use futures::{Async, Poll, Stream};
use hyper::Chunk;
use std::io::Error;
use std::mem;
use tokio::fs::File;
use tokio::io::AsyncRead;
const BUF_SIZE: usize = 8 * 1024;
pub struct FileChunkStream {
file: File,
buf: Box<[u8; BUF_SIZE]>,
}
impl FileChunkStream {
pub fn new(file: File) -> FileChunkStream {
let buf = Box::new(unsafe { mem::uninitialized() });
FileChunkStream { file, buf }
}
}
impl Stream for FileChunkStream {
type Item = Chunk;
type Error = Error;
fn poll(&mut self) -> Poll<Option<Self::Item>, Self::Error> {
match self.file.poll_read(&mut self.buf[..]) {
Ok(Async::Ready(0)) => {
Ok(Async::Ready(None))
},
Ok(Async::Ready(size)) => {
Ok(Async::Ready(Some(self.buf[..size].to_owned().into())))
},
Ok(Async::NotReady) => {
Ok(Async::NotReady)
},
Err(e) => {
Err(e)
},
}
}
}