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+<?php
+
+/**
+ * @file
+ * API for loading and interacting with Drupal modules.
+ */
+
+/**
+ * Loads all the modules that have been enabled in the system table.
+ *
+ * @param $bootstrap
+ * Whether to load only the reduced set of modules loaded in "bootstrap mode"
+ * for cached pages. See bootstrap.inc.
+ *
+ * @return
+ * If $bootstrap is NULL, return a boolean indicating whether all modules
+ * have been loaded.
+ */
+function module_load_all($bootstrap = FALSE) {
+ static $has_run = FALSE;
+
+ if (isset($bootstrap)) {
+ foreach (module_list(TRUE, $bootstrap) as $module) {
+ drupal_load('module', $module);
+ }
+ // $has_run will be TRUE if $bootstrap is FALSE.
+ $has_run = !$bootstrap;
+ }
+ return $has_run;
+}
+
+
+/**
+ * Returns a list of currently active modules.
+ *
+ * Usually, this returns a list of all enabled modules. When called early on in
+ * the bootstrap, it will return a list of vital modules only (those needed to
+ * generate cached pages).
+ *
+ * All parameters to this function are optional and should generally not be
+ * changed from their defaults.
+ *
+ * @param $refresh
+ * (optional) Whether to force the module list to be regenerated (such as
+ * after the administrator has changed the system settings). Defaults to
+ * FALSE.
+ * @param $bootstrap_refresh
+ * (optional) When $refresh is TRUE, setting $bootstrap_refresh to TRUE forces
+ * the module list to be regenerated using the reduced set of modules loaded
+ * in "bootstrap mode" for cached pages. Otherwise, setting $refresh to TRUE
+ * generates the complete list of enabled modules.
+ * @param $sort
+ * (optional) By default, modules are ordered by weight and module name. Set
+ * this option to TRUE to return a module list ordered only by module name.
+ * @param $fixed_list
+ * (optional) If an array of module names is provided, this will override the
+ * module list with the given set of modules. This will persist until the next
+ * call with $refresh set to TRUE or with a new $fixed_list passed in. This
+ * parameter is primarily intended for internal use (e.g., in install.php and
+ * update.php).
+ *
+ * @return
+ * An associative array whose keys and values are the names of the modules in
+ * the list.
+ */
+function module_list($refresh = FALSE, $bootstrap_refresh = FALSE, $sort = FALSE, $fixed_list = NULL) {
+ static $list = array(), $sorted_list;
+
+ if (empty($list) || $refresh || $fixed_list) {
+ $list = array();
+ $sorted_list = NULL;
+ if ($fixed_list) {
+ foreach ($fixed_list as $name => $module) {
+ drupal_get_filename('module', $name, $module['filename']);
+ $list[$name] = $name;
+ }
+ }
+ else {
+ if ($refresh) {
+ // For the $refresh case, make sure that system_list() returns fresh
+ // data.
+ drupal_static_reset('system_list');
+ }
+ if ($bootstrap_refresh) {
+ $list = system_list('bootstrap');
+ }
+ else {
+ // Not using drupal_map_assoc() here as that requires common.inc.
+ $list = array_keys(system_list('module_enabled'));
+ $list = (!empty($list) ? array_combine($list, $list) : array());
+ }
+ }
+ }
+ if ($sort) {
+ if (!isset($sorted_list)) {
+ $sorted_list = $list;
+ ksort($sorted_list);
+ }
+ return $sorted_list;
+ }
+ return $list;
+}
+
+/**
+ * Builds a list of bootstrap modules and enabled modules and themes.
+ *
+ * @param $type
+ * The type of list to return:
+ * - module_enabled: All enabled modules.
+ * - bootstrap: All enabled modules required for bootstrap.
+ * - theme: All themes.
+ *
+ * @return
+ * An associative array of modules or themes, keyed by name. For $type
+ * 'bootstrap', the array values equal the keys. For $type 'module_enabled'
+ * or 'theme', the array values are objects representing the respective
+ * database row, with the 'info' property already unserialized.
+ *
+ * @see module_list()
+ * @see list_themes()
+ */
+function system_list($type) {
+ $lists = &drupal_static(__FUNCTION__);
+
+ // For bootstrap modules, attempt to fetch the list from cache if possible.
+ // if not fetch only the required information to fire bootstrap hooks
+ // in case we are going to serve the page from cache.
+ if ($type == 'bootstrap') {
+ if (isset($lists['bootstrap'])) {
+ return $lists['bootstrap'];
+ }
+ if ($cached = cache_get('bootstrap_modules', 'cache_bootstrap')) {
+ $bootstrap_list = $cached->data;
+ }
+ else {
+ $bootstrap_list = db_query("SELECT name, filename FROM {system} WHERE status = 1 AND bootstrap = 1 AND type = 'module' ORDER BY weight ASC, name ASC")->fetchAllAssoc('name');
+ cache_set('bootstrap_modules', $bootstrap_list, 'cache_bootstrap');
+ }
+ // To avoid a separate database lookup for the filepath, prime the
+ // drupal_get_filename() static cache for bootstrap modules only.
+ // The rest is stored separately to keep the bootstrap module cache small.
+ foreach ($bootstrap_list as $module) {
+ drupal_get_filename('module', $module->name, $module->filename);
+ }
+ // We only return the module names here since module_list() doesn't need
+ // the filename itself.
+ $lists['bootstrap'] = array_keys($bootstrap_list);
+ }
+ // Otherwise build the list for enabled modules and themes.
+ elseif (!isset($lists['module_enabled'])) {
+ if ($cached = cache_get('system_list', 'cache_bootstrap')) {
+ $lists = $cached->data;
+ }
+ else {
+ $lists = array(
+ 'module_enabled' => array(),
+ 'theme' => array(),
+ 'filepaths' => array(),
+ );
+ // The module name (rather than the filename) is used as the fallback
+ // weighting in order to guarantee consistent behavior across different
+ // Drupal installations, which might have modules installed in different
+ // locations in the file system. The ordering here must also be
+ // consistent with the one used in module_implements().
+ $result = db_query("SELECT * FROM {system} WHERE type = 'theme' OR (type = 'module' AND status = 1) ORDER BY weight ASC, name ASC");
+ foreach ($result as $record) {
+ $record->info = unserialize($record->info);
+ // Build a list of all enabled modules.
+ if ($record->type == 'module') {
+ $lists['module_enabled'][$record->name] = $record;
+ }
+ // Build a list of themes.
+ if ($record->type == 'theme') {
+ $lists['theme'][$record->name] = $record;
+ }
+ // Build a list of filenames so drupal_get_filename can use it.
+ if ($record->status) {
+ $lists['filepaths'][] = array('type' => $record->type, 'name' => $record->name, 'filepath' => $record->filename);
+ }
+ }
+ foreach ($lists['theme'] as $key => $theme) {
+ if (!empty($theme->info['base theme'])) {
+ // Make a list of the theme's base themes.
+ require_once DRUPAL_ROOT . '/includes/theme.inc';
+ $lists['theme'][$key]->base_themes = drupal_find_base_themes($lists['theme'], $key);
+ // Don't proceed if there was a problem with the root base theme.
+ if (!current($lists['theme'][$key]->base_themes)) {
+ continue;
+ }
+ // Determine the root base theme.
+ $base_key = key($lists['theme'][$key]->base_themes);
+ // Add to the list of sub-themes for each of the theme's base themes.
+ foreach (array_keys($lists['theme'][$key]->base_themes) as $base_theme) {
+ $lists['theme'][$base_theme]->sub_themes[$key] = $lists['theme'][$key]->info['name'];
+ }
+ // Add the base theme's theme engine info.
+ $lists['theme'][$key]->info['engine'] = isset($lists['theme'][$base_key]->info['engine']) ? $lists['theme'][$base_key]->info['engine'] : 'theme';
+ }
+ else {
+ // A plain theme is its own engine.
+ $base_key = $key;
+ if (!isset($lists['theme'][$key]->info['engine'])) {
+ $lists['theme'][$key]->info['engine'] = 'theme';
+ }
+ }
+ // Set the theme engine prefix.
+ $lists['theme'][$key]->prefix = ($lists['theme'][$key]->info['engine'] == 'theme') ? $base_key : $lists['theme'][$key]->info['engine'];
+ }
+ cache_set('system_list', $lists, 'cache_bootstrap');
+ }
+ // To avoid a separate database lookup for the filepath, prime the
+ // drupal_get_filename() static cache with all enabled modules and themes.
+ foreach ($lists['filepaths'] as $item) {
+ drupal_get_filename($item['type'], $item['name'], $item['filepath']);
+ }
+ }
+
+ return $lists[$type];
+}
+
+/**
+ * Resets all system_list() caches.
+ */
+function system_list_reset() {
+ drupal_static_reset('system_list');
+ drupal_static_reset('system_rebuild_module_data');
+ drupal_static_reset('list_themes');
+ cache_clear_all('bootstrap_modules', 'cache_bootstrap');
+ cache_clear_all('system_list', 'cache_bootstrap');
+}
+
+/**
+ * Determines which modules require and are required by each module.
+ *
+ * @param $files
+ * The array of filesystem objects used to rebuild the cache.
+ *
+ * @return
+ * The same array with the new keys for each module:
+ * - requires: An array with the keys being the modules that this module
+ * requires.
+ * - required_by: An array with the keys being the modules that will not work
+ * without this module.
+ */
+function _module_build_dependencies($files) {
+ require_once DRUPAL_ROOT . '/includes/graph.inc';
+ foreach ($files as $filename => $file) {
+ $graph[$file->name]['edges'] = array();
+ if (isset($file->info['dependencies']) && is_array($file->info['dependencies'])) {
+ foreach ($file->info['dependencies'] as $dependency) {
+ $dependency_data = drupal_parse_dependency($dependency);
+ $graph[$file->name]['edges'][$dependency_data['name']] = $dependency_data;
+ }
+ }
+ }
+ drupal_depth_first_search($graph);
+ foreach ($graph as $module => $data) {
+ $files[$module]->required_by = isset($data['reverse_paths']) ? $data['reverse_paths'] : array();
+ $files[$module]->requires = isset($data['paths']) ? $data['paths'] : array();
+ $files[$module]->sort = $data['weight'];
+ }
+ return $files;
+}
+
+/**
+ * Determines whether a given module exists.
+ *
+ * @param $module
+ * The name of the module (without the .module extension).
+ *
+ * @return
+ * TRUE if the module is both installed and enabled.
+ */
+function module_exists($module) {
+ $list = module_list();
+ return isset($list[$module]);
+}
+
+/**
+ * Loads a module's installation hooks.
+ *
+ * @param $module
+ * The name of the module (without the .module extension).
+ *
+ * @return
+ * The name of the module's install file, if successful; FALSE otherwise.
+ */
+function module_load_install($module) {
+ // Make sure the installation API is available
+ include_once DRUPAL_ROOT . '/includes/install.inc';
+
+ return module_load_include('install', $module);
+}
+
+/**
+ * Loads a module include file.
+ *
+ * Examples:
+ * @code
+ * // Load node.admin.inc from the node module.
+ * module_load_include('inc', 'node', 'node.admin');
+ * // Load content_types.inc from the node module.
+ * module_load_include('inc', 'node', 'content_types');
+ * @endcode
+ *
+ * Do not use this function to load an install file, use module_load_install()
+ * instead. Do not use this function in a global context since it requires
+ * Drupal to be fully bootstrapped, use require_once DRUPAL_ROOT . '/path/file'
+ * instead.
+ *
+ * @param $type
+ * The include file's type (file extension).
+ * @param $module
+ * The module to which the include file belongs.
+ * @param $name
+ * (optional) The base file name (without the $type extension). If omitted,
+ * $module is used; i.e., resulting in "$module.$type" by default.
+ *
+ * @return
+ * The name of the included file, if successful; FALSE otherwise.
+ */
+function module_load_include($type, $module, $name = NULL) {
+ if (!isset($name)) {
+ $name = $module;
+ }
+
+ if (function_exists('drupal_get_path')) {
+ $file = DRUPAL_ROOT . '/' . drupal_get_path('module', $module) . "/$name.$type";
+ if (is_file($file)) {
+ require_once $file;
+ return $file;
+ }
+ }
+ return FALSE;
+}
+
+/**
+ * Loads an include file for each module enabled in the {system} table.
+ */
+function module_load_all_includes($type, $name = NULL) {
+ $modules = module_list();
+ foreach ($modules as $module) {
+ module_load_include($type, $module, $name);
+ }
+}
+
+/**
+ * Enables or installs a given list of modules.
+ *
+ * Definitions:
+ * - "Enabling" is the process of activating a module for use by Drupal.
+ * - "Disabling" is the process of deactivating a module.
+ * - "Installing" is the process of enabling it for the first time or after it
+ * has been uninstalled.
+ * - "Uninstalling" is the process of removing all traces of a module.
+ *
+ * Order of events:
+ * - Gather and add module dependencies to $module_list (if applicable).
+ * - For each module that is being enabled:
+ * - Install module schema and update system registries and caches.
+ * - If the module is being enabled for the first time or had been
+ * uninstalled, invoke hook_install() and add it to the list of installed
+ * modules.
+ * - Invoke hook_enable().
+ * - Invoke hook_modules_installed().
+ * - Invoke hook_modules_enabled().
+ *
+ * @param $module_list
+ * An array of module names.
+ * @param $enable_dependencies
+ * If TRUE, dependencies will automatically be added and enabled in the
+ * correct order. This incurs a significant performance cost, so use FALSE
+ * if you know $module_list is already complete and in the correct order.
+ *
+ * @return
+ * FALSE if one or more dependencies are missing, TRUE otherwise.
+ *
+ * @see hook_install()
+ * @see hook_enable()
+ * @see hook_modules_installed()
+ * @see hook_modules_enabled()
+ */
+function module_enable($module_list, $enable_dependencies = TRUE) {
+ if ($enable_dependencies) {
+ // Get all module data so we can find dependencies and sort.
+ $module_data = system_rebuild_module_data();
+ // Create an associative array with weights as values.
+ $module_list = array_flip(array_values($module_list));
+
+ while (list($module) = each($module_list)) {
+ if (!isset($module_data[$module])) {
+ // This module is not found in the filesystem, abort.
+ return FALSE;
+ }
+ if ($module_data[$module]->status) {
+ // Skip already enabled modules.
+ unset($module_list[$module]);
+ continue;
+ }
+ $module_list[$module] = $module_data[$module]->sort;
+
+ // Add dependencies to the list, with a placeholder weight.
+ // The new modules will be processed as the while loop continues.
+ foreach (array_keys($module_data[$module]->requires) as $dependency) {
+ if (!isset($module_list[$dependency])) {
+ $module_list[$dependency] = 0;
+ }
+ }
+ }
+
+ if (!$module_list) {
+ // Nothing to do. All modules already enabled.
+ return TRUE;
+ }
+
+ // Sort the module list by pre-calculated weights.
+ arsort($module_list);
+ $module_list = array_keys($module_list);
+ }
+
+ // Required for module installation checks.
+ include_once DRUPAL_ROOT . '/includes/install.inc';
+
+ $modules_installed = array();
+ $modules_enabled = array();
+ foreach ($module_list as $module) {
+ // Only process modules that are not already enabled.
+ $existing = db_query("SELECT status FROM {system} WHERE type = :type AND name = :name", array(
+ ':type' => 'module',
+ ':name' => $module))
+ ->fetchObject();
+ if ($existing->status == 0) {
+ // Load the module's code.
+ drupal_load('module', $module);
+ module_load_install($module);
+
+ // Update the database and module list to reflect the new module. This
+ // needs to be done first so that the module's hook implementations,
+ // hook_schema() in particular, can be called while it is being
+ // installed.
+ db_update('system')
+ ->fields(array('status' => 1))
+ ->condition('type', 'module')
+ ->condition('name', $module)
+ ->execute();
+ // Refresh the module list to include it.
+ system_list_reset();
+ module_list(TRUE);
+ module_implements('', FALSE, TRUE);
+ _system_update_bootstrap_status();
+ // Update the registry to include it.
+ registry_update();
+ // Refresh the schema to include it.
+ drupal_get_schema(NULL, TRUE);
+ // Update the theme registry to include it.
+ drupal_theme_rebuild();
+ // Clear entity cache.
+ entity_info_cache_clear();
+
+ // Now install the module if necessary.
+ if (drupal_get_installed_schema_version($module, TRUE) == SCHEMA_UNINSTALLED) {
+ drupal_install_schema($module);
+
+ // Set the schema version to the number of the last update provided
+ // by the module.
+ $versions = drupal_get_schema_versions($module);
+ $version = $versions ? max($versions) : SCHEMA_INSTALLED;
+
+ // If the module has no current updates, but has some that were
+ // previously removed, set the version to the value of
+ // hook_update_last_removed().
+ if ($last_removed = module_invoke($module, 'update_last_removed')) {
+ $version = max($version, $last_removed);
+ }
+ drupal_set_installed_schema_version($module, $version);
+ // Allow the module to perform install tasks.
+ module_invoke($module, 'install');
+ // Record the fact that it was installed.
+ $modules_installed[] = $module;
+ watchdog('system', '%module module installed.', array('%module' => $module), WATCHDOG_INFO);
+ }
+
+ // Enable the module.
+ module_invoke($module, 'enable');
+
+ // Record the fact that it was enabled.
+ $modules_enabled[] = $module;
+ watchdog('system', '%module module enabled.', array('%module' => $module), WATCHDOG_INFO);
+ }
+ }
+
+ // If any modules were newly installed, invoke hook_modules_installed().
+ if (!empty($modules_installed)) {
+ module_invoke_all('modules_installed', $modules_installed);
+ }
+
+ // If any modules were newly enabled, invoke hook_modules_enabled().
+ if (!empty($modules_enabled)) {
+ module_invoke_all('modules_enabled', $modules_enabled);
+ }
+
+ return TRUE;
+}
+
+/**
+ * Disables a given set of modules.
+ *
+ * @param $module_list
+ * An array of module names.
+ * @param $disable_dependents
+ * If TRUE, dependent modules will automatically be added and disabled in the
+ * correct order. This incurs a significant performance cost, so use FALSE
+ * if you know $module_list is already complete and in the correct order.
+ */
+function module_disable($module_list, $disable_dependents = TRUE) {
+ if ($disable_dependents) {
+ // Get all module data so we can find dependents and sort.
+ $module_data = system_rebuild_module_data();
+ // Create an associative array with weights as values.
+ $module_list = array_flip(array_values($module_list));
+
+ $profile = drupal_get_profile();
+ while (list($module) = each($module_list)) {
+ if (!isset($module_data[$module]) || !$module_data[$module]->status) {
+ // This module doesn't exist or is already disabled, skip it.
+ unset($module_list[$module]);
+ continue;
+ }
+ $module_list[$module] = $module_data[$module]->sort;
+
+ // Add dependent modules to the list, with a placeholder weight.
+ // The new modules will be processed as the while loop continues.
+ foreach ($module_data[$module]->required_by as $dependent => $dependent_data) {
+ if (!isset($module_list[$dependent]) && $dependent != $profile) {
+ $module_list[$dependent] = 0;
+ }
+ }
+ }
+
+ // Sort the module list by pre-calculated weights.
+ asort($module_list);
+ $module_list = array_keys($module_list);
+ }
+
+ $invoke_modules = array();
+
+ foreach ($module_list as $module) {
+ if (module_exists($module)) {
+ // Check if node_access table needs rebuilding.
+ if (!node_access_needs_rebuild() && module_hook($module, 'node_grants')) {
+ node_access_needs_rebuild(TRUE);
+ }
+
+ module_load_install($module);
+ module_invoke($module, 'disable');
+ db_update('system')
+ ->fields(array('status' => 0))
+ ->condition('type', 'module')
+ ->condition('name', $module)
+ ->execute();
+ $invoke_modules[] = $module;
+ watchdog('system', '%module module disabled.', array('%module' => $module), WATCHDOG_INFO);
+ }
+ }
+
+ if (!empty($invoke_modules)) {
+ // Refresh the module list to exclude the disabled modules.
+ system_list_reset();
+ module_list(TRUE);
+ module_implements('', FALSE, TRUE);
+ entity_info_cache_clear();
+ // Invoke hook_modules_disabled before disabling modules,
+ // so we can still call module hooks to get information.
+ module_invoke_all('modules_disabled', $invoke_modules);
+ // Update the registry to remove the newly-disabled module.
+ registry_update();
+ _system_update_bootstrap_status();
+ // Update the theme registry to remove the newly-disabled module.
+ drupal_theme_rebuild();
+ }
+
+ // If there remains no more node_access module, rebuilding will be
+ // straightforward, we can do it right now.
+ if (node_access_needs_rebuild() && count(module_implements('node_grants')) == 0) {
+ node_access_rebuild();
+ }
+}
+
+/**
+ * @defgroup hooks Hooks
+ * @{
+ * Allow modules to interact with the Drupal core.
+ *
+ * Drupal's module system is based on the concept of "hooks". A hook is a PHP
+ * function that is named foo_bar(), where "foo" is the name of the module
+ * (whose filename is thus foo.module) and "bar" is the name of the hook. Each
+ * hook has a defined set of parameters and a specified result type.
+ *
+ * To extend Drupal, a module need simply implement a hook. When Drupal wishes
+ * to allow intervention from modules, it determines which modules implement a
+ * hook and calls that hook in all enabled modules that implement it.
+ *
+ * The available hooks to implement are explained here in the Hooks section of
+ * the developer documentation. The string "hook" is used as a placeholder for
+ * the module name in the hook definitions. For example, if the module file is
+ * called example.module, then hook_help() as implemented by that module would
+ * be defined as example_help().
+ *
+ * The example functions included are not part of the Drupal core, they are
+ * just models that you can modify. Only the hooks implemented within modules
+ * are executed when running Drupal.
+ *
+ * @see themeable
+ * @see callbacks
+ */
+
+ /**
+ * @defgroup callbacks Callbacks
+ * @{
+ * Callback function signatures.
+ *
+ * Drupal's API sometimes uses callback functions to allow you to define how
+ * some type of processing happens. A callback is a function with a defined
+ * signature, which you define in a module. Then you pass the function name as
+ * a parameter to a Drupal API function or return it as part of a hook
+ * implementation return value, and your function is called at an appropriate
+ * time. For instance, when setting up batch processing you might need to
+ * provide a callback function for each processing step and/or a callback for
+ * when processing is finished; you would do that by defining these functions
+ * and passing their names into the batch setup function.
+ *
+ * Callback function signatures, like hook definitions, are described by
+ * creating and documenting dummy functions in a *.api.php file; normally, the
+ * dummy callback function's name should start with "callback_", and you should
+ * document the parameters and return value and provide a sample function body.
+ * Then your API documentation can refer to this callback function in its
+ * documentation. A user of your API can usually name their callback function
+ * anything they want, although a standard name would be to replace "callback_"
+ * with the module name.
+ *
+ * @see hooks
+ * @see themeable
+ *
+ * @}
+ */
+
+/**
+ * Determines whether a module implements a hook.
+ *
+ * @param $module
+ * The name of the module (without the .module extension).
+ * @param $hook
+ * The name of the hook (e.g. "help" or "menu").
+ *
+ * @return
+ * TRUE if the module is both installed and enabled, and the hook is
+ * implemented in that module.
+ */
+function module_hook($module, $hook) {
+ $function = $module . '_' . $hook;
+ if (function_exists($function)) {
+ return TRUE;
+ }
+ // If the hook implementation does not exist, check whether it may live in an
+ // optional include file registered via hook_hook_info().
+ $hook_info = module_hook_info();
+ if (isset($hook_info[$hook]['group'])) {
+ module_load_include('inc', $module, $module . '.' . $hook_info[$hook]['group']);
+ if (function_exists($function)) {
+ return TRUE;
+ }
+ }
+ return FALSE;
+}
+
+/**
+ * Determines which modules are implementing a hook.
+ *
+ * @param $hook
+ * The name of the hook (e.g. "help" or "menu").
+ * @param $sort
+ * By default, modules are ordered by weight and filename, settings this option
+ * to TRUE, module list will be ordered by module name.
+ * @param $reset
+ * For internal use only: Whether to force the stored list of hook
+ * implementations to be regenerated (such as after enabling a new module,
+ * before processing hook_enable).
+ *
+ * @return
+ * An array with the names of the modules which are implementing this hook.
+ *
+ * @see module_implements_write_cache()
+ */
+function module_implements($hook, $sort = FALSE, $reset = FALSE) {
+ // Use the advanced drupal_static() pattern, since this is called very often.
+ static $drupal_static_fast;
+ if (!isset($drupal_static_fast)) {
+ $drupal_static_fast['implementations'] = &drupal_static(__FUNCTION__);
+ }
+ $implementations = &$drupal_static_fast['implementations'];
+
+ // We maintain a persistent cache of hook implementations in addition to the
+ // static cache to avoid looping through every module and every hook on each
+ // request. Benchmarks show that the benefit of this caching outweighs the
+ // additional database hit even when using the default database caching
+ // backend and only a small number of modules are enabled. The cost of the
+ // cache_get() is more or less constant and reduced further when non-database
+ // caching backends are used, so there will be more significant gains when a
+ // large number of modules are installed or hooks invoked, since this can
+ // quickly lead to module_hook() being called several thousand times
+ // per request.
+ if ($reset) {
+ $implementations = array();
+ cache_set('module_implements', array(), 'cache_bootstrap');
+ drupal_static_reset('module_hook_info');
+ drupal_static_reset('drupal_alter');
+ cache_clear_all('hook_info', 'cache_bootstrap');
+ return;
+ }
+
+ // Fetch implementations from cache.
+ if (empty($implementations)) {
+ $implementations = cache_get('module_implements', 'cache_bootstrap');
+ if ($implementations === FALSE) {
+ $implementations = array();
+ }
+ else {
+ $implementations = $implementations->data;
+ }
+ }
+
+ if (!isset($implementations[$hook])) {
+ // The hook is not cached, so ensure that whether or not it has
+ // implementations, that the cache is updated at the end of the request.
+ $implementations['#write_cache'] = TRUE;
+ $hook_info = module_hook_info();
+ $implementations[$hook] = array();
+ $list = module_list(FALSE, FALSE, $sort);
+ foreach ($list as $module) {
+ $include_file = isset($hook_info[$hook]['group']) && module_load_include('inc', $module, $module . '.' . $hook_info[$hook]['group']);
+ // Since module_hook() may needlessly try to load the include file again,
+ // function_exists() is used directly here.
+ if (function_exists($module . '_' . $hook)) {
+ $implementations[$hook][$module] = $include_file ? $hook_info[$hook]['group'] : FALSE;
+ }
+ }
+ // Allow modules to change the weight of specific implementations but avoid
+ // an infinite loop.
+ if ($hook != 'module_implements_alter') {
+ drupal_alter('module_implements', $implementations[$hook], $hook);
+ }
+ }
+ else {
+ foreach ($implementations[$hook] as $module => $group) {
+ // If this hook implementation is stored in a lazy-loaded file, so include
+ // that file first.
+ if ($group) {
+ module_load_include('inc', $module, "$module.$group");
+ }
+ // It is possible that a module removed a hook implementation without the
+ // implementations cache being rebuilt yet, so we check whether the
+ // function exists on each request to avoid undefined function errors.
+ // Since module_hook() may needlessly try to load the include file again,
+ // function_exists() is used directly here.
+ if (!function_exists($module . '_' . $hook)) {
+ // Clear out the stale implementation from the cache and force a cache
+ // refresh to forget about no longer existing hook implementations.
+ unset($implementations[$hook][$module]);
+ $implementations['#write_cache'] = TRUE;
+ }
+ }
+ }
+
+ return array_keys($implementations[$hook]);
+}
+
+/**
+ * Retrieves a list of hooks that are declared through hook_hook_info().
+ *
+ * @return
+ * An associative array whose keys are hook names and whose values are an
+ * associative array containing a group name. The structure of the array
+ * is the same as the return value of hook_hook_info().
+ *
+ * @see hook_hook_info()
+ */
+function module_hook_info() {
+ // This function is indirectly invoked from bootstrap_invoke_all(), in which
+ // case common.inc, subsystems, and modules are not loaded yet, so it does not
+ // make sense to support hook groups resp. lazy-loaded include files prior to
+ // full bootstrap.
+ if (drupal_bootstrap(NULL, FALSE) != DRUPAL_BOOTSTRAP_FULL) {
+ return array();
+ }
+ $hook_info = &drupal_static(__FUNCTION__);
+
+ if (!isset($hook_info)) {
+ $hook_info = array();
+ $cache = cache_get('hook_info', 'cache_bootstrap');
+ if ($cache === FALSE) {
+ // Rebuild the cache and save it.
+ // We can't use module_invoke_all() here or it would cause an infinite
+ // loop.
+ foreach (module_list() as $module) {
+ $function = $module . '_hook_info';
+ if (function_exists($function)) {
+ $result = $function();
+ if (isset($result) && is_array($result)) {
+ $hook_info = array_merge_recursive($hook_info, $result);
+ }
+ }
+ }
+ // We can't use drupal_alter() for the same reason as above.
+ foreach (module_list() as $module) {
+ $function = $module . '_hook_info_alter';
+ if (function_exists($function)) {
+ $function($hook_info);
+ }
+ }
+ cache_set('hook_info', $hook_info, 'cache_bootstrap');
+ }
+ else {
+ $hook_info = $cache->data;
+ }
+ }
+
+ return $hook_info;
+}
+
+/**
+ * Writes the hook implementation cache.
+ *
+ * @see module_implements()
+ */
+function module_implements_write_cache() {
+ $implementations = &drupal_static('module_implements');
+ if (isset($implementations['#write_cache'])) {
+ unset($implementations['#write_cache']);
+ cache_set('module_implements', $implementations, 'cache_bootstrap');
+ }
+}
+
+/**
+ * Invokes a hook in a particular module.
+ *
+ * All arguments are passed by value. Use drupal_alter() if you need to pass
+ * arguments by reference.
+ *
+ * @param $module
+ * The name of the module (without the .module extension).
+ * @param $hook
+ * The name of the hook to invoke.
+ * @param ...
+ * Arguments to pass to the hook implementation.
+ *
+ * @return
+ * The return value of the hook implementation.
+ *
+ * @see drupal_alter()
+ */
+function module_invoke($module, $hook) {
+ $args = func_get_args();
+ // Remove $module and $hook from the arguments.
+ unset($args[0], $args[1]);
+ if (module_hook($module, $hook)) {
+ return call_user_func_array($module . '_' . $hook, $args);
+ }
+}
+
+/**
+ * Invokes a hook in all enabled modules that implement it.
+ *
+ * All arguments are passed by value. Use drupal_alter() if you need to pass
+ * arguments by reference.
+ *
+ * @param $hook
+ * The name of the hook to invoke.
+ * @param ...
+ * Arguments to pass to the hook.
+ *
+ * @return
+ * An array of return values of the hook implementations. If modules return
+ * arrays from their implementations, those are merged into one array.
+ *
+ * @see drupal_alter()
+ */
+function module_invoke_all($hook) {
+ $args = func_get_args();
+ // Remove $hook from the arguments.
+ unset($args[0]);
+ $return = array();
+ foreach (module_implements($hook) as $module) {
+ $function = $module . '_' . $hook;
+ if (function_exists($function)) {
+ $result = call_user_func_array($function, $args);
+ if (isset($result) && is_array($result)) {
+ $return = array_merge_recursive($return, $result);
+ }
+ elseif (isset($result)) {
+ $return[] = $result;
+ }
+ }
+ }
+
+ return $return;
+}
+
+/**
+ * @} End of "defgroup hooks".
+ */
+
+/**
+ * Returns an array of modules required by core.
+ */
+function drupal_required_modules() {
+ $files = drupal_system_listing('/^' . DRUPAL_PHP_FUNCTION_PATTERN . '\.info$/', 'modules', 'name', 0);
+ $required = array();
+
+ // An installation profile is required and one must always be loaded.
+ $required[] = drupal_get_profile();
+
+ foreach ($files as $name => $file) {
+ $info = drupal_parse_info_file($file->uri);
+ if (!empty($info) && !empty($info['required']) && $info['required']) {
+ $required[] = $name;
+ }
+ }
+
+ return $required;
+}
+
+/**
+ * Passes alterable variables to specific hook_TYPE_alter() implementations.
+ *
+ * This dispatch function hands off the passed-in variables to type-specific
+ * hook_TYPE_alter() implementations in modules. It ensures a consistent
+ * interface for all altering operations.
+ *
+ * A maximum of 2 alterable arguments is supported (a third is supported for
+ * legacy reasons, but should not be used in new code). In case more arguments
+ * need to be passed and alterable, modules provide additional variables
+ * assigned by reference in the last $context argument:
+ * @code
+ * $context = array(
+ * 'alterable' => &$alterable,
+ * 'unalterable' => $unalterable,
+ * 'foo' => 'bar',
+ * );
+ * drupal_alter('mymodule_data', $alterable1, $alterable2, $context);
+ * @endcode
+ *
+ * Note that objects are always passed by reference in PHP5. If it is absolutely
+ * required that no implementation alters a passed object in $context, then an
+ * object needs to be cloned:
+ * @code
+ * $context = array(
+ * 'unalterable_object' => clone $object,
+ * );
+ * drupal_alter('mymodule_data', $data, $context);
+ * @endcode
+ *
+ * @param $type
+ * A string describing the type of the alterable $data. 'form', 'links',
+ * 'node_content', and so on are several examples. Alternatively can be an
+ * array, in which case hook_TYPE_alter() is invoked for each value in the
+ * array, ordered first by module, and then for each module, in the order of
+ * values in $type. For example, when Form API is using drupal_alter() to
+ * execute both hook_form_alter() and hook_form_FORM_ID_alter()
+ * implementations, it passes array('form', 'form_' . $form_id) for $type.
+ * @param $data
+ * The variable that will be passed to hook_TYPE_alter() implementations to be
+ * altered. The type of this variable depends on the value of the $type
+ * argument. For example, when altering a 'form', $data will be a structured
+ * array. When altering a 'profile', $data will be an object.
+ * @param $context1
+ * (optional) An additional variable that is passed by reference.
+ * @param $context2
+ * (optional) An additional variable that is passed by reference. If more
+ * context needs to be provided to implementations, then this should be an
+ * associative array as described above.
+ * @param $context3
+ * (optional) An additional variable that is passed by reference. This
+ * parameter is deprecated and will not exist in Drupal 8; consequently, it
+ * should not be used for new Drupal 7 code either. It is here only for
+ * backwards compatibility with older code that passed additional arguments
+ * to drupal_alter().
+ */
+function drupal_alter($type, &$data, &$context1 = NULL, &$context2 = NULL, &$context3 = NULL) {
+ // Use the advanced drupal_static() pattern, since this is called very often.
+ static $drupal_static_fast;
+ if (!isset($drupal_static_fast)) {
+ $drupal_static_fast['functions'] = &drupal_static(__FUNCTION__);
+ }
+ $functions = &$drupal_static_fast['functions'];
+
+ // Most of the time, $type is passed as a string, so for performance,
+ // normalize it to that. When passed as an array, usually the first item in
+ // the array is a generic type, and additional items in the array are more
+ // specific variants of it, as in the case of array('form', 'form_FORM_ID').
+ if (is_array($type)) {
+ $cid = implode(',', $type);
+ $extra_types = $type;
+ $type = array_shift($extra_types);
+ // Allow if statements in this function to use the faster isset() rather
+ // than !empty() both when $type is passed as a string, or as an array with
+ // one item.
+ if (empty($extra_types)) {
+ unset($extra_types);
+ }
+ }
+ else {
+ $cid = $type;
+ }
+
+ // Some alter hooks are invoked many times per page request, so statically
+ // cache the list of functions to call, and on subsequent calls, iterate
+ // through them quickly.
+ if (!isset($functions[$cid])) {
+ $functions[$cid] = array();
+ $hook = $type . '_alter';
+ $modules = module_implements($hook);
+ if (!isset($extra_types)) {
+ // For the more common case of a single hook, we do not need to call
+ // function_exists(), since module_implements() returns only modules with
+ // implementations.
+ foreach ($modules as $module) {
+ $functions[$cid][] = $module . '_' . $hook;
+ }
+ }
+ else {
+ // For multiple hooks, we need $modules to contain every module that
+ // implements at least one of them.
+ $extra_modules = array();
+ foreach ($extra_types as $extra_type) {
+ $extra_modules = array_merge($extra_modules, module_implements($extra_type . '_alter'));
+ }
+ // If any modules implement one of the extra hooks that do not implement
+ // the primary hook, we need to add them to the $modules array in their
+ // appropriate order. module_implements() can only return ordered
+ // implementations of a single hook. To get the ordered implementations
+ // of multiple hooks, we mimic the module_implements() logic of first
+ // ordering by module_list(), and then calling
+ // drupal_alter('module_implements').
+ if (array_diff($extra_modules, $modules)) {
+ // Merge the arrays and order by module_list().
+ $modules = array_intersect(module_list(), array_merge($modules, $extra_modules));
+ // Since module_implements() already took care of loading the necessary
+ // include files, we can safely pass FALSE for the array values.
+ $implementations = array_fill_keys($modules, FALSE);
+ // Let modules adjust the order solely based on the primary hook. This
+ // ensures the same module order regardless of whether this if block
+ // runs. Calling drupal_alter() recursively in this way does not result
+ // in an infinite loop, because this call is for a single $type, so we
+ // won't end up in this code block again.
+ drupal_alter('module_implements', $implementations, $hook);
+ $modules = array_keys($implementations);
+ }
+ foreach ($modules as $module) {
+ // Since $modules is a merged array, for any given module, we do not
+ // know whether it has any particular implementation, so we need a
+ // function_exists().
+ $function = $module . '_' . $hook;
+ if (function_exists($function)) {
+ $functions[$cid][] = $function;
+ }
+ foreach ($extra_types as $extra_type) {
+ $function = $module . '_' . $extra_type . '_alter';
+ if (function_exists($function)) {
+ $functions[$cid][] = $function;
+ }
+ }
+ }
+ }
+ // Allow the theme to alter variables after the theme system has been
+ // initialized.
+ global $theme, $base_theme_info;
+ if (isset($theme)) {
+ $theme_keys = array();
+ foreach ($base_theme_info as $base) {
+ $theme_keys[] = $base->name;
+ }
+ $theme_keys[] = $theme;
+ foreach ($theme_keys as $theme_key) {
+ $function = $theme_key . '_' . $hook;
+ if (function_exists($function)) {
+ $functions[$cid][] = $function;
+ }
+ if (isset($extra_types)) {
+ foreach ($extra_types as $extra_type) {
+ $function = $theme_key . '_' . $extra_type . '_alter';
+ if (function_exists($function)) {
+ $functions[$cid][] = $function;
+ }
+ }
+ }
+ }
+ }
+ }
+
+ foreach ($functions[$cid] as $function) {
+ $function($data, $context1, $context2, $context3);
+ }
+}