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41 results

system.api.php

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  • webchick's avatar
    Issue #1037352 by jhodgdon: hook_permission() is missing doc about 'warning'.
    Angie Byron authored
    11a17706
    History
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    Assign users and groups as approvers for specific file changes. Learn more.
    system.api.php 172.46 KiB
    <?php
    
    /**
     * @file
     * Hooks provided by Drupal core and the System module.
     */
    
    /**
     * @addtogroup hooks
     * @{
     */
    
    /**
     * Defines one or more hooks that are exposed by a module.
     *
     * Normally hooks do not need to be explicitly defined. However, by declaring a
     * hook explicitly, a module may define a "group" for it. Modules that implement
     * a hook may then place their implementation in either $module.module or in
     * $module.$group.inc. If the hook is located in $module.$group.inc, then that
     * file will be automatically loaded when needed.
     * In general, hooks that are rarely invoked and/or are very large should be
     * placed in a separate include file, while hooks that are very short or very
     * frequently called should be left in the main module file so that they are
     * always available.
     *
     * @return
     *   An associative array whose keys are hook names and whose values are an
     *   associative array containing:
     *   - group: A string defining the group to which the hook belongs. The module
     *     system will determine whether a file with the name $module.$group.inc
     *     exists, and automatically load it when required.
     *
     * See system_hook_info() for all hook groups defined by Drupal core.
     *
     * @see hook_hook_info_alter().
     */
    function hook_hook_info() {
      $hooks['token_info'] = array(
        'group' => 'tokens',
      );
      $hooks['tokens'] = array(
        'group' => 'tokens',
      );
      return $hooks;
    }
    
    /**
     * Alter information from hook_hook_info().
     *
     * @param $hooks
     *   Information gathered by module_hook_info() from other modules'
     *   implementations of hook_hook_info(). Alter this array directly.
     *   See hook_hook_info() for information on what this may contain.
     */
    function hook_hook_info_alter(&$hooks) {
      // Our module wants to completely override the core tokens, so make
      // sure the core token hooks are not found.
      $hooks['token_info']['group'] = 'mytokens';
      $hooks['tokens']['group'] = 'mytokens';
    }
    
    /**
     * Inform the base system and the Field API about one or more entity types.
     *
     * Inform the system about one or more entity types (i.e., object types that
     * can be loaded via entity_load() and, optionally, to which fields can be
     * attached).
     *
     * @return
     *   An array whose keys are entity type names and whose values identify
     *   properties of those types that the system needs to know about:
     *   - label: The human-readable name of the type.
     *   - controller class: The name of the class that is used to load the objects.
     *     The class has to implement the DrupalEntityControllerInterface interface.
     *     Leave blank to use the DrupalDefaultEntityController implementation.
     *   - base table: (used by DrupalDefaultEntityController) The name of the
     *     entity type's base table.
     *   - static cache: (used by DrupalDefaultEntityController) FALSE to disable
     *     static caching of entities during a page request. Defaults to TRUE.
     *   - field cache: (used by Field API loading and saving of field data) FALSE
     *     to disable Field API's persistent cache of field data. Only recommended
     *     if a higher level persistent cache is available for the entity type.
     *     Defaults to TRUE.
     *   - load hook: The name of the hook which should be invoked by
     *     DrupalDefaultEntityController:attachLoad(), for example 'node_load'.
     *   - uri callback: A function taking an entity as argument and returning the
     *     uri elements of the entity, e.g. 'path' and 'options'. The actual entity
     *     uri can be constructed by passing these elements to url().
     *   - label callback: (optional) A function taking an entity as argument and
     *     returning the label of the entity. The entity label is the main string
     *     associated with an entity; for example, the title of a node or the
     *     subject of a comment. If there is an entity object property that defines
     *     the label, use the 'label' element of the 'entity keys' return
     *     value component to provide this information (see below). If more complex
     *     logic is needed to determine the label of an entity, you can instead
     *     specify a callback function here, which will be called to determine the
     *     entity label. See also the entity_label() function, which implements this
     *     logic.
     *   - fieldable: Set to TRUE if you want your entity type to be fieldable.
     *   - translation: An associative array of modules registered as field
     *     translation handlers. Array keys are the module names, array values
     *     can be any data structure the module uses to provide field translation.
     *     Any empty value disallows the module to appear as a translation handler.
     *   - entity keys: An array describing how the Field API can extract the
     *     information it needs from the objects of the type. Elements:
     *     - id: The name of the property that contains the primary id of the
     *       entity. Every entity object passed to the Field API must have this
     *       property and its value must be numeric.
     *     - revision: The name of the property that contains the revision id of
     *       the entity. The Field API assumes that all revision ids are unique
     *       across all entities of a type. This entry can be omitted if the
     *       entities of this type are not versionable.
     *     - bundle: The name of the property that contains the bundle name for the
     *       entity. The bundle name defines which set of fields are attached to
     *       the entity (e.g. what nodes call "content type"). This entry can be
     *       omitted if this entity type exposes a single bundle (all entities have
     *       the same collection of fields). The name of this single bundle will be
     *       the same as the entity type.
     *     - label: The name of the property that contains the entity label. For
     *       example, if the entity's label is located in $entity->subject, then
     *       'subject' should be specified here. If complex logic is required to
     *       build the label, a 'label callback' should be defined instead (see
     *       the 'label callback' section above for details).
     *   - bundle keys: An array describing how the Field API can extract the
     *     information it needs from the bundle objects for this type. This entry
     *     is required if the 'path' provided in the 'bundles'/'admin' section
     *     identifies the bundle using a named menu placeholder whose loader
     *     callback returns an object (e.g., $vocabulary for taxonomy terms, or
     *     $node_type for nodes). If the path does not include the bundle, or the
     *     bundle is just a string rather than an automatically loaded object, then
     *     this can be omitted. Elements:
     *     - bundle: The name of the property of the bundle object that contains
     *       the name of the bundle object.
     *   - bundles: An array describing all bundles for this object type. Keys are
     *     bundles machine names, as found in the objects' 'bundle' property
     *     (defined in the 'entity keys' entry above). Elements:
     *     - label: The human-readable name of the bundle.
     *     - uri callback: Same as the 'uri callback' key documented above for the
     *       entity type, but for the bundle only. When determining the URI of an
     *       entity, if a 'uri callback' is defined for both the entity type and
     *       the bundle, the one for the bundle is used.
     *     - admin: An array of information that allows Field UI pages to attach
     *       themselves to the existing administration pages for the bundle.
     *       Elements:
     *       - path: the path of the bundle's main administration page, as defined
     *         in hook_menu(). If the path includes a placeholder for the bundle,
     *         the 'bundle argument' and 'real path' keys below are required.
     *       - bundle argument: The position of the bundle placeholder in 'path', if
     *         any.
     *       - real path: The actual path (no placeholder) of the bundle's main
     *         administration page. This will be used to generate links.
     *       - access callback: As in hook_menu(). 'user_access' will be assumed if
     *         no value is provided.
     *       - access arguments: As in hook_menu().
     *   - view modes: An array describing the view modes for the entity type. View
     *     modes let entities be displayed differently depending on the context.
     *     For instance, a node can be displayed differently on its own page
     *     ('full' mode), on the home page or taxonomy listings ('teaser' mode), or
     *     in an RSS feed ('rss' mode). Modules taking part in the display of the
     *     entity (notably the Field API) can adjust their behavior depending on
     *     the requested view mode. An additional 'default' view mode is available
     *     for all entity types. This view mode is not intended for actual entity
     *     display, but holds default display settings. For each available view
     *     mode, administrators can configure whether it should use its own set of
     *     field display settings, or just replicate the settings of the 'default'
     *     view mode, thus reducing the amount of display configurations to keep
     *     track of. Keys of the array are view mode names. Each view mode is
     *     described by an array with the following key/value pairs:
     *     - label: The human-readable name of the view mode
     *     - custom settings: A boolean specifying whether the view mode should by
     *       default use its own custom field display settings. If FALSE, entities
     *       displayed in this view mode will reuse the 'default' display settings
     *       by default (e.g. right after the module exposing the view mode is
     *       enabled), but administrators can later use the Field UI to apply custom
     *       display settings specific to the view mode.
     *
     * @see entity_load()
     * @see hook_entity_info_alter()
     */
    function hook_entity_info() {
      $return = array(
        'node' => array(
          'label' => t('Node'),
          'controller class' => 'NodeController',
          'base table' => 'node',
          'revision table' => 'node_revision',
          'uri callback' => 'node_uri',
          'fieldable' => TRUE,
          'translation' => array(
            'locale' => TRUE,
          ),
          'entity keys' => array(
            'id' => 'nid',
            'revision' => 'vid',
            'bundle' => 'type',
          ),
          'bundle keys' => array(
            'bundle' => 'type',
          ),
          'bundles' => array(),
          'view modes' => array(
            'full' => array(
              'label' => t('Full content'),
              'custom settings' => FALSE,
            ),
            'teaser' => array(
              'label' => t('Teaser'),
              'custom settings' => TRUE,
            ),
            'rss' => array(
              'label' => t('RSS'),
              'custom settings' => FALSE,
            ),
          ),
        ),
      );
    
      // Search integration is provided by node.module, so search-related
      // view modes for nodes are defined here and not in search.module.
      if (module_exists('search')) {
        $return['node']['view modes'] += array(
          'search_index' => array(
            'label' => t('Search index'),
            'custom settings' => FALSE,
          ),
          'search_result' => array(
            'label' => t('Search result'),
            'custom settings' => FALSE,
          ),
        );
      }
    
      // Bundles must provide a human readable name so we can create help and error
      // messages, and the path to attach Field admin pages to.
      foreach (node_type_get_names() as $type => $name) {
        $return['node']['bundles'][$type] = array(
          'label' => $name,
          'admin' => array(
            'path' => 'admin/structure/types/manage/%node_type',
            'real path' => 'admin/structure/types/manage/' . str_replace('_', '-', $type),
            'bundle argument' => 4,
            'access arguments' => array('administer content types'),
          ),
        );
      }
    
      return $return;
    }
    
    /**
     * Alter the entity info.
     *
     * Modules may implement this hook to alter the information that defines an
     * entity. All properties that are available in hook_entity_info() can be
     * altered here.
     *
     * @param $entity_info
     *   The entity info array, keyed by entity name.
     *
     * @see hook_entity_info()
     */
    function hook_entity_info_alter(&$entity_info) {
      // Set the controller class for nodes to an alternate implementation of the
      // DrupalEntityController interface.
      $entity_info['node']['controller class'] = 'MyCustomNodeController';
    }
    
    /**
     * Act on entities when loaded.
     *
     * This is a generic load hook called for all entity types loaded via the
     * entity API.
     *
     * @param $entities
     *   The entities keyed by entity ID.
     * @param $type
     *   The type of entities being loaded (i.e. node, user, comment).
     */
    function hook_entity_load($entities, $type) {
      foreach ($entities as $entity) {
        $entity->foo = mymodule_add_something($entity, $type);
      }
    }
    
    /**
     * Act on an entity before it is about to be created or updated.
     *
     * @param $entity
     *   The entity object.
     * @param $type
     *   The type of entity being saved (i.e. node, user, comment).
     */
    function hook_entity_presave($entity, $type) {
      $entity->changed = REQUEST_TIME;
    }
    
    /**
     * Act on entities when inserted.
     *
     * @param $entity
     *   The entity object.
     * @param $type
     *   The type of entity being inserted (i.e. node, user, comment).
     */
    function hook_entity_insert($entity, $type) {
      // Insert the new entity into a fictional table of all entities.
      $info = entity_get_info($type);
      list($id) = entity_extract_ids($type, $entity);
      db_insert('example_entity')
        ->fields(array(
          'type' => $type,
          'id' => $id,
          'created' => REQUEST_TIME,
          'updated' => REQUEST_TIME,
        ))
        ->execute();
    }
    
    /**
     * Act on entities when updated.
     *
     * @param $entity
     *   The entity object.
     * @param $type
     *   The type of entity being updated (i.e. node, user, comment).
     */
    function hook_entity_update($entity, $type) {
      // Update the entity's entry in a fictional table of all entities.
      $info = entity_get_info($type);
      list($id) = entity_extract_ids($type, $entity);
      db_update('example_entity')
        ->fields(array(
          'updated' => REQUEST_TIME,
        ))
        ->condition('type', $type)
        ->condition('id', $id)
        ->execute();
    }
    
    /**
     * Act on entities when deleted.
     *
     * @param $entity
     *   The entity object.
     * @param $type
     *   The type of entity being deleted (i.e. node, user, comment).
     */
    function hook_entity_delete($entity, $type) {
      // Delete the entity's entry from a fictional table of all entities.
      $info = entity_get_info($type);
      list($id) = entity_extract_ids($type, $entity);
      db_delete('example_entity')
        ->condition('type', $type)
        ->condition('id', $id)
        ->execute();
    }
    
    /**
     * Alter or execute an EntityFieldQuery.
     *
     * @param EntityFieldQuery $query
     *   An EntityFieldQuery. One of the most important properties to be changed is
     *   EntityFieldQuery::executeCallback. If this is set to an existing function,
     *   this function will get the query as its single argument and its result
     *   will be the returned as the result of EntityFieldQuery::execute(). This can
     *   be used to change the behavior of EntityFieldQuery entirely. For example,
     *   the default implementation can only deal with one field storage engine, but
     *   it is possible to write a module that can query across field storage
     *   engines. Also, the default implementation presumes entities are stored in
     *   SQL, but the execute callback could instead query any other entity storage,
     *   local or remote.
     *
     *   Note the $query->altered attribute which is TRUE in case the query has
     *   already been altered once. This happens with cloned queries.
     *   If there is a pager, then such a cloned query will be executed to count
     *   all elements. This query can be detected by checking for
     *   ($query->pager && $query->count), allowing the driver to return 0 from
     *   the count query and disable the pager.
     */
    function hook_entity_query_alter($query) {
      $query->executeCallback = 'my_module_query_callback';
    }
    
    /**
     * Act on entities being assembled before rendering.
     *
     * @param $entity
     *   The entity object.
     * @param $type
     *   The type of entity being rendered (i.e. node, user, comment).
     * @param $view_mode
     *   The view mode the entity is rendered in.
     * @param $langcode
     *   The language code used for rendering.
     *
     * The module may add elements to $entity->content prior to rendering. The
     * structure of $entity->content is a renderable array as expected by
     * drupal_render().
     *
     * @see hook_entity_view_alter()
     * @see hook_comment_view()
     * @see hook_node_view()
     * @see hook_user_view()
     */
    function hook_entity_view($entity, $type, $view_mode, $langcode) {
      $entity->content['my_additional_field'] = array(
        '#markup' => $additional_field,
        '#weight' => 10,
        '#theme' => 'mymodule_my_additional_field',
      );
    }
    
    /**
     * Alter the results of ENTITY_view().
     *
     * This hook is called after the content has been assembled in a structured
     * array and may be used for doing processing which requires that the complete
     * entity content structure has been built.
     *
     * If a module wishes to act on the rendered HTML of the entity rather than the
     * structured content array, it may use this hook to add a #post_render
     * callback. Alternatively, it could also implement hook_preprocess_ENTITY().
     * See drupal_render() and theme() for details.
     *
     * @param $build
     *   A renderable array representing the entity content.
     * @param $type
     *   The type of entity being rendered (i.e. node, user, comment).
     *
     * @see hook_entity_view()
     * @see hook_comment_view_alter()
     * @see hook_node_view_alter()
     * @see hook_taxonomy_term_view_alter()
     * @see hook_user_view_alter()
     */
    function hook_entity_view_alter(&$build, $type) {
      if ($build['#view_mode'] == 'full' && isset($build['an_additional_field'])) {
        // Change its weight.
        $build['an_additional_field']['#weight'] = -10;
    
        // Add a #post_render callback to act on the rendered HTML of the entity.
        $build['#post_render'][] = 'my_module_node_post_render';
      }
    }
    
    /**
     * Define administrative paths.
     *
     * Modules may specify whether or not the paths they define in hook_menu() are
     * to be considered administrative. Other modules may use this information to
     * display those pages differently (e.g. in a modal overlay, or in a different
     * theme).
     *
     * To change the administrative status of menu items defined in another module's
     * hook_menu(), modules should implement hook_admin_paths_alter().
     *
     * @return
     *   An associative array. For each item, the key is the path in question, in
     *   a format acceptable to drupal_match_path(). The value for each item should
     *   be TRUE (for paths considered administrative) or FALSE (for non-
     *   administrative paths).
     *
     * @see hook_menu()
     * @see drupal_match_path()
     * @see hook_admin_paths_alter()
     */
    function hook_admin_paths() {
      $paths = array(
        'mymodule/*/add' => TRUE,
        'mymodule/*/edit' => TRUE,
      );
      return $paths;
    }
    
    /**
     * Redefine administrative paths defined by other modules.
     *
     * @param $paths
     *   An associative array of administrative paths, as defined by implementations
     *   of hook_admin_paths().
     *
     * @see hook_admin_paths()
     */
    function hook_admin_paths_alter(&$paths) {
      // Treat all user pages as administrative.
      $paths['user'] = TRUE;
      $paths['user/*'] = TRUE;
      // Treat the forum topic node form as a non-administrative page.
      $paths['node/add/forum'] = FALSE;
    }
    
    /**
     * Act on entities as they are being prepared for view.
     *
     * Allows you to operate on multiple entities as they are being prepared for
     * view. Only use this if attaching the data during the entity_load() phase
     * is not appropriate, for example when attaching other 'entity' style objects.
     *
     * @param $entities
     *   The entities keyed by entity ID.
     * @param $type
     *   The type of entities being loaded (i.e. node, user, comment).
     */
    function hook_entity_prepare_view($entities, $type) {
      // Load a specific node into the user object for later theming.
      if ($type == 'user') {
        $nodes = mymodule_get_user_nodes(array_keys($entities));
        foreach ($entities as $uid => $entity) {
          $entity->user_node = $nodes[$uid];
        }
      }
    }
    
    /**
     * Perform periodic actions.
     *
     * This hook will only be called if cron.php is run (e.g. by crontab).
     *
     * Modules that require some commands to be executed periodically can
     * implement hook_cron(). The engine will then call the hook whenever a cron
     * run happens, as defined by the administrator. Typical tasks managed by
     * hook_cron() are database maintenance, backups, recalculation of settings
     * or parameters, automated mailing, and retrieving remote data.
     *
     * Short-running or non-resource-intensive tasks can be executed directly in
     * the hook_cron() implementation.
     *
     * Long-running tasks and tasks that could time out, such as retrieving remote
     * data, sending email, and intensive file tasks, should use the queue API
     * instead of executing the tasks directly. To do this, first define one or
     * more queues via hook_cron_queue_info(). Then, add items that need to be
     * processed to the defined queues.
     */
    function hook_cron() {
      // Short-running operation example, not using a queue:
      // Delete all expired records since the last cron run.
      $expires = variable_get('mymodule_cron_last_run', REQUEST_TIME);
      db_delete('mymodule_table')
        ->condition('expires', $expires, '>=')
        ->execute();
      variable_set('mymodule_cron_last_run', REQUEST_TIME);
    
      // Long-running operation example, leveraging a queue:
      // Fetch feeds from other sites.
      $result = db_query('SELECT * FROM {aggregator_feed} WHERE checked + refresh < :time AND refresh != :never', array(
        ':time' => REQUEST_TIME,
        ':never' => AGGREGATOR_CLEAR_NEVER,
      ));
      $queue = DrupalQueue::get('aggregator_feeds');
      foreach ($result as $feed) {
        $queue->createItem($feed);
      }
    }
    
    /**
     * Declare queues holding items that need to be run periodically.
     *
     * While there can be only one hook_cron() process running at the same time,
     * there can be any number of processes defined here running. Because of
     * this, long running tasks are much better suited for this API. Items queued
     * in hook_cron() might be processed in the same cron run if there are not many
     * items in the queue, otherwise it might take several requests, which can be
     * run in parallel.
     *
     * @return
     *   An associative array where the key is the queue name and the value is
     *   again an associative array. Possible keys are:
     *   - 'worker callback': The name of the function to call. It will be called
     *     with one argument, the item created via DrupalQueue::createItem() in
     *     hook_cron().
     *   - 'time': (optional) How much time Drupal should spend on calling this
     *     worker in seconds. Defaults to 15.
     *
     * @see hook_cron()
     * @see hook_cron_queue_info_alter()
     */
    function hook_cron_queue_info() {
      $queues['aggregator_feeds'] = array(
        'worker callback' => 'aggregator_refresh',
        'time' => 60,
      );
      return $queues;
    }
    
    /**
     * Alter cron queue information before cron runs.
     *
     * Called by drupal_cron_run() to allow modules to alter cron queue settings
     * before any jobs are processesed.
     *
     * @param array $queues
     *   An array of cron queue information.
     *
     * @see hook_cron_queue_info()
     * @see drupal_cron_run()
     */
    function hook_cron_queue_info_alter(&$queues) {
      // This site has many feeds so let's spend 90 seconds on each cron run
      // updating feeds instead of the default 60.
      $queues['aggregator_feeds']['time'] = 90;
    }
    
    /**
     * Allows modules to declare their own Forms API element types and specify their
     * default values.
     *
     * This hook allows modules to declare their own form element types and to
     * specify their default values. The values returned by this hook will be
     * merged with the elements returned by hook_form() implementations and so
     * can return defaults for any Form APIs keys in addition to those explicitly
     * mentioned below.
     *
     * Each of the form element types defined by this hook is assumed to have
     * a matching theme function, e.g. theme_elementtype(), which should be
     * registered with hook_theme() as normal.
     *
     * For more information about custom element types see the explanation at
     * http://drupal.org/node/169815.
     *
     * @return
     *  An associative array describing the element types being defined. The array
     *  contains a sub-array for each element type, with the machine-readable type
     *  name as the key. Each sub-array has a number of possible attributes:
     *  - "#input": boolean indicating whether or not this element carries a value
     *    (even if it's hidden).
     *  - "#process": array of callback functions taking $element, $form_state,
     *    and $complete_form.
     *  - "#after_build": array of callback functions taking $element and $form_state.
     *  - "#validate": array of callback functions taking $form and $form_state.
     *  - "#element_validate": array of callback functions taking $element and
     *    $form_state.
     *  - "#pre_render": array of callback functions taking $element and $form_state.
     *  - "#post_render": array of callback functions taking $element and $form_state.
     *  - "#submit": array of callback functions taking $form and $form_state.
     *  - "#title_display": optional string indicating if and how #title should be
     *    displayed, see theme_form_element() and theme_form_element_label().
     *
     * @see hook_element_info_alter()
     * @see system_element_info()
     */
    function hook_element_info() {
      $types['filter_format'] = array(
        '#input' => TRUE,
      );
      return $types;
    }
    
    /**
     * Alter the element type information returned from modules.
     *
     * A module may implement this hook in order to alter the element type defaults
     * defined by a module.
     *
     * @param &$type
     *   All element type defaults as collected by hook_element_info().
     *
     * @see hook_element_info()
     */
    function hook_element_info_alter(&$type) {
      // Decrease the default size of textfields.
      if (isset($type['textfield']['#size'])) {
        $type['textfield']['#size'] = 40;
      }
    }
    
    /**
     * Perform cleanup tasks.
     *
     * This hook is run at the end of each page request. It is often used for
     * page logging and specialized cleanup. This hook MUST NOT print anything.
     *
     * Only use this hook if your code must run even for cached page views.
     * If you have code which must run once on all non cached pages, use
     * hook_init instead. Thats the usual case. If you implement this hook
     * and see an error like 'Call to undefined function', it is likely that
     * you are depending on the presence of a module which has not been loaded yet.
     * It is not loaded because Drupal is still in bootstrap mode.
     *
     * @param $destination
     *   If this hook is invoked as part of a drupal_goto() call, then this argument
     *   will be a fully-qualified URL that is the destination of the redirect.
     */
    function hook_exit($destination = NULL) {
      db_update('counter')
        ->expression('hits', 'hits + 1')
        ->condition('type', 1)
        ->execute();
    }
    
    /**
     * Perform necessary alterations to the JavaScript before it is presented on
     * the page.
     *
     * @param $javascript
     *   An array of all JavaScript being presented on the page.
     *
     * @see drupal_add_js()
     * @see drupal_get_js()
     * @see drupal_js_defaults()
     */
    function hook_js_alter(&$javascript) {
      // Swap out jQuery to use an updated version of the library.
      $javascript['misc/jquery.js']['data'] = drupal_get_path('module', 'jquery_update') . '/jquery.js';
    }
    
    /**
     * Registers JavaScript/CSS libraries associated with a module.
     *
     * Modules implementing this return an array of arrays. The key to each
     * sub-array is the machine readable name of the library. Each library may
     * contain the following items:
     *
     * - 'title': The human readable name of the library.
     * - 'website': The URL of the library's web site.
     * - 'version': A string specifying the version of the library; intentionally
     *   not a float because a version like "1.2.3" is not a valid float. Use PHP's
     *   version_compare() to compare different versions.
     * - 'js': An array of JavaScript elements; each element's key is used as $data
     *   argument, each element's value is used as $options array for
     *   drupal_add_js(). To add library-specific (not module-specific) JavaScript
     *   settings, the key may be skipped, the value must specify
     *   'type' => 'setting', and the actual settings must be contained in a 'data'
     *   element of the value.
     * - 'css': Like 'js', an array of CSS elements passed to drupal_add_css().
     * - 'dependencies': An array of libraries that are required for a library. Each
     *   element is an array listing the module and name of another library. Note
     *   that all dependencies for each dependent library will also be added when
     *   this library is added.
     *
     * Registered information for a library should contain re-usable data only.
     * Module- or implementation-specific data and integration logic should be added
     * separately.
     *
     * @return
     *   An array defining libraries associated with a module.
     *
     * @see system_library()
     * @see drupal_add_library()
     * @see drupal_get_library()
     */
    function hook_library() {
      // Library One.
      $libraries['library-1'] = array(
        'title' => 'Library One',
        'website' => 'http://example.com/library-1',
        'version' => '1.2',
        'js' => array(
          drupal_get_path('module', 'my_module') . '/library-1.js' => array(),
        ),
        'css' => array(
          drupal_get_path('module', 'my_module') . '/library-2.css' => array(
            'type' => 'file',
            'media' => 'screen',
          ),
        ),
      );
      // Library Two.
      $libraries['library-2'] = array(
        'title' => 'Library Two',
        'website' => 'http://example.com/library-2',
        'version' => '3.1-beta1',
        'js' => array(
          // JavaScript settings may use the 'data' key.
          array(
            'type' => 'setting',
            'data' => array('library2' => TRUE),
          ),
        ),
        'dependencies' => array(
          // Require jQuery UI core by System module.
          array('system', 'ui'),
          // Require our other library.
          array('my_module', 'library-1'),
          // Require another library.
          array('other_module', 'library-3'),
        ),
      );
      return $libraries;
    }
    
    /**
     * Alters the JavaScript/CSS library registry.
     *
     * Allows certain, contributed modules to update libraries to newer versions
     * while ensuring backwards compatibility. In general, such manipulations should
     * only be done by designated modules, since most modules that integrate with a
     * certain library also depend on the API of a certain library version.
     *
     * @param $libraries
     *   The JavaScript/CSS libraries provided by $module. Keyed by internal library
     *   name and passed by reference.
     * @param $module
     *   The name of the module that registered the libraries.
     *
     * @see hook_library()
     */
    function hook_library_alter(&$libraries, $module) {
      // Update Farbtastic to version 2.0.
      if ($module == 'system' && isset($libraries['farbtastic'])) {
        // Verify existing version is older than the one we are updating to.
        if (version_compare($libraries['farbtastic']['version'], '2.0', '<')) {
          // Update the existing Farbtastic to version 2.0.
          $libraries['farbtastic']['version'] = '2.0';
          $libraries['farbtastic']['js'] = array(
            drupal_get_path('module', 'farbtastic_update') . '/farbtastic-2.0.js' => array(),
          );
        }
      }
    }
    
    /**
     * Alter CSS files before they are output on the page.
     *
     * @param $css
     *   An array of all CSS items (files and inline CSS) being requested on the page.
     *
     * @see drupal_add_css()
     * @see drupal_get_css()
     */
    function hook_css_alter(&$css) {
      // Remove defaults.css file.
      unset($css[drupal_get_path('module', 'system') . '/defaults.css']);
    }
    
    /**
     * Alter the commands that are sent to the user through the Ajax framework.
     *
     * @param $commands
     *   An array of all commands that will be sent to the user.
     *
     * @see ajax_render()
     */
    function hook_ajax_render_alter($commands) {
      // Inject any new status messages into the content area.
      $commands[] = ajax_command_prepend('#block-system-main .content', theme('status_messages'));
    }
    
    /**
     * Add elements to a page before it is rendered.
     *
     * Use this hook when you want to add elements at the page level. For your
     * additions to be printed, they have to be placed below a top level array key
     * of the $page array that has the name of a region of the active theme.
     *
     * By default, valid region keys are 'page_top', 'header', 'sidebar_first',
     * 'content', 'sidebar_second' and 'page_bottom'. To get a list of all regions
     * of the active theme, use system_region_list($theme). Note that $theme is a
     * global variable.
     *
     * If you want to alter the elements added by other modules or if your module
     * depends on the elements of other modules, use hook_page_alter() instead which
     * runs after this hook.
     *
     * @param $page
     *   Nested array of renderable elements that make up the page.
     *
     * @see hook_page_alter()
     * @see drupal_render_page()
     */
    function hook_page_build(&$page) {
      if (menu_get_object('node', 1)) {
        // We are on a node detail page. Append a standard disclaimer to the
        // content region.
        $page['content']['disclaimer'] = array(
          '#markup' => t('Acme, Inc. is not responsible for the contents of this sample code.'),
          '#weight' => 25,
        );
      }
    }
    
    /**
     * Alter a menu router item right after it has been retrieved from the database or cache.
     *
     * This hook is invoked by menu_get_item() and allows for run-time alteration of router
     * information (page_callback, title, and so on) before it is translated and checked for
     * access. The passed in $router_item is statically cached for the current request, so this
     * hook is only invoked once for any router item that is retrieved via menu_get_item().
     *
     * Usually, modules will only want to inspect the router item and conditionally
     * perform other actions (such as preparing a state for the current request).
     * Note that this hook is invoked for any router item that is retrieved by
     * menu_get_item(), which may or may not be called on the path itself, so implementations
     * should check the $path parameter if the alteration should fire for the current request
     * only.
     *
     * @param $router_item
     *   The menu router item for $path.
     * @param $path
     *   The originally passed path, for which $router_item is responsible.
     * @param $original_map
     *   The path argument map, as contained in $path.
     *
     * @see menu_get_item()
     */
    function hook_menu_get_item_alter(&$router_item, $path, $original_map) {
      // When retrieving the router item for the current path...
      if ($path == $_GET['q']) {
        // ...call a function that prepares something for this request.
        mymodule_prepare_something();
      }
    }
    
    /**
     * Define menu items and page callbacks.
     *
     * This hook enables modules to register paths in order to define how URL
     * requests are handled. Paths may be registered for URL handling only, or they
     * can register a link to be placed in a menu (usually the Navigation menu). A
     * path and its associated information is commonly called a "menu router item".
     * This hook is rarely called (for example, when modules are enabled), and
     * its results are cached in the database.
     *
     * hook_menu() implementations return an associative array whose keys define
     * paths and whose values are an associative array of properties for each
     * path. (The complete list of properties is in the return value section below.)
     *
     * The definition for each path may include a page callback function, which is
     * invoked when the registered path is requested. If there is no other
     * registered path that fits the requested path better, any further path
     * components are passed to the callback function. For example, your module
     * could register path 'abc/def':
     * @code
     *   function mymodule_menu() {
     *     $items['abc/def'] = array(
     *       'page callback' => 'mymodule_abc_view',
     *     );
     *     return $items;
     *   }
     *
     *   function mymodule_abc_view($ghi = 0, $jkl = '') {
     *     // ...
     *   }
     * @endcode
     * When path 'abc/def' is requested, no further path components are in the
     * request, and no additional arguments are passed to the callback function (so
     * $ghi and $jkl would take the default values as defined in the function
     * signature). When 'abc/def/123/foo' is requested, $ghi will be '123' and
     * $jkl will be 'foo'. Note that this automatic passing of optional path
     * arguments applies only to page and theme callback functions.
     *
     * In addition to optional path arguments, the page callback and other callback
     * functions may specify argument lists as arrays. These argument lists may
     * contain both fixed/hard-coded argument values and integers that correspond
     * to path components. When integers are used and the callback function is
     * called, the corresponding path components will be substituted for the
     * integers. That is, the integer 0 in an argument list will be replaced with
     * the first path component, integer 1 with the second, and so on (path
     * components are numbered starting from zero). This substitution feature allows
     * you to re-use a callback function for several different paths. For example:
     * @code
     *   function mymodule_menu() {
     *     $items['abc/def'] = array(
     *       'page callback' => 'mymodule_abc_view',
     *       'page arguments' => array(1, 'foo'),
     *     );
     *     return $items;
     *   }
     * @endcode
     * When path 'abc/def' is requested, the page callback function will get 'def'
     * as the first argument and (always) 'foo' as the second argument.
     *
     * Note that if a page or theme callback function has an argument list array,
     * these arguments will be passed first to the function, followed by any
     * any arguments generated by optional path arguments as described above.
     *
     * Special care should be taken for the page callback drupal_get_form(), because
     * your specific form callback function will always receive $form and
     * &$form_state as the first function arguments:
     * @code
     *   function mymodule_abc_form($form, &$form_state) {
     *     // ...
     *     return $form;
     *   }
     * @endcode
     * See @link form_api Form API documentation @endlink for details.
     *
     * Wildcards within paths also work with integer substitution. For example,
     * your module could register path 'my-module/%/edit':
     * @code
     *   $items['my-module/%/edit'] = array(
     *     'page callback' => 'mymodule_abc_edit',
     *     'page arguments' => array(1),
     *   );
     * @endcode
     * When path 'my-module/foo/edit' is requested, integer 1 will be replaced
     * with 'foo' and passed to the callback function.
     *
     * Registered paths may also contain special "auto-loader" wildcard components
     * in the form of '%mymodule_abc', where the '%' part means that this path
     * component is a wildcard, and the 'mymodule_abc' part defines the prefix for a
     * load function, which here would be named mymodule_abc_load(). When a matching
     * path is requested, your load function will receive as its first argument the
     * path component in the position of the wildcard; load functions may also be
     * passed additional arguments (see "load arguments" in the return value
     * section below). For example, your module could register path
     * 'my-module/%mymodule_abc/edit':
     * @code
     *   $items['my-module/%mymodule_abc/edit'] = array(
     *     'page callback' => 'mymodule_abc_edit',
     *     'page arguments' => array(1),
     *   );
     * @endcode
     * When path 'my-module/123/edit' is requested, your load function
     * mymodule_abc_load() will be invoked with the argument '123', and should
     * load and return an "abc" object with internal id 123:
     * @code
     *   function mymodule_abc_load($abc_id) {
     *     return db_query("SELECT * FROM {mymodule_abc} WHERE abc_id = :abc_id", array(':abc_id' => $abc_id))->fetchObject();
     *   }
     * @endcode
     * This 'abc' object will then be passed into the page callback function
     * mymodule_abc_edit() to replace the integer 1 in the page arguments.
     *
     * You can also make groups of menu items to be rendered (by default) as tabs
     * on a page. To do that, first create one menu item of type MENU_NORMAL_ITEM,
     * with your chosen path, such as 'foo'. Then duplicate that menu item, using a
     * subdirectory path, such as 'foo/tab1', and changing the type to
     * MENU_DEFAULT_LOCAL_TASK to make it the default tab for the group. Then add
     * the additional tab items, with paths such as "foo/tab2" etc., with type
     * MENU_LOCAL_TASK. Example:
     * @code
     * // Make "Foo settings" appear on the admin Config page
     * $items['admin/config/foo'] = array(
     *   'title' => 'Foo settings',
     *   'type' => MENU_NORMAL_ITEM,
     *   // Page callback, etc. need to be added here.
     * );
     * // Make "Global settings" the main tab on the "Foo settings" page
     * $items['admin/config/foo/global'] = array(
     *   'title' => 'Global settings',
     *   'type' => MENU_DEFAULT_LOCAL_TASK,
     *   // Access callback, page callback, and theme callback will be inherited
     *   // from 'admin/config/foo', if not specified here to override.
     * );
     * // Make an additional tab called "Node settings" on "Foo settings"
     * $items['admin/config/foo/node'] = array(
     *   'title' => 'Node settings',
     *   'type' => MENU_LOCAL_TASK,
     *   // Page callback and theme callback will be inherited from
     *   // 'admin/config/foo', if not specified here to override.
     *   // Need to add access callback or access arguments.
     * );
     * @endcode
     *
     * @return
     *   An array of menu items. Each menu item has a key corresponding to the
     *   Drupal path being registered. The corresponding array value is an
     *   associative array that may contain the following key-value pairs:
     *   - "title": Required. The untranslated title of the menu item.
     *   - "title callback": Function to generate the title; defaults to t().
     *     If you require only the raw string to be output, set this to FALSE.
     *   - "title arguments": Arguments to send to t() or your custom callback,
     *     with path component substitution as described above.
     *   - "description": The untranslated description of the menu item.
     *   - "page callback": The function to call to display a web page when the user
     *     visits the path. If omitted, the parent menu item's callback will be used
     *     instead.
     *   - "page arguments": An array of arguments to pass to the page callback
     *     function, with path component substitution as described above.
     *   - "delivery callback": The function to call to package the result of the
     *     page callback function and send it to the browser. Defaults to
     *     drupal_deliver_html_page() unless a value is inherited from a parent menu
     *     item. Note that this function is called even if the access checks fail,
     *     so any custom delivery callback function should take that into account.
     *     See drupal_deliver_html_page() for an example.
     *   - "access callback": A function returning TRUE if the user has access
     *     rights to this menu item, and FALSE if not. It can also be a boolean
     *     constant instead of a function, and you can also use numeric values
     *     (will be cast to boolean). Defaults to user_access() unless a value is
     *     inherited from the parent menu item; only MENU_DEFAULT_LOCAL_TASK items
     *     can inherit access callbacks. To use the user_access() default callback,
     *     you must specify the permission to check as 'access arguments' (see
     *     below).
     *   - "access arguments": An array of arguments to pass to the access callback
     *     function, with path component substitution as described above. If the
     *     access callback is inherited (see above), the access arguments will be
     *     inherited with it, unless overridden in the child menu item.
     *   - "theme callback": (optional) A function returning the machine-readable
     *     name of the theme that will be used to render the page. If not provided,
     *     the value will be inherited from a parent menu item. If there is no
     *     theme callback, or if the function does not return the name of a current
     *     active theme on the site, the theme for this page will be determined by
     *     either hook_custom_theme() or the default theme instead. As a general
     *     rule, the use of theme callback functions should be limited to pages
     *     whose functionality is very closely tied to a particular theme, since
     *     they can only be overridden by modules which specifically target those
     *     pages in hook_menu_alter(). Modules implementing more generic theme
     *     switching functionality (for example, a module which allows the theme to
     *     be set dynamically based on the current user's role) should use
     *     hook_custom_theme() instead.
     *   - "theme arguments": An array of arguments to pass to the theme callback
     *     function, with path component substitution as described above.
     *   - "file": A file that will be included before the page callback is called;
     *     this allows page callback functions to be in separate files. The file
     *     should be relative to the implementing module's directory unless
     *     otherwise specified by the "file path" option. Does not apply to other
     *     callbacks (only page callback).
     *   - "file path": The path to the directory containing the file specified in
     *     "file". This defaults to the path to the module implementing the hook.
     *   - "load arguments": An array of arguments to be passed to each of the
     *     wildcard object loaders in the path, after the path argument itself.
     *     For example, if a module registers path node/%node/revisions/%/view
     *     with load arguments set to array(3), the '%node' in the path indicates
     *     that the loader function node_load() will be called with the second
     *     path component as the first argument. The 3 in the load arguments
     *     indicates that the fourth path component will also be passed to
     *     node_load() (numbering of path components starts at zero). So, if path
     *     node/12/revisions/29/view is requested, node_load(12, 29) will be called.
     *     There are also two "magic" values that can be used in load arguments.
     *     "%index" indicates the index of the wildcard path component. "%map"
     *     indicates the path components as an array. For example, if a module
     *     registers for several paths of the form 'user/%user_category/edit/*', all
     *     of them can use the same load function user_category_load(), by setting
     *     the load arguments to array('%map', '%index'). For instance, if the user
     *     is editing category 'foo' by requesting path 'user/32/edit/foo', the load
     *     function user_category_load() will be called with 32 as its first
     *     argument, the array ('user', 32, 'edit', 'foo') as the map argument,
     *     and 1 as the index argument (because %user_category is the second path
     *     component and numbering starts at zero). user_category_load() can then
     *     use these values to extract the information that 'foo' is the category
     *     being requested.
     *   - "weight": An integer that determines the relative position of items in
     *     the menu; higher-weighted items sink. Defaults to 0. Menu items with the
     *     same weight are ordered alphabetically.
     *   - "menu_name": Optional. Set this to a custom menu if you don't want your
     *     item to be placed in Navigation.
     *   - "context": (optional) Defines the context a tab may appear in. By
     *     default, all tabs are only displayed as local tasks when being rendered
     *     in a page context. All tabs that should be accessible as contextual links
     *     in page region containers outside of the parent menu item's primary page
     *     context should be registered using one of the following contexts:
     *     - MENU_CONTEXT_PAGE: (default) The tab is displayed as local task for the
     *       page context only.
     *     - MENU_CONTEXT_INLINE: The tab is displayed as contextual link outside of
     *       the primary page context only.
     *     Contexts can be combined. For example, to display a tab both on a page
     *     and inline, a menu router item may specify:
     *     @code
     *       'context' => MENU_CONTEXT_PAGE | MENU_CONTEXT_INLINE,
     *     @endcode
     *   - "tab_parent": For local task menu items, the path of the task's parent
     *     item; defaults to the same path without the last component (e.g., the
     *     default parent for 'admin/people/create' is 'admin/people').
     *   - "tab_root": For local task menu items, the path of the closest non-tab
     *     item; same default as "tab_parent".
     *   - "position": Position of the block ('left' or 'right') on the system
     *     administration page for this item.
     *   - "type": A bitmask of flags describing properties of the menu item.
     *     Many shortcut bitmasks are provided as constants in menu.inc:
     *     - MENU_NORMAL_ITEM: Normal menu items show up in the menu tree and can be
     *       moved/hidden by the administrator.
     *     - MENU_CALLBACK: Callbacks simply register a path so that the correct
     *       information is generated when the path is accessed.
     *     - MENU_SUGGESTED_ITEM: Modules may "suggest" menu items that the
     *       administrator may enable.
     *     - MENU_LOCAL_ACTION: Local actions are menu items that describe actions
     *       on the parent item such as adding a new user or block, and are
     *       rendered in the action-links list in your theme.
     *     - MENU_LOCAL_TASK: Local tasks are menu items that describe different
     *       displays of data, and are generally rendered as tabs.
     *     - MENU_DEFAULT_LOCAL_TASK: Every set of local tasks should provide one
     *       "default" task, which should display the same page as the parent item.
     *     If the "type" element is omitted, MENU_NORMAL_ITEM is assumed.
     *   - "options": An array of options to be passed to l() when generating a link
     *     from this menu item.
     *
     * For a detailed usage example, see page_example.module.
     * For comprehensive documentation on the menu system, see
     * http://drupal.org/node/102338.
     */
    function hook_menu() {
      $items['blog'] = array(
        'title' => 'blogs',
        'page callback' => 'blog_page',
        'access arguments' => array('access content'),
        'type' => MENU_SUGGESTED_ITEM,
      );
      $items['blog/feed'] = array(
        'title' => 'RSS feed',
        'page callback' => 'blog_feed',
        'access arguments' => array('access content'),
        'type' => MENU_CALLBACK,
      );
    
      return $items;
    }
    
    /**
     * Alter the data being saved to the {menu_router} table after hook_menu is invoked.
     *
     * This hook is invoked by menu_router_build(). The menu definitions are passed
     * in by reference. Each element of the $items array is one item returned
     * by a module from hook_menu. Additional items may be added, or existing items
     * altered.
     *
     * @param $items
     *   Associative array of menu router definitions returned from hook_menu().
     */
    function hook_menu_alter(&$items) {
      // Example - disable the page at node/add
      $items['node/add']['access callback'] = FALSE;
    }
    
    /**
     * Alter the data being saved to the {menu_links} table by menu_link_save().
     *
     * @param $item
     *   Associative array defining a menu link as passed into menu_link_save().
     *
     * @see hook_translated_menu_link_alter()
     */
    function hook_menu_link_alter(&$item) {
      // Make all new admin links hidden (a.k.a disabled).
      if (strpos($item['link_path'], 'admin') === 0 && empty($item['mlid'])) {
        $item['hidden'] = 1;
      }
      // Flag a link to be altered by hook_translated_menu_link_alter().
      if ($item['link_path'] == 'devel/cache/clear') {
        $item['options']['alter'] = TRUE;
      }
      // Flag a link to be altered by hook_translated_menu_link_alter(), but only
      // if it is derived from a menu router item; i.e., do not alter a custom
      // menu link pointing to the same path that has been created by a user.
      if ($item['link_path'] == 'user' && $item['module'] == 'system') {
        $item['options']['alter'] = TRUE;
      }
    }
    
    /**
     * Alter a menu link after it has been translated and before it is rendered.
     *
     * This hook is invoked from _menu_link_translate() after a menu link has been
     * translated; i.e., after dynamic path argument placeholders (%) have been
     * replaced with actual values, the user access to the link's target page has
     * been checked, and the link has been localized. It is only invoked if
     * $item['options']['alter'] has been set to a non-empty value (e.g., TRUE).
     * This flag should be set using hook_menu_link_alter().
     *
     * Implementations of this hook are able to alter any property of the menu link.
     * For example, this hook may be used to add a page-specific query string to all
     * menu links, or hide a certain link by setting:
     * @code
     *   'hidden' => 1,
     * @endcode
     *
     * @param $item
     *   Associative array defining a menu link after _menu_link_translate()
     * @param $map
     *   Associative array containing the menu $map (path parts and/or objects).
     *
     * @see hook_menu_link_alter()
     */
    function hook_translated_menu_link_alter(&$item, $map) {
      if ($item['href'] == 'devel/cache/clear') {
        $item['localized_options']['query'] = drupal_get_destination();
      }
    }
    
    /**
     * Inform modules that a menu link has been created.
     *
     * This hook is used to notify modules that menu items have been
     * created. Contributed modules may use the information to perform
     * actions based on the information entered into the menu system.
     *
     * @param $link
     *   Associative array defining a menu link as passed into menu_link_save().
     *
     * @see hook_menu_link_update()
     * @see hook_menu_link_delete()
     */
    function hook_menu_link_insert($link) {
      // In our sample case, we track menu items as editing sections
      // of the site. These are stored in our table as 'disabled' items.
      $record['mlid'] = $link['mlid'];
      $record['menu_name'] = $link['menu_name'];
      $record['status'] = 0;
      drupal_write_record('menu_example', $record);
    }
    
    /**
     * Inform modules that a menu link has been updated.
     *
     * This hook is used to notify modules that menu items have been
     * updated. Contributed modules may use the information to perform
     * actions based on the information entered into the menu system.
     *
     * @param $link
     *   Associative array defining a menu link as passed into menu_link_save().
     *
     * @see hook_menu_link_insert()
     * @see hook_menu_link_delete()
     */
    function hook_menu_link_update($link) {
      // If the parent menu has changed, update our record.
      $menu_name = db_result(db_query("SELECT mlid, menu_name, status FROM {menu_example} WHERE mlid = :mlid", array(':mlid' => $link['mlid'])));
      if ($menu_name != $link['menu_name']) {
        db_update('menu_example')
          ->fields(array('menu_name' => $link['menu_name']))
          ->condition('mlid', $link['mlid'])
          ->execute();
      }
    }
    
    /**
     * Inform modules that a menu link has been deleted.
     *
     * This hook is used to notify modules that menu items have been
     * deleted. Contributed modules may use the information to perform
     * actions based on the information entered into the menu system.
     *
     * @param $link
     *   Associative array defining a menu link as passed into menu_link_save().
     *
     * @see hook_menu_link_insert()
     * @see hook_menu_link_update()
     */
    function hook_menu_link_delete($link) {
      // Delete the record from our table.
      db_delete('menu_example')
        ->condition('mlid', $link['mlid'])
        ->execute();
    }
    
    /**
     * Alter tabs and actions displayed on the page before they are rendered.
     *
     * This hook is invoked by menu_local_tasks(). The system-determined tabs and
     * actions are passed in by reference. Additional tabs or actions may be added,
     * or existing items altered.
     *
     * Each tab or action is an associative array containing:
     * - #theme: The theme function to use to render.
     * - #link: An associative array containing:
     *   - title: The localized title of the link.
     *   - href: The system path to link to.
     *   - localized_options: An array of options to pass to url().
     * - #active: Whether the link should be marked as 'active'.
     *
     * @param $data
     *   An associative array containing:
     *   - actions: An associative array containing:
     *     - count: The amount of actions determined by the menu system, which can
     *       be ignored.
     *     - output: A list of of actions, each one being an associative array
     *       as described above.
     *   - tabs: An indexed array (list) of tab levels (up to 2 levels), each
     *     containing an associative array:
     *     - count: The amount of tabs determined by the menu system. This value
     *       does not need to be altered if there is more than one tab.
     *     - output: A list of of tabs, each one being an associative array as
     *       described above.
     * @param $router_item
     *   The menu system router item of the page.
     * @param $root_path
     *   The path to the root item for this set of tabs.
     */
    function hook_menu_local_tasks_alter(&$data, $router_item, $root_path) {
      // Add an action linking to node/add to all pages.
      $data['actions']['output'][] = array(
        '#theme' => 'menu_local_task',
        '#link' => array(
          'title' => t('Add new content'),
          'href' => 'node/add',
          'localized_options' => array(
            'attributes' => array(
              'title' => t('Add new content'),
            ),
          ),
        ),
      );
    
      // Add a tab linking to node/add to all pages.
      $data['tabs'][0]['output'][] = array(
        '#theme' => 'menu_local_task',
        '#link' => array(
          'title' => t('Example tab'),
          'href' => 'node/add',
          'localized_options' => array(
            'attributes' => array(
              'title' => t('Add new content'),
            ),
          ),
        ),
        // Define whether this link is active. This can be omitted for
        // implementations that add links to pages outside of the current page
        // context.
        '#active' => ($router_item['path'] == $root_path),
      );
    }
    
    /**
     * Alter links in the active trail before it is rendered as the breadcrumb.
     *
     * This hook is invoked by menu_get_active_breadcrumb() and allows alteration
     * of the breadcrumb links for the current page, which may be preferred instead
     * of setting a custom breadcrumb via drupal_set_breadcrumb().
     *
     * Implementations should take into account that menu_get_active_breadcrumb()
     * subsequently performs the following adjustments to the active trail *after*
     * this hook has been invoked:
     * - The last link in $active_trail is removed, if its 'href' is identical to
     *   the 'href' of $item. This happens, because the breadcrumb normally does
     *   not contain a link to the current page.
     * - The (second to) last link in $active_trail is removed, if the current $item
     *   is a MENU_DEFAULT_LOCAL_TASK. This happens in order to do not show a link
     *   to the current page, when being on the path for the default local task;
     *   e.g. when being on the path node/%/view, the breadcrumb should not contain
     *   a link to node/%.
     *
     * Each link in the active trail must contain:
     * - title: The localized title of the link.
     * - href: The system path to link to.
     * - localized_options: An array of options to pass to url().
     *
     * @param $active_trail
     *   An array containing breadcrumb links for the current page.
     * @param $item
     *   The menu router item of the current page.
     *
     * @see drupal_set_breadcrumb()
     * @see menu_get_active_breadcrumb()
     * @see menu_get_active_trail()
     * @see menu_set_active_trail()
     */
    function hook_menu_breadcrumb_alter(&$active_trail, $item) {
      // Always display a link to the current page by duplicating the last link in
      // the active trail. This means that menu_get_active_breadcrumb() will remove
      // the last link (for the current page), but since it is added once more here,
      // it will appear.
      if (!drupal_is_front_page()) {
        $end = end($active_trail);
        if ($item['href'] == $end['href']) {
          $active_trail[] = $end;
        }
      }
    }
    
    /**
     * Alter contextual links before they are rendered.
     *
     * This hook is invoked by menu_contextual_links(). The system-determined
     * contextual links are passed in by reference. Additional links may be added
     * or existing links can be altered.
     *
     * Each contextual link must at least contain:
     * - title: The localized title of the link.
     * - href: The system path to link to.
     * - localized_options: An array of options to pass to url().
     *
     * @param $links
     *   An associative array containing contextual links for the given $root_path,
     *   as described above. The array keys are used to build CSS class names for
     *   contextual links and must therefore be unique for each set of contextual
     *   links.
     * @param $router_item
     *   The menu router item belonging to the $root_path being requested.
     * @param $root_path
     *   The (parent) path that has been requested to build contextual links for.
     *   This is a normalized path, which means that an originally passed path of
     *   'node/123' became 'node/%'.
     *
     * @see hook_contextual_links_view_alter()
     * @see menu_contextual_links()
     * @see hook_menu()
     * @see contextual_preprocess()
     */
    function hook_menu_contextual_links_alter(&$links, $router_item, $root_path) {
      // Add a link to all contextual links for nodes.
      if ($root_path == 'node/%') {
        $links['foo'] = array(
          'title' => t('Do fu'),
          'href' => 'foo/do',
          'localized_options' => array(
            'query' => array(
              'foo' => 'bar',
            ),
          ),
        );
      }
    }
    
    /**
     * Perform alterations before a page is rendered.
     *
     * Use this hook when you want to remove or alter elements at the page
     * level, or add elements at the page level that depend on an other module's
     * elements (this hook runs after hook_page_build().
     *
     * If you are making changes to entities such as forms, menus, or user
     * profiles, use those objects' native alter hooks instead (hook_form_alter(),
     * for example).
     *
     * The $page array contains top level elements for each block region:
     * @code
     *   $page['page_top']
     *   $page['header']
     *   $page['sidebar_first']
     *   $page['content']
     *   $page['sidebar_second']
     *   $page['page_bottom']
     * @endcode
     *
     * The 'content' element contains the main content of the current page, and its
     * structure will vary depending on what module is responsible for building the
     * page. Some legacy modules may not return structured content at all: their
     * pre-rendered markup will be located in $page['content']['main']['#markup'].
     *
     * Pages built by Drupal's core Node and Blog modules use a standard structure:
     *
     * @code
     *   // Node body.
     *   $page['content']['system_main']['nodes'][$nid]['body']
     *   // Array of links attached to the node (add comments, read more).
     *   $page['content']['system_main']['nodes'][$nid]['links']
     *   // The node object itself.
     *   $page['content']['system_main']['nodes'][$nid]['#node']
     *   // The results pager.
     *   $page['content']['system_main']['pager']
     * @endcode
     *
     * Blocks may be referenced by their module/delta pair within a region:
     * @code
     *   // The login block in the first sidebar region.
     *   $page['sidebar_first']['user_login']['#block'];
     * @endcode
     *
     * @param $page
     *   Nested array of renderable elements that make up the page.
     *
     * @see hook_page_build()
     * @see drupal_render_page()
     */
    function hook_page_alter(&$page) {
      // Add help text to the user login block.
      $page['sidebar_first']['user_login']['help'] = array(
        '#weight' => -10,
        '#markup' => t('To post comments or add new content, you first have to log in.'),
      );
    }
    
    /**
     * Perform alterations before a form is rendered.
     *
     * One popular use of this hook is to add form elements to the node form. When
     * altering a node form, the node object can be accessed at $form['#node'].
     *
     * Note that instead of hook_form_alter(), which is called for all forms, you
     * can also use hook_form_FORM_ID_alter() to alter a specific form. For each
     * module (in system weight order) the general form alter hook implementation
     * is invoked first, then the form ID specific alter implementation is called.
     * After all module hook implementations are invoked, the hook_form_alter()
     * implementations from themes are invoked in the same manner.
     *
     * @param $form
     *   Nested array of form elements that comprise the form.
     * @param $form_state
     *   A keyed array containing the current state of the form. The arguments
     *   that drupal_get_form() was originally called with are available in the
     *   array $form_state['build_info']['args'].
     * @param $form_id
     *   String representing the name of the form itself. Typically this is the
     *   name of the function that generated the form.
     *
     * @see hook_form_FORM_ID_alter()
     */
    function hook_form_alter(&$form, &$form_state, $form_id) {
      if (isset($form['type']) && $form['type']['#value'] . '_node_settings' == $form_id) {
        $form['workflow']['upload_' . $form['type']['#value']] = array(
          '#type' => 'radios',
          '#title' => t('Attachments'),
          '#default_value' => variable_get('upload_' . $form['type']['#value'], 1),
          '#options' => array(t('Disabled'), t('Enabled')),
        );
      }
    }
    
    /**
     * Provide a form-specific alteration instead of the global hook_form_alter().
     *
     * Modules can implement hook_form_FORM_ID_alter() to modify a specific form,
     * rather than implementing hook_form_alter() and checking the form ID, or
     * using long switch statements to alter multiple forms.
     *
     * @param $form
     *   Nested array of form elements that comprise the form.
     * @param $form_state
     *   A keyed array containing the current state of the form. The arguments
     *   that drupal_get_form() was originally called with are available in the
     *   array $form_state['build_info']['args'].
     * @param $form_id
     *   String representing the name of the form itself. Typically this is the
     *   name of the function that generated the form.
     *
     * @see hook_form_alter()
     * @see drupal_prepare_form()
     */
    function hook_form_FORM_ID_alter(&$form, &$form_state, $form_id) {
      // Modification for the form with the given form ID goes here. For example, if
      // FORM_ID is "user_register_form" this code would run only on the user
      // registration form.
    
      // Add a checkbox to registration form about agreeing to terms of use.
      $form['terms_of_use'] = array(
        '#type' => 'checkbox',
        '#title' => t("I agree with the website's terms and conditions."),
        '#required' => TRUE,
      );
    }
    
    /**
     * Provide a form-specific alteration for shared forms.
     *
     * Modules can implement hook_form_BASE_FORM_ID_alter() to modify a specific
     * form belonging to multiple form_ids, rather than implementing
     * hook_form_alter() and checking for conditions that would identify the
     * shared form constructor.
     *
     * Examples for such forms are node_form() or comment_form().
     *
     * Note that this hook fires after hook_form_FORM_ID_alter() and before
     * hook_form_alter().
     *
     * @param $form
     *   Nested array of form elements that comprise the form.
     * @param $form_state
     *   A keyed array containing the current state of the form.
     * @param $form_id
     *   String representing the name of the form itself. Typically this is the
     *   name of the function that generated the form.
     *
     * @see hook_form_FORM_ID_alter()
     * @see drupal_prepare_form()
     */
    function hook_form_BASE_FORM_ID_alter(&$form, &$form_state, $form_id) {
      // Modification for the form with the given BASE_FORM_ID goes here. For
      // example, if BASE_FORM_ID is "node_form", this code would run on every
      // node form, regardless of node type.
    
      // Add a checkbox to the node form about agreeing to terms of use.
      $form['terms_of_use'] = array(
        '#type' => 'checkbox',
        '#title' => t("I agree with the website's terms and conditions."),
        '#required' => TRUE,
      );
    }
    
    /**
     * Map form_ids to form builder functions.
     *
     * By default, when drupal_get_form() is called, the system will look for a
     * function with the same name as the form ID, and use that function to build
     * the form. This hook allows you to override that behavior in two ways.
     *
     * First, you can use this hook to tell the form system to use a different
     * function to build certain forms in your module; this is often used to define
     * a form "factory" function that is used to build several similar forms. In
     * this case, your hook implementation will likely ignore all of the input
     * arguments. See node_forms() for an example of this.
     *
     * Second, you could use this hook to define how to build a form with a
     * dynamically-generated form ID. In this case, you would need to verify that
     * the $form_id input matched your module's format for dynamically-generated
     * form IDs, and if so, act appropriately.
     *
     * @param $form_id
     *   The unique string identifying the desired form.
     * @param $args
     *   An array containing the original arguments provided to drupal_get_form()
     *   or drupal_form_submit(). These are always passed to the form builder and
     *   do not have to be specified manually in 'callback arguments'.
     *
     * @return
     *   An associative array whose keys define form_ids and whose values are an
     *   associative array defining the following keys:
     *   - callback: The name of the form builder function to invoke.
     *   - callback arguments: (optional) Additional arguments to pass to the
     *     function defined in 'callback', which are prepended to $args.
     *   - wrapper_callback: (optional) The name of a form builder function to
     *     invoke before the form builder defined in 'callback' is invoked. This
     *     wrapper callback may prepopulate the $form array with form elements,
     *     which will then be already contained in the $form that is passed on to
     *     the form builder defined in 'callback'. For example, a wrapper callback
     *     could setup wizard-alike form buttons that are the same for a variety of
     *     forms that belong to the wizard, which all share the same wrapper
     *     callback.
     */
    function hook_forms($form_id, $args) {
      // Simply reroute the (non-existing) $form_id 'mymodule_first_form' to
      // 'mymodule_main_form'.
      $forms['mymodule_first_form'] = array(
        'callback' => 'mymodule_main_form',
      );
    
      // Reroute the $form_id and prepend an additional argument that gets passed to
      // the 'mymodule_main_form' form builder function.
      $forms['mymodule_second_form'] = array(
        'callback' => 'mymodule_main_form',
        'callback arguments' => array('some parameter'),
      );
    
      // Reroute the $form_id, but invoke the form builder function
      // 'mymodule_main_form_wrapper' first, so we can prepopulate the $form array
      // that is passed to the actual form builder 'mymodule_main_form'.
      $forms['mymodule_wrapped_form'] = array(
        'callback' => 'mymodule_main_form',
        'wrapper_callback' => 'mymodule_main_form_wrapper',
      );
    
      return $forms;
    }
    
    /**
     * Perform setup tasks. See also, hook_init.
     *
     * This hook is run at the beginning of the page request. It is typically
     * used to set up global parameters which are needed later in the request.
     *
     * Only use this hook if your code must run even for cached page views.This hook
     * is called before modules or most include files are loaded into memory.
     * It happens while Drupal is still in bootstrap mode.
     */
    function hook_boot() {
      // we need user_access() in the shutdown function. make sure it gets loaded
      drupal_load('module', 'user');
      drupal_register_shutdown_function('devel_shutdown');
    }
    
    /**
     * Perform setup tasks. See also, hook_boot.
     *
     * This hook is run at the beginning of the page request. It is typically
     * used to set up global parameters which are needed later in the request.
     * when this hook is called, all modules are already loaded in memory.
     *
     * This hook is not run on cached pages.
     *
     * To add CSS or JS that should be present on all pages, modules should not
     * implement this hook, but declare these files in their .info file.
     */
    function hook_init() {
      // Since this file should only be loaded on the front page, it cannot be
      // declared in the info file.
      if (drupal_is_front_page()) {
        drupal_add_css(drupal_get_path('module', 'foo') . '/foo.css');
      }
    }
    
    /**
     * Define image toolkits provided by this module.
     *
     * The file which includes each toolkit's functions must be declared as part of
     * the files array in the module .info file so that the registry will find and
     * parse it.
     *
     * The toolkit's functions must be named image_toolkitname_operation().
     * where the operation may be:
     *   - 'load': Required. See image_gd_load() for usage.
     *   - 'save': Required. See image_gd_save() for usage.
     *   - 'settings': Optional. See image_gd_settings() for usage.
     *   - 'resize': Optional. See image_gd_resize() for usage.
     *   - 'rotate': Optional. See image_gd_rotate() for usage.
     *   - 'crop': Optional. See image_gd_crop() for usage.
     *   - 'desaturate': Optional. See image_gd_desaturate() for usage.
     *
     * @return
     *   An array with the toolkit name as keys and sub-arrays with these keys:
     *     - 'title': A string with the toolkit's title.
     *     - 'available': A Boolean value to indicate that the toolkit is operating
     *       properly, e.g. all required libraries exist.
     *
     * @see system_image_toolkits()
     */
    function hook_image_toolkits() {
      return array(
        'working' => array(
          'title' => t('A toolkit that works.'),
          'available' => TRUE,
        ),
        'broken' => array(
          'title' => t('A toolkit that is "broken" and will not be listed.'),
          'available' => FALSE,
        ),
      );
    }
    
    /**
     * Alter an email message created with the drupal_mail() function.
     *
     * hook_mail_alter() allows modification of email messages created and sent
     * with drupal_mail(). Usage examples include adding and/or changing message
     * text, message fields, and message headers.
     *
     * Email messages sent using functions other than drupal_mail() will not
     * invoke hook_mail_alter(). For example, a contributed module directly
     * calling the drupal_mail_system()->mail() or PHP mail() function
     * will not invoke this hook. All core modules use drupal_mail() for
     * messaging, it is best practice but not mandatory in contributed modules.
     *
     * @param $message
     *   An array containing the message data. Keys in this array include:
     *  - 'id':
     *     The drupal_mail() id of the message. Look at module source code or
     *     drupal_mail() for possible id values.
     *  - 'to':
     *     The address or addresses the message will be sent to. The
     *     formatting of this string must comply with RFC 2822.
     *  - 'from':
     *     The address the message will be marked as being from, which is
     *     either a custom address or the site-wide default email address.
     *  - 'subject':
     *     Subject of the email to be sent. This must not contain any newline
     *     characters, or the email may not be sent properly.
     *  - 'body':
     *     An array of strings containing the message text. The message body is
     *     created by concatenating the individual array strings into a single text
     *     string using "\n\n" as a separator.
     *  - 'headers':
     *     Associative array containing mail headers, such as From, Sender,
     *     MIME-Version, Content-Type, etc.
     *  - 'params':
     *     An array of optional parameters supplied by the caller of drupal_mail()
     *     that is used to build the message before hook_mail_alter() is invoked.
     *  - 'language':
     *     The language object used to build the message before hook_mail_alter()
     *     is invoked.
     *
     * @see drupal_mail()
     */
    function hook_mail_alter(&$message) {
      if ($message['id'] == 'modulename_messagekey') {
        $message['body'][] = "--\nMail sent out from " . variable_get('sitename', t('Drupal'));
      }
    }
    
    /**
     * Alter the registry of modules implementing a hook.
     *
     * This hook is invoked during module_implements(). A module may implement this
     * hook in order to reorder the implementing modules, which are otherwise
     * ordered by the module's system weight.
     *
     * @param &$implementations
     *   An array keyed by the module's name. The value of each item corresponds
     *   to a $group, which is usually FALSE, unless the implementation is in a
     *   file named $module.$group.inc.
     * @param $hook
     *   The name of the module hook being implemented.
     */
    function hook_module_implements_alter(&$implementations, $hook) {
      if ($hook == 'rdf_mapping') {
        // Move my_module_rdf_mapping() to the end of the list. module_implements()
        // iterates through $implementations with a foreach loop which PHP iterates
        // in the order that the items were added, so to move an item to the end of
        // the array, we remove it and then add it.
        $group = $implementations['my_module'];
        unset($implementations['my_module']);
        $implementations['my_module'] = $group;
      }
    }
    
    /**
     * Alter the information parsed from module and theme .info files
     *
     * This hook is invoked in _system_rebuild_module_data() and in
     * _system_rebuild_theme_data(). A module may implement this hook in order to
     * add to or alter the data generated by reading the .info file with
     * drupal_parse_info_file().
     *
     * @param &$info
     *   The .info file contents, passed by reference so that it can be altered.
     * @param $file
     *   Full information about the module or theme, including $file->name, and
     *   $file->filename
     * @param $type
     *   Either 'module' or 'theme', depending on the type of .info file that was
     *   passed.
     */
    function hook_system_info_alter(&$info, $file, $type) {
      // Only fill this in if the .info file does not define a 'datestamp'.
      if (empty($info['datestamp'])) {
        $info['datestamp'] = filemtime($file->filename);
      }
    }
    
    /**
     * Define user permissions.
     *
     * This hook can supply permissions that the module defines, so that they
     * can be selected on the user permissions page and used to grant or restrict
     * access to actions the module performs.
     *
     * Permissions are checked using user_access().
     *
     * For a detailed usage example, see page_example.module.
     *
     * @return
     *   An array whose keys are permission names and whose corresponding values
     *   are arrays containing the following key-value pairs:
     *   - title: The human-readable name of the permission, to be shown on the
     *     permission administration page. This should be wrapped in the t()
     *     function so it can be translated.
     *   - description: (optional) A description of what the permission does. This
     *     should be wrapped in the t() function so it can be translated.
     *   - restrict access: (optional) A boolean which can be set to TRUE to
     *     indicate that site administrators should restrict access to this
     *     permission to trusted users. This should be used for permissions that
     *     have inherent security risks across a variety of potential use cases
     *     (for example, the "administer filters" and "bypass node access"
     *     permissions provided by Drupal core). When set to TRUE, a standard
     *     warning message defined in user_admin_permissions() will be associated
     *     with the permission and displayed with it on the permission
     *     administration page. Defaults to FALSE.
     *   - warning: (optional) A translated warning message to display on the
     *     permission administration page. This warning overrides the automatic
     *     warning generated by 'restrict access' being set to TRUE.
     */
    function hook_permission() {
      return array(
        'administer my module' =>  array(
          'title' => t('Administer my module'),
          'description' => t('Perform administration tasks for my module.'),
        ),
      );
    }
    
    /**
     * Register a module (or theme's) theme implementations.
     *
     * The following parameters are all optional.
     *
     * @param array $existing
     *   An array of existing implementations that may be used for override
     *   purposes. This is primarily useful for themes that may wish to examine
     *   existing implementations to extract data (such as arguments) so that
     *   it may properly register its own, higher priority implementations.
     * @param $type
     *   Whether a theme, module, etc. is being processed. This is primarily useful
     *   so that themes tell if they are the actual theme being called or a parent
     *   theme. May be one of:
     *   - 'module': A module is being checked for theme implementations.
     *   - 'base_theme_engine': A theme engine is being checked for a theme that is
     *     a parent of the actual theme being used.
     *   - 'theme_engine': A theme engine is being checked for the actual theme
     *     being used.
     *   - 'base_theme': A base theme is being checked for theme implementations.
     *   - 'theme': The actual theme in use is being checked.
     * @param $theme
     *   The actual name of theme, module, etc. that is being being processed.
     * @param $path
     *   The directory path of the theme or module, so that it doesn't need to be
     *   looked up.
     *
     * @return array
     *   An associative array of theme hook information. The keys on the outer
     *   array are the internal names of the hooks, and the values are arrays
     *   containing information about the hook. Each array may contain the
     *   following elements:
     *   - variables: (required if "render element" not present) An array of
     *     variables that this theme hook uses. This value allows the theme layer to
     *     properly utilize templates. Each array key represents the name of the
     *     variable and the value will be used as the default value if it is not
     *     given when theme() is called. Template implementations receive these
     *     arguments as variables in the template file. Function implementations
     *     are passed this array data in the $variables parameter.
     *   - render element: (required if "variables" not present) A string that is
     *     the name of the sole renderable element to pass to the theme function.
     *     The string represents the name of the "variable" that will hold the
     *     renderable array inside any optional preprocess or process functions.
     *     Cannot be used with the "variables" item; only one or the other, not
     *     both, can be present in a hook's info array.
     *   - file: The file the implementation resides in. This file will be included
     *     prior to the theme being rendered, to make sure that the function or
     *     preprocess function (as needed) is actually loaded; this makes it
     *     possible to split theme functions out into separate files quite easily.
     *   - path: Override the path of the file to be used. Ordinarily the module or
     *     theme path will be used, but if the file will not be in the default path,
     *     include it here. This path should be relative to the Drupal root
     *     directory.
     *   - template: If specified, this theme implementation is a template, and this
     *     is the template file without an extension. Do not put .tpl.php on this
     *     file; that extension will be added automatically by the default rendering
     *     engine (which is PHPTemplate). If 'path', above, is specified, the
     *     template should also be in this path.
     *   - function: If specified, this will be the function name to invoke for this
     *     implementation. If neither file nor function is specified, a default
     *     function name will be assumed. For example, if a module registers
     *     the 'node' theme hook, 'theme_node' will be assigned to its function.
     *     If the chameleon theme registers the node hook, it will be assigned
     *     'chameleon_node' as its function.
     *   - pattern: A regular expression pattern to be used to allow this theme
     *     implementation to have a dynamic name. The convention is to use __ to
     *     differentiate the dynamic portion of the theme. For example, to allow
     *     forums to be themed individually, the pattern might be: 'forum__'. Then,
     *     when the forum is themed, call:
     *     @code
     *     theme(array('forum__' . $tid, 'forum'), $forum)
     *     @endcode
     *   - preprocess functions: A list of functions used to preprocess this data.
     *     Ordinarily this won't be used; it's automatically filled in. By default,
     *     for a module this will be filled in as template_preprocess_HOOK. For
     *     a theme this will be filled in as phptemplate_preprocess and
     *     phptemplate_preprocess_HOOK as well as themename_preprocess and
     *     themename_preprocess_HOOK.
     *   - override preprocess functions: Set to TRUE when a theme does NOT want the
     *     standard preprocess functions to run. This can be used to give a theme
     *     FULL control over how variables are set. For example, if a theme wants
     *     total control over how certain variables in the page.tpl.php are set,
     *     this can be set to true. Please keep in mind that when this is used
     *     by a theme, that theme becomes responsible for making sure necessary
     *     variables are set.
     *   - type: (automatically derived) Where the theme hook is defined:
     *     'module', 'theme_engine', or 'theme'.
     *   - theme path: (automatically derived) The directory path of the theme or
     *     module, so that it doesn't need to be looked up.
     */
    function hook_theme($existing, $type, $theme, $path) {
      return array(
        'forum_display' => array(
          'variables' => array('forums' => NULL, 'topics' => NULL, 'parents' => NULL, 'tid' => NULL, 'sortby' => NULL, 'forum_per_page' => NULL),
        ),
        'forum_list' => array(
          'variables' => array('forums' => NULL, 'parents' => NULL, 'tid' => NULL),
        ),
        'forum_topic_list' => array(
          'variables' => array('tid' => NULL, 'topics' => NULL, 'sortby' => NULL, 'forum_per_page' => NULL),
        ),
        'forum_icon' => array(
          'variables' => array('new_posts' => NULL, 'num_posts' => 0, 'comment_mode' => 0, 'sticky' => 0),
        ),
        'status_report' => array(
          'render element' => 'requirements',
          'file' => 'system.admin.inc',
        ),
        'system_date_time_settings' => array(
          'render element' => 'form',
          'file' => 'system.admin.inc',
        ),
      );
    }
    
    /**
     * Alter the theme registry information returned from hook_theme().
     *
     * The theme registry stores information about all available theme hooks,
     * including which callback functions those hooks will call when triggered,
     * what template files are exposed by these hooks, and so on.
     *
     * Note that this hook is only executed as the theme cache is re-built.
     * Changes here will not be visible until the next cache clear.
     *
     * The $theme_registry array is keyed by theme hook name, and contains the
     * information returned from hook_theme(), as well as additional properties
     * added by _theme_process_registry().
     *
     * For example:
     * @code
     * $theme_registry['user_profile'] = array(
     *   'variables' => array(
     *     'account' => NULL,
     *   ),
     *   'template' => 'modules/user/user-profile',
     *   'file' => 'modules/user/user.pages.inc',
     *   'type' => 'module',
     *   'theme path' => 'modules/user',
     *   'preprocess functions' => array(
     *     0 => 'template_preprocess',
     *     1 => 'template_preprocess_user_profile',
     *   ),
     * );
     * @endcode
     *
     * @param $theme_registry
     *   The entire cache of theme registry information, post-processing.
     *
     * @see hook_theme()
     * @see _theme_process_registry()
     */
    function hook_theme_registry_alter(&$theme_registry) {
      // Kill the next/previous forum topic navigation links.
      foreach ($theme_registry['forum_topic_navigation']['preprocess functions'] as $key => $value) {
        if ($value = 'template_preprocess_forum_topic_navigation') {
          unset($theme_registry['forum_topic_navigation']['preprocess functions'][$key]);
        }
      }
    }
    
    /**
     * Return the machine-readable name of the theme to use for the current page.
     *
     * This hook can be used to dynamically set the theme for the current page
     * request. It should be used by modules which need to override the theme
     * based on dynamic conditions (for example, a module which allows the theme to
     * be set based on the current user's role). The return value of this hook will
     * be used on all pages except those which have a valid per-page or per-section
     * theme set via a theme callback function in hook_menu(); the themes on those
     * pages can only be overridden using hook_menu_alter().
     *
     * Since only one theme can be used at a time, the last (i.e., highest
     * weighted) module which returns a valid theme name from this hook will
     * prevail.
     *
     * @return
     *   The machine-readable name of the theme that should be used for the current
     *   page request. The value returned from this function will only have an
     *   effect if it corresponds to a currently-active theme on the site.
     */
    function hook_custom_theme() {
      // Allow the user to request a particular theme via a query parameter.
      if (isset($_GET['theme'])) {
        return $_GET['theme'];
      }
    }
    
    /**
     * Register XML-RPC callbacks.
     *
     * This hook lets a module register callback functions to be called when
     * particular XML-RPC methods are invoked by a client.
     *
     * @return
     *   An array which maps XML-RPC methods to Drupal functions. Each array
     *   element is either a pair of method => function or an array with four
     *   entries:
     *   - The XML-RPC method name (for example, module.function).
     *   - The Drupal callback function (for example, module_function).
     *   - The method signature is an array of XML-RPC types. The first element
     *     of this array is the type of return value and then you should write a
     *     list of the types of the parameters. XML-RPC types are the following
     *     (See the types at http://www.xmlrpc.com/spec):
     *       - "boolean": 0 (false) or 1 (true).
     *       - "double": a floating point number (for example, -12.214).
     *       - "int": a integer number (for example,  -12).
     *       - "array": an array without keys (for example, array(1, 2, 3)).
     *       - "struct": an associative array or an object (for example,
     *          array('one' => 1, 'two' => 2)).
     *       - "date": when you return a date, then you may either return a
     *          timestamp (time(), mktime() etc.) or an ISO8601 timestamp. When
     *          date is specified as an input parameter, then you get an object,
     *          which is described in the function xmlrpc_date
     *       - "base64": a string containing binary data, automatically
     *          encoded/decoded automatically.
     *       - "string": anything else, typically a string.
     *   - A descriptive help string, enclosed in a t() function for translation
     *     purposes.
     *   Both forms are shown in the example.
     */
    function hook_xmlrpc() {
      return array(
        'drupal.login' => 'drupal_login',
        array(
          'drupal.site.ping',
          'drupal_directory_ping',
          array('boolean', 'string', 'string', 'string', 'string', 'string'),
          t('Handling ping request'))
      );
    }
    
    /**
     * Alters the definition of XML-RPC methods before they are called.
     *
     * This hook allows modules to modify the callback definition of declared
     * XML-RPC methods, right before they are invoked by a client. Methods may be
     * added, or existing methods may be altered.
     *
     * Note that hook_xmlrpc() supports two distinct and incompatible formats to
     * define a callback, so care must be taken when altering other methods.
     *
     * @param $methods
     *   An asssociative array of method callback definitions, as returned from
     *   hook_xmlrpc() implementations.
     *
     * @see hook_xmlrpc()
     * @see xmlrpc_server()
     */
    function hook_xmlrpc_alter(&$methods) {
      // Directly change a simple method.
      $methods['drupal.login'] = 'mymodule_login';
    
      // Alter complex definitions.
      foreach ($methods as $key => &$method) {
        // Skip simple method definitions.
        if (!is_int($key)) {
          continue;
        }
        // Perform the wanted manipulation.
        if ($method[0] == 'drupal.site.ping') {
          $method[1] = 'mymodule_directory_ping';
        }
      }
    }
    
    /**
     * Log an event message
     *
     * This hook allows modules to route log events to custom destinations, such as
     * SMS, Email, pager, syslog, ...etc.
     *
     * @param $log_entry
     *   An associative array containing the following keys:
     *   - type: The type of message for this entry. For contributed modules, this is
     *     normally the module name. Do not use 'debug', use severity WATCHDOG_DEBUG instead.
     *   - user: The user object for the user who was logged in when the event happened.
     *   - request_uri: The Request URI for the page the event happened in.
     *   - referer: The page that referred the use to the page where the event occurred.
     *   - ip: The IP address where the request for the page came from.
     *   - timestamp: The UNIX timestamp of the date/time the event occurred
     *   - severity: One of the following values as defined in RFC 3164 http://www.faqs.org/rfcs/rfc3164.html
     *     WATCHDOG_EMERGENCY Emergency: system is unusable
     *     WATCHDOG_ALERT     Alert: action must be taken immediately
     *     WATCHDOG_CRITICAL  Critical: critical conditions
     *     WATCHDOG_ERROR     Error: error conditions
     *     WATCHDOG_WARNING   Warning: warning conditions
     *     WATCHDOG_NOTICE    Notice: normal but significant condition
     *     WATCHDOG_INFO      Informational: informational messages
     *     WATCHDOG_DEBUG     Debug: debug-level messages
     *   - link: an optional link provided by the module that called the watchdog() function.
     *   - message: The text of the message to be logged.
     */
    function hook_watchdog(array $log_entry) {
      global $base_url, $language;
    
      $severity_list = array(
        WATCHDOG_EMERGENCY => t('Emergency'),
        WATCHDOG_ALERT     => t('Alert'),
        WATCHDOG_CRITICAL  => t('Critical'),
        WATCHDOG_ERROR     => t('Error'),
        WATCHDOG_WARNING   => t('Warning'),
        WATCHDOG_NOTICE    => t('Notice'),
        WATCHDOG_INFO      => t('Info'),
        WATCHDOG_DEBUG     => t('Debug'),
      );
    
      $to = 'someone@example.com';
      $params = array();
      $params['subject'] = t('[@site_name] @severity_desc: Alert from your web site', array(
        '@site_name' => variable_get('site_name', 'Drupal'),
        '@severity_desc' => $severity_list[$log_entry['severity']],
      ));
    
      $params['message']  = "\nSite:         @base_url";
      $params['message'] .= "\nSeverity:     (@severity) @severity_desc";
      $params['message'] .= "\nTimestamp:    @timestamp";
      $params['message'] .= "\nType:         @type";
      $params['message'] .= "\nIP Address:   @ip";
      $params['message'] .= "\nRequest URI:  @request_uri";
      $params['message'] .= "\nReferrer URI: @referer_uri";
      $params['message'] .= "\nUser:         (@uid) @name";
      $params['message'] .= "\nLink:         @link";
      $params['message'] .= "\nMessage:      \n\n@message";
    
      $params['message'] = t($params['message'], array(
        '@base_url'      => $base_url,
        '@severity'      => $log_entry['severity'],
        '@severity_desc' => $severity_list[$log_entry['severity']],
        '@timestamp'     => format_date($log_entry['timestamp']),
        '@type'          => $log_entry['type'],
        '@ip'            => $log_entry['ip'],
        '@request_uri'   => $log_entry['request_uri'],
        '@referer_uri'   => $log_entry['referer'],
        '@uid'           => $log_entry['user']->uid,
        '@name'          => $log_entry['user']->name,
        '@link'          => strip_tags($log_entry['link']),
        '@message'       => strip_tags($log_entry['message']),
      ));
    
      drupal_mail('emaillog', 'entry', $to, $language, $params);
    }
    
    /**
     * Prepare a message based on parameters; called from drupal_mail().
     *
     * Note that hook_mail(), unlike hook_mail_alter(), is only called on the
     * $module argument to drupal_mail(), not all modules.
     *
     * @param $key
     *   An identifier of the mail.
     * @param $message
     *   An array to be filled in. Elements in this array include:
     *   - id: An ID to identify the mail sent. Look at module source code
     *     or drupal_mail() for possible id values.
     *   - to: The address or addresses the message will be sent to. The
     *     formatting of this string must comply with RFC 2822.
     *   - subject: Subject of the e-mail to be sent. This must not contain any
     *     newline characters, or the mail may not be sent properly. drupal_mail()
     *     sets this to an empty string when the hook is invoked.
     *   - body: An array of lines containing the message to be sent. Drupal will
     *     format the correct line endings for you. drupal_mail() sets this to an
     *     empty array when the hook is invoked.
     *   - from: The address the message will be marked as being from, which is
     *     set by drupal_mail() to either a custom address or the site-wide
     *     default email address when the hook is invoked.
     *   - headers: Associative array containing mail headers, such as From,
     *     Sender, MIME-Version, Content-Type, etc. drupal_mail() pre-fills
     *     several headers in this array.
     * @param $params
     *   An array of parameters supplied by the caller of drupal_mail().
     */
    function hook_mail($key, &$message, $params) {
      $account = $params['account'];
      $context = $params['context'];
      $variables = array(
        '%site_name' => variable_get('site_name', 'Drupal'),
        '%username' => format_username($account),
      );
      if ($context['hook'] == 'taxonomy') {
        $entity = $params['entity'];
        $vocabulary = taxonomy_vocabulary_load($entity->vid);
        $variables += array(
          '%term_name' => $entity->name,
          '%term_description' => $entity->description,
          '%term_id' => $entity->tid,
          '%vocabulary_name' => $vocabulary->name,
          '%vocabulary_description' => $vocabulary->description,
          '%vocabulary_id' => $vocabulary->vid,
        );
      }
    
      // Node-based variable translation is only available if we have a node.
      if (isset($params['node'])) {
        $node = $params['node'];
        $variables += array(
          '%uid' => $node->uid,
          '%node_url' => url('node/' . $node->nid, array('absolute' => TRUE)),
          '%node_type' => node_type_get_name($node),
          '%title' => $node->title,
          '%teaser' => $node->teaser,
          '%body' => $node->body,
        );
      }
      $subject = strtr($context['subject'], $variables);
      $body = strtr($context['message'], $variables);
      $message['subject'] .= str_replace(array("\r", "\n"), '', $subject);
      $message['body'][] = drupal_html_to_text($body);
    }
    
    /**
     * Add a list of cache tables to be cleared.
     *
     * This hook allows your module to add cache table names to the list of cache
     * tables that will be cleared by the Clear button on the Performance page or
     * whenever drupal_flush_all_caches is invoked.
     *
     * @return
     *   An array of cache table names.
     *
     * @see drupal_flush_all_caches()
     */
    function hook_flush_caches() {
      return array('cache_example');
    }
    
    /**
     * Perform necessary actions after modules are installed.
     *
     * This function differs from hook_install() in that it gives all other modules
     * a chance to perform actions when a module is installed, whereas
     * hook_install() is only called on the module actually being installed. See
     * module_enable() for a detailed description of the order in which install and
     * enable hooks are invoked.
     *
     * @param $modules
     *   An array of the installed modules.
     *
     * @see module_enable()
     * @see hook_modules_enabled()
     * @see hook_install()
     */
    function hook_modules_installed($modules) {
      if (in_array('lousy_module', $modules)) {
        variable_set('lousy_module_conflicting_variable', FALSE);
      }
    }
    
    /**
     * Perform necessary actions after modules are enabled.
     *
     * This function differs from hook_enable() in that it gives all other modules a
     * chance to perform actions when modules are enabled, whereas hook_enable() is
     * only called on the module actually being enabled. See module_enable() for a
     * detailed description of the order in which install and enable hooks are
     * invoked.
     *
     * @param $modules
     *   An array of the enabled modules.
     *
     * @see hook_enable()
     * @see hook_modules_installed()
     * @see module_enable()
     */
    function hook_modules_enabled($modules) {
      if (in_array('lousy_module', $modules)) {
        drupal_set_message(t('mymodule is not compatible with lousy_module'), 'error');
        mymodule_disable_functionality();
      }
    }
    
    /**
     * Perform necessary actions after modules are disabled.
     *
     * This function differs from hook_disable() in that it gives all other modules
     * a chance to perform actions when modules are disabled, whereas hook_disable()
     * is only called on the module actually being disabled.
     *
     * @param $modules
     *   An array of the disabled modules.
     *
     * @see hook_disable()
     * @see hook_modules_uninstalled()
     */
    function hook_modules_disabled($modules) {
      if (in_array('lousy_module', $modules)) {
        mymodule_enable_functionality();
      }
    }
    
    /**
     * Perform necessary actions after modules are uninstalled.
     *
     * This function differs from hook_uninstall() in that it gives all other
     * modules a chance to perform actions when a module is uninstalled, whereas
     * hook_uninstall() is only called on the module actually being uninstalled.
     *
     * It is recommended that you implement this hook if your module stores
     * data that may have been set by other modules.
     *
     * @param $modules
     *   An array of the uninstalled modules.
     *
     * @see hook_uninstall()
     * @see hook_modules_disabled()
     */
    function hook_modules_uninstalled($modules) {
      foreach ($modules as $module) {
        db_delete('mymodule_table')
          ->condition('module', $module)
          ->execute();
      }
      mymodule_cache_rebuild();
    }
    
    /**
     * Registers PHP stream wrapper implementations associated with a module.
     *
     * Provide a facility for managing and querying user-defined stream wrappers
     * in PHP. PHP's internal stream_get_wrappers() doesn't return the class
     * registered to handle a stream, which we need to be able to find the handler
     * for class instantiation.
     *
     * If a module registers a scheme that is already registered with PHP, it will
     * be unregistered and replaced with the specified class.
     *
     * @return
     *   A nested array, keyed first by scheme name ("public" for "public://"),
     *   then keyed by the following values:
     *   - 'name' A short string to name the wrapper.
     *   - 'class' A string specifying the PHP class that implements the
     *     DrupalStreamWrapperInterface interface.
     *   - 'description' A string with a short description of what the wrapper does.
     *   - 'type' (Optional) A bitmask of flags indicating what type of streams this
     *     wrapper will access - local or remote, readable and/or writeable, etc.
     *     Many shortcut constants are defined in stream_wrappers.inc. Defaults to
     *     STREAM_WRAPPERS_NORMAL which includes all of these bit flags:
     *     - STREAM_WRAPPERS_READ
     *     - STREAM_WRAPPERS_WRITE
     *     - STREAM_WRAPPERS_VISIBLE
     *
     * @see file_get_stream_wrappers()
     * @see hook_stream_wrappers_alter()
     * @see system_stream_wrappers()
     */
    function hook_stream_wrappers() {
      return array(
        'public' => array(
          'name' => t('Public files'),
          'class' => 'DrupalPublicStreamWrapper',
          'description' => t('Public local files served by the webserver.'),
          'type' => STREAM_WRAPPERS_LOCAL_NORMAL,
        ),
        'private' => array(
          'name' => t('Private files'),
          'class' => 'DrupalPrivateStreamWrapper',
          'description' => t('Private local files served by Drupal.'),
          'type' => STREAM_WRAPPERS_LOCAL_NORMAL,
        ),
        'temp' => array(
          'name' => t('Temporary files'),
          'class' => 'DrupalTempStreamWrapper',
          'description' => t('Temporary local files for upload and previews.'),
          'type' => STREAM_WRAPPERS_LOCAL_HIDDEN,
        ),
        'cdn' => array(
          'name' => t('Content delivery network files'),
          'class' => 'MyModuleCDNStreamWrapper',
          'description' => t('Files served by a content delivery network.'),
          // 'type' can be omitted to use the default of STREAM_WRAPPERS_NORMAL
        ),
        'youtube' => array(
          'name' => t('YouTube video'),
          'class' => 'MyModuleYouTubeStreamWrapper',
          'description' => t('Video streamed from YouTube.'),
          // A module implementing YouTube integration may decide to support using
          // the YouTube API for uploading video, but here, we assume that this
          // particular module only supports playing YouTube video.
          'type' => STREAM_WRAPPERS_READ_VISIBLE,
        ),
      );
    }
    
    /**
     * Alters the list of PHP stream wrapper implementations.
     *
     * @see file_get_stream_wrappers()
     * @see hook_stream_wrappers()
     */
    function hook_stream_wrappers_alter(&$wrappers) {
      // Change the name of private files to reflect the performance.
      $wrappers['private']['name'] = t('Slow files');
    }
    
    /**
     * Load additional information into file objects.
     *
     * file_load_multiple() calls this hook to allow modules to load
     * additional information into each file.
     *
     * @param $files
     *   An array of file objects, indexed by fid.
     *
     * @see file_load_multiple()
     * @see upload_file_load()
     */
    function hook_file_load($files) {
      // Add the upload specific data into the file object.
      $result = db_query('SELECT * FROM {upload} u WHERE u.fid IN (:fids)', array(':fids' => array_keys($files)))->fetchAll(PDO::FETCH_ASSOC);
      foreach ($result as $record) {
        foreach ($record as $key => $value) {
          $files[$record['fid']]->$key = $value;
        }
      }
    }
    
    /**
     * Check that files meet a given criteria.
     *
     * This hook lets modules perform additional validation on files. They're able
     * to report a failure by returning one or more error messages.
     *
     * @param $file
     *   The file object being validated.
     * @return
     *   An array of error messages. If there are no problems with the file return
     *   an empty array.
     *
     * @see file_validate()
     */
    function hook_file_validate($file) {
      $errors = array();
    
      if (empty($file->filename)) {
        $errors[] = t("The file's name is empty. Please give a name to the file.");
      }
      if (strlen($file->filename) > 255) {
        $errors[] = t("The file's name exceeds the 255 characters limit. Please rename the file and try again.");
      }
    
      return $errors;
    }
    
    /**
     * Act on a file being inserted or updated.
     *
     * This hook is called when a file has been added to the database. The hook
     * doesn't distinguish between files created as a result of a copy or those
     * created by an upload.
     *
     * @param $file
     *   The file that has just been created.
     *
     * @see file_save()
     */
    function hook_file_presave($file) {
      // Change the file timestamp to an hour prior.
      $file->timestamp -= 3600;
    }
    
    /**
     * Respond to a file being added.
     *
     * This hook is called before a file has been added to the database. The hook
     * doesn't distinguish between files created as a result of a copy or those
     * created by an upload.
     *
     * @param $file
     *   The file that is about to be saved.
     *
     * @see file_save()
     */
    function hook_file_insert($file) {
    
    }
    
    /**
     * Respond to a file being updated.
     *
     * This hook is called when file_save() is called on an existing file.
     *
     * @param $file
     *   The file that has just been updated.
     *
     * @see file_save()
     */
    function hook_file_update($file) {
    
    }
    
    /**
     * Respond to a file that has been copied.
     *
     * @param $file
     *   The newly copied file object.
     * @param $source
     *   The original file before the copy.
     *
     * @see file_copy()
     */
    function hook_file_copy($file, $source) {
    
    }
    
    /**
     * Respond to a file that has been moved.
     *
     * @param $file
     *   The updated file object after the move.
     * @param $source
     *   The original file object before the move.
     *
     * @see file_move()
     */
    function hook_file_move($file, $source) {
    
    }
    
    /**
     * Respond to a file being deleted.
     *
     * @param $file
     *   The file that has just been deleted.
     *
     * @see file_delete()
     * @see upload_file_delete()
     */
    function hook_file_delete($file) {
      // Delete all information associated with the file.
      db_delete('upload')->condition('fid', $file->fid)->execute();
    }
    
    /**
     * Control access to private file downloads and specify HTTP headers.
     *
     * This hook allows modules enforce permissions on file downloads when the
     * private file download method is selected. Modules can also provide headers
     * to specify information like the file's name or MIME type.
     *
     * @param $uri
     *   The URI of the file.
     * @return
     *   If the user does not have permission to access the file, return -1. If the
     *   user has permission, return an array with the appropriate headers. If the
     *   file is not controlled by the current module, the return value should be
     *   NULL.
     *
     * @see file_download()
     * @see upload_file_download()
     */
    function hook_file_download($uri) {
      // Check if the file is controlled by the current module.
      if (!file_prepare_directory($uri)) {
        $uri = FALSE;
      }
      $result = db_query("SELECT f.* FROM {file_managed} f INNER JOIN {upload} u ON f.fid = u.fid WHERE uri = :uri", array('uri' => $uri));
      foreach ($result as $file) {
        if (!user_access('view uploaded files')) {
          return -1;
        }
        return array(
          'Content-Type' => $file->filemime,
          'Content-Length' => $file->filesize,
        );
      }
    }
    
    /**
     * Alter the URL to a file.
     *
     * This hook is called from file_create_url(), and  is called fairly
     * frequently (10+ times per page), depending on how many files there are in a
     * given page.
     * If CSS and JS aggregation are disabled, this can become very frequently
     * (50+ times per page) so performance is critical.
     *
     * This function should alter the URI, if it wants to rewrite the file URL.
     *
     * @param $uri
     *   The URI to a file for which we need an external URL, or the path to a
     *   shipped file.
     */
    function hook_file_url_alter(&$uri) {
      global $user;
    
      // User 1 will always see the local file in this example.
      if ($user->uid == 1) {
        return;
      }
    
      $cdn1 = 'http://cdn1.example.com';
      $cdn2 = 'http://cdn2.example.com';
      $cdn_extensions = array('css', 'js', 'gif', 'jpg', 'jpeg', 'png');
    
      // Most CDNs don't support private file transfers without a lot of hassle,
      // so don't support this in the common case.
      $schemes = array('public');
    
      $scheme = file_uri_scheme($uri);
    
      // Only serve shipped files and public created files from the CDN.
      if (!$scheme || in_array($scheme, $schemes)) {
        // Shipped files.
        if (!$scheme) {
          $path = $uri;
        }
        // Public created files.
        else {
          $wrapper = file_stream_wrapper_get_instance_by_scheme($scheme);
          $path = $wrapper->getDirectoryPath() . '/' . file_uri_target($uri);
        }
    
        // Clean up Windows paths.
        $path = str_replace('\\', '/', $path);
    
        // Serve files with one of the CDN extensions from CDN 1, all others from
        // CDN 2.
        $pathinfo = pathinfo($path);
        if (isset($pathinfo['extension']) && in_array($pathinfo['extension'], $cdn_extensions)) {
          $uri = $cdn1 . '/' . $path;
        }
        else {
          $uri = $cdn2 . '/' . $path;
        }
      }
    }
    
    /**
     * Check installation requirements and do status reporting.
     *
     * This hook has two closely related uses, determined by the $phase argument:
     * checking installation requirements ($phase == 'install')
     * and status reporting ($phase == 'runtime').
     *
     * Note that this hook, like all others dealing with installation and updates,
     * must reside in a module_name.install file, or it will not properly abort
     * the installation of the module if a critical requirement is missing.
     *
     * During the 'install' phase, modules can for example assert that
     * library or server versions are available or sufficient.
     * Note that the installation of a module can happen during installation of
     * Drupal itself (by install.php) with an installation profile or later by hand.
     * As a consequence, install-time requirements must be checked without access
     * to the full Drupal API, because it is not available during install.php.
     * For localization you should for example use $t = get_t() to
     * retrieve the appropriate localization function name (t() or st()).
     * If a requirement has a severity of REQUIREMENT_ERROR, install.php will abort
     * or at least the module will not install.
     * Other severity levels have no effect on the installation.
     * Module dependencies do not belong to these installation requirements,
     * but should be defined in the module's .info file.
     *
     * The 'runtime' phase is not limited to pure installation requirements
     * but can also be used for more general status information like maintenance
     * tasks and security issues.
     * The returned 'requirements' will be listed on the status report in the
     * administration section, with indication of the severity level.
     * Moreover, any requirement with a severity of REQUIREMENT_ERROR severity will
     * result in a notice on the the administration overview page.
     *
     * @param $phase
     *   The phase in which requirements are checked:
     *   - install: The module is being installed.
     *   - update: The module is enabled and update.php is run.
     *   - runtime: The runtime requirements are being checked and shown on the
     *     status report page.
     *
     * @return
     *   A keyed array of requirements. Each requirement is itself an array with
     *   the following items:
     *   - title: The name of the requirement.
     *   - value: The current value (e.g., version, time, level, etc). During
     *     install phase, this should only be used for version numbers, do not set
     *     it if not applicable.
     *   - description: The description of the requirement/status.
     *   - severity: The requirement's result/severity level, one of:
     *     - REQUIREMENT_INFO: For info only.
     *     - REQUIREMENT_OK: The requirement is satisfied.
     *     - REQUIREMENT_WARNING: The requirement failed with a warning.
     *     - REQUIREMENT_ERROR: The requirement failed with an error.
     */
    function hook_requirements($phase) {
      $requirements = array();
      // Ensure translations don't break at install time
      $t = get_t();
    
      // Report Drupal version
      if ($phase == 'runtime') {
        $requirements['drupal'] = array(
          'title' => $t('Drupal'),
          'value' => VERSION,
          'severity' => REQUIREMENT_INFO
        );
      }
    
      // Test PHP version
      $requirements['php'] = array(
        'title' => $t('PHP'),
        'value' => ($phase == 'runtime') ? l(phpversion(), 'admin/logs/status/php') : phpversion(),
      );
      if (version_compare(phpversion(), DRUPAL_MINIMUM_PHP) < 0) {
        $requirements['php']['description'] = $t('Your PHP installation is too old. Drupal requires at least PHP %version.', array('%version' => DRUPAL_MINIMUM_PHP));
        $requirements['php']['severity'] = REQUIREMENT_ERROR;
      }
    
      // Report cron status
      if ($phase == 'runtime') {
        $cron_last = variable_get('cron_last');
    
        if (is_numeric($cron_last)) {
          $requirements['cron']['value'] = $t('Last run !time ago', array('!time' => format_interval(REQUEST_TIME - $cron_last)));
        }
        else {
          $requirements['cron'] = array(
            'description' => $t('Cron has not run. It appears cron jobs have not been setup on your system. Check the help pages for <a href="@url">configuring cron jobs</a>.', array('@url' => 'http://drupal.org/cron')),
            'severity' => REQUIREMENT_ERROR,
            'value' => $t('Never run'),
          );
        }
    
        $requirements['cron']['description'] .= ' ' . t('You can <a href="@cron">run cron manually</a>.', array('@cron' => url('admin/logs/status/run-cron')));
    
        $requirements['cron']['title'] = $t('Cron maintenance tasks');
      }
    
      return $requirements;
    }
    
    /**
     * Define the current version of the database schema.
     *
     * A Drupal schema definition is an array structure representing one or
     * more tables and their related keys and indexes. A schema is defined by
     * hook_schema() which must live in your module's .install file.
     *
     * By implementing hook_schema() and specifying the tables your module
     * declares, you can easily create and drop these tables on all
     * supported database engines. You don't have to deal with the
     * different SQL dialects for table creation and alteration of the
     * supported database engines.
     *
     * See the Schema API Handbook at http://drupal.org/node/146843 for
     * details on schema definition structures.
     *
     * @return
     *   A schema definition structure array. For each element of the
     *   array, the key is a table name and the value is a table structure
     *   definition.
     *
     * @ingroup schemaapi
     */
    function hook_schema() {
      $schema['node'] = array(
        // example (partial) specification for table "node"
        'description' => 'The base table for nodes.',
        'fields' => array(
          'nid' => array(
            'description' => 'The primary identifier for a node.',
            'type' => 'serial',
            'unsigned' => TRUE,
            'not null' => TRUE),
          'vid' => array(
            'description' => 'The current {node_revision}.vid version identifier.',
            'type' => 'int',
            'unsigned' => TRUE,
            'not null' => TRUE,
            'default' => 0),
          'type' => array(
            'description' => 'The {node_type} of this node.',
            'type' => 'varchar',
            'length' => 32,
            'not null' => TRUE,
            'default' => ''),
          'title' => array(
            'description' => 'The title of this node, always treated as non-markup plain text.',
            'type' => 'varchar',
            'length' => 255,
            'not null' => TRUE,
            'default' => ''),
          ),
        'indexes' => array(
          'node_changed'        => array('changed'),
          'node_created'        => array('created'),
          ),
        'unique keys' => array(
          'nid_vid' => array('nid', 'vid'),
          'vid'     => array('vid')
          ),
        'foreign keys' => array(
          'node_revision' => array(
            'table' => 'node_revision',
            'columns' => array('vid' => 'vid'),
            ),
          'node_author' => array(
            'table' => 'users',
            'columns' => array('uid' => 'uid')
            ),
           ),
        'primary key' => array('nid'),
      );
      return $schema;
    }
    
    /**
     * Perform alterations to existing database schemas.
     *
     * When a module modifies the database structure of another module (by
     * changing, adding or removing fields, keys or indexes), it should
     * implement hook_schema_alter() to update the default $schema to take its
     * changes into account.
     *
     * See hook_schema() for details on the schema definition structure.
     *
     * @param $schema
     *   Nested array describing the schemas for all modules.
     */
    function hook_schema_alter(&$schema) {
      // Add field to existing schema.
      $schema['users']['fields']['timezone_id'] = array(
        'type' => 'int',
        'not null' => TRUE,
        'default' => 0,
        'description' => 'Per-user timezone configuration.',
      );
    }
    
    /**
     * Perform alterations to a structured query.
     *
     * Structured (aka dynamic) queries that have tags associated may be altered by any module
     * before the query is executed.
     *
     * @param $query
     *   A Query object describing the composite parts of a SQL query.
     *
     * @see hook_query_TAG_alter()
     * @see node_query_node_access_alter()
     * @see QueryAlterableInterface
     * @see SelectQueryInterface
     */
    function hook_query_alter(QueryAlterableInterface $query) {
      if ($query->hasTag('micro_limit')) {
        $query->range(0, 2);
      }
    }
    
    /**
     * Perform alterations to a structured query for a given tag.
     *
     * @param $query
     *   An Query object describing the composite parts of a SQL query.
     *
     * @see hook_query_alter()
     * @see node_query_node_access_alter()
     * @see QueryAlterableInterface
     * @see SelectQueryInterface
     */
    function hook_query_TAG_alter(QueryAlterableInterface $query) {
      // Skip the extra expensive alterations if site has no node access control modules.
      if (!node_access_view_all_nodes()) {
        // Prevent duplicates records.
        $query->distinct();
        // The recognized operations are 'view', 'update', 'delete'.
        if (!$op = $query->getMetaData('op')) {
          $op = 'view';
        }
        // Skip the extra joins and conditions for node admins.
        if (!user_access('bypass node access')) {
          // The node_access table has the access grants for any given node.
          $access_alias = $query->join('node_access', 'na', '%alias.nid = n.nid');
          $or = db_or();
          // If any grant exists for the specified user, then user has access to the node for the specified operation.
          foreach (node_access_grants($op, $query->getMetaData('account')) as $realm => $gids) {
            foreach ($gids as $gid) {
              $or->condition(db_and()
                ->condition($access_alias . '.gid', $gid)
                ->condition($access_alias . '.realm', $realm)
              );
            }
          }
    
          if (count($or->conditions())) {
            $query->condition($or);
          }
    
          $query->condition($access_alias . 'grant_' . $op, 1, '>=');
        }
      }
    }
    
    /**
     * Perform setup tasks when the module is installed.
     *
     * If the module implements hook_schema(), the database tables will
     * be created before this hook is fired.
     *
     * This hook will only be called the first time a module is enabled or after it
     * is re-enabled after being uninstalled. The module's schema version will be
     * set to the module's greatest numbered update hook. Because of this, anytime a
     * hook_update_N() is added to the module, this function needs to be updated to
     * reflect the current version of the database schema.
     *
     * See the Schema API documentation at
     * @link http://drupal.org/node/146843 http://drupal.org/node/146843 @endlink
     * for details on hook_schema and how database tables are defined.
     *
     * Note that since this function is called from a full bootstrap, all functions
     * (including those in modules enabled by the current page request) are
     * available when this hook is called. Use cases could be displaying a user
     * message, or calling a module function necessary for initial setup, etc.
     *
     * Please be sure that anything added or modified in this function that can
     * be removed during uninstall should be removed with hook_uninstall().
     *
     * @see hook_schema()
     * @see module_enable()
     * @see hook_enable()
     * @see hook_disable()
     * @see hook_uninstall()
     * @see hook_modules_installed()
     */
    function hook_install() {
      // Populate the default {node_access} record.
      db_insert('node_access')
        ->fields(array(
          'nid' => 0,
          'gid' => 0,
          'realm' => 'all',
          'grant_view' => 1,
          'grant_update' => 0,
          'grant_delete' => 0,
        ))
        ->execute();
    }
    
    /**
     * Perform a single update.
     *
     * For each patch which requires a database change add a new hook_update_N()
     * which will be called by update.php. The database updates are numbered
     * sequentially according to the version of Drupal you are compatible with.
     *
     * Schema updates should adhere to the Schema API:
     * @link http://drupal.org/node/150215 http://drupal.org/node/150215 @endlink
     *
     * Database updates consist of 3 parts:
     * - 1 digit for Drupal core compatibility
     * - 1 digit for your module's major release version (e.g. is this the 5.x-1.* (1) or 5.x-2.* (2) series of your module?)
     * - 2 digits for sequential counting starting with 00
     *
     * The 2nd digit should be 0 for initial porting of your module to a new Drupal
     * core API.
     *
     * Examples:
     * - mymodule_update_5200()
     *   - This is the first update to get the database ready to run mymodule 5.x-2.*.
     * - mymodule_update_6000()
     *   - This is the required update for mymodule to run with Drupal core API 6.x.
     * - mymodule_update_6100()
     *   - This is the first update to get the database ready to run mymodule 6.x-1.*.
     * - mymodule_update_6200()
     *   - This is the first update to get the database ready to run mymodule 6.x-2.*.
     *     Users can directly update from 5.x-2.* to 6.x-2.* and they get all 60XX
     *     and 62XX updates, but not 61XX updates, because those reside in the
     *     6.x-1.x branch only.
     *
     * A good rule of thumb is to remove updates older than two major releases of
     * Drupal. See hook_update_last_removed() to notify Drupal about the removals.
     *
     * Never renumber update functions.
     *
     * Further information about releases and release numbers:
     * - @link http://drupal.org/handbook/version-info http://drupal.org/handbook/version-info @endlink
     * - @link http://drupal.org/node/93999 http://drupal.org/node/93999 @endlink (Overview of contributions branches and tags)
     * - @link http://drupal.org/handbook/cvs/releases http://drupal.org/handbook/cvs/releases @endlink
     *
     * Implementations of this hook should be placed in a mymodule.install file in
     * the same directory as mymodule.module. Drupal core's updates are implemented
     * using the system module as a name and stored in database/updates.inc.
     *
     * If your update task is potentially time-consuming, you'll need to implement a
     * multipass update to avoid PHP timeouts. Multipass updates use the $sandbox
     * parameter provided by the batch API (normally, $context['sandbox']) to store
     * information between successive calls, and the $sandbox['#finished'] value
     * to provide feedback regarding completion level.
     *
     * See the batch operations page for more information on how to use the batch API:
     * @link http://drupal.org/node/180528 http://drupal.org/node/180528 @endlink
     *
     * @param $sandbox
     *   Stores information for multipass updates. See above for more information.
     *
     * @throws DrupalUpdateException, PDOException
     *   In case of error, update hooks should throw an instance of DrupalUpdateException
     *   with a meaningful message for the user. If a database query fails for whatever
     *   reason, it will throw a PDOException.
     *
     * @return
     *   Optionally update hooks may return a translated string that will be displayed
     *   to the user. If no message is returned, no message will be presented to the
     *   user.
     */
    function hook_update_N(&$sandbox) {
      // For non-multipass updates, the signature can simply be;
      // function hook_update_N() {
    
      // For most updates, the following is sufficient.
      db_add_field('mytable1', 'newcol', array('type' => 'int', 'not null' => TRUE, 'description' => 'My new integer column.'));
    
      // However, for more complex operations that may take a long time,
      // you may hook into Batch API as in the following example.
    
      // Update 3 users at a time to have an exclamation point after their names.
      // (They're really happy that we can do batch API in this hook!)
      if (!isset($sandbox['progress'])) {
        $sandbox['progress'] = 0;
        $sandbox['current_uid'] = 0;
        // We'll -1 to disregard the uid 0...
        $sandbox['max'] = db_query('SELECT COUNT(DISTINCT uid) FROM {users}')->fetchField() - 1;
      }
    
      $users = db_select('users', 'u')
        ->fields('u', array('uid', 'name'))
        ->condition('uid', $sandbox['current_uid'], '>')
        ->range(0, 3)
        ->orderBy('uid', 'ASC')
        ->execute();
    
      foreach ($users as $user) {
        $user->name .= '!';
        db_update('users')
          ->fields(array('name' => $user->name))
          ->condition('uid', $user->uid)
          ->execute();
    
        $sandbox['progress']++;
        $sandbox['current_uid'] = $user->uid;
      }
    
      $sandbox['#finished'] = empty($sandbox['max']) ? 1 : ($sandbox['progress'] / $sandbox['max']);
    
      // To display a message to the user when the update is completed, return it.
      // If you do not want to display a completion message, simply return nothing.
      return t('The update did what it was supposed to do.');
    
      // In case of an error, simply throw an exception with an error message.
      throw new DrupalUpdateException('Something went wrong; here is what you should do.');
    }
    
    /**
     * Return an array of information about module update dependencies.
     *
     * This can be used to indicate update functions from other modules that your
     * module's update functions depend on, or vice versa. It is used by the update
     * system to determine the appropriate order in which updates should be run, as
     * well as to search for missing dependencies.
     *
     * Implementations of this hook should be placed in a mymodule.install file in
     * the same directory as mymodule.module.
     *
     * @return
     *   A multidimensional array containing information about the module update
     *   dependencies. The first two levels of keys represent the module and update
     *   number (respectively) for which information is being returned, and the
     *   value is an array of information about that update's dependencies. Within
     *   this array, each key represents a module, and each value represents the
     *   number of an update function within that module. In the event that your
     *   update function depends on more than one update from a particular module,
     *   you should always list the highest numbered one here (since updates within
     *   a given module always run in numerical order).
     *
     * @see update_resolve_dependencies()
     * @see hook_update_N()
     */
    function hook_update_dependencies() {
      // Indicate that the mymodule_update_7000() function provided by this module
      // must run after the another_module_update_7002() function provided by the
      // 'another_module' module.
      $dependencies['mymodule'][7000] = array(
        'another_module' => 7002,
      );
      // Indicate that the mymodule_update_7001() function provided by this module
      // must run before the yet_another_module_update_7004() function provided by
      // the 'yet_another_module' module. (Note that declaring dependencies in this
      // direction should be done only in rare situations, since it can lead to the
      // following problem: If a site has already run the yet_another_module
      // module's database updates before it updates its codebase to pick up the
      // newest mymodule code, then the dependency declared here will be ignored.)
      $dependencies['yet_another_module'][7004] = array(
        'mymodule' => 7001,
      );
      return $dependencies;
    }
    
    /**
     * Return a number which is no longer available as hook_update_N().
     *
     * If you remove some update functions from your mymodule.install file, you
     * should notify Drupal of those missing functions. This way, Drupal can
     * ensure that no update is accidentally skipped.
     *
     * Implementations of this hook should be placed in a mymodule.install file in
     * the same directory as mymodule.module.
     *
     * @return
     *   An integer, corresponding to hook_update_N() which has been removed from
     *   mymodule.install.
     *
     * @see hook_update_N()
     */
    function hook_update_last_removed() {
      // We've removed the 5.x-1.x version of mymodule, including database updates.
      // The next update function is mymodule_update_5200().
      return 5103;
    }
    
    /**
     * Remove any information that the module sets.
     *
     * The information that the module should remove includes:
     * - variables that the module has set using variable_set() or system_settings_form()
     * - modifications to existing tables
     *
     * The module should not remove its entry from the {system} table. Database
     * tables defined by hook_schema() will be removed automatically.
     *
     * The uninstall hook will fire when the module gets uninstalled but before the
     * module's database tables are removed, allowing your module to query its own
     * tables during this routine.
     *
     * @see hook_install()
     * @see hook_schema()
     * @see hook_disable()
     * @see hook_modules_uninstalled()
     */
    function hook_uninstall() {
      variable_del('upload_file_types');
    }
    
    /**
     * Perform necessary actions after module is enabled.
     *
     * The hook is called every time the module is enabled.
     *
     * @see module_enable()
     * @see hook_install()
     * @see hook_modules_enabled()
     */
    function hook_enable() {
      mymodule_cache_rebuild();
    }
    
    /**
     * Perform necessary actions before module is disabled.
     *
     * The hook is called every time the module is disabled.
     *
     * @see hook_uninstall()
     * @see hook_modules_disabled()
     */
    function hook_disable() {
      mymodule_cache_rebuild();
    }
    
    /**
     * Perform necessary alterations to the list of files parsed by the registry.
     *
     * Modules can manually modify the list of files before the registry parses
     * them. The $modules array provides the .info file information, which includes
     * the list of files registered to each module. Any files in the list can then
     * be added to the list of files that the registry will parse, or modify
     * attributes of a file.
     *
     * A necessary alteration made by the core SimpleTest module is to force .test
     * files provided by disabled modules into the list of files parsed by the
     * registry.
     *
     * @param $files
     *   List of files to be parsed by the registry. The list will contain
     *   files found in each enabled module's info file and the core includes
     *   directory. The array is keyed by the file path and contains an array of
     *   the related module's name and weight as used internally by
     *   _registry_update() and related functions.
     *
     *   For example:
     *   @code
     *     $files["modules/system/system.module"] = array(
     *       'module' => 'system',
     *       'weight' => 0,
     *     );
     *   @endcode
     * @param $modules
     *   An array containing all module information stored in the {system} table.
     *   Each element of the array also contains the module's .info file
     *   information in the property 'info'. An additional 'dir' property has been
     *   added to the module information which provides the path to the directory
     *   in which the module resides. The example shows how to take advantage of
     *   both properties.
     *
     * @see _registry_update()
     * @see simpletest_test_get_all()
     */
    function hook_registry_files_alter(&$files, $modules) {
      foreach ($modules as $module) {
        // Only add test files for disabled modules, as enabled modules should
        // already include any test files they provide.
        if (!$module->status) {
          $dir = $module->dir;
          foreach ($module->info['files'] as $file) {
            if (substr($file, -5) == '.test') {
              $files["$dir/$file"] = array('module' => $module->name, 'weight' => $module->weight);
            }
          }
        }
      }
    }
    
    /**
     * Return an array of tasks to be performed by an installation profile.
     *
     * Any tasks you define here will be run, in order, after the installer has
     * finished the site configuration step but before it has moved on to the
     * final import of languages and the end of the installation. You can have any
     * number of custom tasks to perform during this phase.
     *
     * Each task you define here corresponds to a callback function which you must
     * separately define and which is called when your task is run. This function
     * will receive the global installation state variable, $install_state, as
     * input, and has the opportunity to access or modify any of its settings. See
     * the install_state_defaults() function in the installer for the list of
     * $install_state settings used by Drupal core.
     *
     * At the end of your task function, you can indicate that you want the
     * installer to pause and display a page to the user by returning any themed
     * output that should be displayed on that page (but see below for tasks that
     * use the form API or batch API; the return values of these task functions are
     * handled differently). You should also use drupal_set_title() within the task
     * callback function to set a custom page title. For some tasks, however, you
     * may want to simply do some processing and pass control to the next task
     * without ending the page request; to indicate this, simply do not send back
     * a return value from your task function at all. This can be used, for
     * example, by installation profiles that need to configure certain site
     * settings in the database without obtaining any input from the user.
     *
     * The task function is treated specially if it defines a form or requires
     * batch processing; in that case, you should return either the form API
     * definition or batch API array, as appropriate. See below for more
     * information on the 'type' key that you must define in the task definition
     * to inform the installer that your task falls into one of those two
     * categories. It is important to use these APIs directly, since the installer
     * may be run non-interactively (for example, via a command line script), all
     * in one page request; in that case, the installer will automatically take
     * care of submitting forms and processing batches correctly for both types of
     * installations. You can inspect the $install_state['interactive'] boolean to
     * see whether or not the current installation is interactive, if you need
     * access to this information.
     *
     * Remember that a user installing Drupal interactively will be able to reload
     * an installation page multiple times, so you should use variable_set() and
     * variable_get() if you are collecting any data that you need to store and
     * inspect later. It is important to remove any temporary variables using
     * variable_del() before your last task has completed and control is handed
     * back to the installer.
     *
     * @return
     *   A keyed array of tasks the profile will perform during the final stage of
     *   the installation. Each key represents the name of a function (usually a
     *   function defined by this profile, although that is not strictly required)
     *   that is called when that task is run. The values are associative arrays
     *   containing the following key-value pairs (all of which are optional):
     *     - 'display_name'
     *       The human-readable name of the task. This will be displayed to the
     *       user while the installer is running, along with a list of other tasks
     *       that are being run. Leave this unset to prevent the task from
     *       appearing in the list.
     *     - 'display'
     *       This is a boolean which can be used to provide finer-grained control
     *       over whether or not the task will display. This is mostly useful for
     *       tasks that are intended to display only under certain conditions; for
     *       these tasks, you can set 'display_name' to the name that you want to
     *       display, but then use this boolean to hide the task only when certain
     *       conditions apply.
     *     - 'type'
     *       A string representing the type of task. This parameter has three
     *       possible values:
     *       - 'normal': This indicates that the task will be treated as a regular
     *       callback function, which does its processing and optionally returns
     *       HTML output. This is the default behavior which is used when 'type' is
     *       not set.
     *       - 'batch': This indicates that the task function will return a batch
     *       API definition suitable for batch_set(). The installer will then take
     *       care of automatically running the task via batch processing.
     *       - 'form': This indicates that the task function will return a standard
     *       form API definition (and separately define validation and submit
     *       handlers, as appropriate). The installer will then take care of
     *       automatically directing the user through the form submission process.
     *     - 'run'
     *       A constant representing the manner in which the task will be run. This
     *       parameter has three possible values:
     *       - INSTALL_TASK_RUN_IF_NOT_COMPLETED: This indicates that the task will
     *       run once during the installation of the profile. This is the default
     *       behavior which is used when 'run' is not set.
     *       - INSTALL_TASK_SKIP: This indicates that the task will not run during
     *       the current installation page request. It can be used to skip running
     *       an installation task when certain conditions are met, even though the
     *       task may still show on the list of installation tasks presented to the
     *       user.
     *       - INSTALL_TASK_RUN_IF_REACHED: This indicates that the task will run
     *       on each installation page request that reaches it. This is rarely
     *       necessary for an installation profile to use; it is primarily used by
     *       the Drupal installer for bootstrap-related tasks.
     *     - 'function'
     *       Normally this does not need to be set, but it can be used to force the
     *       installer to call a different function when the task is run (rather
     *       than the function whose name is given by the array key). This could be
     *       used, for example, to allow the same function to be called by two
     *       different tasks.
     *
     * @see install_state_defaults()
     * @see batch_set()
     */
    function hook_install_tasks() {
      // Here, we define a variable to allow tasks to indicate that a particular,
      // processor-intensive batch process needs to be triggered later on in the
      // installation.
      $myprofile_needs_batch_processing = variable_get('myprofile_needs_batch_processing', FALSE);
      $tasks = array(
        // This is an example of a task that defines a form which the user who is
        // installing the site will be asked to fill out. To implement this task,
        // your profile would define a function named myprofile_data_import_form()
        // as a normal form API callback function, with associated validation and
        // submit handlers. In the submit handler, in addition to saving whatever
        // other data you have collected from the user, you might also call
        // variable_set('myprofile_needs_batch_processing', TRUE) if the user has
        // entered data which requires that batch processing will need to occur
        // later on.
        'myprofile_data_import_form' => array(
          'display_name' => st('Data import options'),
          'type' => 'form',
        ),
        // Similarly, to implement this task, your profile would define a function
        // named myprofile_settings_form() with associated validation and submit
        // handlers. This form might be used to collect and save additional
        // information from the user that your profile needs. There are no extra
        // steps required for your profile to act as an "installation wizard"; you
        // can simply define as many tasks of type 'form' as you wish to execute,
        // and the forms will be presented to the user, one after another.
        'myprofile_settings_form' => array(
          'display_name' => st('Additional options'),
          'type' => 'form',
        ),
        // This is an example of a task that performs batch operations. To
        // implement this task, your profile would define a function named
        // myprofile_batch_processing() which returns a batch API array definition
        // that the installer will use to execute your batch operations. Due to the
        // 'myprofile_needs_batch_processing' variable used here, this task will be
        // hidden and skipped unless your profile set it to TRUE in one of the
        // previous tasks.
        'myprofile_batch_processing' => array(
          'display_name' => st('Import additional data'),
          'display' => $myprofile_needs_batch_processing,
          'type' => 'batch',
          'run' => $myprofile_needs_batch_processing ? INSTALL_TASK_RUN_IF_NOT_COMPLETED : INSTALL_TASK_SKIP,
        ),
        // This is an example of a task that will not be displayed in the list that
        // the user sees. To implement this task, your profile would define a
        // function named myprofile_final_site_setup(), in which additional,
        // automated site setup operations would be performed. Since this is the
        // last task defined by your profile, you should also use this function to
        // call variable_del('myprofile_needs_batch_processing') and clean up the
        // variable that was used above. If you want the user to pass to the final
        // Drupal installation tasks uninterrupted, return no output from this
        // function. Otherwise, return themed output that the user will see (for
        // example, a confirmation page explaining that your profile's tasks are
        // complete, with a link to reload the current page and therefore pass on
        // to the final Drupal installation tasks when the user is ready to do so).
        'myprofile_final_site_setup' => array(
        ),
      );
      return $tasks;
    }
    
    /**
     * Change the page the user is sent to by drupal_goto().
     *
     * @param &$path
     *   A Drupal path or a full URL.
     * @param &$options
     *   An associative array of additional URL options to pass to url().
     * @param &$http_response_code
     *   The HTTP status code to use for the redirection. See drupal_goto() for more
     *   information.
     */
    function hook_drupal_goto_alter(&$path, &$options, &$http_response_code) {
      // A good addition to misery module.
      $http_response_code = 500;
    }
    
    /**
     * Alter XHTML HEAD tags before they are rendered by drupal_get_html_head().
     *
     * Elements available to be altered are only those added using
     * drupal_add_html_head_link() or drupal_add_html_head(). CSS and JS files
     * are handled using drupal_add_css() and drupal_add_js(), so the head links
     * for those files will not appear in the $head_elements array.
     *
     * @param $head_elements
     *   An array of renderable elements. Generally the values of the #attributes
     *   array will be the most likely target for changes.
     */
    function hook_html_head_alter(&$head_elements) {
      foreach ($head_elements as $key => $element) {
        if (isset($element['#attributes']['rel']) && $element['#attributes']['rel'] == 'canonical') {
          // I want a custom canonical url.
          $head_elements[$key]['#attributes']['href'] = mymodule_canonical_url();
        }
      }
    }
    
    /**
     * Alter the full list of installation tasks.
     *
     * @param $tasks
     *   An array of all available installation tasks, including those provided by
     *   Drupal core. You can modify this array to change or replace any part of
     *   the Drupal installation process that occurs after the installation profile
     *   is selected.
     * @param $install_state
     *   An array of information about the current installation state.
     */
    function hook_install_tasks_alter(&$tasks, $install_state) {
      // Replace the "Choose language" installation task provided by Drupal core
      // with a custom callback function defined by this installation profile.
      $tasks['install_select_locale']['function'] = 'myprofile_locale_selection';
    }
    
    /**
     * Alter MIME type mappings used to determine MIME type from a file extension.
     *
     * This hook is run when file_mimetype_mapping() is called. It is used to
     * allow modules to add to or modify the default mapping from
     * file_default_mimetype_mapping().
     *
     * @param $mapping
     *   An array of mimetypes correlated to the extensions that relate to them.
     *   The array has 'mimetypes' and 'extensions' elements, each of which is an
     *   array.
     *
     * @see file_default_mimetype_mapping()
     */
    function hook_file_mimetype_mapping_alter(&$mapping) {
      // Add new MIME type 'drupal/info'.
      $mapping['mimetypes']['example_info'] = 'drupal/info';
      // Add new extension '.info' and map it to the 'drupal/info' MIME type.
      $mapping['extensions']['info'] = 'example_info';
      // Override existing extension mapping for '.ogg' files.
      $mapping['extensions']['ogg'] = 189;
    }
    
    /**
     * Declares information about actions.
     *
     * Any module can define actions, and then call actions_do() to make those
     * actions happen in response to events. The trigger module provides a user
     * interface for associating actions with module-defined triggers, and it makes
     * sure the core triggers fire off actions when their events happen.
     *
     * An action consists of two or three parts:
     * - an action definition (returned by this hook)
     * - a function which performs the action (which by convention is named
     *   MODULE_description-of-function_action)
     * - an optional form definition function that defines a configuration form
     *   (which has the name of the action function with '_form' appended to it.)
     *
     * The action function takes two to four arguments, which come from the input
     * arguments to actions_do().
     *
     * @return
     *   An associative array of action descriptions. The keys of the array
     *   are the names of the action functions, and each corresponding value
     *   is an associative array with the following key-value pairs:
     *   - 'type': The type of object this action acts upon. Core actions have types
     *     'node', 'user', 'comment', and 'system'.
     *   - 'label': The human-readable name of the action, which should be passed
     *     through the t() function for translation.
     *   - 'configurable': If FALSE, then the action doesn't require any extra
     *     configuration. If TRUE, then your module must define a form function with
     *     the same name as the action function with '_form' appended (e.g., the
     *     form for 'node_assign_owner_action' is 'node_assign_owner_action_form'.)
     *     This function takes $context as its only parameter, and is paired with
     *     the usual _submit function, and possibly a _validate function.
     *   - 'triggers': An array of the events (that is, hooks) that can trigger this
     *     action. For example: array('node_insert', 'user_update'). You can also
     *     declare support for any trigger by returning array('any') for this value.
     *   - 'behavior': (optional) A machine-readable array of behaviors of this
     *     action, used to signal additionally required actions that may need to be
     *     triggered. Currently recognized behaviors by Trigger module:
     *     - 'changes_property': If an action with this behavior is assigned to a
     *       trigger other than a "presave" hook, any save actions also assigned to
     *       this trigger are moved later in the list. If no save action is present,
     *       one will be added.
     *       Modules that are processing actions (like Trigger module) should take
     *       special care for the "presave" hook, in which case a dependent "save"
     *       action should NOT be invoked.
     *
     * @ingroup actions
     */
    function hook_action_info() {
      return array(
        'comment_unpublish_action' => array(
          'type' => 'comment',
          'label' => t('Unpublish comment'),
          'configurable' => FALSE,
          'behavior' => array('changes_property'),
          'triggers' => array('comment_presave', 'comment_insert', 'comment_update'),
        ),
        'comment_unpublish_by_keyword_action' => array(
          'type' => 'comment',
          'label' => t('Unpublish comment containing keyword(s)'),
          'configurable' => TRUE,
          'behavior' => array('changes_property'),
          'triggers' => array('comment_presave', 'comment_insert', 'comment_update'),
        ),
        'comment_save_action' => array(
          'type' => 'comment',
          'label' => t('Save comment'),
          'configurable' => FALSE,
          'triggers' => array('comment_insert', 'comment_update'),
        ),
      );
    }
    
    /**
     * Executes code after an action is deleted.
     *
     * @param $aid
     *   The action ID.
     */
    function hook_actions_delete($aid) {
      db_delete('actions_assignments')
        ->condition('aid', $aid)
        ->execute();
    }
    
    /**
     * Alters the actions declared by another module.
     *
     * Called by actions_list() to allow modules to alter the return values from
     * implementations of hook_action_info().
     *
     * @see trigger_example_action_info_alter()
     */
    function hook_action_info_alter(&$actions) {
      $actions['node_unpublish_action']['label'] = t('Unpublish and remove from public view.');
    }
    
    /**
     * Declare archivers to the system.
     *
     * An archiver is a class that is able to package and unpackage one or more files
     * into a single possibly compressed file.  Common examples of such files are
     * zip files and tar.gz files.  All archiver classes must implement
     * ArchiverInterface.
     *
     * Each entry should be keyed on a unique value, and specify three
     * additional keys:
     * - class: The name of the PHP class for this archiver.
     * - extensions: An array of file extensions that this archiver supports.
     * - weight: This optional key specifies the weight of this archiver.
     *   When mapping file extensions to archivers, the first archiver by
     *   weight found that supports the requested extension will be used.
     *
     * @see hook_archiver_info_alter()
     */
    function hook_archiver_info() {
      return array(
        'tar' => array(
          'class' => 'ArchiverTar',
          'extensions' => array('tar', 'tar.gz', 'tar.bz2'),
        ),
      );
    }
    
    /**
     * Alter archiver information declared by other modules.
     *
     * See hook_archiver_info() for a description of archivers and the archiver
     * information structure.
     *
     * @param $info
     *   Archiver information to alter (return values from hook_archiver_info()).
     */
    function hook_archiver_info_alter(&$info) {
      $info['tar']['extensions'][] = 'tgz';
    }
    
    /**
     * Define additional date types.
     *
     * Next to the 'long', 'medium' and 'short' date types defined in core, any
     * module can define additional types that can be used when displaying dates,
     * by implementing this hook. A date type is basically just a name for a date
     * format.
     *
     * Date types are used in the administration interface: a user can assign
     * date format types defined in hook_date_formats() to date types defined in
     * this hook. Once a format has been assigned by a user, the machine name of a
     * type can be used in the format_date() function to format a date using the
     * chosen formatting.
     *
     * To define a date type in a module and make sure a format has been assigned to
     * it, without requiring a user to visit the administrative interface, use
     * @code variable_set('date_format_' . $type, $format); @endcode
     * where $type is the machine-readable name defined here, and $format is a PHP
     * date format string.
     *
     * To avoid namespace collisions with date types defined by other modules, it is
     * recommended that each date type starts with the module name. A date type
     * can consist of letters, numbers and underscores.
     *
     * @return
     *   An array of date types where the keys are the machine-readable names and
     *   the values are the human-readable labels.
     *
     * @see hook_date_formats()
     * @see format_date()
     */
    function hook_date_format_types() {
      // Define the core date format types.
      return array(
        'long' => t('Long'),
        'medium' => t('Medium'),
        'short' => t('Short'),
      );
    }
    
    /**
     * Modify existing date types.
     *
     * Allows other modules to modify existing date types like 'long'. Called by
     * _system_date_format_types_build(). For instance, A module may use this hook
     * to apply settings across all date types, such as locking all date types so
     * they appear to be provided by the system.
     *
     * @param $types
     *   A list of date types. Each date type is keyed by the machine-readable name
     *   and the values are associative arrays containing:
     *   - is_new: Set to FALSE to override previous settings.
     *   - module: The name of the module that created the date type.
     *   - type: The machine-readable date type name.
     *   - title: The human-readable date type name.
     *   - locked: Specifies that the date type is system-provided.
     */
    function hook_date_format_types_alter(&$types) {
      foreach ($types as $name => $type) {
        $types[$name]['locked'] = 1;
      }
    }
    
    /**
     * Define additional date formats.
     *
     * This hook is used to define the PHP date format strings that can be assigned
     * to date types in the administrative interface. A module can provide date
     * format strings for the core-provided date types ('long', 'medium', and
     * 'short'), or for date types defined in hook_date_format_types() by itself
     * or another module.
     *
     * Since date formats can be locale-specific, you can specify the locales that
     * each date format string applies to. There may be more than one locale for a
     * format. There may also be more than one format for the same locale. For
     * example d/m/Y and Y/m/d work equally well in some locales. You may wish to
     * define some additional date formats that aren't specific to any one locale,
     * for example, "Y m". For these cases, the 'locales' component of the return
     * value should be omitted.
     *
     * Providing a date format here does not normally assign the format to be
     * used with the associated date type -- a user has to choose a format for each
     * date type in the administrative interface. There is one exception: locale
     * initialization chooses a locale-specific format for the three core-provided
     * types (see locale_get_localized_date_format() for details). If your module
     * needs to ensure that a date type it defines has a format associated with it,
     * call @code variable_set('date_format_' . $type, $format); @endcode
     * where $type is the machine-readable name defined in hook_date_format_types(),
     * and $format is a PHP date format string.
     *
     * @return
     *   A list of date formats to offer as choices in the administrative
     *   interface. Each date format is a keyed array consisting of three elements:
     *   - 'type': The date type name that this format can be used with, as
     *     declared in an implementation of hook_date_format_types().
     *   - 'format': A PHP date format string to use when formatting dates. It
     *     can contain any of the formatting options described at
     *     http://php.net/manual/en/function.date.php
     *   - 'locales': (optional) An array of 2 and 5 character locale codes,
     *     defining which locales this format applies to (for example, 'en',
     *     'en-us', etc.). If your date format is not language-specific, leave this
     *     array empty.
     *
     * @see hook_date_format_types()
     */
    function hook_date_formats() {
      return array(
        array(
          'type' => 'mymodule_extra_long',
          'format' => 'l jS F Y H:i:s e',
          'locales' => array('en-ie'),
        ),
        array(
          'type' => 'mymodule_extra_long',
          'format' => 'l jS F Y h:i:sa',
          'locales' => array('en', 'en-us'),
        ),
        array(
          'type' => 'short',
          'format' => 'F Y',
          'locales' => array(),
        ),
      );
    }
    
    /**
     * Alter date formats declared by another module.
     *
     * Called by _system_date_format_types_build() to allow modules to alter the
     * return values from implementations of hook_date_formats().
     */
    function hook_date_formats_alter(&$formats) {
      foreach ($formats as $id => $format) {
        $formats[$id]['locales'][] = 'en-ca';
      }
    }
    
    /**
     * Alters the delivery callback used to send the result of the page callback to the browser.
     *
     * Called by drupal_deliver_page() to allow modules to alter how the
     * page is delivered to the browser.
     *
     * This hook is intended for altering the delivery callback based on
     * information unrelated to the path of the page accessed. For example,
     * it can be used to set the delivery callback based on a HTTP request
     * header (as shown in the code sample). To specify a delivery callback
     * based on path information, use hook_menu() or hook_menu_alter().
     *
     * This hook can also be used as an API function that can be used to explicitly
     * set the delivery callback from some other function. For example, for a module
     * named MODULE:
     * @code
     * function MODULE_page_delivery_callback_alter(&$callback, $set = FALSE) {
     *   static $stored_callback;
     *   if ($set) {
     *     $stored_callback = $callback;
     *   }
     *   elseif (isset($stored_callback)) {
     *     $callback = $stored_callback;
     *   }
     * }
     * function SOMEWHERE_ELSE() {
     *   $desired_delivery_callback = 'foo';
     *   MODULE_page_delivery_callback_alter($desired_delivery_callback, TRUE);
     * }
     * @endcode
     *
     * @param $callback
     *   The name of a function.
     *
     * @see drupal_deliver_page()
     */
    function hook_page_delivery_callback_alter(&$callback) {
      // jQuery sets a HTTP_X_REQUESTED_WITH header of 'XMLHttpRequest'.
      // If a page would normally be delivered as an html page, and it is called
      // from jQuery, deliver it instead as an Ajax response.
      if (isset($_SERVER['HTTP_X_REQUESTED_WITH']) && $_SERVER['HTTP_X_REQUESTED_WITH'] == 'XMLHttpRequest' && $callback == 'drupal_deliver_html_page') {
        $callback = 'ajax_deliver';
      }
    }
    
    /**
     * Alters theme operation links.
     *
     * @param $theme_groups
     *   An associative array containing groups of themes.
     *
     * @see system_themes_page()
     */
    function hook_system_themes_page_alter(&$theme_groups) {
      foreach ($theme_groups as $state => &$group) {
        foreach ($theme_groups[$state] as &$theme) {
          // Add a foo link to each list of theme operations.
          $theme->operations[] = l(t('Foo'), 'admin/appearance/foo', array('query' => array('theme' => $theme->name)));
        }
      }
    }
    
    /**
     * Alters inbound URL requests.
     *
     * @param $path
     *   The path being constructed, which, if a path alias, has been resolved to a
     *   Drupal path by the database, and which also may have been altered by other
     *   modules before this one.
     * @param $original_path
     *   The original path, before being checked for path aliases or altered by any
     *   modules.
     * @param $path_language
     *   The language of the path.
     *
     * @see drupal_get_normal_path()
     */
    function hook_url_inbound_alter(&$path, $original_path, $path_language) {
      // Create the path user/me/edit, which allows a user to edit their account.
      if (preg_match('|^user/me/edit(/.*)?|', $path, $matches)) {
        global $user;
        $path = 'user/' . $user->uid . '/edit' . $matches[1];
      }
    }
    
    /**
     * Alters outbound URLs.
     *
     * @param $path
     *   The outbound path to alter, not adjusted for path aliases yet. It won't be
     *   adjusted for path aliases until all modules are finished altering it, thus
     *   being consistent with hook_url_alter_inbound(), which adjusts for all path
     *   aliases before allowing modules to alter it. This may have been altered by
     *   other modules before this one.
     * @param $options
     *   A set of URL options for the URL so elements such as a fragment or a query
     *   string can be added to the URL.
     * @param $original_path
     *   The original path, before being altered by any modules.
     *
     * @see url()
     */
    function hook_url_outbound_alter(&$path, &$options, $original_path) {
      // Use an external RSS feed rather than the Drupal one.
      if ($path == 'rss.xml') {
        $path = 'http://example.com/rss.xml';
        $options['external'] = TRUE;
      }
    
      // Instead of pointing to user/[uid]/edit, point to user/me/edit.
      if (preg_match('|^user/([0-9]*)/edit(/.*)?|', $path, $matches)) {
        global $user;
        if ($user->uid == $matches[1]) {
          $path = 'user/me/edit' . $matches[2];
        }
      }
    }
    
    /**
     * Alter the username that is displayed for a user.
     *
     * Called by format_username() to allow modules to alter the username that's
     * displayed. Can be used to ensure user privacy in situations where
     * $account->name is too revealing.
     *
     * @param &$name
     *   The string that format_username() will return.
     *
     * @param $account
     *   The account object passed to format_username().
     *
     * @see format_username()
     */
    function hook_username_alter(&$name, $account) {
      // Display the user's uid instead of name.
      if (isset($account->uid)) {
        $name = t('User !uid', array('!uid' => $account->uid));
      }
    }
    
    /**
     * Provide replacement values for placeholder tokens.
     *
     * This hook is invoked when someone calls token_replace(). That function first
     * scans the text for [type:token] patterns, and splits the needed tokens into
     * groups by type. Then hook_tokens() is invoked on each token-type group,
     * allowing your module to respond by providing replacement text for any of
     * the tokens in the group that your module knows how to process.
     *
     * A module implementing this hook should also implement hook_token_info() in
     * order to list its available tokens on editing screens.
     *
     * @param $type
     *   The machine-readable name of the type (group) of token being replaced, such
     *   as 'node', 'user', or another type defined by a hook_token_info()
     *   implementation.
     * @param $tokens
     *   An array of tokens to be replaced. The keys are the machine-readable token
     *   names, and the values are the raw [type:token] strings that appeared in the
     *   original text.
     * @param $data
     *   (optional) An associative array of data objects to be used when generating
     *   replacement values, as supplied in the $data parameter to token_replace().
     * @param $options
     *   (optional) An associative array of options for token replacement; see
     *   token_replace() for possible values.
     *
     * @return
     *   An associative array of replacement values, keyed by the raw [type:token]
     *   strings from the original text.
     *
     * @see hook_token_info()
     * @see hook_tokens_alter()
     */
    function hook_tokens($type, $tokens, array $data = array(), array $options = array()) {
      $url_options = array('absolute' => TRUE);
      if (isset($options['language'])) {
        $url_options['language'] = $options['language'];
        $language_code = $options['language']->language;
      }
      else {
        $language_code = NULL;
      }
      $sanitize = !empty($options['sanitize']);
    
      $replacements = array();
    
      if ($type == 'node' && !empty($data['node'])) {
        $node = $data['node'];
    
        foreach ($tokens as $name => $original) {
          switch ($name) {
            // Simple key values on the node.
            case 'nid':
              $replacements[$original] = $node->nid;
              break;
    
            case 'title':
              $replacements[$original] = $sanitize ? check_plain($node->title) : $node->title;
              break;
    
            case 'edit-url':
              $replacements[$original] = url('node/' . $node->nid . '/edit', $url_options);
              break;
    
            // Default values for the chained tokens handled below.
            case 'author':
              $name = ($node->uid == 0) ? variable_get('anonymous', t('Anonymous')) : $node->name;
              $replacements[$original] = $sanitize ? filter_xss($name) : $name;
              break;
    
            case 'created':
              $replacements[$original] = format_date($node->created, 'medium', '', NULL, $language_code);
              break;
          }
        }
    
        if ($author_tokens = token_find_with_prefix($tokens, 'author')) {
          $author = user_load($node->uid);
          $replacements += token_generate('user', $author_tokens, array('user' => $author), $options);
        }
    
        if ($created_tokens = token_find_with_prefix($tokens, 'created')) {
          $replacements += token_generate('date', $created_tokens, array('date' => $node->created), $options);
        }
      }
    
      return $replacements;
    }
    
    /**
     * Alter replacement values for placeholder tokens.
     *
     * @param $replacements
     *   An associative array of replacements returned by hook_tokens().
     * @param $context
     *   The context in which hook_tokens() was called. An associative array with
     *   the following keys, which have the same meaning as the corresponding
     *   parameters of hook_tokens():
     *   - 'type'
     *   - 'tokens'
     *   - 'data'
     *   - 'options'
     *
     * @see hook_tokens()
     */
    function hook_tokens_alter(array &$replacements, array $context) {
      $options = $context['options'];
    
      if (isset($options['language'])) {
        $url_options['language'] = $options['language'];
        $language_code = $options['language']->language;
      }
      else {
        $language_code = NULL;
      }
      $sanitize = !empty($options['sanitize']);
    
      if ($context['type'] == 'node' && !empty($context['data']['node'])) {
        $node = $context['data']['node'];
    
        // Alter the [node:title] token, and replace it with the rendered content
        // of a field (field_title).
        if (isset($context['tokens']['title'])) {
          $title = field_view_field('node', $node, 'field_title', 'default', $language_code);
          $replacements[$context['tokens']['title']] = drupal_render($title);
        }
      }
    }
    
    /**
     * Provide information about available placeholder tokens and token types.
     *
     * Tokens are placeholders that can be put into text by using the syntax
     * [type:token], where type is the machine-readable name of a token type, and
     * token is the machine-readable name of a token within this group. This hook
     * provides a list of types and tokens to be displayed on text editing screens,
     * so that people editing text can see what their token options are.
     *
     * The actual token replacement is done by token_replace(), which invokes
     * hook_tokens(). Your module will need to implement that hook in order to
     * generate token replacements from the tokens defined here.
     *
     * @return
     *   An associative array of available tokens and token types. The outer array
     *   has two components:
     *   - types: An associative array of token types (groups). Each token type is
     *     an associative array with the following components:
     *     - name: The translated human-readable short name of the token type.
     *     - description: A translated longer description of the token type.
     *     - needs-data: The type of data that must be provided to token_replace()
     *       in the $data argument (i.e., the key name in $data) in order for tokens
     *       of this type to be used in the $text being processed. For instance, if
     *       the token needs a node object, 'needs-data' should be 'node', and to
     *       use this token in token_replace(), the caller needs to supply a node
     *       object as $data['node']. Some token data can also be supplied
     *       indirectly; for instance, a node object in $data supplies a user object
     *       (the author of the node), allowing user tokens to be used when only
     *       a node data object is supplied.
     *   - tokens: An associative array of tokens. The outer array is keyed by the
     *     group name (the same key as in the types array). Within each group of
     *     tokens, each token item is keyed by the machine name of the token, and
     *     each token item has the following components:
     *     - name: The translated human-readable short name of the token.
     *     - description: A translated longer description of the token.
     *     - type (optional): A 'needs-data' data type supplied by this token, which
     *       should match a 'needs-data' value from another token type. For example,
     *       the node author token provides a user object, which can then be used
     *       for token replacement data in token_replace() without having to supply
     *       a separate user object.
     *
     * @see hook_token_info_alter()
     * @see hook_tokens()
     */
    function hook_token_info() {
      $type = array(
        'name' => t('Nodes'),
        'description' => t('Tokens related to individual nodes.'),
        'needs-data' => 'node',
      );
    
      // Core tokens for nodes.
      $node['nid'] = array(
        'name' => t("Node ID"),
        'description' => t("The unique ID of the node."),
      );
      $node['title'] = array(
        'name' => t("Title"),
        'description' => t("The title of the node."),
      );
      $node['edit-url'] = array(
        'name' => t("Edit URL"),
        'description' => t("The URL of the node's edit page."),
      );
    
      // Chained tokens for nodes.
      $node['created'] = array(
        'name' => t("Date created"),
        'description' => t("The date the node was posted."),
        'type' => 'date',
      );
      $node['author'] = array(
        'name' => t("Author"),
        'description' => t("The author of the node."),
        'type' => 'user',
      );
    
      return array(
        'types' => array('node' => $type),
        'tokens' => array('node' => $node),
      );
    }
    
    /**
     * Alter the metadata about available placeholder tokens and token types.
     *
     * @param $data
     *   The associative array of token definitions from hook_token_info().
     *
     * @see hook_token_info()
     */
    function hook_token_info_alter(&$data) {
      // Modify description of node tokens for our site.
      $data['tokens']['node']['nid'] = array(
        'name' => t("Node ID"),
        'description' => t("The unique ID of the article."),
      );
      $data['tokens']['node']['title'] = array(
        'name' => t("Title"),
        'description' => t("The title of the article."),
      );
    
      // Chained tokens for nodes.
      $data['tokens']['node']['created'] = array(
        'name' => t("Date created"),
        'description' => t("The date the article was posted."),
        'type' => 'date',
      );
    }
    
    /**
     * Alter batch information before a batch is processed.
     *
     * Called by batch_process() to allow modules to alter a batch before it is
     * processed.
     *
     * @param $batch
     *   The associative array of batch information. See batch_set() for details on
     *   what this could contain.
     *
     * @see batch_set()
     * @see batch_process()
     *
     * @ingroup batch
     */
    function hook_batch_alter(&$batch) {
      // If the current page request is inside the overlay, add ?render=overlay to
      // the success callback URL, so that it appears correctly within the overlay.
      if (overlay_get_mode() == 'child') {
        if (isset($batch['url_options']['query'])) {
          $batch['url_options']['query']['render'] = 'overlay';
        }
        else {
          $batch['url_options']['query'] = array('render' => 'overlay');
        }
      }
    }
    
    /**
     * Provide information on Updaters (classes that can update Drupal).
     *
     * An Updater is a class that knows how to update various parts of the Drupal
     * file system, for example to update modules that have newer releases, or to
     * install a new theme.
     *
     * @return
     *   An associative array of information about the updater(s) being provided.
     *   This array is keyed by a unique identifier for each updater, and the
     *   values are subarrays that can contain the following keys:
     *   - class: The name of the PHP class which implements this updater.
     *   - name: Human-readable name of this updater.
     *   - weight: Controls what order the Updater classes are consulted to decide
     *     which one should handle a given task. When an update task is being run,
     *     the system will loop through all the Updater classes defined in this
     *     registry in weight order and let each class respond to the task and
     *     decide if each Updater wants to handle the task. In general, this
     *     doesn't matter, but if you need to override an existing Updater, make
     *     sure your Updater has a lighter weight so that it comes first.
     *
     * @see drupal_get_updaters()
     * @see hook_updater_info_alter()
     */
    function hook_updater_info() {
      return array(
        'module' => array(
          'class' => 'ModuleUpdater',
          'name' => t('Update modules'),
          'weight' => 0,
        ),
        'theme' => array(
          'class' => 'ThemeUpdater',
          'name' => t('Update themes'),
          'weight' => 0,
        ),
      );
    }
    
    /**
     * Alter the Updater information array.
     *
     * An Updater is a class that knows how to update various parts of the Drupal
     * file system, for example to update modules that have newer releases, or to
     * install a new theme.
     *
     * @param array $updaters
     *   Associative array of updaters as defined through hook_updater_info().
     *   Alter this array directly.
     *
     * @see drupal_get_updaters()
     * @see hook_updater_info()
     */
    function hook_updater_info_alter(&$updaters) {
      // Adjust weight so that the theme Updater gets a chance to handle a given
      // update task before module updaters.
      $updaters['theme']['weight'] = -1;
    }
    
    /**
     * Alter the default country list.
     *
     * @param $countries
     *   The associative array of countries keyed by ISO 3166-1 country code.
     *
     * @see country_get_list()
     * @see _country_get_predefined_list()
     */
    function hook_countries_alter(&$countries) {
      // Elbonia is now independent, so add it to the country list.
      $countries['EB'] = 'Elbonia';
    }
    
    /**
     * Control site status before menu dispatching.
     *
     * The hook is called after checking whether the site is offline but before
     * the current router item is retrieved and executed by
     * menu_execute_active_handler(). If the site is in offline mode,
     * $menu_site_status is set to MENU_SITE_OFFLINE.
     *
     * @param $menu_site_status
     *   Supported values are MENU_SITE_OFFLINE, MENU_ACCESS_DENIED,
     *   MENU_NOT_FOUND and MENU_SITE_ONLINE. Any other value than
     *   MENU_SITE_ONLINE will skip the default menu handling system and be passed
     *   for delivery to drupal_deliver_page() with a NULL
     *   $default_delivery_callback.
     * @param $path
     *   Contains the system path that is going to be loaded. This is read only,
     *   use hook_url_inbound_alter() to change the path.
     */
    function hook_menu_site_status_alter(&$menu_site_status, $path) {
      // Allow access to my_module/authentication even if site is in offline mode.
      if ($menu_site_status == MENU_SITE_OFFLINE && user_is_anonymous() && $path == 'my_module/authentication') {
        $menu_site_status = MENU_SITE_ONLINE;
      }
    }
    
    /**
     * Register information about FileTransfer classes provided by a module.
     *
     * The FileTransfer class allows transfering files over a specific type of
     * connection. Core provides classes for FTP and SSH. Contributed modules are
     * free to extend the FileTransfer base class to add other connection types,
     * and if these classes are registered via hook_filetransfer_info(), those
     * connection types will be available to site administrators using the Update
     * manager when they are redirected to the authorize.php script to authorize
     * the file operations.
     *
     * @return array
     *   Nested array of information about FileTransfer classes. Each key is a
     *   FileTransfer type (not human readable, used for form elements and
     *   variable names, etc), and the values are subarrays that define properties
     *   of that type. The keys in each subarray are:
     *   - 'title': Required. The human-readable name of the connection type.
     *   - 'class': Required. The name of the FileTransfer class. The constructor
     *     will always be passed the full path to the root of the site that should
     *     be used to restrict where file transfer operations can occur (the $jail)
     *     and an array of settings values returned by the settings form.
     *   - 'file': Required. The include file containing the FileTransfer class.
     *     This should be a separate .inc file, not just the .module file, so that
     *     the minimum possible code is loaded when authorize.php is running.
     *   - 'file path': Optional. The directory (relative to the Drupal root)
     *     where the include file lives. If not defined, defaults to the base
     *     directory of the module implementing the hook.
     *   - 'weight': Optional. Integer weight used for sorting connection types on
     *     the authorize.php form.
     *
     * @see FileTransfer
     * @see authorize.php
     * @see hook_filetransfer_info_alter()
     * @see drupal_get_filetransfer_info()
     */
    function hook_filetransfer_info() {
      $info['sftp'] = array(
        'title' => t('SFTP (Secure FTP)'),
        'file' => 'sftp.filetransfer.inc',
        'class' => 'FileTransferSFTP',
        'weight' => 10,
      );
      return $info;
    }
    
    /**
     * Alter the FileTransfer class registry.
     *
     * @param array $filetransfer_info
     *   Reference to a nested array containing information about the FileTransfer
     *   class registry.
     *
     * @see hook_filetransfer_info()
     */
    function hook_filetransfer_info_alter(&$filetransfer_info) {
      if (variable_get('paranoia', FALSE)) {
        // Remove the FTP option entirely.
        unset($filetransfer_info['ftp']);
        // Make sure the SSH option is listed first.
        $filetransfer_info['ssh']['weight'] = -10;
      }
    }
    
    /**
     * @} End of "addtogroup hooks".
     */