dope_fiber/
file.rs

1//! Owned file operations backed by an installed manifold Reader.
2
3use std::{ops::ControlFlow, task};
4
5use o3::mem::{Rejected, Return};
6
7use crate::{
8    abi::{self, machine},
9    context,
10    manifold::file::read,
11};
12
13enum Stage<'p, 'd, R: Return> {
14    Request(read::Request<R>),
15    Ticket(read::Ticket<'p, 'd, R>),
16}
17
18/// Cancellation drops only the reply ticket. The Reader keeps native inputs.
19#[must_use = "a fiber does nothing unless it is driven"]
20pub struct Operation<'p, 'd, R: Return = read::Release<'d>> {
21    port: &'p read::Port<'d, R>,
22    stage: machine::Machine<Stage<'p, 'd, R>>,
23}
24
25impl<'p, 'd, R: Return> Operation<'p, 'd, R> {
26    pub fn new(port: &'p read::Port<'d, R>, request: read::Request<R>) -> Self {
27        Self {
28            port,
29            stage: machine::Machine::new(Stage::Request(request)),
30        }
31    }
32}
33
34// No field has a pinned projection; the request moves into the Reader's stable slot.
35impl<R: Return> Unpin for Operation<'_, '_, R> {}
36
37impl<'d, R: Return<Item = read::Buffer<'d>>> abi::Fiber<'d> for Operation<'_, 'd, R> {
38    type Output = Result<read::Completion<R>, Rejected<read::Request<R>, read::Admission>>;
39
40    fn poll(call: context::PollCall<'_, '_, 'd, Self>) -> task::Poll<Self::Output> {
41        let (this, cx) = call.into_parts();
42        let this = this.get_mut();
43        let waiter = cx.as_ref().completion();
44        this.stage.step(|stage| {
45            let ticket = match stage {
46                Stage::Ticket(ticket) => ticket,
47                Stage::Request(request) => match this.port.try_request(request) {
48                    Ok(ticket) => ticket,
49                    Err(cause) => return ControlFlow::Break(Err(cause)),
50                },
51            };
52            match ticket.poll(waiter) {
53                read::Poll::Pending(ticket) => ControlFlow::Continue(Stage::Ticket(ticket)),
54                read::Poll::Ready(completion) => ControlFlow::Break(Ok(completion)),
55            }
56        })
57    }
58}
dope_fiber/file.rs

dope_fiber/
file.rs
