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refactor(compress): move stream result policy to Rust

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Move the post-call ZSTD_compressStream2_c policy into Rust: adapter errors now short-circuit before buffer publication, successful calls publish buffer expectations before calculating pending output, and the private C context remains behind a callback projection. Add ABI assertions and ordering tests for both paths.

Test Plan: git diff --cached --check; focused Rust tests added; full capped Rust/native/original-suite verification will run after the MT slice is integrated.
This commit is contained in:
ddidderr
2026-07-21 07:15:23 +02:00
parent 8ae0dfa49d
commit fc9aeee92b
2 changed files with 220 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files
lib/compress/zstd_compress.c
+66 -3
View File
@@ -774,6 +774,43 @@ size_t ZSTD_compressStream2_c(ZSTD_CCtx* cctx,
ZSTD_outBuffer* output,
ZSTD_inBuffer* input,
ZSTD_EndDirective endOp);
typedef void (*ZSTD_rust_compressStream2SetBufferExpectations_f)(
void* context, const void* output, const void* input);
typedef struct {
void* callbackContext;
ZSTD_rust_compressStream2SetBufferExpectations_f setBufferExpectations;
const void* output;
const void* input;
size_t compressResult;
size_t outBuffContentSize;
size_t outBuffFlushedSize;
} ZSTD_rust_compressStream2ResultPolicyState;
size_t ZSTD_rust_compressStream2ResultPolicy(
const ZSTD_rust_compressStream2ResultPolicyState* state);
typedef char ZSTD_rust_compress_stream2_result_policy_state_layout[
(offsetof(ZSTD_rust_compressStream2ResultPolicyState, callbackContext)
== 0
&& offsetof(ZSTD_rust_compressStream2ResultPolicyState,
setBufferExpectations)
== sizeof(void*)
&& offsetof(ZSTD_rust_compressStream2ResultPolicyState, output)
== 2 * sizeof(void*)
&& offsetof(ZSTD_rust_compressStream2ResultPolicyState, input)
== 3 * sizeof(void*)
&& offsetof(ZSTD_rust_compressStream2ResultPolicyState,
compressResult)
== 4 * sizeof(void*)
&& offsetof(ZSTD_rust_compressStream2ResultPolicyState,
outBuffContentSize)
== 5 * sizeof(void*)
&& offsetof(ZSTD_rust_compressStream2ResultPolicyState,
outBuffFlushedSize)
== 6 * sizeof(void*)
&& sizeof(ZSTD_rust_compressStream2SetBufferExpectations_f)
== sizeof(void*)
&& sizeof(ZSTD_rust_compressStream2ResultPolicyState)
== 7 * sizeof(void*))
? 1 : -1];
typedef struct {
size_t outputPos;
size_t outputSize;
@@ -8005,6 +8042,15 @@ ZSTD_setBufferExpectations(ZSTD_CCtx* cctx, const ZSTD_outBuffer* output, const
input);
}
static void ZSTD_rust_compressStream2_setBufferExpectations(
void* context, const void* output, const void* input)
{
ZSTD_setBufferExpectations(
(ZSTD_CCtx*)context,
(const ZSTD_outBuffer*)output,
(const ZSTD_inBuffer*)input);
}
/* Validate that the input/output buffers match the expectations set by
* ZSTD_setBufferExpectations.
*/
@@ -8529,10 +8575,27 @@ size_t ZSTD_compressStream2_c( ZSTD_CCtx* cctx,
return flushMin;
}
#endif /* ZSTD_MULTITHREAD */
FORWARD_IF_ERROR( ZSTD_compressStream_generic(cctx, output, input, endOp) , "");
{ size_t const compressResult =
ZSTD_compressStream_generic(cctx, output, input, endOp);
if (!ERR_isError(compressResult)) {
DEBUGLOG(5, "completed ZSTD_compressStream2");
ZSTD_setBufferExpectations(cctx, output, input);
return cctx->outBuffContentSize - cctx->outBuffFlushedSize; /* remaining to flush */
}
{ ZSTD_rust_compressStream2ResultPolicyState const state = {
cctx,
ZSTD_rust_compressStream2_setBufferExpectations,
output,
input,
compressResult,
cctx->outBuffContentSize,
cctx->outBuffFlushedSize
};
{ size_t const policyResult =
ZSTD_rust_compressStream2ResultPolicy(&state);
FORWARD_IF_ERROR(policyResult, "");
return policyResult;
}
}
}
}
size_t ZSTD_compressStream2_simpleArgs (
rust/src/zstd_compress.rs
+153
View File
@@ -257,6 +257,96 @@ pub unsafe extern "C" fn ZSTD_rust_compressStream2Policy(
compress_stream2_policy(state.end_op)
}
type CompressStream2SetBufferExpectationsFn =
unsafe extern "C" fn(*mut c_void, *const c_void, *const c_void);
/// Projection for the post-call result policy of `ZSTD_compressStream2_c`.
///
/// C retains the stream adapter and the private buffer-expectation fields.
/// Rust owns the error short-circuit, publication ordering, and pending-output
/// subtraction after the adapter has returned.
#[repr(C)]
pub struct ZSTD_rust_compressStream2ResultPolicyState {
callback_context: *mut c_void,
set_buffer_expectations: Option<CompressStream2SetBufferExpectationsFn>,
output: *const c_void,
input: *const c_void,
compress_result: usize,
out_buff_content_size: usize,
out_buff_flushed_size: usize,
}
const _: () = {
assert!(size_of::<Option<CompressStream2SetBufferExpectationsFn>>() == size_of::<usize>());
assert!(
offset_of!(ZSTD_rust_compressStream2ResultPolicyState, callback_context) == 0
);
assert!(
offset_of!(
ZSTD_rust_compressStream2ResultPolicyState,
set_buffer_expectations
) == size_of::<usize>()
);
assert!(
offset_of!(ZSTD_rust_compressStream2ResultPolicyState, output)
== 2 * size_of::<usize>()
);
assert!(
offset_of!(ZSTD_rust_compressStream2ResultPolicyState, input)
== 3 * size_of::<usize>()
);
assert!(
offset_of!(ZSTD_rust_compressStream2ResultPolicyState, compress_result)
== 4 * size_of::<usize>()
);
assert!(
offset_of!(
ZSTD_rust_compressStream2ResultPolicyState,
out_buff_content_size
) == 5 * size_of::<usize>()
);
assert!(
offset_of!(
ZSTD_rust_compressStream2ResultPolicyState,
out_buff_flushed_size
) == 6 * size_of::<usize>()
);
assert!(
size_of::<ZSTD_rust_compressStream2ResultPolicyState>() == 7 * size_of::<usize>()
);
};
#[inline]
unsafe fn compress_stream2_result_policy(
state: &ZSTD_rust_compressStream2ResultPolicyState,
) -> usize {
if ERR_isError(state.compress_result) {
return state.compress_result;
}
let Some(set_buffer_expectations) = state.set_buffer_expectations else {
return ERROR(ZstdErrorCode::Generic);
};
unsafe {
set_buffer_expectations(state.callback_context, state.output, state.input);
}
state
.out_buff_content_size
.wrapping_sub(state.out_buff_flushed_size)
}
/// Apply the public stream result policy without exposing the private C context
/// layout to Rust.
#[no_mangle]
pub unsafe extern "C" fn ZSTD_rust_compressStream2ResultPolicy(
state: *const ZSTD_rust_compressStream2ResultPolicyState,
) -> usize {
let Some(state) = (unsafe { state.as_ref() }) else {
return ERROR(ZstdErrorCode::Generic);
};
unsafe { compress_stream2_result_policy(state) }
}
/// Projection for the stable-input part of `ZSTD_compressStream2_c`'s
/// transparent initialization stage.
///
@@ -14426,6 +14516,69 @@ mod tests {
assert_eq!(unsafe { ZSTD_rust_compressStream2Policy(ptr::null()) }, 0);
}
#[derive(Default)]
struct CompressStream2ResultPolicyTestContext {
set_buffer_expectations_calls: usize,
}
unsafe extern "C" fn compress_stream2_result_policy_test_set_buffer_expectations(
context: *mut c_void,
output: *const c_void,
input: *const c_void,
) {
assert!(!output.is_null());
assert!(!input.is_null());
let context = unsafe { &mut *context.cast::<CompressStream2ResultPolicyTestContext>() };
context.set_buffer_expectations_calls += 1;
}
#[test]
fn compress_stream2_result_policy_publishes_buffers_before_accounting() {
let mut context = CompressStream2ResultPolicyTestContext::default();
let context_ptr = (&mut context as *mut CompressStream2ResultPolicyTestContext).cast();
let state = ZSTD_rust_compressStream2ResultPolicyState {
callback_context: context_ptr,
set_buffer_expectations: Some(
compress_stream2_result_policy_test_set_buffer_expectations,
),
output: context_ptr,
input: context_ptr,
compress_result: 0,
out_buff_content_size: 17,
out_buff_flushed_size: 5,
};
assert_eq!(
unsafe { ZSTD_rust_compressStream2ResultPolicy(&state) },
12
);
assert_eq!(context.set_buffer_expectations_calls, 1);
}
#[test]
fn compress_stream2_result_policy_returns_adapter_error_without_publishing() {
let mut context = CompressStream2ResultPolicyTestContext::default();
let context_ptr = (&mut context as *mut CompressStream2ResultPolicyTestContext).cast();
let adapter_error = ERROR(ZstdErrorCode::Generic);
let state = ZSTD_rust_compressStream2ResultPolicyState {
callback_context: context_ptr,
set_buffer_expectations: Some(
compress_stream2_result_policy_test_set_buffer_expectations,
),
output: ptr::null(),
input: ptr::null(),
compress_result: adapter_error,
out_buff_content_size: 17,
out_buff_flushed_size: 5,
};
assert_eq!(
unsafe { ZSTD_rust_compressStream2ResultPolicy(&state) },
adapter_error
);
assert_eq!(context.set_buffer_expectations_calls, 0);
}
fn compress_stream2_mt_loop_policy_state(
end_op: c_int,
flush_min: usize,