proxmox-backup/src/tools/wrapped_reader_stream.rs

63 lines
1.9 KiB
Rust
Raw Normal View History

use failure::*;
use tokio_threadpool;
use tokio::io::{AsyncRead};
use std::io::Read;
use futures::Async;
use futures::stream::Stream;
use std::io::ErrorKind::{Other, WouldBlock};
pub struct WrappedReaderStream<R: Read> {
reader: R,
}
impl <R: Read> WrappedReaderStream<R> {
pub fn new(reader: R) -> Self {
Self { reader }
}
}
impl <R: Read> Read for WrappedReaderStream<R> {
fn read(&mut self, buf: &mut [u8]) -> std::io::Result<usize> {
//tokio::io::would_block(|| self.reader.read(buf))
// fixme: howto??
match tokio_threadpool::blocking(|| self.reader.read(buf)) {
Ok(Async::Ready(res)) => res,
Ok(Async::NotReady) => Err(WouldBlock.into()),
Err(err) => Err(std::io::Error::new(Other, "`blocking` annotated I/O must be called \
from the context of the Tokio runtime.")),
}
}
}
impl <R: Read> AsyncRead for WrappedReaderStream<R> {
// fixme:???!!?
unsafe fn prepare_uninitialized_buffer(&self, _: &mut [u8]) -> bool {
false
}
}
impl <R: Read> Stream for WrappedReaderStream<R> {
type Item = Vec<u8>;
type Error = std::io::Error;
fn poll(&mut self) -> Result<Async<Option<Vec<u8>>>, std::io::Error> {
let mut buf = [0u8;64*1024];
match self.poll_read(&mut buf) {
Ok(Async::Ready(n)) => {
// By convention, if an AsyncRead says that it read 0 bytes,
// we should assume that it has got to the end, so we signal that
// the Stream is done in this case by returning None:
if n == 0 {
Ok(Async::Ready(None))
} else {
Ok(Async::Ready(Some(buf[..n].to_vec())))
}
},
Ok(Async::NotReady) => Ok(Async::NotReady),
Err(e) => Err(e)
}
}
}