query_registry.module

<?php

/**
 * @file
 * Primary hook implementations.
 */

// Hooks.
const QUERY_REGISTRY_REGISTER_IMPLEMENTATION = 'query_registry_register_implementations';
const QUERY_REGISTRY_REGISTER_QUERY = 'query_registry_register_queries';

const QUERY_REGISTRY_DEFAULT = 'module_default';

/**
 * Implements hook_menu().
 */
function query_registry_menu() {
  return array(
    'admin/config/search/query_registry' => array(
      'title' => 'Query Registry Configuration',
      'description' => 'Select which queries to use.',
      'page callback' => 'drupal_get_form',
      'page arguments' => array('query_registry_admin_form'),
      'file' => 'includes/admin.form.inc',
      'access arguments' => array('administer site configuration'),
      'type' => MENU_NORMAL_ITEM,
    ),
  );
}

/**
 * Run the query as outlined in the registry.
 *
 * @param string $query_identifier
 *   The query to route.
 * @param array $query_args
 *   The parameters to pass to the query implementation.
 *
 * @return mixed
 *   NULL for use module default or the result of the query.
 */
function query_registry_run_query($query_identifier, $query_args = array()) {
  $query_definition = query_registry_get_query($query_identifier);
  // If module defaults are to be used return NULL.
  if (is_null($query_definition)) {
    return NULL;
  }
  // Include the necessary file.
  if (isset($query_definition['extension']) && isset($query_definition['filename'])) {
    $included = module_load_include(
      $query_definition['extension'],
      $query_definition['module'],
      $query_definition['filename']
    );
    if (!$included) {
      watchdog(
        'query_registry',
        'Could not include a query implementation. Please verify configuration.',
        array(),
        WATCHDOG_WARNING
      );
      return NULL;
    }
  }

  return call_user_func_array($query_definition['callable'], $query_args);
}

/**
 * Get the query as outlined in the registry.
 *
 * @param string $query_identifier
 *   The query to route.
 *
 * @return mixed
 *   NULL for use module default or the query array.
 */
function query_registry_get_query($query_identifier) {
  $query_registers = variable_get('query_registry_selected_queries', array());

  // If module defaults are to be used return NULL.
  if (!isset($query_registers[$query_identifier]) || $query_registers[$query_identifier] == QUERY_REGISTRY_DEFAULT) {
    return NULL;
  }

  $query_definitions = module_invoke($query_registers[$query_identifier], QUERY_REGISTRY_REGISTER_IMPLEMENTATION);
  return $query_definitions[$query_identifier];
}