From e9c42bca347e3a67f8d6bae953bdf0b53ce37d00 Mon Sep 17 00:00:00 2001
From: Alex Auvolat <alex@adnab.me>
Date: Fri, 23 Feb 2024 12:22:29 +0100
Subject: [PATCH] [refactor-block] add DataBlockStream type

---
 src/block/block.rs   |  5 +++++
 src/block/manager.rs | 27 +++++++++++++--------------
 2 files changed, 18 insertions(+), 14 deletions(-)

diff --git a/src/block/block.rs b/src/block/block.rs
index 0b14bad4..3f5c4f94 100644
--- a/src/block/block.rs
+++ b/src/block/block.rs
@@ -7,6 +7,8 @@ use zstd::stream::Encoder;
 use garage_util::data::*;
 use garage_util::error::*;
 
+use garage_net::stream::ByteStream;
+
 #[derive(Debug, Serialize, Deserialize, Copy, Clone)]
 pub enum DataBlockHeader {
 	Plain,
@@ -25,6 +27,9 @@ pub type DataBlock = DataBlockElem<Bytes>;
 /// A path to a possibly compressed block of data
 pub type DataBlockPath = DataBlockElem<PathBuf>;
 
+/// A stream of possibly compressed block data
+pub type DataBlockStream = DataBlockElem<ByteStream>;
+
 impl DataBlockHeader {
 	pub fn is_compressed(&self) -> bool {
 		matches!(self, DataBlockHeader::Compressed)
diff --git a/src/block/manager.rs b/src/block/manager.rs
index 6303248a..6773dfd1 100644
--- a/src/block/manager.rs
+++ b/src/block/manager.rs
@@ -229,11 +229,9 @@ impl BlockManager {
 		&self,
 		hash: &Hash,
 		order_tag: Option<OrderTag>,
-	) -> Result<(DataBlockHeader, ByteStream), Error> {
-		self.rpc_get_raw_block_internal(hash, order_tag, |header, stream| async move {
-			Ok((header, stream))
-		})
-		.await
+	) -> Result<DataBlockStream, Error> {
+		self.rpc_get_raw_block_internal(hash, order_tag, |stream| async move { Ok(stream) })
+			.await
 	}
 
 	/// Ask nodes that might have a (possibly compressed) block for it
@@ -243,7 +241,8 @@ impl BlockManager {
 		hash: &Hash,
 		order_tag: Option<OrderTag>,
 	) -> Result<DataBlock, Error> {
-		self.rpc_get_raw_block_internal(hash, order_tag, |header, stream| async move {
+		self.rpc_get_raw_block_internal(hash, order_tag, |block_stream| async move {
+			let (header, stream) = block_stream.into_parts();
 			read_stream_to_end(stream)
 				.await
 				.err_context("error in block data stream")
@@ -259,7 +258,7 @@ impl BlockManager {
 		f: F,
 	) -> Result<T, Error>
 	where
-		F: Fn(DataBlockHeader, ByteStream) -> Fut,
+		F: Fn(DataBlockStream) -> Fut,
 		Fut: futures::Future<Output = Result<T, Error>>,
 	{
 		let who = self.replication.read_nodes(hash);
@@ -281,8 +280,8 @@ impl BlockManager {
 							continue;
 						}
 					};
-					let (header, stream) = match res.into_parts() {
-						(Ok(BlockRpc::PutBlock { hash: _, header }), Some(stream)) => (header, stream),
+					let block_stream = match res.into_parts() {
+						(Ok(BlockRpc::PutBlock { hash: _, header }), Some(stream)) => DataBlockStream::from_parts(header, stream),
 						(Ok(_), _) => {
 							debug!("Get block {:?}: node {:?} returned a malformed response", hash, node);
 							continue;
@@ -292,7 +291,7 @@ impl BlockManager {
 							continue;
 						}
 					};
-					match f(header, stream).await {
+					match f(block_stream).await {
 						Ok(ret) => return Ok(ret),
 						Err(e) => {
 							debug!("Get block {:?}: error reading stream from node {:?}: {}", hash, node, e);
@@ -316,14 +315,14 @@ impl BlockManager {
 
 	// ---- Public interface ----
 
-	/// Ask nodes that might have a block for it,
-	/// return it as a stream
+	/// Ask nodes that might have a block for it, return it as a stream
 	pub async fn rpc_get_block_streaming(
 		&self,
 		hash: &Hash,
 		order_tag: Option<OrderTag>,
 	) -> Result<ByteStream, Error> {
-		let (header, stream) = self.rpc_get_raw_block_streaming(hash, order_tag).await?;
+		let block_stream = self.rpc_get_raw_block_streaming(hash, order_tag).await?;
+		let (header, stream) = block_stream.into_parts();
 		match header {
 			DataBlockHeader::Plain => Ok(stream),
 			DataBlockHeader::Compressed => {
@@ -336,7 +335,7 @@ impl BlockManager {
 		}
 	}
 
-	/// Ask nodes that might have a block for it
+	/// Ask nodes that might have a block for it, return it as one big Bytes
 	pub async fn rpc_get_block(
 		&self,
 		hash: &Hash,