Distinct from a scan, and the distinction is the whole reason the crate
exists: a scan catalogues files where they already are, where an import moves
them from a card into the library. A scan that fails halfway has read
nothing; an import that fails halfway has written something.
So the failure paths are the design. Bytes stream at 1 MiB and are hashed on
the way past, so an 80 MB RAW never sits in memory. The second destination
(FR-CAT-10's backup copy) is written from the same read rather than copied
from the primary afterwards — a backup made by re-reading the primary would
inherit a bad write rather than catch it, and re-reading the card doubles the
wear on the one copy that still exists. Verification re-reads the
destination, because hashing what is still in memory would pass on a full
disk, a dying card and a truncated write alike. Anything that fails past the
point of creating the file takes the file back, or the next scan catalogues a
truncated RAW as though it were fine.
Three things the crate refuses to know. It never deletes from the card: a
move-import records what is now redundant and a separate retire() does the
deleting, because on a syncing library "safe" means the upload was confirmed
(FR-NC-7b). It does not decode, so capture metadata arrives through a probe
and a card of unreadable files costs no demosaic. And it does not know what a
duplicate is, since that is a catalog query — FR-CAT-11's two tiers arrive as
one closure asked twice, once before any transfer and once with the digest.
Camera serial would be the stronger metadata key and is absent, because
nothing in the tree reads it yet; make and model plus capture time and the
original filename is what is available, and the digest tier covers the gap.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
dtourolleandClaude Opus 5
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