Add `DB::latest_sequence_number` method. (#326)

CHANGELOG.md

@@ -9,6 +9,7 @@
 * Bumped RocksDB to 6.1.2 (lispy)
 * Added `Sync` and `Send` implementations to `Snapshot` (pavel-mukhanov)
 * Added `raw_iterator_cf_opt` to the DB API (rnarubin)
+* Added `DB::latest_sequence_number` method (vitvakatu)
 
 ## 0.12.2 (2019-05-03)
 

src/db.rs

@@ -1560,6 +1560,11 @@ impl DB {
             Err(e) => Err(e),
         }
     }
+
+    /// The sequence number of the most recent transaction.
+    pub fn latest_sequence_number(&self) -> u64 {
+        unsafe { ffi::rocksdb_get_latest_sequence_number(self.inner) }
+    }
 }
 
 impl WriteBatch {

tests/test_db.rs

@@ -240,3 +240,14 @@ fn set_option_test() {
         db.set_options(&multiple_options).unwrap();
     }
 }
+
+#[test]
+fn test_sequence_number() {
+    let path = DBPath::new("_rust_rocksdb_test_sequence_number");
+    {
+        let db = DB::open_default(&path).unwrap();
+        assert_eq!(db.latest_sequence_number(), 0);
+        db.put(b"key", b"value");
+        assert_eq!(db.latest_sequence_number(), 1);
+    }
+}