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
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144

use core::fmt;
use std::{
    sync::{Arc, Mutex},
    task::{Context, Poll},
};

use futures::{channel::mpsc, StreamExt};
use libp2p_core::{transport::PortUse, Endpoint, Multiaddr};
use libp2p_identity::PeerId;
use libp2p_swarm::{
    self as swarm, dial_opts::DialOpts, ConnectionDenied, ConnectionId, FromSwarm,
    NetworkBehaviour, THandler, THandlerInEvent, THandlerOutEvent, ToSwarm,
};
use swarm::{
    behaviour::ConnectionEstablished, dial_opts::PeerCondition, ConnectionClosed, DialError,
    DialFailure,
};

use crate::{handler::Handler, shared::Shared, Control};

/// A generic behaviour for stream-oriented protocols.
pub struct Behaviour {
    shared: Arc<Mutex<Shared>>,
    dial_receiver: mpsc::Receiver<PeerId>,
}

impl Default for Behaviour {
    fn default() -> Self {
        Self::new()
    }
}

impl Behaviour {
    pub fn new() -> Self {
        let (dial_sender, dial_receiver) = mpsc::channel(0);

        Self {
            shared: Arc::new(Mutex::new(Shared::new(dial_sender))),
            dial_receiver,
        }
    }

    /// Obtain a new [`Control`].
    pub fn new_control(&self) -> Control {
        Control::new(self.shared.clone())
    }
}

/// The protocol is already registered.
#[derive(Debug)]
pub struct AlreadyRegistered;

impl fmt::Display for AlreadyRegistered {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "The protocol is already registered")
    }
}

impl std::error::Error for AlreadyRegistered {}

impl NetworkBehaviour for Behaviour {
    type ConnectionHandler = Handler;
    type ToSwarm = ();

    fn handle_established_inbound_connection(
        &mut self,
        connection_id: ConnectionId,
        peer: PeerId,
        _: &Multiaddr,
        _: &Multiaddr,
    ) -> Result<THandler<Self>, ConnectionDenied> {
        Ok(Handler::new(
            peer,
            self.shared.clone(),
            Shared::lock(&self.shared).receiver(peer, connection_id),
        ))
    }

    fn handle_established_outbound_connection(
        &mut self,
        connection_id: ConnectionId,
        peer: PeerId,
        _: &Multiaddr,
        _: Endpoint,
        _: PortUse,
    ) -> Result<THandler<Self>, ConnectionDenied> {
        Ok(Handler::new(
            peer,
            self.shared.clone(),
            Shared::lock(&self.shared).receiver(peer, connection_id),
        ))
    }

    fn on_swarm_event(&mut self, event: FromSwarm) {
        match event {
            FromSwarm::ConnectionEstablished(ConnectionEstablished {
                peer_id,
                connection_id,
                ..
            }) => Shared::lock(&self.shared).on_connection_established(connection_id, peer_id),
            FromSwarm::ConnectionClosed(ConnectionClosed { connection_id, .. }) => {
                Shared::lock(&self.shared).on_connection_closed(connection_id)
            }
            FromSwarm::DialFailure(DialFailure {
                peer_id: Some(peer_id),
                error:
                    error @ (DialError::Transport(_)
                    | DialError::Denied { .. }
                    | DialError::NoAddresses
                    | DialError::WrongPeerId { .. }),
                ..
            }) => {
                let reason = error.to_string(); // We can only forward the string repr but it is better than nothing.

                Shared::lock(&self.shared).on_dial_failure(peer_id, reason)
            }
            _ => {}
        }
    }

    fn on_connection_handler_event(
        &mut self,
        _peer_id: PeerId,
        _connection_id: ConnectionId,
        event: THandlerOutEvent<Self>,
    ) {
        void::unreachable(event);
    }

    fn poll(
        &mut self,
        cx: &mut Context<'_>,
    ) -> Poll<ToSwarm<Self::ToSwarm, THandlerInEvent<Self>>> {
        if let Poll::Ready(Some(peer)) = self.dial_receiver.poll_next_unpin(cx) {
            return Poll::Ready(ToSwarm::Dial {
                opts: DialOpts::peer_id(peer)
                    .condition(PeerCondition::DisconnectedAndNotDialing)
                    .build(),
            });
        }

        Poll::Pending
    }
}