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Drupal example source code file (block.module)

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

PHP - Drupal tags/keywords

array, block, blocks, foreach, function, if, isset, key, page, php, region, return, theme, variable

The block.module Drupal example source code

<?php
// $Id: block.module,v 1.435 2010/11/23 16:12:15 webchick Exp $

/**
 * @file
 * Controls the visual building blocks a page is constructed with.
 */

/**
 * Denotes that a block is not enabled in any region and should not be shown.
 */
define('BLOCK_REGION_NONE', -1);

/**
 * Users cannot control whether or not they see this block.
 */
define('BLOCK_CUSTOM_FIXED', 0);

/**
 *  Show this block by default, but let individual users hide it.
 */
define('BLOCK_CUSTOM_ENABLED', 1);

/**
 * Hide this block by default but let individual users show it.
 */
define('BLOCK_CUSTOM_DISABLED', 2);

/**
 * Show this block on every page except the listed pages.
 */
define('BLOCK_VISIBILITY_NOTLISTED', 0);

/**
 * Show this block on only the listed pages.
 */
define('BLOCK_VISIBILITY_LISTED', 1);

/**
 * Show this block if the associated PHP code returns TRUE.
 */
define('BLOCK_VISIBILITY_PHP', 2);

/**
 * Implements hook_help().
 */
function block_help($path, $arg) {
  switch ($path) {
    case 'admin/help#block':
      $output = '';
      $output .= '<h3>' . t('About') . '</h3>';
      $output .= '<p>' . t('The Block module allows you to create boxes of content, which are rendered into an area, or region, of one or more pages of a website. The core Seven administration theme, for example, implements the regions "Content", "Help", "Dashboard main", and "Dashboard sidebar", and a block may appear in any one of these regions. 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. For more information, see the online handbook entry for <a href="@block">Block module</a>.', array('@block' => 'http://drupal.org/handbook/modules/block/', '@blocks' => url('admin/structure/block'))) . '</p>';
      $output .= '<h3>' . t('Uses') . '</h3>';
      $output .= '<dl>';
      $output .= '<dt>' . t('Positioning content') . '</dt>';
      $output .= '<dd>' . t('When working with blocks, remember that all themes do <em>not</em> implement the same regions, or display regions in the same way. Blocks are positioned on a per-theme basis. Users with the <em>Administer blocks</em> permission can disable blocks. Disabled blocks are listed on the <a href="@blocks">Blocks administration page</a>, but are not displayed in any region.', array('@block' => 'http://drupal.org/handbook/modules/block/', '@blocks' => url('admin/structure/block'))) . '</dd>';
      $output .= '<dt>' . t('Controlling visibility') . '</dt>';
      $output .= '<dd>' . t('Blocks can be configured to be visible only on certain pages, only to users of certain roles, or only on pages displaying certain <a href="@content-type">content types</a>. Administrators can also allow specific blocks to be enabled or disabled by users when they edit their <a href="@user">My account</a> page. Some dynamic blocks, such as those generated by modules, will be displayed only on certain pages.', array('@content-type' => url('admin/structure/types'), '@user' => url('user'))) . '</dd>';
      $output .= '<dt>' . t('Creating custom blocks') . '</dt>';
      $output .= '<dd>' . t('Users with the <em>Administer blocks</em> permission can <a href="@block-add">add custom blocks</a>, which are then listed on the <a href="@blocks">Blocks administration page</a>. Once created, custom blocks behave just like default and module-generated blocks.', array('@blocks' => url('admin/structure/block'), '@block-add' => url('admin/structure/block/add'))) . '</dd>';
      $output .= '</dl>';
      return $output;
    case 'admin/structure/block/add':
      return '<p>' . t('Use this page to create a new custom block.') . '</p>';
  }
  if ($arg[0] == 'admin' && $arg[1] == 'structure' && $arg['2'] == 'block' && (empty($arg[3]) || $arg[3] == 'list')) {
    $demo_theme = !empty($arg[4]) ? $arg[4] : variable_get('theme_default', 'bartik');
    $themes = list_themes();
    $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. 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. Click the <em>configure</em> link next to each block to configure its specific title and visibility settings.') . '</p>';
    $output .= '<p>' . l(t('Demonstrate block regions (@theme)', array('@theme' => $themes[$demo_theme]->info['name'])), 'admin/structure/block/demo/' . $demo_theme) . '</p>';
    return $output;
  }
}

/**
 * Implements hook_theme().
 */
function block_theme() {
  return array(
    'block' => array(
      'render element' => 'elements',
      'template' => 'block',
    ),
    'block_admin_display_form' => array(
      'template' => 'block-admin-display-form',
      'file' => 'block.admin.inc',
      'render element' => 'form',
    ),
  );
}

/**
 * Implements hook_permission().
 */
function block_permission() {
  return array(
    'administer blocks' => array(
      'title' => t('Administer blocks'),
    ),
  );
}

/**
 * Implements hook_menu().
 */
function block_menu() {
  $default_theme = variable_get('theme_default', 'bartik');
  $items['admin/structure/block'] = array(
    'title' => 'Blocks',
    'description' => 'Configure what block content appears in your site\'s sidebars and other regions.',
    'page callback' => 'block_admin_display',
    'page arguments' => array($default_theme),
    'access arguments' => array('administer blocks'),
    'file' => 'block.admin.inc',
  );
  $items['admin/structure/block/manage/%/%'] = array(
    'title' => 'Configure block',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('block_admin_configure', 4, 5),
    'access arguments' => array('administer blocks'),
    'file' => 'block.admin.inc',
  );
  $items['admin/structure/block/manage/%/%/configure'] = array(
    'title' => 'Configure block',
    'type' => MENU_DEFAULT_LOCAL_TASK,
    'context' => MENU_CONTEXT_INLINE,
  );
  $items['admin/structure/block/manage/%/%/delete'] = array(
    'title' => 'Delete block',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('block_custom_block_delete', 4, 5),
    'access arguments' => array('administer blocks'),
    'type' => MENU_LOCAL_TASK,
    'context' => MENU_CONTEXT_NONE,
    'file' => 'block.admin.inc',
  );
  $items['admin/structure/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_ACTION,
    'file' => 'block.admin.inc',
  );
  foreach (list_themes() as $key => $theme) {
    $items['admin/structure/block/list/' . $key] = array(
      'title' => check_plain($theme->info['name']),
      'page arguments' => array($key),
      'type' => $key == $default_theme ? MENU_DEFAULT_LOCAL_TASK : MENU_LOCAL_TASK,
      'weight' => $key == $default_theme ? -10 : 0,
      'access callback' => '_block_themes_access',
      'access arguments' => array($theme),
      'file' => 'block.admin.inc',
    );
    if ($key != $default_theme) {
      $items['admin/structure/block/list/' . $key . '/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_ACTION,
        'file' => 'block.admin.inc',
      );
    }
    $items['admin/structure/block/demo/' . $key] = array(
      'title' => check_plain($theme->info['name']),
      'page callback' => 'block_admin_demo',
      'page arguments' => array($key),
      'type' => MENU_CALLBACK,
      'access callback' => '_block_themes_access',
      'access arguments' => array($theme),
      'theme callback' => '_block_custom_theme',
      'theme arguments' => array($key),
      'file' => 'block.admin.inc',
    );
  }
  return $items;
}

/**
 * Menu item access callback - only admin or enabled themes can be accessed.
 */
function _block_themes_access($theme) {
  return user_access('administer blocks') && drupal_theme_access($theme);
}

/**
 * Theme callback for the block configuration pages.
 *
 * @param $theme
 *   The theme whose blocks are being configured. If not set, the default theme
 *   is assumed.
 * @return
 *   The theme that should be used for the block configuration page, or NULL
 *   to indicate that the default theme should be used.
 */
function _block_custom_theme($theme = NULL) {
  // We return exactly what was passed in, to guarantee that the page will
  // always be displayed using the theme whose blocks are being configured.
  return $theme;
}

/**
 * Implements hook_block_info().
 */
function block_block_info() {
  $blocks = array();

  $result = db_query('SELECT bid, info FROM {block_custom} ORDER BY info');
  foreach ($result as $block) {
    $blocks[$block->bid]['info'] = $block->info;
    // Not worth caching.
    $blocks[$block->bid]['cache'] = DRUPAL_NO_CACHE;
  }
  return $blocks;
}

/**
 * Implements hook_block_configure().
 */
function block_block_configure($delta = 0) {
  if ($delta) {
    $custom_block = block_custom_block_get($delta);
  }
  else {
    $custom_block = array();
  }
  return block_custom_block_form($custom_block);
}

/**
 * Implements hook_block_save().
 */
function block_block_save($delta = 0, $edit = array()) {
  block_custom_block_save($edit, $delta);
}

/**
 * Implements hook_block_view().
 *
 * Generates the administrator-defined blocks for display.
 */
function block_block_view($delta = '') {
  $block = db_query('SELECT body, format FROM {block_custom} WHERE bid = :bid', array(':bid' => $delta))->fetchObject();
  $data['subject'] = NULL;
  $data['content'] = check_markup($block->body, $block->format, '', TRUE);
  return $data;
}

/**
 * Implements hook_page_build().
 *
 * Render blocks into their regions.
 */
function block_page_build(&$page) {
  global $theme;

  // The theme system might not yet be initialized. We need $theme.
  drupal_theme_initialize();

  // Populate all block regions
  $all_regions = system_region_list($theme);

  $item = menu_get_item();
  if ($item['path'] != 'admin/structure/block/demo/' . $theme) {
    // Load all region content assigned via blocks.
    foreach (array_keys($all_regions) as $region) {
      // Assign blocks to region.
      if ($blocks = block_get_blocks_by_region($region)) {
        $page[$region] = $blocks;
      }
    }
    // Once we've finished attaching all blocks to the page, clear the static
    // cache to allow modules to alter the block list differently in different
    // contexts. For example, any code that triggers hook_page_build() more
    // than once in the same page request may need to alter the block list
    // differently each time, so that only certain parts of the page are
    // actually built. We do not clear the cache any earlier than this, though,
    // because it is used each time block_get_blocks_by_region() gets called
    // above.
    drupal_static_reset('block_list');
  }
  else {
    // Append region description if we are rendering the regions demo page.
    $item = menu_get_item();
    if ($item['path'] == 'admin/structure/block/demo/' . $theme) {
      $visible_regions = array_keys(system_region_list($theme, REGIONS_VISIBLE));
      foreach ($visible_regions as $region) {
        $description = '<div class="block-region">' . $all_regions[$region] . '</div>';
        $page[$region]['block_description'] = array(
          '#markup' => $description,
          '#weight' => 15,
        );
      }
      $page['page_top']['backlink'] = array(
        '#type' => 'link',
        '#title' => t('Exit block region demonstration'),
        '#href' => 'admin/structure/block' . (variable_get('theme_default', 'bartik') == $theme ? '' : '/list/' . $theme),
        // Add the "overlay-restore" class to indicate this link should restore
        // the context in which the region demonstration page was opened.
        '#options' => array('attributes' => array('class' => array('block-demo-backlink', 'overlay-restore'))),
        '#weight' => -10,
      );
    }
  }
}

/**
 * Get a renderable array of a region containing all enabled blocks.
 *
 * @param $region
 *   The requested region.
 */
function block_get_blocks_by_region($region) {
  $build = array();
  if ($list = block_list($region)) {
    $build = _block_get_renderable_array($list);
  }
  return $build;
}

/**
 * Get an array of blocks suitable for drupal_render().
 *
 * @param $list
 *   A list of blocks such as that returned by block_list().
 * @return
 *   A renderable array.
 */
function _block_get_renderable_array($list = array()) {
  $weight = 0;
  $build = array();
  foreach ($list as $key => $block) {
    $build[$key] = $block->content;
    unset($block->content);

    // Add contextual links for this block; skip the main content block, since
    // contextual links are basically output as tabs/local tasks already. Also
    // skip the help block, since we assume that most users do not need or want
    // to perform contextual actions on the help block, and the links needlessly
    // draw attention on it.
    if ($key != 'system_main' && $key != 'system_help') {
      $build[$key]['#contextual_links']['block'] = array('admin/structure/block/manage', array($block->module, $block->delta));
    }

    $build[$key] += array(
      '#block' => $block,
      '#weight' => ++$weight,
    );
    $build[$key]['#theme_wrappers'][] ='block';
  }
  $build['#sorted'] = TRUE;
  return $build;
}

/**
 * Update the 'block' DB table with the blocks currently exported by modules.
 *
 * @paramĀ $theme
 *   The theme to rehash blocks for. If not provided, defaults to the currently
 *   used theme.
 *
 * @return
 *   Blocks currently exported by modules.
 */
function _block_rehash($theme = NULL) {
  global $theme_key;

  drupal_theme_initialize();
  if (!isset($theme)) {
    // If theme is not specifically set, rehash for the current theme.
    $theme = $theme_key;
  }
  $regions = system_region_list($theme);

  // These are the blocks the function will return.
  $blocks = array();
  // These are the blocks defined by code and modified by the database.
  $current_blocks = array();
  // These are {block}.bid values to be kept.
  $bids = array();
  $or = db_or();
  // Gather the blocks defined by modules.
  foreach (module_implements('block_info') as $module) {
    $module_blocks = module_invoke($module, 'block_info');
    foreach ($module_blocks as $delta => $block) {
      // Compile a condition to retrieve this block from the database.
      $condition = db_and()
        ->condition('module', $module)
        ->condition('delta', $delta);
      $or->condition($condition);
      // Add identifiers.
      $block['module'] = $module;
      $block['delta']  = $delta;
      $block['theme']  = $theme;
      $current_blocks[$module][$delta] = $block;
    }
  }
  // Save the blocks defined in code for alter context.
  $code_blocks = $current_blocks;
  $database_blocks = db_select('block', 'b')
    ->fields('b')
    ->condition($or)
    ->condition('theme', $theme)
    ->execute();
  foreach ($database_blocks as $block) {
    // Preserve info which is not in the database.
    $block->info = $current_blocks[$block->module][$block->delta]['info'];
    // The cache mode can only by set from hook_block_info(), so that has
    // precedence over the database's value.
    if (isset($current_blocks[$block->module][$block->delta]['cache'])) {
      $block->cache = $current_blocks[$block->module][$block->delta]['cache'];
    }
    // Blocks stored in the database override the blocks defined in code.
    $current_blocks[$block->module][$block->delta] = get_object_vars($block);
    // Preserve this block.
    $bids[$block->bid] = $block->bid;
  }
  drupal_alter('block_info', $current_blocks, $theme, $code_blocks);
  foreach ($current_blocks as $module => $module_blocks) {
    foreach ($module_blocks as $delta => $block) {
      if (!isset($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.
        $block['pages']  = '';
      }
      // Make sure weight is set.
      if (!isset($block['weight'])) {
        $block['weight'] = 0;
      }
      if (!empty($block['region']) && $block['region'] != BLOCK_REGION_NONE && !isset($regions[$block['region']])) {
        drupal_set_message(t('The block %info was assigned to the invalid region %region and has been disabled.', array('%info' => $block['info'], '%region' => $block['region'])), 'warning');
        // Disabled modules are moved into the BLOCK_REGION_NONE later so no
        // need to move the bock to another region.
        $block['status'] = 0;
      }
      // Set region to none if not enabled and make sure status is set.
      if (empty($block['status'])) {
        $block['status'] = 0;
        $block['region'] = BLOCK_REGION_NONE;
      }
      // There is no point saving disabled blocks. Still, we need to save them
      // because the 'title' attribute is saved to the {blocks} table.
      if (isset($block['bid'])) {
        // If the block has a bid property, it comes from the database and
        // the record needs to be updated, so set the primary key to 'bid'
        // before passing to drupal_write_record().
        $primary_keys = array('bid');
        // Remove a block from the list of blocks to keep if it became disabled.
        unset($bids[$block['bid']]);
      }
      else {
        $primary_keys = array();
      }
      drupal_write_record('block', $block, $primary_keys);
      // Add to the list of blocks we return.
      $blocks[] = $block;
    }
  }
  if ($bids) {
    // Remove disabled that are no longer defined by the code from the
    // database.
    db_delete('block')
      ->condition('bid', $bids, 'NOT IN')
      ->condition('theme', $theme)
      ->execute();
  }
  return $blocks;
}

/**
 * Returns information from database about a user-created (custom) block.
 *
 * @param $bid
 *   ID of the block to get information for.
 * @return
 *   Associative array of information stored in the database for this block.
 *   Array keys:
 *   - bid: Block ID.
 *   - info: Block description.
 *   - body: Block contents.
 *   - format: Filter ID of the filter format for the body.
 */
function block_custom_block_get($bid) {
  return db_query("SELECT * FROM {block_custom} WHERE bid = :bid", array(':bid' => $bid))->fetchAssoc();
}

/**
 * Define the custom block form.
 */
function block_custom_block_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">Blocks administration page</a>.', array('@overview' => url('admin/structure/block'))),
    '#required' => TRUE,
    '#weight' => -19,
  );
  $form['body_field']['#weight'] = -17;
  $form['body_field']['body'] = array(
    '#type' => 'text_format',
    '#title' => t('Block body'),
    '#default_value' => $edit['body'],
    '#format' => isset($edit['format']) ? $edit['format'] : NULL,
    '#rows' => 15,
    '#description' => t('The content of the block as shown to the user.'),
    '#required' => TRUE,
    '#weight' => -17,
  );

  return $form;
}

/**
 * Saves a user-created block in the database.
 *
 * @param $edit
 *   Associative array of fields to save. Array keys:
 *   - info: Block description.
 *   - body: Associative array of body value and format.  Array keys:
 *     - value: Block contents.
 *     - format: Filter ID of the filter format for the body.
 * @param $delta
 *   Block ID of the block to save.
 * @return
 *   Always returns TRUE.
 */
function block_custom_block_save($edit, $delta) {
  db_update('block_custom')
    ->fields(array(
      'body' => $edit['body']['value'],
      'info' => $edit['info'],
      'format' => $edit['body']['format'],
    ))
    ->condition('bid', $delta)
    ->execute();
  return TRUE;
}

/**
 * Implements hook_form_FORM_ID_alter().
 */
function block_form_user_profile_form_alter(&$form, &$form_state) {
  if ($form['#user_category'] == 'account') {
    $account = $form['#user'];
    $rids = array_keys($account->roles);
    $result = db_query("SELECT DISTINCT b.* FROM {block} b LEFT JOIN {block_role} r ON b.module = r.module AND b.delta = r.delta WHERE b.status = 1 AND b.custom <> 0 AND (r.rid IN (:rids) OR r.rid IS NULL) ORDER BY b.weight, b.module", array(':rids' => $rids));

    $blocks = array();
    foreach ($result as $block) {
      $data = module_invoke($block->module, 'block_info');
      if ($data[$block->delta]['info']) {
        $blocks[$block->module][$block->delta] = array(
          '#type' => 'checkbox',
          '#title' => check_plain($data[$block->delta]['info']),
          '#default_value' => isset($account->data['block'][$block->module][$block->delta]) ? $account->data['block'][$block->module][$block->delta] : ($block->custom == 1),
        );
      }
    }
    // Only display the fieldset if there are any personalizable blocks.
    if ($blocks) {
      $form['block'] = array(
        '#type' => 'fieldset',
        '#title' => t('Personalize blocks'),
        '#description' => t('Blocks consist of content or information that complements the main content of the page. Enable or disable optional blocks using the checkboxes below.'),
        '#weight' => 3,
        '#collapsible' => TRUE,
        '#tree' => TRUE,
      );
      $form['block'] += $blocks;
    }
  }
}

/**
 * Implements hook_user_presave().
 */
function block_user_presave(&$edit, $account, $category) {
  if (isset($edit['block'])) {
    $edit['data']['block'] = $edit['block'];
  }
}

/**
 * Initialize blocks for enabled themes.
 */
function block_themes_enabled($theme_list) {
  foreach ($theme_list as $theme) {
    block_theme_initialize($theme);
  }
}

/**
 * Assign an initial, default set of blocks for a theme.
 *
 * This function is called the first time a new theme is enabled. The new theme
 * gets a copy of the default theme's blocks, with the difference that if a
 * particular region isn't available in the new theme, the block is assigned
 * to the new theme's default region.
 *
 * @param $theme
 *   The name of a theme.
 */
function block_theme_initialize($theme) {
  // Initialize theme's blocks if none already registered.
  $has_blocks = (bool) db_query_range('SELECT 1 FROM {block} WHERE theme = :theme', 0, 1, array(':theme' => $theme))->fetchField();
  if (!$has_blocks) {
    $default_theme = variable_get('theme_default', 'bartik');
    $regions = system_region_list($theme);
    $result = db_query("SELECT * FROM {block} WHERE theme = :theme", array(':theme' => $default_theme), array('fetch' => PDO::FETCH_ASSOC));
    foreach ($result as $block) {
      // If the region isn't supported by the theme, assign the block to the theme's default region.
      if ($block['status'] && !isset($regions[$block['region']])) {
        $block['region'] = system_default_region($theme);
      }
      $block['theme'] = $theme;
      unset($block['bid']);
      drupal_write_record('block', $block);
    }
  }
}

/**
 * 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) {
  $blocks = &drupal_static(__FUNCTION__);

  if (!isset($blocks)) {
    $blocks = _block_load_blocks();
  }

  // Create an empty array if there are no entries.
  if (!isset($blocks[$region])) {
    $blocks[$region] = array();
  }
  else {
    $blocks[$region] = _block_render_blocks($blocks[$region]);
  }

  return $blocks[$region];
}

/**
 * Load a block object from the database.
 *
 * @param $module
 *   Name of the module that implements the block to load.
 * @param $delta
 *   Unique ID of the block within the context of $module. Pass NULL to return
 *   an empty $block object for $module.
 *
 * @return
 *   A block object.
 */
function block_load($module, $delta) {
  if (isset($delta)) {
    $block = db_query('SELECT * FROM {block} WHERE module = :module AND delta = :delta', array(':module' => $module, ':delta' => $delta))->fetchObject();
  }

  // If the block does not exist in the database yet return a stub block
  // object.
  if (empty($block)) {
    $block = new stdClass();
    $block->module = $module;
    $block->delta = $delta;
  }

  return $block;
}

/**
 * Load blocks information from the database.
 */
function _block_load_blocks() {
  global $theme_key;

  $query = db_select('block', 'b');
  $result = $query
    ->fields('b')
    ->condition('b.theme', $theme_key)
    ->condition('b.status', 1)
    ->orderBy('b.region')
    ->orderBy('b.weight')
    ->orderBy('b.module')
    ->addTag('block_load')
    ->addTag('translatable')
    ->execute();

  $block_info = $result->fetchAllAssoc('bid');
  // Allow modules to modify the block list.
  drupal_alter('block_list', $block_info);

  $blocks = array();
  foreach ($block_info as $block) {
    $blocks[$block->region]["{$block->module}_{$block->delta}"] = $block;
  }
  return $blocks;
}

/**
 * Implements hook_block_list_alter().
 *
 * Check the page, user role and user specific visibilty settings.
 * Remove the block if the visibility conditions are not met.
 */
function block_block_list_alter(&$blocks) {
  global $user, $theme_key;

  // Build an array of roles for each block.
  $block_roles = array();
  $result = db_query('SELECT module, delta, rid FROM {block_role}');
  foreach ($result as $record) {
    $block_roles[$record->module][$record->delta][] = $record->rid;
  }

  foreach ($blocks as $key => $block) {
    if (!isset($block->theme) || !isset($block->status) || $block->theme != $theme_key || $block->status != 1) {
      // This block was added by a contrib module, leave it in the list.
      continue;
    }

    // If a block has no roles associated, it is displayed for every role.
    // For blocks with roles associated, if none of the user's roles matches
    // the settings from this block, remove it from the block list.
    if (isset($block_roles[$block->module][$block->delta]) && !array_intersect($block_roles[$block->module][$block->delta], array_keys($user->roles))) {
      // No match.
      unset($blocks[$key]);
      continue;
    }

    // Use the user's block visibility setting, if necessary.
    if ($block->custom != BLOCK_CUSTOM_FIXED) {
      if ($user->uid && isset($user->data['block'][$block->module][$block->delta])) {
        $enabled = $user->data['block'][$block->module][$block->delta];
      }
      else {
        $enabled = ($block->custom == BLOCK_CUSTOM_ENABLED);
      }
    }
    else {
      $enabled = TRUE;
    }
    if (!$enabled) {
      unset($blocks[$key]);
      continue;
    }

    // Match path if necessary.
    if ($block->pages) {
      // Convert path to lowercase. This allows comparison of the same path
      // with different case. Ex: /Page, /page, /PAGE.
      $pages = drupal_strtolower($block->pages);
      if ($block->visibility < BLOCK_VISIBILITY_PHP) {
        // Convert the Drupal path to lowercase
        $path = drupal_strtolower(drupal_get_path_alias($_GET['q']));
        // Compare the lowercase internal and lowercase path alias (if any).
        $page_match = drupal_match_path($path, $pages);
        if ($path != $_GET['q']) {
          $page_match = $page_match || drupal_match_path($_GET['q'], $pages);
        }
        // When $block->visibility has a value of 0 (BLOCK_VISIBILITY_NOTLISTED),
        // the block is displayed on all pages except those listed in $block->pages.
        // When set to 1 (BLOCK_VISIBILITY_LISTED), it is displayed only on those
        // pages listed in $block->pages.
        $page_match = !($block->visibility xor $page_match);
      }
      elseif (module_exists('php')) {
        $page_match = php_eval($block->pages);
      }
      else {
        $page_match = FALSE;
      }
    }
    else {
      $page_match = TRUE;
    }
    if (!$page_match) {
      unset($blocks[$key]);
    }
  }
}

/**
 * Render the content and subject for a set of blocks.
 *
 * @param $region_blocks
 *   An array of block objects such as returned for one region by _block_load_blocks().
 *
 * @return
 *   An array of visible blocks as expected by drupal_render().
 */
function _block_render_blocks($region_blocks) {
  foreach ($region_blocks 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($region_blocks[$key]);
      // 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'
      // (or 'HEAD').
      if (!count(module_implements('node_grants')) && ($_SERVER['REQUEST_METHOD'] == 'GET' || $_SERVER['REQUEST_METHOD'] == 'HEAD') && ($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);

        // Allow modules to modify the block before it is viewed, via either
        // hook_block_view_alter() or hook_block_view_MODULE_DELTA_alter().
        drupal_alter(array('block_view', "block_view_{$block->module}_{$block->delta}"), $array, $block);

        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) && $block->content) {
        // Normalize to the drupal_render() structure.
        if (is_string($block->content)) {
          $block->content = array('#markup' => $block->content);
        }
        // Override default block title if a custom display title is present.
        if ($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 = '';
        }
        $region_blocks["{$block->module}_{$block->delta}"] = $block;
      }
    }
  }
  return $region_blocks;
}

/**
 * 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 differentiated.
 *
 * @param $block
 * @return
 *   The string used as cache_id for the block.
 */
function _block_get_cache_id($block) {
  global $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', FALSE) && !in_array($block->cache, array(DRUPAL_NO_CACHE, DRUPAL_CACHE_CUSTOM)) && $user->uid != 1) {
    // Start with common sub-patterns: block identification, theme, language.
    $cid_parts[] = $block->module;
    $cid_parts[] = $block->delta;
    $cid_parts = array_merge($cid_parts, drupal_render_cid_parts($block->cache));

    return implode(':', $cid_parts);
  }
}

/**
 * Implements hook_flush_caches().
 */
function block_flush_caches() {
  // Rehash blocks for active themes. We don't use list_themes() here,
  // because if MAINTENANCE_MODE is defined it skips reading the database,
  // and we can't tell which themes are active.
  $themes = db_query("SELECT name FROM {system} WHERE type = 'theme' AND status = 1");
  foreach ($themes as $theme) {
    _block_rehash($theme->name);
  }

  return array('cache_block');
}

/**
 * Process variables for block.tpl.php
 *
 * Prepare the values passed to the theme_block function to be passed
 * into a pluggable template engine. Uses block properties to generate a
 * series of template file suggestions. If none are found, the default
 * block.tpl.php is used.
 *
 * Most themes utilize their own copy of block.tpl.php. The default is located
 * inside "modules/block/block.tpl.php". Look in there for the full list of
 * variables.
 *
 * The $variables array contains the following arguments:
 * - $block
 *
 * @see block.tpl.php
 */
function template_preprocess_block(&$variables) {
  $block_counter = &drupal_static(__FUNCTION__, array());
  $variables['block'] = $variables['elements']['#block'];
  // All blocks get an independent counter for each region.
  if (!isset($block_counter[$variables['block']->region])) {
    $block_counter[$variables['block']->region] = 1;
  }
  // Same with zebra striping.
  $variables['block_zebra'] = ($block_counter[$variables['block']->region] % 2) ? 'odd' : 'even';
  $variables['block_id'] = $block_counter[$variables['block']->region]++;

  // Create the $content variable that templates expect.
  $variables['content'] = $variables['elements']['#children'];

  $variables['classes_array'][] = drupal_html_class('block-' . $variables['block']->module);

  $variables['theme_hook_suggestions'][] = 'block__' . $variables['block']->region;
  $variables['theme_hook_suggestions'][] = 'block__' . $variables['block']->module;
  $variables['theme_hook_suggestions'][] = 'block__' . $variables['block']->module . '__' . $variables['block']->delta;

  // Create a valid HTML ID and make sure it is unique.
  $variables['block_html_id'] = drupal_html_id('block-' . $variables['block']->module . '-' . $variables['block']->delta);
}

/**
 * Implements hook_user_role_delete().
 *
 * Remove deleted role from blocks that use it.
 */
function block_user_role_delete($role) {
  db_delete('block_role')
    ->condition('rid', $role->rid)
    ->execute();
}

/**
 * Implements hook_menu_delete().
 */
function block_menu_delete($menu) {
  db_delete('block')
    ->condition('module', 'menu')
    ->condition('delta', $menu['menu_name'])
    ->execute();
  db_delete('block_role')
    ->condition('module', 'menu')
    ->condition('delta', $menu['menu_name'])
    ->execute();
}

/**
 * Implements hook_form_FORM_ID_alter().
 */
function block_form_system_performance_settings_alter(&$form, &$form_state) {
  $disabled = count(module_implements('node_grants'));
  $form['caching']['block_cache'] = array(
    '#type' => 'checkbox',
    '#title' => t('Cache blocks'),
    '#default_value' => variable_get('block_cache', FALSE),
    '#disabled' => $disabled,
    '#description' => $disabled ? t('Block caching is inactive because you have enabled modules defining content access restrictions.') : NULL,
    '#weight' => -1,
  );
}

/**
 * Implements hook_admin_paths().
 */
function block_admin_paths() {
  $paths = array(
    // Exclude the block demonstration page from admin (overlay) treatment.
    // This allows us to present this page in its true form, full page.
    'admin/structure/block/demo/*' => FALSE,
  );
  return $paths;
}

/**
 * Implements hook_modules_uninstalled().
 *
 * Cleanup {block} and {block_role} tables from modules' blocks.
 */
function block_modules_uninstalled($modules) {
  db_delete('block')
    ->condition('module', $modules, 'IN')
    ->execute();
  db_delete('block_role')
    ->condition('module', $modules, 'IN')
    ->execute();
}

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