BP_XProfile_Field::get_member_types()

	public function get_member_types() {
		if ( ! is_null( $this->member_types ) ) {
			return $this->member_types;
		}

		$raw_types = bp_xprofile_get_meta( $this->id, 'field', 'member_type', false );

		// If `$raw_types` is not an array, it probably means this is a new field (id=0).
		if ( ! is_array( $raw_types ) ) {
			$raw_types = array();
		}

		// If '_none' is found in the array, it overrides all types.
		$types = array();
		if ( ! in_array( '_none', $raw_types ) ) {
			$registered_types = bp_get_member_types();

			// Eliminate invalid profile types saved in the database.
			foreach ( $raw_types as $raw_type ) {
				// 'null' is a special case - it represents users without a type.
				if ( 'null' === $raw_type || isset( $registered_types[ $raw_type ] ) ) {
					$types[] = $raw_type;
				}
			}

			// If no profile types have been saved, intepret as *all* profile types.
			if ( empty( $types ) ) {
				$types = array_values( $registered_types );

				// + the "null" type, ie users without a type.
				$types[] = 'null';
			}
		}

		/**
		 * Filters the profile types to which an XProfile object should be applied.
		 *
		 * @since BuddyPress 2.4.0
		 *
		 * @param array $types profile types.
		 * @param BP_XProfile_Field $field Field object.
		 */
		$this->member_types = apply_filters( 'bp_xprofile_field_member_types', $types, $this );

		return $this->member_types;
	}