feat(stages): checkpoint hashing stages into a new table (#2735)

crates/primitives/src/checkpoints.rs

@@ -138,6 +138,40 @@ impl StageCheckpoint {
     pub fn new(block_number: BlockNumber) -> Self {
         Self { block_number, ..Default::default() }
     }
+
+    /// Returns the account hashing stage checkpoint, if any.
+    pub fn account_hashing_stage_checkpoint(&self) -> Option<AccountHashingCheckpoint> {
+        match self.stage_checkpoint {
+            Some(StageUnitCheckpoint::Account(checkpoint)) => Some(checkpoint),
+            _ => None,
+        }
+    }
+
+    /// Returns the storage hashing stage checkpoint, if any.
+    pub fn storage_hashing_stage_checkpoint(&self) -> Option<StorageHashingCheckpoint> {
+        match self.stage_checkpoint {
+            Some(StageUnitCheckpoint::Storage(checkpoint)) => Some(checkpoint),
+            _ => None,
+        }
+    }
+
+    /// Sets the stage checkpoint to account hashing.
+    pub fn with_account_hashing_stage_checkpoint(
+        mut self,
+        checkpoint: AccountHashingCheckpoint,
+    ) -> Self {
+        self.stage_checkpoint = Some(StageUnitCheckpoint::Account(checkpoint));
+        self
+    }
+
+    /// Sets the stage checkpoint to storage hashing.
+    pub fn with_storage_hashing_stage_checkpoint(
+        mut self,
+        checkpoint: StorageHashingCheckpoint,
+    ) -> Self {
+        self.stage_checkpoint = Some(StageUnitCheckpoint::Storage(checkpoint));
+        self
+    }
 }
 
 // TODO(alexey): ideally, we'd want to display block number + stage-specific metric (if available)