Refactoring of get_pages()

gistfile1.txt

/**
 * Retrieve a list of pages.
 *
 * The defaults that can be overridden are the following: 'child_of',
 * 'sort_order', 'sort_column', 'post_title', 'hierarchical', 'exclude',
 * 'include', 'meta_key', 'meta_value','authors', 'number', and 'offset'.
 *
 * @since 1.5.0
 * @uses $wpdb
 *
 * @param mixed $args Optional. Array or string of options that overrides defaults.
 * @return array List of pages matching defaults or $args
 */
function &get_pages($args = '') {

	$defaults = array(
		'child_of' => 0, 'sort_order' => 'ASC',
		'sort_column' => 'post_title', 'hierarchical' => 1,
		'exclude' => array(), 'include' => array(),
		'meta_key' => '', 'meta_value' => '',
		'authors' => '', 'parent' => '', 'exclude_tree' => '',
		'number' => '', 'offset' => 0,
		'post_type' => 'page', 'post_status' => 'publish',
	);

	$r = wp_parse_args( $args, $defaults );
  extract( $r, EXTR_SKIP );

  //ignore child_of, parent, exclude, meta_key, and meta_value params if using include
	if ( !empty($include) ) {
		$child_of = 0; 
		$parent = '';
		$exclude = '';
		$meta_key = '';
		$meta_value = '';
		$hierarchical = false;
	}
  
	// Make sure the post type is hierarchical
  // TODO extract this to something like is_a_hierarchical_post_type( $post_type )
	$hierarchical_post_types = get_post_types( array( 'hierarchical' => true ) );
	if ( !in_array( $post_type, $hierarchical_post_types ) )
		return false;

	$sort_order = strtoupper( $sort_order );
	if ( empty( $sort_order ) && ! in_array( $sort_order, array( 'ASC', 'DESC' ) ) )
		$sort_order = 'ASC';

  // Check whether we have cached the results of the same query
	$cache = array();
	$key = md5( serialize( compact(array_keys($defaults)) ) );
	if ( $cache = wp_cache_get( 'get_pages', 'posts' ) ) {
		if ( is_array( $cache ) && isset( $cache[ $key ] ) ) {
			$pages = apply_filters( 'get_pages', $cache[ $key ], $r );
			return $pages;
		}
	}

	if ( ! is_array( $cache ) )
		$cache = array();

  // TODO Break up the collection of ids_of_requested_pages_to_include from the creation of the SQL string based on it.

  // TODO Rename $post_authors to $requested_authors
	if ( ! empty( $authors ) ) {
		$post_authors = preg_split( '/[\s,]+/',$authors );

		if ( ! empty( $post_authors ) ) {
			foreach ( $post_authors as $post_author ) {
				//Do we have an author id or an author login?
				if ( 0 == intval( $post_author ) ) {
					$post_author = get_user_by( 'login', $post_author );
					if ( empty( $post_author ) || empty( $post_author->ID ) )
						continue;
					$author_ids[] = $post_author->ID;
				} else {
          $author_ids[] = $post_author;
        }
      }
		}
    $r['author'] = join( ',', $author_ids );
	}

  // get_pages() API supports both post_author and author for sorting, and WP_Query only supports the version without the post_ prefix
	// TODO get_pages had this additional sorting field. Figure out what to do about this one: $allowed_keys = array( 'modified_gmt', 'post_modified_gmt' );
  $sort_column = str_replace( array( 'post_', ',' ), array( '', ' ' ), $sort_column );


  // Do the translations
  /* get_pages   => WP_Query mapping:
   * sort_order  => order
   * sort_column => orderby
   * authors     => author / author_name
   * number      => posts_per_page
   * include     => post__in
   * exclude     => post__not_in
   * 
   */

	if ( ! empty( $r['number'] ) && empty( $r['posts_per_page'] ) )
		$r['posts_per_page'] = $r['number'];
	if ( ! empty( $include ) ) {
		$incposts = wp_parse_id_list( $include );
		$r['posts_per_page'] = count($incposts);  // only the number of posts included
		$r['post__in'] = $incposts;
	} elseif ( ! empty( $exclude ) )
		$r['post__not_in'] = wp_parse_id_list( $exclude );

  if ( ! empty( $sort_order ) )
    $r['order'] = $sort_order;

  if ( ! empty( $sort_column ) )
    $r['orderby'] = $sort_column;

	$r['ignore_sticky_posts'] = true;
	$r['no_found_rows'] = true;

  $get_pages = new WP_Query;
	$pages = $get_pages->query( $r );

	if ( empty($pages) ) {
		$pages = apply_filters('get_pages', array(), $r);
		return $pages;
	}

	// Update cache.
	update_page_cache($pages);

	if ( $child_of || $hierarchical )
		$pages = & get_page_children($child_of, $pages);

	if ( !empty($exclude_tree) ) {
		$exclude = (int) $exclude_tree;
		$children = get_page_children($exclude, $pages);
		$excludes = array();
		foreach ( $children as $child )
			$excludes[] = $child->ID;
		$excludes[] = $exclude;
		$num_pages = count($pages);
		for ( $i = 0; $i < $num_pages; $i++ ) {
			if ( in_array($pages[$i]->ID, $excludes) )
				unset($pages[$i]);
		}
	}

  // TODO rename $key to unique_id_for_a_given_set_of_params
	$cache[ $key ] = $pages;
	wp_cache_set( 'get_pages', $cache, 'posts' );

	$pages = apply_filters('get_pages', $pages, $r);

	return $pages;
}