Generators are non rewindable by default, you can wrap them in this to make them rewindable.

RewindableGenerator.php

<?php

namespace Jenko;

/**
 * Usage:
 * $rewindableGenerator = new RewindableGenerator(function() {
 *    reset($this->cursor);
 *    while ($row = $this->fetch()) {
 *        yield $row;
 *    }
 *});
 */
class RewindableGenerator implements \IteratorAggregate
{
    private $generator;

    /**
     * @param callable $generator
     */
    public function __construct(callable $generator)
    {
        $this->generator = $generator;
    }

    public function getIterator()
    {
        return ($this->generator)();
    }
}