Surface shred version more in tools (#8163)

automerge

ledger/src/lib.rs

@@ -15,6 +15,7 @@ pub mod leader_schedule_utils;
 pub mod poh;
 pub mod rooted_slot_iterator;
 pub mod shred;
+pub mod shred_version;
 pub mod sigverify_shreds;
 pub mod snapshot_package;
 pub mod snapshot_utils;

ledger/src/shred_version.rs

@@ -0,0 +1,44 @@
+use crate::shred::Shred;
+use solana_runtime::hard_forks::HardForks;
+use solana_sdk::hash::{extend_and_hash, Hash};
+
+pub fn compute_shred_version(genesis_hash: &Hash, hard_forks: Option<&HardForks>) -> u16 {
+    use byteorder::{ByteOrder, LittleEndian};
+
+    let mut hash = *genesis_hash;
+    if let Some(hard_forks) = hard_forks {
+        for (slot, count) in hard_forks.iter() {
+            let mut buf = [0u8; 16];
+            LittleEndian::write_u64(&mut buf[..8], *slot);
+            LittleEndian::write_u64(&mut buf[8..], *count as u64);
+            hash = extend_and_hash(&hash, &buf);
+        }
+    }
+
+    Shred::version_from_hash(&hash)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_compute_shred_version() {
+        assert_eq!(compute_shred_version(&Hash::default(), None), 1);
+        let mut hard_forks = HardForks::default();
+        assert_eq!(
+            compute_shred_version(&Hash::default(), Some(&hard_forks)),
+            1
+        );
+        hard_forks.register(1);
+        assert_eq!(
+            compute_shred_version(&Hash::default(), Some(&hard_forks)),
+            55551
+        );
+        hard_forks.register(1);
+        assert_eq!(
+            compute_shred_version(&Hash::default(), Some(&hard_forks)),
+            46353
+        );
+    }
+}