3 namespace Wikimedia\Rdbms;
9 * Result wrapper for grabbing data queried from an IDatabase object
11 * Note that using the Iterator methods in combination with the non-Iterator
12 * DB result iteration functions may cause rows to be skipped or repeated.
14 * By default, this will use the iteration methods of the IDatabase handle if provided.
15 * Subclasses can override methods to make it solely work on the result resource instead.
16 * If no database is provided, and the subclass does not override the DB iteration methods,
17 * then a RuntimeException will be thrown when iteration is attempted.
19 * The result resource field should not be accessed from non-Database related classes.
20 * It is database class specific and is stored here to associate iterators with queries.
24 class ResultWrapper implements IResultWrapper {
25 /** @var resource|array|null Optional underlying result handle for subclass usage */
28 /** @var IDatabase|null */
33 /** @var stdClass|null */
34 protected $currentRow = null;
37 * Create a row iterator from a result resource and an optional Database object
39 * Only Database-related classes should construct ResultWrapper. Other code may
40 * use the FakeResultWrapper subclass for convenience or compatibility shims, however.
42 * @param IDatabase|null $db Optional database handle
43 * @param ResultWrapper|array|resource $result Optional underlying result handle
45 public function __construct( IDatabase $db = null, $result ) {
47 if ( $result instanceof ResultWrapper ) {
48 $this->result = $result->result;
50 $this->result = $result;
54 public function numRows() {
55 return $this->getDB()->numRows( $this );
58 public function fetchObject() {
59 return $this->getDB()->fetchObject( $this );
62 public function fetchRow() {
63 return $this->getDB()->fetchRow( $this );
66 public function seek( $row ) {
67 $this->getDB()->dataSeek( $this, $row );
70 public function free() {
72 $this->db->freeResult( $this );
80 * @throws RuntimeException
82 private function getDB() {
84 throw new RuntimeException( static::class . ' needs a DB handle for iteration.' );
91 if ( $this->numRows() ) {
92 $this->getDB()->dataSeek( $this, 0 );
95 $this->currentRow = null;
99 if ( is_null( $this->currentRow ) ) {
103 return $this->currentRow;
112 $this->currentRow = $this->fetchObject();
114 return $this->currentRow;
118 return $this->current() !== false;
122 class_alias( ResultWrapper::class, 'ResultWrapper' );