Introduce `wp_using_ext_object_cache()` - mimic `wp_suspend_cache_invalidation()` and discourage direct access to `$_wp_using_ext_object_cache`, cleaning up importing of globals in functions and provides function to modify that global. Loads the packaged object cache when an external cache hasn't been loaded or doesn't contain `wp_cache_init()`.

Fixes #21401.


Built from https://develop.svn.wordpress.org/trunk@25289


git-svn-id: http://core.svn.wordpress.org/trunk@25253 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-cron.php

@@ -28,10 +28,10 @@ if ( !defined('ABSPATH') ) {
 
 // Uncached doing_cron transient fetch
 function _get_cron_lock() {
-	global $_wp_using_ext_object_cache, $wpdb;
+	global $wpdb;
 
 	$value = 0;
-	if ( $_wp_using_ext_object_cache ) {
+	if ( wp_using_ext_object_cache() ) {
 		// Skip local cache and force refetch of doing_cron transient in case
 		// another processs updated the cache
 		$value = wp_cache_get( 'doing_cron', 'transient', true );

wp-includes/load.php

@@ -369,6 +369,24 @@ function wp_set_wpdb_vars() {
 	}
 }
 
+/**
+ * Access/Modify private global variable $_wp_using_ext_object_cache
+ *
+ * Toggle $_wp_using_ext_object_cache on and off without directly touching global
+ *
+ * @since 3.7.0
+ *
+ * @param bool $using Whether external object cache is being used
+ * @return bool The current 'using' setting
+ */
+function wp_using_ext_object_cache( $using = null ) {
+	global $_wp_using_ext_object_cache;
+	$current_using = $_wp_using_ext_object_cache;
+	if ( null !== $using )
+		$_wp_using_ext_object_cache = $using;
+	return $current_using;
+}
+
 /**
  * Starts the WordPress object cache.
  *
@@ -379,31 +397,33 @@ function wp_set_wpdb_vars() {
  * @since 3.0.0
  */
 function wp_start_object_cache() {
-	global $_wp_using_ext_object_cache, $blog_id;
+	global $blog_id;
 
 	$first_init = false;
  	if ( ! function_exists( 'wp_cache_init' ) ) {
 		if ( file_exists( WP_CONTENT_DIR . '/object-cache.php' ) ) {
 			require_once ( WP_CONTENT_DIR . '/object-cache.php' );
-			$_wp_using_ext_object_cache = true;
+			if ( function_exists( 'wp_cache_init' ) )
-		} else {
+				wp_using_ext_object_cache( true );
-			require_once ( ABSPATH . WPINC . '/cache.php' );
-			$_wp_using_ext_object_cache = false;
 		}
+
 		$first_init = true;
-	} else if ( !$_wp_using_ext_object_cache && file_exists( WP_CONTENT_DIR . '/object-cache.php' ) ) {
+	} else if ( ! wp_using_ext_object_cache() && file_exists( WP_CONTENT_DIR . '/object-cache.php' ) ) {
 		// Sometimes advanced-cache.php can load object-cache.php before it is loaded here.
 		// This breaks the function_exists check above and can result in $_wp_using_ext_object_cache
 		// being set incorrectly. Double check if an external cache exists.
-		$_wp_using_ext_object_cache = true;
+		wp_using_ext_object_cache( true );
 	}
 
+	if ( ! wp_using_ext_object_cache() )
+		require_once ( ABSPATH . WPINC . '/cache.php' );
+
 	// If cache supports reset, reset instead of init if already initialized.
 	// Reset signals to the cache that global IDs have changed and it may need to update keys
 	// and cleanup caches.
 	if ( ! $first_init && function_exists( 'wp_cache_switch_to_blog' ) )
 		wp_cache_switch_to_blog( $blog_id );
-	else
+	elseif ( function_exists( 'wp_cache_init' ) )
 		wp_cache_init();
 
 	if ( function_exists( 'wp_cache_add_global_groups' ) ) {

wp-includes/nav-menu.php

@@ -476,8 +476,6 @@ function _is_valid_nav_menu_item( $item ) {
  * @return mixed $items array of menu items, else false.
  */
 function wp_get_nav_menu_items( $menu, $args = array() ) {
-	global $_wp_using_ext_object_cache;
-
 	$menu = wp_get_nav_menu_object( $menu );
 
 	if ( ! $menu )
@@ -504,7 +502,7 @@ function wp_get_nav_menu_items( $menu, $args = array() ) {
 		return false;
 
 	// Get all posts and terms at once to prime the caches
-	if ( empty( $fetched[$menu->term_id] ) || $_wp_using_ext_object_cache ) {
+	if ( empty( $fetched[$menu->term_id] ) || wp_using_ext_object_cache() ) {
 		$fetched[$menu->term_id] = true;
 		$posts = array();
 		$terms = array();

wp-includes/option.php

@@ -165,9 +165,9 @@ function wp_load_alloptions() {
  * @param int $site_id Optional site ID for which to query the options. Defaults to the current site.
  */
 function wp_load_core_site_options( $site_id = null ) {
-	global $wpdb, $_wp_using_ext_object_cache;
+	global $wpdb;
 
-	if ( !is_multisite() || $_wp_using_ext_object_cache || defined( 'WP_INSTALLING' ) )
+	if ( !is_multisite() || wp_using_ext_object_cache() || defined( 'WP_INSTALLING' ) )
 		return;
 
 	if ( empty($site_id) )
@@ -404,11 +404,9 @@ function delete_option( $option ) {
  * @return bool true if successful, false otherwise
  */
 function delete_transient( $transient ) {
-	global $_wp_using_ext_object_cache;
-
 	do_action( 'delete_transient_' . $transient, $transient );
 
-	if ( $_wp_using_ext_object_cache ) {
+	if ( wp_using_ext_object_cache() ) {
 		$result = wp_cache_delete( $transient, 'transient' );
 	} else {
 		$option_timeout = '_transient_timeout_' . $transient;
@@ -443,13 +441,11 @@ function delete_transient( $transient ) {
  * @return mixed Value of transient
  */
 function get_transient( $transient ) {
-	global $_wp_using_ext_object_cache;
-
 	$pre = apply_filters( 'pre_transient_' . $transient, false );
 	if ( false !== $pre )
 		return $pre;
 
-	if ( $_wp_using_ext_object_cache ) {
+	if ( wp_using_ext_object_cache() ) {
 		$value = wp_cache_get( $transient, 'transient' );
 	} else {
 		$transient_option = '_transient_' . $transient;
@@ -493,11 +489,9 @@ function get_transient( $transient ) {
  * @return bool False if value was not set and true if value was set.
  */
 function set_transient( $transient, $value, $expiration = 0 ) {
-	global $_wp_using_ext_object_cache;
-
 	$value = apply_filters( 'pre_set_transient_' . $transient, $value );
 
-	if ( $_wp_using_ext_object_cache ) {
+	if ( wp_using_ext_object_cache() ) {
 		$result = wp_cache_set( $transient, $value, 'transient', $expiration );
 	} else {
 		$transient_timeout = '_transient_timeout_' . $transient;
@@ -970,10 +964,8 @@ function update_site_option( $option, $value ) {
  * @return bool True if successful, false otherwise
  */
 function delete_site_transient( $transient ) {
-	global $_wp_using_ext_object_cache;
-
 	do_action( 'delete_site_transient_' . $transient, $transient );
-	if ( $_wp_using_ext_object_cache ) {
+	if ( wp_using_ext_object_cache() ) {
 		$result = wp_cache_delete( $transient, 'site-transient' );
 	} else {
 		$option_timeout = '_site_transient_timeout_' . $transient;
@@ -1008,13 +1000,11 @@ function delete_site_transient( $transient ) {
  * @return mixed Value of transient
  */
 function get_site_transient( $transient ) {
-	global $_wp_using_ext_object_cache;
-
 	$pre = apply_filters( 'pre_site_transient_' . $transient, false );
 	if ( false !== $pre )
 		return $pre;
 
-	if ( $_wp_using_ext_object_cache ) {
+	if ( wp_using_ext_object_cache() ) {
 		$value = wp_cache_get( $transient, 'site-transient' );
 	} else {
 		// Core transients that do not have a timeout. Listed here so querying timeouts can be avoided.
@@ -1058,11 +1048,9 @@ function get_site_transient( $transient ) {
  * @return bool False if value was not set and true if value was set.
  */
 function set_site_transient( $transient, $value, $expiration = 0 ) {
-	global $_wp_using_ext_object_cache;
-
 	$value = apply_filters( 'pre_set_site_transient_' . $transient, $value );
 
-	if ( $_wp_using_ext_object_cache ) {
+	if ( wp_using_ext_object_cache() ) {
 		$result = wp_cache_set( $transient, $value, 'site-transient', $expiration );
 	} else {
 		$transient_timeout = '_site_transient_timeout_' . $transient;

wp-includes/query.php

@@ -1946,7 +1946,7 @@ class WP_Query {
 	 * @return array List of posts.
 	 */
 	function get_posts() {
-		global $wpdb, $user_ID, $_wp_using_ext_object_cache;
+		global $wpdb, $user_ID;
 
 		$this->parse_query();
 
@@ -1996,7 +1996,7 @@ class WP_Query {
 			$q['suppress_filters'] = false;
 
 		if ( !isset($q['cache_results']) ) {
-			if ( $_wp_using_ext_object_cache )
+			if ( wp_using_ext_object_cache() )
 				$q['cache_results'] = false;
 			else
 				$q['cache_results'] = true;