add AsyncReaderStream

and replace AsyncIndexReader's stream implementation with that

Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>

src/tools/wrapped_reader_stream.rs

@@ -3,7 +3,8 @@ use std::pin::Pin;
 use std::task::{Context, Poll};
 use std::sync::mpsc::Receiver;
 
-
+use tokio::io::AsyncRead;
+use futures::ready;
 use futures::stream::Stream;
 
 use crate::tools::runtime::block_in_place;
@@ -42,6 +43,45 @@ impl<R: Read + Unpin> Stream for WrappedReaderStream<R> {
     }
 }
 
+/// Wrapper struct to convert an AsyncReader into a Stream
+pub struct AsyncReaderStream<R: AsyncRead + Unpin> {
+    reader: R,
+    buffer: Vec<u8>,
+}
+
+impl <R: AsyncRead + Unpin> AsyncReaderStream<R> {
+
+    pub fn new(reader: R) -> Self {
+        let mut buffer = Vec::with_capacity(64*1024);
+        unsafe { buffer.set_len(buffer.capacity()); }
+        Self { reader, buffer }
+    }
+
+    pub fn with_buffer_size(reader: R, buffer_size: usize) -> Self {
+        let mut buffer = Vec::with_capacity(buffer_size);
+        unsafe { buffer.set_len(buffer.capacity()); }
+        Self { reader, buffer }
+    }
+}
+
+impl<R: AsyncRead + Unpin> Stream for AsyncReaderStream<R> {
+    type Item = Result<Vec<u8>, io::Error>;
+
+    fn poll_next(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Option<Self::Item>> {
+        let this = self.get_mut();
+        match ready!(Pin::new(&mut this.reader).poll_read(cx, &mut this.buffer)) {
+            Ok(n) => {
+                if n == 0 {
+                    // EOF
+                    Poll::Ready(None)
+                } else {
+                    Poll::Ready(Some(Ok(this.buffer[..n].to_vec())))
+                }
+            }
+            Err(err) => Poll::Ready(Some(Err(err))),
+        }
+    }
+}
 
 /// Wrapper struct to convert a channel Receiver into a Stream
 pub struct StdChannelStream<T>(pub Receiver<T>);