Module endpoint 

Draft-20 MoQT endpoint.

Major changes from draft-19:

• FETCH lost its Fetch Type and with it the Standalone and Joining Fetch structures (Section 10.13). Track Namespace and Track Name are inline fields, the range travels in the LOCATION_FILTER parameter, and Endpoint::fetch therefore takes a parameter list where draft-19’s took four location varints. joining_fetch and absolute_joining_fetch are gone, as is INVALID_JOINING_REQUEST_ID (REQUEST_ERROR 0x32) and every rule this endpoint enforced with it.
• Fill fetch streams replace the joining fetch (Sections 5.1.3 and 5.1.3.1). A SUBSCRIBE or REQUEST_UPDATE carrying FILL_PARAMETERS (0x23) asks the publisher for a unidirectional stream that opens with a FETCH_HEADER carrying the subscription’s Request ID. This endpoint records the request in Endpoint::fill_requested so an arriving FETCH_HEADER can be told from a fetch’s, and counts the streams so a PUBLISH_DONE’s Stream Count can include them.
• PUBLISH_STATE_NOTIFY (0x22) is new (Section 10.10): unilateral, from the publisher, on a subscription’s stream, answered with nothing and explicitly outside the MAX_REQUEST_UPDATES ceiling.
• Ranges are inclusive at both ends (Sections 5.1.2, 10.13, 10.14), so no end location in this module carries draft-19’s + 1.
• INCLUDE_PROPERTIES (0x35) is new; SUBSCRIPTION_ENDED (PUBLISH_DONE 0x3) and VERSION_NEGOTIATION_FAILED (session 0x15) are unassigned.
• Six parameters dropped PUBLISH_OK from their scope and several gained PUBLISH; only EXPIRES still names PUBLISH_OK. The table that decides it lives in the codec.

Structs

Endpoint

FetchTrack 🔒

The track one fetch is for, which the fetch’s own state machine does not hold.

FillStreams 🔒

What one subscription’s fill fetch streams amount to, from the point of view of an endpoint that has to attribute an arriving FETCH_HEADER and count the streams a PUBLISH_DONE reports.

TrackBinding 🔒

A Track Alias the peer has attached to a Full Track Name, and the request whose lifetime the attachment follows.

Enums

BindingKind 🔒

Which of the two sequences Section 5.1 names established the subscription that owns a binding, and so which state machine says whether it still has one.

EndpointError

Errors that can occur during endpoint operations.

FilterRejection

Why a peer’s request must be answered with REQUEST_ERROR and INVALID_FILTER.

Constants

MAX_FILTER_RANGES 🔒

The MAX_FILTER_RANGES Setup Option, Section 10.3.1.6.

MAX_REQUEST_UPDATES 🔒

The MAX_REQUEST_UPDATES Setup Option, Section 10.3.1.7.

TRACK_NAMESPACE_PREFIX 🔒

Parameter Type of TRACK_NAMESPACE_PREFIX.

Functions

apply_filter_update 🔒

Apply a REQUEST_UPDATE’s filter parameters to the set already in force.

prefixes_overlap 🔒

Whether two namespace prefixes overlap.

range_filter_parameters 🔒

The Range Filter parameters in parameters, dropping the removals.

request_parameters 🔒

The Message Parameters a request carries, or nothing for a message that is not a request.

setup_varint 🔒

Read a Setup Option’s value as a variable-length integer, or 0 if it is absent.

updated_prefix 🔒

The Track Namespace Prefix a REQUEST_UPDATE asks a namespace subscription to move to, and None when it asks for no such move.