Add new function to get storage changes from snapshot or initial

src/rollbacks.rs

@@ -24,13 +24,11 @@ impl<K: Clone + Hash + Eq, V: Clone> RollbackableHashMap<K, V> {
     pub fn get_logs_after_snapshot(
         &self,
         snapshot: <RollbackableHashMap<K, V> as Rollbackable>::Snapshot,
-    ) -> HashMap<K, V> {
+    ) -> HashMap<K, (Option<V>, V)> {
         let mut changes = HashMap::new();
 
         for (key, value) in self.map.iter() {
-            if !snapshot.contains_key(key) || snapshot.get(key).is_none() {
-                changes.insert(key.clone(), value.clone());
-            }
+            changes.insert(key.clone(), (snapshot.get(key).cloned(), value.clone()));
         }
 
         changes

src/state.rs

@@ -279,6 +279,22 @@ impl VMState {
             })
             .collect()
     }
+
+    /// returns the values that have actually changed from the snapshot storage or the initial if the latter does not exist
+    /// also, a flag is also retured indicating if the value existed on the initial storage
+    pub fn get_storage_changes_from_snapshot(
+        &self,
+        snapshot: <RollbackableHashMap<StorageKey, U256> as Rollbackable>::Snapshot,
+    ) -> Vec<(StorageKey, (Option<U256>, U256, bool))> {
+        self.storage_changes
+            .get_logs_after_snapshot(snapshot)
+            .iter()
+            .map(|(key, (before, after))| {
+                let initial = self.initial_values.get(key).unwrap_or(&None);
+                (*key, (before.or(*initial), *after, initial.is_none()))
+            })
+            .collect()
+    }
 }
 
 #[derive(Clone, Default, PartialEq, Debug)]