138 lines
3.9 KiB
Rust
138 lines
3.9 KiB
Rust
use std::collections::HashMap;
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use std::sync::Arc;
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use async_trait::async_trait;
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use bytes::Bytes;
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use log::*;
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use futures::AsyncReadExt;
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use tokio::sync::mpsc;
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use crate::error::*;
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use crate::send::*;
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use crate::stream::*;
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/// Structure to warn when the sender is dropped before end of stream was reached, like when
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/// connection to some remote drops while transmitting data
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struct Sender {
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inner: Option<mpsc::UnboundedSender<Packet>>,
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}
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impl Sender {
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fn new(inner: mpsc::UnboundedSender<Packet>) -> Self {
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Sender { inner: Some(inner) }
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}
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fn send(&self, packet: Packet) {
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let _ = self.inner.as_ref().unwrap().send(packet);
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}
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fn end(&mut self) {
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self.inner = None;
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}
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}
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impl Drop for Sender {
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fn drop(&mut self) {
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if let Some(inner) = self.inner.take() {
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let _ = inner.send(Err(std::io::Error::new(
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std::io::ErrorKind::BrokenPipe,
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"Netapp connection dropped before end of stream",
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)));
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}
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}
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}
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/// The RecvLoop trait, which is implemented both by the client and the server
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/// connection objects (ServerConn and ClientConn) adds a method `.recv_loop()`
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/// and a prototype of a handler for received messages `.recv_handler()` that
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/// must be filled by implementors. `.recv_loop()` receives messages in a loop
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/// according to the protocol defined above: chunks of message in progress of being
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/// received are stored in a buffer, and when the last chunk of a message is received,
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/// the full message is passed to the receive handler.
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#[async_trait]
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pub(crate) trait RecvLoop: Sync + 'static {
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fn recv_handler(self: &Arc<Self>, id: RequestID, stream: ByteStream);
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async fn recv_loop<R>(self: Arc<Self>, mut read: R, debug_name: String) -> Result<(), Error>
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where
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R: AsyncReadExt + Unpin + Send + Sync,
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{
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let mut streams: HashMap<RequestID, Sender> = HashMap::new();
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loop {
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trace!(
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"recv_loop({}): in_progress = {:?}",
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debug_name,
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streams.iter().map(|(id, _)| id).collect::<Vec<_>>()
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);
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let mut header_id = [0u8; RequestID::BITS as usize / 8];
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match read.read_exact(&mut header_id[..]).await {
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Ok(_) => (),
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Err(e) if e.kind() == std::io::ErrorKind::UnexpectedEof => break,
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Err(e) => return Err(e.into()),
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};
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let id = RequestID::from_be_bytes(header_id);
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let mut header_size = [0u8; ChunkLength::BITS as usize / 8];
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read.read_exact(&mut header_size[..]).await?;
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let size = ChunkLength::from_be_bytes(header_size);
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let has_cont = (size & CHUNK_HAS_CONTINUATION) != 0;
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let is_error = (size & ERROR_MARKER) != 0;
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let size = (size & CHUNK_LENGTH_MASK) as usize;
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let mut next_slice = vec![0; size as usize];
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read.read_exact(&mut next_slice[..]).await?;
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let packet = if is_error {
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let kind = u8_to_io_errorkind(next_slice[0]);
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let msg =
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std::str::from_utf8(&next_slice[1..]).unwrap_or("<invalid utf8 error message>");
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debug!("recv_loop({}): got id {}, error {:?}: {}", debug_name, id, kind, msg);
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Some(Err(std::io::Error::new(kind, msg.to_string())))
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} else {
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trace!(
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"recv_loop({}): got id {}, size {}, has_cont {}",
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debug_name,
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id,
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size,
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has_cont
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);
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if !next_slice.is_empty() {
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Some(Ok(Bytes::from(next_slice)))
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} else {
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None
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}
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};
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let mut sender = if let Some(send) = streams.remove(&(id)) {
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send
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} else {
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let (send, recv) = mpsc::unbounded_channel();
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trace!("recv_loop({}): id {} is new channel", debug_name, id);
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self.recv_handler(
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id,
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Box::pin(tokio_stream::wrappers::UnboundedReceiverStream::new(recv)),
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);
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Sender::new(send)
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};
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if let Some(packet) = packet {
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// If we cannot put packet in channel, it means that the
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// receiving end of the channel is disconnected.
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// We still need to reach eos before dropping this sender
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let _ = sender.send(packet);
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}
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if has_cont {
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assert!(!is_error);
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streams.insert(id, sender);
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} else {
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trace!("recv_loop({}): close channel id {}", debug_name, id);
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sender.end();
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}
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}
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Ok(())
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}
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}
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