* @param handler a path handler
* @throws SVNException no repository is found at
* <code>repositoryRoot</code>
*/
public void doGetChangedDirectories(File repositoryRoot, SVNRevision revision, ISVNChangedDirectoriesHandler handler) throws SVNException {
FSFS fsfs = open(repositoryRoot, revision);
long revNum = SVNAdminHelper.getRevisionNumber(revision, fsfs.getYoungestRevision(), fsfs);
FSRoot root = fsfs.createRevisionRoot(revNum);
long baseRevision = revNum - 1;
SVNNodeEditor editor = generateDeltaTree(fsfs, root, baseRevision);
editor.traverseChangedDirs(handler);
}