Struct PrerollContext 

pub struct PrerollContext { /* private fields */ }

Shared completion state for one preroll pass.

Implementations

impl PrerollContext

pub fn new(terminals: impl IntoIterator<Item = ElementId>) -> Self

Creates a preroll that completes once every supplied terminal ID is marked ready (or EOS-equivalent).

pub fn for_seek( terminals: impl IntoIterator<Item = ElementId>, target: Duration, ) -> Self

Creates a seek preroll whose decoded timing gates should discard samples before target while decoding forward from the landed keyframe.

pub fn target(&self) -> Option<Duration>

Exact requested position for seek preroll, or None for ordinary first-sample preroll.

pub fn mark_ready(&self, terminal: ElementId)

Marks one expected terminal’s first valid sample as ready.

pub fn mark_eos(&self, terminal: ElementId)

EOS means this terminal cannot produce a sample and therefore must not leave the whole preroll waiting forever.

pub fn mark_departed(&self, terminal: ElementId)

Stops expecting a terminal that has left the graph.

The expected set is fixed when the seek starts, but the topology is not: detaching a Tee branch mid-seek removes its terminal without removing the obligation to hear from it, and the wait would run to its timeout for a sample nobody is left to produce. Like EOS, this is “cannot produce one”, not “produced one”.

pub fn is_ready(&self, terminal: ElementId) -> bool

Whether this one terminal has already taken its preroll sample.

A terminal stops accepting as soon as it is ready, not when the whole preroll is. Waiting for the others would let a branch that reached the target first keep consuming for as long as the slowest branch takes — which is how the two streams end up at different positions when preroll finally completes.

pub fn is_complete(&self) -> bool

Returns whether every expected terminal has completed this preroll.

pub fn cancel(&self)

Cancels a pending wait, used by stop and failed seek recovery.

pub fn wait(&self, timeout: Duration) -> Result<(), PrerollError>

Waits until every expected terminal is ready, cancellation is requested, or timeout expires.

Trait Implementations

impl Debug for PrerollContext

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

Formats the value using the given formatter.