tools/wrapped_reader_stream.rs: new helper class

Will use that to download catar files.

src/tools.rs

@@ -20,6 +20,7 @@ use std::os::unix::io::AsRawFd;
 use serde_json::Value;
 
 pub mod timer;
+pub mod wrapped_reader_stream;
 
 /// The `BufferedReader` trait provides a single function
 /// `buffered_read`. It returns a reference to an internal buffer. The

src/tools/wrapped_reader_stream.rs

@@ -0,0 +1,55 @@
+use failure::*;
+use tokio::io::{AsyncRead};
+use std::io::Read;
+use futures::Async;
+use futures::stream::Stream;
+
+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??
+        self.reader.read(buf)
+    }
+}
+
+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)
+        }
+    }
+}