// Copyright 2018 Parity Technologies (UK) Ltd.
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//! Provides the `TransportExt` trait.

use crate::core::{
    muxing::{StreamMuxer, StreamMuxerBox},
    transport::Boxed,
};
use crate::{
    bandwidth::{BandwidthLogging, BandwidthSinks},
    Transport,
};
use libp2p_identity::PeerId;
use std::sync::Arc;

/// Trait automatically implemented on all objects that implement `Transport`. Provides some
/// additional utilities.
pub trait TransportExt: Transport {
    /// Adds a layer on the `Transport` that logs all trafic that passes through the streams
    /// created by it.
    ///
    /// This method returns an `Arc<BandwidthSinks>` that can be used to retrieve the total number
    /// of bytes transferred through the streams.
    ///
    /// # Example
    ///
    /// ```
    /// use libp2p_mplex as mplex;
    /// use libp2p_noise as noise;
    /// use libp2p_tcp as tcp;
    /// use libp2p::{
    ///     core::upgrade,
    ///     identity,
    ///     TransportExt,
    ///     Transport,
    /// };
    ///
    /// let id_keys = identity::Keypair::generate_ed25519();
    ///
    /// let transport = tcp::tokio::Transport::new(tcp::Config::default().nodelay(true))
    ///     .upgrade(upgrade::Version::V1)
    ///     .authenticate(
    ///         noise::NoiseAuthenticated::xx(&id_keys)
    ///             .expect("Signing libp2p-noise static DH keypair failed."),
    ///     )
    ///     .multiplex(mplex::MplexConfig::new())
    ///     .boxed();
    ///
    /// let (transport, sinks) = transport.with_bandwidth_logging();
    /// ```
    fn with_bandwidth_logging<S>(self) -> (Boxed<(PeerId, StreamMuxerBox)>, Arc<BandwidthSinks>)
    where
        Self: Sized + Send + Unpin + 'static,
        Self::Dial: Send + 'static,
        Self::ListenerUpgrade: Send + 'static,
        Self::Error: Send + Sync,
        Self::Output: Into<(PeerId, S)>,
        S: StreamMuxer + Send + 'static,
        S::Substream: Send + 'static,
        S::Error: Send + Sync + 'static,
    {
        let sinks = BandwidthSinks::new();
        let sinks_copy = sinks.clone();
        let transport = Transport::map(self, |output, _| {
            let (peer_id, stream_muxer_box) = output.into();
            (
                peer_id,
                StreamMuxerBox::new(BandwidthLogging::new(stream_muxer_box, sinks_copy)),
            )
        })
        .boxed();
        (transport, sinks)
    }
}

impl<TTransport> TransportExt for TTransport where TTransport: Transport {}