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refactor(mt): move stream dictionary branch policy to Rust

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The MT stream initializer and its later dictionary update both encoded the
same three-way choice in C: copy a supplied dictionary, attach a borrowed
CDict, or install a raw prefix. The old code also embedded the required
release/clear-before-attach ordering in each callback wrapper. Project the
presence and raw-content flags into Rust, where the branch and ordering are
now explicit and tested. C retains only the private CDict allocation,
prefix-storage, context publication, and destruction callbacks, so the
configured C layouts and allocator behavior remain unchanged.

Test Plan:
- `ulimit -v 41943040; cargo +nightly fmt --manifest-path rust/Cargo.toml --all -- --check` -- passed
- `ulimit -v 41943040; CARGO_BUILD_JOBS=1 cargo clippy --manifest-path rust/Cargo.toml --all-targets -- -D warnings` -- passed
- `git diff --check` and `rustfmt --edition 2021 --check` -- passed before commit
- Capped native and original-test verification remains pending for the complete batch.
This commit is contained in:
ddidderr
2026-07-20 19:47:51 +02:00
parent ee6953b1d7
commit b0e90c39e2
2 changed files with 390 additions and 37 deletions
Download Patch File Download Diff File Expand all files Collapse all files
rust/src/zstdmt_compress.rs
+302 -6
View File
@@ -7,12 +7,13 @@
//!
//! The serial LDM state, job descriptor fields, worker callback, and streaming
//! state still use private C layouts. `zstdmt_compress.c` therefore keeps
//! those operations and projects only allocation/lifecycle pieces and pure
//! sizing policy into this module. The entry points below are narrow C ABIs:
//! buffers, `ZSTD_CCtx *` values, and job descriptors remain opaque to Rust,
//! while allocation, reuse, table-capacity orchestration, and sizing policy
//! are Rust-owned. C retains ownership of private descriptor fields and
//! platform synchronization.
//! those operations and projects allocation/lifecycle pieces, dictionary
//! transition policy, and pure sizing policy into this module. The entry
//! points below are narrow C ABIs: buffers, `ZSTD_CCtx *` values, and job
//! descriptors remain opaque to Rust, while allocation, reuse, table-capacity
//! orchestration, dictionary branch/order policy, and sizing policy are
//! Rust-owned. C retains ownership of private descriptor fields and platform
//! synchronization.
use std::mem::{self, offset_of, size_of, MaybeUninit};
use std::os::raw::{c_int, c_uint, c_void};
@@ -1055,6 +1056,175 @@ pub type ZSTDMT_initSetBufferSizeFn = unsafe extern "C" fn(*mut c_void, usize);
pub type ZSTDMT_initResizeRoundBufferFn = unsafe extern "C" fn(*mut c_void, usize) -> usize;
pub type ZSTDMT_initResetStreamFn = unsafe extern "C" fn(*mut c_void);
pub type ZSTDMT_initSerialResetFn = unsafe extern "C" fn(*mut c_void, usize) -> usize;
/// Scalar dictionary classification for the MT stream initializer. C keeps
/// dictionary handles, parameter layout, prefix storage, and CDict mutation
/// behind callbacks; Rust owns the copy/borrow/raw-prefix branch selection.
#[repr(C)]
#[derive(Clone, Copy, Debug, Default, PartialEq, Eq)]
pub struct ZSTDMT_RustDictionaryProjection {
pub hasDictionary: c_uint,
pub rawContent: c_uint,
}
const _: () = {
assert!(offset_of!(ZSTDMT_RustDictionaryProjection, hasDictionary) == 0);
assert!(offset_of!(ZSTDMT_RustDictionaryProjection, rawContent) == size_of::<c_uint>());
assert!(size_of::<ZSTDMT_RustDictionaryProjection>() == 2 * size_of::<c_uint>());
};
#[derive(Clone, Copy, Debug, Eq, PartialEq)]
enum PrepareDictionaryAction {
CreateCopied,
AttachBorrowed,
}
#[inline]
fn classify_prepare_dictionary(
projection: ZSTDMT_RustDictionaryProjection,
) -> PrepareDictionaryAction {
if projection.hasDictionary != 0 {
PrepareDictionaryAction::CreateCopied
} else {
PrepareDictionaryAction::AttachBorrowed
}
}
#[derive(Clone, Copy, Debug, Eq, PartialEq)]
enum UpdateDictionaryAction {
AttachBorrowed,
SetRawPrefix,
CreateReferenced,
}
#[inline]
fn classify_update_dictionary(
projection: ZSTDMT_RustDictionaryProjection,
) -> UpdateDictionaryAction {
if projection.hasDictionary == 0 {
UpdateDictionaryAction::AttachBorrowed
} else if projection.rawContent != 0 {
UpdateDictionaryAction::SetRawPrefix
} else {
UpdateDictionaryAction::CreateReferenced
}
}
#[inline]
fn prepare_c_stream_dictionary_with<R, C, A>(
projection: ZSTDMT_RustDictionaryProjection,
mut release_local: R,
mut create_copied: C,
mut attach_borrowed: A,
) -> usize
where
R: FnMut(),
C: FnMut() -> usize,
A: FnMut(),
{
release_local();
match classify_prepare_dictionary(projection) {
PrepareDictionaryAction::CreateCopied => create_copied(),
PrepareDictionaryAction::AttachBorrowed => {
attach_borrowed();
0
}
}
}
#[inline]
fn update_c_stream_dictionary_with<C, A, P, R>(
projection: ZSTDMT_RustDictionaryProjection,
mut clear_local: C,
mut attach_borrowed: A,
mut set_raw_prefix: P,
mut create_referenced: R,
) -> usize
where
C: FnMut(),
A: FnMut(),
P: FnMut(),
R: FnMut() -> usize,
{
clear_local();
match classify_update_dictionary(projection) {
UpdateDictionaryAction::AttachBorrowed => {
attach_borrowed();
0
}
UpdateDictionaryAction::SetRawPrefix => {
set_raw_prefix();
0
}
UpdateDictionaryAction::CreateReferenced => create_referenced(),
}
}
/// Apply the MT stream dictionary transition policy while C retains all
/// private CDict allocation and context publication operations.
#[no_mangle]
pub unsafe extern "C" fn ZSTDMT_rust_prepareCStreamDictionary(
projection: *const ZSTDMT_RustDictionaryProjection,
opaque: *mut c_void,
release_local: Option<ZSTDMT_initResetStreamFn>,
create_copied: Option<ZSTDMT_initDictionaryFn>,
attach_borrowed: Option<ZSTDMT_initResetStreamFn>,
) -> usize {
let Some(projection) = (unsafe { projection.as_ref() }).copied() else {
return ERROR(ZstdErrorCode::Generic);
};
let (Some(release_local), Some(create_copied), Some(attach_borrowed)) =
(release_local, create_copied, attach_borrowed)
else {
return ERROR(ZstdErrorCode::Generic);
};
if opaque.is_null() {
return ERROR(ZstdErrorCode::Generic);
}
prepare_c_stream_dictionary_with(
projection,
|| unsafe { release_local(opaque) },
|| unsafe { create_copied(opaque) },
|| unsafe { attach_borrowed(opaque) },
)
}
/// Apply the MT stream dictionary update policy while C retains private raw
/// prefix and CDict state. The clear step always precedes the selected branch.
#[no_mangle]
pub unsafe extern "C" fn ZSTDMT_rust_updateCStreamDictionary(
projection: *const ZSTDMT_RustDictionaryProjection,
opaque: *mut c_void,
clear_local: Option<ZSTDMT_initResetStreamFn>,
attach_borrowed: Option<ZSTDMT_initResetStreamFn>,
set_raw_prefix: Option<ZSTDMT_initResetStreamFn>,
create_referenced: Option<ZSTDMT_initDictionaryFn>,
) -> usize {
let Some(projection) = (unsafe { projection.as_ref() }).copied() else {
return ERROR(ZstdErrorCode::Generic);
};
let (Some(clear_local), Some(attach_borrowed), Some(set_raw_prefix), Some(create_referenced)) = (
clear_local,
attach_borrowed,
set_raw_prefix,
create_referenced,
) else {
return ERROR(ZstdErrorCode::Generic);
};
if opaque.is_null() {
return ERROR(ZstdErrorCode::Generic);
}
update_c_stream_dictionary_with(
projection,
|| unsafe { clear_local(opaque) },
|| unsafe { attach_borrowed(opaque) },
|| unsafe { set_raw_prefix(opaque) },
|| unsafe { create_referenced(opaque) },
)
}
type ZSTDMT_resetStreamCallbackFn = unsafe extern "C" fn(*mut c_void);
pub type ZSTDMT_serialResetVoidFn = unsafe extern "C" fn(*mut c_void);
pub type ZSTDMT_serialResetSetNbSeqFn = unsafe extern "C" fn(*mut c_void, usize);
@@ -6667,6 +6837,132 @@ mod tests {
}
}
#[test]
fn dictionary_policy_classifies_copy_borrow_and_raw_prefix_branches() {
assert_eq!(
classify_prepare_dictionary(ZSTDMT_RustDictionaryProjection {
hasDictionary: 1,
rawContent: 0,
}),
PrepareDictionaryAction::CreateCopied
);
assert_eq!(
classify_prepare_dictionary(ZSTDMT_RustDictionaryProjection {
hasDictionary: 0,
rawContent: 1,
}),
PrepareDictionaryAction::AttachBorrowed
);
for (projection, expected) in [
(
ZSTDMT_RustDictionaryProjection {
hasDictionary: 0,
rawContent: 0,
},
UpdateDictionaryAction::AttachBorrowed,
),
(
ZSTDMT_RustDictionaryProjection {
hasDictionary: 1,
rawContent: 1,
},
UpdateDictionaryAction::SetRawPrefix,
),
(
ZSTDMT_RustDictionaryProjection {
hasDictionary: 1,
rawContent: 0,
},
UpdateDictionaryAction::CreateReferenced,
),
] {
assert_eq!(classify_update_dictionary(projection), expected);
}
}
#[test]
fn prepare_dictionary_releases_before_copy_or_borrow_action() {
let expected_error = ERROR(ZstdErrorCode::MemoryAllocation);
let events = RefCell::new(Vec::new());
let result = prepare_c_stream_dictionary_with(
ZSTDMT_RustDictionaryProjection {
hasDictionary: 1,
rawContent: 0,
},
|| events.borrow_mut().push("release"),
|| {
events.borrow_mut().push("copy");
expected_error
},
|| panic!("copy branch must not attach borrowed dictionary"),
);
assert_eq!(result, expected_error);
assert_eq!(events.into_inner(), vec!["release", "copy"]);
let events = RefCell::new(Vec::new());
let result = prepare_c_stream_dictionary_with(
ZSTDMT_RustDictionaryProjection {
hasDictionary: 0,
rawContent: 0,
},
|| events.borrow_mut().push("release"),
|| panic!("borrow branch must not create a copied dictionary"),
|| events.borrow_mut().push("borrow"),
);
assert_eq!(result, 0);
assert_eq!(events.into_inner(), vec!["release", "borrow"]);
}
#[test]
fn update_dictionary_clears_before_borrow_raw_or_reference_action() {
let events = RefCell::new(Vec::new());
let result = update_c_stream_dictionary_with(
ZSTDMT_RustDictionaryProjection {
hasDictionary: 0,
rawContent: 0,
},
|| events.borrow_mut().push("clear"),
|| events.borrow_mut().push("borrow"),
|| panic!("borrow branch must not set a raw prefix"),
|| panic!("borrow branch must not create a referenced dictionary"),
);
assert_eq!(result, 0);
assert_eq!(events.into_inner(), vec!["clear", "borrow"]);
let events = RefCell::new(Vec::new());
let result = update_c_stream_dictionary_with(
ZSTDMT_RustDictionaryProjection {
hasDictionary: 1,
rawContent: 1,
},
|| events.borrow_mut().push("clear"),
|| panic!("raw-prefix branch must not attach a borrowed CDict"),
|| events.borrow_mut().push("raw"),
|| panic!("raw-prefix branch must not create a referenced dictionary"),
);
assert_eq!(result, 0);
assert_eq!(events.into_inner(), vec!["clear", "raw"]);
let expected_error = ERROR(ZstdErrorCode::MemoryAllocation);
let events = RefCell::new(Vec::new());
let result = update_c_stream_dictionary_with(
ZSTDMT_RustDictionaryProjection {
hasDictionary: 1,
rawContent: 0,
},
|| events.borrow_mut().push("clear"),
|| panic!("reference branch must not attach a borrowed CDict"),
|| panic!("reference branch must not set a raw prefix"),
|| {
events.borrow_mut().push("reference");
expected_error
},
);
assert_eq!(result, expected_error);
assert_eq!(events.into_inner(), vec!["clear", "reference"]);
}
#[test]
fn init_c_stream_preserves_success_order_and_normalization() {
let projection = init_projection();