Merge pull request #78 from kaedroho/writebatch-len-and-is_empty

Implement len() and is_empty() methods on WriteBatch

src/rocksdb.rs

@@ -795,6 +795,16 @@ impl Writable for DB {
     }
 }
 
+impl WriteBatch {
+    pub fn len(&self) -> usize {
+        unsafe { rocksdb_ffi::rocksdb_writebatch_count(self.inner) as usize }
+    }
+
+    pub fn is_empty(&self) -> bool {
+        self.len() == 0
+    }
+}
+
 impl Default for WriteBatch {
     fn default() -> WriteBatch {
         WriteBatch {
@@ -1022,7 +1032,11 @@ fn writebatch_works() {
             // test put
             let batch = WriteBatch::default();
             assert!(db.get(b"k1").unwrap().is_none());
+            assert_eq!(batch.len(), 0);
+            assert!(batch.is_empty());
             let _ = batch.put(b"k1", b"v1111");
+            assert_eq!(batch.len(), 1);
+            assert!(!batch.is_empty());
             assert!(db.get(b"k1").unwrap().is_none());
             let p = db.write(batch);
             assert!(p.is_ok());
@@ -1033,6 +1047,8 @@ fn writebatch_works() {
             // test delete
             let batch = WriteBatch::default();
             let _ = batch.delete(b"k1");
+            assert_eq!(batch.len(), 1);
+            assert!(!batch.is_empty());
             let p = db.write(batch);
             assert!(p.is_ok());
             assert!(db.get(b"k1").unwrap().is_none());