overnet_core/proxy/handle/
signals.rs

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// Copyright 2021 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

use super::ReadValue;
use fidl::{HandleRef, Signals};
use fidl_fuchsia_overnet_protocol::{SignalUpdate, Signals as WireSignals};
use fuchsia_async::OnSignalsRef;
use futures::FutureExt;
use std::task::{Context, Poll};
use zx_status;

const POLLED_SIGNALS: Signals = Signals::from_bits_truncate(
    Signals::USER_0.bits()
        | Signals::USER_1.bits()
        | Signals::USER_2.bits()
        | Signals::USER_3.bits()
        | Signals::USER_4.bits()
        | Signals::USER_5.bits()
        | Signals::USER_6.bits()
        | Signals::USER_7.bits(),
);

#[derive(Default)]
pub(crate) struct Collector<'a> {
    on_signals: Option<OnSignalsRef<'a>>,
    shutdown: bool,
}

impl<'h> Collector<'h> {
    pub(crate) fn after_read<'ctx>(
        &mut self,
        ctx: &mut Context<'ctx>,
        hdl: HandleRef<'h>,
        read_result: Poll<Result<(), zx_status::Status>>,
        do_peer_closed: bool,
    ) -> Poll<Result<ReadValue, zx_status::Status>> {
        match read_result {
            Poll::Ready(Ok(())) => Poll::Ready(Ok(ReadValue::Message)),
            Poll::Ready(Err(e)) => Poll::Ready(Err(e)),
            Poll::Pending => {
                if self.shutdown {
                    return Poll::Ready(Err(zx_status::Status::PEER_CLOSED));
                }

                let signals = if do_peer_closed {
                    POLLED_SIGNALS | Signals::OBJECT_PEER_CLOSED
                } else {
                    POLLED_SIGNALS
                };

                let mut on_signals = self
                    .on_signals
                    .take()
                    .unwrap_or_else(|| OnSignalsRef::new(hdl.clone(), signals));
                match on_signals.poll_unpin(ctx) {
                    Poll::Ready(Ok(mut signals)) => {
                        self.shutdown =
                            self.shutdown || signals.contains(Signals::OBJECT_PEER_CLOSED);
                        signals.remove(Signals::OBJECT_PEER_CLOSED);
                        if signals.is_empty() {
                            Poll::Ready(Err(zx_status::Status::PEER_CLOSED))
                        } else {
                            hdl.signal(signals, Signals::empty())?;
                            Poll::Ready(Ok(ReadValue::SignalUpdate(SignalUpdate {
                                assert_signals: Some(to_wire_signals(signals)),
                                ..Default::default()
                            })))
                        }
                    }
                    Poll::Ready(Err(e)) => Poll::Ready(Err(e)),
                    Poll::Pending => {
                        self.on_signals = Some(on_signals);
                        Poll::Pending
                    }
                }
            }
        }
    }
}

fn to_wire_signals(signals: Signals) -> WireSignals {
    let mut out = WireSignals::empty();
    if signals.contains(Signals::USER_0) {
        out.insert(WireSignals::USER_0);
    }
    if signals.contains(Signals::USER_1) {
        out.insert(WireSignals::USER_1);
    }
    if signals.contains(Signals::USER_2) {
        out.insert(WireSignals::USER_2);
    }
    if signals.contains(Signals::USER_3) {
        out.insert(WireSignals::USER_3);
    }
    if signals.contains(Signals::USER_4) {
        out.insert(WireSignals::USER_4);
    }
    if signals.contains(Signals::USER_5) {
        out.insert(WireSignals::USER_5);
    }
    if signals.contains(Signals::USER_6) {
        out.insert(WireSignals::USER_6);
    }
    if signals.contains(Signals::USER_7) {
        out.insert(WireSignals::USER_7);
    }
    out
}

pub(crate) fn from_wire_signals(signals: WireSignals) -> Signals {
    let mut out = Signals::empty();
    if signals.contains(WireSignals::USER_0) {
        out.insert(Signals::USER_0);
    }
    if signals.contains(WireSignals::USER_1) {
        out.insert(Signals::USER_1);
    }
    if signals.contains(WireSignals::USER_2) {
        out.insert(Signals::USER_2);
    }
    if signals.contains(WireSignals::USER_3) {
        out.insert(Signals::USER_3);
    }
    if signals.contains(WireSignals::USER_4) {
        out.insert(Signals::USER_4);
    }
    if signals.contains(WireSignals::USER_5) {
        out.insert(Signals::USER_5);
    }
    if signals.contains(WireSignals::USER_6) {
        out.insert(Signals::USER_6);
    }
    if signals.contains(WireSignals::USER_7) {
        out.insert(Signals::USER_7);
    }
    out
}