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use crate::{Error, Result};
use anyhow::Context;
use log::{error, info};
use serde::{Deserialize, Serialize};
use serde_json::Value;
use std::collections::HashMap;
use std::sync::Arc;
use tokio::{
io::{AsyncBufRead, AsyncBufReadExt, AsyncReadExt, AsyncWrite, AsyncWriteExt},
sync::{
mpsc::{unbounded_channel, Sender, UnboundedReceiver, UnboundedSender},
Mutex,
},
};
#[derive(Debug, Clone, Deserialize, Serialize)]
pub struct Request {
#[serde(skip)]
pub back_ch: Option<Sender<Result<Response>>>,
pub seq: u64,
#[serde(rename = "type")]
pub msg_type: String,
pub command: String,
pub arguments: Option<Value>,
}
#[derive(Debug, PartialEq, Clone, Deserialize, Serialize)]
pub struct Response {
pub seq: u64,
#[serde(rename = "type")]
pub msg_type: String,
pub request_seq: u64,
pub success: bool,
pub command: String,
pub message: Option<String>,
pub body: Option<Value>,
}
#[derive(Debug, PartialEq, Clone, Deserialize, Serialize)]
pub struct Event {
pub seq: u64,
#[serde(rename = "type")]
pub msg_type: String,
pub event: String,
pub body: Option<Value>,
}
#[derive(Debug, Clone, Deserialize, Serialize)]
#[serde(untagged)]
pub enum Payload {
// type = "event"
Event(Event),
// type = "response"
Response(Response),
// type = "request"
Request(Request),
}
#[derive(Debug)]
pub struct Transport {
id: usize,
pending_requests: Mutex<HashMap<u64, Sender<Result<Response>>>>,
}
impl Transport {
pub fn start(
server_stdout: Box<dyn AsyncBufRead + Unpin + Send>,
server_stdin: Box<dyn AsyncWrite + Unpin + Send>,
id: usize,
) -> (UnboundedReceiver<Payload>, UnboundedSender<Request>) {
let (client_tx, rx) = unbounded_channel();
let (tx, client_rx) = unbounded_channel();
let transport = Self {
id,
pending_requests: Mutex::new(HashMap::default()),
};
let transport = Arc::new(transport);
tokio::spawn(Self::recv(transport.clone(), server_stdout, client_tx));
tokio::spawn(Self::send(transport, server_stdin, client_rx));
(rx, tx)
}
async fn recv_server_message(
reader: &mut Box<dyn AsyncBufRead + Unpin + Send>,
buffer: &mut String,
) -> Result<Payload> {
let mut content_length = None;
loop {
buffer.truncate(0);
reader.read_line(buffer).await?;
let header = buffer.trim();
if header.is_empty() {
break;
}
let mut parts = header.split(": ");
match (parts.next(), parts.next(), parts.next()) {
(Some("Content-Length"), Some(value), None) => {
content_length = Some(value.parse().context("invalid content length")?);
}
(Some(_), Some(_), None) => {}
_ => {
return Err(std::io::Error::new(
std::io::ErrorKind::Other,
"Failed to parse header",
)
.into());
}
}
}
let content_length = content_length.context("missing content length")?;
//TODO: reuse vector
let mut content = vec![0; content_length];
reader.read_exact(&mut content).await?;
let msg = std::str::from_utf8(&content).context("invalid utf8 from server")?;
info!("<- DAP {}", msg);
// try parsing as output (server response) or call (server request)
let output: serde_json::Result<Payload> = serde_json::from_str(msg);
Ok(output?)
}
async fn send_payload_to_server(
&self,
server_stdin: &mut Box<dyn AsyncWrite + Unpin + Send>,
req: Request,
) -> Result<()> {
let json = serde_json::to_string(&req)?;
if let Some(back) = req.back_ch {
self.pending_requests.lock().await.insert(req.seq, back);
}
self.send_string_to_server(server_stdin, json).await
}
async fn send_string_to_server(
&self,
server_stdin: &mut Box<dyn AsyncWrite + Unpin + Send>,
request: String,
) -> Result<()> {
info!("-> DAP {}", request);
// send the headers
server_stdin
.write_all(format!("Content-Length: {}\r\n\r\n", request.len()).as_bytes())
.await?;
// send the body
server_stdin.write_all(request.as_bytes()).await?;
server_stdin.flush().await?;
Ok(())
}
async fn process_server_message(
&self,
client_tx: &UnboundedSender<Payload>,
msg: Payload,
) -> Result<()> {
match msg {
Payload::Response(Response {
ref success,
ref seq,
request_seq,
ref command,
ref message,
ref body,
..
}) => {
let result = match success {
true => {
info!("<- DAP success ({}, in response to {})", seq, request_seq);
if let Payload::Response(val) = msg {
Ok(val)
} else {
unreachable!();
}
}
false => {
error!(
"<- DAP error {:?} ({:?}) for command #{} {}",
message, body, request_seq, command
);
Err(Error::Other(anyhow::format_err!("{:?}", body)))
}
};
let tx = self
.pending_requests
.lock()
.await
.remove(&request_seq)
.expect("pending_request with id not found!");
match tx.send(result).await {
Ok(_) => (),
Err(_) => error!(
"Tried sending response into a closed channel (id={:?}), original request likely timed out",
request_seq
),
};
Ok(())
}
Payload::Request(Request {
ref command,
ref seq,
..
}) => {
info!("<- DAP request {} #{}", command, seq);
client_tx.send(msg).expect("Failed to send");
Ok(())
}
Payload::Event(Event {
ref event, ref seq, ..
}) => {
info!("<- DAP event {} #{}", event, seq);
client_tx.send(msg).expect("Failed to send");
Ok(())
}
}
}
async fn recv(
transport: Arc<Self>,
mut server_stdout: Box<dyn AsyncBufRead + Unpin + Send>,
client_tx: UnboundedSender<Payload>,
) {
let mut recv_buffer = String::new();
loop {
match Self::recv_server_message(&mut server_stdout, &mut recv_buffer).await {
Ok(msg) => {
transport
.process_server_message(&client_tx, msg)
.await
.unwrap();
}
Err(err) => {
error!("err: <- {:?}", err);
break;
}
}
}
}
async fn send(
transport: Arc<Self>,
mut server_stdin: Box<dyn AsyncWrite + Unpin + Send>,
mut client_rx: UnboundedReceiver<Request>,
) {
while let Some(req) = client_rx.recv().await {
transport
.send_payload_to_server(&mut server_stdin, req)
.await
.unwrap()
}
}
}
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