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use futures::{
io::{AsyncReadExt, AsyncWriteExt},
try_join,
};
use interprocess::os::windows::named_pipe::{tokio::*, PipeListenerOptions};
use std::{error::Error, ffi::OsStr, io};
use tokio::sync::oneshot::Sender;
pub async fn main(notify: Sender<()>) -> Result<(), Box<dyn Error>> {
// Describe the things we do when we've got a connection ready.
async fn handle_conn(conn: DuplexBytePipeStream) -> io::Result<()> {
// Split the connection into two halves to process
// received and sent data concurrently.
let (mut reader, mut writer) = conn.split();
// Allocate a sizeable buffer for reading.
// This size should be enough and should be easy to find for the allocator.
let mut buffer = String::with_capacity(128);
// Describe the write operation as first writing our whole message, and
// then shutting down the write half to send an EOF to help the other
// side determine the end of the transmission.
let write = async {
writer.write_all(b"Hello from server!").await?;
writer.close().await?;
Ok(())
};
// Describe the read operation as reading into our big buffer.
let read = reader.read_to_string(&mut buffer);
// Run both the write-and-send-EOF operation and the read operation concurrently.
try_join!(read, write)?;
// Dispose of our connection right now and not a moment later because I want to!
drop((reader, writer));
// Produce our output!
println!("Client answered: {}", buffer.trim());
Ok(())
}
static PIPE_NAME: &str = "Example";
// Create our listener. In a more robust program, we'd check for an
// existing socket file that has not been deleted for whatever reason,
// ensure it's a socket file and not a normal file, and delete it.
let listener = PipeListenerOptions::new()
.name(OsStr::new(PIPE_NAME))
.create_tokio::<DuplexBytePipeStream>()?;
// Stand-in for the syncronization used, if any, between the client and the server.
let _ = notify.send(());
println!(r"Server running at \\.\pipe\{}", PIPE_NAME);
// Set up our loop boilerplate that processes our incoming connections.
loop {
// Sort out situations when establishing an incoming connection caused an error.
let conn = match listener.accept().await {
Ok(c) => c,
Err(e) => {
eprintln!("There was an error with an incoming connection: {}", e);
continue;
}
};
// Spawn new parallel asynchronous tasks onto the Tokio runtime
// and hand the connection over to them so that multiple clients
// could be processed simultaneously in a lightweight fashion.
tokio::spawn(async move {
// The outer match processes errors that happen when we're
// connecting to something. The inner if-let processes errors that
// happen during the connection.
if let Err(e) = handle_conn(conn).await {
eprintln!("error while handling connection: {}", e);
}
});
}
}