Struct SpscHandle 

pub struct SpscHandle { /* private fields */ }

Application-side SPSC SHM handle.

Connect with SpscHandle::connect using the same name passed to SpscFace::create in the engine process.

Set a CancellationToken via [set_cancel] to abort recv/send when the router’s control face disconnects (the O_RDWR FIFO trick means EOF detection alone is unreliable).

Implementations

impl SpscHandle

pub fn connect(name: &str) -> Result<Self, ShmError>

Open the SHM region created by the engine and set up the wakeup mechanism.

pub fn set_cancel(&mut self, cancel: CancellationToken)

Attach a cancellation token (typically a child of the control face’s lifecycle token). When cancelled, recv() returns None and send() returns Err.

pub async fn send(&self, pkt: Bytes) -> Result<(), ShmError>

Send a packet to the engine (enqueue in the a2e ring).

Yields cooperatively if the ring is full (backpressure from the engine). Returns Err(Closed) if the cancellation token fires (engine dead).

Uses a wall-clock deadline so backpressure tolerance is independent of system scheduling speed (the old yield-counter approach returned Closed after ~100k yields ≈ 1s on fast machines, but could be much shorter under heavy Tokio contention — falsely killing the caller).

pub async fn recv(&self) -> Option<Bytes>

Receive a packet from the engine (dequeue from the e2a ring).

Returns None when the engine face has been dropped or the cancellation token fires.