/**
* @param callable|null $filter Accepts an array of objects found in a single query
* as its only argument and returns an array of accepted objects.
* @return PagerPage
*/
public function getPage($filter = null)
{
$numNeeded = $this->options['pager-limit'] + 1;
$options = $this->options + array('limit' => $numNeeded, 'offset-dir' => $this->options['pager-dir'], 'offset-id' => $this->options['pager-offset'], 'include-offset' => $this->options['pager-include-offset'], 'offset-elastic' => true);
$offset = $this->options['pager-offset'];
$results = array();
$queries = 0;
do {
if ($queries === 2) {
// if we hit a third query ask for more items
$options['limit'] = min(self::MAX_LIMIT, $this->options['pager-limit'] * 5);
}
// Retrieve results
$found = $this->storage->find($this->query, array('offset-id' => $offset) + $options);
if (!$found) {
// nothing found
break;
}
$filtered = $filter ? call_user_func($filter, $found) : $found;
if ($this->options['pager-dir'] === 'rev') {
// Paging A-Z with pager-offset F, pager-dir rev, pager-limit 2 gives
// DE on first query, BC on second, and A on third. The output
// needs to be ABCDE
$results = array_merge($filtered, $results);
} else {
$results = array_merge($results, $filtered);
}
if (count($found) !== $options['limit']) {
// last page
break;
}
// setup offset for next query
if ($this->options['pager-dir'] === 'rev') {
$last = reset($found);
} else {
$last = end($found);
}
$offset = $this->storage->serializeOffset($last, $this->sort);
} while (count($results) < $numNeeded && ++$queries < self::MAX_QUERIES);
if ($queries >= self::MAX_QUERIES) {
$count = count($results);
$limit = $this->options['pager-limit'];
wfDebugLog('Flow', __METHOD__ . "Reached maximum of {$queries} queries with {$count} results of {$limit} requested with query of " . json_encode($this->query) . ' and options ' . json_encode($options));
}
if ($results) {
return $this->processPage($results);
} else {
return new PagerPage(array(), array(), $this);
}
}
