After D25335 has landed, we can envision several improvements
- Have a singleton thread and worker, so that no matter how many tabs and split views dolphin would have as much 1 worker making the disk spin.
- prioritize folders not yet in cache to be scanned first
- prevent duplicate in queue
- share the cache / implementation with the rest of dolphin (status bar text), this would possibly need some heavy refactoring
- share the cache / implementation with the FileMetadataWidget so it can show the same data, this would possibly need some heavy refactoring
CC @ngraham @elvisangelaccio