1 files changed, 468 insertions, 0 deletions
diff --git a/core/includes/language.inc b/core/includes/language.inc
new file mode 100644
index 00000000000..685a4d44a00
--- /dev/null
+++ b/core/includes/language.inc
@@ -0,0 +1,468 @@
+<?php
+
+/**
+ * @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);
+}
+
+/**
+ * Updates the language type configuration.
+ */
+function language_types_set() {
+  // Ensure that we are getting the defined language negotiation information. An
+  // invocation of module_enable() or module_disable() could outdate the cached
+  // information.
+  drupal_static_reset('language_types_info');
+  drupal_static_reset('language_negotiation_info');
+
+  // Determine which language types are configurable and which not by checking
+  // whether the 'fixed' key is defined. Non-configurable (fixed) language types
+  // have their language negotiation settings stored there.
+  $defined_providers = language_negotiation_info();
+  foreach (language_types_info() as $type => $info) {
+    if (isset($info['fixed'])) {
+      $language_types[$type] = FALSE;
+      $negotiation = array();
+      foreach ($info['fixed'] as $weight => $id) {
+        if (isset($defined_providers[$id])) {
+          $negotiation[$id] = $weight;
+        }
+      }
+      language_negotiation_set($type, $negotiation);
+    }
+    else {
+      $language_types[$type] = TRUE;
+    }
+  }
+
+  // Save language types.
+  variable_set('language_types', $language_types);
+
+  // Ensure that subsequent calls of language_types_configurable() return the
+  // updated language type information.
+  drupal_static_reset('language_types_configurable');
+}
+
+/**
+ * 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;
+}
+
+/**
+ * Updates language configuration to remove any language provider that is no longer defined.
+ */
+function language_negotiation_purge() {
+  // Ensure that we are getting the defined language negotiation information. An
+  // invocation of module_enable() or module_disable() could outdate the cached
+  // information.
+  drupal_static_reset('language_negotiation_info');
+  drupal_static_reset('language_types_info');
+
+  $defined_providers = language_negotiation_info();
+  foreach (language_types_info() as $type => $type_info) {
+    $weight = 0;
+    $negotiation = array();
+    foreach (variable_get("language_negotiation_$type", array()) as $id => $provider) {
+      if (isset($defined_providers[$id])) {
+        $negotiation[$id] = $weight++;
+      }
+    }
+    language_negotiation_set($type, $negotiation);
+  }
+}
+
+/**
+ * Save a list of language providers.
+ *
+ * @param $type
+ *   The language negotiation type.
+ * @param $language_providers
+ *   An array of language provider weights keyed by id.
+ *   @see language_provider_weight()
+ */
+function language_negotiation_set($type, $language_providers) {
+  // Save only the necessary fields.
+  $provider_fields = array('callbacks', 'file', 'cache');
+
+  $negotiation = array();
+  $providers_weight = array();
+  $defined_providers = language_negotiation_info();
+  $default_types = language_types_configurable(FALSE);
+
+  // Initialize the providers weight list.
+  foreach ($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 language'),
+      'description' => t('Use the default site language (@language_name).', array('@language_name' => language_default()->name)),
+      'config' => 'admin/config/regional/language',
+    );
+
+    // 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;
+}