);
+// Use get_t() to allow batches at install time.
+$t = get_t();
+$defaults = array(
+'title' => $t('Processing'),
+'init_message' => $t('Initializing.'),
+'progress_message' => $t('Remaining @remaining of @total.'),
+'error_message' => $t('An error has occurred.'),
+);
+$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;';
+$batch_set['total'] = count($batch_set['operations']);
+// If the batch is being processed (meaning we are executing a stored submit handler),
+// insert the new set after the current one.
+if (isset($batch['current_set'])) {
+// array_insert does not exist...
+$slice1 = array_slice($batch['sets'], 0, $batch['current_set'] + 1);
+$slice2 = array_slice($batch['sets'], $batch['current_set'] + 1);
+$batch['sets'] = array_merge($slice1, array($batch_set), $slice2);
+}
+else {
+$batch['sets'][] = $batch_set;
+}
+}
+}
+/**
+* Process 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 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 $url
+*   (optional - should only be used for separate scripts like update.php)
+*   URL of the batch processing page.
+*/
+function batch_process($redirect = NULL, $url = NULL) {
+$batch =& batch_get();
+if (isset($batch)) {
+// Add process information
+$url = isset($url) ? $url : 'batch';
+$process_info = array(
+'current_set' => 0,
+'progressive' => TRUE,
+'url' => isset($url) ? $url : 'batch',
+'source_page' => $_GET['q'],
+'redirect' => $redirect,
+);
+$batch += $process_info;
+if ($batch['progressive']) {
+// Clear the way for the drupal_goto redirection to the batch processing
+// page, by saving and unsetting the 'destination' if any, on both places
+// drupal_goto looks for it.
+if (isset($_REQUEST['destination'])) {
+$batch['destination'] = $_REQUEST['destination'];
+unset($_REQUEST['destination']);
+}
+elseif (isset($_REQUEST['edit']['destination'])) {
+$batch['destination'] = $_REQUEST['edit']['destination'];
+unset($_REQUEST['edit']['destination']);
+}
+// Initiate db storage in order to get a batch id. We have to provide
+// at least an empty string for the (not null) 'token' column.
+db_query("INSERT INTO {batch} (token, timestamp) VALUES ('', %d)", time());
+$batch['id'] = db_last_insert_id('batch', 'bid');
+// Now that we have a batch id, we can generate the redirection link in
+// the generic error message.
+$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' => $batch['id'], 'op' => 'finished')))));
+// Actually store the batch data and the token generated form the batch id.
+db_query("UPDATE {batch} SET token = '%s', batch = '%s' WHERE bid = %d", drupal_get_token($batch['id']), serialize($batch), $batch['id']);
+drupal_goto($batch['url'], 'op=start&id='. $batch['id']);
+}
+else {
+// Non-progressive execution: bypass the whole progressbar workflow
+// and execute the batch in one pass.
+require_once './includes/batch.inc';
+_batch_process();
+}
+}
+}
+/**
+* Retrieve the current batch.
+*/
+function &batch_get() {
+static $batch = array();
+return $batch;
+}
+/**
+* @} End of "defgroup batch".
+*/

Mercurial > defr > drupal > core

comparison includes/form.inc @ 1:c1f4ac30525a 6.0