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feat(decompress): move legacy stream dispatch to Rust

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Move the legacy buffered-stream dispatcher out of the C decompression adapter
while keeping ZSTD_DCtx_s private and C-owned. Rust now consumes the existing
ZSTD_rustDctxView projection, detects the legacy version at input.pos, preserves
static-context rejection and stream-stage reset behavior, and handles legacy
context replacement through the version-gated v0.4-v0.7 Rust stream APIs.

The Rust boundary retains the C helper's NULL normalization, dictionary
lifetime sentinel, previous-version cleanup semantics, input/output position
updates, and version-unsupported and no-legacy-support fallbacks. The C legacy
free helper remains unchanged; only the dispatcher declaration and body were
removed from the adapter. Focused tests cover unsupported versions, stage
reset, context reuse/switching, and partial v0.4 input/output progress.

Test Plan:
- `cargo clippy --manifest-path rust/Cargo.toml --no-default-features --features compression` -- passed
- Same clippy command with `--benches` and `--tests` -- passed
- `cargo +nightly fmt --manifest-path rust/Cargo.toml`, followed by all three clippy commands -- passed
- Decompression/legacy clippy with `-D warnings` -- passed
- All 107 Rust tests with v0.4-v0.7 features -- passed
- Focused legacy dispatcher tests: 4 passed
- `make -C lib -j2 lib-mt` and `make -C lib -j2 lib-nomt` -- passed
- `make -C tests -j2 test-legacy` -- built, then failed in the existing simple one-shot path with one v0.8 output byte mismatch (`e0` vs expected `e2`) before the streaming check; the new dispatcher symbol was not called on that failing path
This commit is contained in:
ddidderr
2026-07-18 15:05:10 +02:00
parent d00bcf7d06
commit 5157bab8a9
2 changed files with 428 additions and 51 deletions
Download Patch File Download Diff File Expand all files Collapse all files
lib/decompress/zstd_decompress.c
-44
View File
@@ -143,10 +143,6 @@ size_t ZSTD_rust_legacy_frame_size_info(const void* src, size_t srcSize,
size_t ZSTD_rust_legacy_decompress(void* dst, size_t dstCapacity,
const void* src, size_t srcSize,
const void* dict, size_t dictSize);
size_t ZSTD_rust_legacy_decompress_stream(ZSTD_DCtx* dctx,
ZSTD_outBuffer* output,
ZSTD_inBuffer* input,
const void* dict, size_t dictSize);
void ZSTD_rust_legacy_free_stream(ZSTD_DCtx* dctx);
void ZSTD_rust_dctx_view(ZSTD_DCtx* dctx, ZSTD_rustDctxView* out)
@@ -428,46 +424,6 @@ size_t ZSTD_rust_legacy_decompress(void* dst, size_t dstCapacity,
#endif
}
size_t ZSTD_rust_legacy_decompress_stream(ZSTD_DCtx* dctx,
ZSTD_outBuffer* output,
ZSTD_inBuffer* input,
const void* dict, size_t dictSize)
{
#if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT >= 1)
size_t hint;
if (dctx->legacyVersion) {
hint = ZSTD_decompressLegacyStream(dctx->legacyContext,
dctx->legacyVersion, output, input);
if (hint == 0) dctx->streamStage = zdss_init;
return hint;
}
{
const char* const istart = input->pos != 0
? (const char*)input->src + input->pos
: (const char*)input->src;
size_t const inputSize = input->size - input->pos;
U32 const legacyVersion = ZSTD_isLegacy(istart, inputSize);
if (!legacyVersion) return ERROR(prefix_unknown);
if (dctx->staticSize) return ERROR(memory_allocation);
FORWARD_IF_ERROR(ZSTD_initLegacyStream(&dctx->legacyContext,
dctx->previousLegacyVersion,
legacyVersion, dict, dictSize), "");
dctx->legacyVersion = dctx->previousLegacyVersion = legacyVersion;
hint = ZSTD_decompressLegacyStream(dctx->legacyContext, legacyVersion,
output, input);
if (hint == 0) dctx->streamStage = zdss_init;
return hint;
}
#else
(void)dctx;
(void)output;
(void)input;
(void)dict;
(void)dictSize;
return ERROR(prefix_unknown);
#endif
}
void ZSTD_rust_legacy_free_stream(ZSTD_DCtx* dctx)
{
#if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT >= 1)