From 60ac5ed154940e4ab24360c75c62cbb6664723a2 Mon Sep 17 00:00:00 2001
From: Damien Lachaume <135982616+dlachaume@users.noreply.github.com>
Date: Tue, 24 Dec 2024 16:28:32 +0100
Subject: [PATCH] feat: ensure `CardanoDatabaseSnapshot` identifiers are unique
 by computing a unique hash

---
 .../src/entities/cardano_database.rs          | 127 +++++++++++++++++-
 1 file changed, 124 insertions(+), 3 deletions(-)

diff --git a/mithril-common/src/entities/cardano_database.rs b/mithril-common/src/entities/cardano_database.rs
index f6ee441f5c..2b75298923 100644
--- a/mithril-common/src/entities/cardano_database.rs
+++ b/mithril-common/src/entities/cardano_database.rs
@@ -1,5 +1,6 @@
 use semver::Version;
 use serde::{Deserialize, Serialize};
+use sha2::{Digest, Sha256};
 use strum::EnumDiscriminants;
 
 use crate::{
@@ -10,6 +11,9 @@ use crate::{
 /// Cardano database snapshot.
 #[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
 pub struct CardanoDatabaseSnapshot {
+    /// Unique hash of the Cardano database snapshot.
+    pub hash: String,
+
     /// Merkle root of the Cardano database snapshot.
     pub merkle_root: String,
 
@@ -41,14 +45,28 @@ impl CardanoDatabaseSnapshot {
     ) -> Self {
         let cardano_node_version = format!("{cardano_node_version}");
 
-        Self {
+        let mut cardano_database_snapshot = Self {
+            hash: "".to_string(),
             merkle_root,
             beacon,
             locations,
             total_db_size_uncompressed,
             compression_algorithm,
             cardano_node_version,
-        }
+        };
+
+        cardano_database_snapshot.hash = cardano_database_snapshot.compute_hash();
+
+        cardano_database_snapshot
+    }
+
+    /// Cardano database snapshot hash computation
+    fn compute_hash(&self) -> String {
+        let mut hasher = Sha256::new();
+        hasher.update(self.beacon.epoch.to_be_bytes());
+        hasher.update(self.merkle_root.as_bytes());
+
+        hex::encode(hasher.finalize())
     }
 }
 
@@ -106,6 +124,109 @@ pub struct ArtifactsLocations {
 #[typetag::serde]
 impl Artifact for CardanoDatabaseSnapshot {
     fn get_id(&self) -> String {
-        self.merkle_root.clone()
+        self.hash.clone()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn dummy() -> CardanoDatabaseSnapshot {
+        CardanoDatabaseSnapshot::new(
+            "mk-root-1111111111".to_string(),
+            CardanoDbBeacon::new(2222, 55555),
+            0,
+            ArtifactsLocations {
+                digests: vec![],
+                immutables: vec![],
+                ancillary: vec![],
+            },
+            CompressionAlgorithm::Gzip,
+            &Version::new(1, 0, 0),
+        )
+    }
+
+    #[test]
+    fn test_cardano_database_snapshot_compute_hash() {
+        let cardano_database_snapshot = CardanoDatabaseSnapshot {
+            merkle_root: "mk-root-123".to_string(),
+            beacon: CardanoDbBeacon::new(123, 98),
+            ..dummy()
+        };
+
+        assert_eq!(
+            "b1cc5e0deaa7856e8e811e349d6e639fa667aa70288602955f438c5893ce29c8",
+            cardano_database_snapshot.compute_hash()
+        );
+    }
+
+    #[test]
+    fn compute_hash_returns_same_hash_with_same_cardano_database_snapshot() {
+        assert_eq!(
+            CardanoDatabaseSnapshot {
+                merkle_root: "mk-root-123".to_string(),
+                beacon: CardanoDbBeacon::new(123, 98),
+                ..dummy()
+            }
+            .compute_hash(),
+            CardanoDatabaseSnapshot {
+                merkle_root: "mk-root-123".to_string(),
+                beacon: CardanoDbBeacon::new(123, 98),
+                ..dummy()
+            }
+            .compute_hash()
+        );
+    }
+
+    #[test]
+    fn compute_hash_returns_different_hash_with_different_merkle_root() {
+        assert_ne!(
+            CardanoDatabaseSnapshot {
+                merkle_root: "mk-root-123".to_string(),
+                beacon: CardanoDbBeacon::new(123, 98),
+                ..dummy()
+            }
+            .compute_hash(),
+            CardanoDatabaseSnapshot {
+                merkle_root: "mk-root-456".to_string(),
+                beacon: CardanoDbBeacon::new(123, 98),
+                ..dummy()
+            }
+            .compute_hash()
+        );
+    }
+
+    #[test]
+    fn compute_hash_returns_different_hash_with_different_beacon() {
+        assert_eq!(
+            CardanoDatabaseSnapshot {
+                merkle_root: "mk-root-123".to_string(),
+                beacon: CardanoDbBeacon::new(123, 98),
+                ..dummy()
+            }
+            .compute_hash(),
+            CardanoDatabaseSnapshot {
+                merkle_root: "mk-root-123".to_string(),
+                beacon: CardanoDbBeacon::new(123, 12),
+                ..dummy()
+            }
+            .compute_hash()
+        );
+
+        assert_ne!(
+            CardanoDatabaseSnapshot {
+                merkle_root: "mk-root-123".to_string(),
+                beacon: CardanoDbBeacon::new(123, 98),
+                ..dummy()
+            }
+            .compute_hash(),
+            CardanoDatabaseSnapshot {
+                merkle_root: "mk-root-123".to_string(),
+                beacon: CardanoDbBeacon::new(456, 98),
+                ..dummy()
+            }
+            .compute_hash()
+        );
     }
 }