+ (file-dirs ; File names ever seen, with dirs.
+ (make-hash-table :size 2000 :test 'equal))
+ (true-names ; Dirs ever considered.
+ (make-hash-table :size 50 :test 'equal))
+ (files-seen-this-dir ; Files seen so far in this dir.
+ (make-hash-table :size 100 :test 'equal))
+ )