/**
* Sync $dst backend to $src backend based on the $src logs given after $start.
* Returns the journal entry ID this advanced to and handled (inclusive).
*
* @param FileBackend $src
* @param FileBackend $dst
* @param int $start Starting journal position
* @param int $end Starting journal position
* @param Closure $callback Callback to update any position file
* @return int|bool Journal entry ID or false if there are none
*/
protected function syncBackends(FileBackend $src, FileBackend $dst, $start, $end, Closure $callback)
{
$lastOKPos = 0;
// failed
$first = true;
// first batch
if ($start > $end) {
// sanity
$this->error("Error: given starting ID greater than ending ID.", 1);
}
$next = null;
do {
$limit = min($this->mBatchSize, $end - $start + 1);
// don't go pass ending ID
$this->output("Doing id {$start} to " . ($start + $limit - 1) . "...\n");
$entries = $src->getJournal()->getChangeEntries($start, $limit, $next);
$start = $next;
// start where we left off next time
if ($first && !count($entries)) {
return false;
// nothing to do
}
$first = false;
$lastPosInBatch = 0;
$pathsInBatch = [];
// changed paths
foreach ($entries as $entry) {
if ($entry['op'] !== 'null') {
// null ops are just for reference
$pathsInBatch[$entry['path']] = 1;
// remove duplicates
}
$lastPosInBatch = $entry['id'];
}
$status = $this->syncFileBatch(array_keys($pathsInBatch), $src, $dst);
if ($status->isOK()) {
$lastOKPos = max($lastOKPos, $lastPosInBatch);
$callback($lastOKPos);
// update position file
} else {
$this->error(print_r($status->getErrorsArray(), true));
break;
// no gaps; everything up to $lastPos must be OK
}
if (!$start) {
$this->output("End of journal entries.\n");
}
} while ($start && $start <= $end);
return $lastOKPos;
}
