Write batch for `TransactionDB` in C API

Summary: Closes https://github.com/facebook/rocksdb/pull/2655

Differential Revision: D5600858

Pulled By: yiwu-arbug

fbshipit-source-id: cf52f9104e348438bf168dc6bf7af3837faf12ef

db/c.cc

@@ -3363,6 +3363,16 @@ void rocksdb_transactiondb_put(rocksdb_transactiondb_t* txn_db,
             txn_db->rep->Put(options->rep, Slice(key, klen), Slice(val, vlen)));
 }
 
+//Write batch into transaction db
+void rocksdb_transactiondb_write(
+        rocksdb_transactiondb_t* db,
+        const rocksdb_writeoptions_t* options,
+        rocksdb_writebatch_t* batch,
+        char** errptr) {
+  SaveError(errptr, db->rep->Write(options->rep, &batch->rep));
+}
+
+
 // Delete a key inside a transaction
 void rocksdb_transaction_delete(rocksdb_transaction_t* txn, const char* key,
                                 size_t klen, char** errptr) {

db/c_test.c

@@ -1365,6 +1365,17 @@ int main(int argc, char** argv) {
     CheckNoError(err);
     CheckTxnDBGet(txn_db, roptions, "foo", NULL);
 
+    // write batch into TransactionDB
+    rocksdb_writebatch_t* wb = rocksdb_writebatch_create();
+    rocksdb_writebatch_put(wb, "foo", 3, "a", 1);
+    rocksdb_writebatch_clear(wb);
+    rocksdb_writebatch_put(wb, "bar", 3, "b", 1);
+    rocksdb_writebatch_put(wb, "box", 3, "c", 1);
+    rocksdb_writebatch_delete(wb, "bar", 3);
+    rocksdb_transactiondb_write(txn_db, woptions, wb, &err);
+    CheckTxnDBGet(txn_db, roptions, "box", "c");
+    CheckNoError(err);
+
     // begin a transaction
     txn = rocksdb_transaction_begin(txn_db, woptions, txn_options, NULL);
     // put

include/rocksdb/c.h

@@ -1298,6 +1298,10 @@ extern ROCKSDB_LIBRARY_API void rocksdb_transactiondb_put(
     rocksdb_transactiondb_t* txn_db, const rocksdb_writeoptions_t* options,
     const char* key, size_t klen, const char* val, size_t vlen, char** errptr);
 
+extern ROCKSDB_LIBRARY_API void rocksdb_transactiondb_write(
+    rocksdb_transactiondb_t* txn_db, const rocksdb_writeoptions_t* options,
+    rocksdb_writebatch_t *batch, char** errptr);
+
 extern ROCKSDB_LIBRARY_API void rocksdb_transaction_delete(
     rocksdb_transaction_t* txn, const char* key, size_t klen, char** errptr);