groups/modules/commons/commons_search/commons_search.module

<?php
/**
 * commons_search.module
 * Code for the Commons Search feature.
 */

include_once 'commons_search.features.inc';

/**
 * Implements hook_module_implements_alter().
 */
function commons_search_module_implements_alter(&$implementations, $hook) {
  if ($hook == 'form_alter') {
    // We move commons_search to the end so it gets processed last.
    $group = $implementations['commons_search'];
    unset($implementations['commons_search']);
    $implementations['commons_search'] = $group;
  }
}

/**
 * Custom search form that switches between Core and Solr depending on which is
 * the enabled search module.
 */
function commons_search_form_alter(&$form, &$form_state, $form_id) {

  if ($form_id == 'search_block_form') {
    // Move the textfield to after the drop down.
    $site_key = 'c-all';
    $form['search_block_form']['#weight'] = 1;
    if (module_exists('commons_search_core')) {
      // We're using faceted core search, so change Site search key to reflect
      // the change of search engines.
      $site_key = 'o-search_facetapi';
    }
    else {
      if (module_exists('apachesolr_search')) {
        // Are we using Apache Solr? If so change the Site search key to reflect
        // the change of search engines.
        $site_key = 'o-solr';
      }
    }
    // Overwrite all options so we only have 3 (at most).
    $form['custom_search_types']['#options'] = array(
      $site_key => t('Site'),
      'c-user' => t('Users'),
    );
    $group = FALSE;
    $node = current_path();
    if ((strrpos($node, 'node/') !== FALSE || strrpos($node, 'group/') !== FALSE)
      && is_numeric(substr($node, strrpos($node, '/') + 1))
    ) {
      // If we're on a page that looks like a group node, see if it is actually
      // a group node.
      $node = node_load(substr($node, strrpos($node, '/') + 1));
      if (!empty($node)) {
        $group = ($node->type == 'group');
      }
    }
    if ($group) {
      // Current page is a group node, so add group search option to the
      // dropdown menu and set the current group id.
      $form['custom_search_types']['#options']['o-commons_search'] = t('This group');
      $form['custom_search_types']["#default_value"] = 'o-commons_search';
      $form_state['search_group_id'] = $node->nid;
    }
    if (arg(0) == 'search') {
      // If we've already searched, refill the search box with the current
      // search keywords.
      $form['search_block_form']['#default_value'] = check_plain(arg(2));
    }
    $keys = arg(2);
    if (!module_exists('commons_search_solr') && !empty($keys)) {
      // Remove the search keys from the form action only if we're using core search.
      $form['#action'] = str_replace("/" . check_plain(arg(2)), '', $form['#action']);
    }
  }
}

/**
 * Search form submit handler.
 * Add group id filter if appropriate.
 */
function commons_search_search_form_submit($form, &$form_state) {
  if ($form_state['values']['custom_search_types'] == 'o-commons_search'
    && isset($form_state['search_group_id'])
  ) {
    $keys = $form_state['values']['search_block_form'];
    if (module_exists('apachesolr_search')) {
      // Add on a filter to the solr query to only list results within the
      // specified group.
      $qm = (strpos($form_state['redirect'], '?') !== FALSE ? '' : '?');
      $form_state['redirect'] .= $qm . '&f[1]=sm_og_group_ref:node:' . $form_state['search_group_id'];
    }
    else {
      // Using core search to search within a group doesn't work, so we simply
      // use a view with exposed search terms to do the searching.
      drupal_goto('search/group/' . $form_state['search_group_id'], array('query' => array('keys' => $keys)));
    }
  }
  else {
    if ($form_state['values']['custom_search_types'] == 'c-user') {
      // Force update the redirect on User search since Custom Search is weird.
      $keys = check_plain($form_state['values']['search_block_form']);
      $form_state['redirect'] = 'search/user/' . $keys;
    }
  }
}

function commons_search_process_search_result(&$variables) {
}
/**
 * Implements hook_preprocess_hook().
 */
function commons_search_process_search_results(&$variables) {
  $variables['result_count'] = count($variables['results']);
  if (isset($variables['response'])
    && isset($variables['response']->request)
    && preg_match('/sm_og_group_ref:"node:([0-9]+)"&/', urldecode($variables['response']->request), $match)
  ) {
    $group = node_load($match[1]);
    $title = t('Search within !group', array('!group' => '<em>' . $group->title . '</em>'));
    $variables['title'] = $title;
  }
}

/**
 * Implements hook_theme_registry_alter().
 */
function commons_search_theme_registry_alter(&$theme_registry) {
  // Remove AT breadcrumb preprocess since it adds raw RDFa data into the title.
  $theme_registry['breadcrumb']['preprocess functions'] = array_flip($theme_registry['breadcrumb']['preprocess functions']);
  unset($theme_registry['breadcrumb']['preprocess functions']['adaptivetheme_preprocess_breadcrumb']);
  $theme_registry['breadcrumb']['preprocess functions'] = array_flip($theme_registry['breadcrumb']['preprocess functions']);
}