- Public `(len, stream)` shape: `Store::get` returns
`Option<(u64, Blob)>`; `Blob` (src/facade.rs) is a bounded, re-entrant
windowed reader over the new crate-internal `AnyCursor` tier dispatch
(mem materializing / local pread body families) — engine cursors
never leak onto the surface; no chunk-iterator machinery.
- Verification-on-get pinned against ADR-006: kv-tier materialized
reads whole-blob hash-check at get time (mismatch = Err(Verification),
never a further fall-through); the large tier's streaming open is
metadata + handle only (put-path verification + slice digests are its
story); `read_range` carries slice digests only, on both tiers.
- `stat` rides the trait's `size` probe (never a content load) into
`EntryMeta { len, algorithm }`; `has` is the pure existence probe;
both fall through kv -> large like every key-addressed op (ADR-012
§6.1) — consult order, not routing (never consults `tier_for`).
- Miss shapes enforced (the error module's behavioral note): both-tier
misses are Ok(None) on get/stat, false on has, Err(Missing) on
read_range; `src/error.rs` wave-2 deferral notes updated to enforced
state.
- `list` decided Vec<Key>: materialized, sorted total-order union of
both tiers (the sweep consumes the engines' enumeration directly);
malformed pool bytes are fatal `Err(KeyInvalid)`, never a silent
skip.
- `KeyInvalid` at the facade boundary: ops take opaque key bytes and
convert via `Key::from_bytes` once (`boundary_key`); engines never
see typed keys.
- Twelve read-path tests: virgin-store shapes per mode (dual-tier,
mem-only, kv-only), the `(len, stream)` windows, fall-through,
kv-first (decoy content in the large tier), both verification
postures, list union/sort/pool-fatality, and malformed-key
rejection on every op.
Task: tasks/store-read-paths.md (design points recorded in Notes for
the wave-2 review gate).
Verification: cargo test (default), cargo test --features mem, cargo
test --all-features green; cargo clippy --all-targets -- -D warnings
green in all three feature shapes; cargo fmt --check green; cargo doc
--no-deps clean beyond the pre-existing private-intra-doc-links class.
The wave-2 facade skeleton and routing (tasks/store-construction.md):
the public surface consumers program against, with the ops methods
still to land against it in store-read-paths/gc-protocol/store-put-paths.
- src/store.rs — the public `Store` type (engine-blind, ADR-007/008/
010) over crate-internal tier enums (`KvEngine`{mem}, `LargeEngine`{
local}): the engine-representation design point decided as concrete
+ enum dispatch, generic rejected (pub(crate) engines, no dyn);
the three constructor modes as named constructors — `mem_only`,
`kv_only_mem`, `dual_tier_mem_local` (the ADR-012 §6.3
dispatch-coverage shape) — with `StoreMode` introspection; the
write-side routing seam (`tier_for`), the read-side fall-through
order (`kv()` then `large()`, ADR-012 §6.1), and the `GcHome`
GC-state field; the ADR-012 §3 fleet declaration ruled deferred to
the engine waves (nothing fleet-valid is constructible yet)
- src/dispatch.rs — the pure routing function (`route`, at-or-below
→ kv), `DEFAULT_DISPATCH_THRESHOLD` (128 KiB) exported at the
crate root, boundary-value unit tests (exactly-at-threshold,
degenerate tunings, purity)
- src/gc.rs — `GcHome`: the store-instance GC-state home the
gc-protocol task fills (in-process; fleet state stays on the
engine-state seam per ADR-010 §2/ADR-012 §4)
- tests/conformance — the wave-2 binding made as anticipated: the
factory's `Store` associated type collapsed into the concrete
`alkblobs::Store` (`open` vends it directly), recorded in
factory.rs + README; the wave-1 mock probe retired, replaced by
mem-gated binding demo factories (binding.rs) over both
constructible shapes
Verification: `cargo test` (default), `cargo test --features mem`,
`cargo test --all-features` green (41/53/53 unit + conformance
targets green in all three shapes); `cargo clippy --all-targets
-- -D warnings` green in all three feature shapes; `cargo fmt
--check` green; `cargo doc --no-deps` adds no warnings beyond the
pre-existing private-intra-doc-links class.
glm-5.3-flash