drupal_retrieve_form
- Versions
- 5
drupal_retrieve_form($form_id)- 6 – 7
drupal_retrieve_form($form_id, &$form_state)
Retrieves the structured array that defines a given form.
Parameters
$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.
$form_state A keyed array containing the current state of the form.
... Any additional arguments needed by the unique form constructor function. Generally, these are any arguments passed into the drupal_get_form() or drupal_form_submit() functions after the first argument. If a module implements hook_forms(), it can examine these additional arguments and conditionally return different builder functions as well.
Related topics
Code
includes/form.inc, line 472
<?php
function drupal_retrieve_form($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;
}
?>