Struct SubgroupHeader

Source

pub struct SubgroupHeader {
    pub stream_type: StreamType,
    pub track_alias: VarInt,
    pub group_id: VarInt,
    pub subgroup_id: VarInt,
    pub publisher_priority: u8,
}

Fields§

§stream_type: StreamType§track_alias: VarInt§group_id: VarInt§subgroup_id: VarInt§publisher_priority: u8

Implementations§

Source §

impl SubgroupHeader

Source

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

Encode a subgroup stream header including its leading stream-type field, so the bytes form the start of a data stream a peer can read.

Self::encode writes the body alone, which is what a caller wants once the stream is already open and what a caller must not use for its first write. It is also the half that cannot stand on its own here, because the stream type is what says whether a Subgroup ID follows it and whether the objects on the stream carry extension headers.

Source

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

Encode the header body, without its leading stream-type field.

Driven by the stream type, and silent about a subgroup_id it decides not to write: on a type whose Subgroup ID Field Present column reads No the field is dropped, and the peer reads the subgroup the type names - zero, or the first Object’s ID - rather than the one in hand. Nothing is malformed about the result, which is what makes it worth refusing rather than tolerating. Self::encode_checked refuses it.

Source

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

Encode the header body, refusing a Subgroup ID this stream type has nowhere to put.

Self::decode_with_type leaves the field at zero for every type that does not carry it, so a decoded header always passes: the refusal is for a header assembled by hand, where a caller set an ID the type will discard.

A zero is accepted under any type. It is what the decoder produces, and on a Subgroup ID Value column reading 0 it is also the truth, so refusing it would refuse the ordinary case to catch nothing.

§Errors

CodecError::InvalidField if a non-zero Subgroup ID sits under a stream type that writes no Subgroup ID field.

Source

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

Source

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

Source

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

Decode a subgroup header from the start of a data stream, consuming the leading stream type varint and using it to select the variant.

Errors with CodecError::UnknownStreamType when the stream table does not assign the leading type, which this draft answers with a close, and with CodecError::InvalidField when it does assign it but not to a subgroup. stream_type_error draws that line.