The ROUND23-deferred download_zip N+1, given its own validated pass. The
individually-selected files were authorized + fetched one at a time via
get_file_with_perms (require + get = 2 serial round-trips/file) before any
streaming — a 200-file selection was 400 serial round-trips. AFTER routes the
whole multi-select through the new
FileRetrievalService::get_files_by_ids_with_perms: one check_files_read_batch
(the PgAclEngine resolves every file's drive in ONE query and primes the
resource->drive cache) + one get_files_by_ids. 2N round-trips -> 2.
Authorization is unchanged and still enforced BEFORE any ZIP entry is written:
- add_file_entry_streamed writes the entry header (the filename) before it opens
the authorized stream, so the pre-filter is load-bearing — a denied file must
never reach it or its name leaks into the archive. AFTER a denied/missing id
is absent from the authorized map and is skipped in the same input order,
exactly as the old loop skipped a denied get_file_with_perms; it never reaches
the entry write. The authz moved from a per-file require to one batch check
EARLIER in the same function, not into or after the stream.
- The stream open keeps its own per-file Read check (now a primed-cache hit) +
Recents recording; check_files_read_batch is documented + gated as identical
to looping require.
Because the change is authorization-sensitive, the gate is the security property
itself. bench_round24_zip_authz drives the real PgAclEngine over a seeded,
interleaved mix of owned (granted drive) + denied (other drive) + missing ids
and asserts: the batch inclusion set AND input order are identical to the
per-file require loop; the included set is exactly the caller's owned files; no
denied or missing id is ever included (the authz-regression tripwire); and the
batch fetch returns exactly the owned files. Latency (cold, 600-item 1/3-owned
selection): 559 -> 267 ms (2.10x; the realistic all-owned selection is O(1) ->
a larger win). See benches/ROUND24.md.
The folder selections are left as-is (root counts are small and there is no
check_folders_read_batch primitive to batch through).
Verified: cargo clippy --features bench --all-targets -D warnings clean, cargo
fmt --all --check clean, cargo test --lib --features bench = 529 passed / 0
failed.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01DKyQ4AnYtgp1JtjzweyMeo
Claude
ffb536e0ae