cms/drupal/modules/field/field.multilingual.inc
changeset 541 e756a8c72c3d
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/cms/drupal/modules/field/field.multilingual.inc	Fri Sep 08 12:04:06 2017 +0200
@@ -0,0 +1,301 @@
+<?php
+
+/**
+ * @file
+ * Functions implementing Field API multilingual support.
+ */
+
+/**
+ * @defgroup field_language Field Language API
+ * @{
+ * Handling of multilingual fields.
+ *
+ * Fields natively implement multilingual support, and all fields use the
+ * following structure:
+ * @code
+ * $entity->{$field_name}[$langcode][$delta][$column_name]
+ * @endcode
+ * Every field can hold a single or multiple value for each language belonging
+ * to the available languages set:
+ * - For untranslatable fields this set only contains LANGUAGE_NONE.
+ * - For translatable fields this set can contain any language code. By default
+ *   it is the list returned by field_content_languages(), which contains all
+ *   installed languages with the addition of LANGUAGE_NONE. This default can be
+ *   altered by modules implementing hook_field_available_languages_alter().
+ *
+ * The available languages for a particular field are returned by
+ * field_available_languages(). Whether a field is translatable is determined by
+ * calling field_is_translatable(), which checks the $field['translatable']
+ * property returned by field_info_field(), and whether there is at least one
+ * translation handler available for the field. A translation handler is a
+ * module registering itself via hook_entity_info() to handle field
+ * translations.
+ *
+ * By default, _field_invoke() and _field_invoke_multiple() are processing a
+ * field in all available languages, unless they are given a language
+ * suggestion. Based on that suggestion, _field_language_suggestion() determines
+ * the languages to act on.
+ *
+ * Most field_attach_*() functions act on all available languages, except for
+ * the following:
+ * - field_attach_form() only takes a single language code, specifying which
+ *   language the field values will be submitted in.
+ * - field_attach_view() requires the language the entity will be displayed in.
+ *   Since it is unknown whether a field translation exists for the requested
+ *   language, the translation handler is responsible for performing one of the
+ *   following actions:
+ *   - Ignore missing translations, i.e. do not show any field values for the
+ *     requested language. For example, see locale_field_language_alter().
+ *   - Provide a value in a different language as fallback. By default, the
+ *     fallback logic is applied separately to each field to ensure that there
+ *     is a value for each field to display.
+ *   The field language fallback logic relies on the global language fallback
+ *   configuration. Therefore, the displayed field values can be in the
+ *   requested language, but may be different if no values for the requested
+ *   language are available. The default language fallback rules inspect all the
+ *   enabled languages ordered by their weight. This behavior can be altered or
+ *   even disabled by modules implementing hook_field_language_alter(), making
+ *   it possible to choose the first approach. The display language for each
+ *   field is returned by field_language().
+ *
+ * See @link field Field API @endlink for information about the other parts of
+ * the Field API.
+ */
+
+/**
+ * Implements hook_multilingual_settings_changed().
+ */
+function field_multilingual_settings_changed() {
+  field_info_cache_clear();
+}
+
+/**
+ * Collects the available languages for the given entity type and field.
+ *
+ * If the given field has language support enabled, an array of available
+ * languages will be returned, otherwise only LANGUAGE_NONE will be returned.
+ * Since the default value for a 'translatable' entity property is FALSE, we
+ * ensure that only entities that are able to handle translations actually get
+ * translatable fields.
+ *
+ * @param $entity_type
+ *   The type of the entity the field is attached to, e.g. 'node' or 'user'.
+ * @param $field
+ *   A field structure.
+ *
+ * @return
+ *   An array of valid language codes.
+ */
+function field_available_languages($entity_type, $field) {
+  static $drupal_static_fast;
+  if (!isset($drupal_static_fast)) {
+    $drupal_static_fast['field_languages'] = &drupal_static(__FUNCTION__);
+  }
+  $field_languages = &$drupal_static_fast['field_languages'];
+  $field_name = $field['field_name'];
+
+  if (!isset($field_languages[$entity_type][$field_name])) {
+    // If the field has language support enabled we retrieve an (alterable) list
+    // of enabled languages, otherwise we return just LANGUAGE_NONE.
+    if (field_is_translatable($entity_type, $field)) {
+      $languages = field_content_languages();
+      // Let other modules alter the available languages.
+      $context = array('entity_type' => $entity_type, 'field' => $field);
+      drupal_alter('field_available_languages', $languages, $context);
+      $field_languages[$entity_type][$field_name] = $languages;
+    }
+    else {
+      $field_languages[$entity_type][$field_name] = array(LANGUAGE_NONE);
+    }
+  }
+
+  return $field_languages[$entity_type][$field_name];
+}
+
+/**
+ * Process the given language suggestion based on the available languages.
+ *
+ * If a non-empty language suggestion is provided it must appear among the
+ * available languages, otherwise it will be ignored.
+ *
+ * @param $available_languages
+ *   An array of valid language codes.
+ * @param $language_suggestion
+ *   A language code or an array of language codes keyed by field name.
+ * @param $field_name
+ *   The name of the field being processed.
+ *
+ * @return
+ *   An array of valid language codes.
+ */
+function _field_language_suggestion($available_languages, $language_suggestion, $field_name) {
+  // Handle possible language suggestions.
+  if (!empty($language_suggestion)) {
+    // We might have an array of language suggestions keyed by field name.
+    if (is_array($language_suggestion) && isset($language_suggestion[$field_name])) {
+      $language_suggestion = $language_suggestion[$field_name];
+    }
+
+    // If we have a language suggestion and the suggested language is available,
+    // we return only it.
+    if (in_array($language_suggestion, $available_languages)) {
+      $available_languages = array($language_suggestion);
+    }
+  }
+
+  return $available_languages;
+}
+
+/**
+ * Returns available content languages.
+ *
+ * The languages that may be associated to fields include LANGUAGE_NONE.
+ *
+ * @return
+ *   An array of language codes.
+ */
+function field_content_languages() {
+  return array_keys(language_list() + array(LANGUAGE_NONE => NULL));
+}
+
+/**
+ * Checks whether a field has language support.
+ *
+ * A field has language support enabled if its 'translatable' property is set to
+ * TRUE, and its entity type has at least one translation handler registered.
+ *
+ * @param $entity_type
+ *   The type of the entity the field is attached to.
+ * @param $field
+ *   A field data structure.
+ *
+ * @return
+ *   TRUE if the field can be translated.
+ */
+function field_is_translatable($entity_type, $field) {
+  return $field['translatable'] && field_has_translation_handler($entity_type);
+}
+
+/**
+ * Checks if a module is registered as a translation handler for a given entity.
+ *
+ * If no handler is passed, simply check if there is any translation handler
+ * enabled for the given entity type.
+ *
+ * @param $entity_type
+ *   The type of the entity whose fields are to be translated.
+ * @param $handler
+ *   (optional) The name of the handler to be checked. Defaults to NULL.
+ *
+ * @return
+ *   TRUE, if the given handler is allowed to manage field translations. If no
+ *   handler is passed, TRUE means there is at least one registered translation
+ *   handler.
+ */
+function field_has_translation_handler($entity_type, $handler = NULL) {
+  $entity_info = entity_get_info($entity_type);
+
+  if (isset($handler)) {
+    return !empty($entity_info['translation'][$handler]);
+  }
+  elseif (isset($entity_info['translation'])) {
+    foreach ($entity_info['translation'] as $handler_info) {
+      // The translation handler must use a non-empty data structure.
+      if (!empty($handler_info)) {
+        return TRUE;
+      }
+    }
+  }
+
+  return FALSE;
+}
+
+/**
+ * Ensures that a given language code is valid.
+ *
+ * Checks whether the given language is one of the enabled languages. Otherwise,
+ * it returns the current, global language; or the site's default language, if
+ * the additional parameter $default is TRUE.
+ *
+ * @param $langcode
+ *   The language code to validate.
+ * @param $default
+ *   Whether to return the default language code or the current language code in
+ *   case $langcode is invalid.
+ * @return
+ *   A valid language code.
+ */
+function field_valid_language($langcode, $default = TRUE) {
+  $enabled_languages = field_content_languages();
+  if (in_array($langcode, $enabled_languages)) {
+    return $langcode;
+  }
+  global $language_content;
+  return $default ? language_default('language') : $language_content->language;
+}
+
+/**
+ * Returns the display language for the fields attached to the given entity.
+ *
+ * The actual language for each given field is determined based on the requested
+ * language and the actual data available in the fields themselves.
+ * If there is no registered translation handler for the given entity type, the
+ * display language to be used is just LANGUAGE_NONE, as no other language code
+ * is allowed by field_available_languages().
+ * If translation handlers are found, we let modules provide alternative display
+ * languages for fields not having the requested language available.
+ * Core language fallback rules are provided by locale_field_language_fallback()
+ * which is called by locale_field_language_alter().
+ *
+ * @param $entity_type
+ *   The type of $entity.
+ * @param $entity
+ *   The entity to be displayed.
+ * @param $field_name
+ *   (optional) The name of the field to be displayed. Defaults to NULL. If
+ *   no value is specified, the display languages for every field attached to
+ *   the given entity will be returned.
+ * @param $langcode
+ *   (optional) The language code $entity has to be displayed in. Defaults to
+ *   NULL. If no value is given the current language will be used.
+ *
+ * @return
+ *   A language code if a field name is specified, an array of language codes
+ *   keyed by field name otherwise.
+ */
+function field_language($entity_type, $entity, $field_name = NULL, $langcode = NULL) {
+  $display_languages = &drupal_static(__FUNCTION__, array());
+  list($id, , $bundle) = entity_extract_ids($entity_type, $entity);
+  $langcode = field_valid_language($langcode, FALSE);
+
+  if (!isset($display_languages[$entity_type][$id][$langcode])) {
+    $display_language = array();
+
+    // By default display language is set to LANGUAGE_NONE if the field
+    // translation is not available. It is up to translation handlers to
+    // implement language fallback rules.
+    foreach (field_info_instances($entity_type, $bundle) as $instance) {
+      $display_language[$instance['field_name']] = isset($entity->{$instance['field_name']}[$langcode]) ? $langcode : LANGUAGE_NONE;
+    }
+
+    if (field_has_translation_handler($entity_type)) {
+      $context = array(
+        'entity_type' => $entity_type,
+        'entity' => $entity,
+        'language' => $langcode,
+      );
+      drupal_alter('field_language', $display_language, $context);
+    }
+
+    $display_languages[$entity_type][$id][$langcode] = $display_language;
+  }
+
+  $display_language = $display_languages[$entity_type][$id][$langcode];
+
+  // Single-field mode.
+  if (isset($field_name)) {
+    return isset($display_language[$field_name]) ? $display_language[$field_name] : FALSE;
+  }
+
+  return $display_language;
+}