Multisite: Add `lang_id` support to `WP_Site_Query`.

Sites can now be queried by `lang_id`, `lang__in`, and `lang__not_in`.

Props ocean90.
Fixes #40196.

Built from https://develop.svn.wordpress.org/trunk@40340


git-svn-id: http://core.svn.wordpress.org/trunk@40247 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/class-wp-site-query.php

@@ -99,6 +99,7 @@ class WP_Site_Query {
 	 * Sets up the site query, based on the query vars passed.
 	 *
 	 * @since 4.6.0
+	 * @since 4.8.0 Introduced the 'lang_id', 'lang__in', and 'lang__not_in' parameters.
 	 * @access public
 	 *
 	 * @param string|array $query {
@@ -138,6 +139,9 @@ class WP_Site_Query {
 	 *     @type int          $mature            Limit results to mature sites. Accepts '1' or '0'. Default empty.
 	 *     @type int          $spam              Limit results to spam sites. Accepts '1' or '0'. Default empty.
 	 *     @type int          $deleted           Limit results to deleted sites. Accepts '1' or '0'. Default empty.
+	 *     @type int          $lang_id           Limit results to a language ID. Default empty.
+	 *     @type array        $lang__in          Array of language IDs to include affiliated sites for. Default empty.
+	 *     @type array        $lang__not_in      Array of language IDs to exclude affiliated sites for. Default empty.
 	 *     @type string       $search            Search term(s) to retrieve matching sites for. Default empty.
 	 *     @type array        $search_columns    Array of column names to be searched. Accepts 'domain' and 'path'.
 	 *                                           Default empty array.
@@ -169,6 +173,9 @@ class WP_Site_Query {
 			'mature'            => null,
 			'spam'              => null,
 			'deleted'           => null,
+			'lang_id'           => null,
+			'lang__in'          => '',
+			'lang__not_in'      => '',
 			'search'            => '',
 			'search_columns'    => array(),
 			'count'             => false,
@@ -471,6 +478,21 @@ class WP_Site_Query {
 			$this->sql_clauses['where']['public'] = $wpdb->prepare( "public = %d ", $public );
 		}
 
+		if ( is_numeric( $this->query_vars['lang_id'] ) ) {
+			$lang_id = absint( $this->query_vars['lang_id'] );
+			$this->sql_clauses['where']['lang_id'] = $wpdb->prepare( "lang_id = %d ", $lang_id );
+		}
+
+		// Parse site language IDs for an IN clause.
+		if ( ! empty( $this->query_vars['lang__in'] ) ) {
+			$this->sql_clauses['where']['lang__in'] = 'lang_id IN ( ' . implode( ',', wp_parse_id_list( $this->query_vars['lang__in'] ) ) . ' )';
+		}
+
+		// Parse site language IDs for a NOT IN clause.
+		if ( ! empty( $this->query_vars['lang__not_in'] ) ) {
+			$this->sql_clauses['where']['lang__not_in'] = 'lang_id NOT IN ( ' . implode( ',', wp_parse_id_list( $this->query_vars['lang__not_in'] ) ) . ' )';
+		}
+
 		// Falsey search strings are ignored.
 		if ( strlen( $this->query_vars['search'] ) ) {
 			$search_columns = array();

wp-includes/ms-blogs.php

@@ -573,6 +573,7 @@ function update_site_cache( $sites ) {
  * Retrieves a list of sites matching requested arguments.
  *
  * @since 4.6.0
+ * @since 4.8.0 Introduced the 'lang_id', 'lang__in', and 'lang__not_in' parameters.
  *
  * @see WP_Site_Query::parse_query()
  *
@@ -613,6 +614,9 @@ function update_site_cache( $sites ) {
  *     @type int          $mature            Limit results to mature sites. Accepts '1' or '0'. Default empty.
  *     @type int          $spam              Limit results to spam sites. Accepts '1' or '0'. Default empty.
  *     @type int          $deleted           Limit results to deleted sites. Accepts '1' or '0'. Default empty.
+ *     @type int          $lang_id           Limit results to a language ID. Default empty.
+ *     @type array        $lang__in          Array of language IDs to include affiliated sites for. Default empty.
+ *     @type array        $lang__not_in      Array of language IDs to exclude affiliated sites for. Default empty.
  *     @type string       $search            Search term(s) to retrieve matching sites for. Default empty.
  *     @type array        $search_columns    Array of column names to be searched. Accepts 'domain' and 'path'.
  *                                           Default empty array.

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.8-alpha-40339';
+$wp_version = '4.8-alpha-40340';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.