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refactor(compress): move heap CCtx release order to Rust

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ZSTD_freeCCtx previously passed one C callback that bundled dictionary,
multithreaded context, workspace, and heap-object teardown. That left the
lifetime order inside private C control flow and made the public destruction
policy harder to audit. Project the four private operations separately and
let Rust enforce the original dictionary, MT-context, workspace, and
object order while preserving the static-context and workspace-embedded
object guards. The callbacks still own the C layouts and custom allocator
operations.

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
- Broader native and original-test verification remains pending for the complete batch.
This commit is contained in:
ddidderr
2026-07-20 19:41:52 +02:00
parent a152fe6498
commit d714aeac23
2 changed files with 64 additions and 34 deletions
Download Patch File Download Diff File Expand all files Collapse all files
lib/compress/zstd_compress.c
+24 -15
View File
@@ -297,14 +297,15 @@ typedef char ZSTD_rust_ref_thread_pool_state_layout[
&& offsetof(ZSTD_rust_refThreadPoolState, streamStage) == 2 * sizeof(void*)
&& sizeof(ZSTD_rust_refThreadPoolState) == 3 * sizeof(void*))
? 1 : -1];
typedef void (*ZSTD_rust_freeCCtxContent_f)(void* context);
typedef void (*ZSTD_rust_freeCCtxObject_f)(void* context);
typedef void (*ZSTD_rust_freeCCtxCallback_f)(void* context);
typedef struct {
void* callbackContext;
size_t staticSize;
int cctxInWorkspace;
ZSTD_rust_freeCCtxContent_f freeContent;
ZSTD_rust_freeCCtxObject_f freeObject;
ZSTD_rust_freeCCtxCallback_f freeDictionaries;
ZSTD_rust_freeCCtxCallback_f freeMTContext;
ZSTD_rust_freeCCtxCallback_f freeWorkspace;
ZSTD_rust_freeCCtxCallback_f freeObject;
} ZSTD_rust_freeCCtxState;
size_t ZSTD_rust_freeCCtx(const ZSTD_rust_freeCCtxState* state);
typedef char ZSTD_rust_free_cctx_state_layout[
@@ -312,11 +313,15 @@ typedef char ZSTD_rust_free_cctx_state_layout[
&& offsetof(ZSTD_rust_freeCCtxState, staticSize) == sizeof(void*)
&& offsetof(ZSTD_rust_freeCCtxState, cctxInWorkspace)
== 2 * sizeof(void*)
&& offsetof(ZSTD_rust_freeCCtxState, freeContent)
&& offsetof(ZSTD_rust_freeCCtxState, freeDictionaries)
== 3 * sizeof(void*)
&& offsetof(ZSTD_rust_freeCCtxState, freeObject)
&& offsetof(ZSTD_rust_freeCCtxState, freeMTContext)
== 4 * sizeof(void*)
&& sizeof(ZSTD_rust_freeCCtxState) == 5 * sizeof(void*))
&& offsetof(ZSTD_rust_freeCCtxState, freeWorkspace)
== 5 * sizeof(void*)
&& offsetof(ZSTD_rust_freeCCtxState, freeObject)
== 6 * sizeof(void*)
&& sizeof(ZSTD_rust_freeCCtxState) == 7 * sizeof(void*))
? 1 : -1];
typedef int (*ZSTD_rust_createCCtxValidateCustomMem_f)(void* context);
typedef void* (*ZSTD_rust_createCCtxAllocate_f)(void* context, size_t size);
@@ -3635,20 +3640,20 @@ static size_t ZSTD_sizeof_localDict(ZSTD_localDict dict)
cdictSize);
}
static void ZSTD_freeCCtxContent(ZSTD_CCtx* cctx)
static void ZSTD_rust_freeCCtx_freeMTContext(void* context)
{
assert(cctx != NULL);
assert(cctx->staticSize == 0);
ZSTD_clearAllDicts(cctx);
#ifdef ZSTD_MULTITHREAD
ZSTD_CCtx* const cctx = (ZSTD_CCtx*)context;
ZSTDMT_freeCCtx(cctx->mtctx); cctx->mtctx = NULL;
#else
(void)context;
#endif
ZSTD_cwksp_free(&cctx->workspace, cctx->customMem);
}
static void ZSTD_rust_freeCCtx_freeContent(void* context)
static void ZSTD_rust_freeCCtx_freeWorkspace(void* context)
{
ZSTD_freeCCtxContent((ZSTD_CCtx*)context);
ZSTD_CCtx* const cctx = (ZSTD_CCtx*)context;
ZSTD_cwksp_free(&cctx->workspace, cctx->customMem);
}
static void ZSTD_rust_freeCCtx_freeObject(void* context)
@@ -3666,7 +3671,11 @@ size_t ZSTD_freeCCtx(ZSTD_CCtx* cctx)
state.cctxInWorkspace = cctx != NULL && cctx->staticSize == 0
? ZSTD_cwksp_owns_buffer(&cctx->workspace, cctx)
: 0;
state.freeContent = ZSTD_rust_freeCCtx_freeContent;
/* Rust owns the release order; these callbacks retain only private C
* dictionary, MT-context, workspace, and object operations. */
state.freeDictionaries = ZSTD_clearAllDicts_callback;
state.freeMTContext = ZSTD_rust_freeCCtx_freeMTContext;
state.freeWorkspace = ZSTD_rust_freeCCtx_freeWorkspace;
state.freeObject = ZSTD_rust_freeCCtx_freeObject;
return ZSTD_rust_freeCCtx(&state);
}
rust/src/zstd_compress.rs
+40 -19
View File
@@ -2550,34 +2550,38 @@ pub unsafe extern "C" fn ZSTD_rust_initStaticCCtx(
}
}
type FreeCCtxContentFn = unsafe extern "C" fn(*mut c_void);
type FreeCCtxObjectFn = unsafe extern "C" fn(*mut c_void);
type FreeCCtxCallbackFn = unsafe extern "C" fn(*mut c_void);
/// Explicit projection for the public `ZSTD_freeCCtx` wrapper.
///
/// Rust owns the null/static/embedded-object policy and callback ordering.
/// C retains the private content teardown and custom allocator callbacks.
/// Rust owns the null/static/embedded-object policy and the release order.
/// C retains only the private dictionary, MT-context, workspace, and custom
/// allocator operations behind narrow callbacks.
#[repr(C)]
pub struct ZSTD_rust_freeCCtxState {
callback_context: *mut c_void,
static_size: usize,
cctx_in_workspace: c_int,
free_content: FreeCCtxContentFn,
free_object: FreeCCtxObjectFn,
free_dictionaries: FreeCCtxCallbackFn,
free_mt_context: FreeCCtxCallbackFn,
free_workspace: FreeCCtxCallbackFn,
free_object: FreeCCtxCallbackFn,
}
const _: () = {
assert!(size_of::<FreeCCtxContentFn>() == size_of::<usize>());
assert!(size_of::<FreeCCtxObjectFn>() == size_of::<usize>());
assert!(size_of::<FreeCCtxCallbackFn>() == size_of::<usize>());
assert!(offset_of!(ZSTD_rust_freeCCtxState, callback_context) == 0);
assert!(offset_of!(ZSTD_rust_freeCCtxState, static_size) == size_of::<usize>());
assert!(offset_of!(ZSTD_rust_freeCCtxState, cctx_in_workspace) == 2 * size_of::<usize>());
assert!(offset_of!(ZSTD_rust_freeCCtxState, free_content) == 3 * size_of::<usize>());
assert!(offset_of!(ZSTD_rust_freeCCtxState, free_object) == 4 * size_of::<usize>());
assert!(size_of::<ZSTD_rust_freeCCtxState>() == 5 * size_of::<usize>());
assert!(offset_of!(ZSTD_rust_freeCCtxState, free_dictionaries) == 3 * size_of::<usize>());
assert!(offset_of!(ZSTD_rust_freeCCtxState, free_mt_context) == 4 * size_of::<usize>());
assert!(offset_of!(ZSTD_rust_freeCCtxState, free_workspace) == 5 * size_of::<usize>());
assert!(offset_of!(ZSTD_rust_freeCCtxState, free_object) == 6 * size_of::<usize>());
assert!(size_of::<ZSTD_rust_freeCCtxState>() == 7 * size_of::<usize>());
};
/// Free the C-owned context content and, when applicable, its outer object.
/// Release a heap CCtx in the original dictionary, MT-context, workspace, and
/// outer-object order.
#[no_mangle]
pub unsafe extern "C" fn ZSTD_rust_freeCCtx(state: *const ZSTD_rust_freeCCtxState) -> usize {
if state.is_null() {
@@ -2591,7 +2595,9 @@ pub unsafe extern "C" fn ZSTD_rust_freeCCtx(state: *const ZSTD_rust_freeCCtxStat
return ERROR(ZstdErrorCode::MemoryAllocation);
}
unsafe {
(state.free_content)(state.callback_context);
(state.free_dictionaries)(state.callback_context);
(state.free_mt_context)(state.callback_context);
(state.free_workspace)(state.callback_context);
if state.cctx_in_workspace == 0 {
(state.free_object)(state.callback_context);
}
@@ -19025,9 +19031,19 @@ mod tests {
events: Vec<&'static str>,
}
unsafe extern "C" fn free_cctx_test_content(context: *mut c_void) {
unsafe extern "C" fn free_cctx_test_dictionaries(context: *mut c_void) {
let context = unsafe { &mut *context.cast::<FreeCCtxTestContext>() };
context.events.push("content");
context.events.push("dictionaries");
}
unsafe extern "C" fn free_cctx_test_mt_context(context: *mut c_void) {
let context = unsafe { &mut *context.cast::<FreeCCtxTestContext>() };
context.events.push("mt-context");
}
unsafe extern "C" fn free_cctx_test_workspace(context: *mut c_void) {
let context = unsafe { &mut *context.cast::<FreeCCtxTestContext>() };
context.events.push("workspace");
}
unsafe extern "C" fn free_cctx_test_object(context: *mut c_void) {
@@ -19044,20 +19060,25 @@ mod tests {
callback_context: context,
static_size,
cctx_in_workspace,
free_content: free_cctx_test_content,
free_dictionaries: free_cctx_test_dictionaries,
free_mt_context: free_cctx_test_mt_context,
free_workspace: free_cctx_test_workspace,
free_object: free_cctx_test_object,
}
}
#[test]
fn free_cctx_frees_content_before_an_external_object() {
fn free_cctx_releases_dictionaries_mt_context_and_workspace_before_object() {
let mut context = FreeCCtxTestContext::default();
let state = free_cctx_test_state((&mut context as *mut FreeCCtxTestContext).cast(), 0, 0);
let result = unsafe { ZSTD_rust_freeCCtx(&state) };
assert_eq!(result, 0);
assert_eq!(context.events, ["content", "object"]);
assert_eq!(
context.events,
["dictionaries", "mt-context", "workspace", "object"]
);
}
#[test]
@@ -19068,7 +19089,7 @@ mod tests {
let result = unsafe { ZSTD_rust_freeCCtx(&state) };
assert_eq!(result, 0);
assert_eq!(context.events, ["content"]);
assert_eq!(context.events, ["dictionaries", "mt-context", "workspace"]);
}
#[test]