wait for any ready stream instead of the highest priority one

This commit is contained in:
trinity-1686a 2022-06-19 17:44:07 +02:00
parent 4745e7c4ba
commit 5d7541e13a
3 changed files with 124 additions and 71 deletions

View file

@ -42,7 +42,7 @@ where
(self.clone(), None)
}
async fn deserialize_msg(ser_self: Self::SerializableSelf, stream: AssociatedStream) -> Self {
async fn deserialize_msg(ser_self: Self::SerializableSelf, _stream: AssociatedStream) -> Self {
// TODO verify no stream
ser_self
}

View file

@ -7,7 +7,7 @@ use log::{trace, warn};
use futures::channel::mpsc::{unbounded, UnboundedReceiver, UnboundedSender};
use futures::Stream;
use futures::{AsyncReadExt, AsyncWriteExt, FutureExt, StreamExt};
use futures::{AsyncReadExt, AsyncWriteExt};
use kuska_handshake::async_std::BoxStreamWrite;
use tokio::sync::mpsc;
@ -53,7 +53,8 @@ pub const PRIO_SECONDARY: RequestPriority = 0x01;
pub(crate) type RequestID = u32;
type ChunkLength = u16;
const MAX_CHUNK_LENGTH: ChunkLength = 0x4000;
const MAX_CHUNK_LENGTH: ChunkLength = 0x3FF0;
const ERROR_MARKER: ChunkLength = 0x4000;
const CHUNK_HAS_CONTINUATION: ChunkLength = 0x8000;
struct SendQueueItem {
@ -99,8 +100,29 @@ impl From<Data> for DataReader {
}
}
struct DataReaderItem {
/// a fixed size buffer containing some data, possibly padded with 0s
data: [u8; MAX_CHUNK_LENGTH as usize],
/// actuall lenght of data
len: usize,
/// whethere there may be more data comming from this stream. Can be used for some
/// optimization. It's an error to set it to false if there is more data, but it is correct
/// (albeit sub-optimal) to set it to true if there is nothing coming after
may_have_more: bool,
}
impl DataReaderItem {
fn empty_last() -> Self {
DataReaderItem {
data: [0; MAX_CHUNK_LENGTH as usize],
len: 0,
may_have_more: false,
}
}
}
impl Stream for DataReader {
type Item = ([u8; MAX_CHUNK_LENGTH as usize], usize);
type Item = DataReaderItem;
fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
match self.project() {
@ -114,7 +136,11 @@ impl Stream for DataReader {
let mut body = [0; MAX_CHUNK_LENGTH as usize];
body[..len].copy_from_slice(&data[*pos..end]);
*pos = end;
Poll::Ready(Some((body, len)))
Poll::Ready(Some(DataReaderItem {
data: body,
len,
may_have_more: end < data.len(),
}))
}
}
DataReaderProj::Streaming {
@ -154,7 +180,11 @@ impl Stream for DataReader {
let len = buf.len();
body[..len].copy_from_slice(buf);
buf.clear();
Poll::Ready(Some((body, len)))
Poll::Ready(Some(DataReaderItem {
data: body,
len,
may_have_more: !*eos,
}))
}
}
}
@ -181,6 +211,8 @@ impl SendQueue {
};
self.items[pos_prio].1.push_back(item);
}
// used only in tests. They should probably be rewriten
#[allow(dead_code)]
fn pop(&mut self) -> Option<SendQueueItem> {
match self.items.pop_front() {
None => None,
@ -196,6 +228,54 @@ impl SendQueue {
fn is_empty(&self) -> bool {
self.items.iter().all(|(_k, v)| v.is_empty())
}
// this is like an async fn, but hand implemented
fn next_ready(&mut self) -> SendQueuePollNextReady<'_> {
SendQueuePollNextReady { queue: self }
}
}
struct SendQueuePollNextReady<'a> {
queue: &'a mut SendQueue,
}
impl<'a> futures::Future for SendQueuePollNextReady<'a> {
type Output = (RequestID, DataReaderItem);
fn poll(mut self: Pin<&mut Self>, ctx: &mut Context<'_>) -> Poll<Self::Output> {
for i in 0..self.queue.items.len() {
let (_prio, items_at_prio) = &mut self.queue.items[i];
for _ in 0..items_at_prio.len() {
let mut item = items_at_prio.pop_front().unwrap();
match Pin::new(&mut item.data).poll_next(ctx) {
Poll::Pending => items_at_prio.push_back(item),
Poll::Ready(Some(data)) => {
let id = item.id;
if data.may_have_more {
self.queue.push(item);
} else {
if items_at_prio.is_empty() {
// this priority level is empty, remove it
self.queue.items.remove(i);
}
}
return Poll::Ready((id, data));
}
Poll::Ready(None) => {
if items_at_prio.is_empty() {
// this priority level is empty, remove it
self.queue.items.remove(i);
}
return Poll::Ready((item.id, DataReaderItem::empty_last()));
}
}
}
}
// TODO what do we do if self.queue is empty? We won't get scheduled again.
Poll::Pending
}
}
/// The SendLoop trait, which is implemented both by the client and the server
@ -219,77 +299,42 @@ pub(crate) trait SendLoop: Sync {
let mut sending = SendQueue::new();
let mut should_exit = false;
while !should_exit || !sending.is_empty() {
if let Ok((id, prio, data)) = msg_recv.try_recv() {
match &data {
Data::Full(data) => {
trace!("send_loop: got {}, {} bytes", id, data.len());
}
Data::Streaming(_) => {
trace!("send_loop: got {}, unknown size", id);
}
let recv_fut = msg_recv.recv();
futures::pin_mut!(recv_fut);
let send_fut = sending.next_ready();
// recv_fut is cancellation-safe according to tokio doc,
// send_fut is cancellation-safe as implemented above?
use futures::future::Either;
match futures::future::select(recv_fut, send_fut).await {
Either::Left((sth, _send_fut)) => {
if let Some((id, prio, data)) = sth {
sending.push(SendQueueItem {
id,
prio,
data: data.into(),
});
} else {
should_exit = true;
};
}
sending.push(SendQueueItem {
id,
prio,
data: data.into(),
});
} else if let Some(mut item) = sending.pop() {
trace!("send_loop: sending bytes for {}", item.id,);
Either::Right(((id, data), _recv_fut)) => {
trace!("send_loop: sending bytes for {}", id);
let data = futures::select! {
data = item.data.next().fuse() => data,
default => {
// nothing to send yet; re-schedule and find something else to do
sending.push(item);
continue;
let header_id = RequestID::to_be_bytes(id);
write.write_all(&header_id[..]).await?;
// TODO if every SendQueueItem is waiting on data, use select_all to await
// something to do
}
};
let body = &data.data[..data.len];
let header_id = RequestID::to_be_bytes(item.id);
write.write_all(&header_id[..]).await?;
let size_header = if data.may_have_more {
ChunkLength::to_be_bytes(data.len as u16 | CHUNK_HAS_CONTINUATION)
} else {
ChunkLength::to_be_bytes(data.len as u16)
};
let data = match data.as_ref() {
Some((data, len)) => &data[..*len],
None => &[],
};
if data.len() == MAX_CHUNK_LENGTH as usize {
let size_header =
ChunkLength::to_be_bytes(data.len() as u16 | CHUNK_HAS_CONTINUATION);
write.write_all(&size_header[..]).await?;
write.write_all(data).await?;
sending.push(item);
} else {
let size_header = ChunkLength::to_be_bytes(data.len() as u16);
write.write_all(&size_header[..]).await?;
write.write_all(data).await?;
}
write.flush().await?;
} else {
let sth = msg_recv.recv().await;
if let Some((id, prio, data)) = sth {
match &data {
Data::Full(data) => {
trace!("send_loop: got {}, {} bytes", id, data.len());
}
Data::Streaming(_) => {
trace!("send_loop: got {}, unknown size", id);
}
}
sending.push(SendQueueItem {
id,
prio,
data: data.into(),
});
} else {
should_exit = true;
write.write_all(body).await?;
write.flush().await?;
}
}
}

View file

@ -19,6 +19,14 @@ pub type NodeKey = sodiumoxide::crypto::sign::ed25519::SecretKey;
/// A network key
pub type NetworkKey = sodiumoxide::crypto::auth::Key;
/// A stream of associated data.
///
/// The Stream can continue after receiving an error.
/// When sent through Netapp, the Vec may be split in smaller chunk in such a way
/// consecutive Vec may get merged, but Vec and error code may not be reordered
///
/// The error code have no predefined meaning, it's up to you application to define their
/// semantic.
pub type AssociatedStream = Pin<Box<dyn Stream<Item = Vec<u8>> + Send>>;
/// Utility function: encodes any serializable value in MessagePack binary format