Multisite: Introduce `get_network()`.

Given a network ID or network object, `get_network()` retrieves network data in the same vein as `get_site()` or `get_post()`. This will allow for clean retrieval of networks from a primed cache when `WP_Network_Query` is implemented.

Props flixos90.
See #32504.

Built from https://develop.svn.wordpress.org/trunk@37893


git-svn-id: http://core.svn.wordpress.org/trunk@37834 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/ms-blogs.php

@@ -1071,6 +1071,49 @@ function get_last_updated( $deprecated = '', $start = 0, $quantity = 40 ) {
 	return $wpdb->get_results( $wpdb->prepare("SELECT blog_id, domain, path FROM $wpdb->blogs WHERE site_id = %d AND public = '1' AND archived = '0' AND mature = '0' AND spam = '0' AND deleted = '0' AND last_updated != '0000-00-00 00:00:00' ORDER BY last_updated DESC limit %d, %d", $wpdb->siteid, $start, $quantity ) , ARRAY_A );
 }
 
+/**
+ * Retrieves network data given a network ID or network object.
+ *
+ * Network data will be cached and returned after being passed through a filter.
+ * If the provided network is empty, the current network global will be used.
+ *
+ * @since 4.6.0
+ *
+ * @global WP_Network $current_site
+ *
+ * @param WP_Network|int|null $network Network to retrieve.
+ * @return WP_Network|null The network object or null if not found.
+ */
+function get_network( &$network = null ) {
+	global $current_site;
+	if ( empty( $network ) && isset( $current_site ) ) {
+		$network = $current_site;
+	}
+
+	if ( $network instanceof WP_Network ) {
+		$_network = $network;
+	} elseif ( is_object( $network ) ) {
+		$_network = new WP_Network( $network );
+	} else {
+		$_network = WP_Network::get_instance( $network );
+	}
+
+	if ( ! $_network ) {
+		return null;
+	}
+
+	/**
+	 * Fires after a network is retrieved.
+	 *
+	 * @since 4.6.0
+	 *
+	 * @param WP_Network $_network Network data.
+	 */
+	$_network = apply_filters( 'get_network', $_network );
+
+	return $_network;
+}
+
 /**
  * Handler for updating the blog date when a post is published or an already published post is changed.
  *

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.6-alpha-37892';
+$wp_version = '4.6-alpha-37893';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.