core: replace bundle checksum with BLAKE3

BLAKE3 has a verified streaming mode (Bao), which allows variable chunk
sizes without altering the root hash. This means that a BLAKE3 hash can
serve as a long-term stable content address in location-independent
storage (as demonstrated by iroh).

Signed-off-by: Kim Altintop <kim@eagain.io>

3 files changed, 7 insertions, 15 deletions

diff --git a/src/bundle/fetch.rs b/src/bundle/fetch.rs
index 4e58000..ff10e27 100644
--- a/src/bundle/fetch.rs
+++ b/src/bundle/fetch.rs
@@ -22,10 +22,6 @@ use either::Either::{
     Left,
     Right,
 };
-use sha2::{
-    Digest,
-    Sha256,
-};
 use tempfile::NamedTempFile;
 use url::Url;
 
@@ -96,13 +92,13 @@ impl Fetcher {
                 LockedFile::atomic(&path, true, LockedFile::DEFAULT_PERMISSIONS)?
             };
 
-            let mut out = HashWriter::new(Sha256::new(), &mut lck);
+            let mut out = HashWriter::new(blake3::Hasher::new(), &mut lck);
             out.write_all(&buf)?;
 
             let len = buf.len() as u64 + io::copy(&mut body.take(expect.len), &mut out)?;
-            let checksum = out.hash().into();
+            let checksum = bundle::Checksum::from(out.hasher());
             if let Some(chk) = expect.checksum {
-                ensure!(chk == checksum, "checksum mismatch");
+                ensure!(chk == &checksum, "checksum mismatch");
             }
             lck.seek(SeekFrom::Start(0))?;
             let header = Header::from_reader(&mut lck)?;
diff --git a/src/bundle/header.rs b/src/bundle/header.rs
index 6f3dfe3..d296af1 100644
--- a/src/bundle/header.rs
+++ b/src/bundle/header.rs
@@ -12,15 +12,13 @@ use std::{
     str::FromStr,
 };
 
+use digest::Digest;
 use hex::{
     FromHex,
     FromHexError,
 };
 use refs::Refname;
-use sha2::{
-    Digest,
-    Sha256,
-};
+use sha2::Sha256;
 
 use super::error;
 use crate::{
diff --git a/src/bundle/list.rs b/src/bundle/list.rs
index 21753fa..ea6296f 100644
--- a/src/bundle/list.rs
+++ b/src/bundle/list.rs
@@ -19,11 +19,9 @@ use std::{
 };
 
 use anyhow::anyhow;
+use digest::Digest;
 use once_cell::sync::Lazy;
-use sha2::{
-    Digest,
-    Sha256,
-};
+use sha2::Sha256;
 use url::Url;
 
 use crate::git::{