Struct DatagramHeader 

pub struct DatagramHeader {
    pub track_alias: VarInt,
    pub group_id: VarInt,
    pub object_id: VarInt,
    pub publisher_priority: u8,
    pub extension_headers_length: VarInt,
    pub extensions: Vec<u8>,
}

Datagram header with payload (draft-10, type 0x01).

Draft-09 dropped these two fields and draft-10 keeps them dropped: no payload_length and no object_status. Payload is the remaining bytes in the datagram.

Encoding (after type varint): track_alias(vi), group_id(vi), object_id(vi), publisher_priority(u8), extension_headers_length(vi), [extensions…], [remaining bytes = payload]

Fields

track_alias: VarInt

Track alias identifying the subscription.

group_id: VarInt

Group identifier.

object_id: VarInt

Object identifier within the group.

publisher_priority: u8

Publisher priority for delivery ordering.

extension_headers_length: VarInt

Total byte length of extension headers, as it arrived.

Advisory on encode. Every encoder here writes VarInt::from_usize(self.extensions.len()) and never reads this field, so a hand-built header whose stated length disagrees with the bytes beside it goes on the wire with the derived length and is read back consistent. Decoding always sets the two together, so a value that came off the wire never disagrees.

It is kept because it is what the peer stated, which is not always recoverable from the bytes: a non-minimal varint length encodes the same number in more bytes, and a relay that must forward the block unchanged has to know which it saw.

extensions: Vec<u8>

Raw extension bytes (opaque).

Implementations

impl DatagramHeader

pub fn encode(&self, buf: &mut impl BufMut)

Encode the datagram header into the buffer.

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

Encode the datagram header, refusing a status the framing cannot carry.

Nothing here is ever refused, and that is a fact about draft-10 rather than a check left out. This is the OBJECT_DATAGRAM of Section 9.2, whose layout carries no Object Status field at all; a datagram that states a status is the separate OBJECT_DATAGRAM_STATUS message of Section 9.3, modelled here as DatagramStatusHeader. So there is no status for Self::encode to drop, and nothing for Section 9.1.1.1’s “Any object with a status code other than zero MUST have an empty payload” to rule on: an object framed this way has status zero by construction.

The fallible signature is what lets one entry point span every draft. dispatch::AnyDatagramHeader::encode calls this on all thirteen, and the drafts whose payload-bearing datagram does carry a status field need somewhere to say no.

pub fn decode(buf: &mut impl Buf) -> Result<Self, CodecError>

Decode a datagram header from the buffer.

Trait Implementations

impl Clone for DatagramHeader

fn clone(&self) -> DatagramHeader

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for DatagramHeader

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

Formats the value using the given formatter.

impl Eq for DatagramHeader

impl PartialEq for DatagramHeader

fn eq(&self, other: &DatagramHeader) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for DatagramHeader