wired_moqtrun_fetch Struct Reference

One FETCH response being served from the hub cache: Objects of the track incarnation cache_tag in [cursor, end) go out on one uni stream (FETCH_HEADER, then fetch Objects, 11.4.4), one item per stream round as the transport accepts them. More...

#include <moqtrun.h>

Data Fields
wired_wt_session *	wt
	The requesting session (owned by the transport).
u64	request_id
	The FETCH's Request ID (a fill: its subscription's).
u64	cache_tag
	The track incarnation served (wired_moqtrun_track.cache_tag).
moqctl_loc	cursor
	Next Location to serve.
moqctl_loc	end
	First Location past the range.
u64	stream_id
	The hub-opened uni stream the response goes out on.
moqfetch_seq	seq
	Fetch-Object encoding state carried between items (11.4.4).
u64	owner_rid
	Fill only: the owning subscription's Request ID – with wt it is the owner key.
moqctl_loc	lo
	Descending only: the first Location of the whole range.
u64	last_ok_ms
	Clock (wired_moqt_tick) of the last accepted round: a fetch refused for longer than WIRED_MOQTREL_STALL_MS is given up.
wired_wt_session *	up_wt
	The upstream session the FETCH went to.
u64	up_req_sid
	The hub-opened request stream carrying the upstream FETCH.
u64	up_rid
	The upstream FETCH's Request ID (its FETCH_HEADER names it).
u64	up_data_sid
	The upstream fetch data stream.
moqfetch_seq	up_seq
	Fetch-Object decoding state of the upstream data stream.
moqctl_loc	up_lo
	Upstream Locations must lie in [up_lo, up_span_end): the range start and, ascending, the first Location the cache vouches for again (descending: the range end).
moqctl_loc	up_span_end
	See up_lo.
moqctl_loc	up_last
	The last relayed item's Location; valid iff has_up_last.
u64	up_pl_left
	Payload bytes of the Object at up_last still to pass through as they arrive (its head and the bytes before went out already).
u64	up_pl_at
	Payload bytes of that Object passed through so far.
moqctl_loc	up_end
	The upstream FETCH_OK End Location, inclusive; valid iff up_state is WIRED_MOQTRUN_UPF_OK.
u64	up_deadline_ms
	Clock past which the upstream FETCH is cancelled.
u64	up_budget_ms
	The leg's budget: min(FILL_TIMEOUT, WIRED_MOQTRUN_UPFETCH_BUDGET_MS).
u64	req_sid
	no_track: the downstream request stream the answer goes on.
int	in_use
	1 while the slot serves (or, in fetch_waits, holds) a fetch.
int	opened
	1 once the stream is open (stream_id valid).
int	is_fill
	1 when this fetch is a fill of a subscription (draft-22 SS9.20.15): it was opened by the hub, not requested by a FETCH.
int	failed
	Fill only: 1 once the upstream publisher left.
int	descending
	1 when Group Order is Descending (11.4.4.1): [cursor, end) is then one group's window, stepped down a group at a time until lo's.
int	up_state
	WIRED_MOQTRUN_UPF_*: the upstream FETCH filling the front of the range.
int	up_data_open
	1 once the upstream data stream up_data_sid is bound to this slot; it stays bound (later bytes are discarded) after the leg ends.
int	up_data_end
	1 once the upstream data stream ended (FIN or reset).
int	has_up_last
	1 once an upstream item was relayed.
int	up_eot
	The upstream FETCH_OK End Of Track.
int	up_tmo
	1 when the cache side reports what it lacks as timed out: the budget ran out, or FILL_TIMEOUT was 0.
int	no_track
	1 for a FETCH of a track the hub does not hold: its FETCH_OK waits for the upstream one.
int	answered
	no_track: 1 once the downstream FETCH was answered.

Detailed Description

One FETCH response being served from the hub cache: Objects of the track incarnation cache_tag in [cursor, end) go out on one uni stream (FETCH_HEADER, then fetch Objects, 11.4.4), one item per stream round as the transport accepts them.

The cursor is a Location, never a pointer into the cache: an item is looked up again on every round, so eviction or a publisher leaving in between turns it into an End of Unknown Range instead of reading freed bytes.

Field Documentation

failed

int wired_moqtrun_fetch::failed

Fill only: 1 once the upstream publisher left.

An open fill was reset at once; a held one opens later only to reset (failure is signalled by open-then-reset, draft-22 3.3.4).

owner_rid

u64 wired_moqtrun_fetch::owner_rid

Fill only: the owning subscription's Request ID – with wt it is the owner key.

A fill outlives its subscription's PUBLISH_DONE until its own FIN, so no pointer or index into a reusable subscription slot is ever held.

up_state

int wired_moqtrun_fetch::up_state

WIRED_MOQTRUN_UPF_*: the upstream FETCH filling the front of the range.

While it is in flight the cache side neither serves nor stall-checks; [cursor, end) waits untouched for it to end.

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The documentation for this struct was generated from the following file:

• app/moqt/run/moqtrun.h