Every shared-message entry point has an *_in(&dyn Storage, ..) core:
message_data(_with_sohm), resolve_shared_message(_with_sohm),
resolve_sohm_message, load_sohm_table, and the SMTB/SMLI parsers, which
read the signature and then all entries in one bounded read (the list's
open-ended &file_data[pos..] slice is gone). Object headers and the SOHM
fractal heap are read through their Storage parsers; a SOHM B-tree index
still needs the v2 B-tree over a slice, so over a backend without one it
is a clean ContiguousStorageRequired error. New signature::find_signature_in
probes the candidate offsets with 8-byte reads. The &[u8] functions are
wrappers.
New tests: SOHM tables and lists with 4- and 8-byte offsets, at two
offsets, cut at every length and with a bad signature, parse identically
through a read_at-only CountingStorage in at most two reads; the
signature search matches the slice search.
Co-Authored-By: Claude Opus 5.5 (1M context) <[email protected]>
