Ticket #22661: 22661-cache_via_filters-ext_object_filter.diff

src/wp-includes/cache.php

@@ -22 +22 @@
  * @return bool False if cache key and group already exist, true on success
  */
 function wp_cache_add( $key, $data, $group = '', $expire = 0 ) {
+        // Try to add cache via hooked up method(s)
+        $result = apply_filters('wp_cache_add', null, $key, $data, $group, (int) $expire);
+        if (null !== $result) {
+                return $result;
+        }
+
+        // Fall back on internal cache if nothing has been done yet
         global $wp_object_cache;
 
         return $wp_object_cache->add( $key, $data, $group, (int) $expire );
@@ -40 +47 @@
  * @return bool Always returns True
  */
 function wp_cache_close() {
+        $result = apply_filters('wp_cache_close', null);
+        if ( null !== $result ) {
+                return $result;
+        }
+
         return true;
 }
 
@@ -56 +68 @@
  * @return false|int False on failure, the item's new value on success.
  */
 function wp_cache_decr( $key, $offset = 1, $group = '' ) {
+        $result = apply_filters('wp_cache_decr', null, $key, $offset, $group);
+        if (null !== $result) {
+                return $result;
+        }
+
         global $wp_object_cache;
 
         return $wp_object_cache->decr( $key, $offset, $group );
@@ -73 +90 @@
  * @return bool True on successful removal, false on failure
  */
 function wp_cache_delete($key, $group = '') {
+        $result = apply_filters('wp_cache_delete', null, $key, $group);
+        if (null !== $result) {
+                return $result;
+        }
+
         global $wp_object_cache;
 
         return $wp_object_cache->delete($key, $group);
@@ -88 +110 @@
  * @return bool False on failure, true on success
  */
 function wp_cache_flush() {
+        $result = apply_filters('wp_cache_flush', null);
+        if ( null !== $result ) {
+                return $result;
+        }
+
         global $wp_object_cache;
 
         return $wp_object_cache->flush();
@@ -108 +135 @@
  *              contents on success
  */
 function wp_cache_get( $key, $group = '', $force = false, &$found = null ) {
+        $result = apply_filters('wp_cache_get', null, $key, $group, $force);
+        if (null !== $result) {
+                $found = true;
+                return $result;
+        }
+
         global $wp_object_cache;
 
         return $wp_object_cache->get( $key, $group, $force, $found );
@@ -126 +159 @@
  * @return false|int False on failure, the item's new value on success.
  */
 function wp_cache_incr( $key, $offset = 1, $group = '' ) {
+        $result = apply_filters('wp_cache_inc', null, $key, $offset, $group);
+        if (null !== $result) {
+                return $result;
+        }
+
         global $wp_object_cache;
 
         return $wp_object_cache->incr( $key, $offset, $group );
@@ -138 +176 @@
  * @global WP_Object_Cache $wp_object_cache WordPress Object Cache
  */
 function wp_cache_init() {
+        do_action('wp_cache_init');
+
+        // Calling init on attached cache objects, if one or more loads; we have external cache
+        $result = apply_filters( 'wp_object_cache', false );
+        if ( true === $result ) {
+                wp_using_ext_object_cache( true );
+        }
+
+        // Create cache object in case of failing cache implementation or filters not being applied
         $GLOBALS['wp_object_cache'] = new WP_Object_Cache();
+
+        /*
+         * Because of the filter implementation this would not be called on 'first-run',
+         * and it would make sense to switch to the current blog on initialize
+         */
+        global $blog_id;
+        wp_cache_switch_to_blog( $blog_id );
+
 }
 
 /**
@@ -155 +210 @@
  * @return bool False if not exists, true if contents were replaced
  */
 function wp_cache_replace( $key, $data, $group = '', $expire = 0 ) {
+        $result = apply_filters('wp_cache_replace', null, $key, $data, $group, (int) $expire);
+        if ( null !== $result ) {
+                return $result;
+        }
+
         global $wp_object_cache;
 
         return $wp_object_cache->replace( $key, $data, $group, (int) $expire );
@@ -175 +235 @@
  * @return bool False on failure, true on success
  */
 function wp_cache_set( $key, $data, $group = '', $expire = 0 ) {
+        $result = apply_filters('wp_cache_set', null, $key, $data, $group, (int) $expire);
+        if ( null !== $result ) {
+                return $result;
+        }
+
         global $wp_object_cache;
 
         return $wp_object_cache->set( $key, $data, $group, (int) $expire );
@@ -188 +253 @@
  * @since 3.5.0
  *
  * @param int $blog_id Blog ID
+ *
+ * @return mixed|void
  */
 function wp_cache_switch_to_blog( $blog_id ) {
+        $result = apply_filters( 'wp_cache_switch_to_blog', null, $blog_id );
+        if ( null !== $result ) {
+                return $result;
+        }
+
         global $wp_object_cache;
 
         return $wp_object_cache->switch_to_blog( $blog_id );
@@ -201 +273 @@
  * @since 2.6.0
  *
  * @param string|array $groups A group or an array of groups to add
+ *
+ * @return mixed|void
  */
 function wp_cache_add_global_groups( $groups ) {
+        $result = apply_filters('wp_cache_add_global_groups', null, $groups);
+        if ( null !== $result ) {
+                return $result;
+        }
         global $wp_object_cache;
 
         return $wp_object_cache->add_global_groups( $groups );
@@ -214 +292 @@
  * @since 2.6.0
  *
  * @param string|array $groups A group or an array of groups to add
+ *
+ * @return mixed|void
  */
 function wp_cache_add_non_persistent_groups( $groups ) {
+        $result = apply_filters( 'wp_cache_add_non_persistent_groups', null, $groups );
+        if ( null !== $result ) {
+                return $result;
+        }
         // Default cache doesn't persist so nothing to do here.
         return;
 }