feat(compress): move end-of-frame orchestration into Rust

Move ZSTD_compressEnd_public's continuation, epilogue placement, pledged-size validation, trace ordering, and output accounting into the Rust compression projection. Keep CCtx-dependent continuation, checksum/epilogue, and trace behavior behind opaque C callbacks with compile-time ABI layout checks. Test Plan: - ulimit -v 41943040; CARGO_BUILD_JOBS=1 cargo test --manifest-path rust/Cargo.toml compress_end_ -- --test-threads=1 - ulimit -v 41943040; make -B -C lib -j1 lib - ulimit -v 41943040; make -B -C programs -j1 zstd - ulimit -v 41943040; make -B -C tests -j1 test-cli-tests
2026-07-19 10:52:09 +02:00
parent 3b2e8155cd
commit bd7fbc81fc
2 changed files with 342 additions and 21 deletions
@@ -586,6 +586,114 @@ pub unsafe extern "C" fn ZSTD_rust_compressContinue(
    }
 }

+type CompressEndContinueFn = unsafe extern "C" fn(
+    *mut c_void,
+    *mut c_void,
+    usize,
+    *const c_void,
+    usize,
+    c_uint,
+    c_uint,
+) -> usize;
+type CompressEndEpilogueFn = unsafe extern "C" fn(*mut c_void, *mut c_void, usize) -> usize;
+type CompressEndTraceFn = unsafe extern "C" fn(*mut c_void, usize);
+
+/// Explicit projection for the public end-of-frame orchestration.
+///
+/// Rust owns callback ordering, output offset/capacity accounting, and
+/// pledged-size validation.  The opaque callback context retains the private
+/// CCtx-dependent continue, epilogue, checksum, and trace operations in C.
+#[repr(C)]
+pub struct ZSTD_rust_compressEndState {
+    callback_context: *mut c_void,
+    compress_continue: CompressEndContinueFn,
+    write_epilogue: CompressEndEpilogueFn,
+    trace: CompressEndTraceFn,
+    consumed_src_size: *const u64,
+    pledged_src_size_plus_one: u64,
+    content_size_flag: c_int,
+}
+
+const _: () = {
+    assert!(offset_of!(ZSTD_rust_compressEndState, callback_context) == 0);
+    assert!(offset_of!(ZSTD_rust_compressEndState, compress_continue) == size_of::<usize>());
+    assert!(offset_of!(ZSTD_rust_compressEndState, write_epilogue) == 2 * size_of::<usize>());
+    assert!(offset_of!(ZSTD_rust_compressEndState, trace) == 3 * size_of::<usize>());
+    assert!(offset_of!(ZSTD_rust_compressEndState, consumed_src_size) == 4 * size_of::<usize>());
+    assert!(
+        offset_of!(ZSTD_rust_compressEndState, pledged_src_size_plus_one) == 5 * size_of::<usize>()
+    );
+    assert!(
+        offset_of!(ZSTD_rust_compressEndState, content_size_flag)
+            == 5 * size_of::<usize>() + size_of::<u64>()
+    );
+    assert!(
+        size_of::<ZSTD_rust_compressEndState>() == if size_of::<usize>() == 8 { 56 } else { 32 }
+    );
+};
+
+unsafe fn compress_end_body_with(
+    state: &ZSTD_rust_compressEndState,
+    dst: *mut c_void,
+    dst_capacity: usize,
+    src: *const c_void,
+    src_size: usize,
+) -> usize {
+    if state.consumed_src_size.is_null() {
+        return ERROR(ZstdErrorCode::Generic);
+    }
+
+    let c_size = unsafe {
+        (state.compress_continue)(
+            state.callback_context,
+            dst,
+            dst_capacity,
+            src,
+            src_size,
+            1,
+            1,
+        )
+    };
+    if ERR_isError(c_size) {
+        return c_size;
+    }
+
+    let end_result = unsafe {
+        (state.write_epilogue)(
+            state.callback_context,
+            dst.cast::<u8>().add(c_size).cast(),
+            dst_capacity.wrapping_sub(c_size),
+        )
+    };
+    if ERR_isError(end_result) {
+        return end_result;
+    }
+
+    debug_assert!(!(state.content_size_flag != 0 && state.pledged_src_size_plus_one == 0));
+    if state.pledged_src_size_plus_one != 0
+        && state.pledged_src_size_plus_one != unsafe { (*state.consumed_src_size).wrapping_add(1) }
+    {
+        return ERROR(ZstdErrorCode::SrcSizeWrong);
+    }
+
+    unsafe { (state.trace)(state.callback_context, end_result) };
+    c_size.wrapping_add(end_result)
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn ZSTD_rust_compressEnd(
+    state: *const ZSTD_rust_compressEndState,
+    dst: *mut c_void,
+    dst_capacity: usize,
+    src: *const c_void,
+    src_size: usize,
+) -> usize {
+    if state.is_null() {
+        return ERROR(ZstdErrorCode::Generic);
+    }
+    unsafe { compress_end_body_with(&*state, dst, dst_capacity, src, src_size) }
+}
+
 type Compress2ResetFn = unsafe extern "C" fn(*mut c_void) -> usize;
 type Compress2SetBufferModesFn = unsafe extern "C" fn(*mut c_void, c_int, c_int);
 type Compress2StreamEndFn = unsafe extern "C" fn(
@@ -5141,6 +5249,164 @@ mod tests {
        assert_eq!((context.in_buffer_mode, context.out_buffer_mode), (7, 8));
    }

+    #[derive(Default)]
+    struct CompressEndTestContext {
+        events: Vec<&'static str>,
+        continue_result: usize,
+        epilogue_result: usize,
+        epilogue_offset: usize,
+        epilogue_capacity: usize,
+        trace_extra: usize,
+        continue_frame: c_uint,
+        continue_last_frame_chunk: c_uint,
+        dst_base: usize,
+    }
+
+    unsafe fn compress_end_test_context(
+        context: *mut c_void,
+    ) -> &'static mut CompressEndTestContext {
+        unsafe { &mut *context.cast::<CompressEndTestContext>() }
+    }
+
+    unsafe extern "C" fn compress_end_test_continue(
+        context: *mut c_void,
+        _dst: *mut c_void,
+        _dst_capacity: usize,
+        _src: *const c_void,
+        _src_size: usize,
+        frame: c_uint,
+        last_frame_chunk: c_uint,
+    ) -> usize {
+        let context = unsafe { compress_end_test_context(context) };
+        context.events.push("continue");
+        context.continue_frame = frame;
+        context.continue_last_frame_chunk = last_frame_chunk;
+        context.continue_result
+    }
+
+    unsafe extern "C" fn compress_end_test_epilogue(
+        context: *mut c_void,
+        dst: *mut c_void,
+        dst_capacity: usize,
+    ) -> usize {
+        let context = unsafe { compress_end_test_context(context) };
+        context.events.push("epilogue");
+        context.epilogue_offset = (dst as usize).wrapping_sub(context.dst_base);
+        context.epilogue_capacity = dst_capacity;
+        context.epilogue_result
+    }
+
+    unsafe extern "C" fn compress_end_test_trace(context: *mut c_void, extra_c_size: usize) {
+        let context = unsafe { compress_end_test_context(context) };
+        context.events.push("trace");
+        context.trace_extra = extra_c_size;
+    }
+
+    fn compress_end_test_state(
+        context: &mut CompressEndTestContext,
+        consumed_src_size: &u64,
+        pledged_src_size_plus_one: u64,
+        content_size_flag: c_int,
+    ) -> ZSTD_rust_compressEndState {
+        ZSTD_rust_compressEndState {
+            callback_context: (context as *mut CompressEndTestContext).cast(),
+            compress_continue: compress_end_test_continue,
+            write_epilogue: compress_end_test_epilogue,
+            trace: compress_end_test_trace,
+            consumed_src_size: consumed_src_size as *const u64,
+            pledged_src_size_plus_one,
+            content_size_flag,
+        }
+    }
+
+    #[test]
+    fn compress_end_preserves_callback_order_and_output_accounting() {
+        let mut dst = [0u8; 16];
+        let mut context = CompressEndTestContext {
+            continue_result: 3,
+            epilogue_result: 5,
+            dst_base: dst.as_mut_ptr() as usize,
+            ..CompressEndTestContext::default()
+        };
+        let consumed_src_size = 7;
+        let state = compress_end_test_state(&mut context, &consumed_src_size, 8, 1);
+
+        let result = unsafe {
+            ZSTD_rust_compressEnd(&state, dst.as_mut_ptr().cast(), dst.len(), ptr::null(), 0)
+        };
+
+        assert_eq!(result, 8);
+        assert_eq!(context.events, ["continue", "epilogue", "trace"]);
+        assert_eq!(
+            (context.continue_frame, context.continue_last_frame_chunk),
+            (1, 1)
+        );
+        assert_eq!(
+            (context.epilogue_offset, context.epilogue_capacity),
+            (3, 13)
+        );
+        assert_eq!(context.trace_extra, 5);
+    }
+
+    #[test]
+    fn compress_end_stops_before_epilogue_when_continue_fails() {
+        let mut dst = [0u8; 16];
+        let mut context = CompressEndTestContext {
+            continue_result: ERROR(ZstdErrorCode::MemoryAllocation),
+            dst_base: dst.as_mut_ptr() as usize,
+            ..CompressEndTestContext::default()
+        };
+        let consumed_src_size = 7;
+        let state = compress_end_test_state(&mut context, &consumed_src_size, 8, 0);
+
+        let result = unsafe {
+            ZSTD_rust_compressEnd(&state, dst.as_mut_ptr().cast(), dst.len(), ptr::null(), 0)
+        };
+
+        assert_eq!(result, ERROR(ZstdErrorCode::MemoryAllocation));
+        assert_eq!(context.events, ["continue"]);
+    }
+
+    #[test]
+    fn compress_end_stops_before_validation_and_trace_when_epilogue_fails() {
+        let mut dst = [0u8; 16];
+        let mut context = CompressEndTestContext {
+            continue_result: 3,
+            epilogue_result: ERROR(ZstdErrorCode::MemoryAllocation),
+            dst_base: dst.as_mut_ptr() as usize,
+            ..CompressEndTestContext::default()
+        };
+        let consumed_src_size = 7;
+        let state = compress_end_test_state(&mut context, &consumed_src_size, 99, 1);
+
+        let result = unsafe {
+            ZSTD_rust_compressEnd(&state, dst.as_mut_ptr().cast(), dst.len(), ptr::null(), 0)
+        };
+
+        assert_eq!(result, ERROR(ZstdErrorCode::MemoryAllocation));
+        assert_eq!(context.events, ["continue", "epilogue"]);
+    }
+
+    #[test]
+    fn compress_end_rejects_pledged_size_before_trace() {
+        let mut dst = [0u8; 16];
+        let mut context = CompressEndTestContext {
+            continue_result: 3,
+            epilogue_result: 5,
+            dst_base: dst.as_mut_ptr() as usize,
+            ..CompressEndTestContext::default()
+        };
+        let consumed_src_size = 7;
+        let state = compress_end_test_state(&mut context, &consumed_src_size, 99, 1);
+
+        let result = unsafe {
+            ZSTD_rust_compressEnd(&state, dst.as_mut_ptr().cast(), dst.len(), ptr::null(), 0)
+        };
+
+        assert_eq!(result, ERROR(ZstdErrorCode::SrcSizeWrong));
+        assert_eq!(context.events, ["continue", "epilogue"]);
+    }
+
    #[derive(Default)]
    struct CompressStreamInitTestContext {
        events: Vec<&'static str>,