Added clearing of cache groups

src/wp-includes/cache.php

@@ -102,6 +102,110 @@ function wp_cache_flush() {
 
 	return $wp_object_cache->flush();
 }
+/**
+ * Removes all cache items in a group.
+ *
+ * @since 6.0.0
+ *
+ * @see WP_Object_Cache::flush_group()
+ * @global WP_Object_Cache $wp_object_cache Object cache global instance.
+ *
+ * @param string|array $group name(s) of group to remove from cache.
+ *
+ * @return bool True on success, false on failure group not found.
+ */
+function wp_cache_flush_group( $group, $clear_linked = true ) {
+
+	global $wp_object_cache;
+
+	if ( ! wp_cache_supports_flushing_groups() ) {
+
+		return false;
+	}
+
+	// if group is an array loop and call each key in the array
+	if ( is_array( $group ) ) {
+
+		array_map( 'wp_cache_flush_group', array_values( $group ) );
+
+		return true;
+	}
+
+	// these are linked cache groups, so we have to flush them both if one is called
+	$cache_pairs = wp_cache_get_linked_meta();
+	if ( $clear_linked && isset( $cache_pairs[ $group ] ) ) {
+		foreach ( $cache_pairs[ $group ] as $cache_pair ) {
+			wp_cache_flush_group( $cache_pair, false );
+		}
+	}
+
+	/**
+	 * Filters to allow caching plugins to set this function to be called to flush groups.
+	 * See: filter "wp_cache_supports_flushing_groups" to declare group flushing is supported.
+	 *
+	 * @since 6.0.0
+	 *
+	 * @param string return $flush_group_function name of function to call from the cashing class.
+	 */
+	$flush_group_function = apply_filters( 'wp_cache_flush_group_function', 'flush_group' );
+	return $wp_object_cache->$flush_group_function( $group );
+}
+
+/**
+ * checks for group flushing capabilities
+ *
+ * @since 6.0.0
+ *
+ * @return bool True if group flushing is supported.
+ */
+function wp_cache_supports_flushing_groups() {
+	global $wp_object_cache;
+	/**
+	 * Filters to allow caching plugins to set this function to be called to flush groups.
+	 * See: filter "wp_cache_supports_flushing_groups" to declare group flushing is supported.
+	 *
+	 * @since 6.0.0
+	 *
+	 * @param string return $flush_group_function name of function to call from the cashing class.
+	 */
+	$flush_group_function = apply_filters( 'wp_cache_flush_group_function', 'flush_group' );
+	if ( method_exists( $wp_object_cache, $flush_group_function ) ) {
+		return true;
+	}
+
+	/**
+	 * Filters to allow caching plugins to declare if they support flushing groups.
+	 * See: filter "wp_cache_flush_group_function" to change the function used.
+	 *
+	 * @since 6.0.0
+	 *
+	 * @param boolean return true if your caching tool support group flushing.
+	 */
+	return apply_filters( 'wp_cache_supports_flushing_groups', false );
+}
+
+/**
+ * stores the mapping of linked cache groups
+ *
+ * @since 6.0.0
+ *
+ * @return array keyed by group, value is array of linked groups
+ */
+function wp_cache_get_linked_meta() {
+
+	/**
+	 * some the cache groups are linked, so we need to flush them both if one is called
+	 * this is the mapping for these groups
+	 *
+	 * @since 6.0.0
+	 *
+	 * @param array array of linked cache groups that need to delete as a set.
+	 */
+	return apply_filters( 'wp_cache_get_linked_meta',array(
+		'users'     => array( 'user_meta' ),
+		'user_meta' => array( 'users' ),
+	) );
+}
 
 /**
  * Retrieves the cache contents from the cache by key and group.

src/wp-includes/class-wp-object-cache.php

@@ -259,6 +259,19 @@ public function flush() {
 		return true;
 	}
 
+	/**
+	 * Clears the object cache of all data for the given group.
+	 *
+	 * @since 6.0.0
+	 *
+	 * @return true Always returns true.
+	 */
+	public function flush_group( $group ) {
+
+		unset( $this->cache[ $group ] );
+
+		return true;
+	}
 	/**
 	 * Retrieves the cache contents, if it exists.
 	 *

tests/phpunit/tests/cache.php

@@ -349,4 +349,211 @@ public function test_get_multiple() {
 
 		$this->assertSame( $expected, $found );
 	}
+
+	/**
+	 * @ticket 4476
+	 * @ticket 9773
+	 *
+	 * test wp_cache_flush_group
+	 *
+	 * @covers ::wp_cache_flush_group
+	 */
+	public function test_wp_cache_flush_group() {
+		$key = 'my-key';
+		$val = 'my-val';
+
+		wp_cache_set( $key, $val, 'group-test' );
+		wp_cache_set( $key, $val, 'group-kept' );
+		$this->assertSame( $val, wp_cache_get( $key, 'group-test' ), 'test_wp_cache_flush_group: group-test should contain my-val' );
+
+		wp_cache_flush_group( 'group-test' );
+		$this->assertFalse( wp_cache_get( $key, 'group-test' ), 'test_wp_cache_flush_group: group-test should return false' );
+		$this->assertSame( $val, wp_cache_get( $key, 'group-kept' ), 'test_wp_cache_flush_group: group-kept should still contain my-val' );
+	}
+
+	/**
+	 * @ticket 4476
+	 * @ticket 9773
+	 *
+	 * test wp_cache_flush_group with an array of groups
+	 *
+	 * @covers ::wp_cache_flush_groups
+	 */
+	public function test_wp_cache_flush_groups() {
+		$key = 'my-key';
+		$val = 'my-val';
+
+		wp_cache_set( $key, $val, 'group-test' );
+		wp_cache_set( $key, $val, 'group-test2' );
+		wp_cache_set( $key, $val, 'group-kept' );
+		$this->assertSame( $val, wp_cache_get( $key, 'group-test' ), 'test_wp_cache_flush_groups: group-test should contain my-val' );
+		$this->assertSame( $val, wp_cache_get( $key, 'group-test2' ), 'test_wp_cache_flush_groups: group-test2 should contain my-val' );
+
+		wp_cache_flush_group( array( 'group-test', 'group-test2' ) );
+		$this->assertFalse( wp_cache_get( $key, 'group-test' ), 'test_wp_cache_flush_groups: group-test should return false' );
+		$this->assertFalse( wp_cache_get( $key, 'group-test2' ), 'test_wp_cache_flush_groups: group-test2 should return false' );
+		$this->assertSame( $val, wp_cache_get( $key, 'group-kept' ), 'test_wp_cache_flush_groups: group-kept should still contain my-val' );
+	}
+
+	/**
+	 * @ticket 4476
+	 * @ticket 9773
+	 *
+	 * tests that is users cache is cleared user_meta is also cleared and vice versa.
+	 *
+	 * @covers ::wp_cache_flush_group
+	 */
+	public function test_wp_cache_flush_group_users() {
+		$key_users = 'my-user-key';
+		$val_users = 'my-user-val';
+		wp_cache_set( $key_users, $val_users, 'users' );
+
+		$key_meta = 'my-user_meta-key';
+		$val_meta = 'my-user_meta-val';
+		wp_cache_set( $key_meta, $val_meta, 'user_meta' );
+
+		wp_cache_flush_group( 'users' );
+		$this->assertFalse( wp_cache_get( $key_users, 'users' ), 'test_wp_cache_flush_group_users users: users should return false' );
+		$this->assertFalse( wp_cache_get( $key_meta, 'user_meta' ), 'test_wp_cache_flush_group_users users: user_meta should return false' );
+
+		wp_cache_set( $key_users, $val_users, 'users' );
+		wp_cache_set( $key_meta, $val_meta, 'user_meta' );
+
+		wp_cache_flush_group( 'user_meta' );
+		$this->assertFalse( wp_cache_get( $key_users, 'users' ), 'test_wp_cache_flush_group_users user_meta: users should return false' );
+		$this->assertFalse( wp_cache_get( $key_meta, 'user_meta' ), 'test_wp_cache_flush_group_users user_meta: user_meta should return false' );
+	}
+
+	/**
+	 * @ticket 4476
+	 * @ticket 9773
+	 *
+	 * test wp_cache_supports_flushing_groups
+	 *
+	 * @covers ::wp_cache_supports_flushing_groups
+	 */
+	public function test_wp_cache_supports_flushing_groups() {
+		$this->assertTrue( wp_cache_supports_flushing_groups(), 'test_wp_cache_supports_flushing_groups: should return true' );
+	}
+	/**
+	 * @ticket 4476
+	 * @ticket 9773
+	 *
+	 * test wp_cache_supports_flushing_groups
+	 *
+	 * @covers ::wp_cache_supports_flushing_groups
+	 */
+	public function test_wp_cache_supports_flushing_groups_no_support() {
+		global $wp_object_cache;
+		$temp            = $wp_object_cache;
+		$wp_object_cache = new stdClass();
+		$this->assertFalse( wp_cache_supports_flushing_groups(), 'test_wp_cache_supports_flushing_groups: should return false' );
+
+		$wp_object_cache = $temp;
+	}
+
+	/**
+	 * @ticket 4476
+	 * @ticket 9773
+	 *
+	 * test wp_cache_supports_flushing_groups
+	 *
+	 * @covers ::wp_cache_supports_flushing_groups
+	 */
+	public function test_wp_cache_supports_flushing_groups_filtered_function() {
+		global $wp_object_cache;
+		$temp            = $wp_object_cache;
+		$wp_object_cache = new WP_Object_Cache_dummy();
+
+		add_filter(
+			'wp_cache_flush_group_function',
+			static function() {
+				return 'dummy_function';
+			}
+		);
+
+		$this->assertTrue( wp_cache_supports_flushing_groups(), 'test_wp_cache_supports_flushing_groups: should return false' );
+
+		$wp_object_cache = $temp;
+	}
+	/**
+	 * @ticket 4476
+	 * @ticket 9773
+	 *
+	 * test wp_cache_supports_flushing_groups
+	 *
+	 * @covers ::wp_cache_supports_flushing_groups
+	 */
+	public function test_wp_cache_supports_flushing_groups_filtered() {
+		global $wp_object_cache;
+		$temp            = $wp_object_cache;
+		$wp_object_cache = new WP_Object_Cache_dummy();
+
+		add_filter( 'wp_cache_supports_flushing_groups', '__return_true' );
+
+		$this->assertTrue( wp_cache_supports_flushing_groups(), 'test_wp_cache_supports_flushing_groups with filter: should return true' );
+
+		$wp_object_cache = $temp;
+	}
+
+	/**
+	 * @ticket 4476
+	 * @ticket 9773
+	 *
+	 * test wp_cache_supports_flushing_groups
+	 *
+	 * @covers ::wp_cache_supports_flushing_groups
+	 */
+	public function test_wp_cache_flushing_groups_filtered() {
+		global $wp_object_cache;
+		$temp            = $wp_object_cache;
+		$wp_object_cache = new WP_Object_Cache_dummy();
+
+		add_filter(
+			'wp_cache_flush_group_function',
+			static function() {
+				return 'dummy_function';
+			}
+		);
+
+		$key = 'my-key';
+		$val = 'my-val';
+
+		wp_cache_set( $key, $val, 'group-test' );
+		wp_cache_set( $key, $val, 'group-kept' );
+		$this->assertTrue( wp_cache_flush_group( 'dummy_group' ) );
+
+		$wp_object_cache = $temp;
+	}
+
+
+
+	/**
+	 * @ticket 4476
+	 * @ticket 9773
+	 *
+	 * test wp_cache_get_linked_meta returns an array
+	 *
+	 * @covers ::wp_cache_get_linked_meta
+	 */
+	public function test_wp_cache_get_linked_meta() {
+
+		$this->assertIsArray( wp_cache_get_linked_meta() );
+	}
+
+
+}
+class WP_Object_Cache_dummy {
+	public function dummy_function() {
+		return true;
+	}
+	public function flush() {
+		return;
+	}
+	public function add_global_groups() {
+		return;
+	}
+	public function set() {
+		return;
+	}
 }