/**
* Returns the revision with the given id.
*
* @param UUID $uuid
* @return AbstractRevision|null null if there is no such revision
*/
public function getRevision(UUID $uuid)
{
// check if fetching last already res
if (isset($this->revisions[$uuid->getAlphadecimal()])) {
return $this->revisions[$uuid->getAlphadecimal()];
}
/*
* The strategy here is to avoid having to call getAllRevisions(), which
* is most likely to have to load (fresh) data that is not yet in
* LocalBufferedCache's internal cache.
* To do so, we'll build the $this->revisions array by hand. Starting at
* the most recent revision and going up 1 revision at a time, checking
* if it is already in LocalBufferedCache's cache.
* If, however, we can't find the requested revisions (or one of the
* revisions on our way to the requested revision) in the internal cache
* of LocalBufferedCache, we'll just bail and load all revisions after
* all: if we do have to fetch data, might as well do it all in 1 go!
*/
while (!$this->loaded()) {
// fetch current oldest revision
$oldest = $this->getOldestLoaded();
// fetch that one's preceding revision id
$previousId = $oldest->getPrevRevisionId();
// check if it's in local storage already
if ($previousId && $this->getStorage()->got($previousId)) {
$revision = $this->getStorage()->get($previousId);
// add this revision to revisions array
$this->revisions[$previousId->getAlphadecimal()] = $revision;
// stop iterating if we've found the one we wanted
if ($uuid->equals($previousId)) {
break;
}
} else {
// revision not found in local storage: load all revisions
$this->getAllRevisions();
break;
}
}
if (!isset($this->revisions[$uuid->getAlphadecimal()])) {
return null;
}
return $this->revisions[$uuid->getAlphadecimal()];
}
