The MT worker previously reported errors through one C callback and left a
combined C finish callback responsible for serial completion, private resource
release, output-size publication, consumed-size publication, and signaling.
That kept the branch and lifecycle policy on the C side of the existing Rust
stage scheduler.
Add a narrow finish projection whose C callbacks expose only those private
leaves and the source-size scalar. Rust now publishes an error before serial
completion on every failed resource or codec stage, releases the sequence and
CCtx resources in the original order, publishes the final block size only on
success, then publishes the consumed size and signals the job condition. The
failed path therefore normalizes any codec-reported last-block size to zero
without changing the C-owned mutex, descriptor, pool, or context layouts.
Focused tests cover successful final-block publication, resource failure,
codec failure, cleanup ordering, consumed-size publication, and error-path
normalization.
Test Plan:
- `rustfmt --check --edition 2021 rust/src/zstdmt_compress.rs` -- passed
- `cc -fsyntax-only -Werror=incompatible-pointer-types -Ilib -Ilib/common -Ilib/compress -Ilib/decompress -Ilib/dict -Ilib/legacy lib/compress/zstdmt_compress.c` -- passed
- `git diff --check -- lib/compress/zstdmt_compress.c rust/src/zstdmt_compress.rs` and `git diff --cached --check` -- passed
- Rust unit tests were added but not run because the request prohibited Cargo and heavy commands
ddidderr
28a74c5edb