source: sipes/modules_contrib/panels/panels_mini/panels_mini.module

<?php

/**
 * @file panels_mini.module
 *
 * This module provides mini panels which are basically panels that can be
 * used within blocks or other panels.
 */

/**
 * Implementation of hook_perm().
 */
function panels_mini_perm() {
  return array('create mini panels', 'administer mini panels');
}

/**
 * Implementation of hook_menu().
 */
function panels_mini_menu() {
  // Safety: go away if CTools is not at an appropriate version.
  if (!defined('PANELS_REQUIRED_CTOOLS_API') || !module_invoke('ctools', 'api_version', PANELS_REQUIRED_CTOOLS_API)) {
    return array();
  }
  require_once drupal_get_path('module', 'panels_mini') . '/panels_mini.admin.inc';
  return _panels_mini_menu();
}

// ---------------------------------------------------------------------------
// Allow the rest of the system access to mini panels

/**
 * Implementation of hook_block().
 *
 * Expose qualifying mini panels to Drupal's block system.
 */
function panels_mini_block($op = 'list', $delta = 0, $edit = array()) {
  // Safety: go away if CTools is not at an appropriate version.
  if (!defined('PANELS_REQUIRED_CTOOLS_API') || !module_invoke('ctools', 'api_version', PANELS_REQUIRED_CTOOLS_API)) {
    return array();
  }

  if ($op == 'list') {
    $blocks = array();

    $minis = panels_mini_load_all();
    foreach ($minis as $panel_mini) {
      if (empty($mini->disabled) && empty($mini->requiredcontext)) {
        $blocks[$panel_mini->name] = array(
          'info' => t('Mini panel: "@title"', array('@title' => $panel_mini->admin_title)),
          'cache' => BLOCK_NO_CACHE,
        );
      }
    }

    return $blocks;
  }
  elseif ($op == 'view') {
    // static recursion protection.
    static $viewing = array();
    if (!empty($viewing[$delta])) {
      return;
    }
    $viewing[$delta] = TRUE;

    $panel_mini = panels_mini_load($delta);
    if (empty($panel_mini)) {
      // Bail out early if the specified mini panel doesn't exist.
      return;
    }

    ctools_include('context');
    $panel_mini->context = $panel_mini->display->context = ctools_context_load_contexts($panel_mini);
    $panel_mini->display->css_id = panels_mini_get_id($panel_mini->name);

    $block = array();

    $block['content'] = panels_render_display($panel_mini->display);
    $block['subject'] = $panel_mini->display->get_title();

    unset($viewing[$delta]);
    return $block;
  }
  elseif ($op = 'configure') {
    return array(
      'admin-shortcut' => array(
        '#value' => l(t('Manage this mini-panel'), "admin/build/mini-panels/list/$delta/edit")
      ),
    );
  }
}

/**
 * Statically store all used IDs to ensure all mini panels get a unique id.
 */
function panels_mini_get_id($name) {
  static $id_cache = array();

  $id = 'mini-panel-' . $name;
  if (!empty($id_cache[$name])) {
    $id .= "-" . $id_cache[$name]++;
  }
  else {
    $id_cache[$name] = 1;
  }

  return $id;
}

// ---------------------------------------------------------------------------
// Database functions.

/**
 * Create a new page with defaults appropriately set from schema.
 */
function panels_mini_new($set_defaults = TRUE) {
  ctools_include('export');
  return ctools_export_new_object('panels_mini', $set_defaults);
}

/**
 * Load a single mini panel.
 */
function panels_mini_load($name) {
  $cache = &ctools_static('panels_mini_load_all', array());

  // We use array_key_exists because failed loads will be NULL and
  // isset() will try to load it again.
  if (!array_key_exists($name, $cache)) {
    ctools_include('export');
    $result = ctools_export_load_object('panels_mini', 'names', array($name));
    if (isset($result[$name])) {
      if (empty($result[$name]->display)) {
        $result[$name]->display = panels_load_display($result[$name]->did);
        if (!empty($result[$name]->title) && empty($result[$name]->display->title)) {
          $result[$name]->display->title = $result[$name]->title;
        }
      }
      $cache[$name] = $result[$name];
      if (!empty($result[$name]->title) && empty($result[$name]->admin_title)) {
        $cache[$name]->admin_title = $result[$name]->title;
      }
    }
    else {
      $cache[$name] = NULL;
    }
  }

  if (isset($cache[$name])) {
    return $cache[$name];
  }
}

/**
 * Load all mini panels.
 */
function panels_mini_load_all($reset = FALSE) {
  $cache = &ctools_static('panels_mini_load_all', array());
  static $all_loaded = FALSE;

  // We check our own private static because individual minis could have
  // been loaded prior to load all and we need to know that.
  if (!$all_loaded || $reset) {
    $all_loaded = TRUE;
    if ($reset) {
      $cache = array();
    }

    ctools_include('export');
    $minis = ctools_export_load_object('panels_mini');
    $dids = array();
    foreach ($minis as $mini) {
      if (empty($cache[$mini->name])) {
        if (!empty($mini->did)) {
          $dids[$mini->did] = $mini->name;
        }
        else {
        // Translate old style titles into new titles.
          if (!empty($mini->title) && empty($mini->display->title)) {
            $mini->display->title = $mini->title;
          }
        }
        // Translate old style titles into new titles.
        if (isset($mini->title) && empty($mini->admin_title)) {
          $mini->admin_title = $mini->title;
        }
        $cache[$mini->name] = $mini;
      }
    }

    $displays = panels_load_displays(array_keys($dids));
    foreach ($displays as $did => $display) {
      if (!empty($cache[$dids[$did]]->title) && empty($display->title)) {
        $display->title = $cache[$dids[$did]]->title;
      }
      $cache[$dids[$did]]->display = $display;
    }
  }

  return $cache;
}

/**
 * Write a mini panel to the database.
 */
function panels_mini_save(&$mini) {
  if (!empty($mini->display)) {
    $display = panels_save_display($mini->display);
    $mini->did = $display->did;
  }

  $update = (isset($mini->pid) && $mini->pid != 'new') ? array('pid') : array();
  drupal_write_record('panels_mini', $mini, $update);

  return $mini;
}

/**
 * Remove a mini panel.
 */
function panels_mini_delete($mini) {
  db_query("DELETE FROM {panels_mini} WHERE name = '%s'", $mini->name);
  if ($mini->type != t('Overridden')) {
    db_query("DELETE FROM {blocks} WHERE module = 'panels_mini' AND delta = '%s'", $mini->name);
  }
  return panels_delete_display($mini->did);
}

/**
 * Export a mini panel.
 */
function panels_mini_export($mini, $indent = '') {
  ctools_include('export');
  $output = ctools_export_object('panels_mini', $mini, $indent);
  // Export the primary display
  $display = !empty($mini->display) ? $mini->display : panels_load_display($mini->did);
  $output .= panels_export_display($display, $indent);
  $output .= $indent . '$mini->display = $display' . ";\n";
  return $output;
}

/**
 * Remove the block version of mini panels from being available content types.
 */
function panels_mini_ctools_block_info($module, $delta, &$info) {
  $info = NULL;
}

/**
 * Implementation of hook_ctools_plugin_directory() to let the system know
 * we implement task and task_handler plugins.
 */
function panels_mini_ctools_plugin_directory($module, $plugin) {
  if ($module == 'ctools' && ($plugin == 'content_types' || $plugin == 'export_ui')) {
    return 'plugins/' . $plugin;
  }
}

/**
 * Get the display cache for the panels_mini plugin.
 */
function _panels_mini_panels_cache_get($key) {
  ctools_include('export-ui');
  $plugin = ctools_get_export_ui('panels_mini');
  $handler = ctools_export_ui_get_handler($plugin);
  if (!$handler) {
    return;
  }

  $item = $handler->edit_cache_get($key);
  if (!$item) {
    $item = ctools_export_crud_load($handler->plugin['schema'], $key);
  }

  return array($handler, $item);
}

/**
 * Get display edit cache for the panels mini export UI
 *
 * The key is the second half of the key in this form:
 * panels_mini:TASK_NAME:HANDLER_NAME;
 */
function panels_mini_panels_cache_get($key) {
  ctools_include('common', 'panels');
  list($handler, $item) = _panels_mini_panels_cache_get($key);
  if (isset($item->mini_panels_display_cache)) {
    return $item->mini_panels_display_cache;
  }

  $cache = new stdClass();
  $cache->display = $item->display;
  $cache->display->context = ctools_context_load_contexts($item);
  $cache->display->cache_key = 'panels_mini:' . $key;
  $cache->content_types = panels_common_get_allowed_types('panels_mini', $cache->display->context);
  $cache->display_title = TRUE;

  // @TODO support locking
  $cache->locked = FALSE;

  return $cache;
}

/**
 * Store a display edit in progress in the page cache.
 */
function panels_mini_panels_cache_set($key, $cache) {
  list($handler, $item) = _panels_mini_panels_cache_get($key);
  $item->mini_panels_display_cache = $cache;
  $handler->edit_cache_set_key($item, $key);
}

/**
 * Save all changes made to a display using the panels mini UI cache.
 */
function panels_mini_panels_cache_clear($key, $cache) {
  list($handler, $item) = _panels_mini_panels_cache_get($key);
  $handler->edit_cache_clear($item);
}

/**
 * Save all changes made to a display using the panels mini UI cache.
 */
function panels_mini_panels_cache_save($key, $cache) {
  list($handler, $item) = _panels_mini_panels_cache_get($key);
  $item->display = $cache->display;
  panels_mini_save($item);

  $handler->edit_cache_clear($item);
}

/**
 * Break the lock on a panels mini page.
 */
function panels_mini_panels_cache_break_lock($key, $cache) {
}

/**
 * Alter default mini panels to ensure they have new fields and avoid warnings.
 */
function panels_mini_default_panels_mini_alter(&$minis) {
  foreach ($minis as $name => $mini) {
    if (!isset($mini->admin_description)) {
      $minis[$name]->admin_description = '';
    }
  }
}

/**
 * Implementation of hook_panels_dashboard_blocks().
 *
 * Adds mini panels information to the Panels dashboard.
 */
function panels_mini_panels_dashboard_blocks(&$vars) {
  $vars['links']['panels_mini'] = array(
    'title' => l(t('Mini panel'), 'admin/build/mini-panels/add'),
    'description' => t('Mini panels are small content areas exposed as blocks, for when you need to have complex block layouts or layouts within layouts.'),
    'weight' => -1,
  );

  // Load all mini panels and their displays.
  $panel_minis = panels_mini_load_all();
  $count = 0;
  $rows = array();

  foreach ($panel_minis as $panel_mini) {
    $rows[] = array(
      check_plain($panel_mini->admin_title),
      array(
        'data' => l(t('Edit'), "admin/build/mini-panels/list/$panel_mini->name/edit"),
        'class' => 'links',
      ),
    );

    // Only show 10.
    if (++$count >= 10) {
      break;
    }
  }

  if ($rows) {
    $content = theme('table', array(), $rows, array('class' => 'panels-manage'));
  }
  else {
    $content = '<p>' . t('There are no mini panels.') . '</p>';
  }

  $vars['blocks']['panels_mini'] = array(
    'weight' => -100,
    'title' => t('Manage mini panels'),
    'link' => l(t('Go to list'), 'admin/build/mini-panels'),
    'content' => $content,
    'class' => 'dashboard-mini-panels',
    'section' => 'left',
  );

}