Refactor AsyncReadLoan

src/io.rs

@@ -1,11 +1,12 @@
 use futures_lite::Stream;
 
 use crate::aliases::IoResult;
-use std::future::Future;
+use std::{future::Future, mem::MaybeUninit};
 
 pub trait BufferMut {
 	fn as_mut_ptr(&mut self) -> *mut u8;
 	fn writable_bytes(&self) -> usize;
+	fn resize_to_fit(&mut self, written_bytes: usize);
 }
 
 impl BufferMut for Vec<u8> {
@@ -14,7 +15,29 @@ impl BufferMut for Vec<u8> {
 	}
 
 	fn writable_bytes(&self) -> usize {
-		self.len()
+		self.capacity()
+	}
+
+	fn resize_to_fit(&mut self, written_bytes: usize) {
+		if written_bytes > self.capacity() {
+			panic!();
+		}
+		unsafe { self.set_len(written_bytes) };
+	}
+}
+
+fn resize_box<T>(bx: &mut Box<[T]>, size: usize) {
+	let mut bx_tmp = MaybeUninit::uninit();
+	let bx_tmp_ptr: *mut Box<[T]> = bx_tmp.as_mut_ptr();
+	let bx_tmp = unsafe {
+		bx_tmp_ptr.copy_from_nonoverlapping(bx as *const _, 1);
+		bx_tmp.assume_init()
+	};
+
+	let mut vec = bx_tmp.into_vec();
+	vec.truncate(size);
+	unsafe {
+		(bx as *mut Box<[T]>).copy_from_nonoverlapping(&vec.into_boxed_slice(), 1);
 	}
 }
 
@@ -26,21 +49,43 @@ impl BufferMut for Box<[u8]> {
 	fn writable_bytes(&self) -> usize {
 		self.len()
 	}
+
+	fn resize_to_fit(&mut self, written_bytes: usize) {
+		resize_box(self, written_bytes)
+	}
 }
 
 pub trait AsyncReadLoan {
-	fn read<B: BufferMut>(&mut self, buf: B) -> impl Future<Output = (B, IoResult<usize>)>;
+	fn read_no_resize<B: BufferMut>(
+		&mut self,
+		buf: B,
+	) -> impl Future<Output = (B, IoResult<usize>)>;
+
+	fn read<B: BufferMut>(&mut self, buf: B) -> impl Future<Output = (B, IoResult<usize>)> {
+		async {
+			let (mut buf, amt) = self.read_no_resize(buf).await;
+			let (buf, amt) = match amt {
+				Ok(amt) => (
+					{
+						buf.resize_to_fit(amt);
+						buf
+					},
+					Ok(amt),
+				),
+				Err(e) => (buf, Err(e)),
+			};
+
+			(buf, amt)
+		}
+	}
 
 	fn read_stream(&mut self) -> impl Stream<Item = IoResult<Vec<u8>>> {
 		futures_lite::stream::unfold(self, move |s| async move {
-			let (mut buf, res) = s.read(vec![0; 4096]).await;
+			let (buf, res) = s.read(vec![0; 4096]).await;
 			match res {
 				Err(e) => Some((Err(e), s)),
 				Ok(0) => None,
-				Ok(read_amt) => {
-					buf.truncate(read_amt);
-					Some((Ok(buf), s))
-				},
+				Ok(_) => Some((Ok(buf), s)),
 			}
 		})
 	}

src/io_impl/io_uring/mod.rs

@@ -16,7 +16,7 @@ use parking::Parker;
 use crate::{
 	aliases::IoResult,
 	futures::{handoff, Get, GetFut, Put},
-	io::{AsyncReadLoan, AsyncWriteLoan},
+	io::{AsyncReadLoan, AsyncWriteLoan, Buffer, BufferMut},
 };
 
 use super::IoImpl;
@@ -281,7 +281,7 @@ impl Drop for TcpStream {
 	}
 }
 impl AsyncReadLoan for TcpStream {
-	async fn read<B: crate::io::BufferMut>(&mut self, mut buf: B) -> (B, IoResult<usize>) {
+	async fn read_no_resize<B: BufferMut>(&mut self, mut buf: B) -> (B, IoResult<usize>) {
 		let res = self
 			.uring
 			.0
@@ -301,7 +301,7 @@ impl AsyncReadLoan for TcpStream {
 }
 
 impl AsyncWriteLoan for TcpStream {
-	async fn write<B: crate::io::Buffer>(&mut self, buf: B) -> (B, IoResult<usize>) {
+	async fn write<B: Buffer>(&mut self, buf: B) -> (B, IoResult<usize>) {
 		let res = self
 			.uring
 			.0

src/net.rs

@@ -22,7 +22,7 @@ impl<I: IoImpl> AsyncReadLoan for TcpStream<I>
 where
 	I::TcpStream: AsyncReadLoan,
 {
-	async fn read<B: BufferMut>(&mut self, buf: B) -> (B, IoResult<usize>) {
+	async fn read_no_resize<B: BufferMut>(&mut self, buf: B) -> (B, IoResult<usize>) {
 		self.0.read(buf).await
 	}
 }