Memory Cache

Tue, 17 Mar 2026 00:00:00 +0000

Cache System — RawCull

RawCull uses a three-layer cache to avoid repeated RAW decoding. Decoding an ARW file on demand is expensive — the three-layer approach ensures that most requests are served from RAM or disk rather than from source.

Layers (fastest to slowest):

Memory cache — NSCache<NSURL, DiscardableThumbnail> in RAM
Disk cache — JPEG files on disk in ~/Library/Caches/no.blogspot.RawCull/Thumbnails/
Source decode — CGImageSourceCreateThumbnailAtIndex from the ARW file

The same cache stack is shared by two paths: the bulk preload flow (ScanAndCreateThumbnails) and on-demand per-file requests (RequestThumbnail).

Cache on RawCull

Memory Cache

Cache System — RawCull