From 7216f0f8de011b17146cc5647c58b7e15d91125d Mon Sep 17 00:00:00 2001
From: Avril <flanchan@cumallover.me>
Date: Mon, 9 Aug 2021 19:57:24 +0100
Subject: [PATCH] Added `ReverseSink<R>`, temporary type for handling reads
 (chacha20stream currently only has a wrapper type for writes.)
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Fortune for rsh's current commit: Curse − 凶
---
 src/sock/enc.rs | 59 ++++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 54 insertions(+), 5 deletions(-)

diff --git a/src/sock/enc.rs b/src/sock/enc.rs
index fa57a40..7e79659 100644
--- a/src/sock/enc.rs
+++ b/src/sock/enc.rs
@@ -16,10 +16,17 @@ use tokio::{
 	RwLock,
     },
     io::{
-	self,
 	DuplexStream,
     },
 };
+use std::{
+    io,
+    task::{
+	Context, Poll,
+    },
+    pin::Pin,
+    marker::Unpin,
+};
 
 /// Encrypted socket information.
 #[derive(Debug)]
@@ -28,6 +35,50 @@ struct ESockInfo {
     them: Option<RsaPublicKey>,
 }
 
+/// A shitty way of reversing `AsyncSink`
+//TODO: Implement a decrypting reader in `chacha20stream`.
+#[pin_project]
+#[derive(Debug)]
+struct ReverseSink<R: ?Sized> {
+    #[pin] temp_sink: AsyncSink<DuplexStream>,
+    #[pin] rx: DuplexStream,
+    #[pin] raw: R,
+}
+
+impl<R: AsyncRead + ?Sized> AsyncRead for ReverseSink<R>
+{
+    fn poll_read(self: Pin<&mut Self>, cx: &mut Context<'_>, buf: &mut [u8]) -> Poll<io::Result<usize>> {
+	let proj = self.project();
+	use futures::ready;
+	macro_rules! try_ready {
+	    ($poll_res:expr) => {
+		match ready!($poll_res) {
+		    Ok(v) => v,
+		    Err(e) => return Poll::Ready(Err(e)),
+		}
+	    }
+	}
+	alloc_local_bytes(buf.len(), |temp_buf| -> Poll<io::Result<usize>> {
+	    //XXX: Does this work? I dunno... Maybe just pin and poll a local `async{}` block.
+
+	    // Read encrypted bytes into `temp_buf`.
+	    let filled_buffer: &[u8] = try_ready!(proj.raw.poll_read(cx, temp_buf).map_ok(|read| { 
+		&temp_buf[..read]
+	    }));
+	    
+	    // Sink the `filled_buffer`.
+	    let sunk: usize = try_ready!(proj.temp_sink.poll_write(cx, filled_buffer));
+	    debug_assert_eq!(sunk, filled_buffer.len());
+
+	    // Ready from the `rx`.
+	    let bytes_read: usize = try_ready!(proj.rx.poll_read(cx, &mut buf[..sunk]));
+	    debug_assert_eq!(bytes_read, sunk);
+	    
+	    Poll::Ready(Ok(bytes_read))
+	})
+    }
+}
+
 /// A tx+rx socket.
 #[pin_project]
 #[derive(Debug)]
@@ -51,8 +102,6 @@ pub struct ESockWriteHalf<W>(Arc<ESockInfo>, #[pin] AsyncSink<W>);
 #[derive(Debug)]
 pub struct ESockReadHalf<R>(
     Arc<ESockInfo>,
-    
-    #[pin] R, // read from this (raw.)
-    #[pin] AsyncSink<DuplexStream>, // sink raw from `R`  here, outputs decrypted bytes into next.
-    #[pin] DuplexStream, // read decrypted bytes from here.
+
+    #[pin] ReverseSink<R>,
 );