To get a revision from a Repository object:
$revision = $repository->getRevision('master@{2 days ago}');
You can access a Log object starting from a revision using the getLog method. This method takes two parameters: offset and limit:
// Returns 100 lasts commits
$log = $revision->getLog(null, 100);
To resolve a revision to a commit:
$commit = $revision->getCommit();