Enum Datagram 

pub enum Datagram {
    Payload(DatagramHeader),
    Status(DatagramStatusHeader),
}

One datagram, of whichever shape its type field names.

A MoQT datagram opens with a variable-length integer naming its type, and that integer is what says which of the layouts above follows it, and whether an extension block sits inside it. Neither DatagramHeader nor DatagramStatusHeader reads or writes it, so neither can be handed the first byte of a datagram a peer sent, and neither produces bytes a peer can read. This is the entry point that does both.

The payload of a payload-bearing datagram runs to the end of the QUIC datagram, so it is not part of this value: Self::decode stops at the end of the header and leaves the payload in the buffer, and a caller appends the payload after Self::encode.

Variants

Payload(DatagramHeader)

An object carrying a payload.

Status(DatagramStatusHeader)

An object stating a status, with no payload.

Implementations

impl Datagram

pub fn is_status(&self) -> bool

Whether this datagram states an Object Status instead of carrying a payload.

pub fn datagram_type(&self) -> DatagramType

The type field this value writes.

The extensions bit is taken from the extension bytes themselves rather than from the declared length beside them, which is what keeps the type and the body from contradicting each other: a datagram whose type announces extensions and then declares a length of 0 closes the session on receipt, and one that announces none has nowhere to put them. The end of group bit has no home in the body at all, so it comes from the header flag and goes nowhere else.

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

Decode a datagram from its first byte, type field included.

Errors with CodecError::UnknownDatagramType when the datagram table does not assign the leading type, which this draft answers with a close. datagram_type_error settles it against that table alone — 0x05 is assigned in both tables here and means different things in each.

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

Encode the datagram, type field included.

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

Encode the datagram, refusing a header the framing it names cannot carry.

The body is built before anything reaches buf, so a refused datagram leaves buf untouched rather than a type field with no body under it.

Trait Implementations

impl Clone for Datagram

fn clone(&self) -> Datagram

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Datagram

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

Formats the value using the given formatter.

impl Eq for Datagram

impl PartialEq for Datagram

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for Datagram