move client to pbs-client subcrate

Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>

pbs-client/src/pipe_to_stream.rs

@@ -0,0 +1,70 @@
+// Implement simple flow control for h2 client
+//
+// See also: hyper/src/proto/h2/mod.rs
+
+use std::pin::Pin;
+use std::task::{Context, Poll};
+
+use anyhow::{format_err, Error};
+use bytes::Bytes;
+use futures::{ready, Future};
+use h2::SendStream;
+
+pub struct PipeToSendStream {
+    body_tx: SendStream<Bytes>,
+    data: Option<Bytes>,
+}
+
+impl PipeToSendStream {
+    pub fn new(data: Bytes, tx: SendStream<Bytes>) -> PipeToSendStream {
+        PipeToSendStream {
+            body_tx: tx,
+            data: Some(data),
+        }
+    }
+}
+
+impl Future for PipeToSendStream {
+    type Output = Result<(), Error>;
+
+    fn poll(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Self::Output> {
+        let this = self.get_mut();
+
+        if this.data != None {
+            // just reserve 1 byte to make sure there's some
+            // capacity available. h2 will handle the capacity
+            // management for the actual body chunk.
+            this.body_tx.reserve_capacity(1);
+
+            if this.body_tx.capacity() == 0 {
+                loop {
+                    match ready!(this.body_tx.poll_capacity(cx)) {
+                        Some(Err(err)) => return Poll::Ready(Err(Error::from(err))),
+                        Some(Ok(0)) => {}
+                        Some(Ok(_)) => break,
+                        None => return Poll::Ready(Err(format_err!("protocol canceled"))),
+                    }
+                }
+            } else if let Poll::Ready(reset) = this.body_tx.poll_reset(cx) {
+                return Poll::Ready(Err(match reset {
+                    Ok(reason) => format_err!("stream received RST_STREAM: {:?}", reason),
+                    Err(err) => Error::from(err),
+                }));
+            }
+
+            this.body_tx
+                .send_data(this.data.take().unwrap(), true)
+                .map_err(Error::from)?;
+
+            Poll::Ready(Ok(()))
+        } else {
+            if let Poll::Ready(reset) = this.body_tx.poll_reset(cx) {
+                return Poll::Ready(Err(match reset {
+                    Ok(reason) => format_err!("stream received RST_STREAM: {:?}", reason),
+                    Err(err) => Error::from(err),
+                }));
+            }
+            Poll::Ready(Ok(()))
+        }
+    }
+}