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Drupal example source code file (language.inc)

This example Drupal source code file (language.inc) is included in the DevDaily.com "Drupal Source Code Warehouse" project. The intent of this project is to help you "Learn Drupal by Example".

PHP - Drupal tags/keywords

array, as, foreach, function, if, isset, languages, negotiation, php, provider, provider_id, return, type, variable

The language.inc Drupal example source code

<?php
// $Id: language.inc,v 1.30 2010/05/12 08:26:14 dries Exp $

/**
 * @file
 * Multiple language handling functionality.
 */

/**
 * No language negotiation. The default language is used.
 */
define('LANGUAGE_NEGOTIATION_DEFAULT', 'language-default');

/**
 * Return all the defined language types.
 *
 * @return
 *   An array of language type names. The name will be used as the global
 *   variable name the language value will be stored in.
 */
function language_types_info() {
  $language_types = &drupal_static(__FUNCTION__);

  if (!isset($language_types)) {
    $language_types = module_invoke_all('language_types_info');
    // Let other modules alter the list of language types.
    drupal_alter('language_types_info', $language_types);
  }

  return $language_types;
}

/**
 * Return only the configurable language types.
 *
 * A language type maybe configurable or fixed. A fixed language type is a type
 * whose negotiation values are unchangeable and defined while defining the
 * language type itself.
 *
 * @param $stored
 *   Optional. By default retrieves values from the 'language_types' variable to
 *   avoid unnecessary hook invocations.
 *   If set to FALSE retrieves values from the actual language type definitions.
 *   This allows to react to alterations performed on the definitions by modules
 *   installed after the 'language_types' variable is set.
 *
 * @return
 *   An array of language type names.
 */
function language_types_configurable($stored = TRUE) {
  $configurable = &drupal_static(__FUNCTION__);

  if ($stored && !isset($configurable)) {
    $types = variable_get('language_types', drupal_language_types());
    $configurable = array_keys(array_filter($types));
  }

  if (!$stored) {
    $result = array();
    foreach (language_types_info() as $type => $info) {
      if (!isset($info['fixed'])) {
        $result[] = $type;
      }
    }
    return $result;
  }

  return $configurable;
}

/**
 * Disable the given language types.
 *
 * @param $types
 *   An array of language types.
 */
function language_types_disable($types) {
  $enabled_types = variable_get('language_types', drupal_language_types());

  foreach ($types as $type) {
    unset($enabled_types[$type]);
  }

  variable_set('language_types', $enabled_types);
}

/**
 * Check if a language provider is enabled.
 *
 * This has two possible behaviors:
 *  - If $provider_id is given return its ID if enabled, FALSE otherwise.
 *  - If no ID is passed the first enabled language provider is returned.
 *
 * @param $type
 *   The language negotiation type.
 * @param $provider_id
 *   The language provider ID.
 *
 * @return
 *   The provider ID if it is enabled, FALSE otherwise.
 */
function language_negotiation_get($type, $provider_id = NULL) {
  $negotiation = variable_get("language_negotiation_$type", array());

  if (empty($negotiation)) {
    return empty($provider_id) ? LANGUAGE_NEGOTIATION_DEFAULT : FALSE;
  }

  if (empty($provider_id)) {
    return key($negotiation);
  }

  if (isset($negotiation[$provider_id])) {
    return $provider_id;
  }

  return FALSE;
}

/**
 * Check if the given language provider is enabled for any configurable language
 * type.
 *
 * @param $provider_id
 *   The language provider ID.
 *
 * @return
 *   TRUE if there is at least one language type for which the give language
 *   provider is enabled, FALSE otherwise.
 */
function language_negotiation_get_any($provider_id) {
  foreach (language_types_configurable() as $type) {
    if (language_negotiation_get($type, $provider_id)) {
      return TRUE;
    }
  }

  return FALSE;
}

/**
 * Return the language switch links for the given language.
 *
 * @param $type
 *   The language negotiation type.
 * @param $path
 *   The internal path the switch links will be relative to.
 *
 * @return
 *   A keyed array of links ready to be themed.
 */
function language_negotiation_get_switch_links($type, $path) {
  $links = FALSE;
  $negotiation = variable_get("language_negotiation_$type", array());

  foreach ($negotiation as $id => $provider) {
    if (isset($provider['callbacks']['switcher'])) {
      if (isset($provider['file'])) {
        require_once DRUPAL_ROOT . '/' . $provider['file'];
      }

      $callback = $provider['callbacks']['switcher'];
      $result = $callback($type, $path);

      if (!empty($result)) {
        // Allow modules to provide translations for specific links.
        drupal_alter('language_switch_links', $result, $type, $path);
        $links = (object) array('links' => $result, 'provider' => $id);
        break;
      }
    }
  }

  return $links;
}


/**
 * Save a list of language providers.
 *
 * @param $type
 *   The language negotiation type.
 * @param $language_providers
 *   An array of language provider ids.
 */
function language_negotiation_set($type, $language_providers) {
  // Save only the necessary fields.
  $provider_fields = array('callbacks', 'file', 'cache');

  $negotiation = array();
  $providers_weight = array();
  $defined_providers = language_negotiation_info();
  $default_types = language_types_configurable();

  // Initialize the providers weight list.
  foreach ($language_providers as $id => $provider) {
    $providers_weight[$id] = language_provider_weight($provider);
  }

  // Order providers list by weight.
  asort($providers_weight);

  foreach ($providers_weight as $id => $weight) {
    if (isset($defined_providers[$id])) {
      $provider = $defined_providers[$id];
      // If the provider does not express any preference about types, make it
      // available for any configurable type.
      $types = array_flip(isset($provider['types']) ? $provider['types'] : $default_types);
      // Check if the provider is defined and has the right type.
      if (isset($types[$type])) {
        $provider_data = array();
        foreach ($provider_fields as $field) {
          if (isset($provider[$field])) {
            $provider_data[$field] = $provider[$field];
          }
        }
        $negotiation[$id] = $provider_data;
      }
    }
  }

  variable_set("language_negotiation_$type", $negotiation);
}

/**
 * Return all the defined language providers.
 *
 * @return
 *   An array of language providers.
 */
function language_negotiation_info() {
  $language_providers = &drupal_static(__FUNCTION__);

  if (!isset($language_providers)) {
    // Collect all the module-defined language negotiation providers.
    $language_providers = module_invoke_all('language_negotiation_info');

    // Add the default language provider.
    $language_providers[LANGUAGE_NEGOTIATION_DEFAULT] = array(
      'callbacks' => array('language' => 'language_from_default'),
      'weight' => 10,
      'name' => t('Default'),
      'description' => t('Use the default site language (@language_name).', array('@language_name' => language_default()->native)),
    );

    // Let other modules alter the list of language providers.
    drupal_alter('language_negotiation_info', $language_providers);
  }

  return $language_providers;
}

/**
 * Helper function used to cache the language providers results.
 *
 * @param $provider_id
 *   The language provider ID.
 * @param $provider
 *   The language provider to be invoked. If not passed it will be explicitly
 *   loaded through language_negotiation_info().
 *
 * @return
 *   The language provider's return value.
 */
function language_provider_invoke($provider_id, $provider = NULL) {
  $results = &drupal_static(__FUNCTION__);

  if (!isset($results[$provider_id])) {
    global $user;

    // Get languages grouped by status and select only the enabled ones.
    $languages = language_list('enabled');
    $languages = $languages[1];

    if (!isset($provider)) {
      $providers = language_negotiation_info();
      $provider = $providers[$provider_id];
    }

    if (isset($provider['file'])) {
      require_once DRUPAL_ROOT . '/' . $provider['file'];
    }

    // If the language provider has no cache preference or this is satisfied
    // we can execute the callback.
    $cache = !isset($provider['cache']) || $user->uid || $provider['cache'] == variable_get('cache', 0);
    $callback = isset($provider['callbacks']['language']) ? $provider['callbacks']['language'] : FALSE;
    $langcode = $cache && function_exists($callback) ? $callback($languages) : FALSE;
    $results[$provider_id] = isset($languages[$langcode]) ? $languages[$langcode] : FALSE;
  }

  return $results[$provider_id];
}

/**
 * Return the passed language provider weight or a default value.
 *
 * @param $provider
 *   A language provider data structure.
 *
 * @return
 *   A numeric weight.
 */
function language_provider_weight($provider) {
  $default = is_numeric($provider) ? $provider : 0;
  return isset($provider['weight']) && is_numeric($provider['weight']) ? $provider['weight'] : $default;
}

/**
 * Choose a language for the given type based on language negotiation settings.
 *
 * @param $type
 *   The language type.
 *
 * @return
 *   The negotiated language object.
 */
function language_initialize($type) {
  // Execute the language providers in the order they were set up and return the
  // first valid language found.
  $negotiation = variable_get("language_negotiation_$type", array());

  foreach ($negotiation as $id => $provider) {
    $language = language_provider_invoke($id, $provider);
    if ($language) {
      return $language;
    }
  }

  // If no other language was found use the default one.
  return language_default();
}

/**
 * Default language provider.
 *
 * @return
 *   The default language code.
 */
function language_from_default() {
  return language_default()->language;
}

/**
 * Split the given path into prefix and actual path.
 *
 * Parse the given path and return the language object identified by the
 * prefix and the actual path.
 *
 * @param $path
 *   The path to split.
 * @param $languages
 *   An array of valid languages.
 *
 * @return
 *   An array composed of:
 *    - A language object corresponding to the identified prefix on success,
 *      FALSE otherwise.
 *    - The path without the prefix on success, the given path otherwise.
 */
function language_url_split_prefix($path, $languages) {
  $args = empty($path) ? array() : explode('/', $path);
  $prefix = array_shift($args);

  // Search prefix within enabled languages.
  foreach ($languages as $language) {
    if (!empty($language->prefix) && $language->prefix == $prefix) {
      // Rebuild $path with the language removed.
      return array($language, implode('/', $args));
    }
  }

  return array(FALSE, $path);
}

/**
 * Return the possible fallback languages ordered by language weight.
 *
 * @param
 *   The language type.
 *
 * @return
 *   An array of language codes.
 */
function language_fallback_get_candidates($type = LANGUAGE_TYPE_CONTENT) {
  $fallback_candidates = &drupal_static(__FUNCTION__);

  if (!isset($fallback_candidates)) {
    $fallback_candidates = array();

    // Get languages ordered by weight.
    // Use array keys to avoid duplicated entries.
    foreach (language_list('weight') as $languages) {
      foreach ($languages as $language) {
        $fallback_candidates[$language->language] = NULL;
      }
    }

    $fallback_candidates = array_keys($fallback_candidates);
    $fallback_candidates[] = LANGUAGE_NONE;

    // Let other modules hook in and add/change candidates.
    drupal_alter('language_fallback_candidates', $fallback_candidates);
  }

  return $fallback_candidates;
}

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