refactor: remove an unsafe and some boxing (denoland#4398)

cli/http_util.rs

@@ -195,7 +195,7 @@ impl AsyncRead for HttpBody {
       let n = min(buf.len(), chunk.len() - inner.pos);
       {
         let rest = &chunk[inner.pos..];
-        buf[..n].clone_from_slice(&rest[..n]);
+        buf[..n].copy_from_slice(&rest[..n]);
       }
       inner.pos += n;
       if inner.pos == chunk.len() {
@@ -208,31 +208,29 @@ impl AsyncRead for HttpBody {
       assert_eq!(inner.pos, 0);
     }
 
-    let chunk_future = &mut inner.response.chunk();
-    // Safety: `chunk_future` lives only for duration of this poll. So, it doesn't move.
-    let chunk_future = unsafe { Pin::new_unchecked(chunk_future) };
-    match chunk_future.poll(cx) {
-      Poll::Ready(Err(e)) => {
-        Poll::Ready(Err(io::Error::new(io::ErrorKind::Other, e)))
-      }
-      Poll::Ready(Ok(Some(chunk))) => {
+    let chunk_future = inner.response.chunk();
+    futures::pin_mut!(chunk_future);
+
+    let result = match futures::ready!(chunk_future.poll(cx)) {
+      Err(e) => Err(io::Error::new(io::ErrorKind::Other, e)),
+      Ok(Some(chunk)) => {
         debug!(
           "HttpBody Real Read buf {} chunk {} pos {}",
           buf.len(),
           chunk.len(),
           inner.pos
         );
         let n = min(buf.len(), chunk.len());
-        buf[..n].clone_from_slice(&chunk[..n]);
+        buf[..n].copy_from_slice(&chunk[..n]);
         if buf.len() < chunk.len() {
           inner.pos = n;
           inner.chunk = Some(chunk);
         }
-        Poll::Ready(Ok(n))
+        Ok(n)
       }
-      Poll::Ready(Ok(None)) => Poll::Ready(Ok(0)),
-      Poll::Pending => Poll::Pending,
-    }
+      Ok(None) => Ok(0),
+    };
+    result.into()
   }
 }
 

cli/ops/io.rs

@@ -156,6 +156,12 @@ pub enum StreamResource {
   ChildStderr(tokio::process::ChildStderr),
 }
 
+trait UnpinAsyncRead: AsyncRead + Unpin {}
+trait UnpinAsyncWrite: AsyncWrite + Unpin {}
+
+impl<T: AsyncRead + Unpin> UnpinAsyncRead for T {}
+impl<T: AsyncWrite + Unpin> UnpinAsyncWrite for T {}
+
 /// `DenoAsyncRead` is the same as the `tokio_io::AsyncRead` trait
 /// but uses an `OpError` error instead of `std::io:Error`
 pub trait DenoAsyncRead {
@@ -173,19 +179,18 @@ impl DenoAsyncRead for StreamResource {
     buf: &mut [u8],
   ) -> Poll<Result<usize, OpError>> {
     use StreamResource::*;
-    let mut f: Pin<Box<dyn AsyncRead>> = match self {
-      FsFile(f, _) => Box::pin(f),
-      Stdin(f, _) => Box::pin(f),
-      TcpStream(f) => Box::pin(f),
-      ClientTlsStream(f) => Box::pin(f),
-      ServerTlsStream(f) => Box::pin(f),
-      ChildStdout(f) => Box::pin(f),
-      ChildStderr(f) => Box::pin(f),
-      HttpBody(f) => Box::pin(f),
+    let f: &mut dyn UnpinAsyncRead = match self {
+      FsFile(f, _) => f,
+      Stdin(f, _) => f,
+      TcpStream(f) => f,
+      ClientTlsStream(f) => f,
+      ServerTlsStream(f) => f,
+      ChildStdout(f) => f,
+      ChildStderr(f) => f,
+      HttpBody(f) => f,
       _ => return Err(OpError::bad_resource_id()).into(),
     };
-
-    let v = ready!(f.as_mut().poll_read(cx, buf))?;
+    let v = ready!(Pin::new(f).poll_read(cx, buf))?;
     Ok(v).into()
   }
 }
@@ -252,35 +257,35 @@ impl DenoAsyncWrite for StreamResource {
     buf: &[u8],
   ) -> Poll<Result<usize, OpError>> {
     use StreamResource::*;
-    let mut f: Pin<Box<dyn AsyncWrite>> = match self {
-      FsFile(f, _) => Box::pin(f),
-      Stdout(f) => Box::pin(f),
-      Stderr(f) => Box::pin(f),
-      TcpStream(f) => Box::pin(f),
-      ClientTlsStream(f) => Box::pin(f),
-      ServerTlsStream(f) => Box::pin(f),
-      ChildStdin(f) => Box::pin(f),
+    let f: &mut dyn UnpinAsyncWrite = match self {
+      FsFile(f, _) => f,
+      Stdout(f) => f,
+      Stderr(f) => f,
+      TcpStream(f) => f,
+      ClientTlsStream(f) => f,
+      ServerTlsStream(f) => f,
+      ChildStdin(f) => f,
       _ => return Err(OpError::bad_resource_id()).into(),
     };
 
-    let v = ready!(f.as_mut().poll_write(cx, buf))?;
+    let v = ready!(Pin::new(f).poll_write(cx, buf))?;
     Ok(v).into()
   }
 
   fn poll_flush(&mut self, cx: &mut Context) -> Poll<Result<(), OpError>> {
     use StreamResource::*;
-    let mut f: Pin<Box<dyn AsyncWrite>> = match self {
-      FsFile(f, _) => Box::pin(f),
-      Stdout(f) => Box::pin(f),
-      Stderr(f) => Box::pin(f),
-      TcpStream(f) => Box::pin(f),
-      ClientTlsStream(f) => Box::pin(f),
-      ServerTlsStream(f) => Box::pin(f),
-      ChildStdin(f) => Box::pin(f),
+    let f: &mut dyn UnpinAsyncWrite = match self {
+      FsFile(f, _) => f,
+      Stdout(f) => f,
+      Stderr(f) => f,
+      TcpStream(f) => f,
+      ClientTlsStream(f) => f,
+      ServerTlsStream(f) => f,
+      ChildStdin(f) => f,
       _ => return Err(OpError::bad_resource_id()).into(),
     };
 
-    ready!(f.as_mut().poll_flush(cx))?;
+    ready!(Pin::new(f).poll_flush(cx))?;
     Ok(()).into()
   }