- src/mem.rs: MemBackend implements Backend (seven methods + put_staged,
name "mem") over Arc<parking_lot::Mutex<BTreeMap<..>>>; CAS
first-writer-wins puts, materializing MemCursor body, degenerate
in-memory MemStaging whose commit publishes via the same CAS clause
and self-discards on failure; discard leaves zero residue.
- CAS re-put is dedup for both put forms; reads are no-ops on the
virgin store; delete carries Missing; size is metadata-only.
- Eight in-module tests mirror the wave-1 double's assertions: method
contract, list well-formedness, cursor body read contract + ADR-006
range digest, empty-entry round-trip, staged happy path, and both
hygiene forms (fail_commit test hook stands in for media failure).
- backend.rs: clamped promoted pub(crate) — the shared EOF-clamping
arithmetic both mem cursor bodies compose (no per-engine duplicate).
Verification: cargo test --features mem (33+7 green); cargo test
(default) green; clippy --all-features --all-targets -D warnings green;
fmt --check green.
Nine tasks against the wave-1 contract surface as reviewed (no
amendments from the gate):
- engine-mem / engine-local (parallel, dependency-free): the two
engines; local owns the stage-hygiene exact-count tests and the
Drop-cancellation story the wave-1 review recorded
- store-construction: the Store type, constructor modes, size-threshold
dispatch; binds the conformance factory's Store associated type
- store-read-paths ∥ gc-protocol: read ops with the ADR-012 §6.1
fall-through rule; the ADR-005 in-process protocol (pins, liveness,
delete windows, abort-as-data, GcRefuse with the full protection set)
- store-put-paths: the two put paths behind one signature, ADR-003's
three numbered rules, pin-before-publish, Batch, kv-only rejection
- suite-column-mem → suite-column-local: the reference column, then the
dual-tier dispatch-coverage shape mirroring it
- review-wave-2: the gate (facade/dispatch/GC vs ADR-003/005/012)
Verification: dependency graph validated (all ids resolve, no cycles,
topological order clean); docs-only change.
Refs: docs/plans/implementation.md §Wave 2
glm-5.3-flash