/**
* Hashes a filename into the corresponding local directory, in a manner consistent with Spark's
* DiskBlockManager.getFile().
*/
@VisibleForTesting
static File getFile(String[] localDirs, int subDirsPerLocalDir, String filename) {
int hash = JavaUtils.nonNegativeHash(filename);
String localDir = localDirs[hash % localDirs.length];
int subDirId = (hash / localDirs.length) % subDirsPerLocalDir;
return new File(new File(localDir, String.format("%02x", subDirId)), filename);
}
