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// SPDX-License-Identifier: LGPL-3.0-or-later OR MPL-2.0
// This file is a part of `unsend`.
//
// `unsend` is free software: you can redistribute it and/or modify it under the
// terms of either:
//
// * GNU Lesser General Public License as published by the Free Software Foundation, either
// version 3 of the License, or (at your option) any later version.
// * Mozilla Public License as published by the Mozilla Foundation, version 2.
// * The Patron License (https://github.com/notgull/unsend/blob/main/LICENSE-PATRON.md)
// for sponsors and contributors, who can ignore the copyleft provisions of the above licenses
// for this project.
//
// `unsend` 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 Lesser General Public License or the Mozilla Public License for more
// details.
//
// You should have received a copy of the GNU Lesser General Public License and the Mozilla
// Public License along with `unsend`. If not, see <https://www.gnu.org/licenses/>
//! A naive TCP server.
use async_io::Async;
use blocking::{unblock, Unblock};
use futures_lite::prelude::*;
use std::cell::Cell;
use std::fs::File;
use std::net::TcpListener;
use unsend::channel::channel;
use unsend::executor::Executor;
fn main() {
async_io::block_on(async {
let (tx, rx) = channel();
// A shared value that will be mutated by the tasks.
let shared = Cell::new(1);
// Spawn a task that will read from the channel and write to a log file.
let executor = Executor::new();
executor
.spawn(async move {
let file = unblock(|| File::create("log.txt")).await.unwrap();
let mut file = Unblock::new(file);
while let Ok(msg) = rx.recv().await {
let message = format!("Sent out: {}\n", msg);
file.write_all(message.as_bytes()).await.unwrap();
}
})
.detach();
executor
.run(async {
loop {
// Listen for incoming connections.
let listener = Async::<TcpListener>::bind(([0, 0, 0, 0], 3000)).unwrap();
// Accept a new connection.
let (mut stream, _) = listener.accept().await.unwrap();
// Spawn a task that will operate on the stream.
let tx = tx.clone();
let shared = &shared;
executor
.spawn(async move {
// Read a 4-byte big-endian integer from the stream.
let mut buf = [0; 4];
stream.read_exact(&mut buf).await.unwrap();
let value = u32::from_be_bytes(buf);
// Multiply it by the shared value.
let value = value * shared.get();
// Increment the shared value.
shared.set(shared.get() + 1);
// Write the value to the stream.
stream.write_all(&value.to_be_bytes()).await.unwrap();
// Send the value to be logged.
tx.send(value).unwrap();
})
.detach();
}
})
.await;
});
}
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