From 605a630333c8ee60c55fe011a375c01277bba173 Mon Sep 17 00:00:00 2001
From: Alex Auvolat <alex@adnab.me>
Date: Fri, 22 Jul 2022 18:20:27 +0200
Subject: Use streaming in block manager

---
 src/block/block.rs | 37 ++++++++++++++++++++++++++++---------
 1 file changed, 28 insertions(+), 9 deletions(-)

(limited to 'src/block/block.rs')

diff --git a/src/block/block.rs b/src/block/block.rs
index f17bd2c0..935aa900 100644
--- a/src/block/block.rs
+++ b/src/block/block.rs
@@ -5,13 +5,18 @@ use zstd::stream::{decode_all as zstd_decode, Encoder};
 use garage_util::data::*;
 use garage_util::error::*;
 
+#[derive(Debug, Serialize, Deserialize, Copy, Clone)]
+pub enum DataBlockHeader {
+	Plain,
+	Compressed,
+}
+
 /// A possibly compressed block of data
-#[derive(Debug, Serialize, Deserialize)]
 pub enum DataBlock {
 	/// Uncompressed data
-	Plain(#[serde(with = "serde_bytes")] Vec<u8>),
+	Plain(Bytes),
 	/// Data compressed with zstd
-	Compressed(#[serde(with = "serde_bytes")] Vec<u8>),
+	Compressed(Bytes),
 }
 
 impl DataBlock {
@@ -31,7 +36,7 @@ impl DataBlock {
 	/// Get the buffer, possibly decompressing it, and verify it's integrity.
 	/// For Plain block, data is compared to hash, for Compressed block, zstd checksumming system
 	/// is used instead.
-	pub fn verify_get(self, hash: Hash) -> Result<Vec<u8>, Error> {
+	pub fn verify_get(self, hash: Hash) -> Result<Bytes, Error> {
 		match self {
 			DataBlock::Plain(data) => {
 				if blake2sum(&data) == hash {
@@ -40,9 +45,9 @@ impl DataBlock {
 					Err(Error::CorruptData(hash))
 				}
 			}
-			DataBlock::Compressed(data) => {
-				zstd_decode(&data[..]).map_err(|_| Error::CorruptData(hash))
-			}
+			DataBlock::Compressed(data) => zstd_decode(&data[..])
+				.map_err(|_| Error::CorruptData(hash))
+				.map(Bytes::from),
 		}
 	}
 
@@ -66,14 +71,28 @@ impl DataBlock {
 		tokio::task::spawn_blocking(move || {
 			if let Some(level) = level {
 				if let Ok(data) = zstd_encode(&data[..], level) {
-					return DataBlock::Compressed(data);
+					return DataBlock::Compressed(data.into());
 				}
 			}
-			DataBlock::Plain(data.to_vec()) // TODO: remove to_vec here
+			DataBlock::Plain(data)
 		})
 		.await
 		.unwrap()
 	}
+
+	pub fn into_parts(self) -> (DataBlockHeader, Bytes) {
+		match self {
+			DataBlock::Plain(data) => (DataBlockHeader::Plain, data),
+			DataBlock::Compressed(data) => (DataBlockHeader::Compressed, data),
+		}
+	}
+
+	pub fn from_parts(h: DataBlockHeader, bytes: Bytes) -> Self {
+		match h {
+			DataBlockHeader::Plain => DataBlock::Plain(bytes),
+			DataBlockHeader::Compressed => DataBlock::Compressed(bytes),
+		}
+	}
 }
 
 fn zstd_encode<R: std::io::Read>(mut source: R, level: i32) -> std::io::Result<Vec<u8>> {
-- 
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