Cache scan folder result

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In 2.3,
unused file thread are removed after first prefetch.

I notice that the thread overhead is almost zero,
but Windows take vast of time to iterate through the file system and list all file.
This is much slower than expected.

Instead of scan all 26968 files, use a config array as cache?

[mhtvsSFrpHdE]

Information

https://stackoverflow.com/questions/1192951/quicker-quickest-way-to-get-number-of-files-in-a-directory-with-over-200-000

[mhtvsSFrpHdE]

Cache

Create cache

• Core\scan_cache.h, Core\scan_cache.cpp e18cb43
• Confirm or modify thread pool object to extract file path b191afc
• Save file path to cache after each scan c3f801b
  • [ScanFolder]
  • Generate key name use array index start from 0
  • Get setting ini name, cache name will be setting.cache.ini

Confirm cache exist 83abdda

• Bool function cache ini exist on disk (available)
• No support for fuzzy|damaged ini, use directly

Use cache 9ff27ef

• Before each scan, if cache available, use cache||skip scan
• Read array value and restore to read thread, to thread pool

Cache expire

• What is the cache expire rule? How about RescanInterval?
  • Ram variable cache_expired, cache_use_count, greater|equal to RescanInterval, true
  • Function to expire cache 25f4ac0