1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116

use crate::channel_types::SmallReceiver;
use crate::{relay::CtrlSignal, tokio::runtime::Handle, Context};
use ockam_core::{Processor, Result};

pub struct ProcessorRelay<P>
where
    P: Processor<Context = Context>,
{
    processor: P,
    ctx: Context,
}

impl<P> ProcessorRelay<P>
where
    P: Processor<Context = Context>,
{
    pub fn new(processor: P, ctx: Context) -> Self {
        Self { processor, ctx }
    }

    #[cfg_attr(not(feature = "std"), allow(unused_mut))]
    #[cfg_attr(not(feature = "std"), allow(unused_variables))]
    async fn run(self, mut ctrl_rx: SmallReceiver<CtrlSignal>) {
        let mut ctx = self.ctx;
        let mut processor = self.processor;
        let ctx_addr = ctx.address();

        match processor.initialize(&mut ctx).await {
            Ok(()) => {}
            Err(e) => {
                error!(
                    "Failure during '{}' processor initialisation: {}",
                    ctx.address(),
                    e
                );
            }
        }

        if let Err(e) = ctx.set_ready().await {
            error!("Failed to mark processor '{}' as 'ready': {}", ctx_addr, e);
        }

        // This future encodes the main processor run loop logic
        let run_loop = async {
            loop {
                // protect against accidental async executor deadlock
                crate::tokio::task::yield_now().await;

                match processor.process(&mut ctx).await {
                    Ok(should_continue) => {
                        if !should_continue {
                            break;
                        }
                    }
                    Err(e) => {
                        #[cfg(feature = "debugger")]
                        error!(
                            "Error encountered during '{}' processing: {:?}",
                            ctx_addr, e
                        );
                        #[cfg(not(feature = "debugger"))]
                        error!("Error encountered during '{}' processing: {}", ctx_addr, e);
                    }
                }
            }

            Result::<()>::Ok(())
        };

        #[cfg(feature = "std")]
        {
            // This future resolves when a stop control signal is received
            let shutdown_signal = async { ctrl_rx.recv().await };

            // Then select over the two futures
            tokio::select! {
                _ = shutdown_signal => {
                    debug!("Shutting down processor {}", ctx_addr);
                },
                _ = run_loop => {}
            };
        }

        // TODO wait on run_loop until we have a no_std select! implementation
        #[cfg(not(feature = "std"))]
        match run_loop.await {
            Ok(_) => trace!("Processor shut down cleanly {}", ctx_addr),
            Err(err) => error!("processor run loop aborted with error: {:?}", err),
        };

        // If we reach this point the router has signalled us to shut down
        match processor.shutdown(&mut ctx).await {
            Ok(()) => {}
            Err(e) => {
                error!("Failure during '{}' processor shutdown: {}", ctx_addr, e);
            }
        }

        // Finally send the router a stop ACK -- log errors
        trace!("Sending shutdown ACK");
        if let Err(e) = ctx.send_stop_ack().await {
            error!("Error occurred during stop ACK sending: {}", e);
        }
    }

    /// Create a processor relay with two node contexts
    pub(crate) fn init(
        rt: &Handle,
        processor: P,
        ctx: Context,
        ctrl_rx: SmallReceiver<CtrlSignal>,
    ) {
        let relay = ProcessorRelay::<P>::new(processor, ctx);
        rt.spawn(relay.run(ctrl_rx));
    }
}