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use std::collections::HashMap;
use log::debug;
use crate::{Error, Notification};
type Result<T> = core::result::Result<T, Error>;
use jsonrpc_core as jsonrpc;
use serde_json::Value;
use smol::prelude::*;
use smol::{
channel::{Receiver, Sender},
io::{BufReader, BufWriter},
process::{ChildStderr, ChildStdin, ChildStdout},
Executor,
};
pub(crate) enum Payload {
Request {
chan: Sender<Result<Value>>,
value: jsonrpc::MethodCall,
},
Notification(jsonrpc::Notification),
Response(jsonrpc::Output),
}
use serde::{Deserialize, Serialize};
/// A type representing all possible values sent from the server to the client.
#[derive(Debug, PartialEq, Clone, Deserialize, Serialize)]
#[serde(deny_unknown_fields)]
#[serde(untagged)]
enum Message {
/// A regular JSON-RPC request output (single response).
Output(jsonrpc::Output),
/// A JSON-RPC request or notification.
Call(jsonrpc::Call),
}
pub(crate) struct Transport {
incoming: Sender<jsonrpc::Call>,
outgoing: Receiver<Payload>,
pending_requests: HashMap<jsonrpc::Id, Sender<Result<Value>>>,
headers: HashMap<String, String>,
writer: BufWriter<ChildStdin>,
reader: BufReader<ChildStdout>,
}
impl Transport {
pub fn start(
ex: &Executor,
reader: BufReader<ChildStdout>,
writer: BufWriter<ChildStdin>,
) -> (Receiver<jsonrpc::Call>, Sender<Payload>) {
let (incoming, rx) = smol::channel::unbounded();
let (tx, outgoing) = smol::channel::unbounded();
let transport = Self {
reader,
writer,
incoming,
outgoing,
pending_requests: Default::default(),
headers: Default::default(),
};
ex.spawn(transport.duplex()).detach();
(rx, tx)
}
async fn recv(
reader: &mut (impl AsyncBufRead + Unpin),
headers: &mut HashMap<String, String>,
) -> core::result::Result<Message, std::io::Error> {
// read headers
loop {
let mut header = String::new();
// detect pipe closed if 0
reader.read_line(&mut header).await?;
let header = header.trim();
if header.is_empty() {
break;
}
let parts: Vec<&str> = header.split(": ").collect();
if parts.len() != 2 {
return Err(std::io::Error::new(
std::io::ErrorKind::Other,
"Failed to parse header",
));
}
headers.insert(parts[0].to_string(), parts[1].to_string());
}
// find content-length
let content_length = headers.get("Content-Length").unwrap().parse().unwrap();
let mut content = vec![0; content_length];
reader.read_exact(&mut content).await?;
let msg = String::from_utf8(content).unwrap();
// read data
// try parsing as output (server response) or call (server request)
let output: serde_json::Result<Message> = serde_json::from_str(&msg);
Ok(output?)
}
pub async fn send_payload(&mut self, payload: Payload) -> anyhow::Result<()> {
match payload {
Payload::Request { chan, value } => {
self.pending_requests.insert(value.id.clone(), chan);
let json = serde_json::to_string(&value)?;
self.send(json).await
}
Payload::Notification(value) => {
let json = serde_json::to_string(&value)?;
self.send(json).await
}
Payload::Response(error) => {
let json = serde_json::to_string(&error)?;
self.send(json).await
}
}
}
pub async fn send(&mut self, request: String) -> anyhow::Result<()> {
debug!("-> {}", request);
// send the headers
self.writer
.write_all(format!("Content-Length: {}\r\n\r\n", request.len()).as_bytes())
.await?;
// send the body
self.writer.write_all(request.as_bytes()).await?;
self.writer.flush().await?;
Ok(())
}
async fn recv_msg(&mut self, msg: Message) -> anyhow::Result<()> {
match msg {
Message::Output(output) => self.recv_response(output).await?,
Message::Call(call) => {
self.incoming.send(call).await?;
// let notification = Notification::parse(&method, params);
}
};
Ok(())
}
async fn recv_response(&mut self, output: jsonrpc::Output) -> anyhow::Result<()> {
match output {
jsonrpc::Output::Success(jsonrpc::Success { id, result, .. }) => {
debug!("<- {}", result);
let tx = self
.pending_requests
.remove(&id)
.expect("pending_request with id not found!");
tx.send(Ok(result)).await?;
}
jsonrpc::Output::Failure(jsonrpc::Failure { id, error, .. }) => {
let tx = self
.pending_requests
.remove(&id)
.expect("pending_request with id not found!");
tx.send(Err(error.into())).await?;
}
msg => unimplemented!("{:?}", msg),
}
Ok(())
}
pub async fn duplex(mut self) {
use futures_util::{select, FutureExt};
loop {
select! {
// client -> server
msg = self.outgoing.next().fuse() => {
if msg.is_none() {
break;
}
let msg = msg.unwrap();
self.send_payload(msg).await.unwrap();
}
// server <- client
msg = Self::recv(&mut self.reader, &mut self.headers).fuse() => {
if msg.is_err() {
break;
}
let msg = msg.unwrap();
debug!("<- {:?}", msg);
self.recv_msg(msg).await.unwrap();
}
}
}
}
}
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