Club Drupal

<?php

/**

 * @file

 * Provides the view object type and associated methods.

 */

/**

 * @defgroup views_objects Objects that represent a View or part of a view

 * @{

 * These objects are the core of Views do the bulk of the direction and

 * storing of data. All database activity is in these objects.

 */

/**

 * An object to contain all of the data to generate a view, plus the member

 * functions to build the view query, execute the query and render the output.

 */

class view extends views_db_object {

  var $db_table = 'views_view';

  var $base_table = 'node';

  var $base_field = 'nid';

  /**

   * The name of the view.

   *

   * @var string

   */

  var $name = "";

  /**

   * The id of the view, which is used only for views in the database.

   *

   * @var number

   */

  var $vid;

  /**

   * The description of the view, which is used only in the interface.

   *

   * @var string

   */

  var $description;

  /**

   * The "tags" of a view.

   * The tags are stored as a single string, though it is used as multiple tags

   * for example in the views overview.

   *

   * @var string

   */

  var $tag;

  /**

   * The human readable name of the view.

   *

   * @var string

   */

  var $human_name;

  /**

   * The core version the view was created for.

   * @var int

   */

  var $core;

  /**

   * The views-api version this view was created by.

   *

   * Some examples of the variable are 3.0 or 3.0-alpha1

   *

   * @var string

   */

  var $api_version;

  /**

   * Is the view disabled.

   *

   * This value is used for exported view, to provide some default views which aren't enabled.

   *

   * @var bool

   */

  var $disabled;

  // State variables

  var $built = FALSE;

  var $executed = FALSE;

  var $editing = FALSE;

  var $args = array();

  var $build_info = array();

  var $use_ajax = FALSE;

  /**

   * Where the results of a query will go.

   *

   * The array must use a numeric index starting at 0.

   *

   * @var array

   */

  var $result = array();

  // May be used to override the current pager info.

  var $current_page = NULL;

  var $items_per_page = NULL;

  var $offset = NULL;

  var $total_rows = NULL;

  // Places to put attached renderings:

  var $attachment_before = '';

  var $attachment_after = '';

  // Exposed widget input

  var $exposed_data = array();

  var $exposed_input = array();

  // Exposed widget input directly from the $form_state['values'].

  var $exposed_raw_input = array();

  // Used to store views that were previously running if we recurse.

  var $old_view = array();

  // To avoid recursion in views embedded into areas.

  var $parent_views = array();

  // Is the current stored view runned as an attachment to another view.

  var $is_attachment = NULL;

  // Stores the next steps of form items to handle.

  // It's an array of stack items, which contain the form id, the type of form,

  // the view, the display and some additional arguments.

  // @see views_ui_add_form_to_stack()

  // var $stack;

  /**

   * Identifier of the current display.

   *

   * @var string

   */

  var $current_display;

  /**

   * Where the $query object will reside:

   *

   * @var views_plugin_query

   */

  var $query = NULL;

   /**

   * The current used display plugin.

   *

   * @var views_plugin_display

   */

  var $display_handler;

  /**

   * Stores all display handlers of this view.

   *

   * @var array[views_display]

   */

  var $display;

  /**

   * The current used style plugin.

   *

   * @var views_plugin_style

   */

   var $style_plugin;

  /**

   * Stored the changed options of the style plugin.

   *

   * @deprecated Better use $view->style_plugin->options

   * @var array

   */

  var $style_options;

  /**

   * Stores the current active row while rendering.

   *

   * @var int

   */

  var $row_index;

   /**

   * Allow to override the url of the current view.

   *

   * @var string

   */

  var $override_url = NULL;

  /**

   * Allow to override the path used for generated urls.

   *

   * @var string

   */

  var $override_path = NULL;

  /**

   * Allow to override the used database which is used for this query.

   */

  var $base_database = NULL;

  /**

   * Here comes a list of the possible handler which are active on this view.

   */

  /**

   * Stores the field handlers which are initialized on this view.

   * @var array[views_handler_field]

   */

  var $field;

  /**

   * Stores the argument handlers which are initialized on this view.

   * @var array[views_handler_argument]

   */

  var $argument;

  /**

   * Stores the sort handlers which are initialized on this view.

   * @var array[views_handler_sort]

   */

  var $sort;

  /**

   * Stores the filter handlers which are initialized on this view.

   * @var array[views_handler_filter]

   */

  var $filter;

  /**

   * Stores the relationship handlers which are initialized on this view.

   * @var array[views_handler_relationship]

   */

  var $relationship;

  /**

   * Stores the area handlers for the header which are initialized on this view.

   * @var array[views_handler_area]

   */

  var $header;

  /**

   * Stores the area handlers for the footer which are initialized on this view.

   * @var array[views_handler_area]

   */

  var $footer;

  /**

   * Stores the area handlers for the empty text which are initialized on this view.

   * @var array[views_handler_area]

   */

  var $empty;

  /**

   * Constructor

   */

  function __construct() {

    parent::init();

    // Make sure all of our sub objects are arrays.

    foreach ($this->db_objects() as $object) {

      $this->$object = array();

    }

  }

  /**

   * Perform automatic updates when loading or importing a view.

   *

   * Over time, some things about Views or Drupal data has changed.

   * this attempts to do some automatic updates that must happen

   * to ensure older views will at least try to work.

   */

  function update() {

    // When views are converted automatically the base_table should be renamed

    // to have a working query.

    $this->base_table = views_move_table($this->base_table);

  }

  /**

   * Returns a list of the sub-object types used by this view. These types are

   * stored on the display, and are used in the build process.

   */

  function display_objects() {

    return array('argument', 'field', 'sort', 'filter', 'relationship', 'header', 'footer', 'empty');

  }

  /**

   * Returns the complete list of dependent objects in a view, for the purpose

   * of initialization and loading/saving to/from the database.

   */

  static function db_objects() {

    return array('display');

  }

  /**

   * Set the arguments that come to this view. Usually from the URL

   * but possibly from elsewhere.

   */

  function set_arguments($args) {

    $this->args = $args;

  }

  /**

   * Change/Set the current page for the pager.

   */

  function set_current_page($page) {

    $this->current_page = $page;

    // If the pager is already initialized, pass it through to the pager.

    if (!empty($this->query->pager)) {

      return $this->query->pager->set_current_page($page);

    }

  }

  /**

   * Get the current page from the pager.

   */

  function get_current_page() {

    // If the pager is already initialized, pass it through to the pager.

    if (!empty($this->query->pager)) {

      return $this->query->pager->get_current_page();

    }

    if (isset($this->current_page)) {

      return $this->current_page;

    }

  }

  /**

   * Get the items per page from the pager.

   */

  function get_items_per_page() {

    // If the pager is already initialized, pass it through to the pager.

    if (!empty($this->query->pager)) {

      return $this->query->pager->get_items_per_page();

    }

    if (isset($this->items_per_page)) {

      return $this->items_per_page;

    }

  }

  /**

   * Set the items per page on the pager.

   */

  function set_items_per_page($items_per_page) {

    $this->items_per_page = $items_per_page;

    // If the pager is already initialized, pass it through to the pager.

    if (!empty($this->query->pager)) {

      $this->query->pager->set_items_per_page($items_per_page);

    }

  }

  /**

   * Get the pager offset from the pager.

   */

  function get_offset() {

    // If the pager is already initialized, pass it through to the pager.

    if (!empty($this->query->pager)) {

      return $this->query->pager->get_offset();

    }

    if (isset($this->offset)) {

      return $this->offset;

    }

  }

  /**

   * Set the offset on the pager.

   */

  function set_offset($offset) {

    $this->offset = $offset;

    // If the pager is already initialized, pass it through to the pager.

    if (!empty($this->query->pager)) {

      $this->query->pager->set_offset($offset);

    }

  }

  /**

   * Determine if the pager actually uses a pager.

   */

  function use_pager() {

    if (!empty($this->query->pager)) {

      return $this->query->pager->use_pager();

    }

  }

  /**

   * Whether or not AJAX should be used. If AJAX is used, paging,

   * tablesorting and exposed filters will be fetched via an AJAX call

   * rather than a page refresh.

   */

  function set_use_ajax($use_ajax) {

    $this->use_ajax = $use_ajax;

  }

  /**

   * Set the exposed filters input to an array. If unset they will be taken

   * from $_GET when the time comes.

   */

  function set_exposed_input($filters) {

    $this->exposed_input = $filters;

  }

  /**

   * Figure out what the exposed input for this view is.

   */

  function get_exposed_input() {

    if (empty($this->exposed_input)) {

      $this->exposed_input = array();

      // If filters are not overridden, store the 'remember' settings on the

      // default display. If they are, store them on this display. This way,

      // multiple displays in the same view can share the same filters and

      // remember settings.

      $display_id = ($this->display_handler->is_defaulted('filters')) ? 'default' : $this->current_display;

      // Start with remembered input via session.

      if (!empty($_SESSION['views'][$this->name][$display_id])) {

        $this->exposed_input = $_SESSION['views'][$this->name][$display_id];

      }

      // Fetch exposed input values from $_GET. Overwrite if clashing.

      foreach ($_GET as $key => $value) {

        if (!in_array($key, array('page', 'q'))) {

          $this->exposed_input[$key] = $value;

        }

      }

    }

    return $this->exposed_input;

  }

  /**

   * Set the display for this view and initialize the display handler.

   */

  function init_display($reset = FALSE) {

    // The default display is always the first one in the list.

    if (isset($this->current_display)) {

      return TRUE;

    }

    // Instantiate all displays

    foreach (array_keys($this->display) as $id) {

      // Correct for shallow cloning

      // Often we'll have a cloned view so we don't mess up each other's

      // displays, but the clone is pretty shallow and doesn't necessarily

      // clone the displays. We can tell this by looking to see if a handler

      // has already been set; if it has, but $this->current_display is not

      // set, then something is dreadfully wrong.

      if (!empty($this->display[$id]->handler)) {

        $this->display[$id] = clone $this->display[$id];

        unset($this->display[$id]->handler);

      }

      $this->display[$id]->handler = views_get_plugin('display', $this->display[$id]->display_plugin);

      if (!empty($this->display[$id]->handler)) {

        $this->display[$id]->handler->localization_keys = array($id);

        // Initialize the new display handler with data.

        $this->display[$id]->handler->init($this, $this->display[$id]);

        // If this is NOT the default display handler, let it know which is

        // since it may well utilize some data from the default.

        // This assumes that the 'default' handler is always first. It always

        // is. Make sure of it.

        if ($id != 'default') {

          $this->display[$id]->handler->default_display = &$this->display['default']->handler;

        }

      }

    }

    $this->current_display = 'default';

    $this->display_handler = &$this->display['default']->handler;

    return TRUE;

  }

  /**

   * Get the first display that is accessible to the user.

   *

   * @param $displays

   *   Either a single display id or an array of display ids.

   */

  function choose_display($displays) {

    if (!is_array($displays)) {

      return $displays;

    }

    $this->init_display();

    foreach ($displays as $display_id) {

      if ($this->display[$display_id]->handler->access()) {

        return $display_id;

      }

    }

    return 'default';

  }

  /**

   * Set the display as current.

   *

   * @param $display_id

   *   The id of the display to mark as current.

   */

  function set_display($display_id = NULL) {

    // If we have not already initialized the display, do so. But be careful.

    if (empty($this->current_display)) {

      $this->init_display();

      // If handlers were not initialized, and no argument was sent, set up

      // to the default display.

      if (empty($display_id)) {

        $display_id = 'default';

      }

    }

    $display_id = $this->choose_display($display_id);

    // If no display id sent in and one wasn't chosen above, we're finished.

    if (empty($display_id)) {

      return FALSE;

    }

    // Ensure the requested display exists.

    if (empty($this->display[$display_id])) {

      $display_id = 'default';

      if (empty($this->display[$display_id])) {

        vpr('set_display() called with invalid display id @display.', array('@display' => $display_id));

        return FALSE;

      }

    }

    // Set the current display.

    $this->current_display = $display_id;

    // Ensure requested display has a working handler.

    if (empty($this->display[$display_id]->handler)) {

      return FALSE;

    }

    // Set a shortcut

    $this->display_handler = &$this->display[$display_id]->handler;

    return TRUE;

  }

  /**

   * Find and initialize the style plugin.

   *

   * Note that arguments may have changed which style plugin we use, so

   * check the view object first, then ask the display handler.

   */

  function init_style() {

    if (isset($this->style_plugin)) {

      return is_object($this->style_plugin);

    }

    if (!isset($this->plugin_name)) {

      $this->plugin_name = $this->display_handler->get_option('style_plugin');

      $this->style_options = $this->display_handler->get_option('style_options');

    }

    $this->style_plugin = views_get_plugin('style', $this->plugin_name);

    if (empty($this->style_plugin)) {

      return FALSE;

    }

    // init the new style handler with data.

    $this->style_plugin->init($this, $this->display[$this->current_display], $this->style_options);

    return TRUE;

  }

  /**

   * Attempt to discover if the view has handlers missing relationships.

   *

   * This will try to add relationships automatically if it can, and will

   * remove the handlers if it cannot.

   */

  function fix_missing_relationships() {

    if (isset($this->relationships_fixed)) {

      return;

    }

    $this->relationships_fixed = TRUE;

    // Go through all of our handler types and test them to see if they

    // are missing relationships. Missing relationships can cause fatally

    // broken Views.

    $base_tables = array(

      $this->base_table => TRUE,

      '#global' => TRUE,

    );

    // For each relationship we have, make sure we mark the base it provides as

    // available.

    foreach ($this->display_handler->get_option('relationships') as $id => $options) {

      $options['table'] = views_move_table($options['table']);

      $data = views_fetch_data($options['table'], FALSE);

      if (isset($data[$options['field']]['relationship']['base'])) {

        $base_tables[$data[$options['field']]['relationship']['base']] = TRUE;

      }

    }

    $base_tables = array_keys($base_tables);

    $missing_base_tables = array();

    $types = views_object_types();

    foreach ($types as $key => $info) {

      foreach ($this->display_handler->get_option($info['plural']) as $id => $options) {

        $options['table'] = views_move_table($options['table']);

        $data = views_fetch_data($options['table'], FALSE);

        $valid_bases = array($options['table']);

        if (isset($data['table']['join'])) {

          $valid_bases = array_merge($valid_bases, array_keys($data['table']['join']));

        }

        // If the base table is missing, record it so we can try to fix it.

        if (!array_intersect($valid_bases, $base_tables)) {

          $missing_base_tables[$options['table']][] = array('type' => $key, 'id' => $id);

        }

      }

    }

    if (!empty($missing_base_tables)) {

      // This will change handlers, so make sure any existing handlers get

      // tossed.

      $this->display_handler->handlers = array();

      $this->relationships_changed = TRUE;

      $this->changed = TRUE;

      // Try to fix it.

      foreach ($missing_base_tables as $table => $handlers) {

        $data = views_fetch_data($table);

        $relationship = NULL;

        // Does the missing base table have a default relationship we can

        // throw in?

        if (isset($data['table']['default_relationship'][$this->base_table])) {

          // Create the relationship.

          $info = $data['table']['default_relationship'][$this->base_table];

          $relationship_options = isset($info['options']) ? $info['options'] : array();

          $relationship = $this->add_item($this->current_display, 'relationship', $info['table'], $info['field'], $relationship_options);

        }

        foreach ($handlers as $handler) {

          $options = $this->display_handler->get_option($types[$handler['type']]['plural']);

          if ($relationship) {

            $options[$handler['id']]['relationship'] = $relationship;

          }

          else {

            unset($options[$handler['id']]);

          }

          $this->display_handler->set_option($types[$handler['type']]['plural'], $options);

        }

      }

    }

  }

  /**

   * Acquire and attach all of the handlers.

   */

  function init_handlers() {

    if (empty($this->inited)) {

      $this->fix_missing_relationships();

      foreach (views_object_types() as $key => $info) {

        $this->_init_handler($key, $info);

      }

      $this->inited = TRUE;

    }

  }

  /**

   * Initialize the pager

   *

   * Like style initialization, pager initialization is held until late

   * to allow for overrides.

   */

  function init_pager() {

    if (empty($this->query->pager)) {

      // If the query doesn't exist, initialize it.

      if (empty($this->query)) {

        $this->init_query();

      }

      $this->query->pager = $this->display_handler->get_plugin('pager');

      if ($this->query->pager->use_pager()) {

        $this->query->pager->set_current_page($this->current_page);

      }

      // These overrides may have been set earlier via $view->set_*

      // functions.

      if (isset($this->items_per_page)) {

        $this->query->pager->set_items_per_page($this->items_per_page);

      }

      if (isset($this->offset)) {

        $this->query->pager->set_offset($this->offset);

      }

    }

  }

  /**

   * Create a list of base tables eligible for this view. Used primarily

   * for the UI. Display must be already initialized.

   */

  function get_base_tables() {

    $base_tables = array(

      $this->base_table => TRUE,

      '#global' => TRUE,

    );

    foreach ($this->display_handler->get_handlers('relationship') as $handler) {

      $base_tables[$handler->definition['base']] = TRUE;

    }

    return $base_tables;

  }

  /**

   * Run the pre_query() on all active handlers.

   */

  function _pre_query() {

    foreach (views_object_types() as $key => $info) {

      $handlers = &$this->$key;

      $position = 0;

      foreach ($handlers as $id => $handler) {

        $handlers[$id]->position = $position;

        $handlers[$id]->pre_query();

        $position++;

      }

    }

  }

  /**

   * Run the post_execute() on all active handlers.

   */

  function _post_execute() {

    foreach (views_object_types() as $key => $info) {

      $handlers = &$this->$key;

      foreach ($handlers as $id => $handler) {

        $handlers[$id]->post_execute($this->result);

      }

    }

  }

  /**

   * Attach all of the handlers for each type.

   *

   * @param $key

   *   One of 'argument', 'field', 'sort', 'filter', 'relationship'

   * @param $info

   *   The $info from views_object_types for this object.

   */

  function _init_handler($key, $info) {

    // Load the requested items from the display onto the object.

    $this->$key = &$this->display_handler->get_handlers($key);

    // This reference deals with difficult PHP indirection.

    $handlers = &$this->$key;

    // Run through and test for accessibility.

    foreach ($handlers as $id => $handler) {

      if (!$handler->access()) {

        unset($handlers[$id]);

      }

    }

  }

  /**

   * Build all the arguments.

   */

  function _build_arguments() {

    // Initially, we want to build sorts and fields. This can change, though,

    // if we get a summary view.

    if (empty($this->argument)) {

      return TRUE;

    }

    // build arguments.

    $position = -1;

    // Create a title for use in the breadcrumb trail.

    $title = $this->display_handler->get_option('title');

    $this->build_info['breadcrumb'] = array();

    $breadcrumb_args = array();

    $substitutions = array();

    $status = TRUE;

    // Iterate through each argument and process.

    foreach ($this->argument as $id => $arg) {

      $position++;

      $argument = &$this->argument[$id];

      if ($argument->broken()) {

        continue;

      }

      $argument->set_relationship();

      $arg = isset($this->args[$position]) ? $this->args[$position] : NULL;

      $argument->position = $position;

      if (isset($arg) || $argument->has_default_argument()) {

        if (!isset($arg)) {

          $arg = $argument->get_default_argument();

          // make sure default args get put back.

          if (isset($arg)) {

            $this->args[$position] = $arg;

          }

        }

        // Set the argument, which will also validate that the argument can be set.

        if (!$argument->set_argument($arg)) {

          $status = $argument->validate_fail($arg);

          break;

        }

        if ($argument->is_exception()) {

          $arg_title = $argument->exception_title();

        }

        else {

          $arg_title = $argument->get_title();

          $argument->query($this->display_handler->use_group_by());

        }

        // Add this argument's substitution

        $substitutions['%' . ($position + 1)] = $arg_title;

        $substitutions['!' . ($position + 1)] = strip_tags(decode_entities($arg));

        // Since we're really generating the breadcrumb for the item above us,

        // check the default action of this argument.

        if ($this->display_handler->uses_breadcrumb() && $argument->uses_breadcrumb()) {

          $path = $this->get_url($breadcrumb_args);

          if (strpos($path, '%') === FALSE) {

            if (!empty($argument->options['breadcrumb_enable']) && !empty($argument->options['breadcrumb'])) {

              $breadcrumb = $argument->options['breadcrumb'];

            }

            else {

              $breadcrumb = $title;

            }

            $this->build_info['breadcrumb'][$path] = str_replace(array_keys($substitutions), $substitutions, $breadcrumb);

          }

        }

        // Allow the argument to muck with this breadcrumb.

        $argument->set_breadcrumb($this->build_info['breadcrumb']);

        // Test to see if we should use this argument's title

        if (!empty($argument->options['title_enable']) && !empty($argument->options['title'])) {

          $title = $argument->options['title'];

        }

        $breadcrumb_args[] = $arg;

      }

      else {

        // determine default condition and handle.

        $status = $argument->default_action();

        break;

      }

      // Be safe with references and loops:

      unset($argument);

    }

    // set the title in the build info.

    if (!empty($title)) {

      $this->build_info['title'] = $title;

    }

    // Store the arguments for later use.

    $this->build_info['substitutions'] = $substitutions;

    return $status;

  }

  /**

   * Do some common building initialization.

   */

  function init_query() {

    if (!empty($this->query)) {

      $class = get_class($this->query);

      if ($class && $class != 'stdClass') {

        // return if query is already initialized.

        return TRUE;

      }

    }

    // Create and initialize the query object.

    $views_data = views_fetch_data($this->base_table);

    $this->base_field = !empty($views_data['table']['base']['field']) ? $views_data['table']['base']['field'] : '';

    if (!empty($views_data['table']['base']['database'])) {

      $this->base_database = $views_data['table']['base']['database'];

    }

    // Load the options.

    $query_options = $this->display_handler->get_option('query');

    // Create and initialize the query object.

    $plugin = !empty($views_data['table']['base']['query class']) ? $views_data['table']['base']['query class'] : 'views_query';

    $this->query = views_get_plugin('query', $plugin);

    if (empty($this->query)) {

      return FALSE;

    }

    $this->query->init($this->base_table, $this->base_field, $query_options['options']);

    return TRUE;

  }

  /**

   * Build the query for the view.

   */

  function build($display_id = NULL) {

    if (!empty($this->built)) {

      return;

    }

    if (empty($this->current_display) || $display_id) {

      if (!$this->set_display($display_id)) {

        return FALSE;

      }

    }

    // Let modules modify the view just prior to building it.

    foreach (module_implements('views_pre_build') as $module) {

      $function = $module . '_views_pre_build';

      $function($this);

    }

    // Attempt to load from cache.

    // @todo Load a build_info from cache.

    $start = microtime(TRUE);

    // If that fails, let's build!

    $this->build_info = array(

      'query' => '',

      'count_query' => '',

      'query_args' => array(),

    );

    $this->init_query();

    // Call a module hook and see if it wants to present us with a

    // pre-built query or instruct us not to build the query for

    // some reason.

    // @todo: Implement this. Use the same mechanism Panels uses.

    // Run through our handlers and ensure they have necessary information.

    $this->init_handlers();

    // Let the handlers interact with each other if they really want.

    $this->_pre_query();

    if ($this->display_handler->uses_exposed()) {

      $exposed_form = $this->display_handler->get_plugin('exposed_form');

      // (1) Record the errors before rendering the exposed form widgets.

      $errors_before = form_set_error();

      $this->exposed_widgets = $exposed_form->render_exposed_form();

      // (2) Record the errors after rendering the exposed form widgets.

      $errors_after = form_set_error();

      // Find out if the validation of any of the elements in the exposed form

      // has failed by comparing (1) and (2) above. Don't mess with the view

      // otherwise.

      $exposed_errors = count($errors_after) > count($errors_before);

      if ($exposed_errors || !empty($this->build_info['abort'])) {

        $this->built = TRUE;

        // Don't execute the query, but rendering will still be executed to display the empty text.

        $this->executed = TRUE;

        return empty($this->build_info['fail']);

      }

    }

    // Build all the relationships first thing.

    $this->_build('relationship');

    // Set the filtering groups.

    if (!empty($this->filter)) {

      $filter_groups = $this->display_handler->get_option('filter_groups');

      if ($filter_groups) {

        $this->query->set_group_operator($filter_groups['operator']);

        foreach($filter_groups['groups'] as $id => $operator) {

          $this->query->set_where_group($operator, $id);

        }

      }

    }

    // Build all the filters.

    $this->_build('filter');

    $this->build_sort = TRUE;

    // Arguments can, in fact, cause this whole thing to abort.

    if (!$this->_build_arguments()) {

      $this->build_time = microtime(TRUE) - $start;

      $this->attach_displays();

      return $this->built;

    }

    // Initialize the style; arguments may have changed which style we use,

    // so waiting as long as possible is important. But we need to know

    // about the style when we go to build fields.

    if (!$this->init_style()) {

      $this->build_info['fail'] = TRUE;

      return FALSE;

    }

    if ($this->style_plugin->uses_fields()) {

      $this->_build('field');

    }

    // Build our sort criteria if we were instructed to do so.

    if (!empty($this->build_sort)) {

      // Allow the style handler to deal with sorting.

      if ($this->style_plugin->build_sort()) {

        $this->_build('sort');

      }

      // allow the plugin to build second sorts as well.

      $this->style_plugin->build_sort_post();

    }

    // Allow area handlers to affect the query.

    $this->_build('header');

    $this->_build('footer');

    $this->_build('empty');

    // Allow display handler to affect the query:

    $this->display_handler->query($this->display_handler->use_group_by());

    // Allow style handler to affect the query:

    $this->style_plugin->query($this->display_handler->use_group_by());

    // Allow exposed form to affect the query:

    if (isset($exposed_form)) {

      $exposed_form->query();

    }

    if (variable_get('views_sql_signature', FALSE)) {

      $this->query->add_signature($this);

    }

    // Let modules modify the query just prior to finalizing it.

    $this->query->alter($this);

    // Only build the query if we weren't interrupted.

    if (empty($this->built)) {

      // Build the necessary info to execute the query.

      $this->query->build($this);

    }

    $this->built = TRUE;

    $this->build_time = microtime(TRUE) - $start;

    // Attach displays

    $this->attach_displays();

    // Let modules modify the view just after building it.

    foreach (module_implements('views_post_build') as $module) {

      $function = $module . '_views_post_build';

      $function($this);

    }

    return TRUE;

  }

  /**

   * Internal method to build an individual set of handlers.

   *

   * @param string $key

   *    The type of handlers (filter etc.) which should be iterated over to

   *    build the relationship and query information.

   */

  function _build($key) {

    $handlers = &$this->$key;

    foreach ($handlers as $id => $data) {

      if (!empty($handlers[$id]) && is_object($handlers[$id])) {

        $multiple_exposed_input = array(0 => NULL);

        if ($handlers[$id]->multiple_exposed_input()) {

          $multiple_exposed_input = $handlers[$id]->group_multiple_exposed_input($this->exposed_data);

        }

        foreach ($multiple_exposed_input as $group_id) {

          // Give this handler access to the exposed filter input.

          if (!empty($this->exposed_data)) {

            $converted = FALSE;

            if ($handlers[$id]->is_a_group()) {

              $converted = $handlers[$id]->convert_exposed_input($this->exposed_data, $group_id);

              $handlers[$id]->store_group_input($this->exposed_data, $converted);

              if (!$converted) {

                continue;

              }

            }

            $rc = $handlers[$id]->accept_exposed_input($this->exposed_data);

            $handlers[$id]->store_exposed_input($this->exposed_data, $rc);

            if (!$rc) {

              continue;

            }

          }

          $handlers[$id]->set_relationship();

          $handlers[$id]->query($this->display_handler->use_group_by());

        }

      }

    }

  }

  /**

   * Execute the view's query.

   *

   * @param string $display_id

   *   The machine name of the display, which should be executed.

   *

   * @return bool

   *   Return whether the executing was successful, for example an argument

   *   could stop the process.

   */

  function execute($display_id = NULL) {

    if (empty($this->built)) {