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
145
146
147
148
149
// This file is part of Substrate.

// Copyright (C) Parity Technologies (UK) Ltd.
// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.

use futures::{
	prelude::*,
	ready,
	task::{Context, Poll},
};
use libp2p::{core::transport::timeout::TransportTimeout, Transport};
use std::{io, pin::Pin, time::Duration};

/// Timeout after which a connection attempt is considered failed. Includes the WebSocket HTTP
/// upgrading.
const CONNECT_TIMEOUT: Duration = Duration::from_secs(20);

pub(crate) fn initialize_transport() -> Result<WsTrans, io::Error> {
	let transport = {
		let tcp_transport = libp2p::tcp::tokio::Transport::new(libp2p::tcp::Config::new());
		let inner = libp2p::dns::tokio::Transport::system(tcp_transport)?;
		libp2p::websocket::framed::WsConfig::new(inner).and_then(|connec, _| {
			let connec = connec
				.with(|item| {
					let item = libp2p::websocket::framed::OutgoingData::Binary(item);
					future::ready(Ok::<_, io::Error>(item))
				})
				.try_filter_map(|item| async move {
					if let libp2p::websocket::framed::Incoming::Data(data) = item {
						Ok(Some(data.into_bytes()))
					} else {
						Ok(None)
					}
				});
			future::ready(Ok::<_, io::Error>(connec))
		})
	};

	Ok(TransportTimeout::new(
		transport.map(|out, _| {
			let out = out
				.map_err(|err| io::Error::new(io::ErrorKind::Other, err))
				.sink_map_err(|err| io::Error::new(io::ErrorKind::Other, err));
			Box::pin(out) as Pin<Box<_>>
		}),
		CONNECT_TIMEOUT,
	)
	.boxed())
}

/// A trait that implements `Stream` and `Sink`.
pub(crate) trait StreamAndSink<I>: Stream + Sink<I> {}
impl<T: ?Sized + Stream + Sink<I>, I> StreamAndSink<I> for T {}

/// A type alias for the WebSocket transport.
pub(crate) type WsTrans = libp2p::core::transport::Boxed<
	Pin<
		Box<
			dyn StreamAndSink<Vec<u8>, Item = Result<Vec<u8>, io::Error>, Error = io::Error> + Send,
		>,
	>,
>;

/// Wraps around an `AsyncWrite` and implements `Sink`. Guarantees that each item being sent maps
/// to one call of `write`.
#[pin_project::pin_project]
pub(crate) struct StreamSink<T>(#[pin] T, Option<Vec<u8>>);

impl<T> From<T> for StreamSink<T> {
	fn from(inner: T) -> StreamSink<T> {
		StreamSink(inner, None)
	}
}

impl<T: AsyncRead> Stream for StreamSink<T> {
	type Item = Result<Vec<u8>, io::Error>;

	fn poll_next(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Option<Self::Item>> {
		let this = self.project();
		let mut buf = vec![0; 128];
		match ready!(AsyncRead::poll_read(this.0, cx, &mut buf)) {
			Ok(0) => Poll::Ready(None),
			Ok(n) => {
				buf.truncate(n);
				Poll::Ready(Some(Ok(buf)))
			},
			Err(err) => Poll::Ready(Some(Err(err))),
		}
	}
}

impl<T: AsyncWrite> StreamSink<T> {
	fn poll_flush_buffer(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Result<(), io::Error>> {
		let this = self.project();

		if let Some(buffer) = this.1 {
			if ready!(this.0.poll_write(cx, &buffer[..]))? != buffer.len() {
				log::error!(target: "telemetry",
					"Detected some internal buffering happening in the telemetry");
				let err = io::Error::new(io::ErrorKind::Other, "Internal buffering detected");
				return Poll::Ready(Err(err))
			}
		}

		*this.1 = None;
		Poll::Ready(Ok(()))
	}
}

impl<T: AsyncWrite> Sink<Vec<u8>> for StreamSink<T> {
	type Error = io::Error;

	fn poll_ready(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Result<(), Self::Error>> {
		ready!(StreamSink::poll_flush_buffer(self, cx))?;
		Poll::Ready(Ok(()))
	}

	fn start_send(self: Pin<&mut Self>, item: Vec<u8>) -> Result<(), Self::Error> {
		let this = self.project();
		debug_assert!(this.1.is_none());
		*this.1 = Some(item);
		Ok(())
	}

	fn poll_flush(mut self: Pin<&mut Self>, cx: &mut Context) -> Poll<Result<(), Self::Error>> {
		ready!(self.as_mut().poll_flush_buffer(cx))?;
		let this = self.project();
		AsyncWrite::poll_flush(this.0, cx)
	}

	fn poll_close(mut self: Pin<&mut Self>, cx: &mut Context) -> Poll<Result<(), Self::Error>> {
		ready!(self.as_mut().poll_flush_buffer(cx))?;
		let this = self.project();
		AsyncWrite::poll_close(this.0, cx)
	}
}