Started `Buffered<T, const SIZE: usize>`: Static buffering stream wrapper for `ESock` syncing.

Fortune for rsh's current commit: Future small blessing − 末小吉

Cargo.toml

@@ -17,7 +17,7 @@ mopa = "0.2.2"
 pin-project = "1.0.8"
 serde = { version = "1.0.126", features = ["derive"] }
 serde_cbor = "0.11.1"
-smallvec = { version = "1.6.1", features = ["union", "serde", "write"] }
+smallvec = { version = "1.6.1", features = ["union", "serde", "write", "const_generics"] }
 stackalloc = "1.1.1"
 tokio = { version = "0.2", features = ["full"] }
 tokio-uring = "0.1.0"

src/sock.rs

@@ -18,6 +18,7 @@ use bytes::Bytes;
 
 use cancel::*;
 
+mod buffered;
 pub mod enc;
 
 /// Details of a newly accepted raw socket peer.

src/sock/buffered.rs

@@ -0,0 +1,50 @@
+//! Stream buffering for sync of encrypted socked.
+use super::*;
+use smallvec::SmallVec;
+use std::io;
+use std::{
+    task::{
+	Poll, Context,
+    },
+    pin::Pin,
+};
+use bytes::{
+    Buf, BufMut,
+};
+
+/// A wrapping buffer over a writer and/or reader.
+#[pin_project]
+#[derive(Debug)]
+pub struct Buffered<T: ?Sized, const SIZE: usize>
+{
+    error: Option<io::Error>,
+    /// If an error has been set above and/or released from the above slot, set this to true.
+    /// Then all subsequent reads or writes will return a new error.
+    poisoned: bool,
+    
+    buffer: SmallVec<[u8; SIZE]>, //TODO: Can we have a non-spilling stack vec?
+    #[pin] stream: T
+}
+
+impl<T: ?Sized + AsyncWrite, const SIZE: usize> AsyncWrite for Buffered<T, SIZE>
+{
+    fn poll_write(self: Pin<&mut Self>, cx: &mut Context<'_>, buf: &[u8]) -> Poll<Result<usize, io::Error>> {
+	// TODO: Push `buf` into `self.buffer`. When `self.buffer` is full, write to `self.stream` and clear what's been written.
+	todo!()
+    }
+    fn poll_flush(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), io::Error>> {
+	todo!("Flush any remaining bytes in the buffer to `stream`")
+    }
+    fn poll_shutdown(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), io::Error>> {
+	// I think we're supposed to imply flush here?
+	/*
+	(&mut self).poll_flush(cx)?;
+	let this = self.project();
+	
+	this.stream.poll_flush(cx)?;
+	this.stream.poll_shutdown(cx)
+	 */
+	todo!("How to do the above?")
+    }
+}
+