Struct AnySubgroupObjectWriter 

pub struct AnySubgroupObjectWriter { /* private fields */ }

Serializer for the objects on a subgroup data stream, for any enabled draft.

Mirrors AnySubgroupObjectReader. On drafts 14-19 it tracks the previous Object ID so successive writes produce correct deltas; on drafts 07-13 object IDs are absolute and the same state only enforces that they increase.

Eliding objects

To remove an object from a stream, read it and then simply do not write it. The writer’s delta state advances only when write_object succeeds, so the next object written re-derives its delta against the last retained object automatically. See Self::write_object for the exact invariant.

Implementations

impl AnySubgroupObjectWriter

pub fn new(header: &AnySubgroupHeader) -> Result<Self, CodecError>

Create a writer for a stream with the given header.

The header fixes the extension-presence and (on drafts 11-13) stream type used for every object written, exactly as it does for AnySubgroupObjectReader::new.

pub fn draft(&self) -> DraftVersion

The draft this writer encodes.

pub fn write_object( &mut self, object: &AnySubgroupObject, buf: &mut impl BufMut, ) -> Result<(), CodecError>

Encode one object, advancing the delta state.

Invariant

Let a stream’s objects decode to absolute IDs a_0, a_1, .., a_n. Feeding any strictly-increasing subsequence of those objects through one writer, in order, produces a byte stream that decodes back to exactly that subsequence of absolute IDs, on every draft 07-19.

Concretely: dropping a_2 from 0,1,2,3,4 yields a stream decoding to 0,1,3,4 — not 0,1,2,3.

Errors

CodecError::InvalidField when object.object_id is not strictly greater than the previously written object’s ID (two objects on a subgroup stream can never share an ID, so no valid delta exists), when a computed delta or length exceeds the varint range, when the object carries extension bytes that a stream without an extension block cannot represent, or when a non-empty payload is paired with a status.

Also CodecError::InvalidField when object.status holds a code the draft being written does not assign. AnySubgroupObject::status is a raw wire code because it crosses drafts, and the assigned set moves between them, so a status read off one draft’s stream is not necessarily writable onto another’s: forwarding a draft-15 Object Does Not Exist (0x1) onto a draft-16 or later stream is refused here rather than emitted as a byte the peer must close the session over.

Trait Implementations

impl Clone for AnySubgroupObjectWriter

fn clone(&self) -> AnySubgroupObjectWriter

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for AnySubgroupObjectWriter

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

Formats the value using the given formatter.