delete all dag block in sync dag store to protect the blocks not int … (

#4165)

* delete all dag block in sync dag store to protect the blocks not int he blue fork

* add testing code

sync/src/store/sync_absent_ancestor.rs

@@ -45,6 +45,7 @@ pub trait AbsentDagBlockStoreReader {
 pub trait AbsentDagBlockStoreWriter {
     fn save_absent_block(&self, blocks: Vec<DagSyncBlock>) -> anyhow::Result<()>;
     fn delete_absent_block(&self, number: BlockNumber, block_id: HashValue) -> anyhow::Result<()>;
+    fn delete_all_absent_block(&self) -> anyhow::Result<()>;
 }
 
 pub(crate) const SYNC_ABSENT_BLOCK_CF: &str = "sync-absent-block";
@@ -187,4 +188,10 @@ impl AbsentDagBlockStoreWriter for SyncAbsentBlockStore {
         }
         Ok(())
     }
+
+    fn delete_all_absent_block(&self) -> anyhow::Result<()> {
+        self.cache_access
+            .delete_all(DirectDbWriter::new(&self.db))
+            .map_err(|e| format_err!("failed to delete all absent block: {:?}", e))
+    }
 }

sync/src/store/sync_dag_store.rs

@@ -149,4 +149,8 @@ impl SyncDagStore {
                 e
             })
     }
+
+    pub(crate) fn delete_all_dag_sync_block(&self) -> anyhow::Result<()> {
+        self.absent_dag_store.delete_all_absent_block()
+    }
 }

sync/src/store/tests.rs

@@ -184,5 +184,13 @@ fn test_write_read_in_order() -> anyhow::Result<()> {
 
     assert_eq!(expect_order, db_order);
 
+    let mut iter_to_see_empty = sync_dag_store.iter_at_first()?;
+    assert!(iter_to_see_empty.next().is_some());
+
+    sync_dag_store.delete_all_dag_sync_block()?;
+
+    iter_to_see_empty = sync_dag_store.iter_at_first()?;
+    assert!(iter_to_see_empty.next().is_none());
+
     Ok(())
 }

sync/src/tasks/inner_sync_task.rs

@@ -186,6 +186,8 @@ where
                     }
                 }
             }
+            // clear the dag sync if fork happened
+            self.sync_dag_store.delete_all_dag_sync_block()?;
 
             Ok(TaskGenerator::new(
                 block_sync_task,