Struct TensorDesc 

#[repr(C)]
pub struct TensorDesc {

    pub version: u32,
    pub kind: u32,
    pub handle: i64,
    pub ptr: SendPtr,
    pub ndim: u32,
    pub dtype: u32,
    pub shape: [u64; 8],
    pub strides: [i64; 8],
    pub fourcc: u32,
    pub format: u32,
    pub colorimetry: u32,
    pub flags: u32,
    pub capacity: u64,
    pub sync: u64,
}

The cross-package descriptor. Layout is part of the contract: it is #[repr(C)] and its size is pinned by test.

Fields

version: u32

ABI_VERSION. Checked, never assumed.

kind: u32

One of the kind constants.

handle: i64

dma-buf fd, IOSurface id, GL buffer id or D3D11 texture NT handle value; -1 when unused.

ptr: SendPtr

Host pointer when addressable, else null – except under kind::PBO, where it instead carries a *const crate::pbo::PboOpsVtable, or null if the producer attached none, and under kind::D3D11_TEXTURE, where it carries the process device fence’s NT handle value, or null when Self::sync carries nothing to wait on. Interpretation is keyed by Self::kind, the same established pattern Self::sync’s own doc comment already documents for that field: a PBO tensor never takes a HostPin (PboTensor refuses pin_host — the address cannot outlive the map), so this field is otherwise permanently unused for that kind, which is exactly why it is the field that carries the vtable instead of a new one requiring a layout change. Valid under the exact same borrow contract as the host-pointer case: only while the producer’s own keepalive (for the capsule protocol, the capsule’s) keeps the owning tensor alive.

ndim: u32

Number of significant entries in shape and strides.

dtype: u32

Element type, one of the [dtype] constants.

Deliberately placed here: ndim leaves a 4-byte hole before the 8-aligned shape, so this field costs nothing. Without it strides — documented in elements — cannot be converted to bytes by a consumer, and a Tensor<f32> is indistinguishable from a Tensor<u8> of the same shape.

shape: [u64; 8]

Logical shape, most-significant dimension first.

strides: [i64; 8]

Strides in bytes, signed so a consumer can express flips.

Bytes rather than elements so a hardware row pitch is always representable: a pitch need not be a whole number of dtype elements (and a sub-byte dtype has no element size to divide by). Multiply a coordinate by the stride directly; do not scale by dtype size.

fourcc: u32

DRM FourCC of the pixel format, or 0 for a non-image tensor. Kept for third-party/DRM interop; a HAL-aware consumer should prefer Self::format and fall back to this only when format is 0 (see format’s doc for why fourcc alone is insufficient).

format: u32

One of the format constants, or 0 for a non-image tensor.

colorimetry: u32

Packed colorimetry, or 0 when unspecified.

flags: u32

Bit flags; see flags. Zero when nothing applies.

Occupies what was a 4-byte alignment hole before capacity, so it cost nothing to add.

capacity: u64

Bytes available in the producer’s underlying allocation, from this tensor’s window start (its TensorTrait::capacity_bytes ) – may exceed the byte size shape/strides imply when the producer over-allocated: a pool tensor sized for its largest expected image but holding a smaller one today, or row-pitch/MCU-alignment padding a decoder needs beyond the logical width. Without this, a consumer importing a HOST descriptor has no way to learn that headroom exists and must treat the declared shape as the allocation’s exact size – which starves a later configure_image/set_logical_shape of capacity the producer actually has. DMABUF/IOSURFACE consumers query their real capacity from the handle itself and do not depend on this field, but it is populated for every kind for consistency.

sync: u64

Completion handle for work still in flight against this tensor, or 0 when flags::SYNC_PRESENT is clear.

Filled in by kind::D3D11_TEXTURE producers, and left clear by every other kind in this build. It was declared before any producer set it because the field has to exist before the first release or adding it later costs a capsule-name bump, and it is the one gap the synchronous-at-the-boundary contract cannot close: a foreign producer with queued GPU work has no other way to say “wait on this first”.

Interpretation is keyed by Self::kind, since each backing already implies its own fence flavour and a separate discriminant would be redundant:

• kind::DMABUF – a sync_file fd from DMA_BUF_IOCTL_EXPORT_SYNC_FILE. The consumer owns it and must close it.
• kind::PBO – a GLsync from glFenceSync, valid only in the producer’s share group.
• kind::CUDA_DEVICE – a cudaEvent_t.
• kind::D3D11_TEXTURE – a value on the timeline of the ID3D11Fence Self::ptr names, not a handle of its own: the handle and the value together are what a consumer waits on.
• kind::HOST, kind::IOSURFACE – no fence flavour defined; SYNC_PRESENT must be clear.

Implementations

impl TensorDesc

pub const MAX_NDIM: usize = 8

Maximum rank the fixed-size shape/strides arrays can carry.

pub fn shape(&self) -> &[u64]

The logical shape as a slice.

pub fn strides(&self) -> &[i64]

The strides as a slice, in bytes.

pub fn len(&self) -> u64

Total element count.

pub fn is_empty(&self) -> bool

True when the descriptor addresses no elements.

Trait Implementations

impl Clone for TensorDesc

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for TensorDesc

impl Debug for TensorDesc

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

Formats the value using the given formatter.