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<?php
/**
* @file
* Contains \Drupal\Core\Form\FormBuilderInterface.
*/
namespace Drupal\Core\Form;
/**
* Provides an interface for form building and processing.
*/
interface FormBuilderInterface {
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/**
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* Determines the ID of a form.
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*
* @param \Drupal\Core\Form\FormInterface|string $form_arg
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* The value is identical to that of self::getForm()'s $form_arg argument.
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* @param \Drupal\Core\Form\FormStateInterface $form_state
* The current state of the form.
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*
* @return string
* The unique string identifying the desired form.
*/
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public function getFormId($form_arg, FormStateInterface &$form_state);
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/**
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* Gets a renderable form array.
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*
* This function should be used instead of self::buildForm() when $form_state
* is not needed (i.e., when initially rendering the form) and is often
* used as a menu callback.
*
* @param \Drupal\Core\Form\FormInterface|string $form_arg
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* The value must be one of the following:
* - The name of a class that implements \Drupal\Core\Form\FormInterface.
* - An instance of a class that implements \Drupal\Core\Form\FormInterface.
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* @param ...
* Any additional arguments are passed on to the functions called by
* \Drupal::formBuilder()->getForm(), including the unique form constructor
* function. For example, the node_edit form requires that a node object is
* passed in here when it is called. These are available to implementations
* of hook_form_alter() and hook_form_FORM_ID_alter() as the array
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* $form_state['build_info']['args'].
*
* @return array
* The form array.
*
* @see \Drupal\Core\Form\FormBuilderInterface::buildForm()
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*/
public function getForm($form_arg);
/**
* Builds and processes a form for a given form ID.
*
* The form may also be retrieved from the cache if the form was built in a
* previous page-load. The form is then passed on for processing, validation
* and submission if there is proper input.
*
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* @param \Drupal\Core\Form\FormInterface|string $form_id
* The value must be one of the following:
* - The name of a class that implements \Drupal\Core\Form\FormInterface.
* - An instance of a class that implements \Drupal\Core\Form\FormInterface.
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* @param \Drupal\Core\Form\FormStateInterface $form_state
* The current state of the form.
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*
* @return array
* The rendered form. This function may also perform a redirect and hence
* may not return at all depending upon the $form_state flags that were set.
*
* @see self::redirectForm()
*/
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public function buildForm($form_id, FormStateInterface &$form_state);
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/**
* Constructs a new $form from the information in $form_state.
*
* This is the key function for making multi-step forms advance from step to
* step. It is called by self::processForm() when all user input processing,
* including calling validation and submission handlers, for the request is
* finished. If a validate or submit handler set $form_state['rebuild'] to
* TRUE, and if other conditions don't preempt a rebuild from happening, then
* this function is called to generate a new $form, the next step in the form
* workflow, to be returned for rendering.
*
* Ajax form submissions are almost always multi-step workflows, so that is
* one common use-case during which form rebuilding occurs. See
* Drupal\system\FormAjaxController::content() for more information about
* creating Ajax-enabled forms.
*
* @param string $form_id
* The unique string identifying the desired form. If a function with that
* name exists, it is called to build the form array.
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* @param \Drupal\Core\Form\FormStateInterface $form_state
* The current state of the form.
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* @param array|null $old_form
* (optional) A previously built $form. Used to retain the #build_id and
* #action properties in Ajax callbacks and similar partial form rebuilds.
* The only properties copied from $old_form are the ones which both exist
* in $old_form and for which $form_state['rebuild_info']['copy'][PROPERTY]
* is TRUE. If $old_form is not passed, the entire $form is rebuilt freshly.
* 'rebuild_info' needs to be a separate top-level property next to
* 'build_info', since the contained data must not be cached.
*
* @return array
* The newly built form.
*
* @see self::processForm()
* @see \Drupal\system\FormAjaxController::content()
*/
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public function rebuildForm($form_id, FormStateInterface &$form_state, $old_form = NULL);
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/**
* Fetches a form from the cache.
*/
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public function getCache($form_build_id, FormStateInterface &$form_state);
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/**
* Stores a form in the cache.
*/
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public function setCache($form_build_id, $form, FormStateInterface $form_state);
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/**
* Retrieves, populates, and processes a form.
*
* This function allows you to supply values for form elements and submit a
* form for processing. Compare to self::getForm(), which also builds and
* processes a form, but does not allow you to supply values.
*
* There is no return value, but you can check to see if there are errors
* by calling form_get_errors().
*
* @param \Drupal\Core\Form\FormInterface|string $form_arg
* A form object to use to build the form, or the unique string identifying
* the desired form. If $form_arg is a string and a function with that
* name exists, it is called to build the form array.
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* @param $form_state
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* The current state of the form. Most important is the
* $form_state['values'] collection, a tree of data used to simulate the
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* incoming \Drupal::request()->request information from a user's form
* submission. If a key is not filled in $form_state['values'], then the
* default value of the respective element is used. To submit an unchecked
* checkbox or other control that browsers submit by not having a
* \Drupal::request()->request entry, include the key, but set the value to
* NULL.
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* @param ...
* Any additional arguments are passed on to the functions called by
* self::submitForm(), 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. Arguments that need to be passed by reference
* should not be included here, but rather placed directly in the
* $form_state build info array so that the reference can be preserved. For
* example, a form builder function with the following signature:
* @code
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* function mymodule_form($form, FormStateInterface &$form_state, &$object) {
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* }
* @endcode
* would be called via self::submitForm() as follows:
* @code
* $form_state['values'] = $my_form_values;
* $form_state['build_info']['args'] = array(&$object);
* drupal_form_submit('mymodule_form', $form_state);
* @endcode
* For example:
* @code
* // register a new user
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* $form_state = new FormState();
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* $form_state['values']['name'] = 'robo-user';
* $form_state['values']['mail'] = 'robouser@example.com';
* $form_state['values']['pass']['pass1'] = 'password';
* $form_state['values']['pass']['pass2'] = 'password';
* $form_state['values']['op'] = t('Create new account');
* drupal_form_submit('user_register_form', $form_state);
* @endcode
*/
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public function submitForm($form_arg, FormStateInterface &$form_state);
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/**
* Retrieves the structured array that defines a given form.
*
* @param string $form_id
* The unique string identifying the desired form. If a function
* with that name exists, it is called to build the form array.
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* @param \Drupal\Core\Form\FormStateInterface $form_state
* The current state of the form, including the additional arguments to
* self::getForm() or self::submitForm() in the 'args' component of the
* array.
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*
* @return mixed|\Symfony\Component\HttpFoundation\Response
*/
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public function retrieveForm($form_id, FormStateInterface &$form_state);
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/**
* Processes a form submission.
*
* This function is the heart of form API. The form gets built, validated and
* in appropriate cases, submitted and rebuilt.
*
* @param string $form_id
* The unique string identifying the current form.
* @param array $form
* An associative array containing the structure of the form.
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* @param \Drupal\Core\Form\FormStateInterface $form_state
* The current state of the form. This includes the current persistent
* storage data for the form, and any data passed along by earlier steps
* when displaying a multi-step form. Additional information, like the
* sanitized \Drupal::request()->request data, is also accumulated here.
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*
* @return \Symfony\Component\HttpFoundation\RedirectResponse|null
*/
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public function processForm($form_id, &$form, FormStateInterface &$form_state);
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/**
* Prepares a structured form array.
*
* Adds required elements, executes any hook_form_alter functions, and
* optionally inserts a validation token to prevent tampering.
*
* @param string $form_id
* A unique string identifying the form for validation, submission,
* theming, and hook_form_alter functions.
* @param array $form
* An associative array containing the structure of the form.
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* @param \Drupal\Core\Form\FormStateInterface $form_state
* The current state of the form. Passed in here so that hook_form_alter()
* calls can use it, as well.
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*/
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public function prepareForm($form_id, &$form, FormStateInterface &$form_state);
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/**
* Builds and processes all elements in the structured form array.
*
* Adds any required properties to each element, maps the incoming input data
* to the proper elements, and executes any #process handlers attached to a
* specific element.
*
* This is one of the three primary functions that recursively iterates a form
* array. This one does it for completing the form building process. The other
* two are self::doValidateForm() (invoked via self::validateForm() and used
* to invoke validation logic for each element) and drupal_render() (for
* rendering each element). Each of these three pipelines provides ample
* opportunity for modules to customize what happens. For example, during this
* function's life cycle, the following functions get called for each element:
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* - $element['#value_callback']: A callable that implements how user input is
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* mapped to an element's #value property. This defaults to a function named
* 'form_type_TYPE_value' where TYPE is $element['#type'].
* - $element['#process']: An array of functions called after user input has
* been mapped to the element's #value property. These functions can be used
* to dynamically add child elements: for example, for the 'date' element
* type, one of the functions in this array is form_process_datetime(),
* which adds the individual 'date', and 'time'. child elements. These
* functions can also be used to set additional properties or implement
* special logic other than adding child elements: for example, for the
* 'details' element type, one of the functions in this array is
* form_process_details(), which adds the attributes and JavaScript needed
* to make the details work in older browsers. The #process functions are
* called in preorder traversal, meaning they are called for the parent
* element first, then for the child elements.
* - $element['#after_build']: An array of callables called after
* self::doBuildForm() is done with its processing of the element. These are
* called in postorder traversal, meaning they are called for the child
* elements first, then for the parent element.
* There are similar properties containing callback functions invoked by
* self::doValidateForm() and drupal_render(), appropriate for those
* operations.
*
* Developers are strongly encouraged to integrate the functionality needed by
* their form or module within one of these three pipelines, using the
* appropriate callback property, rather than implementing their own recursive
* traversal of a form array. This facilitates proper integration between
* multiple modules. For example, module developers are familiar with the
* relative order in which hook_form_alter() implementations and #process
* functions run. A custom traversal function that affects the building of a
* form is likely to not integrate with hook_form_alter() and #process in the
* expected way. Also, deep recursion within PHP is both slow and memory
* intensive, so it is best to minimize how often it's done.
*
* As stated above, each element's #process functions are executed after its
* #value has been set. This enables those functions to execute conditional
* logic based on the current value. However, all of self::doBuildForm() runs
* before self::validateForm() is called, so during #process function
* execution, the element's #value has not yet been validated, so any code
* that requires validated values must reside within a submit handler.
*
* As a security measure, user input is used for an element's #value only if
* the element exists within $form, is not disabled (as per the #disabled
* property), and can be accessed (as per the #access property, except that
* forms submitted using self::submitForm() bypass #access restrictions). When
* user input is ignored due to #disabled and #access restrictions, the
* element's default value is used.
*
* Because of the preorder traversal, where #process functions of an element
* run before user input for its child elements is processed, and because of
* the Form API security of user input processing with respect to #access and
* #disabled described above, this generally means that #process functions
* should not use an element's (unvalidated) #value to affect the #disabled or
* #access of child elements. Use-cases where a developer may be tempted to
* implement such conditional logic usually fall into one of two categories:
* - Where user input from the current submission must affect the structure of
* a form, including properties like #access and #disabled that affect how
* the next submission needs to be processed, a multi-step workflow is
* needed. This is most commonly implemented with a submit handler setting
* persistent data within $form_state based on *validated* values in
* $form_state['values'] and setting $form_state['rebuild']. The form
* building functions must then be implemented to use the $form_state data
* to rebuild the form with the structure appropriate for the new state.
* - Where user input must affect the rendering of the form without affecting
* its structure, the necessary conditional rendering logic should reside
* within functions that run during the rendering phase (#pre_render,
* #theme, #theme_wrappers, and #post_render).
*
* @param string $form_id
* A unique string identifying the form for validation, submission,
* theming, and hook_form_alter functions.
* @param array $element
* An associative array containing the structure of the current element.
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* @param \Drupal\Core\Form\FormStateInterface $form_state
* The current state of the form. In this context, it is used to accumulate
* information about which button was clicked when the form was submitted,
* as well as the sanitized \Drupal::request()->request data.
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*
* @return array
*/
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public function doBuildForm($form_id, &$element, FormStateInterface &$form_state);