tari_comms 5.2.1

A peer-to-peer messaging system
Documentation 
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// Copyright 2019, The Tari Project
//
// Redistribution and use in source and binary forms, with or without modification, are permitted provided that the
// following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following
// disclaimer.
//
// 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the
// following disclaimer in the documentation and/or other materials provided with the distribution.
//
// 3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote
// products derived from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
// INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
// WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
// USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

use std::sync::Arc;

use tokio::sync::{broadcast, mpsc, oneshot};

use super::{error::ConnectionManagerError, peer_connection::PeerConnection};
use crate::{
    connection_manager::manager::{ConnectionManagerEvent, ListenerInfo},
    peer_manager::NodeId,
};

/// Requests which are handled by the ConnectionManagerService
#[derive(Debug)]
pub enum ConnectionManagerRequest {
    /// Dial a given peer by node id.
    DialPeer {
        node_id: NodeId,
        reply_tx: Option<oneshot::Sender<Result<PeerConnection, ConnectionManagerError>>>,
    },
    /// Cancels a pending dial if one exists
    CancelDial(NodeId),
    /// Register a oneshot to get triggered when the node is listening, or has failed to listen
    NotifyListening(oneshot::Sender<ListenerInfo>),
}

/// Responsible for constructing requests to the ConnectionManagerService
#[derive(Clone)]
pub struct ConnectionManagerRequester {
    sender: mpsc::Sender<ConnectionManagerRequest>,
    event_tx: broadcast::Sender<Arc<ConnectionManagerEvent>>,
}

impl ConnectionManagerRequester {
    /// Create a new ConnectionManagerRequester
    pub fn new(
        sender: mpsc::Sender<ConnectionManagerRequest>,
        event_tx: broadcast::Sender<Arc<ConnectionManagerEvent>>,
    ) -> Self {
        Self { sender, event_tx }
    }
}

impl ConnectionManagerRequester {
    /// Returns a new ConnectionManagerEvent subscription
    pub fn get_event_subscription(&self) -> broadcast::Receiver<Arc<ConnectionManagerEvent>> {
        self.event_tx.subscribe()
    }

    /// Returns a ConnectionManagerEvent publisher.
    ///
    /// The CommsBuilder uses to make the publisher available to the connection manager.
    pub(crate) fn get_event_publisher(&self) -> broadcast::Sender<Arc<ConnectionManagerEvent>> {
        self.event_tx.clone()
    }

    /// Attempt to connect to a remote peer
    pub async fn dial_peer(&mut self, node_id: NodeId) -> Result<PeerConnection, ConnectionManagerError> {
        let (reply_tx, reply_rx) = oneshot::channel();
        self.send_dial_peer(node_id, Some(reply_tx)).await?;
        reply_rx
            .await
            .map_err(|_| ConnectionManagerError::ActorRequestCanceled)?
    }

    /// Send instruction to ConnectionManager to dial a peer and return the result on the given oneshot
    pub async fn cancel_dial(&mut self, node_id: NodeId) -> Result<(), ConnectionManagerError> {
        self.sender
            .send(ConnectionManagerRequest::CancelDial(node_id))
            .await
            .map_err(|_| ConnectionManagerError::SendToActorFailed)?;
        Ok(())
    }

    /// Send instruction to ConnectionManager to dial a peer and return the result on the given oneshot
    pub(crate) async fn send_dial_peer(
        &mut self,
        node_id: NodeId,
        reply_tx: Option<oneshot::Sender<Result<PeerConnection, ConnectionManagerError>>>,
    ) -> Result<(), ConnectionManagerError> {
        self.sender
            .send(ConnectionManagerRequest::DialPeer { node_id, reply_tx })
            .await
            .map_err(|_| ConnectionManagerError::SendToActorFailed)?;
        Ok(())
    }

    /// Return the ListenerInfo for the configured listener once the listener(s) are bound to the socket.
    ///
    /// This is useful when using "assigned port" addresses, such as /ip4/0.0.0.0/tcp/0 or /memory/0 for listening and
    /// you wish to know the final assigned port.
    pub async fn wait_until_listening(&mut self) -> Result<ListenerInfo, ConnectionManagerError> {
        let (reply_tx, reply_rx) = oneshot::channel();
        self.sender
            .send(ConnectionManagerRequest::NotifyListening(reply_tx))
            .await
            .map_err(|_| ConnectionManagerError::SendToActorFailed)?;
        reply_rx.await.map_err(|_| ConnectionManagerError::ActorRequestCanceled)
    }
}