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

//! Objects associated with connection handling.

use bytes::Bytes;
use parking_lot::RwLock;
use tokio::{
    net::{
        tcp::{OwnedReadHalf, OwnedWriteHalf},
        TcpStream,
    },
    sync::mpsc::Sender,
    task::JoinHandle,
};

use std::{collections::HashMap, io, net::SocketAddr, ops::Not};

#[derive(Default)]
pub(crate) struct Connections(RwLock<HashMap<SocketAddr, Connection>>);

impl Connections {
    pub(crate) fn sender(&self, addr: SocketAddr) -> io::Result<Sender<Bytes>> {
        if let Some(conn) = self.0.read().get(&addr) {
            conn.sender()
        } else {
            Err(io::ErrorKind::NotConnected.into())
        }
    }

    pub(crate) fn add(&self, conn: Connection) {
        self.0.write().insert(conn.addr, conn);
    }

    pub(crate) fn senders(&self) -> Vec<(Sender<Bytes>, SocketAddr)> {
        self.0
            .read()
            .values()
            .filter_map(|conn| conn.sender().ok().map(|sender| (sender, conn.addr)))
            .collect()
    }

    pub(crate) fn is_connected(&self, addr: SocketAddr) -> bool {
        self.0.read().contains_key(&addr)
    }

    pub(crate) fn remove(&self, addr: SocketAddr) -> Option<Connection> {
        self.0.write().remove(&addr)
    }

    pub(crate) fn num_connected(&self) -> usize {
        self.0.read().len()
    }

    pub(crate) fn addrs(&self) -> Vec<SocketAddr> {
        self.0.read().keys().copied().collect()
    }
}

/// Indicates who was the initiator and who was the responder when the connection was established.
#[derive(Clone, Copy, Debug)]
pub enum ConnectionSide {
    /// The side that initiated the connection.
    Initiator,
    /// The sider that accepted the connection.
    Responder,
}

impl Not for ConnectionSide {
    type Output = Self;

    fn not(self) -> Self::Output {
        match self {
            Self::Initiator => Self::Responder,
            Self::Responder => Self::Initiator,
        }
    }
}

/// Keeps track of tasks that have been spawned for the purposes of a connection; it
/// also contains a sender that communicates with the `Writing` protocol handler.
pub struct Connection {
    /// The address of the connection.
    pub addr: SocketAddr,
    /// Kept only until the protocols are enabled (`Reading` should `take()` it).
    pub reader: Option<OwnedReadHalf>,
    /// Kept only until the protocols are enabled (`Writing` should `take()` it).
    pub writer: Option<OwnedWriteHalf>,
    /// Handles to tasks spawned by the connection.
    pub tasks: Vec<JoinHandle<()>>,
    /// Used to queue writes to the stream.
    pub outbound_message_sender: Option<Sender<Bytes>>,
    /// The connection's side in relation to the node.
    pub side: ConnectionSide,
}

impl Connection {
    /// Creates a `Connection` with placeholders for protocol-related objects.
    pub(crate) fn new(addr: SocketAddr, stream: TcpStream, side: ConnectionSide) -> Self {
        let (reader, writer) = stream.into_split();

        Self {
            addr,
            reader: Some(reader),
            writer: Some(writer),
            side,
            tasks: Default::default(),
            outbound_message_sender: Default::default(),
        }
    }

    /// Provides mutable access to the underlying reader; it should only be used in protocol definitions.
    pub fn reader(&mut self) -> &mut OwnedReadHalf {
        self.reader
            .as_mut()
            .expect("Connection's reader is not available!")
    }

    /// Provides mutable access to the underlying writer; it should only be used in protocol definitions.
    pub fn writer(&mut self) -> &mut OwnedWriteHalf {
        self.writer
            .as_mut()
            .expect("Connection's writer is not available!")
    }

    /// Returns a `Sender` for outbound messages, as long as `Writing` is enabled.
    fn sender(&self) -> io::Result<Sender<Bytes>> {
        if let Some(ref sender) = self.outbound_message_sender {
            Ok(sender.clone())
        } else {
            Err(io::ErrorKind::Unsupported.into())
        }
    }
}