enmi-conf.org: comparison wp/wp-includes/meta.php

equal deleted inserted replaced

-:346c88efed21
+:5e2f62d02dcd
 /**
 * Add metadata for the specified object.
 *
 * @since 2.9.0
-* @uses $wpdb WordPress database object for queries.
+*
-* @uses do_action() Calls 'added_{$meta_type}_meta' with meta_id of added metadata entry,
+* @global wpdb $wpdb WordPress database abstraction object.
-* 		object ID, meta key, and meta value
 *
 * @param string $meta_type Type of object metadata is for (e.g., comment, post, or user)
 * @param int $object_id ID of the object metadata is for
 * @param string $meta_key Metadata key
 * @param mixed $meta_value Metadata value. Must be serializable if non-scalar.
 * @param bool $unique Optional, default is false. Whether the specified metadata key should be
 * 		unique for the object. If true, and the object already has a value for the specified
 * 		metadata key, no change will be made
-* @return int|bool The meta ID on successful update, false on failure.
+* @return int|bool The meta ID on success, false on failure.
 */
 function add_metadata($meta_type, $object_id, $meta_key, $meta_value, $unique = false) {
-	if ( !$meta_type || !$meta_key )
-		return false;
-	if ( !$object_id = absint($object_id) )
-		return false;
-	if ( ! $table = _get_meta_table($meta_type) )
-		return false;
 	global $wpdb;
+	if ( ! $meta_type || ! $meta_key || ! is_numeric( $object_id ) ) {
+		return false;
+	}
+	$object_id = absint( $object_id );
+	if ( ! $object_id ) {
+		return false;
+	}
+	$table = _get_meta_table( $meta_type );
+	if ( ! $table ) {
+		return false;
+	}
 	$column = sanitize_key($meta_type . '_id');
 	// expected_slashed ($meta_key)
 	$meta_key = wp_unslash($meta_key);
 	$meta_value = wp_unslash($meta_value);
 	$meta_value = sanitize_meta( $meta_key, $meta_value, $meta_type );
+	/**
+	 * Filter whether to add metadata of a specific type.
+	 *
+	 * The dynamic portion of the hook, `$meta_type`, refers to the meta
+	 * object type (comment, post, or user). Returning a non-null value
+	 * will effectively short-circuit the function.
+	 *
+	 * @since 3.1.0
+	 *
+	 * @param null|bool $check      Whether to allow adding metadata for the given type.
+	 * @param int       $object_id  Object ID.
+	 * @param string    $meta_key   Meta key.
+	 * @param mixed     $meta_value Meta value. Must be serializable if non-scalar.
+	 * @param bool      $unique     Whether the specified meta key should be unique
+	 *                              for the object. Optional. Default false.
+	 */
 	$check = apply_filters( "add_{$meta_type}_metadata", null, $object_id, $meta_key, $meta_value, $unique );
 	if ( null !== $check )
 		return $check;
 	if ( $unique && $wpdb->get_var( $wpdb->prepare(
 		return false;
 	$_meta_value = $meta_value;
 	$meta_value = maybe_serialize( $meta_value );
+	/**
+	 * Fires immediately before meta of a specific type is added.
+	 *
+	 * The dynamic portion of the hook, `$meta_type`, refers to the meta
+	 * object type (comment, post, or user).
+	 *
+	 * @since 3.1.0
+	 *
+	 * @param int    $object_id  Object ID.
+	 * @param string $meta_key   Meta key.
+	 * @param mixed  $meta_value Meta value.
+	 */
 	do_action( "add_{$meta_type}_meta", $object_id, $meta_key, $_meta_value );
 	$result = $wpdb->insert( $table, array(
 		$column => $object_id,
 		'meta_key' => $meta_key,
 	$mid = (int) $wpdb->insert_id;
 	wp_cache_delete($object_id, $meta_type . '_meta');
+	/**
+	 * Fires immediately after meta of a specific type is added.
+	 *
+	 * The dynamic portion of the hook, `$meta_type`, refers to the meta
+	 * object type (comment, post, or user).
+	 *
+	 * @since 2.9.0
+	 *
+	 * @param int    $mid        The meta ID after successful update.
+	 * @param int    $object_id  Object ID.
+	 * @param string $meta_key   Meta key.
+	 * @param mixed  $meta_value Meta value.
+	 */
 	do_action( "added_{$meta_type}_meta", $mid, $object_id, $meta_key, $_meta_value );
 	return $mid;
 }
 /**
 * Update metadata for the specified object. If no value already exists for the specified object
 * ID and metadata key, the metadata will be added.
 *
 * @since 2.9.0
-* @uses $wpdb WordPress database object for queries.
+*
-* @uses do_action() Calls 'update_{$meta_type}_meta' before updating metadata with meta_id of
+* @global wpdb $wpdb WordPress database abstraction object.
-* 		metadata entry to update, object ID, meta key, and meta value
-* @uses do_action() Calls 'updated_{$meta_type}_meta' after updating metadata with meta_id of
-* 		updated metadata entry, object ID, meta key, and meta value
 *
 * @param string $meta_type Type of object metadata is for (e.g., comment, post, or user)
 * @param int $object_id ID of the object metadata is for
 * @param string $meta_key Metadata key
 * @param mixed $meta_value Metadata value. Must be serializable if non-scalar.
 * @param mixed $prev_value Optional. If specified, only update existing metadata entries with
 * 		the specified value. Otherwise, update all entries.
-* @return bool True on successful update, false on failure.
+* @return int|bool Meta ID if the key didn't exist, true on successful update, false on failure.
 */
 function update_metadata($meta_type, $object_id, $meta_key, $meta_value, $prev_value = '') {
-	if ( !$meta_type || !$meta_key )
-		return false;
-	if ( !$object_id = absint($object_id) )
-		return false;
-	if ( ! $table = _get_meta_table($meta_type) )
-		return false;
 	global $wpdb;
+	if ( ! $meta_type || ! $meta_key || ! is_numeric( $object_id ) ) {
+		return false;
+	}
+	$object_id = absint( $object_id );
+	if ( ! $object_id ) {
+		return false;
+	}
+	$table = _get_meta_table( $meta_type );
+	if ( ! $table ) {
+		return false;
+	}
 	$column = sanitize_key($meta_type . '_id');
 	$id_column = 'user' == $meta_type ? 'umeta_id' : 'meta_id';
 	// expected_slashed ($meta_key)
 	$meta_key = wp_unslash($meta_key);
 	$passed_value = $meta_value;
 	$meta_value = wp_unslash($meta_value);
 	$meta_value = sanitize_meta( $meta_key, $meta_value, $meta_type );
+	/**
+	 * Filter whether to update metadata of a specific type.
+	 *
+	 * The dynamic portion of the hook, `$meta_type`, refers to the meta
+	 * object type (comment, post, or user). Returning a non-null value
+	 * will effectively short-circuit the function.
+	 *
+	 * @since 3.1.0
+	 *
+	 * @param null|bool $check      Whether to allow updating metadata for the given type.
+	 * @param int       $object_id  Object ID.
+	 * @param string    $meta_key   Meta key.
+	 * @param mixed     $meta_value Meta value. Must be serializable if non-scalar.
+	 * @param mixed     $prev_value Optional. If specified, only update existing
+	 *                              metadata entries with the specified value.
+	 *                              Otherwise, update all entries.
+	 */
 	$check = apply_filters( "update_{$meta_type}_metadata", null, $object_id, $meta_key, $meta_value, $prev_value );
 	if ( null !== $check )
 		return (bool) $check;
 	// Compare existing value to new value if no prev value given and the key exists only once.
 			if ( $old_value[0] === $meta_value )
 				return false;
 		}
 	}
-	if ( ! $meta_id = $wpdb->get_var( $wpdb->prepare( "SELECT $id_column FROM $table WHERE meta_key = %s AND $column = %d", $meta_key, $object_id ) ) )
+	$meta_ids = $wpdb->get_col( $wpdb->prepare( "SELECT $id_column FROM $table WHERE meta_key = %s AND $column = %d", $meta_key, $object_id ) );
+	if ( empty( $meta_ids ) ) {
 		return add_metadata($meta_type, $object_id, $meta_key, $passed_value);
+	}
 	$_meta_value = $meta_value;
 	$meta_value = maybe_serialize( $meta_value );
 	$data  = compact( 'meta_value' );
 	if ( !empty( $prev_value ) ) {
 		$prev_value = maybe_serialize($prev_value);
 		$where['meta_value'] = $prev_value;
 	}
-	do_action( "update_{$meta_type}_meta", $meta_id, $object_id, $meta_key, $_meta_value );
+	foreach ( $meta_ids as $meta_id ) {
+		/**
-	if ( 'post' == $meta_type )
+		 * Fires immediately before updating metadata of a specific type.
-		do_action( 'update_postmeta', $meta_id, $object_id, $meta_key, $meta_value );
+		 *
+		 * The dynamic portion of the hook, `$meta_type`, refers to the meta
+		 * object type (comment, post, or user).
+		 *
+		 * @since 2.9.0
+		 *
+		 * @param int    $meta_id    ID of the metadata entry to update.
+		 * @param int    $object_id  Object ID.
+		 * @param string $meta_key   Meta key.
+		 * @param mixed  $meta_value Meta value.
+		 */
+		do_action( "update_{$meta_type}_meta", $meta_id, $object_id, $meta_key, $_meta_value );
+	}
+	if ( 'post' == $meta_type ) {
+		foreach ( $meta_ids as $meta_id ) {
+			/**
+			 * Fires immediately before updating a post's metadata.
+			 *
+			 * @since 2.9.0
+			 *
+			 * @param int    $meta_id    ID of metadata entry to update.
+			 * @param int    $object_id  Object ID.
+			 * @param string $meta_key   Meta key.
+			 * @param mixed  $meta_value Meta value.
+			 */
+			do_action( 'update_postmeta', $meta_id, $object_id, $meta_key, $meta_value );
+		}
+	}
 	$result = $wpdb->update( $table, $data, $where );
 	if ( ! $result )
 		return false;
 	wp_cache_delete($object_id, $meta_type . '_meta');
-	do_action( "updated_{$meta_type}_meta", $meta_id, $object_id, $meta_key, $_meta_value );
+	foreach ( $meta_ids as $meta_id ) {
+		/**
-	if ( 'post' == $meta_type )
+		 * Fires immediately after updating metadata of a specific type.
-		do_action( 'updated_postmeta', $meta_id, $object_id, $meta_key, $meta_value );
+		 *
+		 * The dynamic portion of the hook, `$meta_type`, refers to the meta
+		 * object type (comment, post, or user).
+		 *
+		 * @since 2.9.0
+		 *
+		 * @param int    $meta_id    ID of updated metadata entry.
+		 * @param int    $object_id  Object ID.
+		 * @param string $meta_key   Meta key.
+		 * @param mixed  $meta_value Meta value.
+		 */
+		do_action( "updated_{$meta_type}_meta", $meta_id, $object_id, $meta_key, $_meta_value );
+	}
+	if ( 'post' == $meta_type ) {
+		foreach ( $meta_ids as $meta_id ) {
+			/**
+			 * Fires immediately after updating a post's metadata.
+			 *
+			 * @since 2.9.0
+			 *
+			 * @param int    $meta_id    ID of updated metadata entry.
+			 * @param int    $object_id  Object ID.
+			 * @param string $meta_key   Meta key.
+			 * @param mixed  $meta_value Meta value.
+			 */
+			do_action( 'updated_postmeta', $meta_id, $object_id, $meta_key, $meta_value );
+		}
+	}
 	return true;
 }
 /**
 * Delete metadata for the specified object.
 *
 * @since 2.9.0
-* @uses $wpdb WordPress database object for queries.
+*
-* @uses do_action() Calls 'deleted_{$meta_type}_meta' after deleting with meta_id of
+* @global wpdb $wpdb WordPress database abstraction object.
-* 		deleted metadata entries, object ID, meta key, and meta value
 *
 * @param string $meta_type Type of object metadata is for (e.g., comment, post, or user)
 * @param int $object_id ID of the object metadata is for
 * @param string $meta_key Metadata key
 * @param mixed $meta_value Optional. Metadata value. Must be serializable if non-scalar. If specified, only delete metadata entries
 * 		for all objects, ignoring the specified object_id. Otherwise, only delete matching
 * 		metadata entries for the specified object_id.
 * @return bool True on successful delete, false on failure.
 */
 function delete_metadata($meta_type, $object_id, $meta_key, $meta_value = '', $delete_all = false) {
-	if ( !$meta_type || !$meta_key )
-		return false;
-	if ( (!$object_id = absint($object_id)) && !$delete_all )
-		return false;
-	if ( ! $table = _get_meta_table($meta_type) )
-		return false;
 	global $wpdb;
+	if ( ! $meta_type || ! $meta_key || ! is_numeric( $object_id ) && ! $delete_all ) {
+		return false;
+	}
+	$object_id = absint( $object_id );
+	if ( ! $object_id && ! $delete_all ) {
+		return false;
+	}
+	$table = _get_meta_table( $meta_type );
+	if ( ! $table ) {
+		return false;
+	}
 	$type_column = sanitize_key($meta_type . '_id');
 	$id_column = 'user' == $meta_type ? 'umeta_id' : 'meta_id';
 	// expected_slashed ($meta_key)
 	$meta_key = wp_unslash($meta_key);
 	$meta_value = wp_unslash($meta_value);
+	/**
+	 * Filter whether to delete metadata of a specific type.
+	 *
+	 * The dynamic portion of the hook, `$meta_type`, refers to the meta
+	 * object type (comment, post, or user). Returning a non-null value
+	 * will effectively short-circuit the function.
+	 *
+	 * @since 3.1.0
+	 *
+	 * @param null|bool $delete     Whether to allow metadata deletion of the given type.
+	 * @param int       $object_id  Object ID.
+	 * @param string    $meta_key   Meta key.
+	 * @param mixed     $meta_value Meta value. Must be serializable if non-scalar.
+	 * @param bool      $delete_all Whether to delete the matching metadata entries
+	 *                              for all objects, ignoring the specified $object_id.
+	 *                              Default false.
+	 */
 	$check = apply_filters( "delete_{$meta_type}_metadata", null, $object_id, $meta_key, $meta_value, $delete_all );
 	if ( null !== $check )
 		return (bool) $check;
 	$_meta_value = $meta_value;
 		return false;
 	if ( $delete_all )
 		$object_ids = $wpdb->get_col( $wpdb->prepare( "SELECT $type_column FROM $table WHERE meta_key = %s", $meta_key ) );
+	/**
+	 * Fires immediately before deleting metadata of a specific type.
+	 *
+	 * The dynamic portion of the hook, `$meta_type`, refers to the meta
+	 * object type (comment, post, or user).
+	 *
+	 * @since 3.1.0
+	 *
+	 * @param array  $meta_ids   An array of metadata entry IDs to delete.
+	 * @param int    $object_id  Object ID.
+	 * @param string $meta_key   Meta key.
+	 * @param mixed  $meta_value Meta value.
+	 */
 	do_action( "delete_{$meta_type}_meta", $meta_ids, $object_id, $meta_key, $_meta_value );
 	// Old-style action.
-	if ( 'post' == $meta_type )
+	if ( 'post' == $meta_type ) {
+		/**
+		 * Fires immediately before deleting metadata for a post.
+		 *
+		 * @since 2.9.0
+		 *
+		 * @param array $meta_ids An array of post metadata entry IDs to delete.
+		 */
 		do_action( 'delete_postmeta', $meta_ids );
+	}
 	$query = "DELETE FROM $table WHERE $id_column IN( " . implode( ',', $meta_ids ) . " )";
 	$count = $wpdb->query($query);
 		}
 	} else {
 		wp_cache_delete($object_id, $meta_type . '_meta');
 	}
+	/**
+	 * Fires immediately after deleting metadata of a specific type.
+	 *
+	 * The dynamic portion of the hook name, `$meta_type`, refers to the meta
+	 * object type (comment, post, or user).
+	 *
+	 * @since 2.9.0
+	 *
+	 * @param array  $meta_ids   An array of deleted metadata entry IDs.
+	 * @param int    $object_id  Object ID.
+	 * @param string $meta_key   Meta key.
+	 * @param mixed  $meta_value Meta value.
+	 */
 	do_action( "deleted_{$meta_type}_meta", $meta_ids, $object_id, $meta_key, $_meta_value );
 	// Old-style action.
-	if ( 'post' == $meta_type )
+	if ( 'post' == $meta_type ) {
+		/**
+		 * Fires immediately after deleting metadata for a post.
+		 *
+		 * @since 2.9.0
+		 *
+		 * @param array $meta_ids An array of deleted post metadata entry IDs.
+		 */
 		do_action( 'deleted_postmeta', $meta_ids );
+	}
 	return true;
 }
 /**
 * @param int $object_id ID of the object metadata is for
 * @param string $meta_key Optional. Metadata key. If not specified, retrieve all metadata for
 * 		the specified object.
 * @param bool $single Optional, default is false. If true, return only the first value of the
 * 		specified meta_key. This parameter has no effect if meta_key is not specified.
-* @return string|array Single metadata value, or array of values
+* @return mixed Single metadata value, or array of values
 */
 function get_metadata($meta_type, $object_id, $meta_key = '', $single = false) {
-	if ( !$meta_type )
+	if ( ! $meta_type || ! is_numeric( $object_id ) ) {
 		return false;
+	}
-	if ( !$object_id = absint($object_id) )
-		return false;
+	$object_id = absint( $object_id );
+	if ( ! $object_id ) {
+		return false;
+	}
+	/**
+	 * Filter whether to retrieve metadata of a specific type.
+	 *
+	 * The dynamic portion of the hook, `$meta_type`, refers to the meta
+	 * object type (comment, post, or user). Returning a non-null value
+	 * will effectively short-circuit the function.
+	 *
+	 * @since 3.1.0
+	 *
+	 * @param null|array|string $value     The value get_metadata() should
+	 *                                     return - a single metadata value,
+	 *                                     or an array of values.
+	 * @param int               $object_id Object ID.
+	 * @param string            $meta_key  Meta key.
+	 * @param string|array      $single    Meta value, or an array of values.
+	 */
 	$check = apply_filters( "get_{$meta_type}_metadata", null, $object_id, $meta_key, $single );
 	if ( null !== $check ) {
 		if ( $single && is_array( $check ) )
 			return $check[0];
 		else
 	if ( !$meta_cache ) {
 		$meta_cache = update_meta_cache( $meta_type, array( $object_id ) );
 		$meta_cache = $meta_cache[$object_id];
 	}
-	if ( !$meta_key )
+	if ( ! $meta_key ) {
 		return $meta_cache;
+	}
 	if ( isset($meta_cache[$meta_key]) ) {
 		if ( $single )
 			return maybe_unserialize( $meta_cache[$meta_key][0] );
 		else
 * @param int $object_id ID of the object metadata is for
 * @param string $meta_key Metadata key.
 * @return boolean true of the key is set, false if not.
 */
 function metadata_exists( $meta_type, $object_id, $meta_key ) {
-	if ( ! $meta_type )
+	if ( ! $meta_type || ! is_numeric( $object_id ) ) {
 		return false;
+	}
-	if ( ! $object_id = absint( $object_id ) )
-		return false;
+	$object_id = absint( $object_id );
+	if ( ! $object_id ) {
+		return false;
+	}
+	/** This filter is documented in wp-includes/meta.php */
 	$check = apply_filters( "get_{$meta_type}_metadata", null, $object_id, $meta_key, true );
 	if ( null !== $check )
-		return true;
+		return (bool) $check;
 	$meta_cache = wp_cache_get( $object_id, $meta_type . '_meta' );
 	if ( !$meta_cache ) {
 		$meta_cache = update_meta_cache( $meta_type, array( $object_id ) );
 * @return object Meta object or false.
 */
 function get_metadata_by_mid( $meta_type, $meta_id ) {
 	global $wpdb;
-	if ( ! $meta_type )
+	if ( ! $meta_type || ! is_numeric( $meta_id ) ) {
 		return false;
+	}
-	if ( !$meta_id = absint( $meta_id ) )
-		return false;
+	$meta_id = absint( $meta_id );
+	if ( ! $meta_id ) {
-	if ( ! $table = _get_meta_table($meta_type) )
+		return false;
-		return false;
+	}
+	$table = _get_meta_table( $meta_type );
+	if ( ! $table ) {
+		return false;
+	}
 	$id_column = ( 'user' == $meta_type ) ? 'umeta_id' : 'meta_id';
 	$meta = $wpdb->get_row( $wpdb->prepare( "SELECT * FROM $table WHERE $id_column = %d", $meta_id ) );
 /**
 * Update meta data by meta ID
 *
 * @since 3.3.0
-*
-* @uses get_metadata_by_mid() Calls get_metadata_by_mid() to fetch the meta key, value
-*		and object_id of the given meta_id.
 *
 * @param string $meta_type Type of object metadata is for (e.g., comment, post, or user)
 * @param int $meta_id ID for a specific meta row
 * @param string $meta_value Metadata value
 * @param string $meta_key Optional, you can provide a meta key to update it
 */
 function update_metadata_by_mid( $meta_type, $meta_id, $meta_value, $meta_key = false ) {
 	global $wpdb;
 	// Make sure everything is valid.
-	if ( ! $meta_type )
+	if ( ! $meta_type || ! is_numeric( $meta_id ) ) {
 		return false;
+	}
-	if ( ! $meta_id = absint( $meta_id ) )
-		return false;
+	$meta_id = absint( $meta_id );
+	if ( ! $meta_id ) {
-	if ( ! $table = _get_meta_table( $meta_type ) )
+		return false;
-		return false;
+	}
+	$table = _get_meta_table( $meta_type );
+	if ( ! $table ) {
+		return false;
+	}
 	$column = sanitize_key($meta_type . '_id');
 	$id_column = 'user' == $meta_type ? 'umeta_id' : 'meta_id';
 	// Fetch the meta and go on if it's found.
 	if ( $meta = get_metadata_by_mid( $meta_type, $meta_id ) ) {
 		$original_key = $meta->meta_key;
-		$original_value = $meta->meta_value;
 		$object_id = $meta->{$column};
 		// If a new meta_key (last parameter) was specified, change the meta key,
 		// otherwise use the original key in the update statement.
 		if ( false === $meta_key ) {
 		// Format the where query arguments.
 		$where = array();
 		$where[$id_column] = $meta_id;
+		/** This action is documented in wp-includes/meta.php */
 		do_action( "update_{$meta_type}_meta", $meta_id, $object_id, $meta_key, $_meta_value );
-		if ( 'post' == $meta_type )
+		if ( 'post' == $meta_type ) {
+			/** This action is documented in wp-includes/meta.php */
 			do_action( 'update_postmeta', $meta_id, $object_id, $meta_key, $meta_value );
+		}
 		// Run the update query, all fields in $data are %s, $where is a %d.
 		$result = $wpdb->update( $table, $data, $where, '%s', '%d' );
 		if ( ! $result )
 			return false;
 		// Clear the caches.
 		wp_cache_delete($object_id, $meta_type . '_meta');
+		/** This action is documented in wp-includes/meta.php */
 		do_action( "updated_{$meta_type}_meta", $meta_id, $object_id, $meta_key, $_meta_value );
-		if ( 'post' == $meta_type )
+		if ( 'post' == $meta_type ) {
+			/** This action is documented in wp-includes/meta.php */
 			do_action( 'updated_postmeta', $meta_id, $object_id, $meta_key, $meta_value );
+		}
 		return true;
 	}
 	// And if the meta was not found.
 /**
 * Delete meta data by meta ID
 *
 * @since 3.3.0
-*
-* @uses get_metadata_by_mid() Calls get_metadata_by_mid() to fetch the meta key, value
-*		and object_id of the given meta_id.
 *
 * @param string $meta_type Type of object metadata is for (e.g., comment, post, or user)
 * @param int $meta_id ID for a specific meta row
 * @return bool True on successful delete, false on failure.
 */
 function delete_metadata_by_mid( $meta_type, $meta_id ) {
 	global $wpdb;
 	// Make sure everything is valid.
-	if ( ! $meta_type )
+	if ( ! $meta_type || ! is_numeric( $meta_id ) ) {
 		return false;
+	}
-	if ( ! $meta_id = absint( $meta_id ) )
-		return false;
+	$meta_id = absint( $meta_id );
+	if ( ! $meta_id ) {
-	if ( ! $table = _get_meta_table( $meta_type ) )
+		return false;
-		return false;
+	}
+	$table = _get_meta_table( $meta_type );
+	if ( ! $table ) {
+		return false;
+	}
 	// object and id columns
 	$column = sanitize_key($meta_type . '_id');
 	$id_column = 'user' == $meta_type ? 'umeta_id' : 'meta_id';
 	// Fetch the meta and go on if it's found.
 	if ( $meta = get_metadata_by_mid( $meta_type, $meta_id ) ) {
 		$object_id = $meta->{$column};
+		/** This action is documented in wp-includes/meta.php */
 		do_action( "delete_{$meta_type}_meta", (array) $meta_id, $object_id, $meta->meta_key, $meta->meta_value );
 		// Old-style action.
-		if ( 'post' == $meta_type || 'comment' == $meta_type )
+		if ( 'post' == $meta_type || 'comment' == $meta_type ) {
+			/**
+			 * Fires immediately before deleting post or comment metadata of a specific type.
+			 *
+			 * The dynamic portion of the hook, `$meta_type`, refers to the meta
+			 * object type (post or comment).
+			 *
+			 * @since 3.4.0
+			 *
+			 * @param int $meta_id ID of the metadata entry to delete.
+			 */
 			do_action( "delete_{$meta_type}meta", $meta_id );
+		}
 		// Run the query, will return true if deleted, false otherwise
 		$result = (bool) $wpdb->delete( $table, array( $id_column => $meta_id ) );
 		// Clear the caches.
 		wp_cache_delete($object_id, $meta_type . '_meta');
+		/** This action is documented in wp-includes/meta.php */
 		do_action( "deleted_{$meta_type}_meta", (array) $meta_id, $object_id, $meta->meta_key, $meta->meta_value );
 		// Old-style action.
-		if ( 'post' == $meta_type || 'comment' == $meta_type )
+		if ( 'post' == $meta_type || 'comment' == $meta_type ) {
+			/**
+			 * Fires immediately after deleting post or comment metadata of a specific type.
+			 *
+			 * The dynamic portion of the hook, `$meta_type`, refers to the meta
+			 * object type (post or comment).
+			 *
+			 * @since 3.4.0
+			 *
+			 * @param int $meta_ids Deleted metadata entry ID.
+			 */
 			do_action( "deleted_{$meta_type}meta", $meta_id );
+		}
 		return $result;
 	}
 /**
 * Update the metadata cache for the specified objects.
 *
 * @since 2.9.0
-* @uses $wpdb WordPress database object for queries.
+*
+* @global wpdb $wpdb WordPress database abstraction object.
 *
 * @param string $meta_type Type of object metadata is for (e.g., comment, post, or user)
 * @param int|array $object_ids array or comma delimited list of object IDs to update cache for
 * @return mixed Metadata cache for the specified objects, or false on failure.
 */
 function update_meta_cache($meta_type, $object_ids) {
-	if ( empty( $meta_type ) || empty( $object_ids ) )
+	global $wpdb;
-		return false;
+	if ( ! $meta_type || ! $object_ids ) {
-	if ( ! $table = _get_meta_table($meta_type) )
+		return false;
-		return false;
+	}
+	$table = _get_meta_table( $meta_type );
+	if ( ! $table ) {
+		return false;
+	}
 	$column = sanitize_key($meta_type . '_id');
-	global $wpdb;
 	if ( !is_array($object_ids) ) {
 		$object_ids = preg_replace('|[^0-9,]|', '', $object_ids);
 		$object_ids = explode(',', $object_ids);
 	}
 	if ( empty( $ids ) )
 		return $cache;
 	// Get meta info
-	$id_list = join(',', $ids);
+	$id_list = join( ',', $ids );
-	$meta_list = $wpdb->get_results( $wpdb->prepare("SELECT $column, meta_key, meta_value FROM $table WHERE $column IN ($id_list)",
+	$id_column = 'user' == $meta_type ? 'umeta_id' : 'meta_id';
-		$meta_type), ARRAY_A );
+	$meta_list = $wpdb->get_results( "SELECT $column, meta_key, meta_value FROM $table WHERE $column IN ($id_list) ORDER BY $id_column ASC", ARRAY_A );
 	if ( !empty($meta_list) ) {
 		foreach ( $meta_list as $metarow) {
 			$mpid = intval($metarow[$column]);
 			$mkey = $metarow['meta_key'];
 	return $cache;
 }
 /**
-* Given a meta query, generates SQL clauses to be appended to a main query
+* Given a meta query, generates SQL clauses to be appended to a main query.
 *
 * @since 3.2.0
 *
 * @see WP_Meta_Query
 *
-* @param array $meta_query A meta query
+* @param array $meta_query         A meta query.
-* @param string $type Type of meta
+* @param string $type              Type of meta.
-* @param string $primary_table
+* @param string $primary_table     Primary database table name.
-* @param string $primary_id_column
+* @param string $primary_id_column Primary ID column name.
-* @param object $context (optional) The main query object
+* @param object $context           Optional. The main query object
-* @return array( 'join' => $join_sql, 'where' => $where_sql )
+* @return array Associative array of `JOIN` and `WHERE` SQL.
 */
 function get_meta_sql( $meta_query, $type, $primary_table, $primary_id_column, $context = null ) {
 	$meta_query_obj = new WP_Meta_Query( $meta_query );
 	return $meta_query_obj->get_sql( $type, $primary_table, $primary_id_column, $context );
 }
 /**
-* Container class for a multiple metadata query
+* Class for generating SQL clauses that filter a primary query according to metadata keys and values.
+*
+* `WP_Meta_Query` is a helper that allows primary query classes, such as {@see WP_Query} and {@see WP_User_Query},
+* to filter their results by object metadata, by generating `JOIN` and `WHERE` subclauses to be attached
+* to the primary SQL query string.
 *
 * @since 3.2.0
 */
 class WP_Meta_Query {
 	/**
-	* List of metadata queries. A single query is an associative array:
+	 * Array of metadata queries.
-	* - 'key' string The meta key
+	 *
-	* - 'value' string|array The meta value
+	 * See {@see WP_Meta_Query::__construct()} for information on meta query arguments.
-	* - 'compare' (optional) string How to compare the key to the value.
+	 *
-	*              Possible values: '=', '!=', '>', '>=', '<', '<=', 'LIKE', 'NOT LIKE', 'IN', 'NOT IN',
+	 * @since 3.2.0
-	*              'BETWEEN', 'NOT BETWEEN', 'REGEXP', 'NOT REGEXP', 'RLIKE'.
+	 * @access public
-	*              Default: '='
+	 * @var array
-	* - 'type' string (optional) The type of the value.
+	 */
-	*              Possible values: 'NUMERIC', 'BINARY', 'CHAR', 'DATE', 'DATETIME', 'DECIMAL', 'SIGNED', 'TIME', 'UNSIGNED'.
-	*              Default: 'CHAR'
-	*
-	* @since 3.2.0
-	* @access public
-	* @var array
-	*/
 	public $queries = array();
 	/**
 	 * The relation between the queries. Can be one of 'AND' or 'OR'.
 	 *
 	 * @var string
 	 */
 	public $relation;
 	/**
-	 * Constructor
+	 * Database table to query for the metadata.
 	 *
-	 * @param array $meta_query (optional) A meta query
+	 * @since 4.1.0
-	 */
+	 * @access public
-	function __construct( $meta_query = false ) {
+	 * @var string
+	 */
+	public $meta_table;
+	/**
+	 * Column in meta_table that represents the ID of the object the metadata belongs to.
+	 *
+	 * @since 4.1.0
+	 * @access public
+	 * @var string
+	 */
+	public $meta_id_column;
+	/**
+	 * Database table that where the metadata's objects are stored (eg $wpdb->users).
+	 *
+	 * @since 4.1.0
+	 * @access public
+	 * @var string
+	 */
+	public $primary_table;
+	/**
+	 * Column in primary_table that represents the ID of the object.
+	 *
+	 * @since 4.1.0
+	 * @access public
+	 * @var string
+	 */
+	public $primary_id_column;
+	/**
+	 * A flat list of table aliases used in JOIN clauses.
+	 *
+	 * @since 4.1.0
+	 * @access protected
+	 * @var array
+	 */
+	protected $table_aliases = array();
+	/**
+	 * A flat list of clauses, keyed by clause 'name'.
+	 *
+	 * @since 4.2.0
+	 * @access protected
+	 * @var array
+	 */
+	protected $clauses = array();
+	/**
+	 * Constructor.
+	 *
+	 * @since 3.2.0
+	 * @since 4.2.0 Introduced support for naming query clauses by associative array keys.
+	 *
+	 * @access public
+	 *
+	 * @param array $meta_query {
+	 *     Array of meta query clauses. When first-order clauses use strings as their array keys, they may be
+	 *     referenced in the 'orderby' parameter of the parent query.
+	 *
+	 *     @type string $relation Optional. The MySQL keyword used to join
+	 *                            the clauses of the query. Accepts 'AND', or 'OR'. Default 'AND'.
+	 *     @type array {
+	 *         Optional. An array of first-order clause parameters, or another fully-formed meta query.
+	 *
+	 *         @type string $key     Meta key to filter by.
+	 *         @type string $value   Meta value to filter by.
+	 *         @type string $compare MySQL operator used for comparing the $value. Accepts '=',
+	 *                               '!=', '>', '>=', '<', '<=', 'LIKE', 'NOT LIKE', 'IN', 'NOT IN',
+	 *                               'BETWEEN', 'NOT BETWEEN', 'REGEXP', 'NOT REGEXP', or 'RLIKE'.
+	 *                               Default is 'IN' when `$value` is an array, '=' otherwise.
+	 *         @type string $type    MySQL data type that the meta_value column will be CAST to for
+	 *                               comparisons. Accepts 'NUMERIC', 'BINARY', 'CHAR', 'DATE',
+	 *                               'DATETIME', 'DECIMAL', 'SIGNED', 'TIME', or 'UNSIGNED'.
+	 *                               Default is 'CHAR'.
+	 *     }
+	 * }
+	 */
+	public function __construct( $meta_query = false ) {
 		if ( !$meta_query )
 			return;
 		if ( isset( $meta_query['relation'] ) && strtoupper( $meta_query['relation'] ) == 'OR' ) {
 			$this->relation = 'OR';
 		} else {
 			$this->relation = 'AND';
 		}
-		$this->queries = array();
+		$this->queries = $this->sanitize_query( $meta_query );
+	}
-		foreach ( $meta_query as $key => $query ) {
-			if ( ! is_array( $query ) )
+	/**
+	 * Ensure the 'meta_query' argument passed to the class constructor is well-formed.
+	 *
+	 * Eliminates empty items and ensures that a 'relation' is set.
+	 *
+	 * @since 4.1.0
+	 * @access public
+	 *
+	 * @param array $queries Array of query clauses.
+	 * @return array Sanitized array of query clauses.
+	 */
+	public function sanitize_query( $queries ) {
+		$clean_queries = array();
+		if ( ! is_array( $queries ) ) {
+			return $clean_queries;
+		}
+		foreach ( $queries as $key => $query ) {
+			if ( 'relation' === $key ) {
+				$relation = $query;
+			} elseif ( ! is_array( $query ) ) {
 				continue;
-			$this->queries[] = $query;
+			// First-order clause.
-		}
+			} elseif ( $this->is_first_order_clause( $query ) ) {
+				if ( isset( $query['value'] ) && array() === $query['value'] ) {
+					unset( $query['value'] );
+				}
+				$clean_queries[ $key ] = $query;
+			// Otherwise, it's a nested query, so we recurse.
+			} else {
+				$cleaned_query = $this->sanitize_query( $query );
+				if ( ! empty( $cleaned_query ) ) {
+					$clean_queries[ $key ] = $cleaned_query;
+				}
+			}
+		}
+		if ( empty( $clean_queries ) ) {
+			return $clean_queries;
+		}
+		// Sanitize the 'relation' key provided in the query.
+		if ( isset( $relation ) && 'OR' === strtoupper( $relation ) ) {
+			$clean_queries['relation'] = 'OR';
+		/*
+		 * If there is only a single clause, call the relation 'OR'.
+		 * This value will not actually be used to join clauses, but it
+		 * simplifies the logic around combining key-only queries.
+		 */
+		} elseif ( 1 === count( $clean_queries ) ) {
+			$clean_queries['relation'] = 'OR';
+		// Default to AND.
+		} else {
+			$clean_queries['relation'] = 'AND';
+		}
+		return $clean_queries;
+	}
+	/**
+	 * Determine whether a query clause is first-order.
+	 *
+	 * A first-order meta query clause is one that has either a 'key' or
+	 * a 'value' array key.
+	 *
+	 * @since 4.1.0
+	 * @access protected
+	 *
+	 * @param array $query Meta query arguments.
+	 * @return bool Whether the query clause is a first-order clause.
+	 */
+	protected function is_first_order_clause( $query ) {
+		return isset( $query['key'] ) || isset( $query['value'] );
 	}
 	/**
 	 * Constructs a meta query based on 'meta_*' query vars
 	 *
 	 * @since 3.2.0
 	 * @access public
 	 *
 	 * @param array $qv The query variables
 	 */
-	function parse_query_vars( $qv ) {
+	public function parse_query_vars( $qv ) {
 		$meta_query = array();
-		// Simple query needs to be first for orderby=meta_value to work correctly
+		/*
+		 * For orderby=meta_value to work correctly, simple query needs to be
+		 * first (so that its table join is against an unaliased meta table) and
+		 * needs to be its own clause (so it doesn't interfere with the logic of
+		 * the rest of the meta_query).
+		 */
+		$primary_meta_query = array();
 		foreach ( array( 'key', 'compare', 'type' ) as $key ) {
-			if ( !empty( $qv[ "meta_$key" ] ) )
+			if ( ! empty( $qv[ "meta_$key" ] ) ) {
-				$meta_query[0][ $key ] = $qv[ "meta_$key" ];
+				$primary_meta_query[ $key ] = $qv[ "meta_$key" ];
-		}
+			}
+		}
-		// WP_Query sets 'meta_value' = '' by default
-		if ( isset( $qv[ 'meta_value' ] ) && '' !== $qv[ 'meta_value' ] && ( ! is_array( $qv[ 'meta_value' ] ) || $qv[ 'meta_value' ] ) )
+		// WP_Query sets 'meta_value' = '' by default.
-			$meta_query[0]['value'] = $qv[ 'meta_value' ];
+		if ( isset( $qv['meta_value'] ) && '' !== $qv['meta_value'] && ( ! is_array( $qv['meta_value'] ) || $qv['meta_value'] ) ) {
+			$primary_meta_query['value'] = $qv['meta_value'];
-		if ( !empty( $qv['meta_query'] ) && is_array( $qv['meta_query'] ) ) {
+		}
-			$meta_query = array_merge( $meta_query, $qv['meta_query'] );
+		$existing_meta_query = isset( $qv['meta_query'] ) && is_array( $qv['meta_query'] ) ? $qv['meta_query'] : array();
+		if ( ! empty( $primary_meta_query ) && ! empty( $existing_meta_query ) ) {
+			$meta_query = array(
+				'relation' => 'AND',
+				$primary_meta_query,
+				$existing_meta_query,
+			);
+		} elseif ( ! empty( $primary_meta_query ) ) {
+			$meta_query = array(
+				$primary_meta_query,
+			);
+		} elseif ( ! empty( $existing_meta_query ) ) {
+			$meta_query = $existing_meta_query;
 		}
 		$this->__construct( $meta_query );
 	}
 	/**
-	 * Given a meta type, return the appropriate alias if applicable
+	 * Return the appropriate alias for the given meta type if applicable.
 	 *
 	 * @since 3.7.0
-	 *
+	 * @access public
-	 * @param string $type MySQL type to cast meta_value
+	 *
-	 * @return string MySQL type
+	 * @param string $type MySQL type to cast meta_value.
-	 */
+	 * @return string MySQL type.
-	function get_cast_for_type( $type = '' ) {
+	 */
+	public function get_cast_for_type( $type = '' ) {
 		if ( empty( $type ) )
 			return 'CHAR';
 		$meta_type = strtoupper( $type );
-		if ( ! in_array( $meta_type, array( 'BINARY', 'CHAR', 'DATE', 'DATETIME', 'DECIMAL', 'SIGNED', 'TIME', 'UNSIGNED', 'NUMERIC' ) ) )
+		if ( ! preg_match( '/^(?:BINARY|CHAR|DATE|DATETIME|SIGNED|UNSIGNED|TIME|NUMERIC(?:\(\d+(?:,\s?\d+)?\))?|DECIMAL(?:\(\d+(?:,\s?\d+)?\))?)$/', $meta_type ) )
 			return 'CHAR';
 		if ( 'NUMERIC' == $meta_type )
 			$meta_type = 'SIGNED';
 	 * Generates SQL clauses to be appended to a main query.
 	 *
 	 * @since 3.2.0
 	 * @access public
 	 *
-	 * @param string $type Type of meta
+	 * @param string $type              Type of meta, eg 'user', 'post'.
-	 * @param string $primary_table
+	 * @param string $primary_table     Database table where the object being filtered is stored (eg wp_users).
-	 * @param string $primary_id_column
+	 * @param string $primary_id_column ID column for the filtered object in $primary_table.
-	 * @param object $context (optional) The main query object
+	 * @param object $context           Optional. The main query object.
-	 * @return array( 'join' => $join_sql, 'where' => $where_sql )
+	 * @return array {
-	 */
+	 *     Array containing JOIN and WHERE SQL clauses to append to the main query.
-	function get_sql( $type, $primary_table, $primary_id_column, $context = null ) {
+	 *
+	 *     @type string $join  SQL fragment to append to the main JOIN clause.
+	 *     @type string $where SQL fragment to append to the main WHERE clause.
+	 * }
+	 */
+	public function get_sql( $type, $primary_table, $primary_id_column, $context = null ) {
+		if ( ! $meta_table = _get_meta_table( $type ) ) {
+			return false;
+		}
+		$this->meta_table     = $meta_table;
+		$this->meta_id_column = sanitize_key( $type . '_id' );
+		$this->primary_table     = $primary_table;
+		$this->primary_id_column = $primary_id_column;
+		$sql = $this->get_sql_clauses();
+		/*
+		 * If any JOINs are LEFT JOINs (as in the case of NOT EXISTS), then all JOINs should
+		 * be LEFT. Otherwise posts with no metadata will be excluded from results.
+		 */
+		if ( false !== strpos( $sql['join'], 'LEFT JOIN' ) ) {
+			$sql['join'] = str_replace( 'INNER JOIN', 'LEFT JOIN', $sql['join'] );
+		}
+		/**
+		 * Filter the meta query's generated SQL.
+		 *
+		 * @since 3.1.0
+		 *
+		 * @param array $args {
+		 *     An array of meta query SQL arguments.
+		 *
+		 *     @type array  $clauses           Array containing the query's JOIN and WHERE clauses.
+		 *     @type array  $queries           Array of meta queries.
+		 *     @type string $type              Type of meta.
+		 *     @type string $primary_table     Primary table.
+		 *     @type string $primary_id_column Primary column ID.
+		 *     @type object $context           The main query object.
+		 * }
+		 */
+		return apply_filters_ref_array( 'get_meta_sql', array( $sql, $this->queries, $type, $primary_table, $primary_id_column, $context ) );
+	}
+	/**
+	 * Generate SQL clauses to be appended to a main query.
+	 *
+	 * Called by the public {@see WP_Meta_Query::get_sql()}, this method
+	 * is abstracted out to maintain parity with the other Query classes.
+	 *
+	 * @since 4.1.0
+	 * @access protected
+	 *
+	 * @return array {
+	 *     Array containing JOIN and WHERE SQL clauses to append to the main query.
+	 *
+	 *     @type string $join  SQL fragment to append to the main JOIN clause.
+	 *     @type string $where SQL fragment to append to the main WHERE clause.
+	 * }
+	 */
+	protected function get_sql_clauses() {
+		/*
+		 * $queries are passed by reference to get_sql_for_query() for recursion.
+		 * To keep $this->queries unaltered, pass a copy.
+		 */
+		$queries = $this->queries;
+		$sql = $this->get_sql_for_query( $queries );
+		if ( ! empty( $sql['where'] ) ) {
+			$sql['where'] = ' AND ' . $sql['where'];
+		}
+		return $sql;
+	}
+	/**
+	 * Generate SQL clauses for a single query array.
+	 *
+	 * If nested subqueries are found, this method recurses the tree to
+	 * produce the properly nested SQL.
+	 *
+	 * @since 4.1.0
+	 * @access protected
+	 *
+	 * @param array $query Query to parse, passed by reference.
+	 * @param int   $depth Optional. Number of tree levels deep we currently are.
+	 *                     Used to calculate indentation. Default 0.
+	 * @return array {
+	 *     Array containing JOIN and WHERE SQL clauses to append to a single query array.
+	 *
+	 *     @type string $join  SQL fragment to append to the main JOIN clause.
+	 *     @type string $where SQL fragment to append to the main WHERE clause.
+	 * }
+	 */
+	protected function get_sql_for_query( &$query, $depth = 0 ) {
+		$sql_chunks = array(
+			'join'  => array(),
+			'where' => array(),
+		);
+		$sql = array(
+			'join'  => '',
+			'where' => '',
+		);
+		$indent = '';
+		for ( $i = 0; $i < $depth; $i++ ) {
+			$indent .= "  ";
+		}
+		foreach ( $query as $key => &$clause ) {
+			if ( 'relation' === $key ) {
+				$relation = $query['relation'];
+			} elseif ( is_array( $clause ) ) {
+				// This is a first-order clause.
+				if ( $this->is_first_order_clause( $clause ) ) {
+					$clause_sql = $this->get_sql_for_clause( $clause, $query, $key );
+					$where_count = count( $clause_sql['where'] );
+					if ( ! $where_count ) {
+						$sql_chunks['where'][] = '';
+					} elseif ( 1 === $where_count ) {
+						$sql_chunks['where'][] = $clause_sql['where'][0];
+					} else {
+						$sql_chunks['where'][] = '( ' . implode( ' AND ', $clause_sql['where'] ) . ' )';
+					}
+					$sql_chunks['join'] = array_merge( $sql_chunks['join'], $clause_sql['join'] );
+				// This is a subquery, so we recurse.
+				} else {
+					$clause_sql = $this->get_sql_for_query( $clause, $depth + 1 );
+					$sql_chunks['where'][] = $clause_sql['where'];
+					$sql_chunks['join'][]  = $clause_sql['join'];
+				}
+			}
+		}
+		// Filter to remove empties.
+		$sql_chunks['join']  = array_filter( $sql_chunks['join'] );
+		$sql_chunks['where'] = array_filter( $sql_chunks['where'] );
+		if ( empty( $relation ) ) {
+			$relation = 'AND';
+		}
+		// Filter duplicate JOIN clauses and combine into a single string.
+		if ( ! empty( $sql_chunks['join'] ) ) {
+			$sql['join'] = implode( ' ', array_unique( $sql_chunks['join'] ) );
+		}
+		// Generate a single WHERE clause with proper brackets and indentation.
+		if ( ! empty( $sql_chunks['where'] ) ) {
+			$sql['where'] = '( ' . "\n  " . $indent . implode( ' ' . "\n  " . $indent . $relation . ' ' . "\n  " . $indent, $sql_chunks['where'] ) . "\n" . $indent . ')';
+		}
+		return $sql;
+	}
+	/**
+	 * Generate SQL JOIN and WHERE clauses for a first-order query clause.
+	 *
+	 * "First-order" means that it's an array with a 'key' or 'value'.
+	 *
+	 * @since 4.1.0
+	 * @access public
+	 *
+	 * @param array  $clause       Query clause, passed by reference.
+	 * @param array  $parent_query Parent query array.
+	 * @param string $clause_key   Optional. The array key used to name the clause in the original `$meta_query`
+	 *                             parameters. If not provided, a key will be generated automatically.
+	 * @return array {
+	 *     Array containing JOIN and WHERE SQL clauses to append to a first-order query.
+	 *
+	 *     @type string $join  SQL fragment to append to the main JOIN clause.
+	 *     @type string $where SQL fragment to append to the main WHERE clause.
+	 * }
+	 */
+	public function get_sql_for_clause( &$clause, $parent_query, $clause_key = '' ) {
 		global $wpdb;
-		if ( ! $meta_table = _get_meta_table( $type ) )
+		$sql_chunks = array(
-			return false;
+			'where' => array(),
+			'join' => array(),
-		$meta_id_column = sanitize_key( $type . '_id' );
+		);
-		$join = array();
+		if ( isset( $clause['compare'] ) ) {
-		$where = array();
+			$clause['compare'] = strtoupper( $clause['compare'] );
+		} else {
-		$key_only_queries = array();
+			$clause['compare'] = isset( $clause['value'] ) && is_array( $clause['value'] ) ? 'IN' : '=';
-		$queries = array();
+		}
-		// Split out the queries with empty arrays as value
+		if ( ! in_array( $clause['compare'], array(
-		foreach ( $this->queries as $k => $q ) {
+			'=', '!=', '>', '>=', '<', '<=',
-			if ( isset( $q['value'] ) && is_array( $q['value'] ) && empty( $q['value'] ) ) {
+			'LIKE', 'NOT LIKE',
-				$key_only_queries[$k] = $q;
+			'IN', 'NOT IN',
-				unset( $this->queries[$k] );
+			'BETWEEN', 'NOT BETWEEN',
+			'EXISTS', 'NOT EXISTS',
+			'REGEXP', 'NOT REGEXP', 'RLIKE'
+		) ) ) {
+			$clause['compare'] = '=';
+		}
+		$meta_compare = $clause['compare'];
+		// First build the JOIN clause, if one is required.
+		$join = '';
+		// We prefer to avoid joins if possible. Look for an existing join compatible with this clause.
+		$alias = $this->find_compatible_table_alias( $clause, $parent_query );
+		if ( false === $alias ) {
+			$i = count( $this->table_aliases );
+			$alias = $i ? 'mt' . $i : $this->meta_table;
+			// JOIN clauses for NOT EXISTS have their own syntax.
+			if ( 'NOT EXISTS' === $meta_compare ) {
+				$join .= " LEFT JOIN $this->meta_table";
+				$join .= $i ? " AS $alias" : '';
+				$join .= $wpdb->prepare( " ON ($this->primary_table.$this->primary_id_column = $alias.$this->meta_id_column AND $alias.meta_key = %s )", $clause['key'] );
+			// All other JOIN clauses.
+			} else {
+				$join .= " INNER JOIN $this->meta_table";
+				$join .= $i ? " AS $alias" : '';
+				$join .= " ON ( $this->primary_table.$this->primary_id_column = $alias.$this->meta_id_column )";
 			}
-		}
+			$this->table_aliases[] = $alias;
-		// Split out the meta_key only queries (we can only do this for OR)
+			$sql_chunks['join'][] = $join;
-		if ( 'OR' == $this->relation ) {
+		}
-			foreach ( $this->queries as $k => $q ) {
-				if ( ! isset( $q['value'] ) && ! empty( $q['key'] ) )
+		// Save the alias to this clause, for future siblings to find.
-					$key_only_queries[$k] = $q;
+		$clause['alias'] = $alias;
-				else
-					$queries[$k] = $q;
+		// Determine the data type.
+		$_meta_type = isset( $clause['type'] ) ? $clause['type'] : '';
+		$meta_type  = $this->get_cast_for_type( $_meta_type );
+		$clause['cast'] = $meta_type;
+		// Fallback for clause keys is the table alias.
+		if ( ! $clause_key ) {
+			$clause_key = $clause['alias'];
+		}
+		// Ensure unique clause keys, so none are overwritten.
+		$iterator = 1;
+		$clause_key_base = $clause_key;
+		while ( isset( $this->clauses[ $clause_key ] ) ) {
+			$clause_key = $clause_key_base . '-' . $iterator;
+			$iterator++;
+		}
+		// Store the clause in our flat array.
+		$this->clauses[ $clause_key ] =& $clause;
+		// Next, build the WHERE clause.
+		// meta_key.
+		if ( array_key_exists( 'key', $clause ) ) {
+			if ( 'NOT EXISTS' === $meta_compare ) {
+				$sql_chunks['where'][] = $alias . '.' . $this->meta_id_column . ' IS NULL';
+			} else {
+				$sql_chunks['where'][] = $wpdb->prepare( "$alias.meta_key = %s", trim( $clause['key'] ) );
 			}
-		} else {
+		}
-			$queries = $this->queries;
-		}
+		// meta_value.
+		if ( array_key_exists( 'value', $clause ) ) {
-		// Specify all the meta_key only queries in one go
+			$meta_value = $clause['value'];
-		if ( $key_only_queries ) {
-			$join[]  = "INNER JOIN $meta_table ON $primary_table.$primary_id_column = $meta_table.$meta_id_column";
-			foreach ( $key_only_queries as $key => $q )
-				$where["key-only-$key"] = $wpdb->prepare( "$meta_table.meta_key = %s", trim( $q['key'] ) );
-		}
-		foreach ( $queries as $k => $q ) {
-			$meta_key = isset( $q['key'] ) ? trim( $q['key'] ) : '';
-			$meta_type = $this->get_cast_for_type( isset( $q['type'] ) ? $q['type'] : '' );
-			$meta_value = isset( $q['value'] ) ? $q['value'] : null;
-			if ( isset( $q['compare'] ) )
-				$meta_compare = strtoupper( $q['compare'] );
-			else
-				$meta_compare = is_array( $meta_value ) ? 'IN' : '=';
-			if ( ! in_array( $meta_compare, array(
-				'=', '!=', '>', '>=', '<', '<=',
-				'LIKE', 'NOT LIKE',
-				'IN', 'NOT IN',
-				'BETWEEN', 'NOT BETWEEN',
-				'NOT EXISTS',
-				'REGEXP', 'NOT REGEXP', 'RLIKE'
-			) ) )
-				$meta_compare = '=';
-			$i = count( $join );
-			$alias = $i ? 'mt' . $i : $meta_table;
-			if ( 'NOT EXISTS' == $meta_compare ) {
-				$join[$i]  = "LEFT JOIN $meta_table";
-				$join[$i] .= $i ? " AS $alias" : '';
-				$join[$i] .= " ON ($primary_table.$primary_id_column = $alias.$meta_id_column AND $alias.meta_key = '$meta_key')";
-				$where[$k] = ' ' . $alias . '.' . $meta_id_column . ' IS NULL';
-				continue;
-			}
-			$join[$i]  = "INNER JOIN $meta_table";
-			$join[$i] .= $i ? " AS $alias" : '';
-			$join[$i] .= " ON ($primary_table.$primary_id_column = $alias.$meta_id_column)";
-			$where[$k] = '';
-			if ( !empty( $meta_key ) )
-				$where[$k] = $wpdb->prepare( "$alias.meta_key = %s", $meta_key );
-			if ( is_null( $meta_value ) ) {
-				if ( empty( $where[$k] ) )
-					unset( $join[$i] );
-				continue;
-			}
 			if ( in_array( $meta_compare, array( 'IN', 'NOT IN', 'BETWEEN', 'NOT BETWEEN' ) ) ) {
-				if ( ! is_array( $meta_value ) )
+				if ( ! is_array( $meta_value ) ) {
 					$meta_value = preg_split( '/[,\s]+/', $meta_value );
-				if ( empty( $meta_value ) ) {
-					unset( $join[$i] );
-					continue;
 				}
 			} else {
 				$meta_value = trim( $meta_value );
 			}
-			if ( 'IN' == substr( $meta_compare, -2) ) {
+			switch ( $meta_compare ) {
-				$meta_compare_string = '(' . substr( str_repeat( ',%s', count( $meta_value ) ), 1 ) . ')';
+				case 'IN' :
-			} elseif ( 'BETWEEN' == substr( $meta_compare, -7) ) {
+				case 'NOT IN' :
-				$meta_value = array_slice( $meta_value, 0, 2 );
+					$meta_compare_string = '(' . substr( str_repeat( ',%s', count( $meta_value ) ), 1 ) . ')';
-				$meta_compare_string = '%s AND %s';
+					$where = $wpdb->prepare( $meta_compare_string, $meta_value );
-			} elseif ( 'LIKE' == substr( $meta_compare, -4 ) ) {
+					break;
-				$meta_value = '%' . like_escape( $meta_value ) . '%';
-				$meta_compare_string = '%s';
+				case 'BETWEEN' :
-			} else {
+				case 'NOT BETWEEN' :
-				$meta_compare_string = '%s';
+					$meta_value = array_slice( $meta_value, 0, 2 );
+					$where = $wpdb->prepare( '%s AND %s', $meta_value );
+					break;
+				case 'LIKE' :
+				case 'NOT LIKE' :
+					$meta_value = '%' . $wpdb->esc_like( $meta_value ) . '%';
+					$where = $wpdb->prepare( '%s', $meta_value );
+					break;
+				// EXISTS with a value is interpreted as '='.
+				case 'EXISTS' :
+					$meta_compare = '=';
+					$where = $wpdb->prepare( '%s', $meta_value );
+					break;
+				// 'value' is ignored for NOT EXISTS.
+				case 'NOT EXISTS' :
+					$where = '';
+					break;
+				default :
+					$where = $wpdb->prepare( '%s', $meta_value );
+					break;
 			}
-			if ( ! empty( $where[$k] ) )
+			if ( $where ) {
-				$where[$k] .= ' AND ';
+				$sql_chunks['where'][] = "CAST($alias.meta_value AS {$meta_type}) {$meta_compare} {$where}";
+			}
-			$where[$k] = ' (' . $where[$k] . $wpdb->prepare( "CAST($alias.meta_value AS {$meta_type}) {$meta_compare} {$meta_compare_string})", $meta_value );
+		}
-		}
+		/*
-		$where = array_filter( $where );
+		 * Multiple WHERE clauses (for meta_key and meta_value) should
+		 * be joined in parentheses.
-		if ( empty( $where ) )
+		 */
-			$where = '';
+		if ( 1 < count( $sql_chunks['where'] ) ) {
-		else
+			$sql_chunks['where'] = array( '( ' . implode( ' AND ', $sql_chunks['where'] ) . ' )' );
-			$where = ' AND (' . implode( "\n{$this->relation} ", $where ) . ' )';
+		}
-		$join = implode( "\n", $join );
+		return $sql_chunks;
-		if ( ! empty( $join ) )
+	}
-			$join = ' ' . $join;
+	/**
-		return apply_filters_ref_array( 'get_meta_sql', array( compact( 'join', 'where' ), $this->queries, $type, $primary_table, $primary_id_column, $context ) );
+	 * Get a flattened list of sanitized meta clauses.
+	 *
+	 * This array should be used for clause lookup, as when the table alias and CAST type must be determined for
+	 * a value of 'orderby' corresponding to a meta clause.
+	 *
+	 * @since 4.2.0
+	 * @access public
+	 *
+	 * @return array Meta clauses.
+	 */
+	public function get_clauses() {
+		return $this->clauses;
+	}
+	/**
+	 * Identify an existing table alias that is compatible with the current
+	 * query clause.
+	 *
+	 * We avoid unnecessary table joins by allowing each clause to look for
+	 * an existing table alias that is compatible with the query that it
+	 * needs to perform.
+	 *
+	 * An existing alias is compatible if (a) it is a sibling of `$clause`
+	 * (ie, it's under the scope of the same relation), and (b) the combination
+	 * of operator and relation between the clauses allows for a shared table join.
+	 * In the case of {@see WP_Meta_Query}, this only applies to 'IN' clauses that
+	 * are connected by the relation 'OR'.
+	 *
+	 * @since 4.1.0
+	 * @access protected
+	 *
+	 * @param  array       $clause       Query clause.
+	 * @param  array       $parent_query Parent query of $clause.
+	 * @return string|bool Table alias if found, otherwise false.
+	 */
+	protected function find_compatible_table_alias( $clause, $parent_query ) {
+		$alias = false;
+		foreach ( $parent_query as $sibling ) {
+			// If the sibling has no alias yet, there's nothing to check.
+			if ( empty( $sibling['alias'] ) ) {
+				continue;
+			}
+			// We're only interested in siblings that are first-order clauses.
+			if ( ! is_array( $sibling ) || ! $this->is_first_order_clause( $sibling ) ) {
+				continue;
+			}
+			$compatible_compares = array();
+			// Clauses connected by OR can share joins as long as they have "positive" operators.
+			if ( 'OR' === $parent_query['relation'] ) {
+				$compatible_compares = array( '=', 'IN', 'BETWEEN', 'LIKE', 'REGEXP', 'RLIKE', '>', '>=', '<', '<=' );
+			// Clauses joined by AND with "negative" operators share a join only if they also share a key.
+			} elseif ( isset( $sibling['key'] ) && isset( $clause['key'] ) && $sibling['key'] === $clause['key'] ) {
+				$compatible_compares = array( '!=', 'NOT IN', 'NOT LIKE' );
+			}
+			$clause_compare  = strtoupper( $clause['compare'] );
+			$sibling_compare = strtoupper( $sibling['compare'] );
+			if ( in_array( $clause_compare, $compatible_compares ) && in_array( $sibling_compare, $compatible_compares ) ) {
+				$alias = $sibling['alias'];
+				break;
+			}
+		}
+		/**
+		 * Filter the table alias identified as compatible with the current clause.
+		 *
+		 * @since 4.1.0
+		 *
+		 * @param string|bool $alias        Table alias, or false if none was found.
+		 * @param array       $clause       First-order query clause.
+		 * @param array       $parent_query Parent of $clause.
+		 * @param object      $this         WP_Meta_Query object.
+		 */
+		return apply_filters( 'meta_query_find_compatible_table_alias', $alias, $clause, $parent_query, $this ) ;
 	}
 }
 /**
 * Retrieve the name of the metadata table for the specified object type.
 *
 * @since 2.9.0
-* @uses $wpdb WordPress database object for queries.
+*
+* @global wpdb $wpdb WordPress database abstraction object.
 *
 * @param string $type Type of object to get metadata table for (e.g., comment, post, or user)
 * @return mixed Metadata table name, or false if no metadata table exists
 */
 function _get_meta_table($type) {
 	return $wpdb->$table_name;
 }
 /**
-* Determine whether a meta key is protected
+* Determine whether a meta key is protected.
 *
 * @since 3.1.3
 *
-* @param string $meta_key Meta key
+* @param string      $meta_key Meta key
+* @param string|null $meta_type
 * @return bool True if the key is protected, false otherwise.
 */
 function is_protected_meta( $meta_key, $meta_type = null ) {
 	$protected = ( '_' == $meta_key[0] );
+	/**
+	 * Filter whether a meta key is protected.
+	 *
+	 * @since 3.2.0
+	 *
+	 * @param bool   $protected Whether the key is protected. Default false.
+	 * @param string $meta_key  Meta key.
+	 * @param string $meta_type Meta type.
+	 */
 	return apply_filters( 'is_protected_meta', $protected, $meta_key, $meta_type );
 }
 /**
-* Sanitize meta value
+* Sanitize meta value.
 *
 * @since 3.1.3
 *
 * @param string $meta_key Meta key
 * @param mixed $meta_value Meta value to sanitize
 * @param string $meta_type Type of meta
 * @return mixed Sanitized $meta_value
 */
 function sanitize_meta( $meta_key, $meta_value, $meta_type ) {
+	/**
+	 * Filter the sanitization of a specific meta key of a specific meta type.
+	 *
+	 * The dynamic portions of the hook name, `$meta_type`, and `$meta_key`,
+	 * refer to the metadata object type (comment, post, or user) and the meta
+	 * key value,
+	 * respectively.
+	 *
+	 * @since 3.3.0
+	 *
+	 * @param mixed  $meta_value Meta value to sanitize.
+	 * @param string $meta_key   Meta key.
+	 * @param string $meta_type  Meta type.
+	 */
 	return apply_filters( "sanitize_{$meta_type}_meta_{$meta_key}", $meta_value, $meta_key, $meta_type );
 }
 /**
 * Register meta key
 *
 * @param string $meta_type Type of meta
 * @param string $meta_key Meta key
 * @param string|array $sanitize_callback A function or method to call when sanitizing the value of $meta_key.
 * @param string|array $auth_callback Optional. A function or method to call when performing edit_post_meta, add_post_meta, and delete_post_meta capability checks.
-* @param array $args Arguments
 */
 function register_meta( $meta_type, $meta_key, $sanitize_callback, $auth_callback = null ) {
 	if ( is_callable( $sanitize_callback ) )
 		add_filter( "sanitize_{$meta_type}_meta_{$meta_key}", $sanitize_callback, 10, 3 );

changeset 5	5e2f62d02dcd
parent 0	d970ebf37754
child 7	cf61fcea0001