/**
* Given a certain revision, returns the previous revision.
*
* @param AbstractRevision $revision
* @return AbstractRevision|null null if there is no previous revision
*/
public function getPrevRevision(AbstractRevision $revision)
{
$previousRevisionId = $revision->getPrevRevisionId();
if (!$previousRevisionId) {
return null;
}
return $this->getRevision($previousRevisionId);
}
/**
* Generate a link to undo the specified revision. Note that this will only work if
* that is the most recent content edit against the revision type.
*
* @param AbstractRevision $revision The revision to undo.
* @param Title|null $title The title the revision belongs to
* @param UUID $workflowId The workflow id the revision belongs to
* @return Anchor
* @throws FlowException When the provided revision is not known
*/
public function undoAction(AbstractRevision $revision, Title $title = null, UUID $workflowId)
{
$startId = $revision->getPrevRevisionId();
$endId = $revision->getRevisionId();
if ($revision instanceof PostRevision) {
return $this->undoEditPostAction($title, $workflowId, $startId, $endId);
} elseif ($revision instanceof Header) {
return $this->undoEditHeaderAction($title, $workflowId, $startId, $endId);
} elseif ($revision instanceof PostSummary) {
return $this->undoEditSummaryAction($title, $workflowId, $startId, $endId);
} else {
throw new FlowException('Unknown revision type: ' . get_class($revision));
}
}
/**
* Retrieves the previous revision for a given AbstractRevision
* @param AbstractRevision $revision The revision to retrieve the previous revision for.
* @return AbstractRevision|null AbstractRevision of the previous revision or null if no previous revision.
*/
protected function getPreviousRevision(AbstractRevision $revision)
{
$previousRevisionId = $revision->getPrevRevisionId();
// original post; no previous revision
if ($previousRevisionId === null) {
return null;
}
if (!isset($this->revisionCache[$previousRevisionId->getAlphadecimal()])) {
$this->revisionCache[$previousRevisionId->getAlphadecimal()] = $this->storage->get('PostRevision', $previousRevisionId);
}
return $this->revisionCache[$previousRevisionId->getAlphadecimal()];
}