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// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements. See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership. The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License. You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied. See the License for the
// specific language governing permissions and limitations
// under the License.
use std::io;
use std::ops::RangeBounds;
use std::pin::Pin;
use std::task::ready;
use std::task::Context;
use std::task::Poll;
use bytes::Bytes;
use futures::Stream;
use futures::StreamExt;
use crate::raw::*;
use crate::*;
/// FuturesBytesStream is the adapter of [`Stream`] generated by [`Reader::into_bytes_stream`].
///
/// Users can use this adapter in cases where they need to use [`Stream`] trait. FuturesBytesStream
/// reuses the same concurrent and chunk settings from [`Reader`].
///
/// FuturesStream also implements [`Unpin`], [`Send`] and [`Sync`].
pub struct FuturesBytesStream {
stream: BufferStream,
buf: Buffer,
}
/// Safety: FuturesBytesStream only exposes `&mut self` to the outside world,
unsafe impl Sync for FuturesBytesStream {}
impl FuturesBytesStream {
/// NOTE: don't allow users to create FuturesStream directly.
#[inline]
pub(crate) fn new(r: oio::Reader, options: OpReader, range: impl RangeBounds<u64>) -> Self {
let stream = BufferStream::new(r, options, range);
FuturesBytesStream {
stream,
buf: Buffer::new(),
}
}
}
impl Stream for FuturesBytesStream {
type Item = io::Result<Bytes>;
fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
let this = self.get_mut();
loop {
// Consume current buffer
if let Some(bs) = Iterator::next(&mut this.buf) {
return Poll::Ready(Some(Ok(bs)));
}
this.buf = match ready!(this.stream.poll_next_unpin(cx)) {
Some(Ok(buf)) => buf,
Some(Err(err)) => return Poll::Ready(Some(Err(format_std_io_error(err)))),
None => return Poll::Ready(None),
};
}
}
}
#[cfg(test)]
mod tests {
use std::sync::Arc;
use bytes::Bytes;
use futures::TryStreamExt;
use pretty_assertions::assert_eq;
use super::*;
#[test]
fn test_trait() {
let v = FuturesBytesStream::new(Arc::new(Buffer::new()), OpReader::new(), 4..8);
let _: Box<dyn Unpin + MaybeSend + Sync + 'static> = Box::new(v);
}
#[tokio::test]
async fn test_futures_bytes_stream() {
let r: oio::Reader = Arc::new(Buffer::from(vec![
Bytes::from("Hello"),
Bytes::from("World"),
]));
let s = FuturesBytesStream::new(r, OpReader::new(), 4..8);
let bufs: Vec<Bytes> = s.try_collect().await.unwrap();
assert_eq!(&bufs[0], "o".as_bytes());
assert_eq!(&bufs[1], "Wor".as_bytes());
}
#[tokio::test]
async fn test_futures_bytes_stream_with_concurrent() {
let r: oio::Reader = Arc::new(Buffer::from(vec![
Bytes::from("Hello"),
Bytes::from("World"),
]));
let s = FuturesBytesStream::new(r, OpReader::new().with_concurrent(3).with_chunk(1), 4..8);
let bufs: Vec<Bytes> = s.try_collect().await.unwrap();
assert_eq!(&bufs[0], "o".as_bytes());
assert_eq!(&bufs[1], "W".as_bytes());
assert_eq!(&bufs[2], "o".as_bytes());
assert_eq!(&bufs[3], "r".as_bytes());
}
}