Struct CdynBox 

#[repr(C)]
pub struct CdynBox {
    pub data: *mut c_void,
    pub len: usize,
    pub free: unsafe extern "C" fn(data: *mut c_void, len: usize),
}

A cross-module data box: memory allocated and freed by the same module.

This is the cdyn mode’s raw-data smart pointer, complementing the ref-counted instance handle CdynHandle<T>:

• Instance objects (with vtables) → ref-counted, use AbiStableDynRef’s retain/release via CdynHandle<T>.
• Raw data buffers (payloads, serialized blobs, arrays) → single-owner, use this struct’s free function pointer.

Both share the same principle: the deallocator lives in the module that allocated the memory, so allocator mismatches across module/CRT boundaries (notably on Windows) can never corrupt the heap.

The box is move-only: there is exactly one owner, and dropping it (or explicitly calling free) hands the memory back to its origin module. Ref-counted sharing of data should be modeled as an instance instead.

C/C++/Zig side

Any language can produce a box: allocate, fill, and export struct { void* data; size_t len; void (*free)(void*, size_t); } where free calls the module’s own allocator (C++: operator delete[] / std::free, Zig: allocator.free). The layout is #[repr(C)] / plain C struct.

Fields

data: *mut c_void

Pointer to the data. Allocated by the producing module.

len: usize

Length in bytes.

free: unsafe extern "C" fn(data: *mut c_void, len: usize)

Frees data. Must be a function from the module that allocated it.

Implementations

impl CdynBox

pub const fn null() -> Self

A null box (no data, free is a no-op).

pub fn is_null(&self) -> bool

pub fn from_vec(v: Vec<u8>) -> Self

Plugin side (Rust) — wrap an owned Vec<u8> into a box.

The buffer is exact-fit (into_boxed_slice), so len == capacity and the paired cdyn_box_free_rust can reconstruct and free it. The returned free pointer executes in the plugin’s code — the module that owns the allocation.

pub unsafe fn as_slice(&self) -> &[u8]

View the contents as a byte slice.

Safety

data must point to len readable bytes for the lifetime of &self.

pub fn into_raw(self) -> (Self, bool)

Hand ownership back to the caller (no free on drop afterwards).

Trait Implementations

impl Clone for CdynBox

fn clone(&self) -> CdynBox

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for CdynBox

impl Debug for CdynBox

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Send for CdynBox

impl Sync for CdynBox