195 lines
7.4 KiB
PHP
195 lines
7.4 KiB
PHP
<?php
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/**
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* @file
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* Functions implementing Field API multilingual support.
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*/
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use Drupal\Core\Language\Language;
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use Drupal\Core\Entity\EntityInterface;
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use Drupal\field\FieldInterface;
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/**
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* @defgroup field_language Field Language API
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* @{
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* Handles multilingual fields.
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*
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* Fields natively implement multilingual support, and all fields use the
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* following structure:
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* @code
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* $entity->{$field_name}[$langcode][$delta][$column_name]
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* @endcode
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* Every field can hold a single or multiple value for each language code
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* belonging to the available language codes set:
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* - For untranslatable fields this set is only Language::LANGCODE_DEFAULT.
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* - For translatable fields this set can contain any language code. By default
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* it is the list returned by field_content_languages(), which contains all
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* installed languages with the addition of Language::LANGCODE_NOT_SPECIFIED.
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* This default can be altered by modules implementing
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* hook_field_available_languages_alter().
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*
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* The available language codes for a particular field are returned by
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* field_available_languages(). Whether a field is translatable is determined by
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* calling field_is_translatable(), which checks the $field['translatable']
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* property returned by field_info_field() and whether the entity type the field
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* is attached to supports translation.
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*
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* By default, field_invoke_method() processes a field in all available
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* languages, unless it is given a language code suggestion. Based on that
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* suggestion, _field_language_suggestion() determines the languages to act on.
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*
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* Most field_attach_*() functions act on all available language codes, except
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* for the following:
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* - field_attach_form() only takes a single language code, specifying which
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* language the field values will be submitted in.
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* - field_attach_view() requires the language the entity will be displayed in.
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* Since it is unknown whether a field translation exists for the requested
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* language, the translation handler is responsible for performing one of the
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* following actions:
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* - Ignore missing translations, i.e. do not show any field values for the
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* requested language. For example, see field_field_language_alter().
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* - Provide a value in a different language as fallback. By default, the
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* fallback logic is applied separately to each field to ensure that there
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* is a value for each field to display.
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* The field language fallback logic relies on the global language fallback
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* configuration. Therefore, the displayed field values can be in the
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* requested language, but may be different if no values for the requested
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* language are available. The default language fallback rules inspect all the
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* enabled languages ordered by their weight. This behavior can be altered or
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* even disabled by modules implementing hook_field_language_alter(), making
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* it possible to choose the first approach. The display language for each
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* field is returned by field_language().
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*
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* See @link field Field API @endlink for information about the other parts of
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* the Field API.
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*/
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/**
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* Collects the available language codes for the given entity type and field.
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*
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* If the given field has language support enabled, an array of available
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* language codes will be returned, otherwise only Language::LANGCODE_DEFAULT
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* will be returned. Since the default value for a 'translatable' entity
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* property is FALSE, we ensure that only entities that are able to handle
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* translations actually get translatable fields.
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*
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* @param $entity_type
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* The type of the entity the field is attached to, e.g. 'node' or 'user'.
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* @param $field
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* A field structure.
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*
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* @return
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* An array of valid language codes.
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*/
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function field_available_languages($entity_type, FieldInterface $field) {
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static $drupal_static_fast;
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if (!isset($drupal_static_fast)) {
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$drupal_static_fast['field_langcodes'] = &drupal_static(__FUNCTION__);
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}
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$field_langcodes = &$drupal_static_fast['field_langcodes'];
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$field_name = $field->getFieldName();
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if (!isset($field_langcodes[$entity_type][$field_name])) {
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// If the field has language support enabled we retrieve an (alterable) list
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// of enabled languages, otherwise we return Language::LANGCODE_DEFAULT.
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if (field_is_translatable($entity_type, $field)) {
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$langcodes = field_content_languages();
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// Let other modules alter the available languages.
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$context = array('entity_type' => $entity_type, 'field' => $field);
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drupal_alter('field_available_languages', $langcodes, $context);
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$field_langcodes[$entity_type][$field_name] = $langcodes;
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}
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else {
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$field_langcodes[$entity_type][$field_name] = array(Language::LANGCODE_DEFAULT);
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}
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}
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return $field_langcodes[$entity_type][$field_name];
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}
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/**
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* Process the language code suggestion based on the available language codes.
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*
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* If a non-empty language code suggestion is provided it must appear among the
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* available language codes, otherwise it will be ignored.
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*
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* @param $available_langcodes
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* An array of valid language codes.
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* @param $langcode_suggestion
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* A language code or an array of language codes keyed by field name.
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* @param $field_name
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* The name of the field being processed.
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*
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* @return
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* An array of valid language codes.
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*/
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function _field_language_suggestion($available_langcodes, $langcode_suggestion, $field_name) {
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// Handle possible language suggestions.
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if (!empty($langcode_suggestion)) {
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// We might have an array of language suggestions keyed by field name.
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if (is_array($langcode_suggestion) && isset($langcode_suggestion[$field_name])) {
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$langcode_suggestion = $langcode_suggestion[$field_name];
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}
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// If we have a single language code suggestion and it is available, we just
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// return it.
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if (in_array($langcode_suggestion, $available_langcodes)) {
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$available_langcodes = array($langcode_suggestion);
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}
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}
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return $available_langcodes;
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}
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/**
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* Returns available content language codes.
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*
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* @return
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* An array of language codes.
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*/
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function field_content_languages() {
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return array_keys(language_list(Language::STATE_ALL));
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}
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/**
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* Checks whether a field has language support.
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*
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* A field has language support enabled if its 'translatable' property is set to
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* TRUE, and its entity type has at least one translation handler registered.
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*
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* @param $entity_type
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* The type of the entity the field is attached to.
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* @param $field
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* A field data structure.
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*
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* @return
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* TRUE if the field can be translated.
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*/
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function field_is_translatable($entity_type, FieldInterface $field) {
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return $field->isFieldTranslatable() && field_has_translation_handler($entity_type);
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}
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/**
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* Checks if a module is registered as a translation handler for a given entity.
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*
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* If no handler is passed, the function simply checks if there is any
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* translation handler enabled for the given entity type.
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*
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* @param $entity_type
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* The type of the entity whose fields are to be translated.
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* @param $handler
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* (optional) The name of the handler to be checked. Defaults to NULL.
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*
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* @return
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* TRUE, if the given handler is allowed to manage field translations. If no
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* handler is passed, TRUE means there is at least one registered translation
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* handler.
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*
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* @todo Remove this once the migration to the Entity Field API is complete.
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*/
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function field_has_translation_handler($entity_type, $handler = NULL) {
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$info = entity_get_info($entity_type);
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return !empty($info['translatable']);
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}
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