git.m6w6.name Git - m6w6/pq-gateway/blob - lib/pq/Gateway/Table/PessimisticLock.php

   1 <?php
   2
   3 namespace pq\Gateway\Table;
   4
   5 use \pq\Gateway\Row;
   6
   7 /**
   8  * A pessimistic row lock implementation using an additional SELECT FOR UPDATE
   9  */
  10 class PessimisticLock implements LockInterface
  11 {
  12         /**
  13          * @inheritdoc
  14          * @param \pq\Gateway\Row $row
  15          * @param array $ignore
  16          * @throws \UnexpectedValueException if the row has already been modified
  17          */
  18         function onUpdate(Row $row, array &$ignore) {
  19                 $where = array();
  20                 foreach ($row->getIdentity() as $col => $val) {
  21                         if (isset($val)) {
  22                                 $where["$col="] = $val;
  23                         } else {
  24                                 $where["$col IS"] = new QueryExpr("NULL");
  25                         }
  26                 }
  27
  28                 if (1 != count($rowset = $row->getTable()->find($where, null, 0, 0, "update nowait"))) {
  29                         throw new \UnexpectedValueException("Failed to select a single row");
  30                 }
  31                 if ($rowset->current()->getData() != $row->getData()) {
  32                         throw new \UnexpectedValueException("Row has already been modified");
  33                 }
  34         }
  35 }