<?php

// $Id: block.module,v 1.299.2.3 2008/06/24 14:40:08 goba Exp $

/**

 * @file

 * Controls the boxes that are displayed around the main content.

 */

/**

 * Denotes that a block is not enabled in any region and should not

 * be shown.

 */

define('BLOCK_REGION_NONE', -1);

/**

 * Constants defining cache granularity for blocks.

 *

 * Modules specify the caching patterns for their blocks using binary

 * combinations of these constants in their hook_block(op 'list'):

 *   $block[delta]['cache'] = BLOCK_CACHE_PER_ROLE | BLOCK_CACHE_PER_PAGE;

 * BLOCK_CACHE_PER_ROLE is used as a default when no caching pattern is

 * specified.

 *

 * The block cache is cleared in cache_clear_all(), and uses the same clearing

 * policy than page cache (node, comment, user, taxonomy added or updated...).

 * Blocks requiring more fine-grained clearing might consider disabling the

 * built-in block cache (BLOCK_NO_CACHE) and roll their own.

 *

 * Note that user 1 is excluded from block caching.

 */

/**

 * The block should not get cached. This setting should be used:

 * - for simple blocks (notably those that do not perform any db query),

 * where querying the db cache would be more expensive than directly generating

 * the content.

 * - for blocks that change too frequently.

 */

define('BLOCK_NO_CACHE', -1);

/**

 * The block can change depending on the roles the user viewing the page belongs to.

 * This is the default setting, used when the block does not specify anything.

 */

define('BLOCK_CACHE_PER_ROLE', 0x0001);

/**

 * The block can change depending on the user viewing the page.

 * This setting can be resource-consuming for sites with large number of users,

 * and thus should only be used when BLOCK_CACHE_PER_ROLE is not sufficient.

 */

define('BLOCK_CACHE_PER_USER', 0x0002);

/**

 * The block can change depending on the page being viewed.

 */

define('BLOCK_CACHE_PER_PAGE', 0x0004);

/**

 * The block is the same for every user on every page where it is visible.

 */

define('BLOCK_CACHE_GLOBAL', 0x0008);

/**

 * Implementation of hook_help().

 */

function block_help($path, $arg) {

  switch ($path) {

    case 'admin/help#block':

      $output = '<p>'. t('Blocks are boxes of content rendered into an area, or region, of a web page. The default theme Garland, for example, implements the regions "left sidebar", "right sidebar", "content", "header", and "footer", and a block may appear in any one of these areas. The <a href="@blocks">blocks administration page</a> provides a drag-and-drop interface for assigning a block to a region, and for controlling the order of blocks within regions.', array('@blocks' => url('admin/build/block'))) .'</p>';

      $output .= '<p>'. t('Although blocks are usually generated automatically by modules (like the <em>User login</em> block, for example), administrators can also define custom blocks. Custom blocks have a title, description, and body. The body of the block can be as long as necessary, and can contain content supported by any available <a href="@input-format">input format</a>.', array('@input-format' => url('admin/settings/filters'))) .'</p>';

      $output .= '<p>'. t('When working with blocks, remember that:') .'</p>';

      $output .= '<ul><li>'. t('since not all themes implement the same regions, or display regions in the same way, blocks are positioned on a per-theme basis.') .'</li>';

      $output .= '<li>'. t('disabled blocks, or blocks not in a region, are never shown.') .'</li>';

      $output .= '<li>'. t('when throttle module is enabled, throttled blocks (blocks with the <em>Throttle</em> checkbox selected) are hidden during high server loads.') .'</li>';

      $output .= '<li>'. t('blocks can be configured to be visible only on certain pages.') .'</li>';

      $output .= '<li>'. t('blocks can be configured to be visible only when specific conditions are true.') .'</li>';

      $output .= '<li>'. t('blocks can be configured to be visible only for certain user roles.') .'</li>';

      $output .= '<li>'. t('when allowed by an administrator, specific blocks may be enabled or disabled on a per-user basis using the <em>My account</em> page.') .'</li>';

      $output .= '<li>'. t('some dynamic blocks, such as those generated by modules, will be displayed only on certain pages.') .'</li></ul>';

      $output .= '<p>'. t('For more information, see the online handbook entry for <a href="@block">Block module</a>.', array('@block' => 'http://drupal.org/handbook/modules/block/')) .'</p>';

      return $output;

    case 'admin/build/block':

      $throttle = module_exists('throttle');

      $output = '<p>'. t('This page provides a drag-and-drop interface for assigning a block to a region, and for controlling the order of blocks within regions. To change the region or order of a block, grab a drag-and-drop handle under the <em>Block</em> column and drag the block to a new location in the list. (Grab a handle by clicking and holding the mouse while hovering over a handle icon.) Since not all themes implement the same regions, or display regions in the same way, blocks are positioned on a per-theme basis. Remember that your changes will not be saved until you click the <em>Save blocks</em> button at the bottom of the page.') .'</p>';

      if ($throttle) {

        $output .= '<p>'. t('To reduce CPU usage, database traffic or bandwidth, blocks may be automatically disabled during high server loads by selecting their <em>Throttle</em> checkbox. Adjust throttle thresholds on the <a href="@throttleconfig">throttle configuration page</a>.', array('@throttleconfig' => url('admin/settings/throttle'))) .'</p>';

      }

      $output .= '<p>'. t('Click the <em>configure</em> link next to each block to configure its specific title and visibility settings. Use the <a href="@add-block">add block page</a> to create a custom block.', array('@add-block' => url('admin/build/block/add'))) .'</p>';

      return $output;

    case 'admin/build/block/add':

      return '<p>'. t('Use this page to create a new custom block. New blocks are disabled by default, and must be moved to a region on the <a href="@blocks">blocks administration page</a> to be visible.', array('@blocks' => url('admin/build/block'))) .'</p>';

  }

}

/**

 * Implementation of hook_theme()

 */

function block_theme() {

  return array(

    'block_admin_display_form' => array(

      'template' => 'block-admin-display-form',

      'file' => 'block.admin.inc',

      'arguments' => array('form' => NULL),

    ),

  );

}

/**

 * Implementation of hook_perm().

 */

function block_perm() {

  return array('administer blocks', 'use PHP for block visibility');

}

/**

 * Implementation of hook_menu().

 */

function block_menu() {

  $items['admin/build/block'] = array(

    'title' => 'Blocks',

    'description' => 'Configure what block content appears in your site\'s sidebars and other regions.',

    'page callback' => 'block_admin_display',

    'access arguments' => array('administer blocks'),

    'file' => 'block.admin.inc',

  );

  $items['admin/build/block/list'] = array(

    'title' => 'List',

    'type' => MENU_DEFAULT_LOCAL_TASK,

    'weight' => -10,

  );

  $items['admin/build/block/list/js'] = array(

    'title' => 'JavaScript List Form',

    'page callback' => 'block_admin_display_js',

    'access arguments' => array('administer blocks'),

    'type' => MENU_CALLBACK,

    'file' => 'block.admin.inc',

  );

  $items['admin/build/block/configure'] = array(

    'title' => 'Configure block',

    'page callback' => 'drupal_get_form',

    'page arguments' => array('block_admin_configure'),

    'access arguments' => array('administer blocks'),

    'type' => MENU_CALLBACK,

    'file' => 'block.admin.inc',

  );

  $items['admin/build/block/delete'] = array(

    'title' => 'Delete block',

    'page callback' => 'drupal_get_form',

    'page arguments' => array('block_box_delete'),

    'access arguments' => array('administer blocks'),

    'type' => MENU_CALLBACK,

    'file' => 'block.admin.inc',

  );

  $items['admin/build/block/add'] = array(

    'title' => 'Add block',

    'page callback' => 'drupal_get_form',

    'page arguments' => array('block_add_block_form'),

    'access arguments' => array('administer blocks'),

    'type' => MENU_LOCAL_TASK,

    'file' => 'block.admin.inc',

  );

  $default = variable_get('theme_default', 'garland');

  foreach (list_themes() as $key => $theme) {

    $items['admin/build/block/list/'. $key] = array(

      'title' => check_plain($theme->info['name']),

      'page arguments' => array($key),

      'type' => $key == $default ? MENU_DEFAULT_LOCAL_TASK : MENU_LOCAL_TASK,

      'weight' => $key == $default ? -10 : 0,

      'file' => 'block.admin.inc',

      'access callback' => '_block_themes_access',

      'access arguments' => array($theme),

    );

  }

  return $items;

}

/**

 * Menu item access callback - only admin or enabled themes can be accessed

 */

function _block_themes_access($theme) {

  return user_access('administer blocks') && ($theme->status || $theme->name == variable_get('admin_theme', '0'));

}

/**

 * Implementation of hook_block().

 *

 * Generates the administrator-defined blocks for display.

 */

function block_block($op = 'list', $delta = 0, $edit = array()) {

  switch ($op) {

    case 'list':

      $blocks = array();

      $result = db_query('SELECT bid, info FROM {boxes} ORDER BY info');

      while ($block = db_fetch_object($result)) {

        $blocks[$block->bid]['info'] = $block->info;

        // Not worth caching.

        $blocks[$block->bid]['cache'] = BLOCK_NO_CACHE;

      }

      return $blocks;

    case 'configure':

      $box = array('format' => FILTER_FORMAT_DEFAULT);

      if ($delta) {

        $box = block_box_get($delta);

      }

      if (filter_access($box['format'])) {

        return block_box_form($box);

      }

      break;

    case 'save':

      block_box_save($edit, $delta);

      break;

    case 'view':

      $block = db_fetch_object(db_query('SELECT body, format FROM {boxes} WHERE bid = %d', $delta));

      $data['content'] = check_markup($block->body, $block->format, FALSE);

      return $data;

  }

}

/**

 * Update the 'blocks' DB table with the blocks currently exported by modules.

 *

 * @return

 *   Blocks currently exported by modules.

 */

function _block_rehash() {

  global $theme_key;

  init_theme();

  $result = db_query("SELECT * FROM {blocks} WHERE theme = '%s'", $theme_key);

  $old_blocks = array();

  while ($old_block = db_fetch_array($result)) {

    $old_blocks[$old_block['module']][$old_block['delta']] = $old_block;

  }

  $blocks = array();

  // Valid region names for the theme.

  $regions = system_region_list($theme_key);

  foreach (module_list() as $module) {

    $module_blocks = module_invoke($module, 'block', 'list');

    if ($module_blocks) {

      foreach ($module_blocks as $delta => $block) {

        if (empty($old_blocks[$module][$delta])) {

          // If it's a new block, add identifiers.

          $block['module'] = $module;

          $block['delta']  = $delta;

          $block['theme']  = $theme_key;

          if (!isset($block['pages'])) {

            // {block}.pages is type 'text', so it cannot have a

            // default value, and not null, so we need to provide

            // value if the module did not.

            $block['pages']  = '';

          }

          // Add defaults and save it into the database.

          drupal_write_record('blocks', $block);

          // Set region to none if not enabled.

          $block['region'] = $block['status'] ? $block['region'] : BLOCK_REGION_NONE;

          // Add to the list of blocks we return.

          $blocks[] = $block;

        }

        else {

          // If it's an existing block, database settings should overwrite

          // the code. But aside from 'info' everything that's definable in

          // code is stored in the database and we do not store 'info', so we

          // do not need to update the database here.

          // Add 'info' to this block.

          $old_blocks[$module][$delta]['info'] = $block['info'];

          // If the region name does not exist, disable the block and assign it to none.

          if (!empty($old_blocks[$module][$delta]['region']) && !isset($regions[$old_blocks[$module][$delta]['region']])) {

            drupal_set_message(t('The block %info was assigned to the invalid region %region and has been disabled.', array('%info' => $old_blocks[$module][$delta]['info'], '%region' => $old_blocks[$module][$delta]['region'])), 'warning');

            $old_blocks[$module][$delta]['status'] = 0;

            $old_blocks[$module][$delta]['region'] = BLOCK_REGION_NONE;

          }

          else {

            $old_blocks[$module][$delta]['region'] = $old_blocks[$module][$delta]['status'] ? $old_blocks[$module][$delta]['region'] : BLOCK_REGION_NONE;

          }

          // Add this block to the list of blocks we return.

          $blocks[] = $old_blocks[$module][$delta];

          // Remove this block from the list of blocks to be deleted.

          unset($old_blocks[$module][$delta]);

        }

      }

    }

  }

  // Remove blocks that are no longer defined by the code from the database.

  foreach ($old_blocks as $module => $old_module_blocks) {

    foreach ($old_module_blocks as $delta => $block) {

      db_query("DELETE FROM {blocks} WHERE module = '%s' AND delta = '%s' AND theme = '%s'", $module, $delta, $theme_key);

    }

  }

  return $blocks;

}

function block_box_get($bid) {

  return db_fetch_array(db_query("SELECT * FROM {boxes} WHERE bid = %d", $bid));

}

/**

 * Define the custom block form.

 */

function block_box_form($edit = array()) {

  $edit += array(

    'info' => '',

    'body' => '',

  );

  $form['info'] = array(

    '#type' => 'textfield',

    '#title' => t('Block description'),

    '#default_value' => $edit['info'],

    '#maxlength' => 64,

    '#description' => t('A brief description of your block. Used on the <a href="@overview">block overview page</a>.', array('@overview' => url('admin/build/block'))),

    '#required' => TRUE,

    '#weight' => -19,

  );

  $form['body_field']['#weight'] = -17;

  $form['body_field']['body'] = array(

    '#type' => 'textarea',

    '#title' => t('Block body'),

    '#default_value' => $edit['body'],

    '#rows' => 15,

    '#description' => t('The content of the block as shown to the user.'),

    '#weight' => -17,

  );

  if (!isset($edit['format'])) {

    $edit['format'] = FILTER_FORMAT_DEFAULT;

  }

  $form['body_field']['format'] = filter_form($edit['format'], -16);

  return $form;

}

function block_box_save($edit, $delta) {

  if (!filter_access($edit['format'])) {

    $edit['format'] = FILTER_FORMAT_DEFAULT;

  }

  db_query("UPDATE {boxes} SET body = '%s', info = '%s', format = %d WHERE bid = %d", $edit['body'], $edit['info'], $edit['format'], $delta);

  return TRUE;

}

/**

 * Implementation of hook_user().

 *

 * Allow users to decide which custom blocks to display when they visit

 * the site.

 */

function block_user($type, $edit, &$account, $category = NULL) {

  switch ($type) {

    case 'form':

      if ($category == 'account') {

        $rids = array_keys($account->roles);

        $result = db_query("SELECT DISTINCT b.* FROM {blocks} b LEFT JOIN {blocks_roles} r ON b.module = r.module AND b.delta = r.delta WHERE b.status = 1 AND b.custom != 0 AND (r.rid IN (". db_placeholders($rids) .") OR r.rid IS NULL) ORDER BY b.weight, b.module", $rids);

        $form['block'] = array('#type' => 'fieldset', '#title' => t('Block configuration'), '#weight' => 3, '#collapsible' => TRUE, '#tree' => TRUE);

        while ($block = db_fetch_object($result)) {

          $data = module_invoke($block->module, 'block', 'list');

          if ($data[$block->delta]['info']) {

            $return = TRUE;

            $form['block'][$block->module][$block->delta] = array('#type' => 'checkbox', '#title' => check_plain($data[$block->delta]['info']), '#default_value' => isset($account->block[$block->module][$block->delta]) ? $account->block[$block->module][$block->delta] : ($block->custom == 1));

          }

        }

        if (!empty($return)) {

          return $form;

        }

      }

      break;

    case 'validate':

      if (empty($edit['block'])) {

        $edit['block'] = array();

      }

      return $edit;

  }

}

/**

 * Return all blocks in the specified region for the current user.

 *

 * @param $region

 *   The name of a region.

 *

 * @return

 *   An array of block objects, indexed with <i>module</i>_<i>delta</i>.

 *   If you are displaying your blocks in one or two sidebars, you may check

 *   whether this array is empty to see how many columns are going to be

 *   displayed.

 *

 * @todo

 *   Now that the blocks table has a primary key, we should use that as the

 *   array key instead of <i>module</i>_<i>delta</i>.

 */

function block_list($region) {

  global $user, $theme_key;

  static $blocks = array();

  if (!count($blocks)) {

    $rids = array_keys($user->roles);

    $result = db_query(db_rewrite_sql("SELECT DISTINCT b.* FROM {blocks} b LEFT JOIN {blocks_roles} r ON b.module = r.module AND b.delta = r.delta WHERE b.theme = '%s' AND b.status = 1 AND (r.rid IN (". db_placeholders($rids) .") OR r.rid IS NULL) ORDER BY b.region, b.weight, b.module", 'b', 'bid'), array_merge(array($theme_key), $rids));

    while ($block = db_fetch_object($result)) {

      if (!isset($blocks[$block->region])) {

        $blocks[$block->region] = array();

      }

      // Use the user's block visibility setting, if necessary

      if ($block->custom != 0) {

        if ($user->uid && isset($user->block[$block->module][$block->delta])) {

          $enabled = $user->block[$block->module][$block->delta];

        }

        else {

          $enabled = ($block->custom == 1);

        }

      }

      else {

        $enabled = TRUE;

      }

      // Match path if necessary

      if ($block->pages) {

        if ($block->visibility < 2) {

          $path = drupal_get_path_alias($_GET['q']);

          // Compare with the internal and path alias (if any).

          $page_match = drupal_match_path($path, $block->pages);

          if ($path != $_GET['q']) {

            $page_match = $page_match || drupal_match_path($_GET['q'], $block->pages);

          }

          // When $block->visibility has a value of 0, the block is displayed on

          // all pages except those listed in $block->pages. When set to 1, it

          // is displayed only on those pages listed in $block->pages.

          $page_match = !($block->visibility xor $page_match);

        }

        else {

          $page_match = drupal_eval($block->pages);

        }

      }

      else {

        $page_match = TRUE;

      }

      $block->enabled = $enabled;

      $block->page_match = $page_match;

      $blocks[$block->region]["{$block->module}_{$block->delta}"] = $block;

    }

  }

  // Create an empty array if there were no entries

  if (!isset($blocks[$region])) {

    $blocks[$region] = array();

  }

  foreach ($blocks[$region] as $key => $block) {

    // Render the block content if it has not been created already.

    if (!isset($block->content)) {

      // Erase the block from the static array - we'll put it back if it has content.

      unset($blocks[$region][$key]);

      if ($block->enabled && $block->page_match) {

        // Check the current throttle status and see if block should be displayed

        // based on server load.

        if (!($block->throttle && (module_invoke('throttle', 'status') > 0))) {

          // Try fetching the block from cache. Block caching is not compatible with

          // node_access modules. We also preserve the submission of forms in blocks,

          // by fetching from cache only if the request method is 'GET'.

          if (!count(module_implements('node_grants')) && $_SERVER['REQUEST_METHOD'] == 'GET' && ($cid = _block_get_cache_id($block)) && ($cache = cache_get($cid, 'cache_block'))) {

            $array = $cache->data;

          }

          else {

            $array = module_invoke($block->module, 'block', 'view', $block->delta);

            if (isset($cid)) {

              cache_set($cid, $array, 'cache_block', CACHE_TEMPORARY);

            }

          }

          if (isset($array) && is_array($array)) {

            foreach ($array as $k => $v) {

              $block->$k = $v;

            }

          }

        }

        if (isset($block->content) && $block->content) {

          // Override default block title if a custom display title is present.

          if ($block->title) {

            // Check plain here to allow module generated titles to keep any markup.

            $block->subject = $block->title == '<none>' ? '' : check_plain($block->title);

          }

          if (!isset($block->subject)) {

            $block->subject = '';

          }

          $blocks[$block->region]["{$block->module}_{$block->delta}"] = $block;

        }

      }

    }

  }

  return $blocks[$region];

}

/**

 * Assemble the cache_id to use for a given block.

 *

 * The cache_id string reflects the viewing context for the current block

 * instance, obtained by concatenating the relevant context information

 * (user, page, ...) according to the block's cache settings (BLOCK_CACHE_*

 * constants). Two block instances can use the same cached content when

 * they share the same cache_id.

 *

 * Theme and language contexts are automatically differenciated.

 *

 * @param $block

 * @return

 *   The string used as cache_id for the block.

 */

function _block_get_cache_id($block) {

  global $theme, $base_root, $user;

  // User 1 being out of the regular 'roles define permissions' schema,

  // it brings too many chances of having unwanted output get in the cache

  // and later be served to other users. We therefore exclude user 1 from

  // block caching.

  if (variable_get('block_cache', 0) && $block->cache != BLOCK_NO_CACHE && $user->uid != 1) {

    $cid_parts = array();

    // Start with common sub-patterns: block identification, theme, language.

    $cid_parts[] = $block->module;

    $cid_parts[] = $block->delta;