From 9b41f4ff2016b099ee706747828f5828f8c96b1c Mon Sep 17 00:00:00 2001
From: Alex Auvolat <alex@adnab.me>
Date: Fri, 23 Feb 2024 11:46:57 +0100
Subject: [refactor-block] move read_stream_to_end to garage_net

---
 src/block/manager.rs | 22 ++++------------------
 src/net/bytes_buf.rs | 13 +++++++++++++
 src/net/stream.rs    | 11 +++++++++++
 3 files changed, 28 insertions(+), 18 deletions(-)

diff --git a/src/block/manager.rs b/src/block/manager.rs
index 96ea2c96..54290888 100644
--- a/src/block/manager.rs
+++ b/src/block/manager.rs
@@ -8,7 +8,6 @@ use bytes::Bytes;
 use rand::prelude::*;
 use serde::{Deserialize, Serialize};
 
-use futures_util::stream::StreamExt;
 use tokio::fs;
 use tokio::io::{AsyncReadExt, AsyncWriteExt, BufReader};
 use tokio::sync::{mpsc, Mutex, MutexGuard};
@@ -18,7 +17,7 @@ use opentelemetry::{
 	Context,
 };
 
-use garage_net::stream::{stream_asyncread, ByteStream};
+use garage_net::stream::{read_stream_to_end, stream_asyncread, ByteStream};
 
 use garage_db as db;
 
@@ -247,7 +246,8 @@ impl BlockManager {
 		self.rpc_get_raw_block_internal(hash, order_tag, |header, stream| async move {
 			read_stream_to_end(stream)
 				.await
-				.map(|data| DataBlock::from_parts(header, data))
+				.err_context("error in block data stream")
+				.map(|data| DataBlock::from_parts(header, data.into_bytes()))
 		})
 		.await
 	}
@@ -477,7 +477,7 @@ impl BlockManager {
 		stream: Option<ByteStream>,
 	) -> Result<(), Error> {
 		let stream = stream.ok_or_message("missing stream")?;
-		let bytes = read_stream_to_end(stream).await?;
+		let bytes = read_stream_to_end(stream).await?.into_bytes();
 		let data = DataBlock::from_parts(header, bytes);
 		self.write_block(&hash, &data).await
 	}
@@ -823,20 +823,6 @@ impl BlockManagerLocked {
 	}
 }
 
-async fn read_stream_to_end(mut stream: ByteStream) -> Result<Bytes, Error> {
-	let mut parts: Vec<Bytes> = vec![];
-	while let Some(part) = stream.next().await {
-		parts.push(part.ok_or_message("error in stream")?);
-	}
-
-	Ok(parts
-		.iter()
-		.map(|x| &x[..])
-		.collect::<Vec<_>>()
-		.concat()
-		.into())
-}
-
 struct DeleteOnDrop(Option<PathBuf>);
 
 impl DeleteOnDrop {
diff --git a/src/net/bytes_buf.rs b/src/net/bytes_buf.rs
index 3929a860..1d928ffb 100644
--- a/src/net/bytes_buf.rs
+++ b/src/net/bytes_buf.rs
@@ -3,6 +3,8 @@ use std::collections::VecDeque;
 
 use bytes::BytesMut;
 
+use crate::stream::ByteStream;
+
 pub use bytes::Bytes;
 
 /// A circular buffer of bytes, internally represented as a list of Bytes
@@ -119,6 +121,17 @@ impl BytesBuf {
 	pub fn into_slices(self) -> VecDeque<Bytes> {
 		self.buf
 	}
+
+	/// Return the entire buffer concatenated into a single big Bytes
+	pub fn into_bytes(mut self) -> Bytes {
+		self.take_all()
+	}
+
+	/// Return the content as a stream of individual chunks
+	pub fn into_stream(self) -> ByteStream {
+		use futures::stream::StreamExt;
+		Box::pin(futures::stream::iter(self.buf).map(|x| Ok(x)))
+	}
 }
 
 impl Default for BytesBuf {
diff --git a/src/net/stream.rs b/src/net/stream.rs
index 88c3fed4..3ac6896d 100644
--- a/src/net/stream.rs
+++ b/src/net/stream.rs
@@ -200,3 +200,14 @@ pub fn asyncread_stream<R: AsyncRead + Send + Sync + 'static>(reader: R) -> Byte
 pub fn stream_asyncread(stream: ByteStream) -> impl AsyncRead + Send + Sync + 'static {
 	tokio_util::io::StreamReader::new(stream)
 }
+
+/// Reads all of the content of a `ByteStream` into a BytesBuf
+/// that contains everything
+pub async fn read_stream_to_end(mut stream: ByteStream) -> Result<BytesBuf, std::io::Error> {
+	let mut buf = BytesBuf::new();
+	while let Some(part) = stream.next().await {
+		buf.extend(part?);
+	}
+
+	Ok(buf)
+}
-- 
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