Expose rocksdb_options_copy function to the C API (#6880)

Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/6880

Reviewed By: ajkr

Differential Revision: D21842752

Pulled By: pdillinger

fbshipit-source-id: eda326f551ddd9cb397681544b9e9799ea614e52

db/c.cc

@@ -2154,6 +2154,10 @@ void rocksdb_options_destroy(rocksdb_options_t* options) {
   delete options;
 }
 
+rocksdb_options_t* rocksdb_options_create_copy(rocksdb_options_t* options) {
+  return new rocksdb_options_t(*options);
+}
+
 void rocksdb_options_increase_parallelism(
     rocksdb_options_t* opt, int total_threads) {
   opt->rep.IncreaseParallelism(total_threads);

db/c_test.c

@@ -1461,6 +1461,23 @@ int main(int argc, char** argv) {
     rocksdb_cuckoo_options_destroy(cuckoo_options);
   }
 
+  StartPhase("options");
+  {
+    rocksdb_options_t* o;
+    o = rocksdb_options_create();
+    rocksdb_options_set_create_if_missing(o, 1);
+
+    rocksdb_options_t* copy;
+    copy = rocksdb_options_create_copy(o);
+    // TODO: some way to check that *copy == *o
+
+    rocksdb_options_set_create_if_missing(copy, 0);
+    // TODO: some way to check that *copy != *o
+
+    rocksdb_options_destroy(copy);
+    rocksdb_options_destroy(o);
+  }
+
   StartPhase("iterate_upper_bound");
   {
     // Create new empty database

include/rocksdb/c.h

@@ -771,6 +771,8 @@ extern ROCKSDB_LIBRARY_API void rocksdb_set_options_cf(
 
 extern ROCKSDB_LIBRARY_API rocksdb_options_t* rocksdb_options_create();
 extern ROCKSDB_LIBRARY_API void rocksdb_options_destroy(rocksdb_options_t*);
+extern ROCKSDB_LIBRARY_API rocksdb_options_t* rocksdb_options_create_copy(
+    rocksdb_options_t*);
 extern ROCKSDB_LIBRARY_API void rocksdb_options_increase_parallelism(
     rocksdb_options_t* opt, int total_threads);
 extern ROCKSDB_LIBRARY_API void rocksdb_options_optimize_for_point_lookup(